The Arizona Republic takes a long and hard look at water resources for new mines in Arizona. Here is a collation of bullet points culled from their full report (links added by me):

  • At least seven new mining projects are being planned in Arizona . The new projects will require 40,000 acre-feet of water annually.
  • The planned Resolution Copper mine near Superior will need as much as 20,000 acre-feet of water annually.
  • The new Phelps Dodge mine near Safford will need 5,500 acre-feet per year. E&MJ reports in the June issue that the mine is constructing “diversion structures in the foothills above the mine to prevent runoff from even entering the site, as well as an enormous (390 acre-feet plus freeboard) overflow pond designed to contain more than twice the volume of stormwater runoff and solution draindown resulting from a 100-yr, 24-hour storm event and a concurrent 24-hour power outage.”
  • The proposed Carlota mine outside Miami will need 1,200 acre-feet per year. Carlota project manager Blakely said the company plans to develop a well field near the mine that would produce 1,200 acre-feet of water per year. But up to 318 acre-feet of that could be dumped directly into nearby Pinto Creek to prevent its flows from being diminished by the groundwater pumping. Stations would monitor the level and temperature of the creek, and water would be automatically released to maintain both at a constant level.
  • The proposed Rosemont Ranch mine in the Santa Rita Mountains, 30 miles southeast of Tucson would require about 5,000 acre-feet of water per year. The developer is proposing to pump water from an aquifer near the mine and replenish it with excess CAP water it plans to buy. The commitment to recharge CAP water is above and beyond what Arizona law requires. The company also has agreed to use a dry-tailings process that would cut the mine's water demand in half.