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Glacier Mine, Wrangell-St. Elias National Park and Preserve, Alaska
The Kennecott Mines are located on Bonanza Ridge, several thousand feet above the Kennicott and Root glaciers in Wrangell- St. Elias National Park and Preserve, Alaska. Between 1900 and 1938, five distinct mines were developed at Kennecott, each with its associated surface camp: Bonanza, Jumbo, Mother Lode, Erie and Glacier. All of the mines are situated adjacent to a greenstone-limestone contact which defined the location of ore on Bonanza Ridge. Glacier Mine was constructed to support the extraction of the West Slide ore body, which unlike the Jumbo and Bonanza deposits, was formed by the erosion of extremely high grade ores in the Bonanza outcrop that slid downslope into the lateral moraine and ice mass of an alpine glacier, thus making the ore encased in glacial ice rather than loose in the scree. Notable exploratory work occurred in 1917 when two tunnels were driven to examine the extent and quality of the ore. A third tunnel was driven later to further define the ore body. These tunnels ran parallel to the lateral moraine and several crosscuts ran at right angles to determine the width of the deposit. Miner’s worked inside the glacier, drilling, blasting, and timbering tunnel walls as they would in rock. By 1918, a sufficient amount of ore was located to justify expenditures on the labor, materials, and equipment to remove it and construction began on a 5,000’ long aerial tramway as well as a loading and sorting station at the toe of the glacier. Glacier Mine was immediately put into production once the aerial tramway was completed in 1920. The future of the mine appeared promising as the February 1920 issue of Economic Geology reported Glacier Mine had been ‘explored by three tunnels from which several crosscuts had been run enabling the ore to be partially outlined and sampled.’ Allegedly, over 100,000 tons of ore had been developed by this time and further development was planned. Several artificial thawing experiments were conducted, but the increased cost of mining during the winter was too great for the return. As such, the mine was worked approximately three months out of the year, July through September, when the glacial ice melted sufficiently to release the ore. Eventually, drilling and blasting were abandoned in favor of using scrappers and winches on the surface to efficiently move ore from the mine to the sorting facilities below. By 1928, the ore was worked out of Glacier Mine and its equipment was relocated to support other operations at Kennecott after its closure. No further work was done at Glacier Mine thereafter. Although the Kennecott Mines were in operation for only a short period of time, they collectively produced over 4.6 million tons of ore valued at $200 million. Glacier Mine alone produced over 163,028 tons of ore and 3,526 tons of copper, contributing to the success of the Kennecott Mines.
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