text:
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 Execut ive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Regulat ory Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.3 Phy sical, Demographic, and Economic Description of the San M anuel Area . . . . 7 1.3.1 Climat e and Physiography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.3.2 Pop ulat ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.3.3 Economy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 1.4 General SIP Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 1.4.1 CAA Section 172(c), Nonattainment Plan Provisions . . . . . . . . . . . . . . . 11 1.4.2 CAA Section 175(A) - M aint enance Plans . . . . . . . . . . . . . . . . . . . . . . . 14 1.4.3 CAA Section 191 and 192 - Plan Submission and Attainment Dates . . . 15 1.4.4 Conformit y Provisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 COM PLIANCE WITH OTHER FEDERAL REGULATIONS . . . . . . . . . . . . . . . . . . 16 SO2 M ONIT ORING NETWORK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 3.1 Current Sampler Type and Siting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 3.2 Ambient Data Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 SO2 EM ISSIONS INVENTORY FOR POINT, AREA AND M OBILE SOURCES . . 26 4.1 SO2 Point Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 4.1.1 Oracle Compressor Station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 4.1.2 BHP Copper San M anuel Smelter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 4.1.3 BHP Copper M ining and M illing Operations . . . . . . . . . . . . . . . . . . . . . 28 4.2 M ajor Point Sources within the 50 km Buffer Area . . . . . . . . . . . . . . . . . . . . . . 28 4.2.1 Ariz ona Public Service (APS) - Red Rock . . . . . . . . . . . . . . . . . . . . . . . . 29 4.2.2 T ucson Electric Power Co. Irvington . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 4.2.3 T ucson Electric Power Co. North Loop . . . . . . . . . . . . . . . . . . . . . . . . . 29 4.2.4 ASARCO Hayden Smelter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 4.3 Area, M obile, and Total Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 4.4 Emissions Projections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 4.4.1 Point Source Projections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 4.4.2 Area, M obile, and Total Source Projections . . . . . . . . . . . . . . . . . . . . . . 32 M ODELING DEM ONST RAT ION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 ii
2.0 3.0
5.2 6.0
Derivat ion of New Emissions Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 5.1.1 St ack Emissions Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 5.1.2 Fugit ive Emissions Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 5.1.3 Emissions Reductions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Smelt er Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
CONT ROL M EASURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 6.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 6.2 Emissions Limitations for BHP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 6.2.1 AC Rule R18-2-715(F)(1), R18-2-715(G) and R18-2-715.01 - Standards of Performance for Existing Primary Copper Smelters: Site specific requirement s; Compliance and M onit oring . . . . . . . . . . . . . . . . . . . . . . . 45 6.2.2 AAC Rule R18-2-715.02 Standards of Performance for Existing Primary Cop p er Smelters; Fugitive Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 6.2.3 BHP Permit Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 M AINT ENANCE PLAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 7.1 M aint enance Demonstration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 7.2 Ambient M onit oring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 7.3 Verificat ion of Continued Attainment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 7.4 Cont ingency Plan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 7.4.1 Not ificat ion Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 7.4.2 First Action Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 7.4.3 Second Action Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 7.4.4 Sp ecial M easure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
CHAPTER ONE: T able 1.1 - Study Area Definition T able 1.2 - Census Information T able 1.3 - Population Projections T able 1.4 - Pinal County Economic Activity T able 1.5 - Labor Force Data for San M anuel CDP CHAPTER THREE: T able 3.1 - Ambient M onit oring Network Data T able 3.2 - Current M onit oring Network T able 3.3 - SO2 Ambient Air Quality M onit oring Data CHAPTER FOUR: T able 4.1 - SO2 Emissions for San M anuel Nonattainment Area - Point Sources T able 4.2 - SO2 Emissions for San M anuel Nonattainment Area - 50 Km. Buffer T able 4.3 - SO2 Emissions for San M anuel Nonattainment Area - All Sources T able 4.4 - SO2 Emission Projections for San M anuel Nonattainment Area - Point Sources T able 4.5 - SO2 Emission Projections for San M anuel Nonattainment Area - 50 Km. Buffer Table 4.6 - SO2 Emission Projections for San M anuel Nonattainment Area - All Sources CHAPTER FIVE: T able 5.1 - San M anuel Smelter Configuration (1974 to Present) T able 5.2 - San M anuel Smelter SO2 Emissions (1974 to Present) T able 5.3 - Emissions Source Distance from Facility Boundary CHAPTER S IX: T able 6.1 - Implementation of SO2 Control Technology T able 6.2 - Permit Conditions
CHAPTER ONE: Figure 1.1 - San M anuel SO2 Nonattainment Area Figure 1.2 - San M anuel SO2 Nonattainment Area Latitude and Longitude CHAPTER THREE: Figure 3.1 - Locations of Fugitive/Stack Ambient M onit or Sites Figure 3.2 - Close-Up of Ambient M onit or Sites CHAPTER FOUR: Figure 4.1 - SO2 Point Sources CHAPTER FIVE: Figure 5.1 - Comparison of 1979 and 2001 M PR Limits Figure 5.2 - 99th Percentile Total Emissions and Ambient Concentrations CHAPTER S IX: Figure 6.1 - Comparison of SO2 Emissions and Percent Control Figure 6.2 - Comparison of SO2 Emissions and Copper Production CHAPTER S EVEN: Figure 7.1 - San M anuel Nonattainment Area SO2 Emissions Projections
1.0 1.1
INTRODUCTION Executive S ummary
T his document includes an attainment demonstration and formal request to the United St at es Environmental Agency (EPA) to redesignate the San M anuel, Arizona area, a nonat t ainment area for sulfur dioxide (SO2 ), to attainment for the health-based 24-hour average and annual average SO2 National Ambient Air Quality Standards (NAAQS). It summarizes the p rogress of the area in attaining the SO2 standard, demonstrates that all Clean Air Act (CAA) requirement s for attainment have been adopted, and includes a maintenance plan to assure cont inued attainment after redesignation. The air quality record included in Chapter 3 of this document shows that ambient air qualit y monitors located in the San M anuel nonattainment area have recorded no violations of the p rimary SO2 NAAQS since 1979 or secondary SO2 NAAQS since 1985. This meets the EPA requirement for demonstrating a minimum of eight consecutive quarters of ambient air quality measurement s that are below the SO2 NAAQS. This document also demonstrates that the emission reduction control measures resp onsible for the air quality improvement are both permanent and enforceable. Based on state p oint source and EPA National Emissions Trends (NET) mobile and area source emissions invent ories, the primary source of SO2 in the nonattainment area is the copper smelter located near San M anuel, Arizona. The 1998 base-year San M anuel nonattainment area emissions invent ory , presented in Chapter 4, lists the sources in the nonattainment area and their SO2 emissions. Details of the of the updated modeling demonstration are contained in Chapter 5. Chap t er 6 describes the primary control measures implemented to achieve attainment. These measures include implementation of reasonably available control measures (RACM ) to reduce emissions from the smelter near San M anuel. Chapter 7 describes in detail measures designed to ensure continued maintenance of the SO2 NAAQS for at least ten years after redesignation of the area to attainment. The clean air quality record, enforceable control measures, and projections of future emissions presented in this document, all demonstrate that the area has attained and will continue t o maintain the SO2 air quality standards. With this submittal, ADEQ requests that EPA ap p rove this attainment demonstration and maintenance plan for the San M anuel SO2 nonat t ainment area and redesignate the area to attainment for the 24-hour and annual NAAQS. 1.2 Regulatory Background
T he federal air quality standards for SO2 were established to identify maximum ambient concent rat ions above which adverse effects on human health and welfare may occur. Accordingly, the SO2 standards are divided into two types: primary and secondary. The primary st andards are based on the protection of public health and the secondary standard is based on 1
p rot ect ion of the environment, including protection against damage to animals, vegetation, buildings, and decreased visibility. The original national primary and secondary NAAQS for SO2 were codified in Volume 42 of the Code of Federal Regulations, Part 410 (42 CFR 410) on April 30, 1971, (36 FR 81875) and recodified to 40 CFR 50.4 and 50.5 on November 25, 1971 (36 FR 22384). On M ay 22, 1996, the EPA promulgated the current primary and secondary NAAQS for SO2 (61 FR 25566) as follows:1
Standard 2 P rimary S econdary Annual 0. 030 ppm (80 Fg/m3 ) 24-hour 0. 14 ppm (365 Fg/m3 ) 0. 5 ppm (1300 Fg/m3 ) 3-hour
Areas that do not meet the NAAQS may be designated nonattainment for the respective st andard. The San M anuel SO2 nonattainment area initially comprised all of Pima and Pinal Count ies (43 FR 8968, M arch 3, 1978) but at the request of the state of Arizona, the boundaries were subsequently reduced to eleven townships in and around San M anuel (44 FR 21261, April 10, 1979). In addition, four adjacent townships were designated as unclassified (See Figure 1.1 for location map).
Several technical changes were made at this time including stating the standards in parts per million (ppm) to make the SO2
NAAQS consistent with those for other pollutants. The former standards, stated in micrograms per cubic meter (ug/m3) are in parentheses. 2
Violations of the primary and secondary standards are determined as follows: The annual arithmetic mean of measured
h o u rly ambient SO2 concentrations must not exceed the level of the annual standard in a calendar year. The 24-hour and 3-hour averages of meas u red concentrations must not exceed the level of the respective standard more than once per calendar year (two exceedances of the s tan d ard per year is a violation of that standard).
All but one of the townships that define the nonattainment area are located in southeastern Pinal Count y , with the remaining southernmost township located in neighboring Pima County. The current boundaries of the nonattainment and unclassified areas are codified at 40 CFR 81.303 and are defined by the following complete townships:
T ab le 1.1 - Study Area Definition S an Manuel Area Descrip tion T 8S , R16E T 8S , R17E T 8S , R18E T 9S , R15E T 9S , R16E T 9S , R17E T 9S , R18E T 10S , R15E T 10S , R16E T 10S , R17E T 11S , R16E T 10S , R18E T 11S , R17E T 12S , R16E T 12S , R17E Does Not Meet Primary S tan d ard s X X X X X X X X X X X X X X X Can n ot Be Classif ied
T he relationship between major SO2 point sources and ambient air quality is relatively welldefined. Emissions inventories demonstrate that the BHP Copper (formerly M a gm a Copper Comp any ) San M anuel smelter comprises 99 percent of total SO2 emission in the nonattainment area (See Chapter 4). The primary copper smelter is located near the town of San M anuel, Pinal Count y , Arizona; at latitude 32E36'58" N and longitude 110E37'19" W, at an elevation of 3,208 feet A s required by t he Clean Air A c t above mean sea level (See Figure 1.2, on the next page). (CAA), Arizona submitted a State Implementation Plan (SIP) for all major sources in the state in 1972. The portion of the SIP pertaining to attainment and maintenance of the NAAQS for SO2 did 4
not sufficiently define emissions limitations or require permanent control of emissions for existing cop p er smelters and was, therefore, disapproved on July 27, 1972 (37 FR 15081). On the same dat e, EPA proposed revised regulations for control of sulfur oxides emitted by all existing smelters in Ariz o n a (37 FR 15096). These regulations were never finalized due to issues regarding the adequacy
of the air quality data used to develop the limits. EPA subsequently established an SO2 monitoring net work around each smelter (June 1973 - October 1974) to gather air quality data upon which to base emissions limitations. EPA and State efforts to develop comprehensive emissions limits continued through the 1970s. In 1977, the State developed rules for the use of Supplementary Control Systems (SCS), whereby , based on ambient monitoring data, the smelters could intermittently curtail emissions to meet the SO2 NAAQS. EPA disapproved this approach and required installation and operation of SO2 emissions controls at all times to adequately to meet the NAAQS. Consequently, on January 4, 1978, EPA published final emissions limits for the Arizona smelters based on the 1973-1974 air qualit y data and the use of a proportional rollback model (43 FR 755). These regulations specified an emission rate and appropriate compliance test methods for each smelter. The 1977 Clean Air Act Amendment s, however, modified smelter control requirements to allow the temporary use of SCS while the ultimate SO2 emission limits were developed and also allowed certain smelters additional t ime for emissions control technology to be installed. In response to this action, Arizona began develop ment of new regulations and on September 20, 1979, submitted M ult i-p oint Rollback (M PR) rules as a proposed revision to the Arizona SIP.3 T he use of M PR to establish emissions limits in the rules addressed the p r o blem of inherent ly variable SO2 emissions from smelting operations by correlatingthe frequency of emissions at various levels with the probability of violating the ambient standards. This technique, "rolled back" a yearly emission profile to a level protective of the standards. The new regulations also set requirement s for analyzing the impact of smelter SO2 fugitive emissions on ambient air quality and t he implementation of any necessary fugitive controls. The San M anuel area was subsequently classified by operation of law as nonattainment for the primary SO2 standards by EPA following t he enactment of the 1990 Clean Air Act Amendments. The nonattainment designation became effect ive on November 15, 1990. The M PR rules, which established stack emission limits for the smelters, were approved by EPA on January 14, 1983 (48 FR 1717). Following EPA's approval of the rule, a consent decree bet ween EPA, ADEQ and M agma Copper Company, now owned by BHP, (#CIV 87-106-TUCWBD, dated September 28, 1987) was agreed to and required implementation of improved control t echnology , including replacement of reverberatory furnaces with a flash furnace, installation of convert er secondary hoods for capture and venting of gases to the stack, and a double absorption acid p lant retrofit. These controls significantly reduced emissions and allowed the smelter to come into comp liance with the emissions limits in the M PR rules. The San M anuel smelter came into full comp liance with the M PR regulations in November 1988. Additional consent decree requirements t o install and operate fugitive capture systems on the new flash furnace, as well as the existing cop p er converters, also reduced smelter fugitive emissions. On April 3, 1986, BHP submitted to the State [Arizona Department of Health Services
Arizona Code of Rules and Regulations (ACRR): Rule (R)9-3-515 (recodified as Arizona Administrative Code (AAC) R18-2-
7 1 5 , Standards of Performance for Existing Primary Copper Smelters; Site-specific Requirements)
(ADHS)] a plan describing SO2 fugitive emission units, its evaluation, and a demonstration study, t o partially fulfill outstanding SIP commitments for analysis of fugitive emissions. The results of a fugitive SO2 emissions study of the launders (where slag and matte tapping operations occur) was submit t ed on November 18, 1989. A Differential SO2 Ambient Impact Assessment Report was comp let ed and submitted on January 28, 1993. Subsequently, on M arch 24, 1998, BHP was issued a Significant Permit Revision (Permit Number 1000681) that allowed the company to perform mult ip le equipment upgrades for certain smelter equipment. These upgrades were completed during a 45-day shutdown beginning in M ay 1999. Although the upgraded smelter was functionally ready t o operate at the end of June 1999, BHP made a decision to temporarily cease operations due to low cop p er prices. In 2001, BHP anticipated restarting smelting operations. However, since the smelter was shut down for more than two years, BHP was required to perform an air quality impact analysis p ursuant to Arizona Administrative Code (AAC) Title 18, Chapter 2, Article 4 (R18-2-411) prior t o resumption of operations and demonstrate that the startup would not cause or contribute to a violat ion of the national ambient air quality standards for SO2 .4 BHP conducted the ambient impact analy sis at much lower emissions limits than those stated in the M PR SIP rules. The demonstration analy z ed maximum actual stack and fugit ive emissions, in relation to resulting ambient concent rat ions. Based on this analysis, BHP applied for and received a permit revision in 2001 to incorp orat e these more stringent emission limits in the permit. A 2001 rulemaking revised R18-2715 to new incorporate the new emissions limits. The revisions further reduced the smelter's stack emissions limits and added new limits for converter roof fugitive emissions (See Appendix A). The new limits provide a considerable margin of safety to ensure protection of the SO2 NAAQS t hroughout t he maintenance period to year 2015, thus allowing the state to request the area be redesignat ed to attainment for SO2 . 1.3 1.3.1 Physi cal , Demographic, and Economic Description of the S an Manuel Area Climate and Physiography
Bot h desert terrain and mountain ranges are found within Pinal County's landscape. Elevat ions range from near 2,000 to more than 6,000 feet above sea level in the nonattainment area wit h the town of San M anuel situated at an elevation near 3,400 feet. This unique environment exp eriences both warm desert and cool alpine climates. In San M anuel, the hottest month of the y ear is July, when the average daily maximum temperature is 97o Fahrenheit (F). January is the coolest month with an average daily minimum temperature of 35o F. Precip it at ion generally occurs in two seasons. The wettest month in San M anuel is July when monsoonal thunderstorms produce an average monthly total of 2.67" (inches) of rain. Pacific wint er storms moving across the area in December produce an average of 1.51" monthly precipitation in the form of rain or snow. The driest month is June, with an average of 0.25" of rain. The average
See Appendix A for all pertinent sections of Arizona Administrative Code in this document.
