Mining of both types of salt deposi

Mining of both types of salt deposit is similar. The method of
mining is called "room and pillar“ because the salt is excavated
by blasting and loading out a series of rectangular entries and
cross cuts. Rectangular pillars in a checkerboard-like pattern,
typically 35% to 50% of the original salt, remain to support the
mine roof. Rooms in bedded salt mines are 10 ft to 45 ft high,
while rooms in domal mines can exceed 100 ft in height