Abstract:
A mining system for remotely mining ores and minerals which protects against falling rock and allows evacuation of a miner and conveying system in the case of a cave in. A shield is advanced into a mine. Within the shield, the miner and conveying system are also advanced into the mine independently from the shield. The shield may be used with miners and conveying systems in common use. The cover of the shield protects the miner and conveying system from falling rock. In the event of a cave in, the shield provides a cavity for safely removing the conveying system and miner from the mine.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority from U.S. Provisional Application Ser. No. 60/475,974, filed Jun. 5, 2003. The present application is related to copending U.S. patent application Ser. No. 10/862,255, entitled “Platform and Driver for Coal Mining System” and Ser. No. 10/862,255, entitled “Platform and Driver for Coal Mining System” and Ser. No. 10/862,205, entitled “Advancer for Coal Mining System” filed Jun. 7, 2004, both herein incorporated by reference in their entirety. 
    
    
     FIELD OF THE INVENTION 
     The invention is generally related to an improved system for coal mining. More particularly, the invention is directed to a shield system for high wall mining. 
     DESCRIPTION OF RELATED ART 
     Highwall mining is generally a method of mining whereby a remote controlled continuous miner is sent into a face of coal, or other ore, from an outside bench to mine or cut such ore out from under the overburden above. The continuous miner will generally cut out the ore in widths ranging from six to twelve feet in width and up to fourteen feet in height, depending on the size of miner used. As the miner is remotely controlled from outside into the ore, units for transferring the mined ore, called “cars” or “beams,” are sequentially sent into the mine, forming a continuous train and transferring the ore from car to car to the outside bench. Various methods are incorporated into the units for transferring the ore, including conveyors, chains and screws. Likewise various methods are used to power the transferring units, including electrical, hydraulics and/or mechanical drive shafts. The cars or beams are generally either coupled or pinned together, allowing some degree of deflection between them to improve negotiation of the rough surface in the mine. 
     On the outside of the mine, a launch platform is positioned to receive the transferred material as it is discharged from the rear car or beam and direct it either to a truck or stockpile via belt conveyors and/or chain conveyors. The launch platform also acts as a staging area to insert and retrieve the cars as needed and also act as a drive station to either hydraulically, electrically or mechanically drive or push the cars into the mine. 
     A major problem confronting the systems used today is roof material falling onto the transfer units and/or the miner and entrapping them. There are approximately forty systems operating today and most, if not all, have incurred major roof falls and entrapment requiring extensive downtime and cost to retrieve. Because of the complexity of the transfer units and continuous miners, it is critical to avoid damage or a complete loss of either. The transfer units range in length today from 20′ to 40′ and the systems include enough units to remotely drive the miner into the ore to depths of over 1000 feet; thus, as many as 50 units could be inside a mine at the time of a cave in, causing significant loss. Even if the units and miner are recoverable, significant work must be undertaken to recover them. A permit has to be issued to send men into an adjacent hole, mining, roof bolting and carrying ventilation back until they can cut through and cross-over to hopefully retrieve the miner and as many transfer units as possible. A number of units have been deemed a total loss and left under the mountain as the cost was to high to go after the units. 
     Additional roof problems are created by not controlling the direction of the miner precisely as it is driven into the mine. If the miner is not steered properly, the pillar or rib in between two mines can be cut. When the system cuts through the pillar exposing the width of two cuts, which can be as much as twelve feet in width each, twenty feet or more of unsupported roof is exposed. This greatly increases the potential for major roof falls, thus increasing the potential for entrapment. 
     Systems commonly used today require significant force to push the transfer units and miner into particularly deep mines. In deep mines, this force often causes the cars to buckle up and down throughout the hole binding the cars into the roof and floor. Because of this, the depth to which they can be pushed is limited. 
     Current disclosed methods of remote mining in ore deposits such as coal generally employ a mining machine that excavates mine openings to some distance from the seam exposure on the surface and a system for conveying the mined ore to the surface. In most of the present systems, the system for conveying consists of multiple conveyors or screws which are advanced into the mine openings from the surface. U.S. Pat. Nos. 6,644,753 and 6,220,670 issued to Mraz disclose a method and apparatus for mining of aggregate material from a seam which includes a mining apparatus and a self-propelled conveyor capable of advancing or retreating in the seam on its own power and an advancing and steering arrangement for the mining apparatus. 
     U.S. Pat. Nos. 5,112,111, 5,232,269, 5,261,729 and 5,364,171 to Addington et 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 et 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. U.S. Pat. No. 5,692,807 to Zimmerman discloses a guidance assembly for extending and retracting an assembly of conveyors into and out of the seam. U.S. Pat. No. 3,497,055 to Oslakovic et 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. U.S. Pat. No. 2,826,402 to Alspaugh et 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, the miner and material transfer units while operating underground are subject to roof falls and possible entrapment. Severe falls have caused both the continuous miner and material transfer units to be left underground and abandoned. Insurance costs have risen significantly to cover risk associated with possible loss due to rock falls. 
