US3301599A - Method of continuous open-pit mining and apparatus therefor - Google Patents

Description

Jan. 31, 1967 J, w. HEIMASTER 3,301,599

METHOD OF CONTINUOUS OPEN-PIT MINING AND APPARATUS THEREFOR 4 Sheets-Sheet 1 Filed Feb. 2'7, 1964 INVENTOR JOHN W. HEIMASTER BY KM A TTORNEY Jan. 31, 1967 J. w. HEIMASTER 3,391,599

' METHOD OF CONTINUOUS OPEN-PIT MINING AND APPARATUS THEREFOR 4 Sheets-Sheet 2 Filed Feb. 27, 1964 WENEHEH NILE;

WIRE.

W O N w E i TER J H .H IM 5; BY

A TTORNE V Jan. 31, 1967 J. w. HEIMASTER 3,3915% METHOD OF CONTINUOUS OPEN-PIT MINING AND APPARATUS THEREFOR Filed Feb. 27, 1964 4 Sheets-Sheet 5 1 INVENTOR.

JOHN W.HElMASTER ATTORNEY Jan. 31, 1967 J. w. HEIMASTER 3,301,599

METHOD OF commuous OPEN-PIT MINING AND APPARATUS THEREFOR Filed Feb. 27, 1964 4 Sheets-Sheet 4 ENTOR JOHN W.HE|MASTE ATTORNEY United States Patent METHOD OF CONTINUOUS OPEN-PIT MINING AND APPARATUS THEREFOR John W. Heimaster, Charleston, W. Va., assignor to Union Carbide Corporation, a corporation of Ne York Filed Feb. 27, 1964, Ser. No. 347,753

7 Claims. (Cl. 29918) This invention relates to a novel method for open-pit mining. More particularly, this invention relates to a method for open-pit mining wherein the strata containing potentially valuable minerals are removed in a substantially continuous manner. In a still more particular aspect this invention relates to a method for substantially continuously mining coal in an open pit mine.

In many areas of the world coal seams are found fairly near the surface, so that the overburden can be stripped and the uncovered seam mined. In the past, mining of these seams generally has been effected by dynamiting the seam and loading the resulting coal fragments with a shovel onto a truck for transportation from. the mine site. This technique is not particularly desirable, however, because, in addition to the dangers inherent in the use of explosives, it is not a particularly economical method due to its cyclic nature which requires idle crews and machinery during the blasting operation and the like.

It has been found by this invention that coal and other seams of this type can be easily, safely and economically mined by continuous mining systems of the type heretofore employed in underground mines. These continuous mining systems generally comprise, in combination, a mechanical means for disintegrating and dislodging the strata material from the seam and a means for substantially continuously and simultaneously transporting the disintegrated strata material from the locus of the disintegration means to a substantially separate place, such as a continuous miner in combination with a conveyor system extending out of the mine.

The area to be mined is prepared by any convenient technique, i.e., the overburden is removed from the seam to be mined with shovels, bulldozers, draglines, wheel excavators and the like. After the removal of the overburden the seam is mine-d in accordance with the method of this invention.

The mining technique of this invention generally comprises the removal of the selected strata from a plurality of substantially linear, parallel and contiguous troughs or courses of substantially the same height and width. Each course being mined has a floor, at least one side wall and an end formed from the surrounding, in-place strata material, but has no ceiling. In a preferred embodiment of this invention the course being mined is laterally displaced from any drop-off by a distance sufficient to provide subadjacent support to the course being mined.

- Each course is formed by the mechanical disintegration and dislodging of the selected strata material, for example coal, 'from a "wall which is transverse the direction of generation of the course; i.e., an end of the course. The disintegration and dislodging is accomplished by the use of apparatus such as the continuous miners of the type heretofore employed in bore mining, such as rippers, borers and the like. Continuous miners of this type are disclosed in US. Patent No. 1,603,621 to McKinlay; U.S. Patent No. 2,695,164 to Arentzen;'U.S. Patent No. 2,788,- 200 to Barret-t; U.S. Patent No. 2,699,328 and U.S. Patent No. 2,826,402 to Alspaugh et al.; U.S. Patent No. 2,719,709 to Salmons; U.S. Patent No. 2,734,731 to Cartlid-ge et al.; and U.S. Patent No. 2,776,125 to Robbins et al. These continuous miners generally comprise a selfpropelled vehicle having mounted on one end thereof means for mechanically disintegrating and dislodging the selected strata and means for removing the dislodged strata fromthe immediate area being mined. It is preferred that the continuous miners be employed in combination with a train of conveyors, such as those described in U.S. Patent 2,722,409 to Bergmann, U.S. Patent 2,780,451 to Alspaugh et al. and U.S. Patent 2,948,552 to Moon. When such a train is employed it is preferred that each conveyor be self-propelled so that the miner is not required to tow the conveyor train.

