Mining or in situ disintegration of hard material – Automatic control; signaling or indicating – Ore/rock interface determination during cutting
Patent
1991-07-15
1993-03-16
Bagnell, David J.
Mining or in situ disintegration of hard material
Automatic control; signaling or indicating
Ore/rock interface determination during cutting
7386441, 299 45, E21B 4908, E21C 3900, G01N 104
Patent
active
051938839
DESCRIPTION:
BRIEF SUMMARY
This invention deals with a control procedure for extraction plants and propulsion machines along a crevasse between coal and rock. More particularly, this invention relates to controlling reaming and advance machines along a cutting horizon between coal and rock, based on a cutting tool configuration affixed to a machine, fitted with a sensor able to differentiate between coal and rock areas, whose measuring values are transformed into actuating impulses, which guide the cutting tools to the cutting horizon. The invention also deals with a unit capable of executing this procedure. The invention relates specifically to the automation of coal extraction, preferably by using cutting machines, mainly roller loaders and continuous miners, but also extraction machines which process in ploughing motion as, for instance coal planes.
Depending on the design and format of the cutting tool layout in machines of this type, the unit can be directed to the cutting line between the coal lode and the rock with a control unit, and assume the desired position. The invention deals specifically with the control of those machines which enable automation of coal extraction from irregular or often geologically faulted lodes, whereby a sensor of robust material, and specifically designed to withstand conditions in underground mining, enables selection between coal lodes and adjacent rocks, obtaining control parameters enabling adjustments to be made to the tooling, so that the unit is automatically and speedily returned to the desired position.
The invention is based on a known technique. This has been implemented behind the cutters or tool retainer of a cutting extraction machine as a sensor, to ascertain whether the cutting line is within the coal lode or in the rock. The known technique uses radio-active isotopes as sensors; these have a short period of decay and a Geiger counter, which measures beams reflected between sender and receiver. The result depends on whether the dispersed rays penetrate coal or rock areas. It was however discovered that, due to the multitude of external influences on the intensity of reflected beams registered by the receiver, it was not possible to separate the typical coal and rock characteristics, since the static interference is much stronger than the differences in signals emitted from the coal or rock lodes.
Subsequent research has, with a few exceptions, concentrated on a combination of 4 sensors operating according to different physical methods, to compensate for inherent disadvantages and inexact measurements obtained from the various mechanisms by the 4-fold sensoring combination. However, the results obtained are not completely reliable. This applies specifically to the measuring chisel, radioactive beams, and a combination of visible and infrared light or sapphire laser beams. Measuring chisels used to capture the cutting force and transferring the results to the analysis unit also do not give exact information of whether the cut is made in coal or in neighbouring rock areas. Some lodes or some parts of a lode have areas in which the coal is a great deal harder than the adjacent rock formation. For instance, when analysing an adjacent area which is a combination of earth and root matter, the attempt at selection can in fact produce a false finding, resulting in incorrect control impulses which place the cutters or cutting units into the softer mineral, e.g. into the adjacent rock and ingrowth area.
In common with the known equipment or procedures for controlling extraction plants and propulsion machines along a crevasse between coal lodes and rock face, the invention also uses methods and laws known in physics, which however may differ in details, for simple direct and immediate selection between coal and rock lodes, thus enabling reliable control of the cutting equipment. This function is resolved by controlling reaming and advance machines along a cutting horizon between coal and rock, based on a cutting tool configuration affixed to a machine, fitted with a sensor able to differentia
REFERENCES:
patent: 4332301 (1982-06-01), Jonell
patent: 4502951 (1985-03-01), Koenig et al.
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