wells along the Dolores River. The system then dilutes the brine with water and a corrosion inhibitor and transports it to a high-pressure injection well, where it is deposited deep into Precambrian and Paleozoic rocks. A 2001 study found that the total salt reaching the Dolores had declined by about 90%, although this may have been the result of a period of low precipitation during the measurement period. As of 2009, the PVU removes about 113,000 tons of salt annually from Paradox Valley. The injection well of the Paradox Valley Unit has induced thousands of earthquakes, including at least 4,000 prior to the year 2001. Most were below the threshold of human detection, but at least 15 have been over 2.5 in magnitude, the largest being a 4.3 magnitude quake on May 27, 2000. The PVU suspended operations for 28 days following this quake, but later resumed injections at a lower rate. Further earthquakes have been linked with the operation, including a 3.9 magnitude quake in 2004. Piñon Ridge Mill In 2009 Energy Fuels Resources Corporation, a subsidiary of Toronto-based Energy Fuels Incorporated, proposed the construction of a uranium mill in the southeast end of Paradox Valley. Called the Piñon Ridge Mill, it would have been capable of processing 500 tons of uranium ore per day. Legal action tied up the project for many years, and as of September 2020 the project appears to have died. See also Paradox basin Paradox, Colorado References External links Upstream and downstream water quality data from the United States Geological Survey Photo of Paradox Valley near Bedrock, CO on Panoramio Landforms of Montrose County, Colorado Valleys of Colorado Geology of Colorado