US3542432A - Method for mining material from the entire face - Google Patents

Description

United States Patent inventors Appl. No. Filed Patented Assignee METHOD FOR MINING MATERIAL FROM THE ENTIRE FACE 6 Claims, 16 Drawing Figs.

US. Cl 299/18 Int. Cl E2lc 27/24 Field ofSearch 299/10, 11, 18, 64, 75, 76

References Cited UNITED STATES PATENTS 2/1903 Pawe] 299/75X Primary Examiner-Ernest R. Purser Attorney-David Young ABSTRACT: A method of mining material from the entire mine face with a rotary mining head that has hemiovate ends. The rotary mining head is advanced into the mine face for a major part of the head, and traversed through the material of the mine face to cut and break the material out of the mine face. This leaves cusps of material behind the rotary mining head. The mining head is retreated to the cusps of material, which are removed by traversing the rotary mining head through the cusps of material. This iast traversing movement positions the rotary mining head for the next advance into the mine face and the next mining operation.

Patented Nov. 24, 1970 /N\/EN7'O/?S; WILLIAM EM CRACKEN, FAY E MUNGER' BY MLW ATTORNEY Patented Nov. 24, 1970 Sheet HTTORNEY Patented Nov. 24, 1970 3,542,432

WILCIAM EM CRACKEN, FAY EMUNGER ATTORNEY Patented Nov. 24, 1970 3,542,432

l v ||ly \v" 7 v v I 'Fi. 83 32 Bi 10 INVh'N'IUR-i; WILLIAM E.M CRAQKEN, FSY EM GER BY ATTORNEY Patented Nov. 24, 1970 3,542,432

METHOD FOR MINING MATERIAL FROM THE ENTIRE FACE The instant invention relates to a method ofmining for mining material from the entire area ofthe mine face ahead of the mining machine.

In typical underground mining operations the material is mined from the mine face by a cutting and breaking action. The mining machine advances forwardly in the direction of the mine face to penetrate the face for the cutting and breaking action. It is a fundamentalobjective to mine the material at the highest rate, which is reflected in the rate of advance of the mining machine. The higher is the rate that the material is removed from the mine face, the higher is the rate of advance ofthe mining machine.

The mining machine customarily has a mining head at its forward end, which is sumped into the mine face and mines the material by cutting and breaking. After the mining head is operated over the entire face area, the mining machine is advanced to again sump the mining head into the mine face and the operation is repeated. lt is desired that the successive steps of advance be performed on a continuing basis, and the rate at which the material is mined from the mine face determines the rate at which the mining machine can be advanced for the successive steps ofmining the material.

Another factor that affects the rate of advance ofthe mining machine is that of roof control. It is a serious problem in underground mining operations that as the mine face is advanced there is produced an exposed roof which was formerly supported by the material that has been mined from under the roof. This gives rise to the possibility of roof falls. Due to the nature of the geological strata, roof falls may involve tons of material. such as slate and rock, with the potential to cause personal injury and damage to the equipment. Therefore, great care is taken in underground mining operations to control the roof, with the purpose practical, avoid falls, and this is even subject to government regulations having the force of law.

In mining operations the roof may be controlled by the use of posts or props set between the floor and the roof as a substitute for the mined material, to provide vertical support. Another form of roof control is timbering in which timbers are set vertically, usually at the opposite ribs, and another timber is laid across the top of the upright timbers immediately below and bearing up against the roof. Wedges are driven in to force the cross timber against the roof in close contact to provide vertical support. Still another form of roof control is by roof bolting in which bolts with long shanks, of the order of 3 feet to 4 feet in length, are driven in above the roof and a plate is laid against the roof and held in place by a nut that is turned on the bolt. Roof bolting is advantageous because it permits greater flexibility in the placement of the roof supports than is the case with timbers, the roof bolts have considerably less bulk than the timbers, and therefore are easier to handle and do not occupy as much space as the timbers. The principle of roof bolting is to tie the strata immediately above the roof to more secure strata, thereby supporting the lower strata from higher firmer strata.

