Surface mining techniques have been employed at Mountain Pass since inception of commercial Lanthanide operations in 1951. Mining is carried out with 85-ton haul trucks and 13-cubic-yard front-end loaders. Geological projections, ore-body mapping, blast hole cutting assays and metallurgical testing provide necessary input to ensure consistent, on-grade ore production. A stripping ratio of approximately 8 tons of waste per ton ore yields an 8.5% ore grade feed to the mill.

Today, approximately 50 years after inception of mining at Mountain Pass, the pit measures approximately 1500 feet in diameter and 500 feet in depth.