SALT Activities

SALT: Superstition Area Land Trust

For a few years I was involved as a volunteer with SALT (Superstition Area Land Trust). SALT's primary mission is to assure the long-term conservation, perservation, and management of natural open spaces surrounding the Superstition Wilderness Area. With my geological background, I became involved with helping to evaluate the planned development of a major local copper mining program that was proposed by Resolution Copper for a region only about 15 miles east of Gold Canyon. I read many geological, hydrological and mining documents and attended corporation-sponsored community meetings to act as an intermediary between the scientific and engineering content of those meetings and the community understanding, as represented by the SALT board. The corporation meetings and presentations occurred with fair frequency prior to the federal acceptance of the project via a political bill sponsored by Arizona Senator John McCain, but once it was accepted and passed by congress the presentation frequency by the corporation decreased and my involvement also decreased.

This is the town of Superior, AZ, which is a historic copper mining town. Superior is located at the edge of a plateau at about an elevation of 4,400 feet which is capped by the volcanic rocks that make up the Superstition Mountains. The shear cliff in this image is known locally as "Apache Leap," although I don't think there is any reliable documentation that the named event actually occurred. The new copper mine is sited on the plateau just beyond the cliff edge. One of the main community concerns is that the prposed mine does not destroy the Apache Leap feature.

This poster, provided by Resolution Copper at a public presentation, shows an arial view of the town of Superior (left), the Apache Leap escarpment (center), and the area to be mined (right). The copper deposit lies at great depth and the proposed mine will be developed beneath the deposit and will mine it from below using a technique known as "block cave mining." This mining techique will ultimately create a large collapes depression on the plateau surface that will measure about 1.5 miles in diameter and will be about 1000 feet deep in its center. This expected depression is shown on the right side of this panel.

This panel shows the plateau and the copper deposit beneath, with some of the six 7000-foot deep vertical mining shafts that will need to be developed to facilitate the mining. As of summer 2018, one shaft has been completed and work is proceeding on the second one. The actual mine floor will be located 2,600 feet below sea level.

The panel above shows a geological cross-section through the copper deposit. Notice, in particular, the 1 percent copper abundance shell that defines the main portion of the deposit. This poster was presented at one of the public meetings that was held by Resolution Copper.

These are the elevator structures on top of the mine shafts that are being dug to the 7000 foot deep level, where it is reported the temperature of the wall rocks is about 180 degrees Fahrenheit, which is hotter than the typical temperature of a cup of hot coffee. Perhaps not surprisingly, most of the mining will be accomplished by remotely controlled machines.

Here we are driving a back road that is at or very near the area that will be covered by the tailings (the crushed rock that remains after the copper minerals have been removed) as a result of the mining.

This company-supplied planel shows the planned area that will be covered by the tailings over the course of the anticipated 40 year lifetime of the mining operation.

This is the drill core facility in which all drill cores associated with this project are kept and analyzed. Because the deposit is so deep, there are no surface exposures of these copper-containing rocks.

Here in the drill core facility the drill cores are being displayed and studied.

For more information about SALT, see the following: https://www.azsalt.org/

For more information about the Resolution Copper mine, see the following: https://resolutioncopper.com/resolution-copper-mine/