Abstract:
A drum-type miner having a plurality of water jet nozzles which cut independently of the mechanical bits is disclosed. The drum-type miner may configured in either a hard-head or a ripper-chain design. The unique combination of mechanical and hydraulic cutting results in higher rates of penetration and improved productivity. The nozzles in one embodiment are supplied on a transversely mounted strut and are supplied with high-pressure fluid through two independent water channels in the strut. The nozzles may be configured in different directions, such that the high-pressure fluid may be directed in several directions simultaneously, or configured to direct the high-pressure fluid in one direction only. Moreover, because the mining face is pre-scored by the water jets, the amount of wear on both the mechanical bits and the motors may be significantly reduced.

Description:
RELATED APPLICATION (S) 
     This application is a Continuation-In-Part of prior application Ser. No. 09/540,044 filed on Mar. 31, 2000, now U.S. Pat. No. 6,409,276. 
    
    
     FIELD OF THE INVENTION 
     The present invention generally pertains to mineral mining processes and, more particularly, but not by way of limitation, to a mining system particularly adapted for the recovery of coal from coal seams. 
     History of the Related Art 
     The recovery of coal, ore, or other material from mineral bearing strata or seams has been the subject of technological development for centuries. Among the more conventional mining techniques, drum-type mining systems have found industry acceptance. Drum-type mining machines typically utilize a cutting head having a rotating cylinder or drum with a plurality of mechanical bits on an exterior surface for cutting into the mineral bearing material. The dislodged material is permitted to fall to the floor of the mining area, gathered up, and transported to the mining surface via conveyors or other transportation means. 
     Although drum-type mining machines have proven effective, conventional drum-type cutting systems generally rely solely on a mechanical cutting action which subjects motors and bits to considerable wear and produces significant amounts of dust. Also, to increase the productivity of conventional mechanical cutting machines will normally require the installation of larger and heavier cutting motors on the miner to produce the additional power needed. 
     Thus, there is a need for a reliable mining system which addresses the limitations of the above-described conventional mining systems and which achieves higher rates of penetration and improved productivity. 
     SUMMARY OF THE INVENTION 
     The present invention overcomes the foregoing and other problems with a dual-channel water jet assisted, drum-type mining system which positions a plurality of high pressure water jets receiving water from a first channel to cut the mining face in two directions independently of mechanical bits, and positions a plurality of high pressure water jets receiving water from a second channel to allow sumping in another direction during downward shear. This combination of mechanical and hydraulic cutting results in higher rates of penetration and improved productivity. The high pressure water used in cutting may be pumped via a hose line or other conduit from a remote location. Alternatively, a high pressure water pump may be located on the chassis of the miner. Of course, this means that the cutting motors on the drum-type miner itself can be much smaller than the motors used to generate equivalent production by conventional means. Moreover, because the mining face is pre-scored by the water jets, the amount of wear on both the mechanical bits and the motors may be significantly reduced. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a more complete understanding of the present invention, and for further objects and advantages thereof, reference is made to the following Detailed Description taken in conjunction with the accompanying drawings in which: 
     FIG. 1 is a side elevational view of a drum-type cutting head contacting a mineral seam; 
     FIG. 2 is a simplified, top plan view of a drum-type mining system; 
     FIG. 3 a  is a cutaway, side elevational view of a hard-head cutting head for drum-type mining systems; 
     FIG. 3 b  is a cutaway, side elevational view of a ripper-chain cutting head for drum-type mining systems; 
     FIG. 4 is a side elevational view of a cutting drum with mechanical bits mounted on an exterior surface and showing an effective cutting diameter; 
     FIG. 5 is a front elevational view of a cutting drum showing a typical scrolling pattern to the bits; 
     FIG. 6 a  is a side elevational view of a water jet assisted cutting head of the present invention showing a high pressure fluid conduit mounted tangentially above and below the drum; 
     FIG. 6 b  is a side elevational view of a water jet assisted cutting head of the present invention showing a high pressure fluid conduit shaped to fit between the exterior surface of the drum and the effective cutting diameter as defined by the mechanical bits; 
     FIG. 7 is a top plan view of a hard-head embodiment of the water jet assisted cutting head of the present invention. 
     FIG. 8 is a top plan view of a ripper-chain embodiment of the water jet assisted cutting head of the present invention. 
     FIG. 9 a  is a fragmentary, top plan view of an exemplary strut having two exemplary water conduits therein; 
     FIG. 9 b  is a side elevational cross-sectional view of a larger extent of the strut of FIG. 9 a  taken along line  9   b — 9   b  having an exemplary first water conduit therein; 
     FIG. 9 c  is a side elevational cross-sectional view of a larger extent of the strut of FIG. 9 a  taken along line  9   c — 9   c  having an exemplary second water conduit therein; 
     FIG. 9 d  is an enlarged, end elevational, partial cross-sectional view taken along line  9   d — 9   d  of FIG. 9 a;    
     FIG. 10 is an enlarged, side elevational cross-sectional view of exemplary water inlets for the first and second water conduits of FIGS. 9 b  and  9   c;    
     FIGS. 11 a - 11   b  are side elevational views of the strut perimeter of FIGS. 9 b  and  9   c  with selected nozzles allowing high-pressure fluid therethrough; and 
     FIG. 12 is a schematic view of an exemplary flow system for the strut of FIG. 9 a.    
    
