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Publication numberUS3817336 A
Publication typeGrant
Publication dateJun 18, 1974
Filing dateJan 21, 1972
Priority dateApr 6, 1970
Publication numberUS 3817336 A, US 3817336A, US-A-3817336, US3817336 A, US3817336A
InventorsSears H
Original AssigneeSears H
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method and apparatus for determination of ore sampling location
US 3817336 A
Abstract  available in
Images(5)
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Claims  available in
Description  (OCR text may contain errors)

United States Patent 1 1 Sears [52] US. Cl. 175/61, 175/45 [51] Int. Cl E211) 7/04 [58] Field Of Search 175/44, 45, 61, 73-76 [56] References Cited UNITED STATES PATENTS 2180.851 4/1942 Ranney 175/61 3.229.375 H1966 Crake et al. 175/45 2.565.794 8/1951 Young 175/61 3.362.751) 1/1968 Carnegie 175/45 Primary Examiner-Marvin A. Champion 111 3,817,336 [451 Jim 18,1974

Assistant ExaminerLawrence J. Staab Attorney, Agent, or Firm-Rey Eilers 5 7 ABSTRACT A sensing device which defines the terminal position and inclination of a curved prospect hole drilled from a passage in a mine by indicating the distance, slope and deflection, from initial position and azimuth, of progressive points along the hole.

An in-hole sensor is provided with a plurality of potentiometers mounted on mutually perpendicular axes to which are attached pendulums. Anglar changes in inclination and attitude of the sensor with reference to the pendulums vertical position cause related electrical outputs from the potentiometers which can be read as degrees by a readout instrument. Other potentiometers therein have their electrical outputs altered to an extent proportional to the deflection of the hole.

According to the method of the invention cross-section samples may be taken from the ground surrounding and in the plane of mine workings by drilling curved prospect holes from within existing mine openings.

12 Claims, 12 Drawing Figures PATENTEDJUM is 1924 SHEET 1 BF 5 FIG E FIG 2 METHOD AND APPARATUS FOR DETERMINATION OF ORE SAMPLING LOCATION CROSS-REFERENCE TO RELATED APPLICATION This is a continuation-in-part of my application Ser. No. 25,885 filed Apr. 6, I970 and now abandoned, which is a division of my application Ser. No. 685,671 that was filed Nov. 24, I967 and that issued Mar. 23, 1971 as US. Pat. No. 3,57l,937.

BACKGROUND OF THE INVENTION This invention relates to a sensing device adapted for use in mining and to a method of ore sampling.

In mining, it is often necessary to determine whether a particular ore vein will continue in a certain direction. In the event that a vein should change grade or thickness in a direction relative to an existing mine working, such knowledge is obviously valuable so that any extensions or expansions of the existing mine workings may be made in such a direction to yield the greatest ore recovery.

For example, after ore has been mined and the working has proceeded in a certain direction, it is desired to determine whether a continuation of the mining in this direction would result in still further recovery ofore. In the past, one such method has been the drilling downwardly of prospect holes from the surface of the earth, in line with a projection of the existing mine opening. In this way, samples of earth in the same line and the existing mine level are obtained, analyzed, and the probability for further recovery of ore from the projection determined. However, such a method may sometimes be somewhat cumbersome and expensive, particularly if the mine working is deep within the earth.

Summary of the Invention: According to the present invention, prospect holes are drilled from the existing mine workings for relatively short distances. By means of down-hole drills, curved prospect holes are drilled and a plurality may radiate out from an end or any desired portion of an existing mine working, all in order to sample the ground surrounding and in the same plane to determine the proper direction for extension or enlargement of the mine workings for further recovery of ore.

An orientation sensing device is employed in practicing this invention and is placed in a prospect hole, the distance and direction from the origin of the prospect hole to its terminus may be determined. Hence, samples may be taken from a curved prospect hole and this invention used to determine the location of the ore samples relative to extant mine workings.