y early precipitation is 14.59". 1.3.2 Population
San M anuel is located in the broad San Pedro River Valley of southeastern Pinal County. M ammot h and Oracle are located within a ten-mile radius. Florence, located in the central Pinal Count y , is the county seat. Alt hough the growth rate of the San M anuel census designated place (CDP) exceeded 25 p ercent during the 1970s, by 1990 it lost 30 percent more inhabitants than it gained during the 1970s.5 The 2000 Census showed that San M anuel grew at a rate of 9 percent during the 1990s. In comp arison, M ammot h continued to lose population during each of the three decades. The Oracle CDP gained more than 22 percent and 17 percent during the 1980s and 1990s, respectively. During the 1970s when rural counties outpaced the growth of urban counties in the U.S., Pinal County grew by more than 32 percent. The county's growth was 28 percent during the 1980s, but it sharply increased to 54 percent during the 1990s. The state grew at 40 percent during the 1990s. Decennial census data for San M anuel CDP, M ammot h, Oracle CDP, and Pinal County are shown in Table 1.2.
T ab le 1.2 - Decennial Census Population of San Manuel CDP, Mammoth, Oracle CDP, an d Pinal County: 1970-2000 Year S an Manuel CDP S an Manuel's decennial change Mammoth Mammoth' s decennial change Oracle CDP 7 Oracle' s decennial change P inal County 68, 579 90, 918 1, 953 Ap ril 1, 1970 4, 332 Ap ril 1, 1980 5, 443 25. 6% Ap ril 1, 1990 4, 009 -26. 3% Ap ril 1, 2000 4, 3756 9. 1%
1, 906 -2. 4% 2, 484
1, 845 -3. 2% 3, 043 22. 5% 116, 397
1, 762 -4. 5% 3, 563 17. 1% 179, 727
Census Designated Places (CDPs) are delineated for decennial censuses. CDPs are places that are not legally incorporated
an d represent the statistical counterparts of incorporated places. 6 The 2000 Census shows a population of 4,375 with 1,832 housing units of which 1,458 are occupied (20.4 percent vacant). The
n u mb er of occupied housing units equals the number of households residing in San Manuel with 3.0 persons per household. San Manuel has n o group quarters population. 7 No data available for 1970.
Table 1.2 - Decennial Census Population of San Manuel CDP, Mammoth, Oracle CDP, an d Pinal County: 1970-2000 Year P inal' s decennial change
So u rce: U.S. Bureau of the Census, decennial census counts.
Ap ril 1, 1970
Ap ril 1, 1980
Ap ril 1, 1990
Ap ril 1, 2000
Arizona Department of Economic Security (DES) population estimates are the official st at i s t i c s for the State and differ slightly from the 2000 Census population counts. Table 1.3 p ort ray s the DES projected growth of San M anuel CDP, M ammot h, Oracle CDP, and Pinal County in five-year increments from 2000 to 2015. Projected populations by the DES for Pinal County for 2000 is ten percent lower than the 2000 Census population. The Oracle CDP and M ammot h, however, have DES projected populations for 2000 that are higher than the 2000 Census populations by about 37 percent and 15 percent, respectively. According to the Arizona Department of Economic Security, Oracle CDP and M ammot h are p r o ject ed to grow about 44 percent and 6 p ercent , respectively, between 2000 and 2015. San M anuel CDP is projected to grow 7 percent during this same time period.
T ab le 1.3 - Population Projections for San Manuel CDP, Mammoth, Oracle CDP, and, Pin al County: 2000-2015 Year S an Manuel CDPP Mammoth Oracle CDP P inal County Ju ly 1, 2000 4, 392 2, 020 4, 909 161, 630 Ju ly 1, 2005 4, 503 2, 066 5, 687 181, 487 Ju ly 1, 2010 4, 604 2, 108 6, 402 199, 715 Ju ly 1, 2015 4, 698 2, 146 7, 048 216, 215
So u rce: Arizona Department of Economic Security, August 1, 1997.
1.3.3 Economy Pinal County was created in 1875 from portions of M aricop a and Pima Counties by the eight h territorial legislature. The county covers 5,371 square miles. The State of Arizona is the count y 's largest landholder with 35.3 percent. Individual and corporate ownership accounts for 25.7 p ercent of the land area. Indian reservations cover 20.3 percent; the US Forest Service and Bureau of Land M anagement hold 17.5 percent; and other public lands comprise the remaining 1.2 percent. Pinal County is a great source of mineral wealth. Silver originally attracted settlers to the area, but as the silver resources were depleted, copper was mined. In 1944, M a gm a Copper Company 10
p urchased existing mining claims in the eastern portion of the county and launched a development and exploration program. In 1996, M agma was purchased by BHP Copper, which in 2001 became known as BHP Billiton. Accordingto the most recent publication of County Business Patterns, economic sectors with more than 3,000 employees in Pinal County include: mining (3,214), manufacturing (4,151), retail t rade (4,532), health care and social as s i s t a n c e (3,022), and accommodation and food services (3,653).8 Data exclude agricultural production employees and most government employees, as well as self-employed, employees of private households, and railroad employees. T able 1.4 contains employment, expressed as percentages of total nonfarm employees, for Pinal County for 1994, 1997, and 2000. This table also includes labor force data. Table 1.4 is included to demonstrate the decline in mining and quarrying activities and the relatively consistent p rop ort ions of the other economic activities in the county. T he major local emp l oy er in San M anuel has been BHP Copper Smelting and Refining Comp any that operated underground and open pit copper mines and associated activities. However, t he operations were temporarily stopped in June of 1999. According to Arizona Department of Commerce, smaller mines and quarries, as well as cattle ranches, in this area provide employment opportunities. Table 1.5 shows a selected time series of civilian labor force data for San M anuel.
U.S. Department of Commerce, U.S. Census Bureau, Table 6, "Counties_Employees, Payroll, and Establishments by Industry:
1 9 9 9 , " issued April 2001. Data represent the number of employees for the week including March 12.
T ab le 1.4 - EconomicActivity in Pinal County by Number of Employees: 1994, 1997, and 2000 E con omic activity9 C ivilian labor force Unemployment Unemployment rate T otal employment Non-farm employment Mining and quarrying C onstruction Manufacturing T CP U T rade F IR E S ervices and misc. Government 1994 48, 950 2, 800 5. 7% 46, 150 36, 100 10. 8% 3. 3% 11. 9% 1. 9% 19. 9% 1. 7% 16. 1% 33. 2% 1997 54, 450 2, 725 5. 0% 51, 725 39, 775 13. 1% 4. 5% 7. 6% 2. 0% 19. 0% 2. 1% 18. 1% 2000 59, 425 2, 475 4. 2% 56, 950 36, 525 3. 7% 3. 8% 8. 6% 2. 3% 21. 0% 2. 3% 20. 3%
So u rce: Derived from Arizona Department of Economic Security data. Totals may not add to 100 percent.
T ab le 1.5 - Civilian Labor Force Data for San Manuel CDP: Selected Years Year C ivilian Labor Force Number Unemployed Unemployment Rate 1990 1, 704 77 4. 5% 1995 1, 943 47 1998 2, 113 44 1999 2, 252 63 2000 2, 225 47
So u rce: Arizona Department of Economic Security. Data represent annual averages. Numbers for 1999 and 2000 are preliminary.
1.4 General S IP Approach In November 1990, the United States Congress enacted a series of amendments to the Clean Air Act (CAA) intended to improve air quality across the nation. One of the primary goals of this
9 TC PU = Transportation, Communication, and Public Utilities; FIRE = Finance, Insurance, and Real Estate.
comp rehensive revision to the CAA was to expand and clarify the planning provisions for those areas not currently meeting the NAAQS. The CAA as amended identifies sp e cific emission reduct ion goals, requires both a demonstration of reasonable further progress and attainment, and incorp orat es more stringent sanctions for failure to attain or to meet interim milestones. CAA, Title I, Part A, and Title I Part D, Subparts 1 and 5 are applicable to this SIP and maint enance plan. Sections 172, 175(A ) , 191, and 192, in the following section, set forth the following requirements for SO2 nonattainment areas. 1.4.1 CAA Section 172(c), Nonattainment Plan Provisions
172(c)(1) - In General: "...implementation of all reasonably availabl e con t rol me asure s (RACM) as expeditiously as practicable (including such reductions in emissions for existing sources in the area as may be obtained through the adoption, at a minimum, of re asonabl y available control technology (RACT)) and provide for attainment of the national pri mary ambient air quality standards." BHP Copper, the primary source of SO2 emissions in the San M anuel nonattainment area, succeeded in implementing RACM /RACT at the smelter sufficient to attain the NAAQS for SO2 and went beyond the required technology to increase the facility's efficiency in capturing and treating SO2 . RACT for SO2 emission controls for a flash smelting furnace include: 1. 2. 3. 4. 5. Dust Collection Equipment (removes dust for better gas treatment), Wet Scrubber, M inimiz at ion of Leaks, Hooding and venting of gases to the stack, and Contact Sulfuric Acid Plant.
Chapter 6 contains further explanation of applicable RACM /RACT for the BHP smelting facilit y and other SO2 point sources in the nonattainment area. 172(c)(2) - Reasonable Further Progress (RFP): "...plan provisions shall demonstrate re asonabl e further progress such that annual incremental reductions in emissions ensure attai nme nt of the national ambient air quality standards by the applicable date." T his submittal demonstrates that the San M anuel nonattainment area has obtained and will maint ain the SO2 NAAQS with current control measures (See Chapter 6). 172(c)(3) - Inventory: "...the plan shall include a comprehensive inventory of actual e mi ssi ons from all sources of relevant pollutant(s)."