Any of the roof control systems are nonproductive in nature, in that they do not directly produce mined material. The

roof control procedures interrupt the actual mining operation, since the mining machine is stopped to permit roof supports to be installed. It is a limiting factor that the mining machine may not advance beyond a given distance under unsupported roof. Therefore, when the mining machine is advanced through this distance it must be stopped until roof supports are installed. Then the mining machine may resume its advance through the given distance, at which time there is another shutdown while the roof supports are placed. The distance that a mining machine may advance under an unsupported roof is usually relatively short, so that the production of the machine is materially affected by the necessary interruptions to install roof supports, and it is not possible to realize the full production capacity of the machine.

g The mine face presents a face area which is bounded by the floor at the bottom, the roof at the top, and the ribs at the opposite sides, from which the material is :mined. it is desired to remove the greatest volume of material from the mine face. Consonant with this objective the corners of the mine face would be cut square, to mine all the material between the boundaries of the floor, roof and opposite ribs. However, the square cut corners at the roof produce a poor condition from the standpoint of roof control. The roof control is improved in the case of boring machines which have large circular boring heads that advance into the mine face in the direction of the axes of the circular boring heads. The boring heads produce an arcuate configuration ofthe roof at each rib, which is a portion of the circle of the boring head. The physical effect of such arcuate configuration of the roof at each rib is similar to that in an arch'in which the arch is self-supporting. However, the roof that is produced by the boring machines is not totally self-supporting, but there is a large measure of additional support for the roof stemming from the arched or curved configuration at the ribs. With this added measure of roofsupport it is possible to advance the mining machine through greater distances than would otherwise be the case before the machine is stopped for the installation of roof supports. This permits uninterrupted operation ofthe mining machine during longer periods of time, and materially improves the efficiency of the mining operation.

The boring type mining machine characteristically has a mining head which covers with entire face area. The mining head includes the circular boring heads and trimming cutting chains or trimming cutting bars which span the distance between the circular boring heads where the latter do not overlap. These trimming cutting chains or cutter bars provide a flat floor surface for the advance of the mining machine.

In another type of mining machine there is a rotary mining head which is considerably smaller than the area of the mine face from which the material is mined. The mode of operation is to sump the mining head into the material of the mine face, and then to traverse the mining head through the material to cut and break the material out of the mine face, and then to traverse the mining head through the material to cut and break the material out of the mine face, and this manner to cover the entire area of the mine face between the roof, floor and the opposite ribs. Such a mining machine is illustrated in the patent to James Kilbourne, US. Pat. No. 3,305,273,

Feb. 21, l967, for Mining Apparatus Supporting and Driving Construction. The rotary mining head of the patent has a plurality ofcutting bits disposed in a cylindrical form, which in the course of operating the mining machine produce square corners at the junctions of the roof with the opposite ribs. While this form of cutting head is effective to remove the greatest volume of material from the entire face area, it is not most satisfactory for roof control. This condition is improved by a rotary cutting head which has its opposite ends with a hemiovate form to form the roof with a curved or arched portion at each rib.

In mining the material it is desired to advance the rotary mining head into the mine face to the greatest depth that is practical, so that in the course of traversing the mining head through the mine face the cutting depth will be great, thereby cutting and breakinga greater volume of material out of the mine face during the traverse. The mining head that is formed with the hemiovate ends any be advanced into the mine face for a major part of the diameter of the head, but this leaves a substantial sized cusp of material on each rib during the traverse of the mining head. Such cusps on the ribs reduced the lateral clearance between the ribs, and. therefore, are undesirable. The improved method of mining the material with the rotary mining head provides a sequence of steps for mining the material that includes the removal of the cusps from the ribs, so as to provide the full width of lateral clearance between the ribs for movement of the mining machine.

Accordingly, it is an object of this invention to provide an improved method of mining material, in which the rotary mining head may be advanced into the mine face for a major part of its diameter, in order to increase the rate of removal of material during the traverse of the mining head through the material.

It is also an object of the invention to provide an improved 7 method of mining material with a rotary mining head in which the mining head is advanced into the material and cuts and breaks out the material during a traversing movement of the mining head, and removes thecusps ofa material from the ribs by another traversing movement of the mining head.

