The present invention relates generally to mining and specifically to conveying in remote mining of bedded mineral deposits.
Known methods of remote mining in bedded mineral deposits such as coal seams employ a mining machine that excavates mine openings to some distance from the seam exposure on the surface and means of conveying are required to transport the excavated material to the surface. In most of the present systems, conveying machines consisting of multiple conveyors are advanced into the mine openings from the surface. For example, U.S. Pat. Nos. 5,112,111, 5,232,269 and 5,261,729 to Addington at al. disclose an assembly of conveyors and a mining machine advanced into the seam without interrupting the flow of aggregate material by separate means designed to pull at the forward end and push at the rearward end. Similarly, U.S. Pat. No. 5,609,397 to Marshall at al. discloses an assembly of conveyors interconnected with a mining machine and a driving device located outside the seam and consisting of rack and pinion or, alternately, reciprocating cylinders, linear tracks, linear or rotary drives, chains, cables or other mechanical devices. The U.S. Pat. No. 5,692,807 to Zimmerman discloses a guidance assembly for extending and retracting an assembly of conveyors in and out of the seam. The U.S. Pat. No. 3,497,055 to Oslakovic at al. discloses a multi-unit train of conveyors having a self-propelled unit at each end coupled to intermediate units, each end unit being capable of towing the intermediate units. The U.S. Pat. No. 2,826,402 to Alspaugh at al. discloses a train of wheeled conveyor sections pulled into the mine opening and pushed out of it by a self-propelled mining machine. Buckling of the train is avoided by the grooves made by the mining machine in the floor, said grooves spaced the same distance as the treads of the wheels carrying the conveyor sections.
At present, as the interconnected combination of the mining machine and a conveying assembly comprising a plurality of conveyors is advanced some distance into the seam from a launch vehicle located on the outside, the axial force within the combination becomes excessive with respect to its length and the combination becomes less rigid. As a consequence, it becomes difficult to steer the mining machine located at the front of the combination and the conveying assembly itself can become unstable, which limits the penetration depth of mining. Furthermore, pulling the conveying assembly at the rearward end when it becomes entrapped by a rock fall may sometimes cause the conveying assembly to brake. It would therefore be desirable to provide for advancing and withdrawing the conveying assembly while minimizing the axial force within the conveying assembly.
Where the conveying assembly consists of a plurality of conveyor units, each of the individual conveyors requires a separate input of electric power which, in turn, requires coupling and uncoupling of electrical cables as the assembly is advanced into or retracted from the mine opening. It would be therefore desirable to provide a power input that does not require electric power at each individual conveyor of the assembly.
If the electric power input is not provided at each individual conveyor, the conveying assembly cannot be extended without interruption, as claimed in the U.S. Pat. No. 5,112,111 to Addington at al. It would therefore be desirable to provide for extending the conveying assembly while minimizing the time required for such extension of the machine.
Where open conveyors are used, they are prone to damage by falls of rock from unsupported roof. Often, when rock falls occur, mining must be interrupted and the conveying assembly brought to the surface in order to remove fallen rock from the machine and to repair damage. It would therefore be desirable to provide a conveying assembly that is enclosed in a protective enclosure and that is capable of withstanding at least moderate rock falls.
Electric cables, control cables and hoses for the remote mining machine that lay atop the conveying assembly are also prone to damage by rock falls. It would therefore be desirable to provide protective enclosures for cables, hoses and other services provided for the remote mining machine.
A remote mining machine located at the forward end of the conveying assembly may become entrapped by fallen rock and the traction force of the conveying assembly may not be sufficient to extract the mining machine. It would therefore be desirable to provide independent means of extracting the mining machine from the seam.
One type of mining for which the present invention is intended to be used is highwall mining. With highwall mining, the mining machine penetrates a substantially vertical face containing a seam. The mining machine digs into the face substantially perpendicularly thereto. To ensure the structural integrity of the mine is maintained, pillars of unmined material are left between the holes dug by the mining machine. These pillars support the roof and are therefore essential to avoiding a rock fall. Those of ordinary skill in the art will understand that in order to maintain minimum acceptable pillar thickness, it is desirable to dig exactly perpendicularly to the face. Any angular deviation by the mining machine as it travels requires an increased initial pillar width, which decreases the amount of material that can be removed from the mine. Therefore it is desirable to maintain accurate and precise knowledge of where the mining machine is located. Likewise, it is desirable to navigate the mining machine precisely and accurately to a desired location. In this manner, the operator can ensure that the desired mining path is followed.
One known method of determining mining machine position employs a system of gyros and accelerometers to estimate the distance traveled by the mining machine. This type of known method uses complicated software that requires several minutes to initiate during which the mining machine cannot be moved. The method also requires periodic re-calibration during use, which also requires the mining machine be at rest. Furthermore, this system is expensive, costing more than $100,000. Thus, what is needed is a cost-efficient mining machine that can accurately and precisely determine the position of the mining machine head.