ADEQ maintains a historical and current database of actual emissions from State-permitted p oint and area sources. The Pinal County Air Quality Control District maintains a similar database of actual emissions from County-permitted sources. All non-permitted source emissions data (ie: mobile sources) is obtained from EPA's national emissions inventory.1 0 Base-year (1998) emissions and projected 2015 emissions are contained in Chapter 3 4. 172(c)(5) - Permits for New and Modified Major S tati onary S ource s: "...the plan shall re qui re permits for the construction and operation of new and modified major stationary source s throughout the nonattainment area." All new sources and modifications to existing sources in Arizona are subject to state requirement s for preconstruction review and permitting pursuant to AAC, Title 18, Chapter 2, Art icles 3 and 4. All new major sources and major modifications to existing major sources in Arizona are subject to the New Source Review (NSR) provisions of these rules or Prevention of Significant Det eriorat ion (PSD) for maintenance areas. The State NSR program was conditionally approved by EPA in 1992, and is pending final approval. It should be noted that ADEQ currently has full ap p roval of its Title V permit program. 172(c)(6) - Other Measures: "...the Plan shall incl u de e n f orce abl e emissions l i mi tati ons and such other control measures, means or techniques, as well as schedule and ti me tabl e s for compliance, as may be necessary or appropriate to provide for attainment of such standard in such area by the applicable attainment date." AAC R18-2-715, Standards of Performance Primary Copper Smelters, Site Specific Requirement s, contains the required annual average emission limitations and number of three-hour average emission limits for the BHP smelter.1 1 AAC R18-715.01 (Standards of Performance for Exist ing Primary Copper Smelters; Compliance and M onit oring), set forth the compliance date of January 14, 1986, for monitoring, calibration, measurement system performance requirements, record keep ing, bypass operation, and iss u a n ce of notices of violation. Details regarding emissions limit at ions and control measures for all SO2 sources in the nonattainment area may be found in Chap t er 4. 172(c)(7) - Compliance with S e cti on 110(a)(2): "...the Plan shall be in compliance with S e cti on 110 (a)(2) (Implementation Plans) of CAA." Sect ion 110(a)(2)(A) of CAA requires that states provide for enforceable emission limitations
10 AIRData provides access to air pollution data for the entire United States and can be found at
h ttp ://www. ep a. g o v /air/d ata/in d ex . h tml 11 Standards of Performance for Existing Primary Copper Smelters; Site-specific Requirements, AAC R18-2-515, renumbered
and other control measures, means, or techniques, as well as schedules for compliance. Chapter 4 includes the list of control measures utilized to bringthis area into attainment and future maintenance of the SO2 NAAQS. Sect ion 110(a)(2)(B) of CAA requires that states provide for establishment and operation of appropriate devices, met h o d s, systems, and procedures necessary to monitor, compile, and analy z e data on ambient air quality. Under A D E Q 's air quality assessment program, ambient monit oring networks for air quality are established to sample pollution in a variety of representative set t ings, to assess the health and welfare impacts and to assist in determining air pollution sources. T he monitoring sites are combined into networks, operated by a number of government agencies and regulat ed companies. Each network is comprised of one or more monitoring sites, whose data are comp ared to the NAAQS, as well as statistically analyzed in a variety of ways. The agency or comp any operating a monitoring network also tracks data recovery, quality control, and quality assurance parameters for the instruments operated at their various sites. The collected data are summarized into the appropriate quarterly or annual averages. The samp lers are certified by Federal Reference or Equivalent M et hods. Regular checks of the stability, rep roducibilit y , precision, and accuracy of the samplers and laboratory procedures are conducted by eit her the agency or company network operators. The protocol for SO2 monitoring used by the St at e, local agencies, and companies was established by EPA in the following sections of the Code of Federal Regulations (CFR): 40 CFR Part 50, Appendix A, Reference M et hod for the Determination of Sulfur Dioxide in the Atmosphere; 2. 40 CFR Part 53, Subpart B, Procedures for Testing Performance Characteristics of Aut omat ed M et hods for SO2 , CO, O3 , and NO2 ; and 40 CFR Part 58, Subpart A, B, and C, Ambient Air Quality Surveillance. 3. (Chap t er 2 includes monitoring network information and data for the San M anuel area.) Sect ion 110 (a)(2)(C), Section 110 (a)(2)(E), Section 110 (a)(2)(F), and Section 110 (a)(2)(L) of CAA require states to have permitting, compliance, and source reporting authority. Arizona Revised Statutes (ARS) � 49-402 establishes ADEQ's permitting and enforcement authority. As aut horiz ed under ARS 49-402, ADEQ retains adequate funding and employs adequate personnel to administ er the air quality program. Appendix A includes the organization chart for ADEQ's Air Qualit y Division. Under ADEQ's air permits program, stationary sources that emit regulated pollutants are required to obtain a permit before constructing, changing, replacing, or operating any equipment or p rocess which may cause air pollution. This includes equipment designed to reduce air pollution. Permit s are also required if an existing busines s t h a t causes air pollution transfers ownership, relocat es, or otherwise changes operations. Additionally, ADEQ is responsible for assessing annual fees to recoup the costs of administering a permit pursuant to AAC R18-2-326. AAC R18-2-327 requires that any source subject to a permit must complete and submit to 15 1.
t he Director their responses to an annual emissions inventory questionnaire. A current air pollutant emissions inventory of both permitted and non-permitted sources within the state is necessary to p rop erly evaluate the air quality program effectiveness, as well as determine appropriate emission fees for major sources. This inventory encompasses those sources under state jurisdiction emitting 1 ton per year or more of any individual regulated air pollutant, or 2.5 tons per year (tpy) or more of any combination of regulated air pollutants.1 2 ADEQ is responsible for the preparation and submit t al of an emissions inventory report to EPA for major sources and emission points prescribed in 40 CFR 51.322, and for sources that require a permit under ARS �49-426 for criteria pollutants. Under ADEQ's air quality compliance program, scheduled and unscheduled inspections are conduct ed at the major sources annually. ADEQ's Air Compliance Section also implements comp liance assistance initiatives to address non-compliance issues (i.e., seminars and workshops for t he regulated community explaining the general permit requirements, individual inspections of all p ort able sources within a geographical area, mailings, etc.). In addition, compliance initiatives are develop ed to address upcoming or future requirements (i.e., new general permits) and include such act ions as training for inspectors; development of checklists and other inspection tools for insp ect ors; public education works h o p s ; targeted inspections; mailings, etc. ADEQ's Air Comp liance Section also has an internal performance measure to respond to all complaints as soon as possible, but within five working days. Section 110(a)(2)(G) of CAA requires that states provide for authority to establish emergency powers and authority and contingency measures to prevent imminent endangerment. AAC R18-2-220 prescribes t h e procedures the Director of ADEQ shall implement in order to p revent the occurrence of ambient air pollution concentrations which would cause significant harm t o the public health. As authorized by ARS �49-426.07, ADEQ may seek injunctive relief upon receip t of evidence that a source or combination of sources is presenting an imminent and substantial endangerment to public health or the environment. 172(c)(8) - Equivalent Techniques: "...the Plan may use equivalent techniques such as e qu i va l e nt modeling, emission inventory, and planning procedures allowed by the admi ni strator, upon application by any state." M ult i-Point Rollback modeling was used with EPA's concurrence to establish emissions limit s for the BHP Copper smelter and updated as part of the current SIP process. M odeling for t he fugitive emissions study at this facility was conducted with models from EPA's "Guideline on Air Quality M odels." 172(c)(9) - Contingency Measures: "...the Plan shall provide for the implementation
12 "Regulated air pollutant" is defined in AAC R18-2-101 as any of the following: (a) Any conventional air pollutant as defined
in ARS �49-401.01; (b) Nitrogen oxides and volatile organic compounds; (c) Any air contaminant that is subject to a standard contained in Article 9 of Chapter 2; (d) Any hazardous air pollutant as defined in ARS �49-401.01; (e) Any Class I or II substance listed in Section 602 of th e Act.
of specific measures to take effect without further action by the state or the Administrator i n the event the area fails to make reasonable further progress (RFP) or to attai n the pri mary national ambient air quality standards (NAAQS )." As noted in 172(c)(2) above, this s u b m it t al includes monitoring data and source permit informat ion that demonstrate that t h e ap p licable area has obtained, and will maintain, the SO2 NAAQS with control measures currently fully implemented. As such, the RFP requirement is met. 1.4.2 CAA Section 175(A) - M aint enance Plans
175(A)(a) - Plan Revisions: "...each state which submits a request for redesignation of a nonattainment area shall also submit a revision of the applicable S IP to provide for the mai nte nance of the NAAQS for at least ten years after the redesignation." As documented in Chapter 7, this submittal shows attainment through 2015. 1 7 5 ( A) ( b) - S ubse que nt Plan Revisions: "...eight years after redesignation as an attai nme nt area, the S tate shall submit an additional revision of the applicable S IP for mai ntai ni ng the NAAQS for 10 years after the expiration of the 10-year period referred to i n subsection (a)." ADEQ commits to submit an additional SIP revision eight years after redesignation. 175(A)(c) - Nonattainment Requirements Applicable Pending Plan Approval: "...until such plan revision i s approved and an area is redesignated as attainment for any area de si gnate d nonattainment, the requirements of this part shall continue in force and effect." ADEQ commits to keeping all applicable measures in place. 175(A)(d) - Contingency Provisions: "...each plan revis i o n submitted under this se cti on shall contain such contingency provisions to assure that the S tate will promptly corre ct any violation of the standard which occurs after the redesignation of the area as an attai nme nt area. S uch provisions shall include a requirement that the S tate will implement al l measures with respect to the control of the air pollutant concerned before redesignation." ADEQ commits to implementing all identified measures as necessary (See Chapter 7).
CAA Section 191 and 192 - Plan Submission and Attainment Dates
T his document fulfills all outstanding implementation plan requirements for the San M anuel SO2 nonattainment area. With the submittal of this SIP and M aint enance Plan, ADEQ requests redesignat ion of the San M anuel nonattainment area to attainment. 1.4.4 Conformity Provisions
Sect ion 176(c)(1)(A) of CAA requires SIPs to contain information regarding the State's com p l i a n c e with conformity requirements. As stated in 40 CFR 93.153(a), "Conformity det erminat ions for Federal actions related to transportation plans, programs and projects developed, funded, or approved under title 23 U.S.C. or the Federal Transit Act (40 U.S.C. 1601 et seq.) must meet the procedures and criteria of 40 CFR part 51, subpart T, in lieu of the procedures set for in t his subpart." 40 CFR 93.103(b) waives transportation conformity for SO2 nonattainment areas, but general conformity for the San M anuel, Pinal County area must still be addressed to assure SO2 emissions from any Federal actions or plans do not exceed the rates outlined in 40 CFR 93.153(b)(1) for nonat t a i nment areas or 40 CFR 93.153(b)(2) for maintenance areas. Criteria for making det erminat ions and provisions for general conformity as outlined in 40 CFR 93.153 can be located in R18-2-1438 of the Arizona Administrative Code. There are no federal plans or actions affecting air quality currently in the San M anuel, Pinal County area, nor are any foreseen through the year 2015.
T he provisions of 40 CFR 60 Subpart P (��60.160 - 60.166) Standards of Performance for Primary Copper Smelters are applicable to dryer, roaster, smelting furnace, and copper converter equip ment in primary copper smelters.1 3 Any facility that commences construction or modification aft er October 16, 1974, is subject to the requirements of this subpart. The San M anuel smelter was modified in 1988 when the Outokumpu flash furnace, converter secondary hoods, retrofit of the acid p lant , and a flux processing unit were installed, per the 1987 Consent Decree, and again in 1992 when t he #3 converter was rep laced. ADEQ compliance, permit, monitoring, technical, and corresp ondence files indicate that the facility has complied with all the requirements of this subpart.
Source: 41 FR 2338, Jan. 15, 1976, unless otherwise noted.
M onit oring began in the San M anuel area as early as 1969 by the State of Arizona.1 4 BHP began continuous ambient SO2 air quality monitoring in the San M anuel area in 1973. An extensive monit oring network was established wit h s ufficient spatial and temporal coverage to comp rehensively evaluate the ambient impact of smelter emissions. M ore than eighteen stationary and mobile monitoring sites were established throughout the area with as many as ten monitors op erat ing concurrently (See Table 3.1 and Figure 3.1).1 5 This ambient SO2 network, comprised of EPA, state, and BHP monitors, was developed as the result of extensive efforts to identify maximum ambient impact areas usingdiffusion modeling, monitored atmospheric dispersion parameters, citizen observat ions, and ambient SO2 monitoring. Stanford Research Institute (SRI), a facility contractor, was engaged to study the effects of SO2 emissions from the San M anuel smelter on the surrounding environment. Criteria for det ermining ambient SO2 and meteorological monitoring locations under SRI's recommendation, " Environment al Studies at San M anuel, 1972," included consideration of public health, areas of frequent high SO2 concentrations and relatively high long-term average concentrations. A gaussian diffusion model and meteorological records from the Tucson National Weather Service were emp loy ed in the study to predict SO2 dispersion patterns in the San M anuel area. In addition, fortyseven sulfation plate monitoring sites were utilized to characterize ambient SO2 over 500 square miles surrounding the area. The studies contributed to the subsequent expansion of the monitoring network including inst allat ion of seven of t h e initial stationary sites (M ammot h Courthouse, M inesit e, Oracle Court house, Golf Course, Peppersauce, and Redington) and implementation of a mobile analyzer. Inst allat ion of additional meteorological instrumentation at the network sites, measuring wind speed and direction, temperature, and humidity parameters helped to further define airflow and pollutant t ransp ort in the region. Utilization of mobile monitors allowed evaluation and verification of ambient SO2 concentrations over a greater area. Numerous sites were monitored and subsequently relocated under the direction of stat e met eorologist s when no significant impacts were observed. All monit oring for SO2 was performed with guidance and dispersion modeling analysis from the Arizona Dep art ment of Health Services, Bureau of Air Quality Control. The monitoring network was also developed in accordance with Supplementary Control Sy st ems (SCS). Prior to implementation of continuous control technology, SCS utilized analysis of at mosp heric conditions and monitored ambient concentrations to vary the rate of smelter emissions t o avoid any exceedance of the NAAQS. In 1977, the state adopted rules that codified requirements for concurrent operation of at least eight ambient monitors, including a mobile monitor placed at p oint s representative of observed maximum concentrations. Relocation of a stationary monitor was
14 Sulfur Dioxide Monitoring Network Study, Arizona State Department of Health, Environmental Health Services, Division of Air Po llu tio n Control, 1969. 15 Protocols for SO2 monitoring established by EPA are found in 40 CFR Part 50, Appendix A, Reference Method for the
Deter min a tio n of Sulfur Dioxide in the Atmosphere, Part 58, Subpart B, �58.14, Special Purpose Monitors, Subpart C, �58.20, State and Local Air Monitoring Stations, Air Quality Surveillance: Plan Content, and Subpart D, �58.30, National Air Monitoring Stations (NAMS).
allowed only when: 1. 2. T here were no ambient SO2 violations recorded; No SCS curtailment actions were implemented due to data recorded at that monitor;
T ab le 3.1 - Ambient Monitoring Network Mon itor Site T own site Hosp ital L DS Church 1 6 Dorm Site E lks In d u strial Hygiene Up p er Shopping Center Golf Course T railer Park Min esite Mercer Ranch E ast Peppersauce Wash Oracle Courthouse Oracle Holy Cross Can yon 3-C Ranch Mammoth Courthouse Mammoth Aravaipa Can yon Red in gton Mob ile I E PA1 7
Period of Operation 1969-1974 and 1979-present 1987-present 1975-1999 1978-present 1987-1994 1981 1975-1978 1974-1997 1974-1975 1974-1994 1979-1980 1974-1978 1975-1994 1978-1979 1981-1982 and 1987-1994 1974-1987 1980-1981 1976-1985 1977-1978 1973-1974
The LDS Church monitor was removed in June 1999, due to the temporary closure of the BHP smelter. ADEQ commits to
rees tab lis h in g this monitoring station by February 2002. 17 Three EPA established monitoring sites were operated during this period.
