Summo awaits feasibility

Solvent extraction techniques are proving increasingly attractive to conventional copper mining companies as they struggle against historically low prices.

One such company, Denver-based Summo Minerals (SMA-T), has its sights set on becoming a profitable mid-tier producer of cathode copper from medium-sized open-pit deposits that are amenable to these recovery techniques.

Currently, Summo’s efforts are focused on Lisbon Valley, a fully permitted open-pit/heap-leach project designed to produce 40 million lbs. of cathode copper annually at a cash operating cost of US48 per lb.

The project is in southeastern Utah, at the southeastern end of the faulted Lisbon salt anticline. The Lisbon Valley Fault is a major axial structure that exhibits up to 4,000 ft. of displacement and, outward from the fault, as much as 1,500 ft. along favourable sandstone beds. The deposit has at least 46.5 million tons of reserves grading 0.43% copper with a 2.36-to-1 stripping ratio, and is still open to expansion.

The project, which is undergoing a feasibility study, was permitted in 1997 but had to fight off an environmental challenge that was later defeated in 1999. Two years earlier, a US$45-million project loan had been approved for the mine, but the loan commitment expired while the company was fighting off the challenge by environmentalists.

Once the latest feasibility study is completed, Summo will arrange a new loan so that construction and development can begin. In the meantime, drilling will resume on the southeastern extension of Centennial, the largest of three oxide deposits at Lisbon Valley.

At the same time, Summo will continue to seek advanced-stage copper-oxide projects throughout the Americas, including Mexico and Chile, to complement production at Lisbon Valley. For example, Summo and Mexican-based Minera Terrazas recently entered into an agreement to explore the Terrazas copper-zinc oxide property in Mexico.

A permitting application is being prepared for a 20,000-metre drill program that could get under way in the second quarter of 2000. According to Summo, “the drill program is designed to upgrade the drill density on the current resource in order to allow for reserve calculations once adequate site-specific economic and engineering data are available.”

Already, limited channel sampling has indicated grade enrichment near the surface, though this has yet to be verified by drilling. Should the initial results hold up, operators would mine and recover higher-grade ore during the initial years of production.

Resource Capital Fund holds an approximate 31.4% interest in Summo, whereas St. Mary Minerals owns 19.25%.