Abstract:

On Federal land, Gilsonite is presently being extracted by two major mining companies using simple, non-mechanized but practical mining methods. Typically the 1-6-ft (.3-2-m) wide vertical veins are extracted leaving a 35-ft (110-m) thick rich layer near the surface (crown pillar) and other barrier pillars 10-30-ft (3-10-m) thick between 100-ft (30-m) tall stopes. Mining has historically been conducted in a descending order using a 10-ft (3-m) drift and slopes while systematically supporting the stope walls with timber.

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