     Accordingly, it is an object of the present invention to provide a system for protecting a miner from falling rocks within a mine. 
     It is an object of this invention to provide a system for protecting material transfer units from falling rocks within a mine. 
     It is another object of the present invention to provide a system for removing a miner and/or material transfer units from within a mine in the event they become entrapped. 
     It is another object of the present invention to provide an improved mining system which reduces or eliminates down time caused by falling rocks or cave-ins. 
     It is a further object of the present invention to provide an improved mining system which provides increased control of the transfer units at greater mine depths. 
     It is yet a further object of the present invention to provide an improved mining system which provides greater directional control of the miner and material transfer units. 
     Finally, it is an object of the present invention to accomplish the foregoing objectives in a safe and cost effective manner. 
     SUMMARY OF THE INVENTION 
     A shielded mining system for mining ores and minerals remotely and removing the mined ores and minerals from the mine includes a miner, at least one material transfer unit for transporting the mined ores and minerals from the mine and shield having two side surfaces and a top surface. The shield may have a bottom surface which is flat or on wheels, depending on the floor of the mine. The shield provides protection to the miner and/or material transfer unit in a manner such that the miner and/or the material transfer unit can advance or retreat independently from the shield. The shield is advanced into the mine using electrical power, battery power, hydraulic power, a winch system or other appropriate means. Multiple shields may be connected together by, for example, a hook and pin system, so that a protected pathway is formed. Any material transfer unit such as multiple conveyor cars, a single winched car, a continuous belt system or other appropriate transport unit can be used. If multiple cars are used, they can be hooked together by, for example, a hook and pin system as well. 
     In a preferred embodiment of the present invention at least one shield in the shield system includes an advancing means. When the shield system is being pushed into a mine by an external platform/driver, having an advancing means on a forward shield keeps the shield system from buckling, and aids in pushing and steering the miner into the mine. 
     A method for remotely mining ores and minerals and for removing the mined ores and minerals from the mine, includes advancing a miner into a mine and independently advancing a first shield into the mine to protect the sides and top of the miner. A conveying system for conveying the mined ores and minerals is advanced into the mine and a second shield, preferably connected to the first shield, is independently advanced into the mine to protect the sides and top of the conveying system. Ores and/or minerals are excavated from the mine using the miner and removed from the mine using the conveying system. The conveying system may include supports which support the roof of the second shield 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an end view of the preferred embodiment of the present invention; 
         FIG. 1   a  is an end view of the preferred embodiment of the present invention with one type of material transfer unit inside. 
         FIG. 1   b  is an exploded view of  FIG. 1   a;    
         FIG. 1   c  is a side view of the preferred embodiment of the present invention with one type of material transfer unit inside; 
         FIGS. 1   d  and  1   e  are side views of the preferred embodiment of the present invention with one type of material transfer unit inside; 
         FIGS. 1   f  and  1   g  are side views of the present invention showing alternate means for moving the shield along the floor of the mine; 
         FIG. 2  is an end view of the present invention with one type of material transfer unit inside traveling on wheels; 
         FIG. 2   a  is an end view of the present invention with one type of material transfer unit inside traveling on rails; 
         FIG. 2   b  is an end view of an alternate embodiment of the present invention with one type of material transfer unit traveling inside on wheels pulled in and out by winch ropes; 
         FIG. 2   c  is an exploded view of the alternate embodiment of the present invention shown in  FIG. 2   b ; and 
         FIG. 3  is an end view of the present invention showing an alternate material transfer unit within. 
         FIG. 3  is a cross sectional side view of one side of a self advancing shield of the present invention with all cylinders in retracted position; 
         FIG. 4  is a cross sectional side view of one side of a self advancing shield of the present invention with gripping means extended; 
         FIG. 5  is a cross sectional side view of one side of a self advancing shield of the present invention with gripping means extended creating resistance and the outer beam being pushed forward; 
         FIG. 6  is a cross sectional side view of one side of a self advancing shield of the present invention with gripping means extended and outer beam extended the full stroke of the advancing means; 
         FIG. 7  is a cross sectional side view of one side of a self advancing shield of the present invention with gripping means fully retracted and ready for advancing means to retract pulling the inner beam forward; 
         FIG. 8  is a cross sectional view of a self advancing shield of the present invention wherein the actuating means is in an extended position. 