It is still another object of the invention to provide an improved method ofmining material with a rotary mining head that has hemiovate ends, in which a major part of the rotary mining head is advanced into the material and traversed through the material to cut and break out the material, during which cusps of material are left on the opposite ribs, and such cusps are removed from the ribs by another traversing movement ofthe mining head at a retreated position.

It is a further object ofthe invention toprovide an improved method of mining material with a rotary mining head in which .a cusp of material on the floor may be removed.

Other objects of the invention will appear hereinafter, the novel features and combinations being set forth in the appended claims.

In the drawings:

FIG. 1 is a side elevation of a mining machine in accordance with the invention;

FIG. 2 is a plan view ofthe mining machine;

FIG. 3 is a front elevation view of the rotary mining head with an outline of the mine face area in which the material is mined; I

FIG. 4 is an end elevation view of the rotary mining head;

' FIGS. 5 and 6 are elevation and plan views, respectively, showing the position of the rotary mining head at the mine face; I

FIGS. 7 and 8 are elevation and plane view, respectively, showing the position of the rotary mining head advanced into the mine face;

FIGS. 9 and 10 are elevation and plan views respectively, showing the rotary mining head at the end of its traversing movement;

FIGS. 11 and 12 are elevation and plan views, respectively, showing the retreated position of the rotary mining head after removing the floor cusp;

FIGS. 13 and 14 are elevation and plan views, respectively, showing the retreated position of the rotary mining head prior to removal of the rib cusps; and

FIGS. 15 and 16 are elevation and plan views, respectively, showing the position of the rotary mining head after removal of the rib cusps and prior to the next advance into the mine face.

Referring to the drawings, there is illustrated in FIGS. 1 and 2 a mining machine 10 in accordance with the invention, supported on endless traction treads 11,12 at opposite sides by which the machine in propelled. At the forward end of the mining machine 10 there is a rotary mining head 13, on a transverse axis, to be advanced or sumped into the mine face 14, and traversed through the material of the mine face, to mine material from the entire face area by a cutting and breaking action. The mining head 13 is supported on the forward end of a boom 15 by which it may be raised to the roof l6, sumped into the material of the mine face 14, and traversed through the material downwardly to the floor 16. The mining head 13 extends transversely between the opposite ribs 18,19 and the latter define the side boundaries of the face area that is mined by the mining head 13,

The boom 15 is connected to the mining machine main frame 20 on transverse pivots 21,22 on which the boom 15 is swung upwardly and downwardly by cylinders 23,24 connected between the mainframe 20 and the boom 15.

The mining machine 10 is powered by motors 25,26 on opposite sides ofthe boom 15. Driving connections 27,28 extend forwardly from motors 25,26, respectively, to transmissions 29,30, at opposite sides of the boom 15, from which the mining head 13 is driven. US. Pat. No. 3,305,273 illustrates in detail a form of the driving connections and transmissions by which the mining head 13 may be driven, in which the power of both motors 25,26 is delivered to the entire mining head 13,

The motors 25; 26 also provide power for driving traction threads 11,12. Drive connections 31,33 extend rearwardly from motors 25, 26, respectively to transmissions 33,34 at 0pposite sides ofthe main frame 20 for delivering the drive to the traction treads 11,12.

In the mining operation the material cut and broken out of the mine face 14 falls to the floor 17. There is a gathering head at the front of the mining machine 10. below the boom 15, The gathering head 35 has an apron or deck 36 with its leading edge at the floor 17. Gathering arms 37,38 at opposite sides of the gathering head 35 operate with an oscillating motion to reach down and to sweep the material into a conveyor 39 which extends longitudinally through the mining machine 10 from the gathering head 35 to the discharge boom 40 at the rear end of the mining machine 10. The conveyor 39 moves the mined material from the forward end of mining machine 10 to its rear end at which it is discharged to conveying apparatus for removing the mined material from the mining place. The gathering arms 37,38 are powered by the motors 25,26. Driving connections 41,42 extend forwardly from transmissions 33,34 respectively to gathering head transmissions 43,44, from which the gathering arms 37, 38 are driven.

