A specialized method for excavating mine shafts through heavily waterlogged strata or quicksand. The shaft is sealed with an airlock and pressurized, forcing the water back into the surrounding rock so miners can excavate dry ground and install cast-iron or concrete tubbing. Once the watertight lining is secure, the pressure is normalized.
Heard on the job
The water table was too high for standard pumping, so the engineers opted for the Triger process to get the shaft down to bedrock.