CALORIES WITHOUT THE COAL

At our last report, researchers of the Univ. of California's Lawrence Livermore Lab had rubblized coal deposits by detonating explosive charges at Hanna, Wyo., before burning it underground in a controlled chemical reaction to yield gaseous fuel at the surface. Recently these researchers completed a test using another method at Hoe Creek, Wyoming.

They drilled a 130-foot borehole by directional drilling horizontally across the bottom of a 200 ft thick coal seam. Then they set the coal on fire with an electric lighter and pumped air down for six days to make the flame burn along the bore hole. Next, they switched to a rich mixture of pure oxygen and steam. This was pumped down for 48 days (through Oct. 10, 1979), the longest "steam-oxygen" burn on record.

The resulting gas, a mixture of methane, hydrogen and carbon monoxide, is a fuel that can be used for direct heating, the generation of electric power, or any other industrial process. The experiment produced some 200 million cubic feet of the gas by burning almost 4,000 tons of coal underground.

In a previous experiment at Hoe Creek in 1977, only air was pumped down and produced gas with a heat value of 108 BTU per cft. The present experiment almost doubled this to 210 BTU/cft. This is below high-quality producer gas (which ranges from 50 to 500 BTU/cft, and ranks itself well below natural gas with about 900 BTU/cft); but then, producer gas is made in a coke furnace with the concentrations of the fuels completely under the manufacturer's control, and in any case, it costs more BTU's than the difference to mine the coal and transport it to the furnace.

[Source: LLL news release of Oct. 30, 1979.]