In FIG. 3 there is a front elevation view of the rotary mining head 13. There is an intermediate section of the mining head 13 with spiral flights 51,52 at diametrically opposite positions, and additional spiral flights 53,54. Several cutting bit holders 55,55 are secured at spaced positions on the peripheries of the spiral flights 5152,5354. A cutting bit 56 is releasably secured in each holder 55. The cutting bits 56 and their holders 55 are disposed at spaced positions in the circumferential direction and in the axial direction of the mining head 13, such that when the mining head 13 rotates, the cutting bits 56, 56 sequentially engage the material of the mine face at several positions across the mine face.

At the left side of the intermediate section 50 of the mining head 13, as viewed in FIG. 3, there is a cutting chain 58 extending around a gear case 57 at the forward end of the boom 15, that may be constructed in the manner of US. Pat. No. 3,305,273. The path of cutting chain 58 is coincident with a major part of the circumference of the mining head 13, as best seen in FIG. 4. The chain 58 has a plurality of links 59,59 with connecting links 60,60, and articulated connections including pins 61,61. The pins 61, 61 project from the opposite sides of the chain 58 to be engaged by a sprocket 62 on the intermediate mining head section 50 at one side of the chain 58, and another sprocket 63 at the other side of the cutting chain 58, which is secured to the outer mining head section 65. The sprockets 62,63 rotate with the mining head 13 and by engagement with the outer ends of pins 61,61 of the cutting chain 58 drive the latter concurrently with the rotation of the mining head 13, which may be generally in the same manner as in US. Pat. No. 3,305,273.

A plurality of cutting bit holders 55 are secured to the links 59,60 of cutting chain58 at spaced positions along and across the latter to provide a pattern of cutting bits 56,56 in which they sequentially engage the material of the mine face 14 at spaced positions across the face, as the cutting chain 58 is moved by rotation ofthe mining head 13.

The mining head 13 has an outer mining head section 65 at the left side, as viewed in FIG. 3, outboard ofthe cutting chain 58. Spiral flights 66,67 are wound on one part of the mining head section 65 atdiametrically opposite positions, and spiral flights 68,69 are wound on another part of the mining head section 65 as continuations of the spiral flights 66,67 respectively. A plurality of cutting bit holders 55 with their cutting bits 56, are secured to the outer mining head section 65 on the spiral flights 66,67,68,69 69 at circumferentially and axially spaced positions to sequentially engage the material of the mine face 14 at spaced position across the latter during rotation of the mining head 13.

Beyond the outer mining head section 65 there is an end mining head section 70 as an axial extension of section 65. End section 70 is connected to section 65 by a telescoping cylinder part 71 that may be extended and retracted relatively to section 65. The inner portion of the end section 70 in the area of telescoping cylinder part 71 has spiral flights 72,73 wound at diametrically opposite positions as continuations of spiral flights 68,69 respectively, when end section 70 is extended, as illustrated in FIG. 3. Several cutting bit holders 55 and their bits 56 are secured at spaced positions on spiral flights 72,73 to sequentially engage the material of the mine face 14 at spaced positions across the latter. Beyond the spiral flights 72,73, there is a collar 74 and an end cap 75 which are of successively lesser diameters towards the outer end of the end section 70. A plurality of cutting bit holders 55 and their bits 56 are secured to the collar 74 and to the end cap 75 at spaced positions in the circumferential and axial directions to sequentially engage the material ofthe mine face 14 at spaced positions across the latter. The disposition of the cutting bits 56 is best seen in FIGS. 3 and 4.

At the right side of the intermediate mining head section 50 there is another cutting chain 58 like the cutting chain 58, but oppositely disposed, and such cutting chain 58' and its parts are identified by the same reference numerals, with the addition of a prime The right side of the mining head 13, as seen in FIG. 3, is the same as the left side, but the elements are oppositely disposed. The elements of the right side of the mining head 13 are identified by the same reference numerals as applied to the elements at the left side with the addition of a prime to each reference numeral, and the description of the left side of the mining head 13 applies also to the right side ofthe mining head. i