    
     DETAILED DESCRIPTION 
     It has been discovered that the use of water-jet assistance during mining operations assist in the liberation of the coal from the working face of the mineral seam. The high-pressure streams of water actually penetrate and cut into the coal surface independent of and beyond the reach of the mechanical bits used during the drilling operation. These slots or grooves in the mineral face, cut by the high-pressure water jets, reduce the amount of energy required for mechanical excavation by pre-fracturing the coal and providing additional free faces for the coal to break as it is impacted by the mechanical bits. It has also been discovered that the use of multi-directional water-jets can aid in the pre-fracturing of the coal and mineral deposits. Such systems will be described in more detail below. 
     High-pressure water jets as described below, in conjunction with the water provided to the working area also have the significant benefit of greatly reducing the amount of coal dust liberated during the mining process. The amount and pressure of water provided to each of the water nozzles  185  may further be varied independently, depending on the specific application. 
     The preferred embodiment of the present invention and its advantages are best understood by referring to FIGS. 1-11 b  of the drawings, like numerals being used for like and corresponding parts in each of the various drawings. 
     The mechanical cutting capabilities of drum-type continuous miners, used for mining coal and other minerals, can be supplemented by the inclusion of high-pressure water jets. Unlike borer-type miners where mechanical bits continuously contact the cutting face, the mechanical bits on a drum miner cut coal or contact the excavation point less than 50% of the circumference of the drum. As best seen in FIG. 1, less than half of the mechanical bits  105  on the drum-type cutting head  110  typically contact the cutting surface  25  at one time. For example, the bits denoted by reference number  30  are in contact with and cutting the mining face  25  while the other bits  35  will not contact the mineral seam until the drum is rotated almost 180°. This also complicates the addition of water jets to the rotating drum  110  itself, and substantially reduces their effectiveness because, if mounted this way, at least half of the nozzles would be directed away from the mining face  25  at any one time. 
     As best seen in FIG. 2, a simplified drum-type continuous miner  100  has a horizontal cylinder or drum  110  with its axis of rotation  111  perpendicular to the center line  55  of the opening or entry being developed  50 . As the miner  100  is advanced toward the mining face  25 , the drum is turned in a top-forward direction of rotation  112  to achieve a cutting action with the mechanical bits, not shown. Also, the drum  110  is generally moved up and down in a vertical plane, not shown, to increase the height of the opening  50  and overall production. 
     With reference now to FIGS. 3 a  and  3   b  together, the cylinder  110  is rotatably mounted to an arm or a boom  120 . The electric motors  130  to rotate the drum  110  may be mounted in the body of the miner, not shown, or the boom  120 , with the energy being transferred from the motors  130  to the drum  110  using either: (1) rotating drive shafts  140  housed within fixed supports  150 , as shown in FIG. 3A, or (2) gears  160  located behind and beneath a cutter or ripper chain  170 , seen in FIG. 3B, which wraps around the drum  110 , a central portion of which has gear-like teeth  175  for engaging the underside of the chain  170 , and an idler located on the support boom  120 . Either of these methods uses the rotating mechanical energy of an electric motor  130  to cause the drum  110  to rotate, top forward at a speed of approximately 60 revolutions per minute. 
     As best seen in FIG. 4, the effective cutting diameter  115  as defined by the cutting bits  105  is greater than the diameter  116  of the smooth exterior surface of the drum  110 . This provides an off-set or distance  117  within which water jet nozzles and high pressure conduits may be mounted as in FIGS. 6A and 6B. The distance  117  may be calculated by subtracting the drum radius from the effective cutting radius. This distance  117  will typically range from about 3 to about 8 inches, but it is understood that this distance  117  is dependent only on the size of the drum  110  and the length of the bits  105  and bit blocks  107  selected and is not limited only to this particular range. 
     As illustrated in FIG. 5, mechanical bits  105  are typically attached to the smooth exterior surface of the drum  110  in positions that create various patterns as it rotates. This is referred to as the scroll  106  of the bits  105 . The spacing of the track, made by the mechanical bits  105  on the cutting surface  25 , varies, depending on the longitudinal spacing of the mechanical bits  105 . Typically, the track spacing or bit lace spacing will be from about 1.5 to about 3 inches, or more. These mechanical bits  105  are removable. They are inserted in bit lugs or bit blocks  107 , which are in turn welded solidly to the exterior surface of the drum  110 . The mechanical bits  105  can be routinely removed from this bit lug  107  and replaced as they wear. 
     The plumbing necessary to provide high-pressure water at sufficient flows to water jets can take advantage of the bit spacing or lacing, and the distance  117  between the smooth exterior surface of the drum  110  and the actual cutting diameter of the bits  105 . Water jets can be preferably mounted in two different ways. 
     As shown in FIG. 6A, a first embodiment would involve the addition of a high pressure water hose, not shown, and metal piping  180 , which is run from the miner body or the boom  120  and mounted tangent to the upper and lower surfaces of the drum  110 . This piping  180 , positioned within the effective cutting diameter  115  of the cutting head  110 , can actually extend beyond the center line of the cylinder  110 , so that the water jet nozzles  185 , are only slightly back from the mechanical bits  105  in contact with the mineral seam, not shown. 
