What was a mining process that removed large quantities of earth.

Open-cast mining

Explanation:

The aftermath of open cast mining are pits (called quarries) on the surface of the earth where the surface soil has been removed / displaced to access the mineral deposits that are just close or at the surface of the earth. This type of mining results in environmental degradation because they disturb the biodiversity of the ecosystem in which the mining is taking place. Rehabilitation of the area is required after the mining has been exhausted to restore the initial environment.