Geologic Map of the Maysville Quadrangle, Chaffee County, Colorado

The small mines and prospects along the Shavano fault zone north of Squaw
Creek (NE 1 / 4 , Section 4, T50N, R7E) and between Cree Creek and Lost Creek (NW 1 / 4 ,
Section 30, T50N, R7E) were active around 1910. These mines were primarily associated
with silicified fault breccias and quartz veins. The mines between Cree and Lost Creeks
have high silver associated with copper, lead and zinc mineralization and anomalous gold
(sample 05-854/855/857 with 82 ppm Ag, 1.02 percent Cu, 0.90 percent Pb, 0.48 percent
Zn and 0.257 ppm Au). The Bureau of Land Management LR2000 unpatented claim
records (BLM LR2000) indicated minor unpatented lode claims associated with these
mines and prospects from around 1959 to 1984.
The Blank mine is located along the Shavano fault zone in the range front area
between Squaw Creek and the North Fork. It includes a lower caved adit and upper caved
shaft, both with moderate-large sized waste dumps. There are also six caved adits with
small waste dumps along a northeast-trending 1,000 ft long zone, along the range front
and to the north of the main Blank mine workings. In addition, there is evidence on the
ground of a limited exploration drilling program in the Blank mine area. It includes five
short drill access roads and at least four drill pads that occur along a N35°E trend
extending for about 1,250 feet between the lower adit and upper shaft. A lack of
unpatented mining claims in Bureau of Land Management records in the Blank Mine area
indicate that the mining activity and exploration drilling predate the 1960’s and 1970’s.
Additional large mines in the northwest part of the Maysville quadrangle include
a cluster of mines and prospects in upper Lost Creek (SE 1 / 4 , Section 13 and NE 1 / 4 ,
Section 24, T50N, R6E and SW 1 / 4 , Section 18 and NW 1 / 4 , Section 19, T50N, R7E).
Crawford (1913, p. 280) mentioned the Lost Basin Group of 13 unpatented claims and
the Series Junction Group of 3 unpatented claims in upper Lost Creek. The Lost Basin
Group included the Lost Basin mine, which was a 600 ft long adit in 1910, on a quartzsulfide
vein hosted in the gneiss.
Crawford (1913) showed the locations of most of the main mines in the southwest
quadrant of the Maysville quadrangle. They include the cluster of mines (five adits) in
upper Como Creek (NW 1 / 4 , Section 7, T49N, R7E) with copper and zinc mineralization
(sample 05-106A/106B with 0.94 percent Cu and 1.69 percent Zn) associated with calcsilicates
and minor quartz veining. A group of mines (two adits and one shaft) and
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