Accordingly, it is an object of the present invention to provide a method and apparatus for advancing a remote conveying assembly without causing excessive axial forces within the assembly, by providing tractive forces at multiple locations along the length of the assembly.
Another object of the present invention is to provide a method and apparatus for remote conveying that does not require electric power at each conveying section of the conveying assembly.
Another object of the present invention is to provide a method and apparatus for extending the conveying assembly that minimizes the time required for extensions.
Another object of the present invention is to provide a method and apparatus for protecting the remote conveying assembly, electric cables and other services from damage by rock falls.
Another object of the present invention is to provide a method and apparatus for advancing and steering the remote mining machine independently of advancing the conveying assembly.
Another object of the present invention is to provide a method and apparatus for accurately and precisely determining the position of the mining machine within the seam.
These and other objects of the present invention will become clear from the detailed description of the invention, the drawings, and the claims included below.
The present invention is described with reference to the accompanying drawings, in which like reference characters reference like elements, and wherein:
Referring to
Referring to
A very important aspect of this invention is the manner in which the self-propelled conveying assembly 5 advances into the mine opening 2 excavated by the mining machine 1. Unlike other systems currently in use, all modules of the conveying assembly 5, including all the intermediate modules 6 and the receiving module 4, have one or more propelling devices 13—driven axles with wheels are shown in the figures. The driven axles 13 are capable of generating a traction force to propel the conveying assembly either forward or backward. Driven axles 13 receive power from one or more drive shafts 14 driven from the drive module 7 located on the mining platform 15, through drives 16. As all the driven axles 13 are interconnected through the drive shafts 14, they are forced to advance or retreat at the same speed, regardless of the torque they may require. The whole conveying assembly 5 advances or retreats at the same speed without any appreciable push or pull within the conveying assembly 5, thus assuring a uniform and problem-free advance or retreat.
In a preferred embodiment of the present invention, individual conveyors 17 mounted within the intermediate modules 6 and the feeder 10 of the receiving module 4 also receive power from at least one drive shaft 18, which is driven from the drive module 7 located on the mining platform 15, through drives 19. Alternatively, individual drives, such as electric motors, located on modules 6 can be used to power modules 4, 6 and/or conveyors 17 and/or feeder 10.
The drive module 7 includes tram power drives 20 that power the drive shafts 14 and conveyor power drives 21 that power the drive shafts 18.
During the advancing or retrieval operation, all components of the conveying assembly 5, including the drive module 7, the intermediate modules 6 and the receiving module 4, are coupled together by couplings 22 while the drive shafts 14 are coupled together by drive couplings 23 and drive shafts 18 are coupled by drive couplings 24. When the intermediate modules 6 are coupled, the head ends 25 and the tail ends 25A of the conveyors 17 overlap in order to facilitate transfer of the material 26.
The mining platform 15 includes a discharge conveyor 27, the drive module 7, cable and hose winders 28, winches 29, a control room 30, an electrical room 31, a retractable ramp 32, and other required equipment and facilities. The retractable ramp 32 accommodates the elevation difference between the bottom deck 33 of the platform 15 and the bottom 34 of the seam 3. Tracks 35 or other modes of transportation are provided to facilitate positioning of the mining platform 15 with respect to the mine opening 2.
An important aspect of this invention is the method and apparatus of adding intermediate modules 6 to the conveying assembly 5. The extended bottom deck 33 includes a sliding table 36. Cargo handling equipment such as a commonly available forklift or a front-end loader is used to deposit an intermediate module 6 onto the sliding table 36. When the conveying assembly 5 advances into the mine opening 2 a full length of one intermediate module 6, the drive module 7 is disconnected from the last rearward intermediate module 6 and moved toward the discharge end 37 of the discharge conveyor 27, by a moving mechanism 38 attached to the drive module 7, thus generating a gap in the conveying assembly 5 that is greater than the length of an intermediate module 6. The sliding table 36 with an intermediate module 6 is moved sideways until the intermediate module 6 is lined up with the conveying assembly 5 at which point the drive module 7 is moved toward the new intermediate module 6 and all the components of the conveying assembly 5 are reconnected. As the drive shafts 14 and 19 are also reconnected through couplings 23 and 24, all axles 13 and conveyors 17 are powered and begin operating.
The intermediate modules 6 contain protective plates 39, 40 and 41 in order to protect mechanical and electrical components of the conveying assembly 5, including conveyor 17, electrical cables 42 and hoses 43. For this purpose, the electrical cables 42 and the hoses 43 are laid into structural trays 44. The sides 45 of the structural trays 44 also perform a function of guiding the conveying assembly 5 within the walls 9 of the mine opening 2.
Referring to
Referring to
Given three sides of any triangle, the angles can be determined from cosine and sine theorems as follows:
where in the first triangle (MNO): a=MN, b=OM, c=ON, α=⊃MON, β=⊃MNO, and γ=⊃OMN; and in the second triangle (NOP): a=OP, b=NP, c=ON, α=⊃ONP, β=⊃NOP, and γ=⊃OPN.
