Arizona gold mine adventure

GOLD DEPOSITS Production: Yavapai County ranks first among the gold producing counties of Arizona. It has yielded approximately $50,000,000 worth of gold of which about 50.5 per cent was derived from copper mines, 39 per cent from gold and silver veins, 10 per cent from placers, and 0.5 per cent from lead and zinc mines.6 Most of the gold obtained as a by-product of copper mining has come from the Jerome district, where a large amount of the ores have yielded from 0.025 to 0.225 ounces of gold per ton. Distribution: As indicated by Figure 2, the gold districts are confined to the southern half of the county where faulting and igneous intrusion have been relatively intense. Types: The principal types of gold deposits in Yavapai County are exemplified in the Bradshaw Mountains and Jerome quadrangles where Lindgren 7 has classified them as follows: (1) Mesozoic or early Tertiary gold and gold-silver veins; (2) pre-Cambrian gold-quartz veins; and (3) pre-Cambrian gold quartz-tourmaline replacement deposits. 5 Jaggar, T. A. and Palache, C., Bradshaw Mountains Folio: U. S. Geol. Survey, Folio No. 126, 1925. Lindgren, W., Ore deposits of the Jerome and Bradshaw Mountains quadrangles, Arizona: U. S. Geol. Survey Bull. 782, 1926. Reber, L. E., Geology and ore deposits of the Jerome district: Am. Inst. Min. and Met. Eng., Trans., vol. 66, pp. 3-26, 1922. Lausen, Carl, Pre-Cambrian greenstone complex of the Jerome quadrangle: Jour. Geol., vol. 38, pp. 174-83, 460-65, 1930. 6 Figures compiled by J. B. Tenney. •7 Work cited, pp. 36-48 

GROOM CREEK DISTRICT The Groom Creek district is mainly in the vicinity of upper Groom Creek, an intermittent stream that flows southwestward to join the Hassayampa at a point about 5 miles south of Prescott. Within its drainage area, which ranges in elevation from 5,400 to more than 7,000 feet above sea level, are several silver gold-bearing quartz veins which have been worked intermittently for many years. In this area, water and timber are relatively abundant, but operations during winter are sometimes hampered by snow. The principal rocks are pre-Cambrian sedimentary schist, intruded by stocks and dikes of granodiorite and diorite. The quartz veins tend to be narrow and lenticular. They probably belong to the mesothermal type but have been worked mainly above the sulphide zone. The Midnight Test (National Gold), Empire, King-Kelly-Monte Cristo, Victor, and Home Run properties are in this district. When visited in January, 1934, only the Midnight Test mine was being actively operated. NATIONAL GOLD (MIDNIGHT TEST) MINE The Midnight Test mine, held by the National Gold Corporation, is on the northwestern slope of Spruce Mountain, at an 20 Abstracted from Lindgren, W., work cited, p

BIGBUG DISTRICT28 The Bigbug district is on the northeastern slopes of the Bradshaw Mountains. It ranges in altitude from 7,000 feet, west of Bigbug Mesa, to 4,500 feet, in Agua Fria Valley. The western portion is timbered and fairly well watered, while the lower dissected pediment or foothill belt is rather dry and brushy to open country. This area is made up of schist, intruded in places by diorite, granodiorite, granite, and dikes of rhyolite-porphyry. The schist is mainly of sedimentary origin, with many quartzitic beds, but contains also some igneous members. It is intruded on the west by the Mount Union belt of granite, and southwest of McCabe, by a stock of granodiorite. These relations are shown on the geologic map of the Bradshaw Mountains quadrangle, by T. A. Jaggar and C. Palache. 2 !J Basalt flows of post-mineral age form Bigbug Mesa where they rest upon a late Tertiary or early Quaternary pediment. Elsewhere in the district, this pediment has extensively dissected by post-basalt erosion. Lindgren has classified the ore deposits, other than placers, as (1) Pyritic copper deposits, such as the Blue Bell, HackButternut, and Boggs; (2) Pre-Cambrian quartz veins, such old Mesa, near Poland; (3) The Iron King gold-silver repl~lCem{mt deposit; (4) Later veins, probably connected geneti with rhyolite-porphyry dikes, mainly near Poland and Prov- ……. U.U.