The present invention relates to mining equipment, and particularly continuous underground mining machines.
Traditionally, excavation of hard rock in the mining and construction industries, has taken one of either two forms, explosive excavation or rolling edge disc cutter excavation. Explosive mining entails drilling a pattern of holes of relatively small diameter into the rock being excavated, and loading those holes with explosives. The explosives are then detonated in a sequence designed to fragment the required volume of rock for subsequent removal by suitable loading and transport equipment. However, the relatively unpredictable size distribution of the rock product formed complicates downstream processing.
Mechanical fragmentation of rock eliminates the use of explosives; however, rolling edge cutters require the application of very large forces to crush and fragment the rock under excavation. On a conventional underground mining machine, a cutter head liberates material from a mine wall. The material falls to the mine floor under the cutter head and is directed onto a conveyor for transportation away from the mine wall. This operation produces large amounts of dust and debris and results in loss of mined material.
In one embodiment, the invention provides a mining machine for cutting material from a mine wall. The mining machine includes a cutting head that is movable to engage the mine wall, a vacuum duct positioned proximate the cutting head and including an inlet for receiving the material that is cut from the mine wall, and a sizer for reducing the size of material that passes into the vacuum duct, the sizer being positioned proximate the inlet.
In another embodiment, the invention provides a material handling system for a mining machine, the mining machine including a cutting head. The material handling system includes: a suction source including a material collector; a vacuum conduit extending between the suction source and the mining machine, the vacuum conduit including an inlet positioned adjacent the cutting head, the inlet receiving material that is cut from a mine wall by the cutting head, the vacuum conduit being in fluid communication with the suction source to transport the cut material from the inlet to the material collector; and a sizer for reducing the size of material that passes into the vacuum duct, the sizer being positioned proximate the inlet.
In yet another embodiment, the invention provides a method for processing material that is cut by a mining machine including a cutting head. The method includes: cutting the material from a mine wall; reducing the cut material to a desired size as the cut material is guided toward an inlet of a vacuum conduit; and transporting the cut material through the vacuum conduit to a material collector.
In still another embodiment, the invention provides a mining machine for cutting material from a mine wall. The mining machine includes: a cutting head that is movable to engage the mine wall, the cutting head being pivotable about an axis oriented substantially perpendicular to the mine floor; and a vacuum duct positioned proximate the cutting head, the vacuum duct including an inlet for receiving the material that is cut from the mine wall.
Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.
Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. The terms “mounted,” “connected” and “coupled” are used broadly and encompass both direct and indirect mounting, connecting and coupling. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings, and can include electrical or hydraulic connections or couplings, whether direct or indirect. Also, electronic communications and notifications may be performed using any known means including direct connections, wireless connections, etc.
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In the embodiment shown in
The disc cutter assemblies 66 are driven to move in an eccentric manner. This is accomplished, for instance, by driving the disc cutter assemblies 66 using a drive shaft (not shown) having a first portion defining a first axis of rotation and a second portion defining a second axis of rotation that is radially offset from the first axis of rotation. The magnitude of eccentric movement is proportional to the amount of radial offset between the axis of rotation of each portion of the shaft. In one embodiment, the amount of offset is a few millimeters, and the disc cutter assembly 66 is driven eccentrically through a relatively small amplitude at a high frequency, such as approximately 3000 RPM.
The eccentric movement of the disc cutter assemblies 66 creates a jackhammer-like action against the mineral to be mined, causing tensile failure of the rock so that chips of rock are displaced from the rock surface. The force required to produce tensile failure in the rock is an order of magnitude less than that required by conventional rolling edge disc cutters to remove the same amount of rock. The action of the disc cutter assembly 66 against the under face is similar to that of a chisel in developing tensile stresses in a brittle material, such as rock, which is caused effectively to fail in tension. In another embodiment, the disc cutter 66 also nutates such that the axis of rotation moves in a sinusoidal manner as the disc cutter 66 oscillates. This is accomplished by making the axis about which the disc cutter drive shaft rotates angularly offset from a disc cutter housing.
