Conveyors: power-driven – Conveyor section – Endless conveyor
Reexamination Certificate
1997-07-02
2001-05-29
Valenza, Joseph E. (Department: 3651)
Conveyors: power-driven
Conveyor section
Endless conveyor
C198S840000, C198S841000
Reexamination Certificate
active
06237753
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
This invention relates to conveyor apparatus and method for use in mining operations. In one aspect, this invention relates to mining conveyor apparatus and method for performing continuous haulage in a mine.
2. Background
Mining operations today use conveyor apparatus extensively to remove material, e.g., such as coal or ore, from the mine. The conveyor apparatus improves productivity over those methods which do not have “continuous” means for removing the mined material from the mine face.
U.S. Pat. No. 4,031,997, issued to Nelson, discloses a mobile cascade conveyor system, but nevertheless presents a background of the invention describing parallel room mining with intermittent/discontinuous or continuous methods for carrying coal from the continuous miner.
Continuous miner machines work at removing the mined material, e.g., ore or coal, from the mine face and thereby extend into the mine and away from the conveyor or other means for removing the material produced by the continuous miner. After the continuous miner extends so far, the miner must be retracted away from the mine face to install or construct roof supports. Accordingly, the mined material removal means, e.g., the conveyor apparatus, must be capable of extension and retraction in conjunction with movement of the continuous miner.
Conveyor apparatus available commercially today can be viewed as severely limited with respect to its flexibility and ease of operation in providing the extension and retractability for following the continuous miner. A new apparatus and method are needed to provide removal of large amounts of mined material for continuous haulage conveyance out of the mine.
INTRODUCTION TO THE INVENTION
In the mining of coal today, mining companies are finding the need to provide for the removal of larger and larger volumes and weights of mined material by continuous haulage conveyance out of the mine. Conveyor apparatus and method are needed to receive and convey heavier loads, and to operate in the mine environment which typically subjects the conveyor apparatus to harsh and hostile chemical attack with small particles together with damaging physical forces placed on the conveyor structure by the larger volumes and weights of coal to be conveyed.
In the mining of coal, particularly but not limited to coal strip mines, many coal seams are exposed and/or identified which have a low vertical seam height. By low vertical seam height is meant less than standing room. The low coal seam vertical height makes it extremely difficult to impossible to recover the coal by conventional deep mining equipment and techniques. The low coal is left behind when the cover over the seam is too high to mine the coal by strip mining techniques. Moreover, since the vertical height of these coal seams is so low, it is extremely difficult, if not impossible, to mine the low coal with people in the shaft.
One technique which has developed to mine low coal is with the use of continuous mining equipment. A continuous miner works at the face of the low seam vertical height coal and separates the coal from the face of the mine. The coal produced from the continuous miner is passed preferably to a “continuous haulage” system for removal from the mine face, typically by passing through an extensible conveyor to a mainline conveyor for removal from the mine. By continuous haulage is meant the continuous transportation of the material mined from a continuous miner, from other mining machines, or from a production area to a main conveyor belt or belts leading to the surface or to a main terminal area where the mined material is processed.
Coal produced from the mine face in larger vertical height mines also is conveyed today by a continuous haulage system for removal from the mine.
U.S. Pat. No. 2,850,146, issued to Madeira, (hereinafter “Madeira”) discloses a structure and technique considered to be the beginnings of low belt structure as it is known today. U.S. Pat. No. 2,850,146 discloses a portable conveyor for use in a coal mine represented to be simple in the setting up thereof, and also by ready portability in the mine or the like. An endless conveyor is provided having a pair of cables suspended as catenaries on spaced roof jacks. The endless conveyor belt is represented to be readily and easily disassembled and moved from one location to another location where the conveyor is easily reassembled. When positioned at the new location, it is extensible and retractable with a minimum amount of effort.
U.S. Pat. No. 2,850,146 discloses structure which is cable mounted, supported by roof jacks. A drawback of the cable-mounted system involves problems attributable to failure of suspension of the conveyor line when even just one roof jack loses its support. Loss of roof support is a problem which can and does occur, resulting in the cable structure losing its support.
The U.S. Pat. No. 2,850,146 patent utilizes rollers, not sliders, and the structure disclosed in U.S. Pat. No. 2,850,146 is intended to be readily installed, but the actual structure design is deficient in the length of time actually needed to install it. The apparatus and methods disclosed in U.S. Pat. No. 2,850,146 are not designed to run continuous haulage because the Madeira conveyor does not form a track needed for the mobile bridge units extending from and attached to the continuous mining machine to tram or travel in order to form the continuous haulage system.
In underground mining, and particularly in but not limited to underground mining wherein the vertical work space affords less than standing room, physical tasks are made more difficult by the confined spaces and constraints imposed by the underground mine. Although the apparatus and method of the present invention are not intended to be limited by particular dimensions in a mine, physical movements and activity are made significantly more demanding in low seam mining, e.g., less than 48 inches in vertical height.
When conveyor apparatus is used in continuous haulage today to remove material from the mine, and when the conveyor apparatus is called upon to extend and retract in conjunction with the continuous miner, the conveyor must be repeatedly constructed and later broken down in the confining spaces and constraints within the mine. Conventional conveyor apparatus can be viewed as severely lacking in the areas of facilitating extension or retraction while accommodating the difficult physical activities found in the confining spaces or constraints in the underground mine. Novel apparatus and method are needed to facilitate rapid and flexible extension and retraction of the conveyor in the underground mine.
Conventional conveyor belts typically use idler rollers and/or roller bearings for carrying the main belt for hauling material on the endless conveyor belt. The idler rollers and/or roller bearings have difficult duty in the hostile environment of the mine. This hostile environment is attributable to water, corrosion, dust, or other hostile agents found in the mine. When the idler rollers or roller bearings need to be replaced, the load bearing surface typically undergoes a grinding operation by the belt as it passes. When the idler roller or roller bearing is ground to a sharp surface, the conveyor must be taken down to replace the belt.
The difficult duty of idler rollers or rollers containing roller bearings is made more acute with low vertical height mining because the rollers must be made of smaller diameter. The smaller diameter rollers must travel faster because of the higher number of revolutions per unit time. Accordingly, novel conveyor apparatus and method are needed to eliminate problems attributable to conventional idler rollers and other rollers using roller bearings.
It has been proposed to use slides as substitute apparatus for idler rollers. Slides are available commercially, made typically of stainless steel. However, stainless steel has a high coefficient of friction, e.g., such as on the order of 0.550-0.7, and the stainless steel wears o
Polka Alan R.
Szalankiewicz James J.
Walter Scott A.
Glantz Douglas G.
S&S Slides, Inc.
Valenza Joseph E.
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