     As illustrated in FIG. 6B, a second embodiment would involve the addition of a high pressure water hose, not shown, and metal piping  180 , which is run from the miner body or the boom  120  and may be curved or shaped to fit about the circumference of and just beyond the smooth exterior surface of the drum  110 . The piping or conduits  180  are positioned within the effective cutting diameter  115  of the cutting head  110 , and can be tapped and fitted with nozzles  185  which are located between the surface of the drum  110  and the cutting face  25  of the material being mined. Thus, the distance between the coal face  25  and the nozzles  185  is effectively minimized. 
     Either of these two exemplary embodiments would provide rigidly mounted high-pressure conduits  180  having water jet nozzles  185  at a very close distance to the solid coal being cut. The jet nozzles  185  provide high-pressure water which assists mining by cutting and creating a vertical slot or groove in the coal face from roof to floor as the drum  110  is moved up and down in a conventional cutting motion. These vertical grooves effectively pre-score the coal face and make it far easier for the mechanical bits  105  to then fracture the coal. 
     As shown in FIG. 7, an alternative method of mounting water jets  185  would involve running high-pressure water lines  180  at least partially within the existing support struts  150  of a hard-head miner, introduced in FIG.  3 A. Various techniques are used to rotate the drum  110 . The support struts  150  are rigid, non-rotating members that may or may not contain drive shafts for rotating the cylinder  110 . The plumbing  180  can provide high-pressure water and sufficient flow to several water jets  185  mounted on the front, or core breaker edge  190  of these support struts  150 . These support struts  150  are non-rotating, while the actual segmented cylinder, or drum  110 , rotates on either side of the support strut  150 . Since these support struts  150  must be sufficiently wide to contain mechanical parts like a drive shaft, there is usually a zone of solid, uncut coal, referred to as a core, which forms between the two rotating drums  110 . The front edge  190  of the support strut  150  typically contains bits or sharp points  195 , see FIG. 3A, designed to break or cut the core, which remains between the two rotating cylinders. The high-pressure water jets  185  can be mounted in several positions on this core breaker  190 . This would also place the water jets  185  close to the surface being cut mechanically by the bits  105 . In this and other mounting applications, either fixed- or swivel-mounted (not shown) water-jets can be used. 
     Turning now to FIG. 8, in conjunction with FIG. 3B, a ripper-chain embodiment miner of the present invention is illustrated. The drum  110  is segmented or formed of three sections which are linked together by a spline, axle or other means to turn as a single unit about a common axis of rotation. The central section has gear-like teeth  175 , shown in FIG. 3B, which engage the underside of a ripper chain  170 . The chain  170  is looped around the drum  110 , and drive gears  160 . As the drive gears  160  turn, the chain  170  and the drum  110  are rotated top-forward to mine coal. 
     As shown in FIG. 8, the chain  170  and the outer sections of the drum  110  have mechanical bits on their exterior surfaces. As shown in FIGS. 6A and 6B, rigid conduits  180  which are tapped to supply water nozzles  185  may be located above or below the cutting portions of the drum  110  or may be curved to fit completely around the drum  110 . Although the depicted embodiment has four conduits or tubes  180  around the drum  110 , it is understood that these rigid tubes  180  may be provided in any number which does not hinder the cutting drum  110 . If necessary, mechanical bits  105  may even be removed from the drum  100  to provide the lateral spacing required for mounting the high pressure conduits or tubes  180 . 
     The application of high-pressure water jets  185  to the drum-type continuous miner  100  allows additional hydraulic cutting power to be provided for the excavation of coal or other materials, beyond the power provided by the mechanical cutting head motors. This additional power is provided by high-pressure water pumps, not shown, which are powered by additional motors which may be located remotely from the continuous miner  100 . Of course, if small enough, these high-pressure pumps, not shown, could also be located on the continuous miner itself. 
     The water jets  185  assist in the liberation of the coal from the working face. The high-pressure streams of water, which are produced by the water jets  185 , actually penetrate and cut into the coal surface independent of and beyond the reach of the mechanical bits  105 . These slots, or grooves, cut by the high-pressure water jets  185  reduce the amount of energy required for mechanical excavation by pre-fracturing the coal and providing additional free faces for the coal to break as it is impacted by the mechanical bits  105 . 
     The high-pressure water jets  185  and the water provided to the working area also have the significant benefit of greatly reducing the amount of coal dust liberated during the mining process. The amount and pressure of water provided to each of the water nozzles  185  may further be varied independently, depending on the specific application. 
     By way of example only, Table 1 is provided to better illustrate how the use water jet assisted cutting on a drum-type miner may result in significant improvements in both penetration rate and production. For comparison purposes, a conventional drum-type miner in a ripper-chain configuration was first tested using mechanical cutting alone. The miner was then fitted with a water jet system according to the present invention. The water jets were supplied at about 6,000 psi and about 150-170 gallons per minute. Data from repeated trials were then averaged to produce Table 1. It is notable that the production with water jet assistance was nearly double that of the conventional mechanical bit drum-type miner. 
     