The mining method of this invention is illustrated in the accompanying drawings in which:

FIGURE 1 is a fragmentary plan view of a coal mine in which the method of this invention is being carried out;

FIGURE 2 is a fragmentary elevation view, partly in section, taken along line 22 in FIGURE 1, of a coal mine being mined in accordance with this invention;

FIGURE 3 is a fragmentary cross-sectional view, taken along line 33 in FIGURE 1, of a coal mine being mined in accordance with this invention;

FIGURES 4 through 6 illustrate a preferred sequence of steps employed in the utilization of the mining method of this inveniton;

FIGURE 7 is a fragmentary elevation view, partly in section, of a mining machine adapted for use in the mining method of this invention;

FIGURE 8 is a cross-sectional view, taken along line 88 in FIGURE 7, of a mining machine adapted for use in the mining method of this invent-ion;

FIGURE 9 is a rear schematic view of a mining machine adapted to cut a groove in the floor of the course being mined to aid in steering the conveyor train employed in combination with the mining machine;

FIGURE 10 is a cross-sectional fragmentary view taken along line 1010 in FIGURE 9;

FIGURE 11 is an elevation view, partly in section, of a suitable steering mechanism for the conveyor units employed in conducting the mining method of this invention; and

FIG. 12 is a plan view, partly in section along line 1212 in FIGURE 11, of the steering mechanism.

With reference mainly to FIGURES 1 through 3, the apparatus employed in carrying out the method of this invention comprises generally self-propelled continuous miner 1 equipped with disintegrating and dislodging means 3, means for collecting the disintegrated coal, not shown, and means 5 for transporting the disintegrated coal to the rear of mining machine 1. A train of self-propelled conveyors 7 is attached to the rear of mining machine 1 and extends behind mining machine 1 out of the course being mined and ultimately parallel to belt conveyor 9 and discharges the coal onto belt conveyor 9 for transportation away from the mine site.

In operation, continuous miner 1 is trammed across the surface of coal seam 11, from which the overburden has ben removed, to point 13 adjacent to unremoved overburden 15. The miner then mines a generally downwardly inclined ramp 17 until the depth of cut 1 9 approximates the height of disintegration and dislodging means 3 of miner 1, and then mines a substantially horizontal linear course A (FIGURES 4 and 5) for the full length of the exposed seam. The miner is then trammed back out of the course thus mined and to a position adjacent to said course and mines course B and then, in a similar manner, mines courses C and D. The miner is again trammed out of the pit and back to point 13, down ramp 17 and extends'ramp 17 until the depth of cut again approximates that of the height of disintegration and dislodging means 3 of miner 1, and mines course E. The pattern is then continued until the full depth of the seam is reached, for example, with course M in FIGURES 4 and 5, when the miner is riding on the underlying strata 21. In FIGURES 1 through 3, the miner is shown part way through course H. The sequence is continued until, with course a in FIG- URE 6, the full width of the exposed seam has been mined to a depth approximating the height of disintegration and dislodging means 3 of miner 1. The general mining sequence is continued until, with course m in FIGURE -6, the full width and height of exposed seam 11 has been mined.

The sequence outlined above and illustrated in FIG- URES 1 through 6 is not critical, and other sequences can be employed as desired. It is preferred, however, that the course being mined be separated laterally from dropoff 23 by a distance 25 sufficient to provide sufficient subadjacent support to the strata on which miner 1 rests to prevent its collapse clue to the weight of mining machine 1. The magnitude of distance 25 will vary depending upon the strength of the seam being mined as well as the width of the course. In general, however, this distance will be equal to at least one-half the width of a single course, and preferably one width of a single course, as is shown in the drawings.