The navigation procedure is as follows:
Step 1: Stabilize O and P with side jacks 8 and move M and N with advancing cylinders 12. OM changes to OM1, ON to ON1, and NP to NP1. MN and OP remain fixed.
Step 2: Stabilize M and N with secondary jacks 101 and calculate new coordinates of M and N by triangulation.
Step 3: Release side jacks 8 and move O and P with advancing cylinders 12. OM1 changes to OM2, ON1 to ON2, and NP1 to NP2. MN and OP remain fixed.
Step 4: Stabilize O and P and calculate new coordinates of O and P by triangulation.
Repeat steps 1 through 4.
The above process measures actual distance traveled, rather than estimating it. Thus it allows the user to calculate the instantaneous position of mining machine 1 to an accuracy not obtainable with known position measuring means for mining machines. This allows the user to calculate the actual azimuth of the mining machine, in turn allowing for maximum material extraction from the mine. Using the above process to move mining machine 1 a distance of 1500 feet, while employing commercially available measuring means, will result in a position calculation that is accurate within three inches (0.167% error). Furthermore, the lack of complex measuring devices makes the present invention more reliable and less expensive than known apparatus.
Distance measuring means 103, 104, and 105 can take many forms. In the preferred embodiment, rotary potentiometers are used. Cables are attached between the points M, N, O, and P. As points M and O move relative to points N and P, the cables modify the potentiometers. By comparing the measurements before and after the modifications, the potentiometers can measure the amount and direction of movement. Other possible embodiments for the measuring means 103, 104, and 105 comprise linear potentiometers, proximity sensors, lasers, ultrasonic equipment, infrared sensors, hydraulic or pneumatic cylinders, and other known distance measuring apparatus.
Referring to
To remove intermediate module 6 from the conveying assembly 5, the operation is reversed. As the conveying assembly 5 trams out of the mine opening 2, raised portion 78 of the cam 77 lifts roller 75 and rotates hook 72 away from pin 76. The disengaged intermediate module 6 continues tramming onto the bottom deck 33 while the rest of the conveying assembly 5 remains stationary, in order to separate the disengaged intermediate module from the conveying assembly.
While the preferred embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not of limitation. It will be apparent to persons skilled in the relevant art that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus the present invention should not be limited by the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.
This application is a Continuation of U.S. patent application Ser. No. 09/734,665, filed Dec. 13, 2000, now U.S. Pat. No. 6,799,809, which is a Continuation-In-Part of U.S. patent application Ser. No. 09/250,689, filed Feb. 16, 1999, now U.S. Pat. No. 6,220,670. These documents are incorporated herein in their entireties.
Number | Name | Date | Kind |
---|---|---|---|
2826402 | Alspaugh et al. | Mar 1958 | A |
3456982 | Reilly | Jul 1969 | A |
3497055 | Oslakovic et al. | Feb 1970 | A |
3603264 | Arx | Sep 1971 | A |
4172615 | Hakes | Oct 1979 | A |
4192551 | Weimer et al. | Mar 1980 | A |
4226476 | Fairchild et al. | Oct 1980 | A |
4239289 | Justice et al. | Dec 1980 | A |
4365927 | Schenck | Dec 1982 | A |
4371211 | Snyder | Feb 1983 | A |
4390211 | Thompson | Jun 1983 | A |
4486050 | Snyder | Dec 1984 | A |
4583700 | Tschurbanoff | Apr 1986 | A |
4784257 | Doerr | Nov 1988 | A |
4846320 | Clarke | Jul 1989 | A |
4869358 | Chandler | Sep 1989 | A |
5112111 | Addington et al. | May 1992 | A |
5232269 | Addington et al. | Aug 1993 | A |
5246274 | Smith et al. | Sep 1993 | A |
5261729 | Addington et al. | Nov 1993 | A |
5582465 | Mraz | Dec 1996 | A |
5609397 | Marshall et al. | Mar 1997 | A |
5692807 | Zimmerman | Dec 1997 | A |
5810447 | Christopher et al. | Sep 1998 | A |
5890771 | Cass | Apr 1999 | A |
5938289 | Antoline et al. | Aug 1999 | A |
Number | Date | Country |
---|---|---|
1641100 | Feb 2000 | AU |
3722625 | Jan 1989 | DE |
0985082 | Dec 1998 | EP |
0974732 | Jan 2000 | EP |
477240 | Oct 1975 | SU |
488008 | Jan 1976 | SU |
705107 | Dec 1979 | SU |
1420178 | Aug 1988 | SU |
1347573 | May 1998 | SU |
Number | Date | Country | |
---|---|---|---|
20050040692 A1 | Feb 2005 | US |
Number | Date | Country | |
---|---|---|---|
Parent | 09734665 | Dec 2000 | US |
Child | 10953548 | US |
Number | Date | Country | |
---|---|---|---|
Parent | 09250689 | Feb 1999 | US |
Child | 09734665 | US |