       
         
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                   
                 Penetration 
                 Production 
                 Cutting Motor 
               
               
                 Technique 
                 (ft/min) 
                 (tons/hour) 
                 (amps) 
               
               
                   
               
             
             
               
                 Mechanical 
                 1.00 
                 227 
                 125-130 
               
               
                 Bits Only 
               
               
                 Mechanical + 
                 1.83 
                 415 
                 100 
               
               
                 Water Jets 
               
               
                   
               
             
          
         
       
     
     Repeated tests were also made to determine the best configuration and orientation of water jets  185 . It was found that the water jets  185  on a single metal conduit  180  should focus cutting to produce a vertical groove or slot rather than random erosion of the entire face. 
     Referring now to FIG. 9A, there is shown a top plan view of an exemplary water jet assisted cutting head strut  900  of the present invention. FIGS. 9B-9D show the strut  900  in more detail. For example, FIG. 9B shows a side-elevational cross-sectional view of the water jet assisted cutting head strut  900  having a first high pressure fluid conduit  910  therein. The strut  900  may be shaped to fit between the exterior surface of the drum (not shown in this Figure) and the effective cutting diameter as defined by the mechanical bits. However, field testing has proved that the outer diameter of the strut  900  should be no closer than the outer edge of the mechanical bit block. If the strut  900  is closer than this, it will impede the cutting effectiveness of the mechanical bit. 
     As can be seen from FIG. 9B, the fluid conduit  910  fluidly connects to a plurality of nozzles  920  positioned at a predetermined angle with respect to the conduit  910 . The nozzles  920  may secure to the conduit  910  via threads  930  and the like. The nozzles  920  are removable, and in certain embodiments the positioning of the nozzles  920  may be adjusted to change the angle of the nozzles  920  relative to the strut  900  depending on the mineral deposit height and hardness. 
     Referring now to FIG. 9C, there is shown a side-elevational cross-sectional view of the strut  900  having a second internal fluid conduit  940  therein. The second fluid conduit  940  similarly fluidly connects with a plurality of nozzles  950 , which are alternately configured in either a first direction or a second direction. The number and directions of the nozzle configuration may be dependent on the height and hardness of mineral deposit to be cut and the approach of cutting, sumping, and shearing with the drum cutting head. The first fluid conduit  910  does not fluidly communicate with the second fluid conduit  940 , such that the nozzles  920  of the first fluid conduit  910  may allow fluid therethrough independently of the nozzles  950  of the second fluid conduit  940 . The nozzles  950  of the second fluid conduit  940  may be offset to avoid the first fluid conduit  910  in certain embodiments. 
     Referring now to FIG. 9D, there is shown a side-elevational partial cross-sectional end view of the strut  900  of FIGS. 9A-9C. Conduits  910 ,  940  are shown traversing through the strut  900 . 