Modifications of this technique can be readily employed if desired. For example, although the technique shown and described results in the production of high vertical side walls, it is clear that one can leave stepped walls if desired. Similarly, the ends of the various courses can be in substantially the same plane, leaving a vertical end extending the full height and width of the seam being mined or, in the alternative, the courses on the lower levels can be shorter than those immediately above, resulting in a stepped end. Moreover, the courses need not be arranged vertically, as shown in FIGURES 4 and 5, but can be staggered if desired.

The conveying system employed can be varied as desired. For example, instead of employing a train of conveyors as shown in the drawings and described above, one can employ a stationary conveyor system situated on a shelf above or below the shelf of the course being mined and a miner whose conveyor is adapted to discharge onto the stationary conveyor. Alternatively, one can direct the discharge from conveying means 5 to a point behind mining machine 1 or to an adjacent shelf above or below the course being mined and collect the disintegrated coal with a self-propelled coal loader of the type known to the art in combination with a conveyor train.

The continuous mining machines which are employed in the method of this invention fall into two general classes: (1) those whose disintegration and dislodging' means comprise a plurality of rotary front-face cutters, such as those disclosed in the patents to McKinlay, Salmons, Cartlidge et al., Robbins et al. and Alspaugh et a1.; and (2) those whose disintegration and dislodging means travel about an axis which is substantially parallel to the wall being mined, such as ripper miners and the like as disclosed in the patents to Barrett and Arentzen. Miners of the first class are gene-rally preferred for use in the method of this invention because of their ability to continuously generate a substantially vertical face perpendicular to the direction of travel, whereas the miners of the second class generate the face in a cyclic manner by sweeping vertically up and down the face and horizontally across the face.

Because all the continuous miners vigorously agitate the coal as it is disintegrated and dislodged, it is necessary to provide the miner with means for confining the dislodged coal to the proximity of the face being generated by the machine. This is readily accomplished by providing the mining machine with a shield extending from behind the disintegration and dislodging means forward to the face being generated in seam or, if desired, beyond the face and overlapping the face.

One suitable shield arrangement is shown schematically in FIGURES 7 and 8. The shielding comprises generally ver ical .rfi shield .27 .afiixed to mining machine 1 at a point behind disintegration means 3, shown in phantom, normally horizontal rotatable shield '29 and removable side shield 31. Rear shield 27 is of such configuration and projected area as to approximate the configuration and projected area of face 33 being gene-rated by disintegration and dislodging means 3 in seam 11. Normally horizontal shield 29 lies in a generally horizontal plane above the level of the top of disintegrating and dislodging means 3 and is of suificient width and depth to extend from rear shield 27 forwardly beyond face 33 and a suffi-cient distance to either side of disintegration and dislodging means 3 to overlap wall 35 in the course being mined and wall 37 of the adjacent course. Horizontal shield 29 is rotatably mounted on support arm 39 and mast 41 to rotate about axis 43, and is supported in a normally horizontal position by flexible cable or chain 45 running from the top of mast 41 to projection 47 in horizontal shield 29. Thu-s, shield 29 may rotate upwardly to clear the ground in the event mining machine 1 makes too deep a cut but is restrained from contacting disintegrating and dislodging means 3. Side shield 31 is removably mounted on rear shield 27 and is of sufiicient height to extend from about the surface of the seam on which mining machine 1 rides to above the plane of horizontal shield 29 a distance sufficient to provide a seal in the event shield 29 is rotated upwardly. Side shield 31 also extends from rear shield 27 forwardly beyond face 33 in seam 11 in a substantially parallel relationship to wall 37 of the adjacent course. Side shield 31 is rem-ovalbly mounted to permit the use of mining machine 1 in the generation of the first course of any level in the mine. The bottom edge of side shield 31 is bevelled at 49 to provide clearance in the event the cutter head of mining machine 1 is on a downward tilt with respect to the surrounding strata.

Various modifications of the shielding will readily occur to those skilled in the art. For example, side shield 31 may be removably attached to horizontal shield 29, instead of rear shield 27, the machine may be adapted to permit the use of side shields on either or both sides and the like.

