The Gold Hill Mine complex (AKA Western Utah Mine and the
Clifton District) is located at the northern end of the Deep Creep Mountains in
western-most Utah. I first became
acquainted with the mountains and the mining area during my stint at the University
of Utah in the late 1960s. Later in life I had a vertebrate fossil collecting project
near the western edge of the Deep Creeks but located in Nevada (Nelson and
Madsen, 1987). I remember the area as
being one of the most desolate collecting sites that I worked, and made certain
that my student assistants remained in visual site of each other.
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Google Earth© image showing location of Deep Creek
Mountains (Deeps), Salt Lake City (SLC), with I-80 leading to Wendover (W).
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The Deep Creeks are located along the Utah-Nevada
state line about 30 miles south of Wendover, Utah/Nevada. Yes, Wendover, Utah, holds the parking lot
for the casinos at Wendover, Nevada. The
towns are about 120 miles west of Salt Lake City along I-80 in the Bonneville
Basin (home of Pleistocene Lake Bonneville and the much smaller Great Salt Lake).
The town site of Gold Hill (at the mining complex) is
still occupied by a small number of persons, and several dogs, which seem to
enjoy the solitude and their freedom.
The mine was opened in the mid-1800s and closed for gold mining in the
mid-1920s. During the period of WWI the
mines reopened to produce arsenic and in the 1940s (World War II) Gold Hill was
reopened to produce tungsten; however, during the mine’s lifespan silver, lead,
copper, lead, zinc were also produced.
The mineralization began at Gold Hill approximately 152 Ma as magma was
intruded into the overlying Paleozoic rocks---rich in silver, gold, arsenic,
copper, and lead (Robinson, 1993). A
second stage of mineralization commenced in the early to middle Tertiary
(perhaps 38 Ma) when magma again intruded into Mississippian to Pennsylvanian
sedimentary rocks---rich in silver, lead copper and gold In addition, extrusive
volcanic rocks, ~8 Ma, created some low-grade beryllium mineralization (Ege, 2005; Robinson,
1993). A much more extensive discussion
of Gold Hill may be found in the Blog Posting on January 3, 2015: Gold Hill, Utah,
Arsenates.
Gold Hill is famous among mineral collectors as
MinDat lists 102 valid minerals plus several varieties. It is the Type Locality
for Austinite and Juanitaite but the copper and arsenate (contain the AsO4
radical) minerals are often spectacular.
This small posting will document another addition to
my small Gold Hill collection, the rare lead aluminum arsenate hidalgoite [PbAl3(AsO4)(SO4)(OH)6]. The specimen, with what I identified as hidalgoite, was picked up from a dealer and
was noted as coming from the ?80’ level and is a product of weathering in the oxide
zone of metallic sulfide deposits (containing lead). Hidalgoite is sort of non-descript usually occurring
as a druze or spherulitic encrustation; however, at the type locality (Zimapan
Mining District, Hidalgo, Mexico) the mineral occurs as dense white masses. In some localities the mineral is colorless;
however, the specimens I have observed from Gold Hill are tan to orange to
shades of green. In addition, the Gold
Hill specimens are usually associated with “limonite” and secondary rust coloration
may hide the true color. Under the rust
the spherulitic encrustation of my specimen reveals microscopic crystals
(appearing translucent) tending to a tan color.
I tried to determine hardness but will settle for MinDat specification:
~4.5 (Mohs). The luster is rather dull/earthy and the streak is white.
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Spherulitic encrustation of tan to orange hidalgoite
composed of microcrystals; each spherule ranges from .3-.5 mm. I am uncertain
about the composition of the green mineral.
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I also found a story in a 2014 edition of The Salt Lake Tribune stating that the
BLM had given approval to Desert Hawk Gold Corp. to start up a cyanide
heap-leach mine in the Gold Hill area---extracting the gold and silver. I am uncertain if actual mining has
commenced.
REFERENCES
CITED
Ege, C.L., 2005, Selected mining districts in Utah:
Utah Geological Survey, Miscellaneous Publication 05-5.
Nelson, M. E., and J.H. Madsen, Jr., 1987, A new
Clarendonian (late Miocene) fauna from eastern Nevada: Contributions to
Geology, University of Wyoming, v. 25, p. 23-28.
Robinson, J.P., 1993, Provisional geologic map of
the Gold Hill quadrangle, Tooele County, Utah: Utah Geological Survey Map 140,
scale 1:24,000.