SOUR C E: Locati o n s c o m p i l e d from BHP San Manuel operations and ADEQ archives. Man u al notes eleven experimental mobile monitoring locations to date.
The 1977/1978 Operations and Mantenance
3. 4.
T he foregoing conditions were due to implementation of improved emissions control t echniques or other permanent modifications; and A new site was shown to be more representative of the ambient air quality of the area.
Hist oric ambient SO2 monitoring site locations and periods of operation are provided in T able 3.1, and Figure 3.1 and 3.2. Furt her refinement of the monitoring network was required by the adoption of the M PR rule that established stack emissions limits for the smelter in 1979 based on permanent controls. Placement of additional monitors were established with EPA to further evaluate ambient imp act s. Following BHP's compliance with emissions limits as defined in AAC R18-2-715(F), and based on continuous emissions control technology, the number of permanent monitors was gradually reduced to the current network of four. These are all high impact ambient monitor sites found to be representative of air quality for the area. These monitoring site decisions were made by ADEQ and BHP concurrence and in accordance with EPA guidance.
Curre nt S ampl e r Type and S i ti ng T he three monitoring units operated by BHP are Thermo Electron pulsed fluorescent (T ECO) M odel 40 SO2 analyzers. All of these SO2 analyzers are interfaced to BHP's data acquisit ion system by telemetry. The TECO analyzers measure in the 0-2 ppm range. Redundant recording systems are operated for all of the BHP analyzers. The samplers are connect ed to strip chart recorders for backup and analyzed by planimeter as necessary for validat ion of recorded concentrations. The ADEQ SO2 analyzer is also a TECO analyzer, measuring in the 0-2 ppm range (Figure 3.1 illustrates the current monitor locations and p roximit y to the BHP smelter). The BHP and ADEQ monitors are operated and maintained in accordance with federal regulations as described in 40 CFR parts 58.13 and 58.22 as well as Ap p endices A and E of part 58. 3.1
Table 3.2 - Current Monitoring Network Un it1 8 LDS Church T ownsite1 9 L ocation 1. 75 miles southwest of BHP 1. 24 miles southwest of BHP E levation (feet) 3570 3480 Op erator ADEQ B HP
The Dorm Site and Hospital monitors are primarily fugitive emissions impact sites. Townsite and the LDS site are primarily
s tack impact sites. 19 The location of the Townsite monitor remains the same as in 1974. This monitor was the "limiting site" for the original MPR
an aly s is ("Ultimate Sulfur Dioxide Limits for Arizona Copper Smelters," Moyers and Peterson, September 14, 1979).
Dorm Site2 0 Hospital2 0
0. 7 miles northwest of BHP 0. 5 miles southwest of BHP
3400 3440
EPA required monitoring site per 1987 consent decree.
Ambi e nt Data Analysis A review of the SO2 monitoring data in the San M anuel nonattainment area verifies that: 1. 2. T here have been no recorded exceedances of the annual NAAQS for SO2 since 1974 and annual averages are generally 17.5 percent of the NAAQS; T here have been no recorded exceedances of the 24-hour NAAQS for SO2 since 1994 and maximum 24-hour average SO2 levels are generally 57 percent of the NAAQS; and, T here have been no recorded exceedances of the 3-hour NAAQS for SO2 since 1996 and maximum 3-hour averages are generally below 50 percent of the NAAQS.
T he nonattainment area has recorded more than eight current, consecutive quarters of quality assured, violation-free data from M ay 1997 through April, 1999.2 1 Data for the current monitoring net work is presented in Table 3.3, on the following pages.
Table 3.3 - SO2 Ambient Air Q u ality Monitoring Data (Fg/m3) Year An n u al Ave. 24Hou r Max 3-Hou r Max Nu mb er of Exceedances An n u al LDS Church 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 1989 1988 9 8 8 11 8 10 16 10 3 13 21 13 65 102 60 338 55 466* 94 121 367 139 267 125 220 707 291 1758* 362 720 721 519 1242 1053 631 793 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 6121 8494 8626 8183 8491 7857 8696 7794 8091 8668 8434 7944 24-h r. 3-hr. No. of 1-hr. S amp les
The two year period of record prior to the temporary cessation of smelter operations.
Table 3.3 - SO2 Ambient Air Q u ality Monitoring Data (Fg/m3) Year An n u al Ave. 42 44 24Hou r Max 191 282 3-Hou r Max 866 1499 Nu mb er of Exceedances An n u al 0 0 L DS Church con't 1985 1984 1983 1982 1981 1980 1979 1978 1977 1976 1975 56 41 34 47 66 32 58 53 58 42 43 388 236 224 303 284 295 524 509 435 471 563 1601 1185 1243 1064 1602 1953 2024 2476 1820 3117 3517 0 0 0 0 0 0 0 0 0 0 0 T own site 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 1989 1988 1987 4 8 33 18 11 15 28 26 18 20 42 25 51 69 105 95 167 71 121 166 197 180 222 272 167 276 290 570 374 1068 372 410 919 923 1064 1257 1294 1062 999 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 N/A 8656 8725 8765 8753 8740 8751 8773 8752 8746 8744 8771 8723 1 0 0 0 0 0 1 1 1 1 1 3 0 0 0 1 2 5 2 2 2 1 8667 8704 8412 8058 8130 8227 7403 6733 7308 8002 3880 24-h r. 0 0 3-hr. 0 1 No. of 1-hr. S amp les 8737 8449
1987 1986
Table 3.3 - SO2 Ambient Air Q u ality Monitoring Data (Fg/m3) Year An n u al Ave. 57 61 24Hou r Max 291 311 3-Hou r Max 1772 1514 Nu mb er of Exceedances An n u al 0 0 T own site Con't 1984 1983 1982 1981 1980 1979 50 49 59 42 32 73 337 264 364 312 273 611 1224 1484 1265 1641 1283 3014 0 0 0 0 0 0 Dorm Site 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 1989 1988 1987 1986 1985 1984 1983 1982 4 8 11 15 16 13 29 32 22 16 39 32 56 59 67 58 51 73 54 135 75 101 96 113 172 189 246 96 359 193 268 256 265 332 295 387 311 262 220 415 317 766 930 783 855 763 2704* 766 1179 971 1280 1353 1288 1701 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 4 N/A 8714 8751 8777 8746 6857 8751 8774 8750 8753 8749 8772 8734 8715 8699 8745 8711 8646 0 0 0 0 0 2 0 1 0 1 0 4 8712 8703 8680 8663 8677 8554 24-h r. 0 0 3-hr. 1 2 No. of 1-hr. S amp les 8719 8709
1986 1985
Table 3.3 - SO2 Ambient Air Q u ality Monitoring Data (Fg/m3) Year An n u al Ave. 74 58 24Hou r Max 275 340 3-Hou r Max 1656 2415 Nu mb er of Exceedances An n u al 0 0 Dorm Site con't 1979 1978 1999 1998 1997 74 N/A 8 11 32 412 254 214 154 208 1869 1085 433 712 705 0 N/A 0 0 0 Hosp ital 1995 1994 1993 1992 1991 1990 1989 1988 18 23 33 38 31 33 42 41 141 223 170 242 284 60 279 261 593 1632* 1248 1179 2175* 916 1881* 928 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 1 0 0 8752 8746 8752 8768 8751 8751 8747 8770 1017 1 0 0 0 0 4 0 0 0 0 8521 2181 N/A 8642 8742 24-h r. 0 0 3-hr. 1 4 No. of 1-hr. S amp les 8679 8534
1981 1980
1987 54 224 695 0 0 * - The exceedance was determined to be due to a process/equipment malfunction.
Emissions inventories from all sources in the San M anuel nonattainment area indicate that alt hough there are other sources of SO2 emissions, the BHP Copper smelter is the primary source for SO2 emissions and comprise more than 99 percent of total emissions in the area. Data shows that no other point, area or mobile sources have contributed, or contribute to the same levels of SO2 in t he San M anuel nonattainment area. Emissions units and rates, and derivation of mobile and area source emissions for the nonattainment area are described in Section 4.1 through Section 4.3 below.
S O 2 Point S ource s
T hree point sources are located within the San M anuel nonattainment area. Point source locat ions are illustrated in Figure 4.1, on the following page. The most current inventories for these sources are presented in Table 4.1.
T ab le 4.1 - SO2 Emissions for San Manuel Nonattainment Area - Point Sources S ou rce Name Oracle Compressor S tation B HP Copper smelting op eration s2 2 B HP Copper mining an d milling operations 24 Hr. (tpd) An n u al (tpy) 24 Hr. (tpd) An n u al (tpy) 24 Hr. (tpd) An n u al (tpy) 1997 0 0 32 11, 482 <1 <1 32 11, 482 1998 0 0 29 10, 409 <1 <1 29 10, 409 1999 0 0 30 3, 6222 3 <1 <1 30 3, 622
24 Hour Total (tpd): An n u al Total (tpy):
Oracle Compressor Station
T his source is a natural gas transport facility that utilizes a natural gas powered turbine to comp ress the natural gas for transmission through a pipeline. The facility did not operate from 1997 t hrough 1999. When operating, the Oracle Compressor Station is a very low contributor to ambient
24-hour inventories are a ton per day (tpd) average calculated by dividing the annual facility emissions by the number of
o p eratin g days for each year. 23 Smelting operations were temporarily suspended beginning May 1999.
SO2 levels with total permitted emissions from existing equipment limited to 0.6 tpy.
BHP Copper San M anuel Smelter
Smelt ing and refining of copper ore at BHP's primary copper smelter operations produces cop p er cathode and copper rod as well as byproducts of the smelting process (molybdenum concent rat e, sulphuric acid, and gold and silver) for sale to customers. M ore than 99 percent of all SO2 emissions in the nonattainment area are generated by this facility when it is operating. Based on 1998 emissions data, the majority of this facility's emissions are from the following stack and fugit ive units: flash furnace fugitive stack, acid plant II tail stack, acid plant III tail stack, converter secondary and flash emergency vent stack, concentrate dryer stack, and fugitive emissions from the convert er building roof vents. The maximum allowable annual average SO2 emission rate for stacks was reduced from 18,275 lbs/hr to 1,742 lbs/hr with recent revisions to AAC R18-2-715(F)(1) and (G). The revisions also limited fugitive emissions from the converter building roof vents to 715 lbs/hr. The combined limit for the stack and fugitive emissions units is currently 2,457 lbs/hr (10,762 t p y ). Permit #1000681 issued M arch 24, 1998, further limits SO2 emissions from the concentrate dry er to a maximum 2,073 tpy, based on a 12-month rolling monthly average. Additional de minimis units include emissions from the anode and utility vessel roof vent. Emissions from these units at 1998 operating levels were estimated to be 59 tpy. In addition, the p ermit limits sulfur content and usage rates for fuel used in all fuel burning equipment. Actual emissions from fuel burning equipment, are minimal, at less than 2.5 tpy. Emissions units and rates for the BHP smelter are detailed in Appendix B. 4.1.3 BHP Copper M ining and M illing Operations
T his source is a mining and copper ore processing facility where copper sulphide ore is p rep ared for smelting and refining at the BHP smelter. The primary source of emissions from these minimal SO2 sources are natural gas and diesel burning equipment that include concentrate dryers, generat ors, and boilers. Permits for the mine and mill require the use of low sulfur natural gas and p rop ane in the generators and limits the potential to emit (PTE) from all existing equipment to 0.38 t p y of SO2 . Actual emissions, are minimal, at 0.03 tpy.
Major Point S ource s within the 50 km Buffer Area
In addition to the sources located within the nonattainment area, there are several point sources within 50 kilometers of the San M anuel nonattainment area. There is no information to suggest that emissions from these sources have contributed t o the same levels of SO2 in the nonat t ainment area as are demonstrated by the BHP smelter or that emissions from these sources could cause violations in the San M anuel nonattainment area. Attainment year inventories are p rovided in Table 4.2.