The cutting bits 56,56 on the intermediate mining head section 50 and on the outer mining head sections 65,65 are all at the same radius, and in rotating the mining head 13 these cutting bits 56,56 move in the form of a cylinder. Likewise, the cutting bits 56,56 on the cutting chains 58,58'58 are disposed at the same radius so that they also move in the same cylindrical form in the portion of their paths which coincide with the mining head These cutting bits 56,56 moving in the cylindrical form, develop a flat intermediate surface 78 on the roof 16 and a flat intermediate surface 79 on the floor 17. Beyond the outer mining head sections 65, 65', the cutting bits 56,56 which are on the end mining head sections 70,70, are at positions of decreasing radial distances towards the outer end of the mining head 13. In the rotation of the mining head 13, the cutting bits 56,56 on the end mining head sections 70,70 move in a hemiovate form and produce curved or arched surfaces 80,81 on the roof 16 downwardly to the rib 18. Similarly, the floor 17 is formed with a curved surface 82 up to the rib 18 and curved surface 83 up to the rib 19. However, the flat intermediate surface 79 on the floor 17 is of sufficient width to accommodate the opposite traction treads 11,12 as seen in FIG. 3, for movement ofthe mining machine on a flat part ofthe Hour 17.

In FIG. 3 the total cutting profile ofthe mining head 13 is illustrated by the phantom perimetal line 85. The profile line 85 illustrates the equal radial distances ofthe cutting bits 56,56 of the intermediate mining'head section 50, of the outer mining head sections 65,65, and of the cutting chains 58,58, and the decreasing radial distances of the cutting bits 56,56 on the end mining head sections 70,70which form the hemiovate end sections of the mining head 13. At each extreme end of the mining head 13, the cutting bits 56, 56 are in a crown disposition, as best seen in FIGS. 3 and 4, and provide flattened ends of the opposite hemiovate sections of the mining head 13, to cut the ribs 18,19.

As illustrated herein, and particularly with reference to FIGS. 1 and 4, the mining head 13 is rotated in the clockwise direction so that the cutting bits 56,56 engage the material in the mine face 14 in a descending direction. As viewed in FIG.

3, the cutting bits 56,56 move downwardly from top to bottom of the profile line 85. The removal of the material from the mine face 14 is a cutting and breaking action in which the cutting bits 56,56 cut into the material, and concurrently, the cutting bits along with the several spiral flights break the material out ofthe mine face and it falls to the floor 17.

Referring to FIGS. 5 and 6, the rotary mining head 13 is positioned at the top ofthe mine face 14 by swinging the boom 15 upwardly to the roof 16. The first step in the mining method is to advance the rotary mining head 13 into the mine face 14, which is the sumping movement of the mining head 13. This is illustrated in FIGS. 7 and 8 wherein it is seen that the rotary mining head 13 has been moved along the roof 16 into the material of the mine face 14. This exposes a new portion of the roof 16 along a line or level that is a continuation of the roof 16 that has been previously exposed. The mining head 13 rotates as it is advanced into the mine face 14 so that the material is cut andbroken out of the mine face 14 during such advance. This material falls to the floor 17 where it is collected by the gathering arms 37,38.

The depth of advance of the rotary mining head 13 into the mine face 14 determines the volume of material that is removed during traversing movement of the mining head 13. Therefore, it is desired to. advance the mining head 13 to the greatest depth practicable, in order to increase the rate of mining removal of material. As illustrated in FIG. 7, the rotary mining head 13 may have a diameter of 36 inches (36" and a major part of the mining head 13 is advanced into the mine face, which may be an advance of 30 inches (30"). As seen in FIG. 8, the hemiovate ends of the mining head 13 do not completely overlap or engage the material ofthe mine face 14. When the mining head 13 is traversed through the material of the mine face 14 downwardly towards the floor 17, as illustrated in FIG. 9 and 10, cusps of material 90,91 are left on the ribs 18,19 respectively, behind the mining head 13. By reason ofthe circular form of the mining head. 13, there is also a cusp ofmaterial 92 which remains on the floor.

The rotary mining head 13 is then retreated along the floor 17 to the position illustrated in FIGS. 11 and 12, which removes the cusp of material 92 from the floor 17. The rotary mining head 13 is then moved to the position illustrated in FIGS. 13 and 14, in which the axis of the mining head 13 is alined with the center lines of the cusps of material 90,91 on the ribs 18,19 respectively. This is another retreated position of the mining head 13, so termed because the mining head 13 is disposed rearwardly away from the newly exposed mine face 14.