     
    
    
     ELEMENT LIST 
     
         
           145  Shield 
           401  Side supports of shield 
           403  Connecting pin for shield 
           405  Top plate of shield 
           408  Bottom plate of shield 
           409  Wheels 
           411  Mine floor 
           414  Mine roof 
           430  Side frame of truss 
           433  Top belt rollers 
           435  Bottom belt return roller 
           437  Top (carry) belt 
           439  Bottom (return) belt 
           441  Pin 
           443  Wheel roller 
           445  Spring (upwardly biased) 
           447  Roller guides (belt alignment) 
           450  Head pulley 
           451  Tail pulley 
           453  Hook 
           455  Keeper pin 
           501  Material transfer unit 
           503  Shuttle car on wheels 
           504  Movable transfer floor 
           505  Tire/wheel 
           507  Roller guides 
           508  Cable carriers 
           509  Rail 
           510  Rope guide 
           511  Railroad wheels 
           512  Non-movable floor 
           513  Wire 
           514  Opening 
           550  Continuous belt transfer unit 
       
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings,  FIGS. 1 ,  1   a ,  1   b ,  1   c ,  1   d ,  1   e ,  1   f ,  1   g ,  2 ,  2   a ,  2   b ,  2   c  and  3  show several embodiments of the present invention. As shown, the invention can be used with different types of material transfer unit, all independent and capable of being extracted from within the shield  145  in event of roof fall. Examples of several types of material transfer units are shown in the drawings and described below; however, these are not intended to be the only types of material transfer units which would be used with the present invention. 
       FIG. 1  shows an end view of the shield  145  without any material transfer unit within. 
       FIG. 1   a  shows an end view of a shield  145  with one type of material transfer unit  501 , a piggyback truss conveyor enclosed. The material transfer unit  501  is totally independent from the shield  145  and multiple conveyors may be hooked or tied together independent from the shield  145  so they can be extracted from within the shield  145 .  FIG. 1   a  shows the top plate  405  of the shield, the bottom plate  408  of the shield  145 , the mine floor  411 , the mine roof  414 , the side supports  401  of the shield, and the side support connecting pins  403  which can accept a hook  453  from another shield in order to connect multiple shields. Prior to insertion, when handling the shield  145  and material transfer unit  501  outside the mine, a temporary pin, or other appropriate apparatus, can be used to hold the material transfer unit  501  inside the shield  145 . Once the shield  145  and material transfer unit are ready to proceed into the mine, the pin can be removed. 
       FIG. 1   b  shows an exploded cross-sectional end view of the piggy-back truss conveyor type of material transfer unit  501  showing greater detail of the components including the truss side frame  430  which is a structure to support the conveyor independent of the shield  145 , the top belt rollers  433  to support the conveyor belt  437  carrying the material, the bottom belt rollers  435  to support the return belt  439 , roller guides  447  to keep the belt  437  &amp;  439  in alignment. Wheel rollers  443  are supported by heavy-duty springs  445  to help support the roof  405  as the material transfer unit  501  is pulled out from within the shield  145  in the event of a roof fall and subsequent extraction. The units  501  are preferably hooked together by placing a hook  453  over a pin  441 . 
       FIG. 1   c  shows a cross-sectional side view of the unit  501  with head pulley  450  and tail pulley  451  shown. The unit  501  is shown clearly situated within the shield  145  such that the shield  145  provides protection against rocks falling from the roof  414  of the mine and provides a cavity for withdrawing the unit  501  from the mine in the event of a roof cave in. 
       FIGS. 1   d  and  1   e  show the preferred means for connecting multiple units  501 . A connecting arm  453  from a first unit  501  fits over a pin  441  on a second unit  501 ′, connecting the end of the first unit  501  to the second unit  501 ′ and a keeper pin  455  is inserted above the connecting arm  453  to keep the arm  453  from rising off the pin  441 . 
       FIG. 1   d  further shows how the preferred connection allows for an angle of deflection between the ends of two units  501  and  501 ′ so the shield  145  and connected units  501  &amp;  501 ′ within can negotiate over a rolling mine floor  411 . 
     As shown in  FIGS. 1   f  and  1   g , the shield  145  may be constructed with a substantially flat bottom  408  or may include wheels  409  if the mine floor  411  conditions allow. By using wheels  409 , the force required to drive the shield  145  into the mine is reduced. Any bottom design which would allow the shield  145  to move through the mine is acceptable. A keeper pin  455  can be used to ensure that a hook (not shown) is retained on the connecting pin  403  when multiple shields  145  are connected. 
       FIG. 2  shows another type of material transfer unit that can be operated independently within the shield  145 , a shuttle car on wheels  503 . The shuttle car  503  can be electrically powered, battery powered or winched in and out carrying various amounts of ore tonnage depending on capacity. The floor  504  of the shuttle car  503  can be a moving floor using a chain or a belt and can be discharged out the rear onto a cross conveyor or onto a belly conveyor once on a platform. Rollers  507  will hold the car  503  and guide it through the shield  145  as it is powered or winched in and out. The shuttle car on wheels  503  can either run on rubber tire wheels  505  or on railroad type wheels  511  riding on rails  509  as shown in  FIGS. 2 and 2   a , respectively. 
