1st Draft

USE OF CYANIDE IN MINING

The proposed amendment to the Colorado Constitution:

Prohibits two ways of using cyanide to extract gold and silver from new open pit

mines; and

Prohibits the expansion of existing open pit mines that extract gold and silver in

these two ways.

Background

There are 79 active gold and silver mines in Colorado. Currently, two open pit mines extract gold using a type of cyanide processing that is prohibited by this measure. The other gold and silver mines extract minerals through a variety of processes. Open pit, also known as open cut, mining is a method of removing ore from the surface of the earth. Ore is rock that contains valuable minerals such as gold and silver. Cyanide processing is used to extract minerals from large amounts of low-grade ore.

This measure prohibits mineral extraction using cyanide with heap and vat leaching. In heap and vat leaching, the ore is crushed and a diluted cyanide solution is applied. During the heap leaching process, ore is heaped on a double-lined, plastic leach pad that is designed to capture the cyanide solution. In vat leaching, the ore and cyanide solution are combined in a large vat or tank. The minerals are recovered from the cyanide solution once the leaching process is completed. The cyanide solution is either reused or held in covered, lined ponds where the solution is neutralized.

Mines that use cyanide must comply with federal and state water quality laws and regulations. The state requires mines to have a permit to use cyanide and an environmental protection plan. The plan describes how the mine will protect wildlife and water resources from the cyanide processing operations. Each mine must have a state-approved emergency response plan to follow if an accidental release of cyanide occurs. Mines must also prove that they are financially capable of correcting environmental problems. The state inspects the operations annually to ensure that these environmental safeguards are in place.

Arguments For

1) The potential for environmental damage will be reduced if open pit mines are prohibited from expanding their cyanide processing operations. Cyanide is highly toxic and small amounts can kill animals and humans. In the late 1980s, cyanide and other pollutants escaped from an abandoned open pit gold mine in southern Colorado killing aquatic life in the nearby Alamosa River. The mine used cyanide solution in its heap leaching mineral extraction process. There is never any assurance that environmental safeguards are completely reliable. Within the past ten years, leach pads have torn and pipes carrying cyanide solution have ruptured allowing cyanide to escape into the environment. A major release of cyanide solution may cost millions of dollars to remedy. If the mine cannot pay the total clean-up cost, the state may be financially responsible.

Arguments Against

1) The measure unfairly restricts the expansion of two active open pit gold mines when other types of mining operations use the same mineral extraction process. For example, underground mines can continue to use cyanide heap and vat leaching to extract minerals such as lead, zinc, copper, molybdenum, and gold. The restriction would economically impact the two open pit gold mines because cyanide processing is the least expensive and most efficient way to extract gold from low-grade ore. One of the mines is the largest employer in Teller County and offers some of the highest paying jobs in the area.

2) The measure is unnecessary because there are reliable environmental safeguards in place. In 1993, the state implemented strict new environmental standards. For example, leach pads must be double-lined. Other structures that hold cyanide solution are also

required to meet specific design and construction standards.