Geology & Ore Deposits of the Getchell Region, Humboldt County, Nevada: Twin Creeks, Getchell, Pinson & Preble Mines


The Geological Society of Nevada is pleased to present another field trip to the Getchell Gold
Region of north central Nevada. While GSN has a history of presenting trips to these mines starting
in the 1980s, each time we visit an area we are able to take a fresh perspective on the geology
and to watch the evolution of the remarkable mineral exploration and mining in the district.
This trip will be no exception. Our trip will tour Twin Creeks Mine, owned by Newmont Mining
Company, the Getchell Mine, owned by Placer Dome, and the Pinson and Preble Mines, owned by
Pinson Mining Company, a partnership of Homestake Mining Company and Barrick Holding
Company. We will also take time to discuss the complex and poorly understood regional geologic
history of this area. The mines and geology are shown on the regional map on page 71.
Mining activity in the Getchell region began with tungsten and gold exploration in the late 1800s.
The Golconda district was organized in 1866 and saw gold production in 1909, and the Potosi
district was organized in 1874, although gold was not discovered there until 1934. Getchell Mines
Inc. was formed in 1936 by U.S. Senator Noble Getchell, and some of the earliest oxide gold mining
in Nevada began there in 1937. During World War II, the Getchell Mine produced tungsten,
arsenic and molybdenum concentrates for the War Board. Claims for the Ogee and Pinson Mine
were staked in 1945 and subsequently developed. Relatives of Clovis Pinson still live in the valley
today. Getchell Mine was one of the first gold mines to develop autoclave technology for roasting
sulfide ores in the 1960s and 1970s, although significant economic production didn’t occur until
the 1980s. The Preble Deposit was discovered in 1972 by Cordex, early in the development of
bulk mining technology for low grade disseminated gold deposits.
Renewed gold exploration interest in the 1980s led to discovery and development of many new
resources in the area. Pinson began gold production in 1980 and has produced nearly 1,000,000
ounces to date. Getchell operations were reinvigorated by First Miss Gold in the early 1980s,
which led to the discovery and development of significant resources, now totaling as much as 9.4
million contained ounces of gold. The late 1980s gold rush precipitated the impressive discoveries
of the Chimney Creek and Rabbit Creek deposits, now consolidated into the Twin Creeks
Mine, which produced more than 750,000 ounces of gold in 1999. The proven and probable
reserves at Twin Creeks are currently over 8.6 million ounces. All together, the region along the
eastern range front of the Osgood Mountains likely hosts nearly 20 million ounces of gold.
Exploration is actively underway, and there is no reason to think that all the resources of the
region have been uncovered.
While the Getchell region has the second largest district-wide gold endowment in the state, it
probably has the most poorly understood regional geologic history. The relations between
Paleozoic units in the Osgood Mountains and elsewhere in Nevada are not understood. The structural
and tectonic setting of the Paleozoic rocks in the Osgood Mountains contrasts with those of
similar age elsewhere in Nevada. Controversy over the tectonic origins and geologic relations of
the area have been debated for 40 years. New ideas involving the accretion and dislocation of terranes
will be presented and discussed to further stimulate our thinking of the geologic history of
the region, and the origins of the world class mineral deposits hosted in these rocks

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