Summo USA Corp. has proposed digging four open-pit copper mines on public land in Lisbon Valley near the Colorado border.
The largest of the four would be about a half-mile long, a quarter-mile wide and 350 feet deep. The remaining three would be considerably smaller, said Robert A. Prescott, Summo's vice president for operations.Copper would be extracted from the low-grade ore through a "heap leach" process in which diluted sulfuric acid is sprinkled over the crushed rock.
The mine would produce 34 million pounds of copper a year for the next 10 years, said Prescott.
As many as 105 people would work at the mine, most driving about 45 miles to the site from Moab or Monticello.
Lynn Jackson, a land and mineral specialist for the U.S. Bureau of Land Management in Moab, said the BLM will prepare an environmental-impact statement on the mine proposal. It is expected to be completed by September. If no serious problems are identified, work on the $48 million project could begin early in 1997 and production could start later in the year.
Jackson said the area proposed for mining already contains several small pits left from copper mining in the 1940s and 1950s. Those projects removed most of the high-grade ore. Summo believes it can profitably tap the remaining lower-grade ore using large-scale mining techniques and the relatively inexpensive heap-leach method.
This approach has been used to open gold mines throughout the West during the past decade. The only difference with this mine is that sulfuric acid would be used to extract the copper, while cyanide is used to extract gold.
"Sulfuric acid isn't great, but it's a . . . sight better than cyanide," said Jackson.
Current standards for this type of mine require the ore to be placed on plastic liners before being sprinkled with sulfuric acid to prevent contamination of the soil and groundwater.