The Silver Bell district in Arizona provides a good example of various electrical and electromagnetic methods applied to the same porphyry copper deposits. Lowest resistivities in the Silver Bell area corresponded with the quartz monzonite porphyry and with zones of sericitic alteration. Likewise, highest IP responses were associated with sericitic alteration. The low resistivities at Silver Bell are caused by the strongly fractured nature of the porphyry system, particularly in sericitic zones, and its interconnected sulfide veinlets. Sericitic zones are highly conductive because of intense fracturing, abundant pyrite mineralization, and sericitic alteration. The higher resistivities of the potassic zone, on the other hand, reflect silicification, disseminated sulfides (as opposed to sulfides deposited in veinlets), and overall less abundant sulfide and clay minerals. Propylitic zones are less fractured and have much lower total sulfides and, thus, higher resistivities. Resistivity weakly correlates with the leached cap and underlying zones of enrichment.

The mine operates four open-pits (North Silver Bell, El Tiro, West Oxide and East Oxide). All copper in these pits will be extracted from the ore utilizing either of two hydrometallurgical processes: dump leaching or rubblization. Approximately 50% of the ore will be mined and hauled to dumps for leaching. The remaining 50% will be rubblized. Rubblization is the process where material is drilled, blasted, and then leached in place. Each month 1,800,000 tons of ore and waste are mined, and 700,000 tons of ore is rubblized. The four open-pits and other plant facilities are situated on 19,000 acres. Mining affected areas of the facility total 3,900 acres.

Copper-bearing solutions from the dump leach and rubble areas are collected and pumped to the solvent extraction plant where the copper in solution is concentrated over 30 times before being pumped to the tank house. In the tank house, the copper is recovered from solution using the electrowinning process and plated on stainle ........