WATER JET CONFERENCE - Waterjet Technology Association

Is water jet cutting the next major innovation in mining? The last major
breakthrough in coal mine cutting technology was in the 1940's when the introduction of
tungsten carbide significantly increased the life and cutting ability of mechanical tools.
Recent studies with water jet cutting indicate that significant improvements can be made
to the cutting process when using this technology (Kramer, 1980; Souder and Evans,
1982).
Using conventional cutting technology, today's mining machines such as the
continuous miner, longwall shearer, tunnel boring machine, and roadheader have
generally been optimized with respect to their cutting ability in relation to their size and
weight. All of these machines use thrust and torque, which is a function of the machine's
weight and tractive effort, to provide the forces required for cutting. Most attempts to
increase thrust and torque have resulted in increased machine weight and size thereby
decreasing the machine's maneuverability and productivity. What is needed is improved
cutting technology to substantially increase machine productivity.
The potential for a major advance in cutting technology has been demonstrated
using water jets or water jet assisted cutting systems. Experiments have been conducted
in a wide variety of rock types and coal, both in the laboratory and underground, that
have demonstrated that not only can substantial improvements in cutting performance be
achieved but also substantial improvements in health and safety. These improvements
include: considerable reductions in dust during the cutting operation; reduction in fines;
elimination of frictional sparking and ignitions; and in the case of water jet assist cutting,
significant reductions in pick forces and increased pick life (Souder and Evans, 1982).
One can clearly see the potentials of water jet cutting in U.S. coals. The time is
ripe for an enterprising equipment maker and an entrepreneurial coal company to
collaborte in a successful field trial that ignites a bandwagon of water jet coal cutting
applications.
ACKNOWLEDGEMENTS
The authors are indebted to Mr. Ernest A. Curth and Mr. John Kovac, U.S.
Bureau of Mines, for their comments on an earlier draft and to Dr. D.A. Summers,
University of Missouri-Rolla and Dr. E.R. Palowitch, consultant, for many helpful inputs.
REFERENCES
Frank, J.N., Fogelson, D.N. and Chester, J.W., 1972, "Hydraulic Fragmentation in the
U.S.A.," Proceedings of the First International Symposium on Jet Cutting Technology.
Coventry, England, Session E4, pp 45-61.
Kramer, T., "Investigation of High Pressure Water Jet Cutting in Coal Winning," June
1980, Fifth International Symposium Jet Cutting Technologies, Hanover, Germany, pp
313-326.
Schwarting, K., Goris, H., Kramer, T., and Wille, G., 1981, "Development and
Underground Testing of a Winning Method with High Pressure Jets," Gluckhauf, Vol.
117, No. 23, pp 1527-1531.
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