By A. H. KOSCHMANN and M. H. BERGENDAHL - USGS 1968
Catron County, which was separated from Socorro County in 1921, lies along the western border of the State, and ranks second, next to Grant County, in the production of gold in the State. Through 1959 it had yielded about 362,225 ounces of gold, of which 362,132 ounces was produced through 1950 (Martin, 1953, p. 645). During 1904-42 about 40 percent of all the silver and 25 percent of all the gold produced in New Mexico came from this county.
Except for small shipments of tin concentrates during 1940-43, the entire metal output of the county came from lodes in the Mogollon (Cooney) district in the southwest corner of the county, about 85 miles northwest of Silver City, the nearest railhead (Anderson, 1957, p. 31-32).
A sergeant named James C. Cooney, who was stationed at Fort Bayard, staked the first claims in the Mogollon (Cooney) district in 1875, but hostile Apache Indians prevented the shipment of ore until 1879. Intermittent Indian raids continued to harass the miners until the defeat of Geronimo in 1885. The mines were then developed rapidly; by 1905 the district had produced $5 million worth of copper, silver, and gold (Ferguson, 1927, p. 34).
By 1924 many of the original mines, including the Cooney, were closed because of depletion of the surface ores. Exploitation of the lower grade sulfide ores at depth demanded large-scale mining methods, and as a result, most properties were consolidated under the Mogollon Mines Co. The district was moderately active through 1946, but it was virtually idle from 1947 through 1959. The entire gold production of Catron County through 1959 came from the Mogollon district.
The Mogollon Range, in which the ore deposits are found, is composed of a section more than 8,000 feet thick of Tertiary lavas and pyroclastic rocks interbedded with subordinate amounts of sandstone and conglomerate. The ubiquitous Gila Conglomerate of Pliocene or Pleistocene age unconformably overlies the older Tertiary rocks. The rocks are cut by a network of normal faults of several ages (Ferguson, 1927, p. 5-25).
The ore deposits are in silver and gold-bearing quartz veins along faults. The composition of the wallrock apparently exerted little influence on the content of the veins; however, the fracturing characteristics of the wallrock controlled the size and altitude of the ore bodies (Ferguson, 1927, p. 44-45). Calcite, quartz, and fluorite are the principal gangue minerals; adularia is present, but it is rare. The primary metallic minerals in the veins are pyrite, chalcopyrite, bornite, chalcocite, sphalerite, galena, stromeyerite, and probably tetrahedrite.
Silver in the form of argentite is the valuable component in most veins. The upper parts of the veins are oxidized to irregular depths and contain limonite, malachite, azurite, chrysocolla, cerargyrite, and sparse native silver and native gold (Ferguson, 1927, p. 38-50).
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