       FIG. 2   b  shows a shuttle car on wheels  503  with a non-movable floor  512  that can be emptied once on a platform by a blade driving along the length of the car  503  which blade ejects or pushes the mined material off the rear of the car  503  onto a cross conveyor at the rear of the platform or onto a belly conveyor in the platform. The blade can be attached to driver/puller arms described in co-pending U.S. patent application Ser. No. 10/862,255, entitled “Platform And Driver For Coal Mining System”.  FIG. 2   b  also shows cable trey carriers  508  on either side of the shield  145  to carry a miner cable, water hose and control cable. Winch rope guides  510  are located on either side of the shield  145 . These guides  510  carry a wire rope  513  that runs up through sheaves close to the miner and returns back to the rear of the shuttle car  503  to pull it into the mine and up to the rear of miner so that ore may be off-loaded onto the car  503 . An opening  514  with rubber or other material to close once winch rope has passed through, allows a winch rope to brought up from under or from the side of the shield  145  when inserting the shield  145  into the push area without stopping an ongoing cycle; thus a shield  145  can be inserted into the line of shields and hooked up while the shuttle car  503  is inside being loaded and there is no loss of time between cycles. 
       FIG. 2   c  is an exploded view of the shield  145  side supports  401  showing wire rope  513  riding in winch rope guides  510 . 
       FIG. 3  shows yet another type of material transfer unit that can be used within the shield  145 . A continuous belt  550 , using a belt storage magazine feeding the belt  550  from the platform, is driven by means of a drive located on the platform. A tail pulley is attached behind the miner, or the second shield, and the conveyor belt  550  is fed in as the miner advances. When the shields  145  are lowered over the continuous belt  550 , the conveyor truss is split and pulled to either side as shown in  FIG. 3 . Once the belt  550  is in place, the truss sides are closed and are centered around the belt to form the support for the belt  550  such that mined material can be transported out of the mine on the belt  550 . The bottom of the truss structure has plates which, when closed, fill in the void in the bottom opened to allow the shielded car to be lowered from the top. Inserting a shield  145  over the top of the continuous belt  550  will not stop the train of shields  145  from advancing forward during the lowering of additional shields  145  and the hooking of the shielded cars  145  from one to another, thus there is no work stoppage. The tail pulley structure attached to the miner and the independent truss frames hooked together can be pulled out from within and is structurally strong enough to pull the miner out from within the shields  145  if needed. Likewise a continuous chain driven from outside could transfer the material to the outside. 
       FIG. 4  and  FIG. 5  shows a preferred embodiment of the shield  145  of the present invention wherein the shield  145  comprises a self advancing shield  146 . The self advancing shield  146  is preferably located at the forward end of a series of shields, closest to the miner. The self advancing shield  146  works in conjunction with a platform driver which pushes the system from outside the mine. The advantage of using a self advancing shield is that it prevents buckling of the system which could occur if the system was advanced by the platform alone. The self advancing shield  146  is adapted to surround mining machinery  300 . Rollers  507  between the advancer shield  145  and the mining machinery  300  allow the mining machinery  300  to be pulled through the shield  145  structure and then out to an external platform in the event of a roof fall thus preventing entrapment of the mining machinery  300 . 
     The self advancing shield  146  comprises at least two beams or tubes (box beams); one slightly smaller inner beam  925  slides independently within an outer beam  923 . The outer beam  923  comprises the top surface  405  and side supports  401  of the shield  145 . The inner beam  925  comprises actuating means  913 ,  917 ,  919  which act to press gripping means  911 ,  916 ,  918  into any combination of floor, roof, and sidewalls of the mine. The actuating means  913 ,  917 ,  919  are any actuating means known to those of average skill in the art, and are preferably hydraulic cylinders. When in an extended position, the actuating means  913 ,  917 ,  919  pass through openings  931 ,  933 ,  935  in the outer beam  923  and press the gripping means  911 ,  916 ,  918  into any combination of floor, roof, and sidewalls of the mine. The gripping means  911 ,  916 ,  918  are any gripping means known to those of skill in the art to grip a mine wall, and are preferably stab plates. When the gripping means  911 ,  916 ,  918  are engaging the mine, an advancing means  921  extends the outer beam  923 . The advancing means is any advancing means known to those of average skill in the art and is preferably a hydraulic cylinder. The gripping means  911 ,  916 ,  918  are then withdrawn back through the openings  931 ,  933 ,  935  in the outer beam  923 . The advancing means  921  is then retracted, pulling the shield  145  forward. 
     While the description above refers to particular embodiments of the present invention, it will be understood that many modifications may be made without departing from the spirit thereof. The accompanying claims are intended to cover such modifications as would fall within the true scope and spirit of the present invention.