T ab le 4.2 - SO2 Emissions within 50km of the San Manuel Nonattainment Area Poin t Sources S ou rce Name: APS (Red Rock)2 4 24 Hr. (tpd) An n u al (tpy) 24 Hr. (tpd) An n u al (tpy) T E P (North Loop)2 4 24 Hr. (tpd) An n u al (tpy) AS ARCO Hayden S melter2 5 24 Hr. (tpd) An n u al (tpy) 1997 <1 1 8 2, 597 N/A N/A 79 27, 533 87 30, 131 1998 <1 8 7 1, 731 0 0 66 22, 077 73 23, 816 1999 <1 8 9 2, 862 <1 <1 58 21, 081 67
T E P (Irvington)2 4
24 Hour Total (tpd): An n u al Total (tpy):
Arizona Public Service (APS) - Red Rock
T he APS Red Rock electric generating station operates two steam turbine units, two gas t urbine units, and associated auxiliary equipment. The source's permit limits SO2 emissions from combust ion of fuel in the existing equipment to 15,051 tpy. This station was formerly a "peaking" p lant providing increased electricity generation during periods of high demand. Commencement of full time operations began in 2000. 4.2.2 Tucson Electric Power Co. Irvington
Product ion of electricity at this generating station is accomplished by combustion of fuels in four steam turbine and three gas turbine units. The facility's operating permit limits allowable SO2 emissions from the existing equipment to 20,150 tpy . Actual emissions, however, are less than 3,000 tp y . 4.2.3 Tucson Electric Power Co. North Loop
Daily inventories for the electric facilities were calculated by dividing the annual emissions by the number of operating hours
fo r each year and multiplied by a factor of 24 to obtain the 24-hour value. These inventories are based on the conservative assumption of 24 h o u rs of operation for each calculated operating day. 25 24-hour inventories are a ton per day (tpd) average calculated by dividing the annual facility emissions by the number of
o p eratin g days for each year.
T he Tucson Electric Power Company North Loop station currently operates four simple cy cle combustion turbine generators for the production of electricity. The turbines are primarily used as "peaking" units and are only fired when electrical demand requires their use. The permit lists p ot ent ial to emit at 4,718 tons of SO2 per year. Actual emissions for this facility are minimal at less t han 1 tpy in 1999. 4.2.4 ASARCO Hayden Smelter
T he Hayden primary copper smelter operates a flash furnace, converters, and other auxiliary equip ment for smelting and refining of copper sulfide ore. The permit limits smelter process SO2 emissions to 41,702 tpy. Actual emissions, however, are less than 23,000 tpy. In addition, the p ermit limits sulfur content and usage rates for fuel used in all fuel burning equipment. The Hayden smelt er is located in the Hayden SO2 nonattainment area. A separate state implementation plan (SIP) is being developed for this area and ADEQ anticipates submittal of the SIP to EPA in 2002.
Are a, Mobile, and Total S ource s
Emissions for the nonattainment area were derived from EPA NET area and mobile source invent ories for Pinal County based on the assumption that area and mobile source emissions are p rop ort ionat e to population levels. The San M anuel SO2 nonattainment area population is estimated t o be seven percent of the Pinal County population based on the aggregate population centers of San M anuel CDP, M ammot h, and Oracle CDP. The remainder of the nonattainment area has a very low p op ulat ion density with low traffic levels and minimal commercial or industrial development. Data shows that there are no urban areas that might be significant area or mobile sources located within t he San M anuel nonattainment area as illustrated in Table 4.3. Area and mobile sources combined were less than one percent of the total emissions during the period of BHP smelter operations in 1997, 1998, and 1999.
T ab le 4.3 - SO2 Emissions for the San Manuel Nonattainment Area - All Sources Source Type:2 6 Area and Mob ile2 7 24 Hr. (tpd) An n u al (tpy) 24 Hr. (tpd) 1997 <1 83 32 1998 <1 84 29 1999 <1 86 30
Poin t
Area and mobile source estimates are based on EPA's AIRData for Pinal County. Point source estimates are based on
ADEQ annual emissions inventory data. 27 24-hour inventories are averages based on a 365 day distribution of emissions from these sources.
Table 4.3 - SO2 Emissions for the San Manuel Nonattainment Area - All Sources An n u al (tpy) 24 Hour Total (tpd): An n u al Total (tpy): 11, 482 32 10, 409 29 3, 622 30
4.4 4.4.1
Emi ssi ons Projections Point Source Projections
Ariz ona does not anticipate any substantial increase in existing point source emissions bet ween 1999 and 2015 for the nonattainment area. Should any growth occur due to construction of additional SO2 point sources, ADEQ's permit program limits all emissions as part of the const ruct ion of new point sources or the upgrading of existing sources. Projections for copper smelters are based on growth rates contained in the Western Regional Air Partnership (WRAP), Annex to the Report of the Grand Canyon Visibility Transport Commission, Oct ober 16, 2000. This report notes that downward pressure on copper prices resulting from int ernat ional competition have produced a consolidation of the copper industry in the Southwestern Unit ed States. Consequently, no expansion of the industry is expected though 2015. Emissions p roject ion estimates for electric utilities are based on an anticipated industry growth rate of 2.6 p ercent per year contained in the WRAP report. These estimates are predicated, in part, on existing cap acit y and future demand for generation. The remaining minor sources (Oracle Compressor Station, BHP M ine and M illing Op erat ions) have existing permits limiting their potential to emit to less than one tpy. Table 4.4 and T able 4.5 present projected emissions for point sources within the nonattainment area and major p oint sources within 50 km of the nonattainment boundary.
Table 4.4 - SO2 Emissions Projections for the San Manuel Nonattainment Area - Point S ou rces Source Name: Oracle Comp resso r Station 24 Hr. (tpd) An n u al (tp y) 1997 0 0 1998 0 0 1999 0 0 2005 <1 1 2010 <1 1 2015 <1 1
Table 4.4 - SO2 Emissions Projections for the San Manuel Nonattainment Area - Point S ou rces Source Name: B HP smelter2 8 ,2 9 B HP mine an d millin g op eration s 24 Hr. (tpd) An n u al (tp y) 24 Hr. (tpd) An n u al (tp y) 1997 32 11, 482 <1 <1 32 1998 29 10, 409 <1 <1 29 1999 30 3, 622 <1 <1 30 2005 30 10, 900 <1 <1 30 2010 30 10, 900 <1 <1 30 2015 30 10, 900 <1 <1 30
24 Hour Total (tpd): An n u al Total (tpy):
T ab le 4.5 - SO2 Projected Emissions within 50km of the San Manuel Nonattainment Area - Major Point Sources S ou rce Name: E lectric Utilities3
2015 14 5, 031 66 23, 000 80
24 Hr. (tpd) An n u al (tpy) 24 Hr. (tpd) An n u al (tpy)
2, 598 79 27, 533 87
1, 739 66 22, 077 73
2, 870 58 21, 081 67
3, 892 66 23, 000 76
4, 424 66 23, 000 78
AS ARCO Hayd en S melter3 1
24 Hour Total (tpd):
28 29
Projections for the BHP smelter assumes resumption of smelting operations. The annual number of operating days used to calculate the projected 24-hour inventories for 2005 through 2015 (annual
emis s io n s divided by the number of operating days) were based on average operating conditions. The average number of operating days for th e period 1997 through 1999 were assumed to represent typical operating rates. Projections for electric utilities are based on the assumption of continued full time operation of the APS (Red Rock) generating s tatio n and were calculated using emissions from the most recent year of full time operations at this facility (497 tons of SO2 emissions were reco rd ed in 2001, the first year of full time operations). 31 The annual number of operating days used to calculate the projected 24-hour inventories for 2005 through 2015 (annual 30
emis s io n s divided by the number of operating days) were based on average operating conditions. The average number of operating days for th e period 1997 through 1999 were assumed to represent typical operating rates.
An n u al Total (tpy):
23, 951
Area, M obile, and Total Source Projections
ADEQ projects emissions of SO2 from area and mobile sources to grow proportionately wit h the population of the nonattainment area. Appendix B describes the source category emissions p roject ions in greater detail. Table 4.6 presents projected area and mobile, and total source emissions for the San M anuel nonattainment area.
T ab le 4.6 - SO2 Emissions Projections for the San Manuel Nonattainment Area - All S ou rces Source Type: Area and Mob ile 24 Hr. (tpd) An n u al (tpy) 24 Hr. (tpd) An n u al (tpy) 24 Hour Total (tpd): An n u al Total (tpy): 1997 <1 83 32 11, 482 32 11, 565 1998 <1 84 29 10, 409 29 10, 493 1999 <1 86 30 3, 622 30 3, 708 2005 <1 94 30 10, 901 30 10, 995 2010 <1 101 30 10, 901 30 11, 002 2015 <1 107 30 10, 901 30
Poin t
At t ainment is demonstrated through the clean ambient air quality record of more than ten y ears and use of M ult i-p oint rollback (M PR) modeling. The improvement in air quality is due to cont inuous SO2 emissions control technologies implemented by the San M anuel smelter to comply wit h the SO2 emission limits regulations adopted for Arizona smelters in September 1979. M PR, which was approved by EPA in January 1983 as a modeling technique for Arizona smelters, was select ed as the most precise and reliable method for then determining contemporary and future stack SO2 emission limits. M PR is a proportional rollback technique founded on the assumption that smelter emissions and ambient concent r at ions are proportional for a given set of dispersion conditions. Thus, a reduct ion in emissions results in a comparable reduction in ambient concentrations. Based on this assump t ion, the appropriate level of emission reductions to protect the NAAQS can be achieved if emissions are reduced by the ratio of the corresponding ambient concentrations to the air quality st andard. The use of M PR addresses the high variabilit y of both smelter emissions patterns and met eorological conditions, in part, by rolling back an entire emissions curve rather than a single emissions measurement. A rollback fact o r is det e rmined by fitting a concentration frequency dist ribut ion (from observed data) to an appropriate functional curve and calculating an expected once p er year maximum (limiting) value. The rollback or reduction factor is defined as the ratio of the ambient standard to the limiting value. Rollback factors are calculated for all applicable NAAQS averaging periods. The largest calculated rollback factor is used to reduce each emiss i o n which occurred over the period of data accumulation (the emissions profile). The maximum rollback value is chosen to ensure that all primary and secondary standards are protected. In the case of the San M anuel smelter, the 3-hour standard was selected as the most conservative limiting standard which is also protective of the 24-hour and annual standards.3 2 Because hourly emissions were not available, the original M PR analysis used an estimate of hourly SO2 emiss ions over the course of a year, based on knowledge of smelter operations and emissions variability, to construct an emissions curve. The entire curve was then "rolled-back" and t he resultant distribution used directly to construct the original M PR cumulative occurrence and 3hour average emissions limits tables for stacks. Hourly ambient SO2 concentration data from the T ownsit e monitor (a stack impact site) for the period October 1973, through September 1974, were used and average emissions were calculated by sulfur balance.
De ri vati on of New Emissions Limits Based on EPA's approval as a model, ADEQ utilized M PR as a component of the current
A detailed discussion of Multi-point Rollback methodology is contained in Ultimate Sulfur Dioxide Emission Limits for Arizona
C o p p er Smelters, September, 1979.
at t ainment demonstration, BHP performed a further M PR analysis of stack and fugitive emissions and resultant ambient impacts based on current operating levels. This analysis utilized data from the t wo most recent years of operation (M ay 1997 through April 1999), and included cont inuous measurement dat a for stack and converter fugitive SO2 emissions and measured ambient concent rat ions. These data were used to establish new stack and converter fugitive emission limits in rule that will maintain emissions below attainment period levels (See Appendix A). The new SO2 limits for stack and fugitive emissions at the San M anuel smelter maintain the basic M PR principles. Namely, that smelter emissions and meteorological conditions, which influence the impact of those emissions on air quality, are two highly variable but independent p r o c e s s es, and that emissions limits can be set that assure a high probability of attaining t h e ap p licable ambient air quality standards. The new limits are in the same format as the original M PR t ables. However, the derivation of the new values differs from the original in two important aspects. First , the new limits are based on actual hourly SO2 measurements. Second, these emissions required no reduction for compliance with the SO2 air quality standards because those standards were met by a large margin during the two year period from which the emissions data were obtained (See S e cti on 3.1 and 3.2). Accordingly, the new M PR limits did not require the complexity of calculation and assump t ions as the original effort. 5.1.1 Stack Emissions Limits
T wo years of data, based on actual emissions measurements from M ay 1997 through April 1999, were used in the current analysis to determine new 3-hour average emissions limits for stacks. T he data for this period (17,520 hourly values) were ranked in descending numerical order. Each successive pair of ranked values were averaged to obtain a single representative profile consisting of 8,760 hourly values for the attainment period. Three-hour running averages were calculated creating a new database of 8,760 three-hour averages. As with the original M PR, the highest 26 percent or 2,240 hours of the resulting averages was then sorted into 24 categories of cumulative frequency of occurrence values identical to the occurrence limits in the original M PR tables (0 to 2,240). The emission limits were selected using the same conceptual method used in the original M PR where in each category of allowed emission occurrences, the lowest actual emissions value in that range was used to establish the new limits. For example, the n cumulative frequency of occurrence where n = 7 in the new M PR table for stack emission corresponds to the emissions value E where E = 5660. T he measured emissions values that occur in the frequency, where n = 7, are 5860, 5747, and 5660 (See Appendix C). The selection of the lowest measured emissions value in each frequency of occurrence mimics the selection of the lowest calculated values of the original M PR analysis, which were all below the emissions profile or curve. The annual average emissions limit for stacks was determined from the calculated numerical average of the combined hourly stack emission values (17,520 hourly values). 5.1.2 Fugitive Emissions Limits
T he previous M PR limit was based on ambient impacts from stack sources. A similar M PR analy sis was also performed for uncaptured converter fugitive emissions based on the proportional imp act s of these emissions on ambient concentrations at fugitive impact sites (See S e cti on 3.1 and 3.2). Two years of measured converter roof emissions from M ay 1997 though April 1999, were used to establish 3-hour average and annual emissions limits for this source. Details of the analysis are presented in Appendix C.
