The shaft work: The project to sink the shaft will cost $75 million and will be integral to increasing ventilation to WIPP’s underground work area, according to the DOE. When completed, it will be WIPP’s largest shaft at 26 feet in diameter, reaching 2,275 feet deep, and with passageways being excavated at the 2,150-foot level to match the rest of WIPP’s subterranean level that will eventually connect to the shaft.
As of the DOE's September 1 announcement, shaft excavation had reached 56 feet deep through the use of a mini excavator and crane-lifted buckets. The work is ongoing, 24 hours a day, five days a week, with an additional single shift on Saturdays.
The details: Before dirt can be excavated, a round steel cage is lowered into the shaft for workers to set explosive charges. Contractors drill small holes to place the charges; the explosives are detonated in a sequential pattern. The debris is then lifted out of the shaft by the buckets and the process is repeated.
Safety: Before the explosions occur, blast mats are placed over the top of the shaft and at a nearby location being excavated to install an angled piece of ductwork to feed air into the shaft. WIPP has implemented safety measures to alert motorists approaching the construction site, according to the DOE.
Going deeper: When the excavation reaches 100 feet below ground, a five-story multiplatform unit will be lowered into the shaft to continue the work. That unit has an excavating arm at its lower level and two holes in its main platform to allow buckets to be raised with excavated material and then lowered back down after emptying on the surface.