SALT LAKE CITY, Utah (AP) — A Utah copper mine will provide a new North American source of the critical mineral tellurium, which is used in photovoltaic solar cells. Tellurium is one of the least common elements on Earth and is eight times rarer than gold. Up to 20 tons of tellurium a year will be recovered as a byproduct of the copper mining at the Bingham Canyon Mine and will supplement U.S. tellurium production from a mine in Amarillo, Texas. When alloyed with elements such as cadmium, tellurium forms a compound with enhanced electrical conductivity. It’s used in solar panels and night vision goggles.