Emissions Reductions
T he current rollback reduced allowable annual average stack emissions from 18,275 to 1,742 p ounds per hour (lbs/hr). Fugitive SO2 emissions as measured from the converter roof were reduced from the previous permit limit of 1,115 lbs/hr to 715 lbs/hr. Overall, allowable emissions from stack and fugitive sources were reduced from 84,928 tpy to 10,762 tpy providing a reduction of 74,166 t p y (approximately 87 percent). This reduction is illustrated in Figure 5.1.
Figure 5.1 - Comparison of 1979 and 2001 MPR Limits3 3
Allowable 3-hour Average Emissions 80000
60000 Emissions (lbs/hr)
48 94 180 330 Cumulative Occurance
1979 MRP Stack Limit 2001 MPR Converter Roof Fugitive Limit
2001 MPR Stack Limit
T o ensure that the variety of possible meteorological conditions were represented over the analy sis period and that favorable atmospheric dispersion did not influence the impact of emissions on ambient concentrations, the variation of emissions and ambient concentrations were compared from 1995 through 1999. The upper distribution of short-term (1-hour) total smelter emissions and three-hour ambient SO2 concentrations from all ambient monitors were determined for each of the five years. Review of the data demonstrates that emissions levels are relatively consistent throughout the M PR study p eriod. The 99th percentile emissions values for the five year period differ by only 534 lbs/hr. The result ing annual values are presented in Figure 5.2. Emissions for the period preceding the 2001 M PR analysis were marginally higher than emissions recorded during the M PR study period. When adjust ed for the difference in emissions between the two time periods (increased by the ratio of the
Limits contained in AAC R18-2-715(F)(1) and (G).
earlier to later emissions); however, ambient concentrations from the current M PR period do not vary significantly, and are less than five percent higher than the actual measured concentrations. The adjust ed ambient values continue to demonstrate protection of the NAAQS. A five year period is c o n s i d ered to be long enough to experience potentially restrictive meteorological conditions . Nonet heless, Figure 5.2 shows that high concentrations varied little from year to year.
99th Percentile Total Emissions and Ambient Concentrations
5500 5000 600
Figure 5.2 - San Manuel Smelter
3500 3000
300 2500 2000 1500 1000 500 0 1995 1996 Emissions Townsite 1997 Year Hospital 1998 Dormsite LDS 1999 0 100
S me l te r Configuration
Smelt er configuration and in particular the location and height, of SO2 releases was a critical considerat ion in finding the San M anuel smelter in compliance with the original M PR limits and for t he current demonstration of attainment of the SO2 NAAQS. The original M PR limits for the San M anuel smelter were based on 1973-1974 records of SO2 emissions and ambient concentrations. The smelt er achieved compliance with M PR emission limits in 1987 and remained in compliance through shut down in 1999. Although the smelter underwent major modifications and emission reductions over the years, the locat i o n and heights of SO2 releases have changed only slightly. Basically, emissions can be grouped into two categories based on the height of release. Low level emissions at height s less than 200 feet include fugitive and dryer st a c k emissions. High level emissions are p redominant ly from the reverberatory and converter stacks which are over 500 feet and include minor emissions form the 250 foot acid tail gas stacks. Table 5.1 and Table 5.2 show the release height s and SO2 emissions for 1974 compared to the most recent years of operation 1997-1999. 44
Ambient Concentration - 3-hour (ug/m3)
Emissions - 1-hour (lbs/hr)
Tabl e 5.3 shows the distances of the individual emission points to the facility property boundary. T hus the ambient SO2 network established in the 1970's and refined in the 1980's, including ext ensive sampling and testing for fugitive SO2 impact sites, occurred at a time with quite consistent
T ab le 5.1 - San Manuel Smelter Configuration 1974 to Present E mission s S ou rce 1974 Heigh t (f t) Presen t Heigh t (f t) 1974 Process E mission S ou rce High Level R everberatory F urnace process gases C onverter process gases NA Present Process Emission S ou rce F lash furnace captured and vented fugitive gases C onverter secondary hood and flash emergency vent gases C onstructed in 1975; decommissioned May, 1996 C onstructed in 1975 (converted to double contact in 1987, upgraded in 1994) Constructed and upgraded in 1994 Concentrate dryer gases(constructed in 1987) C onverter gases not captured by primary or secondary hood systems
Reverb S tack Con verter S tack T ail I
T ail II
T ail III
250 L ow Level
Dryer Stack Con verter Fu gitives
144 106
NA Direct Converter fugitive gases
T ab le 5.2 - San Manuel Smelter SO2 Emissions 1974 to 1999 (tpy)
E mission s Source
1997 High Level
Attain men t Period Average3 5
Reverb eratory Stack Con verter Stack T ail II Stack T ail III Stack T all Stack Total
1, 690 2, 436 186 538 4,850 L ow Level
1, 612 2, 249 220 400 4, 481
519 969 69 101 1, 658
1, 620 2, 531 204 414 4, 768
Dryer Stack3 6 Fu gitive L ow Level Stack an d Fugitive Total
3, 494 3, 003 6, 497
3, 018 2,846 5, 864
593 1, 370 1, 963
2, 764
6, 083
High and Low Level T otal 94, 300 11, 347 10, 345 3, 620 10, 851
Th e original MPR analysis projected an hourly emissions rate of 94,242 pounds of sulfur dioxide per hour as the basis for the
"ro llb ack " for the San Manuel Smelter. This projection was based on sulfur balance data submitted by the facility and supports empirical ev id en ce that approximately thirty percent of the sulfur content in sulfide copper concentrate will be oxidized by an initial melting step such as occurs in reverberatory furnaces. Of the remaining 70%, it is estimated that the 1980 vintage primary hood system at the San Manuel s melter was, at best, sixty percent efficient in capturing converter gasses. Consequently, 42% of these emissions actually reported to the co n v erter stack. The remaining 28% was emitted as low-level fugitive emissions. 35 Valu es represent average emissions from 1997 through 1999. Because smelter operations were suspended in May 1999, emis s io n s for this year were estimated based on January through April operating levels to reflect a full year of emissions. 36 A recent permit revision limits dryer SO2 emissions to 2,073 tpy based on a twelve month rolling average.
T ab le 5.3 - Emissions Source Distance from Facility Boundary (feet) E mission s Source R everb Stack C onverter Stack Dryer Stack T ail I T ail II T ail III C onverter fugitives Distan ce to Property Line1974 1, 399 1, 955 NA NA NA NA 1, 735 Distan ce to Property LinePresen t 1, 399 1, 955 144 NA 2, 160 1, 744 1, 735
release geometry. This consistency of SO2 release locations continued through the 1990's t hereby providing assurance that the ambient SO2 monitoring network continues to represent the maximum impact of SO2 emissions from the San M anuel smelter. As demonstrated above, SO2 concent rat ions in the San M anuel nonattainment area have been shown to attain the NAAQS
6.0 CO NTRO L MEAS URES Because the BHP smelter is responsible for the majority of SO2 emissions in the area, the following attainment demonstration control measures relate specifically to BHP smelting operations. Ap p licable controls for other point sources in the San M anuel nonattainment area are discussed in Chap t er 4.0.
6.1 Background 37 Smelt ing operations at San M anuel began in 1956. By the late 1950s the facility operated three reverberat ory furnaces to process copper sulfide ore from nearby mines. Today the San M anuel p rimary copper smelter utilizes a flash smelting process and has a processing capacity of more than 25 percent of total U.S. smelting capacity. The processing of copper sulphide ore begins at the mine where ore is crushed and transported t o the San M anuel concentrator. At the concentrator facilities, the ore is ground at milling operations and processed by froth flotation to separate copper mineral from ore. Further processing at a moly bdenit e plant recovers a molybdenum disulphide concentrate from the bulk concentrate, a major by p roduct of the San M anuel operations. Concentrates from this plant are filtered and dried in a concent rat e dryer. These are the copper concentrates used in the s m e l t i n g operations. Dryer p rocess gas is treated in a baghouse for dust removal and vented to the atmosphere via stack. The copper concentrate, containing approximately equal parts of copper, iron, and sulfur, is t ransferred to the Outokumpu design flash furnace for smelting. Dry concentrate and fluxes are inject ed through a concentrate burner into the flash furnace and are rapidly oxidized in an oxygen rich at mosp here. Oxygen for the flash reaction is produced by fractional distillation at the oxygen plant. Hot gas from the flash furnace, containing nearly 26 percent SO 2 , is drawn into a waste heat boiler where the heat is removed for the production of steam by the San M anuel power plant. The cooled p rocess gas is ducted to two electrostatic precipitators for dust removal prior to additional treatment in the acid plant and then exhausted to the atmosphere via one of two acid train stacks. Secondary p rocess gas from the furnace matte skimming and slag tapping launder covers are also treated by elect rost at ic precipitator and exhausted to the atmosphere via stack. The remaining products of flash smelt ing are matte and slag. M olt en copper matte, containing about 60 percent copper, is tapped through covered launders int o ladles and transferred by overhead cranes to one of three operating hot converters. In the convert ers, further oxidation of sulphur and slagging of iron and other metals takes place until the cop p er reaches a purity of 99 percent. The molten copper from the converters, called blister copper, is further fire refined for the removal of oxygen and cast into anodes in the casting department for
37 Calculations used in this section were based on the following: a. US EPA, AP-42, Compilation of Air Pollution Emission Factors, Fifth Edition, August 31, 1998. b . BHP Smelter Federal Operating Permit Application, submitted November 1, 1994. c. BHP Smelter 1998 Emissions Inventory Survey.
t ransp ort to an electrollytic refinery. Converter primary process gases are treated by Lurgi scrubber t hen ducted for treatment in the acid plant. Converter secondary hood gases are directed to elect rost at ic precipitators and discharged to the atmosphere via stack. M olt e n s l a g from the flash furnace and converters, containing small amounts of copper, is cooled, crushed, and then returned to the mill for grinding and a copper content recovery flotation op erat ion before joining other concentrate for processing in the flash furnace. Detailed process flow diagrams are included in this submittal in Appendix C. Prior to 1974, all smelting operations process gasses were emitted into the atmosphere after p art iculat e removal by electrostatic precipitators. From sulfur balance data the average emissions were reported to be 94,242 lbs/hr. The installation of an acid plant in late 1974 added SO2 control for primary converter gas. A s e r i e s of improvements in 1988 included replacement of the reverberat ory furnaces with an Outokumpu Flash Furnace. During the flash furnace conversion, BHP also installed a 690 ton per day oxygen plant to enrich t h e furnace combustion air and ret rofit t ed the existing single contact acid plant to a double-contact acid plant with a production cap acit y of 4,286 tons of sulfuric acid per day for treatment of all flas h furnace and converter p rimary process gases. The double-absorption sulphuric acid plant is t he predominant control device for primary p rocess SO2 emissions at this smelter. Process gases produced by the flash furnace and converters are cleaned of particulates in a gas scrubbing system to prepare the gas stream for treatment in the acid plant. The flash furnace provides a steady gas feed to the acid plant, enabling optimal plant p erformance. In the acid plant, the SO2 is cleaned, dried, and converted by catalyst to sulphur t rioxide (SO3 ). The SO3 is readily adsorbed in circulating dilute sulphuric acid to become salable grade acid. The acid plant provides cont r ol of process gas SO2 at or below the outlet SO2 concent rat ion limit of 0.065 percent by volume set forth in the federal New Source Performance St andard 40 CFR 60, Part P. The SO2 control performance for the BHP acid plant is an outlet emission concentration of 0.0200 percent by volume. The maximum annual process rate for this smelt er is estimated at 180-240 tons per hour (tph) of new sulfide concentrates. The production t hroughp ut of this facility, however, is dependent upon the operational capacity of the sulfuric acid p lant to treat SO2 emissions from the flash furnace and converters. The 1988 conversion included the addition of equipment to improve the collection and control of fugitive SO2 emissions and minimize the release of fugitive emissions directly to the atmosphere. T he installation of a Lurgi scrubber (a variable flow Venturi radial scrubber to cool and clean process gas prior to treatment in the acid plant) replaced a previously extensive duct system used for cooling convert er primary process gas. The old, difficult to maintain, ductwork was subject to recurring leaks and was a major source of fugitive emissions. The flash furnace, oxygen plant, acid plant, and other improvements made during the transition from the reverberatory furnaces to the flash furnace, subsequently reduced the SO 2 emissions rate by 50 percent. This improvement is demonstrated in Figure 6.1, which illustrates the pre-control and post-control ambient SO2 levels. Figure 6.2 illustrates the reduction in emissions though BHP was increasing copper production. Alt hough the converter secondary process emissions are hooded to minimiz e t he release of 49
fugit ive emissions directly to the atmos p here, fugitive emission control is also dependent upon maint enance and operating procedures. The level of control of the converter secondary hood gas is achieved through the scheduling of the copper converting process. Control of the converter process is a major contributor to this smelter's reduction in SO2 emissions. After the secondary hoods were inst alled, BHP found that the majority of secondary hood gas is generated during the roll-in and rollout of the converters. By minimizing the amount of blast air during these periods, while at the same t ime balancing the primary and secondary hood draft, more of the process gas is captured by the p rimary hoods and reports to the acid plant for treatment. This operating technique reduced the amount of fugitive emissions due to converter activity by 3,040 tpy. BHP continues to identify fugit ive emissions problem areas and correct the deficiencies as necessary. In 1999, BHP rebuilt the flash furnace, the concentrate dryer burner, and replaced an electrostatic p recip it at or with a baghouse for treatment of concentrate dryer off-gas. The new design, completed during the temporary closure period which began in M ay 1999, improved the capture of fugitive emissions and minimized the oxidation of sulfur in the dryer circuit. At this time, BHP accepted a 2,073 tpy permit limit for SO2 emissions from the concentrate dryer providing a 50 percent decrease of allowable emissions from this unit. A net decrease in future SO2 emissions is estimated at 97.17 t p y , which is approximately an 0.8 percent reduction in the total estimated smelter emissions. The emissions control improvements implemented at the BHP smelter are summarized in Table 6.1 .