     Referring now to FIG. 10, there is shown inlet connector  1000  in a side-elevational cross-sectional view. Inlet connector  1000  has respective inlets  1005 ,  1010  for the first fluid conduit  910  and the second fluid conduit  940  respectively. As can be seen in FIG. 10, the first fluid conduit  910  and the second fluid conduit  940  are separated from one another and are not fluidly connected. Threads  1020  may be provided at inlets  1005 ,  1010  for connection to a fluid source (not shown). Likewise, threads  1030  may be provided at a top portion  1040  and a bottom portion  1050  of the inlet connector  1000  for mechanically connecting the inlet connector  1000  to an external structure. 
     Referring now to FIGS. 11A and 11B, there is shown side profile views of the strut  900  of FIGS. 9B and 9C. Different water-jet spray configurations are shown. For example, FIG. 11 a  shows a first spray configuration wherein all nozzles  920 ,  950  are allowing high-pressure fluid therethrough in the direction indicated by arrows  1100 , which may be referred to as sump mode. FIG. 11B shows a second spray configuration, referred to as shear mode, wherein high pressure fluid flows through the nozzles  920  in the direction indicated by arrows  1110 . It is to be understood that the angles of the nozzles  920 ,  950  may be adjusted, such as through the use of different nozzles, different coupling means, or through different positioning of the nozzles  920 ,  950 . It is also to be understood that the fluid flow through the conduits may be controlled such that flow may be directed at certain angles with respect to the strut  900  and through desired nozzles only. 
     Referring now to FIG. 12, there is shown a schematic of a flow system  1200  for water jet assisted cutting head struts  900 . The struts  900  are transversely mounted to the drum  1210 . The struts  900  are fluidly connected to a manifold  1220  via fluid lines  1240  or the like. The manifold  1220  may contain the inlet connector  1000  (FIG. 10) for the respective strut  900 , or the inlet connector  1000  may be placed in a region near the drum  1210  or other suitable locations. A flow divider  1230  is provided to divide flow from a high pressure fluid source (not shown) through the manifold  1220  and into a respective fluid conduit  940  of a respective strut  900 . The manifold  1220  may be adapted to control fluid flow therethrough and into a respective strut  900 . 
     The operation of strut  900  having dual fluid conduits can be described as follows: first, a preselected seam of mineral deposits is identified, and the cutting head having at least one strut  900  thereon is advanced toward the seam. High pressure fluid is passed through one or more conduits in the strut  900  and flows outwardly therefrom. The mechanical bits are actuated and engage the seam after the high pressure fluid has contacted the seam, which is referred herein as sumping. The cutting head is allowed to penetrate into the seam at least the distance about equal to ½ of the diameter of the cutting head. Next, the cutting head is moved downwardly with respect to the seam while the high pressure fluid is adjusted to flow in shear-mode, wherein fluid flows only through one of the two conduits in the strut  900 . After reaching the base of the seam, fluid flow is terminated and the miner backs up to allow cleaning of the floor, then advances back to the coal face. The cycle may then be repeated. 
     The use of the dual channel water jet assisted cutting head provides significant advantages over cutting heads of prior systems. By way of example only, Table 2 is provided to better illustrate how the use of the dual channel jet assisted cutting on a drum-type miner may result in significant improvements in both penetration rate and production. For comparison purposes, conventional drum-type miner in a ripper-chain configuration was first tested using mechanical cutting alone. The miner was then fitted with a dual channel water jet system according to the present invention. The water jets were supplied at about 6,000 PSI and about 50-150 gallons per minute. 
     