To aid in controlling the conveyor train during the mining operation, particularly during t ramming, it is preferred that mining machine 1 be equipped with a cutter bar oriented to cut a. groove in the floor under the mining machine and that the wheels of each conveyor be steerable in response to the movement of a guide wheel riding in the groove.

A suitable arrangement for mounting the cutter bar is shown in FIGURES 9 and 10 and for the conveyor steering system is shown in FIGURES l1 and 12.

With reference to FIGURES 9 and 10, a conventional cutter bar 51 containing chain 53 and cutting elements 55, of sufiicient length to cut shallow groove 57 in the floor of scam 11 is mounted on arm 50 attached to the rear of machine 1. Chain 53 and cutting elements 55 are driven in the direction of arrow 61 by flange-mounted gear motor 63 which is also mounted on arm 59. Because most mining machines pivot about a point forward of the rear of machine 1, arm 59 is preferably mounted on slide 65 riding in guides 67 attached to the rear of machine 1. Arm 59 is urged sideways by single-acting hydraulic cylinders 69 and pistons 71 to maintain the cutter bar approximately on the center line of the course taken by machine 1 and to prevent the generation of too wide an arc in groove 57 on turning. Cutter bar 51 is raised and lowered by double-acting hydraulic cylinders each mounted on axle 81 secured to upstanding pivot 83 attached to the bottom of conveyor unit 85. For turning each axle 81 about pivot 83 lever arm 87 forms a bell crank with axle 81. The outer ends of lever arms 87 are connected by common link 89 which is pivotably connected at 91 to groove follower support member 93 horizontally rotatable about vertical pivot 95 under unit 85. Member 93 carries groove following means, such as spaced rollers 97 projecting downwardly into groove 59 in seam 11. Rollers 97 are equally spaced from pivot 95 a distance great enough to give the desired mechanical advantage for easy steering. Groove follower support member 93, when angularly displaced -by groove 57, swings connecting link 89 toward one wheel 79 or the other, causing both wheels to be turned in the desired direction. Tension spring 99 is connected between projection 101 depending from the bottom of unit 85 and the end of member 93 for normally urging the steering mechanism in a centralized position.

Convey-or unit 85 is connected to conveyor unit 103 by swivel tongue 105 projecting between bifurcated lug 107 into which coupling pin 109 is urged by compression spring 111 extending around pin 109.

What is claimed is:

1. Method for mining a selected geological strata material from which the overlying strata have been removed which comprises substantially continuously generating a generally downwardly inclined course from the surface of said strata material to a desired depth and thereafter substantially continuously generating a substantially horizontal course as an extension of said inclined course through said strata material, generating a second course contiguous to and substantially parallel with the first course and repeating the sequence until the width of the exposed strata material has been traversed, each course having a floor, at least one side, an end and no ceiling, each course being generated by substantially continuously disintegrating and dislodging the strata material from said end, and substantially continuously and simultaneously removing the dislodged strata material from the end of said course and transporting it to a substantially separate place.

2. Method for mining a selected geological strata material from which the overlying strata have been removed which comprises substantially continuously generating a generally downwardly inclined course from the surface of said strata material to a desired depth and thereafter substantially continuously generating a substantially horizontal course as an extension of said inclined course through said strata material, generating a second course contiguous to and substantially parallel with the first course and repeating the sequence until the width of the exposed strata material has been traversed, each course having a floor, at least one side, an end and no ceiling, each course being generated by substantially continuously disintegrating and dislodging the strata material from said end, confining the dislodged strata material to a zone adjacent to said end, and substantially continuously and simultaneously removing said dislodged strata material from said zone and transporting it to a separate place.

3. Method for mining a selected geological strata material from which the overlying strata have been removed which comprises substantially continuously generating a generally downwardly inclined course from the surface of said strata material to a desired depth and thereafter substantially continuously generating a substantially horizontal course as an extension of said inclined course through said strata material, generating a second course parallel to and contiguous with the first course and thereafter generating in a similar manner a sufiicient number of courses to traverse the exposed width and depth of said strata material, each course being generated having a floor, at least one side, an end and no ceiling and being laterally separated from a drop-off by a distance sufficient to provide subadjacent support to said course, each course being generated by substantially continuously disintegrating and dislodging the strata material from said end, and substantially continuously and simultaneously removing the dislodged strata material from the end of said course and transporting it to a substantially separate place.