T ab le 6.1 - Implementation of SO2 Control Technology Year 1974 1988 Con trol Equipment Installation of a two train sulfuric acid plant No.1 and No. 2 (primary converter gas only). R eplacement of reverberatory furnaces with an Outokumpu Flash Furnace. Retrofit to a double absorption acid plant for treatment of all primary process gas (flash furnace and converters), and installation of a new flux processing unit. Replacement of primary converter hoods and jackets and installation of a lurgi scrubber. Installation of matte skimming and slag tapping launder covers, and installation of converter secondary hoods for capture and venting of fugitive gases to the stack. 1992 1993 1994 Installation of two trim coolers on one acid plant tail stack to control acid temperature and maximize S O2 conversion to SO3 at the acid plant. Development and implementation of the optimal operating scenario for majority capture of converter process gas in primary collection system for treatment in acid plant. Installation of a new larger capacity third train to supplement the existing two train sulfuric acid plant and upgrade of Acid Plant Train II. The additional capacity allowed more of the converter offgas to be drawn into the acid plant, thereby lowering emissions from both the converter secondary hood gas as well as roof fugitives. Installation and upgrade of Acid plant train III, upgrade acid plant train II, and retrofit of No. 3 converter.
Table 6.1 - Implementation of SO2 Control Technology 1996 Installation of stainless steel ducting from the converters to the acid plant eliminating rubber expansion joints which eventually deteriorate from the sulfuric acid stream. Redesign of the secondary hooding system to reduce the gap between the hoods and converters during the scheduled converter rebuild program (rebuild of converters occurs every 2 years to ensure optimum control of fugitive emissions). 1997 1998 1999 Installation of two additional roof vent fan sulfur dioxide analyzers to quantify converter area uncaptured fugitive SO2 emissions and further identify processes associated with increased emissions. Expansion of the emissions capture capacity of the flash smelter furnace launder system by increasing volume of airflow by over 50 percent. R ebuild of the Outokumpu type flash smelter, redesign of concentrate dryer burner to minimize the oxidation of sulfur in the dryer circuit, and replacement of the electrostatic precipitator for treatment of dryer off gas with a high temperature baghouse to further minimize the oxidation of sulfur.
Fig ure 6.1 - Comparison of SO2 Emissions and Percent Control
Fig ure 6.2 Comparison of SO2 Emissions and Copper Production
6.2 Emi ssi ons Limitations for BHP 6.2.1 AAC Rule R18-2-715(F)(1), R18-2-715(G) and R18-2-715.01 - Standards of Performance for Existing Primary Copper Smelters: Site specific requirements; Compliance and M onit oring Me asure Description: In 1979, ADEQ promulgated site specific emissions limits at Arizona Administrative Rules and Regulat ions (AARR) R9-3-515, currently codified at AAC R18-2-715 (See Appendix A). The rule required all existing primary copper smelters to implement control technology sufficient to comply wit h the 1979 M PR stack limits as well as any fugitive emissions control technology necessary to assure attainment and maintenance of the NAAQS. The following emissions limits were specified for the BHP copper smelter at San M anuel: 1. Annual average stack emissions, as calculated purs u a n t to AAC R18-2-715.01(C) t hrough (J) s h a l l not exceed 18,275 lbs/hr. The number of three-hour emissions, as calculat ed pursuant to AAC R18-2-715.01(C) through (J) shall not exceed the limits as list ed in AAC R18-2-715(F)(1).
ADEQ's 2001 rule revision incorporated the following voluntary stack limits and added convert er roof fugitive limits for the BHP smelter (See Appendix A for rule revision): 1. Annual average stack emissions, as calculated pursuant to AAC R18-2-715.01(C), shall not exceed 1,742 lbs/hr. The number of three-hour emissions, as calculated pursuant to AAC R18-2-715.01(C), shall not exceed the revised limits listed in AAC R18-2715(F )(1). Annual average converter roof fugitive emissions, as calculated pursuant to AAC R18-2715.01(R), shall not exceed 715 lbs/hr. The number of three-hour emissions, as calculated p ursuant to AAC R18-2-715.01(R), shall not exceed the limits as listed in AAC R18-2715(G )(1).
Esti mate d S O 2 Emission Reduction: Emissions were reduced 480,273 tpy following compliance with the 1979 rule. Subsequent imp lement at ion of additional emissions collection and control measures enabled the 2001 revision t hat provides a further reduction in allowable emissions of 74,166 tpy. Re sponsi bl e Agency and Authority for Implementation: ADEQ is the responsible agency with authority designated by ARS �49-104(A)(11) and ARS �49422. 54
Impl e me ntati on S che dul e : T he 1979 rule provided a compliance date of January 14, 1986, unless otherwise provided in a consent decree or a delayed compliance order. The compliance date for implementation of the 2001 rule revisions is January 15, 2002. Level of Personnel and Funding Allocated for Implementation: No additional personnel are required; implementation funding for ADEQ personnel is underwrit t en through emission and inspection fees. The approximate cost to the smelter is $100,000 per annum for operation and maintenance of the ambient air analyzers. Expenditures for emissions collection and control improvements at the smelter are noted below. Enforcement Program: ADEQ is responsible for tracking the progress made through the implementation of this measure and for enforcing all applicable regulations through the schedule of inspections and the development of compliance and enforcement actions. (See S e cti on 7.3 for a description of inspection and comp liance and enforcement procedures.) Me asure Monitoring Program: BHP submitted a proposed compliance schedule in response to a 1987 Consent Decree (CIV 87106-T uc-WDB, dated September 28, 1987), for achievement of the 1979 M PR stack emission limits as expeditiously as practicable. The smelter subsequently submitted a permit application in 1987 for installation of $157 million worth of emissions collection and control equipment. All on-site const ruct ion and installation of emission control equipment and process modification was completed in 1988, meeting the incremental compliance schedule requirements of the Consent Decree. The collect ion and control technology implemented by BHP has allowed the facility to reduce emissions sufficient to demonstrate attainment and to request additional emissions reductions in 2001 (See S e cti on 6.2 for a description of the implemented equipment). For purposes of determining compliance with the emissions limits as codified in 1979, BHP was required to install, calibrate, maintain, and operate a measurement system for continuously monit oring SO2 concentrations and stack gas volumetric flow rates in each stack that could emit 5 p ercent or more of the allowable annual average SO2 emissions from the smelter. Demonstrations of stack gas volumet r i c flow rate and SO2 concentration measurement systems required by subsect ions AAC R18-2-715.01 (K)(5)(a) and (b) were initiated in 1976. The location of all stack samp ling points were approved by ADEQ in conjunction with the cons e n t decree prior to inst allat ion and operation of the continuous emission monitoring systems (CEM S). BHP installed and operates CEM S at the outlets of the acid plant train I and II (currently II and III), the 55
concent rat e dryer, the flash furnace fugitive gas circuit, and the converter secondary hood gas circuit. In addition to primary process gas, captured fugitive emissions are continuously monitored for SO2 concent rat ions and stack gas volumetric flow rates, and are included when determining compliance wit h the cumulative occurrence and emissions limits contained in R18-2-715(F)(1). M onit oring and emissions data submit t e d by BHP indicated that the smelter was in compliance with the 1979 emission limits by 1989. T o quantify converter area uncaptured fugitive emissions , BHP also installed and operates CEM S at the outlets of the converter building forced draft roof vent i l a t ors. Requirements to maint ain and operate CEM S for continuously monitoring SO2 concentrations at the converter roof vent s was included in the 2001 revision for determining compliance with the cumulative occurrence and emissions limits contained in R18-2-715(G)(1). Provisions for minimum performance and operating specifications for CEM S at this facility are cont ained in AAC R18-2-715.01(K)(5) and R18-2-715.01(S). Additional requirements for emission monit oring of the sulfuric acid plant are contained in AAC R18-2-313, Existing Source Emissions M onit oring. The BHP smelter stack and fugitive monitoring system is subject to the manufacturer's recommended zero adjustment and calibration procedures at least once per 24-hour operating period and meets all applicable performance specification and quality assurance procedures contained in 40 CFR 60, Appendix B and F. Daily calibration and quarterly audits conducted by BHP are reported t o ADEQ. To ensure continued compliance, BHP maintains on hand and has ready for immediate inst allat ion sufficient spare parts or duplicate systems for the continuous monitoring equipment to allow for the replacement within six hours of any monitoring equipment part which fails or malfunct ions during operation. As required by AAC R18-2-715.01 (L), BHP measures at least 95 percent of the hours during which emissions occurred in any month and has not failed to measure any 12 consecutive hours of emissions. BHP maintains records of all average hourly emissions measurements for at least five y e a r s following the date of measurement as required by 40 CFR 60 Subpart P - Standards of Performance for Primary Copper Smelters. All of the following measurement results are expressed as pounds per hour of SO2 , summarized monthly, and submitted to ADEQ within 20 days after the end of each month: 1. 2. 3. T he annual average of the month; T he total number of hourly periods during the month in which measurements are not t aken and the reason for loss of measurement for each period; T he number of three-hour emissions averages which exceeded each of the applicable emissions levels listed in R18-2-715.01(F)(1) (and R18-2-715.01(G)(1) subsequent to 2001 revision) for the compliance periods ending on each day of the month being rep ort ed; T he date on which a cumulative occurrence limit listed in R18-715.01(F)(1) (and R18-2715.01(G)(1) subsequent to 2001 revision) was exceeded if such exceedance occurred during the month being reported.
T hese submitted reports have shown continued compliance with all applicable regulations and averaging standards. ADEQ has not issued any notices of compliance actions for a monitoring violat ion to this facility. As a means of determining total overall emissions, BHP performs a monthly material balance for sulfur and includes the results in the monthly compliance reports to ADEQ. Based on these reports, t he smelter continues to document a sulfur recovery rate over 98 percent. The average monthly sulfur recovery rate for M ay 1997, through April 1999, was calculated to be 98.48 percent and ranged from 98.01 percent to 98.82 percent through the period. In addition to monthly compliance reports, ADEQ also receives from BHP quarterly audit, up set , and excess emissions reports, as well as annual emissions inventory reports based in part on t he SO2 CEM S data. The rule also specifies requirements regarding bypass operations. At each point in the smelter facilit y where a means exists to bypass the sulfur removal equipment, the bypass is instrumented and monitored to detect and record all periods that the bypass is in operation. The bypass has been used for maintenance failures, especially at the acid plant, with the average bypass time lasting ap p roximat ely 10 minutes. All production activities at the smelter cease during a bypass. BHP rep ort s the required information to ADEQ, not later than the 15th day of each month, and includes an explanation for the necessity of the use of the bypass. 6.2.2 AAC Rule R18-2-715.02 Standards of Performance for Existing Primary Copper Smelters; Fugit ive Emissions Measure Description: T his measure provides for an evaluation of the ambient impact of fugitive emissions from the San M anuel smelter. The regulation requires a measurement or accurate estimate of fugitive SO2 emissions to determine whether these emissions have the potential to contribute to violations of the ambient SO2 standards in the vicinity of the smelter. The rule also requires the adoption of rules sp ecify ing emission limits or other appropriate measures necessary to maintain the standards. Esti mate d S O 2 Emission Reduction: A reduction of 40,023 tpy is estimated due to implementation of fugitive emissions collection and cont rol measures. Re sponsi bl e Agency and Authority for Implementation: ADEQ is the responsible agency with authority designated by ARS �49-104(A)(11) and ARS �49422. Impl e me ntati on S che dul e : 57
T he rule provides a compliance date of January 14, 1986. Level of Personnel and Funding Allocated for Implementation: No additional personnel is required; implementation funding for the fugitive emission evaluation st udy was provided by BHP. The approximate cost of the SO2 fugitive emission evaluation study was one million dollars. Enforce me nt Program: ADEQ is responsible for tracking the progress made through the implementation of this measure and for enforcing this measure through the schedule of inspections and the development of compliance and enforcement actions (See S e cti on 7.3 for a description of insp e c t i o n and compliance enforcement procedures). Me asure Monitoring Program: Fugit ive SO2 emissions at the BHP smelter are primarily generated from the flash furnace, convert er, and anode process areas. Emissions escape the ventilation systems and exit the buildings t hrough roof vents. These structures mounted on the roofs of the building provide an escape route for uncaptured emissions. A portion of the SO2 emissions may escape through other exit points, such as open walls and doors in the building. These alternate exit points were identified by BHP t hrough flow visualization tests and survey sampling. The following studies and other data gathered demonst rat ed that the majority of the SO2 fugit i v e emissions escape from the furnace and the convert er processes and identify the converter area as the primary source of uncaptured emissions at the smelter. On April 3, 1986, BHP submitted to the Arizona Department of Health Services (ADHS) a fugit ive SO2 emissions description, evaluation, and demonstration study, to partially fulfill the out st anding SIP commitments for analysis of fugitive emissions. The study analyzed data from January 1983 through January 1984 and identified converter operations as the major source of fugit ive emissions. A fugitive SO2 emissions study of the launders was submitted on December, 1989. This study quant ified uncaptured fugitive emissions from flash furnace slag and matte tapping operations and analy z ed the ambient impacts of uncaptured flash furnace and converter fugitive emissions as well as impacts from the acid plant tail stacks. An assessment of the launders estimated a 90-95 percent emissions capture from these systems. A Differential SO2 Ambient Impact Assessment Report was completed and submitted to the Ariz ona Department of Environmental Quality (ADEQ) on January, 1993. The study compared sp ecific ambient monitored concentrations with modeled values based on actual hourly stack and c o n vert er area uncaptured fugitive emissions rates. A second analysis incorporated a cartesian recep t or grid to estimate ambient impacts from each of t he smelter sources and compared the 58
maximum impacts of stack and converter vent fugitives. Although fugitive emissions demonstrated a higher proportion of ambient impact relative to stack emissions in certain locations close to the smelt er, the studies concluded that fugitive emissions will neither cause nor significantly contribute t o a violation of the NAAQS. Summaries of the fugitive emissions studies are contained in Appendix C. M easures to improve collection and cont r o l of fugitive emissions together with control of p rimary process gasses have reduced total emissions to a level protective of the NAAQS in the San M anuel area (See S e cti on 6.2 for a description of implemented equipment). Captured fugitive emissions currently comprise approximately 36 percent of total facility emissions and are included when determining compliance with the stack limits described in Section 6.3.1. The section also det ails control of an additional 27 percent of total emissions achieved through the adoption of limits for uncaptured converter area fugitive emissions.
