Letters

Henderson Mine a Promising Candidate for Underground Lab

Several sites are being considered for a National Underground Science and Engineering Laboratory (NUSEL), according to a news story in the February 2004 issue of Physics Today (page 32). Those locations, including the Homestake and Soudan mines and the Icicle Creek site, each have specific attributes that make them possible choices. The article quotes Kenneth Lande of the University of Pennsylvania as saying that "Homestake has a clear advantage [over other sites] financially, and in terms of timetable." Yet water pouring into Homestake will require extensive and expensive rehabilitation measures just to regain the status quo in a mine that is more than 100 years old. Missing from the site list, however, is one in Colorado that may prove to have the greatest potential of all the proposed locations.

Late in 2002, personnel from the Henderson molybdenum mine, located in central Colorado and owned by Phelps Dodge Corp, came to the Clear Creek County Planning Commission to ask if there was any interest in preserving certain of the mine's facilities for use after the forecasted date for mine closure. Much of the infrastructure, including office buildings, maintenance and machine shops, utilities, water supplies, and sewage treatment facilities were considered highly valuable for redevelopment.

The Henderson mine is located on a 30 000-acre private land parcel in the Arapaho National Forest; the land spans the Continental Divide 40 miles west of Denver, is accessible by Interstate 70 and US Highway 40, and is slightly over one hour from Denver International Airport. The mine consists of more than 150 miles of roughly 15-foot-diameter drifts. The main shaft is 28 feet in diameter with a vertical elevator capable of carrying up to a 50-ton load to the lowest level of the mine.

Mining operations at the Henderson are projected to cease around the year 2020. However, large areas are currently available underground some distance from the mining area, and many uses could coexist with current mine production. Crushed rock and ore are brought to the surface from the mining area by a nearly horizontal conveyor, through a 10-mile-long straight tunnel under the Continental Divide. Two 30-mW substations are fed from two independent 115-kv transmission lines and provide 100% redundant electrical power to the complex. Fiber-optic communications link the entire facility, above and below ground.

In October 2003, the Arapaho Project Inc, a private nonprofit corporation, fostered the formation of the Colorado Alliance for Underground Science and Engineering to further evaluate the Henderson mine's potential for high-energy physics. CAUSE members include the Arapaho Project, the Colorado School of Mines, the University of Colorado at Boulder, Colorado State University, and the Henderson mine. CAUSE is currently working in the physics community to increase awareness of Henderson and its potential for economical, high-energy physics research.

We believe that the scientific community, and particularly the particle and high-energy physics group participants, would benefit immensely from a close and unbiased evaluation of the Henderson site's potential as a national underground laboratory.

In December of 2003, CAUSE members visited with NSF officials regarding NUSEL and other high-energy physics projects. In April 2004, CAUSE founded the Henderson Underground Science and Engineering Project. HUSEP is in contact with NSF regarding the release of new NUSEL solicitations and will submit a proposal for.