Tucson, AZ: U.S. Department of the Interior, Bureau of Mines, RI 4275, 1948 May; :1-45
Intensive investigations of domestic manganese deposits were conducted by the Bureau of Mines and the Geological Survey during the earlier part of the war minerals investigations when there was doubt that the quantity of manganese needed to produce the greatly increased tonnage of steel demanded for war supplies could be obtained from its customary sources. Domestic deposits of ores that contain sufficient manganese for direct production of ferromanganese essential in steel manufacture are generally small, and the bulk of the supply is imported. One of the few, large deposits of low-grade manganese ore known in the United States is in the Artillery Peak district in southern Mohave County, Ariz. Manganiferous sediments underlie a very large area. Several large groups of claims, covering the most of the manganese-bearing ground, were assembled in 1929 and 1930. The greater part of this area was leased by the M. A. Hanna Co. in 1937. Investigations by engineers and geologists for this company revealed that the average content of manganese is very low; but that the Maggie Canyon area, about -180 acres, contains higher grade material. The company put down 28 vertical diamond-drill holes to explore this ground, under the direction of B. N. Webber, geologist. S. G. Lasky and R. G. Roberts, geologists of the Federal Geological Survey, made an intensive study of the deposit in 1939 and 1940 and reported that the Manganese oxide was deposited along with gravel, sand, and clay in alluvial fans and-playas within a basin between the Artillery and Rawhide Mountains. This material was swept down from the surrounding mountains by torrential rains from one side or another of the desert basin. The fans overlapped, and the playas migrated as the basin was filled. It is believed that the manganese, except for richer "hard ore," remains in its original state and locale. The "hard ore" occurs in a zone near the top of the manganiferous sediments. It is believed that this was enriched by redeposition of manganese dissolved and transported by percolating waters before the sediments were capped by lava flows and possibly to some extent since that time by infiltration along the basalt contact. In a deposit of this nature, the assumption that a given bed is continuous in thickness and grade for distances of 600 to 1,500 feet (the spacing of the holes drilled by the Hanna Co.) may lead to erroneous conclusions. Accordingly, the Bureau of Mines drilled 15 additional holes between those already drilled to get closer sampling and, a more reliable estimate of the available tonnage of manganese ore. Some experimental mining was done to determine the mining characteristics of the ore and the strength of the roof and to test the applicability of a room-and-pillar method of mining to this ore deposit. A lot of 2,500 tons of ore was shipped to the experimental plant at Boulder City, Nev., for metallurgical testing. The project was started in November 1940 and completed in June 1941. The factual data obtained are given in the body of this report. Drill-hole logs and a11 sample data are appended. The report also contains a brief discussion of metallurgical treatment of this ore. Concentration does not yield a metallurgical-grade product except at a prohibitive sacrifice of recovery. Two hydrometallurgical processes are available but have not been worked out to a conclusion on this ore. A combination of flotation and leaching may prove applicable to the ore.
Tucson, AZ: U.S. Department of the Interior, Bureau of Mines, RI 4275