A bank cubic yard, or BCY, is the calculation or measurement of 1 cubic yard of earth or rock in its natural state before it is removed from the ground. The volume measurement is commonly used in the mining and construction fields.
In comparison, a loose cubic yard, or LCY, is the measurement of the soil after excavation. When soil is removed from the ground, it is no longer compact, and it further swells with the addition of air. This means that 1 bank cubic yard of earth removed from the ground will almost always amount to more than 1 loose cubic yard of the same substance.