AND OTHER FORMS OF MINING

The first part involves a relatively thin but powerful, high-velocity stream of water emerging from a jet under a high pressure. That stream of water can cut through rock, let alone coal and soft dirt, like a knife. (Such a water jet will, of course, kill anyone who gets in its way. That reminds us of radioactivity, which can also kill if it is intense enough. If only the anti nuclear fanatics were consistent, they would demand a total ban of all water.)

The method has been pioneered by the Soviets in several mines in Siberia, in the vicinity of their Hydrocoal Institute in Yubileynaya. They have licensed the process to Kaiser Resources, which uses it at a Canadian mine, and to a Japanese mining company.

The advantage of mining by water jet are increased productivity, virtual elimination of the dust problem, reduced danger of methane explosions, smaller capital investment than heavy machinery, and lightweight, easily moved equipment.

It does, however, require a sloping coal face for the water to run away to the slurry chambers, a strong roof and a stable floor resisting the heavy flow of water.

As for hydraulic transportation out of the mine, the leaders are evidently the West Germans; after 5 years of experimentation, Ruhrkohle A.G. has recently begun production in an all-hydraulic deep mining operation, which is expected to yield no less than 4,000 tons of coal a day.

The cutting of the coal by water jets is much the same as above, but the important innovation is the transport system, which hoists the coal slurry 3,000 ft to the surface; the intriguing part is a three chamber patented pipefeeder, that is three chambers connected to pipes carrying either clear water or coal slurry. The clear water and the slurry chase each other through a maze of piping and valves in which the clear water acts as an effetive piston to pump the coal slurry into the main exit pipe line. The high pressure pumps and valves are in contact only with the clear water never with the slurry, whose coal chunks would soon wear them out. This is done in a system of valves and plumbing that defies description in words but is not difficult to follow on the diagram published in Coal Ages Jan. 1978. (For details of the Soviet machinery described above, see the March 1978 issue.)

From coal to uranium mining: The new trick is not hydraulics, but chemistry. Uranium is leached out of subsurface ore bearing sandstone by adding chemical reagents to the ground water; the resulting liquor is then pumped to the surface processing plant, where the uranium is extracted by conventional methods. After further addition of reagents, the solution is recycled to the mineralized zone. When the ore zone has been depleted the ground water is restored to its original condition.

Wyoming Mineral Corporation is planning to use this type of "solution mining in northeast Wyoming about 10 miles northeast of Sussex and has applied for a source material license. A draft environmental statement has been issued by the NRC as the first part of slow motion process of licensing.

[More: ARC Neses Releasese 8 May 1978.]