Tungsten Deposits in the United States

This database has been versioned where the new version supersedes the original database. Version 2.0 of Tungsten Deposits in the United States is available at https://doi.org/10.5066/P97NJLI4. Tungsten deposits have been mined in the United States since the late 19th century, but there has been minimal production of tungsten from mines in the United States since price crashes in the 1980's. Tungsten is necessary for strategic, consumer, and commercial applications. Due to its strength, hardness, high melting and boiling points, tungsten is used in wear-resistant applications, specialty steel and alloys, and electrical and chemical products. In 2017, the United States had a net import reliance as a percentage of apparent consumption of more than 50 percent for tungsten, and tungsten is now considered a critical mineral (Shedd, 2018). This data release provides descriptions of more than 80 of the largest tungsten mineral districts, mines, and mineral deposits within the United States. Tungsten most commonly occurs in the minerals scheelite, ferberite, and hubnerite. The majority of tungsten ore is derived from several types of mineral deposits, including skarns, veins, and porphyry deposits. This data release reports the largest 10 percent of U.S. deposits, or mines and deposits with greater than or equal to 215 metric tons of tungsten metal (30,000 short ton units of tungsten trioxide). These deposits occur in Alaska, California, Colorado, Idaho, Montana, North Carolina, New Mexico, Nevada, Texas, Utah and Washington. There are many smaller tungsten deposits and prospects throughout the United States in Connecticut, Maine, Missouri, New Hampshire, Oregon, Rhode Island, South Dakota, and Wyoming (Lemmon and Tweto, 1962). However, due to the resource cutoff established for this database, smaller deposits and prospects in those states are not included. Most tungsten prices and many tungsten statistics from other sources are quoted in units of tungsten trioxide (WO3). The short ton unit used in the United States is 1 percent of a short ton (20 lbs.). Tungsten trioxide is 79.3 percent tungsten by weight, therefore, a short ton unit of WO3 equals 20 pounds of WO3 and contains 7.19 kg (15.86 lbs.) of tungsten. The metric ton unit, which is used in most other countries, is 1 percent of a metric ton (10 kg). A metric ton unit of WO3, therefore, equals 10 kg of WO3 and contains 7.93 kg (17.48 lbs.) of tungsten (Shedd, 2015). The entries and descriptions in the database were derived from published papers, reports, data, and internet documents representing a variety of sources, including geologic and exploration studies described in State, Federal, and industry reports. Resources extracted from older sources might not be compliant with current rules and guidelines in minerals industry standards such as National Instrument 43-101 (NI 43-101) or the Joint Ore Reserves Committee Code (JORC Code). The inclusion of a particular tungsten mineral deposit in this database is not meant to imply that the deposit is currently economic. Rather, these deposits were included to capture the characteristics of the larger tungsten deposits in the United States, which are diverse in their geology and resource potential. Inclusion of material in the database is for descriptive purposes only and does not imply endorsement by the U.S. Government. The authors welcome additional published information in order to continually update and refine this dataset.