Even before an atomic bomb leveled Hiroshima, scientists dreamed of the day when nuclear explosives might be used to build, not to destroy. They talked about moving mountains with nuclear blasts, digging harbors and tunnels, constructing canals. Huge oil caches, they said, could be recovered with underground explosions.
In 1957 the U.S. Government finally got to work on Project Plowshare,* a program for developing the peaceful uses of nuclear explosives. Last week, after a 2½-year moratorium on testing, the first nonmilitary nuclear bomb test ever conducted in the U.S. rocked the flat floor of the New Mexico desert with a mighty underground blast. And what had begun as a bright scientific dream almost turned into a nightmare. For a few minutes, minor accidents and miscalculations suggested disaster.
Man-Made Quake. Scientists had worked hard to make a success of Project Gnome, an offspring of Plowshare. An elevator shaft had been sunk 1,216 ft. below the New Mexico desert, just 25 miles from Carlsbad. At the bottom of the shaft (see diagram), a horizontal tunnel had been cut through 1,116 ft. of rock salt, silt and clay stone. The plan was to explode a 5-kiloton nuclear charge at a crook in the end of the tunnel. If all went according to theory, the tunnel would collapse; some 1,200 ft. underground, a huge cylindrical, salt-lined cavern would be formed. Conceivably, heat from the blast could turn moisture to steam for the production of electrical power. In the future, such atom-produced power might even be economical enough for general use.
Also programmed for the $5,500,000 blast were some other experiments. Such elements as tritium and americum were to be exposed to nuclear particles released by the explosion; scientists hoped to recover the elements in radioactive form. "Wheels" which revolve at high speed and contain various elements on their rims were lowered into the shaft in the expected path of neutrons; scientists planned to study the wheels, find out how the neutrons affected the elements. At many spots around "ground zero" (the point directly above the blast), instruments were set to measure shock waves, temperature and radioactivity. Around the globe, seismologists monitored the countdown on short-wave radio and then watched their instruments to record the effect of the man-made quake. There was a cache of TNT near by, to be detonated five minutes after the blast. Instruments were to compare the wave from the underground nuclear blast with the wave from a known quantity of TNT. Project Gnome's big blast was easily the most heavily instrumented U.S. nuclear test in the short history of the atom.