4. Method for mining a selected geological strata material from which the overlying strata have been removed which comprises substantially continuously generating a generally downwardly inclined course from the surface of said strata material to a desired depth and thereafter substantially continuously generating a substantially horizontal course as an extension of said inclined course through said strata material, generating a second course parallel to and contiguous with the first course and thereafter generating in a similar manner a sufficient number of courses to traverse the exposed width and depth of said strata material, each course being generated having a floor, at least one side, an end and no ceiling and being laterally separated from a drop-off by a distance sufficient to provide subadjacent support to said course, each course being generated by substantially continuously disintegrating and dislodging the strata material from said end, confining the dislodged strata material to a zone adjacent to said end, and substantially continuously and simultaneously removing said dislodged strata material from said zone and transporting it to a separate place.

5. A continuous mining machine comprising in combination a self-propelled vehicle having mounted on one end thereof means for disintegrating and dislodging selected strata material from a solid seam of said material and means for confining the disintegrated and dislodged strata material to the proximity of the disintegration and dislodging means comprising (1) a generally vertical shield behind said disintegration and dislodging means having a projected area and configuration which approximates the projected area and configuration of the face generated by said disintegnation and dislodging means; (2) a normally horizontal shield located in a generally horizontal plane above said disintegration and dislodging means and extending from said vertical shield forward to and beyond the plane of the face generated by said disintegration and dislodging means and extended laterally a distance equal to at least the width of the face generated by said disintegration and dislodging means, said horizontal shield being rotatably mounted on an axis behind said dis-integration and dislodging means; and (3) at least one removable, substantially vertical side shield extending from said vertical shield forward to and beyond said face and from the level on which the machine rides upwardly at least to the plane of said horizontal shield.

6. The mining machine as claimed in claim 5 wherein said side shield is removably attached to said horizontal shield.

7. The mining machine as claimed in claim 5 wherein said side shield is removably attached to said vehicle and extends upwardly to a height which is greater than the normally horizontal plane of said horizontal shield.

References Cited by the Examiner UNITED STATES PATENTS 2,920,879 l/ 19-60 Driehaus 299-64 3,098,641 7/1963 Baldwin 299-18 X 3,169,797 2/1965 Lundquist 299-64 3,190,696 6/1965 Stalker 299-18 X ERNEST R. PURSER, Primary Examiner.

Claims (1)

1. METHOD FOR MINING A SELECTED GEOLOGICAL STRATA MATERIAL FROM WHICH THE OVERLYING STRATA HAVE BEEN REMOVED WHICH COMPRISES SUBSTANTIALLY CONTINUOUSLY GENERATING A GENERALLY DOWNWARDLY INCLINED COURSE FROM THE SURFACE OF SAID STRATA MATERIAL TO A DESIRED DEPTH AND THEREAFTER, SUBSTANTIALLY CONTINUOUSLY GENERATING A SUBSTANTIALLY HORIZONTAL COURSE AS AN EXTENSION OF SAID INCLINED COURSE THROUGH SAID STRATA MATERIAL, GENERATING A SECOND COURSE CONTIGUOUS TO AND SUBSTANTIALLY PARALLEL WITH THE FIRST COURSE AND REPEATING THE SEQUENCE UNTIL THE WIDTH OF THE EXPOSED STRATA MATERIAL HAS BEEN TRAVERSED, EACH COURSE HAVING A FLOOR, AT LEAST ONE SIDE, AN END AND NO CEILING, EACH COURSE BEING GENERATED BY SUBSTANTIALLY CONTINUOUSLY DISINTEGRATING AND DISLODGING THE STRATA MATERIAL FROM SAID END, AND SUBSTANTIALLY CONTINUOUSLY AND SIMULTANEOUSLY REMOVING THE DISLODGED STRATA MATERIAL FROM THE END OF SAID COURSE AND TRANSPORTING IT TO A SUBSTANTIALLY SEPARATE PLACE.

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