The mining machine 14 is operated by advancing the arm 30 toward the material to be mined a first incremental distance, pivoting the arm 30 to cut the material, and then advancing the arm 30 toward the material to be mined a second incremental distance. During operation, the lower disc cutter assembly 66b is the first to contact the mineral to be mined when the arm 30 is pivoted in a first direction (clockwise as viewed from the top of the arm 30 in
The material handling system 10 may be used in combination with the continuous mining machine 14 described above, or may be used in combination with a mining machine as described in U.S. Pat. No. 7,934,776, filed Aug. 31, 2007, the entire contents of which are incorporated herein by reference. The material handling system 10 is described in detail below.
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In the illustrated embodiment, the retaining brackets 586 are arranged in pairs such that one retaining bracket 586 is coupled to one side of the shaft 578 and another retaining bracket 586 is coupled to another side of the shaft 578 diametrically opposed to the one side. The pairs of brackets 586 are positioned at various points along the length of the shaft 578. The retaining brackets 586 are angularly offset with respect to one another such that each hammer 582 is in a different angular position from the other hammers 582. In another embodiment, the sizer 546 may include fewer or more retaining brackets 586 and hammers 582. Also, the retaining brackets 586 may be configured in a manner other than in pairs, and the retaining brackets 586 may be positioned in parallel alignment along the shaft 78 such that the hammers 582 are parallel to each other during rotation.
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In other embodiments, a secondary duct is mounted on the cutter head 26. The secondary duct is mounted on a side plate on the leading side 522 of the cutter head 26. The secondary duct is activated during a return swing of the cutter head 26 to remove any remaining cut material. In yet another embodiment, the vacuum duct 542 may be mounted on an extended and/or secondary boom configuration or on a secondary cutter head.
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As rock is cut from the mine wall, the skirt 622 and high-pressure water from the spray blocks 614, 618 contain cut material within an area proximate the mine wall. The primary spray-block 614 clears cut material below a lower cutting disc assembly 66b, while the secondary spray-block 618 entrains the material that builds up under the cutter head 26. The spray-blocks 614, 618 urge the material toward the vacuum duct 542. The cut material is guided along the skirt 622 and is fed into the vacuum duct 542, whereby the rotating hammers 582 impact and break apart the rock. Suction provided by the dewatering plant 634 (
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The vacuum system 534 is controlled from the machine 14 by a vacuum system controller (not shown) that is linked wirelessly to a machine controller. In further embodiments, other connection methods may be used. The vacuum system 534 is capable of being started and stopped both manually, via remote, and automatically during an automatic cutting sequence. The vacuum system 534 is also capable of starting locally, such as on a starter box.
When an auto-cut sequence is selected, a “start” command signal is sent to the vacuum system controller and cutting continues only if a “vacuum running” feedback signal is given from the vacuum system controller. In the event that communication is lost between the vacuum system controller and the machine controller, while the vacuum system 534 is running, the vacuum system 534 will be maintained in the running state, but can be stopped locally.
Vacuum pressure is monitored during the cutting cycle. If the vacuum pressure drops below a pre-determined limit, or if the vacuum system 534 is stopped, then the control system permits the current auto-cut sequence to complete. When the auto-cut sequence is completed, an auto-cut stop sequence is initiated.
Thus, the invention may provide, among other things, a material handling system for entraining and sizing material that is cut by a continuous mining machine and conveying it away from the mine wall. The system may include a sizer for reduce the material to a desired size.
Various independent features and independent advantages of the invention are set forth in the following claims.
This application claims the benefit of prior-filed, co-pending U.S. Provisional Application No. 61/514,542, filed Aug. 3, 2011, U.S. Provisional Patent Application No. 61/514,543, filed Aug. 3, 2011, and U.S. Provisional Patent Application No. 61/514,566, filed Aug. 3, 2011, the entire contents of all of which are hereby incorporated by reference. The present application also incorporates by reference the entire contents of PCT Patent Application No. PCT/US2012/049532, filed Aug. 3, 2012 and titled “AUTOMATED OPERATIONS OF A MINING MACHINE” and U.S. Non-Provisional patent application Ser. No. 13/566,150, filed Aug. 3, 2012 and titled “STABILIZATION SYSTEM FOR MINING MACHINE”.
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