The Cyprus Sierrita and Cyprus Twin Buttes mines are located adjacent to each other, south of Tucson and west of Green Valley. Water use at theses two mines totaled 26,165 acre-feet in 1997. Copper and molybdenum are mined at two open pits and an underground mine at the site. A substantial amount of silver also is recovered as a by-product. Water use at the Mission Mine was 13,042 acre-feet in 1997.
Copper is mined in an open pit.
Water use at the site was 575 acre-feet in 1997. On-site production capacity has been expanded with the mining of a new deposit and the addition of a new processing plant. Most mining in the Tucson AMA is open-pit mining followed by milling and flotation. The ore extracted from the pits is crushed and delivered to the mill, where it is crushed again and mixed with water to form a slurry. The slurry is discharged to flotation cells.