To the editor:
In a recent news article regarding Kennecott's usage of recycled cans in the leaching process at our Bingham Canyon Mine, several allegations were made about the creation of hazardous waste that are erroneous. The following is provided as clarification to inaccuracies in the articles:No hazardous wastes are produced during the leaching process and no leach dumps have been abandoned with hazardous wastes on top. No state or federal environmental agency has classified any of the leaching products as a hazardous waste.
From a recycling standpoint, the use of "detinned" cans and iron scrap in the copper production process is one of the best examples of total recycling. Iron is produced by mining and made into tin cans and other steel products beneficial to society. Once the primary uses of the iron are complete, the iron scrap is used to produce copper. The iron is returned to its natural form in a mining environment. The cycle is complete, from mine to mine, without having to discard the iron in landfills across the country.
Kennecott has been producing copper at Bingham Canyon by the leaching process since the 1930s. The copper leaching process enables Kennecott and other mining companies to recover copper from very low-grade rock. Without the use of leaching technology, valuable copper would be left, unrecovered in the overburdened stockpiles associated with all western U.S. copper operations.
The copper leaching process is simple, environmentally safe and, at Bingham Canyon, produces approximately 6,500 tons of copper per year.
No sulfuric acid is used in the process. The leach solutions are mildly acidic, but this is a result of the natural leaching chemical reaction, not a result of sulfuric acid use.
All iron scrap used in the precipitation cones is tin cans and other recycled iron, which is "detinned" and shredded by the recycler prior to delivery to Kennecott.
All detinned, shredded iron scrap is delivered to Kennecott by railroad.
The iron that goes into solution in the precipitation cones is carried in solution onto the stockpiles. The iron is deposited both on the surface and interior of the stockpile in a stable, inert form, similar to rust.
For every three pounds of iron consumed in the process, one pound of copper is produced.
No iron is "melted." All of the iron is dissolved or consumed within the precipitation cones.
We'd hate to see recycling efforts diminished in any way because of the inaccuracies of a single newspaper article.
Gregory H. Boyce, director
Government and Public Affairs