       
         
               
               
               
               
             
           
               
                 TABLE 2 
               
               
                   
               
               
                   
                   
                 Penetration 
                   
               
               
                   
                 Flow 
                 Rate 
                 Production 
               
               
                 Technique 
                 (gpm) 
                 (ft/min) 
                 (tons/hour) 
               
               
                   
               
             
             
               
                 Mechanical-no 
                 — 
                 2.67 
                 560 
               
               
                 water assist-six 
               
               
                 cutting bits 
               
               
                 removed 
               
               
                 Mechanical bits 
                 — 
                 2.77 
                 581 
               
               
                 only-six cutting 
               
               
                 bits added from 
               
               
                 prior 
               
               
                 configuration 
               
               
                 Dual channel water 
                 48 
                 3.30 
                 693 
               
               
                 jet assist-two 
               
               
                 0.043″ nozzles on 
               
               
                 top and two 0.043″ 
               
               
                 nozzles on bottom 
               
               
                 Dual channel water 
                 78 
                 3.67 
                 769 
               
               
                 jet assist-two 
               
               
                 0.055″ nozzles on 
               
               
                 top and two 0.055″ 
               
               
                 nozzles on bottom 
               
               
                 Dual channel water 
                 150 
                 4.00 
                 840 
               
               
                 jet assist with 
               
               
                 four 0.055″ 
               
               
                 nozzles on top and 
               
               
                 one 0.109″ nozzle 
               
               
                 bottom 
               
               
                   
               
             
          
         
       
     
     As can be seen from Table 2, significant improvement is realized when nozzles from both conduits are actuated in phased-configurations (e.g. nozzles from both conduits are actuated simultaneously; only nozzles from one conduit are actuated). The size of the nozzles controls water flow and is likewise shown to affect production. 
     It is thus believed that the operation and construction of the present invention will be apparent from the foregoing description of a preferred embodiment. While the device shown is described as being preferred, it will be apparent to a person of ordinary skill in the art that various changes and modifications may be made therein without departing from the spirit and scope of the invention, as defined in the following claims. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred embodiments contained herein.