The Crescent Mine has been owned by Shoshone County, Idaho and the U.S. Environmental Protection Agency since the early 1990's.
The Crescent Mine is a past-producing high-grade silver mine, located just east of Kellogg, Idaho in the Coeur d'Alene mining district in Idaho. Mining has been carried out in this district for more than 100 years; it is the only known mining district in North America to have produced over 1.1 billion ounces of silver in the last 100 years (source: Idaho Geological Survey Bulletin #28,1989).
The Crescent Mine is reported to have produced over 25 million ounces of silver, from 1917-1981. According to a Bunker Hill geological staff report, produced on Jan 1st 1982, production totaled 978,750 tons averaging 27 ounces per ton, recovered silver was 25,139,655 ounces.
The Crescent Mine is strategically located between two world-class ore bodies. Adjoining the Crescent Mine on the east side is the world famous Sunshine Mine, one of the richest silver mines in the world. The Sunshine has produced over 325 million ounces of silver, 71,000 tons of lead, 50,000 tons of copper and 37,500 tons of antimony. Bordering the Crescent Mine property on the west is the Bunker Hill Mine with a production history of 3,119,121 tons of lead, 161,384,305 ounces of silver and 1,311,266 tons of zinc.
History of The Crescent Mine
Development work began on the Upper Crescent Mine at the turn of the century. By 1917, the mine had begun producing ore from along the Alhambra fault.
In the summer of 1943, the Crescent Mine was closed. The Bunker Hill Company reopened the mine in 1951, and by June of 1954 the Ellis (No. 1) shaft had been sunk from the 1,200 level to the 3,100 level. By the end of March, 1963, the stopes developed between the 3,000 and 2,500 level had produced in excess of 3.5 million ounces of silver.
Total proven, probable and projected ore calculated in 1983 by Don Springer, an independent consulting geologist, prior to the Crescent Mine's final shutdown was 396,500 tons of ore with an average grade of 23.7 ounces per ton silver for a total resource of 9,395,380 ounces of silver.
Geology
The Coeur d'Alene District is underlain by members of the Precambrian belt super-group rock formations, which in the area of the mine are, in descending order, the Wallace, St. Regis, and Revett Formations. This super-group extends east-westerly for many miles and hosts the numerous mines that have made the District one of the major silver, lead-zinc producing areas in the world and the premier silver district in North America. Within the Coeur d'Alene Mining district, the largest silver producing mines have in the last 50 years been located to the east of the Bunker Hill mine. These include the Crescent, Sunshine, Silver Summit, Coeur, Galena, and Lucky Friday extending east-west about 12 miles. This string of properties is called "The Silver Belt", or, "The Silver Valley".
Most ore occurrences in the Silver Belt are located in an area defined by generally east-west trending structures; the Polaris Fault on the north and the Big Creek fault along the south portion of the Silver Belt. A prominent major fold, the Big Creek anticline, has been traced throughout the length of the Silver Belt area. In the Crescent Mine the Big Creek anticline is a major structure composed on two known folds. The Alhambra and Syndicate faults occur in the folds and are associated with ore occurrences in the Crescent and Sunshine Mines (source:report entitled, Geology of the Crescent mine By Norman Radford April 12 1973).
A significant number of veins are present in the Crescent, including the East Footwall, Hook, South, Lead, Steep Lead, Gray Copper, Parker, North, Chalchopyrite, Paramount, Wolverine, and Butler veins. Most production has occurred from the East Footwall, Hook and South veins.
Potential Geology
The property is underlain, by the most favorable conditions in the Coeur d'Alene district to yield ore discoveries. A combination of structures and favorable lithology at the contact of the St. Regis and Revett formations indicate potential for high-grade ore occurrences in portions of the mine that are still relatively unexplored and developed. The majority of ores in the Silver Belt occur in similar geographical areas.
The Company believes that there is near term mining potential for the Crescent Mine. Significant mining, milling and processing infrastructure are all located nearby as well there are reliable sources of power and water.
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