Page 146 - The Geology and Ore Deposits of Sierra County, New Mexico - Bulletin 10

MINING DISTRICTS 145
vein. The easterly outcrop is probably an extension of the Rich- mond vein that outcrops on the northeast slope of Richmond Mountain. The latter vein is known as the Bigelow No. 2. Both veins strike N. 20° E. and dip 80° NW.
The Bigelow No. 1 vein is developed by a 400-foot tunnel, which is reported to have exposed a mineralized seam the full length with a value of $3 to $80 per ton. Near the mouth of this tunnel a winze 25 feet deep is said to have exposed 12 to 18 inches of $45 ore in the bottom. Bigelow No. 2 vein is partly explored with a tunnel 150 feet long, said to be in good ore, and at the bottom of a 35-foot winze at the end of this tunnel, the vein is reported to be 3 feet wide and to average $19 per ton in free- milling gold.
MARY RICHMOND MINE
This property consists of two full-sized mining claims lo-
cated end to end, covering the outcrop of the Richmond or Mary Richmond vein on the northeast slope of Richmond Mountain. The dike along which the vein occurs is crossed by several minor faults and it has a number of branches, but it can be traced almost continuously from the monzonite porphyry cupola in Cop- per Flat to the wash at the southern end of the Garfield-Butler and Bigelow properties at the extreme southwest border of the area. Where the dike and its branches cross the top of the mountain, there is a remnant of a latite flow, which may be a local development of the dike system. In some places within this flow remnant, the course of the dikes may be traced by a fracture or series of parallel fractures that have become leached and iron stained as a result of oxidation ; in other places the flow rock ap-
pears to be of different texture and of finer grain along
of the dikes ; and in yet other places the writer was unable to detect any evidence that the dike rock was subsequent to the flow or that along the trend of the underlying dikes any planes of weakness had been developed in the flow rock.
The mine has been developed by three tunnels. These con- sist of an upper tunnel near the crest of the hill and 300 feet long, an intermediate tunnel at the level of the shaft collar, which is 860 feet in length, and a lower tunnel 160 feet below the collar of the shaft and 40 feet above the second level, which is 460 feet long. An inclined shaft follows down on the vein for 500 feet, and from it several levels have been driven. The first level is 100 feet below the collar of the shaft and extends 785 feet to the southwest and 40 feet to the northeast. The second level is 200 feet below the collar and extends 710 feet to the southwest and 200 feet to the northeast. The third level, at a depth of 300 feet, extends 320 feet to the southwest and 185 feet to the north- east. The water level is just below the third level, and the work- ings below it are flooded, but it is reported that there are two deeper levels totaling 1540 feet in length. The total amount of drifting on the vein in this mine is probably 3,800 feet, exclusive
,
the trend