Blue Bird Mine (Bluebird Mine; Zilla Mine; Twin-S Mine; Cumberland Mine; Thornewood Mine; Blue Bird Silver Mining Co. property), Copper Creek (Copper Creek Canyon), Bunker Hill District (Copper Creek District), Pinal County, Arizona, USAi

Regional Level Types
Blue Bird Mine (Bluebird Mine; Zilla Mine; Twin-S Mine; Cumberland Mine; Thornewood Mine; Blue Bird Silver Mining Co. property)	Mine
Copper Creek (Copper Creek Canyon)	Creek
Bunker Hill District (Copper Creek District)	Mining District
Pinal County	County
Arizona	State
USA	Country

A former underground Pb-Ag-Cu-Au-Zn-Mo-V-Fe mine located in the SE¼ sec. 2, T8S, R18E, 1 mile NE of Copper Creek post office, at an altitude of approximately 4,600 feet, on private land. Located in a South-sloping gulch tributary to Copper Creek. Owned by the Copper State Metals Mining Co. (1910-1914), which operated it as the renamed Cumberland Mine; then acquired by Mr. George Young who operated it in a small way (1914-1918); finally, during the period 1918-1930, it was operated successively by Blue Bird Silver Mining Co.; Twin-S Mining Co.; and the Field Mining Corp. Intermittent production continued and during 1939-1940 Blue Bird Mining Company mined it. In 1947 Bluebird Mines, Inc. reopened the mine. It closed in 1948. Also known as / designated: Unpatented claim MS 3526, Twin-S Mining Co. property; OPatented claims MS 4123 Red Bird; Fields Mining Corp. property.

The Blue Bird vein occupies a fissure zone in granodiorite. This ore zone is 213.3 meters long, 1.52 meters wide, with a depth-to-bottom of 163 meters, striking N40º to 60ºE. and dipping 80º to 85ºSE, with a plunge of 45NE. It is from 2 to 5 feet wide and consists of numerous sub-parallel fissures en echelon. In many places it has been intruded by small andesite dikes. Galena and tetrahedrite are the major ore minerals. Ore pinches and swells. There are barren areas.

Two distinct mineralized bodies occur in the vein. The main orebody, containing sulfides of Pb, Ag, Cu, and Fe, has been followed from surface to the 535 level and found to pitch 45ºNE. The other body, containing wulfenite of sub-commercial grade, apexes near the 335 level.

The main ore zone consists of sulfide-filled fractures cutting quartz, altered granodiorite, and andesite. In many places, sulfides occur along the fault which forms the footwall of the vein, but commonly stringers of galena follow fractures crossing the vein. Along single fractures the sulfide zones are an inch or less in width, but, where several of the fractures meet, widths of 3 to 9 inches (7.5 to 22.5 cm) are common. The ore pinches and swells along the individual fractures, and within the orebody are barren areas. Crushing has occurred within the vein, and these areas are barren. Towards the horizontal limits of the orebody, the amount of sulfides diminishes, although the vein continues. In general, only slight oxidation of the Fe & Cu minerals is apparent in the main vein.

The mineralized portion of the vein NE of the sulfide body on the lower levels occurs within a breccia that has been followed on the 535 level for at least 200 feet. Angular to rounded, altered blocks of granodiorite, 4 to 8 inches (10 to 20 cm) across, surrounded and cemented by quartz, limonite, and psilomelane, occur within a zone 4 to 6 feet wide. Small dikes have intruded the breccia. On the 335 and 435 levels, the breccia zone is adjacent to the sulfide body, but on the 535 level about 100 feet of fresh granodiorite separates the two bodies. A fault containing 2 to 4 inches (5 to 10 cm) of gouge, quartz, and limonite cuts the breccia zone and connects with the galena-bearing fissures of the sulfide body. The wulfenite on the 535 level occcurs with limonite, partly filling open spaces within the quartz network. Psilomelane is present as stains on quartz and as stringers generally less than ¾ inch wide, and cements brecciated blocks of granodiorite.

The copper content of these ores increases with depth. The granodiorite wall rock show partial alteration for a few feet from the vein to kaolin, sericite, and chlorite. Small grains of pyrite are disseminated in the granodiorite. Alteration of rock fragments within the vein is more intense than that within the walls.

Workings include 1 vertical shaft, 7 levels, now mostly inaccessible; 1 open stope (see Arizona Bureau of Mines Bull. 158: 64, figure 15 for plan of workings). The workings achieved a depth of 163.07 meters and a length of 1524 meters. This mine was worked intermittantly during 1914, 1918-1930, 1939-1940, 1947-1948. From 1939-1940 the mine mill concentrated capacity of 25 tons per day. In 1947-1948, a 50 ton capacity concentrator was in operation and 598 tons were treated. Production prior to 1926 estimated at $150,000, mainly Pb & Ag (period values). During 1926-39, output of Pb-Ag-Cu was approximately $350,000 (period values). 598 tons of ore mined in 1948 yielded 31,200 pounds of Pb, 2,100 pounds of Cu, 1,085 oz. Ag & 3 oz. Au, valued in all at $6,021 (period values).

Other Databases

Link to USGS MRDS:	10039466

Other Regions, Features and Areas containing this locality

References