Mining or in situ disintegration of hard material – Processes
Reexamination Certificate
2002-06-24
2004-01-06
Shackelford, Heather (Department: 3673)
Mining or in situ disintegration of hard material
Processes
C299S013000, C299S069000, C299S030000, C299S095000, C102S321000
Reexamination Certificate
active
06672673
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an ore pass inspection system that allows imaging of the ore pass in an underground mine. This ore pass inspection system is especially useful in cases of hang-ups or blockages within the ore pass. This inspection system can also be used to help clear such hang-ups or blockages.
BACKGROUND OF THE INVENTION
An ore pass is a generally vertical or near-vertical passage excavated between at least two levels in an underground mine. The levels occur at different vertical displacements in the mine. The vertical distances between such levels, and thus the vertical extent of the ore pass, may range up to hundreds of feet or even more. Such ore passes provide a passageway for delivering mine products (i.e., ore, coal, and the like) from a higher level to a lower level within the mine. Generally, the lower level contains ore carts, carriages, trams, or other transport devices which allow the mine products to be removed directly or indirectly out of the mine. In some cases, the lower level can serve several higher levels through the same or different ore passes.
The interior walls of an ore pass may contain surface structures ranging from smooth to very rough. The surface features may depend, for example, on the geological structures traversed by the ore pass, the nature of the mining tool or apparatus used in boring out the ore pass, and similar factors. Additionally, the cross-sectional dimensions of such ore passes may vary. Likewise, the sizes, shapes, and structures of the mining products being transported via the ore pass may vary greatly. Thus, from time to time in a given ore pass, the mining products may “hang up” within the ore pass. The just mentioned factors contribute to the likelihood of such hang-ups and blockages within ore passes. The likelihood of such blockages will be significantly higher in some cases (e.g., rough ore pass surfaces, “bottlenecks” within the ore pass, non-vertical passageways within the ore pass, large and irregularly shaped mine products). Once a hang-up or blockage occurs, the piling up of additional mine product on top of the hang-up often packs the blockage more tightly and makes removal of the blockage more difficult.
Clearing an ore pass hang-up or blockage presents significant safety concerns. For example, a miner at the lower end of the ore pass attempting to remove the blockage could be exposed to any material dislodged from the hang-up. If the miner is standing at the bottom end of the ore pass, and directing a disrupting force upwards into the ore pass toward the hang-up, any sudden rush of ore attending a successful clearing operation may trap the miner and cause serious injury or death. As of the time of this invention, there have been at least five ore pass-related fatalities in the preceding five years in the United States, and a far larger number of ore pass hang-up-related injuries.
The United States has about 100 to 200 mines containing working ore passes. Any given mine may have one or more ore passes; some mines have upwards of 10 or even more ore passes. Depending on the factors identified above, the frequency and likelihood of an ore pass hang-up may vary considerably. In some case, an ore pass may become hung-up only rarely in other cases, it may be an almost daily occurrence. Likewise, and for similar reasons, the degree of difficulty in clearing such a hang-up varies widely. Numerous techniques to remove the blockage have been developed. These include, for example, delivering blows to structures adjoining or related to the ore pass; placing a small blasting charge either just inside the ore pass or as close to the blockage as possible using, for example, a long pole; or propelling the explosive charge as a ballistic slug toward the location of the hang-up. Alternatively, a separate long hole may be drilled from below (mobilizing a drill rig in the passageway beneath the blockage) in order to deliver a blasting agent through the drilled hole into the hang-up. Clearly, the latter tactic is both time consuming and expensive. In some cases, the mine operator may choose to abandon the blocked ore pass and bore a new one.
U.S. Pat. No. 4,930,595 discloses a method of remotely determining the profile of a subterranean passage within a mine using an instrument pod that can be moved along the passage. The pod includes a rangefinder for determining the distances from a defined longitudinal axis of the pod to multiple points on the internal wall of the passage and providing an output signal representing the profile of the passage. A clinometer is used to indicate the orientation of the pod in the passage. The signals are transmitted to a remote location and provide a visual representation of the profile of the passage at a given location. As the pod is moved, successive representations at different locations are obtained. The pod is preferably also provided with a television camera and lighting so that the wall of the passage can also be visually inspected. Since the pod moves by gravity, it is generally intended for use by being lowered down the passage; in some cases, the pod can be pulled up the passage.
U.S. Pat. No. 4,023,862 provides a coal mining method wherein the coal seam is disintegrated by utilizing a jet of hot oil under pressure. Since an operation can be remotely controlled in a deep mine shaft, exposure of mine workers can be minimized. The method further reduces the amount of coal dust produced and, thus, reduces the risk of dust explosions. A TV camera can be mounted on the mining machine for transmitting a picture of the operation to the surface so that appropriate guiding signals can be transmitted to the machine.
U.S. Pat. No. 4,708,395 discloses a method and apparatus for hydraulically mining a coal seam using a monitor and a hydraulic jet powered by high pressure water. The monitor includes means for remotely positioning the jet vertically and horizontally so that the jet can be aimed at any location within the zone of a mine face being mined. This system is especially useful in hazardous locations within a mine (e.g., unstable areas where the risk of roof falls is significant).
U.S. Pat. No. 5,069,108 discloses a blasting device for unblocking ore passes, backfill raises, mine draw points, or other near vertical raises where rocks or other materials normally fall freely but may get blocked during use. The device includes a propulsion unit including an air chamber mounted at the end of a hollow tube with an inlet for receiving pressurized air and at least one outlet for allowing compressed air jets to exit downwardly from the air chamber to propel the propulsion unit upwardly. A reservoir is mounted on the propulsion unit and adapted to hold an explosive charge and an igniter which can be remotely activated.
As those skilled in the art realize, it is generally more effective to attack a blockage from below. But efforts from below place the workers at maximum risk since once the blockage is clear, the hung-up materials will, of course, continue their fall through the ore pass. Even if the blockage is not completely cleared, material dislodged from the blockage place workers located below at significant risk.
Thus, there still remains a need for an apparatus and method that integrally permits placing the apparatus in a location immediately under a hang-up in an ore pass in order to clear the hang-up while minimizing the risks to the operator. There additionally remains a need for an apparatus and method that substantially eliminates guesswork in placing a device to clear an ore pass hang-up, and that employs an image based guiding mechanism to direct the apparatus to a preferred position for clearing a hang-up. There further remains needs for method for clearing blockages and for an apparatus and that is reusable. The present invention addresses these unresolved needs.
SUMMARY OF THE INVENTION
The present invention discloses an apparatus for clearing a material hang-up in an essentially vertical shaft having walls which is used for moving material from a higher level t
Dorrington Christopher
Garvey Travis
Maricich Peter
Miller Arthur L.
Schmitz Paula
Kreck John
Shackelford Heather
The United States of America as represented by the Department of
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