Bi-Metal Mine, Kingman, Kingman Mining District, Cerbat Mountains (Cerbat Range), Mohave County, Arizona, USAi

Regional Level Types
Bi-Metal Mine	Mine
Kingman	- not defined -
Kingman Mining District	Mining District
Cerbat Mountains (Cerbat Range)	Mountain Range
Mohave County	County
Arizona	State
USA	Country

Location and development. The Bi-Metal mine, also known as the McGuire mine, from the name of its owner, who lives near by, is in the northern part of the district, about 3-| miles from Kingman, close to the railroad, in the basal west slope of Kingman Mesa. The mine is developed principally by about 250 feet of open cut, 130 feet of tunneling, and a shaft 80 feet in depth. From the mouth of the tunnel the slope of the surface is about 30°.

Geology. The country rock containing the deposits is an altered and mineralized pre-Cambrian microcline granite: It occupies an area about 300 feet in diameter and locally seems to change into detrital masses, containing pebbles, cobbles, and bowlders of very dark to very light gray granite and schist ranging up to 2 feet or more in maximum diameter.

The structure, consisting of sheeting and cleavage, dips about 45° N., and has for the most part obliterated or obscured an older and more general north-south sheeting. Another system of jointing also 'dips westward about parallel with the surface slope, as shown in both the tunnel and the cut.

On the south the boundary of the mineralized area is marked by a dark-gray intrusive dike rock, which cuts the granite, contains inclusions or fragments of it, dips about 45° N. beneath the deposit, and is encountered in the bottom of the shaft. This dike rock is medium grained and consists essentially. of a groundmass of plagioclase prisms containing pale-greenish hornblende phenocrysts, of which the largest are about three-fourths of an inch in length. The solutions which mineralized the deposits may have accompanied or closely followed the intrusion of this rock. On the west, toward the railroad, the deposit is obscured by wash and debris. On the east the deposit seems to terminate above the mine at a point about where the slope steepens with overburden talus, but it may extend beneath this talus upward toward the top of the mesa and may possibly connect with a similar deposit about half a mile to the northeast.

Deposits. The values contained in the deposits consist essentially of fine-grained free gold. As seen in the face of the tunnel and the bottom of the shaft, both the granite and the dark dike rock carry considerable iron pyrites and, according to reports, but very little gold. The same is true of the mineralized granite on the surface to the north and south of the deposit. In the oxidized and mineralized zone, however, this pyrite, particularly in the granite, has weathered out and given rise to the hematite and other forms of iron that so brilliantly stain the rock, and has left cavities or receptacles in which the gold now contained in the deposit seems to have become concentrated. Wherever this oxidized rock is crushed and panned or
horned it yields a long string of fine, bright gold, and in some small gullies or lines of drainage within or at the border of the area, where further concentration by flowing water has taken place, several tablespoonfuls of mostly coarse gold, of which some of the largest nuggets contained about half a dollar each in gold value, are reported to have been panned. The gold is said to be of high grade, worth $19.50 an ounce.

The free gold to which the deposits owe their value seems to have been derived from a considerable thickness of overlying mineralized rock. As this overlying rock became disintegrated and was removed by erosion the fine gold liberated from it gradually worked into the underlying rocks in which it is now found. Below or outside of the oxidized zone of mechanical concentration probably only very low-grade ore occurs.

The mine is reported to have produced some gold, more than enough to pay for development, the gold being won principally by the use of-rockers.