In the drawings:

FIG. I is a schematic view ofa mine working showing two conventional. vertical prospect holes and also showing two curved prospect holes employed in the practice of this invention,

FIG. 2 is a view similar to FIG. 1, showing the sensing device in initial position and in one progressive position,

FIG. 3 is a cross-sectional view of the sensing device of this invention,

FIG. 4 is a view along line 44 in FIG. 3,

FIG. 5 is a cross-sectional view of a portion of the probe extension of FIG. 3,

FIG. 6 is a schematic diagram of a null balance circuit, and of a readout instrument adapted to yield digital values from the electrical signals put out by the sensor of FIG. 3,

FIG. 7 is a diagrammatic showing of a number of partially-straight, partially-curved prospect holes,

FIG. 8 is a sectional view of a curved prospect hole, and it shows drilling equipment in that hole,

FIG. 9 is an exploded view of the collar shown in FIG.

FIG. 10 is a perspective view ofa mine working and of drilling equipment therein,

FIG. 11 is a longitudinal section, on a scale larger than that of FIG. 10, and it is taken along the broken plane indicated by the broken line 11-11 in FIG. 12, and

FIG. 12 is a sectional view, on the scale of FIG. 11, and it is taken along the plane indicated by the line l2-l2 in FIG. 11.

Turning now to the drawings, FIG. 1 illustrates a mining operation wherein a working 10 is located deep within the earth, and is illustrated as proceeding to the right within an ore vein 12. The area between the dashed lines 14 represents an imaginary extension or projection of the ore. The numerals I6 and 18 denote curved prospect borings in the earth extending from the working 10. It will be observed that the end of prospect bore 16 has intersected a portion of ore vein 12, while the end of prospect bore 18 intersects only the projection of the working 10, the vein 12, for illustrative purposes, having run out.

The numerals 20 and 22 denote vertical prospect holes which would be required according to a prior art practice. It will be observed that the holes 20 and 22 intersect the imagined horizontal projection 14 of the workings 10. According to this prior art practice, ore samples are taken from the holes 20 and 22 in order to determine the extent of the vein 12 in the illustrated direction. It will be apparent that the depth of the sample borings 20 and 22 may be extremely large, particularly as compared with the length of the borings l6 and 18.

Turning now to FIG. 2 of the drawings, the numeral 10 again represents a horizontal portion of mine workings and the number 16 again denotes a curved prospect hole, here illustrated of only limited extent. The number 24 denotes a generally cylindrical sensing device which forms a portion of this invention and is supported at its rearward end by a roller guide 36 and at the other end connected to a rod 26, the ends of the lat ter being secured to roller probe guides 28 and 70. In general, the diameter of the sensing element 24 and the probe guides 28, 36 and is smaller than the diameter of the prospect hole 16. FIG. 4 denotes a coil of stiffly flexible tubing, disposed on a reel 30 and attached to the sensor roller guide 36 by fitting 6, which is the means by which the sensor is inserted into the withdrawn from the prospect bore.

FIG. 8 represents the power source and readout instrument case which may, with 30, be conveniently placed on the floor of the workings 10.

Alpha, the angle of initial deflection of the hole, exists between the longitudinal axis of the sensor housing 24 and the axis of the guided position of the forward probe 26. The dotted position of the sensor assembly is shown to illustrate a position on the progressive survey of the entire prospect hole.

Turning now to FIG. 3 of the drawings, the numeral 31 denotes a cylindrical or tubular element which, together with end plugs 32 and 34. define the shell or casing of sensing element 24. Numeral 36 denotes generally a rear supporting roller guide assembly, including a tubular element 38 preferably threaded into the rear closure cap 34 and provided on its periphery with a plurality of radially extending wheels 37 adapted to engage the walls of the prospect hole and into which is screwed the end fitting 6 of the coil of flexible tubing 30 by means of which the sensor assembly is inserted into and withdrawn from the prospect hole. The numeral 40 denotes a cable carried within flexible tubing 4 and adapted to carry a plurality of electrical wires which lead to the assemblage 30 and convey the electrical output signals from the instruments within 24 presently to be described.

The numeral 42 denotes generally a supporting grid preferably formed of sheet material and positioned within cylinder 3l between ends 32 and 34. A plurality of elongated bolts 44 extend from one plug to the other and pass through the supporting grid assembly 42. A first potentiometer 46 is provided with a weight 48 in the general form ofa pendulum and suitably secured to its shaft, all supported by grid 42. It will be observed that tilting the potentiometer 46 will result in a swing ing movement of pendulum 48 thereby actuating the rotatable arm of potentiometer 46. The electrical leads from potentiometer 46 are fed to the cable 40.