The rib cusps of material 90,91 are removed by traversing the rotary mining head 13 upwardly to the roof 16 by swinging the boom 15 upwardly. The crown ends of the rotary mining head 13 are of substantially the same width as the base width of the rib cusps of material 90,91, so that the crown ends of the mining head 13 meet the cusps 90,91 and remove the latter during the upward traverse of the mining head 13. This then places the mining head 13 at the roof 16, as seen in FIGS. 15 and 16. The mining head 13 may then be advanced along the line of the roof 16 to sump the mining head 13 into the mine face 14, in the manner illustrated in FIGS. '7 and 8, for the next sequence of the steps of the method of mining, as has been described above.

The method ofmining provides a sequence of steps with the rotary cutting head 13, by which the several movements of the mining head 13 occur in sequence to cut and break the material out of the mine face .14, followed by the removal ofthe floor cusp of material 92, and the rib cusps of material 90,91, and positioning the mining head 13 at the roof 16 for the next step of advancing the mining head 13 into the mine face 14 for the next sequence of steps. As illustrated herein, the mine face 14, the roof 16, the floor 17, and the ribs 18,19 are shown as nice regular and clean surfaces. However, it will be understood that the illustrations are representations of the respective surfaces, and in practice it occurs that the exposed surfaces in the mine are rough since the material is cut and broken out of the mine.

Thus, for example, after the removal of the rib cusps, the rib surfaces are clean by mining standards, but there may still remain some roughness or irregularity of material on the ribs 18,19 due to the nature ofthe mining operation and the fact of working with geological strata. Also, it may be unnecessary to remove the floor cusp 92 with the rotary mining head 13, as described above, since it sometimes occurs that the material at the floor 17 is not bound very firmly in place, and such material may break loose simply by the bulldozing action ofthe front edge of the gathering head deck 36.

We claim:

1. A method of mining material from a mine face with a transverse rotary mining head that has a hemiovate form at each end of the mining head, said mine face being bounded by a roof at the top, a floor at the bottom, and by a rib at each side. comprising the steps of advancing a major part ofsaid rotary mining head into the material of the mine face, traversing said rotary mining head through the material of the mine face between said roof and said floor and leaving cusps of material on said rib behind the mining head along the path of the traverse, rotating said rotary mining head and cutting and breaking material out of the mine face as the rotary mining head is advanced into the mine face and as the rotary mining head is traversed through the material of the mine face between said roof and said floor, retreating said rotary mining head to said cusps of material on said rib, and traversing said rotary mining head between said floor and said roof and along said cusps on said rib to remove the material of the cusps from said rib.

2. A method of mining material from a mine face as recited in claim 1, said cusp of material remains on each rib as the totary mining head is traversed through the material ofthe mine face. and traversing said rotary mining head through said cusp of material on each rib upwardly from the floor towards the roof.

3. A method of mining material from a mine face as recited in claim 1, retreating said rotary mining head to the position of said cusps of material, and traversing said rotary mining head through the cusps ofmaterial from the floor towards said roof.

4. A method of mining material from a mine face with a transverse rotary mining head that has a hemiovate form at each end ofthe mining head, said mine face being bounded by a roof at the top, a floor at the bottom, and by a rib at each side, comprising the steps of advancing a major part of said rotary mining head into-the material ofthe mine face at the roof, traversing said rotary mining head through the material of the mine face down to the floor and leaving cusps of material on the ribs behind the mining head along the path of traverse from the roof down to the floor, rotating said rotary mining head and cutting and breaking material out of the mine face as the rotary mining head is advanced into the mine face and as the rotary mining head is traversed through the material of the mine face from the roof down to the floor, retreating said rotary mining head to said cusps of material on the ribs, and traversing said rotary mining head up to the roof and along said cusps of material on the ribs to remove the material of the cusps.

5. A method of mining material from a mine face as recited in claim 4, retreating said rotary mining head along the floor to said cusps of material on the ribs, and traversing said rotary mining head from the floor to the roof along said cusps of material to remove the material ofthe cusps.

6. A method of mining material from a mine face as recited in claim 4, traversing said rotary mining head upwardly to the roof along said cusps of material to remove the material of the cusps, and placing said rotary mining head at the roof in position to be advanced along the roof and into the material of the mine face.

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