History Of Pine Creek: A World-Class Tungsten Deposit

When prospectors discovered mineralized outcrops in Pine Creek Canyon in 1916, little did they know the site was destined to become one of the world's greatest tungsten mines. Located outside Bishop in California's rugged Sierra Nevada mountain range, the mine's development imposed unique challenges to the hardiest of mining men. In its early years, the Pine Creek operation was plagued by bad luck and poor timing. But through the perseverance of a dynamic group of mining personalities, it would gain world class status. Pine Creek tungsten supplied much of the defense needs of the United States during World War II and put the Bishop area on the map as a major contributor to the nation's stockpile of strategic metals. The mine's history was shaped by world politics, the ups and downs of metals demand and economic survival through technological innovations. In contrast to many mines, Pine Creek's workings went horizontally into and then up inside the mountains - nearly to the ridgetops. This resulted in the name "Mine in the Sky" being attached to the operation. The origin of Pine Creek's ore bodies is related to the emplacement of a portion of the Sierra Nevada batholith about 100 million years ago. During the intrusive process, granitic magmas engulfed overlying calcareous sedimentary rocks, flooding them with silica-rich hydrothermal fluids and metamorphosing them to skarn. The fluids also contained tungsten, molybdenum and copper. They precipitated as scheelite, molybdenite and chalcopyrite, respectively, during the metamorphic process. The ore-bearing skarns occur as near-vertical tabular pendants in the intrusive rocks. These were later exposed by the uplift of the Sierra Nevada mountain range and glacial erosion.