Tungsten deposits of Gila, Yavapai, and Mohave counties, Ariz.
Tucson, AZ: U.S. Department of the Interior, Bureau of Mines, IC 8078, 1961 Jan; :1-104
This report is one of a series covering the mineral resources of the Nation. It briefly describes most of the known tungsten deposits in Gila, Yavapai, and Mohave Counties, Ariz. Many of the descriptions are taken from the reports of previous examinations by Bureau of Mines engineers, and from Defense Minerals Exploration Administration files. Where a previous examination had been made, and an inquiry disclosed that little or no work had been done since that time, pertinent information from the report was used in this paper with acknowledgment of the source. However, the majority of the descriptions is from field examinations by the author. In the past 3 years (July 1956-May 1959) only necessary annual assessment work was conducted on nearly all the properties described in this paper. There was no active mining on any of the properties examined. Production figures are given for each deposit, where known, and for each county. Ore reserve estimates are made for the individual counties. The reader should bear in mind that most of the deposits are raw prospects and that virtually all ores were removed as they were encountered. At only three properties has there been any development work; most of the properties contained only shallow surface diggings. Tungsten mineralization was very sporadic and discontinuous in all deposits that were examined. Conventional sampling methods, other than bulk mining, often are unreliable; hence, very few samples were taken. An effort has been made to determine the position of the various deposits by section, township, and range, and to give accurate road directions to each property from a prominent landmark. All available maps have been used to make these determinations, but in unsurveyed areas it has been necessary to make approximate projections of subdivisions. The township and range numbers refer to the Gila and Salt River base and meridian. Search for new occurrences of tungsten minerals was greatly stimulated in this area by the Government purchasing program announced on May 10, 1951, wherein the Government agreed to purchase standard-grade tungsten concentrates at $63 per short ton unit. The program, with slight modifications, lasted until December 1956. By the end of August 1957, the price had dropped to $12.75 per short ton unit, duty extra. The word "ore" as used throughout this manuscript includes tungsten-bearing material too low in grade for exploitation except at very high prices. A look at the erratic price history will show why it is difficult to classify tungsten-bearing material. Field work for this report was done from July 1958 to May 1959.
Tucson, AZ: U.S. Department of the Interior, Bureau of Mines, IC 8078