The East Boulder Mine was initially permitted in 1992. The Environmental Impact Statement and Hard Rock Mine Impact Plan for the East Boulder Mine were updated in 1998. Construction of the East Boulder Mine began in 1999. Two 3.5-mile (5.6-kilometer) portals were bored to access the ore. Most of the major above-ground facilities and infrastructure were completed in 2000, and commercial production began in 2002. The East Boulder Mine area extends nearly 14,000 feet (4,300 meters) horizontally by 2,000 feet (610 meters) vertically.