Nationwide Inventory of Abandoned Hard Rock Mines on Federal Lands Is Unavailable

Attempts to determine how many hard rock mines lie abandoned nationwide have not resulted in a definitive inventory of these mines on federal lands. The four major land-managing agencies are in various stages of inventorying the abandoned mines on the lands they manage. According to the Forest Service, there are about 25,000 sites within National Forest boundaries. Abandoned Hard Rock Mines Generally Pose Two Kinds of Hazards

The problems posed by abandoned hard rock mines can generally be classified as physical safety hazards or environmental degradation. Furthermore, the factors the agencies use to classify their inventories are not consistent from agency to agency. Specifically, the Mineral Policy Center classified the sites as follows: 194,500 were benign, needing little if any remediation; 231,900 needed revegetation or landscaping; 116,300 presented safety hazards needing prompt but not necessarily extensive action; 14,400 needed extensive work to prevent surface water contamination; 500 needed complex work to prevent groundwater contamination; and 50 were Superfund sites, posing a severe threat to the public and needing complex cleanup. The agencies have completed a few such detailed site analyses. Cost Estimates by Other Federal Agencies

The Bureau of Mines estimated the “worst-case” cost of reclaiming abandoned mine sites on federal lands at between $4 billion and $35.3 billion. Estimates of Number and Types of Sites and Cost to Reclaim, by Organization

Degree of hazard, degree of environmental impact, accessibility $165 million (about $40 million short-term)
Six categories ranging from “benign” to “Superfund”

Objectives, Scope, and Methodology

The Ranking Minority Member, House Committee on Resources, asked us to report on the (1) approximate number of abandoned hard rock mines on federally managed land, (2) types of hazards these mines pose, and (3) approximate cost to reclaim these mines.
Why GAO Did This Study

Pursuant to a congressional request, GAO provided information on abandoned hard rock mines on federal lands, focusing on the: (1) approximate number of such mines; (2) types of hazards the mines pose; and (3) approximate cost to reclaim the mines.

What GAO Found

GAO found that: (1) the four major federal land managing agencies are each taking inventory of the abandoned mines on the lands they manage, but because the agencies do not use consistent methodologies to develop their estimates, there is no definitive inventory available; (2) the Forest Service has estimated of the number of abandoned mines on federal lands to be up to 25,000 sites; (3) nonfederal entities are also working to standardize terminology and guidelines to aid in future inventories; (4) abandoned hard rock mines can pose physical safety hazards, cause environmental degradation, and contaminate water; (5) the agencies use different factors to classify their sites for risk, and only two of the four agencies rank the severity of hazards; (6) nonfederal organizations have determined that 194,500 sites were generally safe, while 231,900 needed landscaping, 116,300 presented minor safety hazards, 14,900 could cause water contamination, and 50 threatened public safety and required complex cleanup; (7) the agencies have not completed the fieldwork needed to identify the number and types of problems on their sites; and (8) the Bureau of Mines believes that worst-case scenario costs could range between $4 billion and $35.3 billion and nonfederal organizations estimate that costs could exceed $70 billion, but no comprehensive cost estimate for reclaiming abandoned hard rock mines on federal lands exists.