Braving100-degree temperatures two miles down in South Africa’s East Driefonteingold mine, geologist T. C. Onstott sheds his shirt to collect microbe sampleswith biologist Duane Moser. Scientists once thought life could not be sustainedso far underground, but Onstott says evidence now suggests “microbes have beenhere for 2 billion years.”
Four scientists wearing coveralls and hard hats shuffle warily into asteel cage the size of a closet, cramming themselves against a dozenminers. The doors clang shut, and the bottom seems to drop out as theelevator plunges hundreds of stories down into the darkness--No. 5Shaft in South Africa's East Driefontein gold mine. Within moments theair becomes oppressive--hot and curiously thick. This is one of thedeepest excavations in the world, burrowing more than two miles towardthe center of Earth. At the bottom of the mine, radioactivity and heatfrom the planet's core raise the temperature of the stone in thetunnels to a searing 120 degrees Fahrenheit, and the atmosphericpressure is double that on the surface. Oxygen rarely exists naturallyso far underground, and only a constant rush of forced air from thesurface disperses poisonous methane and hydrogen seeping from the rock.Pumped-in jets of water help keep workers from slowly cooking to death.
Oxygendoes not exist naturally so far underground, and only a constant rushof forced air from the surface disperses poisonous methane and hydrogenseeping from the rock. Pumped-in jets of water help keep workers fromcooking to death.
As the elevator plummets, a miner turns onhis headlamp, revealing beads of sweat popping out on the face ofgeologist T. C. Onstott. The Princeton University professor is notscared. He pulls a water bottle from his knapsack and takes a long,slow swig. To him, the heat and claustrophobia are merely aggravation.Real worry here centers on what are euphemistically referred to asseismic events. So much rock gets dragged out of the mine each day thatthe earth around it resettles frequently. The resulting quakes spurrock bursts—high-pressure cave-ins that kill.
