Touring and discussing copper mines

On Saturday, we visited the ASARCO Copper Mine which is west of Tuscon. We started by viewing exhibits in the museum that displayed the many uses of copper. We learned how copper is extracted and refined. The exhibits, as well as our tour guide, emphasized the importance and high demand for copper in our society. Arizona has 65 percent of the copper deposits in the United States. Therefore, copper mining is an important component of the state’s economy. Copper is mostly used in conducted electricity in many households and machines. During the tour, we noticed how ASARCO gave very little information on the mine’s environmental impacts. They assured us that they were restoring sites used for excavation, which are the finely ground, unwanted rock material the copper is extracted from.

We visited the mine to further understand the impact large scale mining has on the desert ecosystems. We discussed a proposed copper mine that would be built along the foothills of the Santa Rita Mountains, not far from the Santa Rita Experimental Range. This mine would be built on private property, but the tailings would be located on Forest Service land. This has caused considerable controversy between state agents, federal agents, and the Rosemont mine company. Many people are concerned the mine would destroy fragile habitat, contaminate water, and disrupt tourism to the Santa Rita Range. The Canada based company claims it would have a minimal impact on the environment and try to reclaim much of the used land. Many environmentalists are skeptical of these claims based on mines like the ASARCO copper mine which have been unable to successfully reclaim large amounts of the mined land.

The Rosemont Mine, like the ASARCO mine, would be an open pit operation. The ASARCO mine uses over 21,000 acres, but the pit only attributes to a small fraction of this land. A large majority of the land is used to dump the tailings into large, shallow ponds. The problem with reclaiming land used in an open pit mine is that much of the ground has been disturbed by excavation. The overburden, excess rock that sits on top of the copper ore, sits in large mounds around the pit. The rock has no value in terms of growing new plants and supporting life in the desert which, as we have learned in great detail in this course, supports a vast degree of life. The pit is so deep it exposes the water table. This poses a risk to lowering the water table because it is exposed directly to the sun and evaporates, drawing more water from the surrounding, unexposed part of the water. This is one of the many ecological problems the mine poses.

After seeing the pit of the mine, many of us felt it inflicts a tremendous amount of ecological damage, despite restoration efforts. The federal government has taken measures to ensure mines such as these reduce their environmental impact as much as possible. We described the mine as a necessary evil because despite the ecological damage, copper is in high demand, especially with more sustainable technologies such as solar panels and electric cars. Through our discussions, we concluded that the need for copper is unavoidable, so sustainable mining will require the federal government to ensure the mine is following strict environmental standards and future mines are carefully selected.

A truck bringing waste rock out of the mine. The truck is about the length of three school buses.
The ASARCO pit mine. It is more than 1600 feet deep and 1.5 miles wide.