The deposit is located in an area of the Great Basin Desert in eastern Nevada and could contain almost two million metric tons of tungsten. Mining company 3 Proton Lithium (3PL) wants to develop the site, but around a third of it is located in lands reserved for NASA to use for calibrating Earth-observing satellites. The pristine wilderness allows the space agency to fine-tune instruments onboard these spacecraft to ensure they make accurate measurements. NASA has used the area, known as Railroad Valley, for this purpose for at least 33 years. By contrast, China’s mines produced 67,000 metric tons of tungsten in each of those years, accounting for almost 80 percent of global production.