BHP Permit Conditions
Reasonably Available Control Technology (RACT) for sources located in SO2 nonattainment areas is defined as "that control technology necessary to achieve the NAAQS and is determined by t he technological and economic feasibilit y of the control."3 8 Submittal of biennial compliance cert ificat ions under AAC R18-2-309(2)(a) are required to demonstrate the compliance status of the source with all applicable permit conditions. Controls implemented by BHP to reduce smelter emissions and comply with emissions limit regulations are included in the following permits outlined in Table 6.2, found on the following page. Additionally, BHP submitted a standard Title V permit ap p licat ion form to ADEQ on November 2, 1994. The application for the BHP smelter including t he Outokumpu flash furnace, Pierce-Smith converters, anode furnaces, concentrate dryers, double absorp t ion acid plants, oxygen plant, gas cleaning plant including electrostatic precipitators, filter p lant , revert crushing plant and associated equipment has been processed and the final permit was issued on November 19, 2001.
T ab le 6.2 - Permit Conditions Date October 7, 1987 Permit Nu mb er 0355-88 Con trols3 9 R etrofit to install Outokumpu Flash Furnace, converter secondary hoods, double absorption acid plant to treat all process gases and new flux processing unit.
38 1994. 39
US EPA Office of Air and Radiation, Office of Air Quality Planning and Standards, "SO2 Guideline Document," February
All listed controls have been captured in the facility's Title V permit.
August 28, 1992
Installation of a new larger capacity third train to supplement the existing two train sulfuric acid plant and replacement of an existing copper converter. Shortly after the new third Train was completed, B HP upgraded Acid Plant Train II. The upgrades allowed BHP to increase the capacity of the new train, Acid Plant Train III, and take Acid Plant Train I out of service. This permit contained emissions limits for fugitive SO2 emissions as measured from the converter roof. The limit for this source was 1,115 lbs/hr (4,884 tpy). R ebuild of Outokumpu flash smelting furnace and concentrate dryer burner to minimize sulfur oxidation. Additional emission limitations, fuel usage limitations, and air pollution emission control devices were included in this significant retrofit. Permit Section II(A) further limited SO2 emissions from the concentrate dryer, to less than 2,073 tpy based on a 12-month, rolling monthly average. R evised the limits for stack and converter roof fugitive SO2 emissions to 7,629 and 3,132 tpy respectively. Requires maintenance and operation of all collection, process, and control equipment in a manner consistent with good air pollution control practice. C ontinued operation of CEMS is required to monitor and record SO2 discharge emissions rates from the smelting facility. C ontinued operation, maintenance, and calibration of all current B HP ambient monitors are also required.
March 24, 1998
July 23, 2001
7.0 MAINTENANCE PLAN Sect ion 107 (d) (3) of the amended CAA requires that nonattainment areas must have a fullyap p rove d maintenance plan meeting the requirements of Section 175 (A) before they can be redesignat ed to attainment. Section 175 (A) requires submittal of a SIP revision that provides for t he maintenance of the NAAQS for at least 10 years after the redesignation to attainment. The required components of the maintenance plan include: 1. A demonstration that future emissions of SO2 will not cause a violation of the SO2 NAAQS, 2. A commitment to continue to operate an appropriate air quality monitoring network to verify t he attainment status of the area, 3. Assurance that the state has the legal authority necessary to implement and enforce all necessary measures used to attain and maintain the NAAQS, 4. An indication of how the state will track the progress of the maintenance plan, and 5. A contingency plan that contains measures to promptly correct any violation of the NAAQS t hat occurs after redesignation. T his submittal demonstrates that all of the above required elements have been met. ADEQ also commit s to a SIP revision subsequent to this submittal providing for maintenance of the NAAQS for an additional ten years. This subsequent revis i o n is due eight years into the first ten year maint enance period.
7.1 Mai nte nance Demonstration Cop p er smelting operations at the BHP facility are the single greatest source of SO2 emissions in the San M anuel nonattainment area comprising more than 99 percent of total emissions in the area. T he conservative emissions limits that have been established for the smelter are based on actual emissions for the most recent eight quarters of smelter operations showing attainment of the SO2 NAAQS (See Chapter 4). Once the area is redesignated, any new sources or modifications to exist ing point sources of SO2 are subject to the new source permitting procedures contained in AAC T it le 18, Chapter 2, Article 4, specifically, ADEQ's Prevention of Significant Deterioration (PSD) Permit t ing Program contained in AAC R18-2-406. The regulations were established to preserve the air quality in areas where ambient concentrations are below the NAAQS and require stationary sources to undergo precons t r u ct ion review, utilizing BACT, before the facility is constructed, modified, or reconstructed. Projections of 1998 base year attainment inventories for the BHP smelter and all other point sources in the nonattainment area are included in Table 4.3 of this submittal. These projections indicat e that emissions in the area are estimated to demonstrate only slight growth through 2015. T he estimate of mobile and area s o u r c e emissions through the maintenance period is based on moderat e population growth. Projections of 1998 base year attainment inventories for mobile and 61
area source emissions in the nonattainment area are included in Table 4.4 of this submittal. Area, mobile, and point source projections are illustrated in Figure 7.1.40 Chapter 4 contains detailed p roject ion information for all sources. Although projections indicate an estimated five percent increase of point, mobile, and area source emissions through 2015, total nonattainment area emissions are four percent lower than 1997. Because the attainment emissions inventories demonstrate a st ringent level of protect ion of ambient air quality and only slight growth from 1998 base year invent ories is estimated for total source emis s i o ns, once redesignated, the area is projected to cont inue to exhibit a substantial margin of safety protective of the SO2 NAAQS.
Fig. 7.1-San Manuel Nonattainment Area SO2 Emissions Projections
Emissions (Tons/Year)
7.2 Ambi e nt Monitoring Cont inued operation of an appropriate air quality monitoring network is required to verify the at t ainment status of the area. To comply with the requirements of this maintenance plan, ADEQ and BHP, commit to continue monitoring ambient SO2 concentrations for at least 10 years following t he approval of this SIP and maintenance plan. The requirement for BHP to continue to calibrate, maint ain, and operate SO2 ambient monitoring equipment that meets EPA protocol at the Townsite,
40 Projections assume resumption of BHP smelting operations.
Dorm, and Hospital sites were made enforceable in BHP permit number 1000047. Permit number 1001582 allows the shutdown of the BHP operated ambient SO2 monitoringequipment if the facility has not operated for more than 24 consecutive months. Ambient SO2 measurement is required to resume at all facility operated sites three months prior to restarting of smelting operations. To ensure adequate representation of ambient air quality, ADEQ will continue to calibrate, maintain, and op erat e the SO2 monitoring equipment at the LDS site through the maintenance period. Any changes in monitor location that may be indicated due to future changes in conditions will be discussed with EPA Region IX prior to final decisions. All ambient monitoring data will continue t o be quality assured to meet the requirements of 40 CFR 58, Ambient Air Quality Surveillance. Dat a will also continue to be entered into EPA's Aerometric Information Reporting System (AIRS) dat abase in accordance with federal guidelines. In addition, BHP will continue to monitor ambient temperatures, and wind speed and direction for at least 10 years following the approval of this SIP and maintenance plan. The requirement for BHP to continue to calibrate, maintain, and operate ambient meteorological equipment at the T ownsit e, Dorm, and Hospital sites will be made enforceable as a permit condition for p ermit number 1000047. The provisions of this permit also allow the shutdown of the meteorological equip ment if the smelting facility has not operated for more than 24 consecutive months. M et eorological measurement is required to resume at these sites three months prior to restarting of smelt ing operations.
7.3 Ve ri fi cati on of Continued Attainment ADEQ anticipates no relaxation of any of the already implemented control measures used to at t ain and maintain the ambient air quality standards. ADEQ commits to submit to EPA Region IX any changes to its rules or emission limits applicable to SO 2 sources as a SIP revision. ADEQ also commit s to maintain the necessary resources to actively enforce any violations of the rules or permit p rovisions contained in this submittal. Permitted sources are subject to the monit o r ing and reporting, and certification procedures cont ained in AAC R18-2-306 and AAC R18-2-309 respectively. BHP submits all certifications and rep ort s as required by the above provisions (See S e cti on 4.3.1). ADEQ has authority pursuant to ARS �49-101 et seq. to monitor and ensure source compliance with all applicable rules and permit condit ions. When ADEQ identifies a violation of any applicable permit requirement either through an insp ect ion or records submitted to ADEQ, a decision will be made whether to issue a notice of op p ort unit y to correct, a notice of violation (NOV), an administrative order, or to seek injunctive r e l i e f , and/or seek civil penalties. This decision will be made based upon the following considerat ions: 1. Risk to human health, safety, welfare or the environment; 63
2. 3.
T he violator's indifference to the law; T he violator's previous compliance history.
Every notice of violation from ADEQ includes the following elements: T he factual nature of the violation. T he legal authority regarding compliance. A description of what constitutes compliance and how it is to be documented. A time frame in which ADEQ expects compliance to be achieved. Time frames shall require compliance at the earliest possible date. 5. An offer to meet. 6. A statement of consequences. If violations are not corrected within 120 days from receipt of the notice of violation, the facility is required to enter into a consent order or an executed agreement for a consent decree and a compliance schedule. M easures for addressing violations of the NAAQS are provided in the contingency plan (See S e cti on 7.4). 1. 2. 3. 4.
7.4 Conti nge ncy Plan T his contingency plan provides a procedure to ensure future compliance and promptly correct any violation of the SO2 NAAQS that may occur after redesignation of the area to attainment. Cont ingency measures do not have t o be fully implemented at the time of redesignation. The assurance that the contingency procedures outlined in this plan will be followed and commitments will be implemented and enforced is contained in state law at ARS �49-402 and �49-404. Because t he BHP Copper San M a nuel smelting facility is the major source of SO2 emissions in the nonat t ainment area, the contingency measures presented in this section focus primarily on ambient imp act s of emissions attributable to this facility. Contingency measures for all other point sources are provided by the Prevention of Significant Deterioration (PSD) requirements contained in AAC R18-2-403 and AAC R18-2-406.41 A first occurrence in a calender year of a verified 3-hour average SO2 level in excess of 0.425 ppm but less than 0.5 ppm (85 percent of the secondary NAAQS but less than 100 percent) shall require not ificat ion as described in the procedures below. A second occurrence in a calender year of a verified 3-hour average SO2 level in excess of 0.425 ppm but less than 0.5 ppm (85 percent of the secondary NAAQS but less than 100 percent) or any occurrence of a verified 3-hour average SO2 l e v e l in excess of 0.5 ppm (100 percent of the secondary NAAQS), recorded at any ambient monit oring station, has been selected as the protective trigger level (P T L). When the PTL is exceeded, there will be ample time to complete all necessary facilit y inspections and technical
41 State regulations comply with the federal requirements found in: 40 CFR 51.307 (NSR); 40 CFR 51.166 (PSD).
evaluat ions, develop recommendations, and implement necessary mitigation measures to prevent any violat ion of the SO2 NAAQS. M ult ip le exceedances (either sp a t i a l l y or temporally) shall be considered a single event during an episode.42 Special M easures described below for a second occurrence in a calender year of a verified 3-hour average ambient SO2 level over 0.5 ppm (a violation of the secondary N A A Q S) , provide added protection to prevent a violation of the air quality st andards. 7.4.1 Notification Procedure
BHP will record the hourly concentrations for all facility operated ambient monitoring sites. ADEQ will record the hourly concentrations for the state operated ambient monitoring site. For the BHP operated SO2 monitors, the facility respons i b l e official must notify ADEQ as soon as p ract icable, but no later than the close of the next business day after initially verified monitoring data indicat e that an ambient SO2 level in excess of 0.425 ppm has been recorded. F or the ADEQ op erat ed SO2 monitor, ADEQ must notify the BHP responsible official as soon as practicable, but no later than the close of the next business day after initially verified monitoring data indicate that an ambient SO2 level above 0.425 ppm. The facility will also have access to ADEQ's data.
First Action Level
T hese actions must be completed as soon as practicable, but no later than 24 hours following an event and should include at a minimum: 1. A full calibration check of the ambient SO2 analyzers and recording systems, and review of all applicable records of environmental conditions and electrical supply at the monitor at the time of the exceedance. Final validation will be based on current EPA and ADEQ qualit y assurance guidelines, Insp ect ion of all ductwork and hooding associated with the flash furnace process and fugit ive gases and the converter process and secondary hood gases, Assessment of the acid plant to ensure that this facility is operating within parameters recommended by the manufacturer for optimal performance within the New Source Performance Standards limits, and Insp ect ion of all other processing equipment.
2. 3.
If it is determined that the exceedance of the PTL or NAAQS was due to invalid ambient monitoring dat a no further action is necessary.
42 For this SIP, an episode commences at the time that the first exceedance begins and an episode shall conclude at the end of
th e 3-hour period following the last exceedance that can be attributed to the same cause.
In the event of a valid exceedance, BHP will, as soon as feasible
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