Rosemont Copper Mine

Rosemont Copper Mine policy statement

Adopted February 9, 2016

The Community Water Coalition agrees with the U.S. EPA’s recommendation that the proposed Rosemont Mine “should not be permitted”, due to the lack of an adequate mitigation plan and the unsustainable and irreversible impacts to the local environment. These include:

Impacts to water quantity in the Santa Rita Mountains and surrounding areas:

  • Mining companies are exempt from the Groundwater Management Act of 1980. This allows the company operating Rosemont Mine to export unlimited amounts of water from the Tucson Active Management Area, which is illegal for other entities.
  • Annual water use by the mine would be enough to supply tens of thousands of single-family homes.
  • Continuous groundwater pumping at the mine site will create a massive cone of depression in the regional aquifer throughout the life of the mine. After the mine’s closure, groundwater will continue to be drawn to the pit in perpetuity as it fills with water, which is then lost to evaporation.
  • Groundwater pumping can exacerbate subsidence caused by drawdown of the local aquifer near the Sahuarita and Green Valley area, impacting nearly 1,000 privately-owned wells.
  • Groundwater pumping at the mine site, combined with the disposal of waste rock and toxic tailings, threaten to destroy 60 – 100 natural springs.
  • Degradation in nearby Davidson Canyon will alter natural hydrology and recharge functions in the area.
  • Dewatering of the aquifer of Davidson Canyon and Cienega Creek watersheds has a high likelihood of eliminating surface water flow, which will affect many species, including some that are listed as threatened or endangered.

Impacts to water quality in Southern Arizona:

  • There are seven discharge points regulated by Rosemont’s Aquifer Protection Permit, covering a large range of contaminants. The permit allows discharge of toxic pollutants into the groundwater for two years before establishing a baseline for groundwater contamination and regulating further discharges.
  • Acid mine drainage is inevitable, and there is a high risk of mine spill disasters.
  • The dry stack tailings technology proposed for Rosemont Mine is untested in this type of climate and its potential effects are unknown. This could threaten the Cienega Creek Biological Conservation Preserve and the groundwater supply for the Tucson Basin.

To protect Arizona’s unique environment and precious water resources from overuse and degradation, the Community Water Coalition proposes the following actions:

  • Continue to educate citizens on negative impacts of Rosemont Mine on water supply and security.
  • Continue to advocate with local decision makers to ensure the protection of Tucson’s water resources.
  • Continue to support efforts by CWC partners to identify and document surface and groundwater resources that will be threatened by the mine.
  • Promote economic development that supports and protects the environment over destructive developments such as mining.