The numeral 50 denotes a second electrical potentiometer having its corresponding pendulum 52 also secured to its shaft. Again, the electrical leads from potentiometer 50 are carried within cable 40. It will be observed that rolling the sensor axially will result in movement of the pendulum 52 and turning of the shaft of the potentiometer.

Near the right portion of sensor 24 two additional potentiometers 54 and 56 (note also FIG. 4) are carried by the grid support 42. Each of the shafts of these potentiometers is coupled to a lever denoted by 58 for potentiometer 54 and by 60 for potentiometer 56. The end of a deflection shaft 62 is positioned, as best illustrated at FIG. 4, between the levers 58 and 60, the levers being biased to assure continued contact against the end of shaft 62. Again, the electrical leads from the potentiometers 54 and 60 are carried outward through the cable 40.

The numeral 64 denotes a threaded coupling positioned within the central aperture of end plug 32 of the sensor 24. A rubber sleeve 68 is positioned at one of its ends over the sleeve coupling 64 and at its other end is received over a forward guide portion assembly denoted generally by the numeral 70. A plurality of angu- Iarly disposed wheels 72 are positioned around the periphery of 70.

The left portion of rod 26 is fastened. as by threading. into the assembly 70 and the right portion extends into a similar assembly which defines the guide 28 of FIG. 3. A plurality of wheels 76 are provided around the periphery of the guide 28 at spaced angular positions. Reference again to FIG. 3 of the drawings discloses the relationship between the elements illustrated in FIGS. 3, 4 and 5. The sensor 24 is rearwardly supported by the assembly 36 and forwardly supported by the assembly 70. With insertion of the sensor assembly of FIG. 3 into the prospect hole 16, the forward guide 28 will follow the curved prospect hole and the angle between rod 26 and the sensing element 24 will indicate the degree of curvature of the hole in the plane of the drawings. As the rod 26 assumes various angular orientations with respect to sensor 24, the shaft 62 will pivot about an enlarged portion 67 on its periphery, with this pivoting motion being transmitted to the end of the rod 62 which rotates the shafts to which the levers 58 and 60 are connected in the two forward potentiometers 54 and 56. It will be apparent that from a knowledge of the distance between assemblies 28 and 70, and the distance between pivot 67 and the end of rod 62 which contacts the two forward potentiometer levers, values of the angle alpha illustrated at FIG. 2 may be computed from changes in the electrical resistance of po tentiometers 54 and 56.

While the angle alpha illustrated at FIG. 2 of the drawings lies in the plane of the drawing, the prospect hole 16 may deviate from this plane and such deviation will be apparent in the relationships between the electrical resistivities of the associated potentiometers 50, 54 and 56. The relationship of electrical resistances of the same three potentiometers is employed to deduce the curvature of any tested increment of prospect hole 16. Electrical signals from potentiometer 46 are employed to get the longitudinal inclination of the prospect hole with an accuracy dependent on how near its axis is to horizontal. From this, and knowing the length of cable 40 fed into the bore 16, the location of the very end of the prospect hole 16 may be calculated and accordingly ore samples obtained from the end of the hole may be located relative to existing mine workings. Thus, before continuing a mine working in a certain direction, test borings are made to determinee the extent and quality of veins adjacent existing mine workings. One drill which has been found suitable for drilling prospect holes such as 16 is that illustrated in my US. Pat. No. 3,084,673, although any specific down-hole drill may be so employed.

Reference to FIG. 6 ofthe drawings discloses one circuit which may be employed to utilize the information given by the potentiometer changes to determine the terminal location of a prospect hole 16.

In FIG. 6, the reference numerals 100, 102, 104 and 106 denote the potentiometers 46, 50, 54 and 56 of FIGS. 3 and 4, and are here assigned different numerals for purposes of schematic illustration. The wires leading from these potentiometers are contained in the cable 40 of FIG. 3. The numeral 108 schematically denotes a dial face graduated in degrees from zero to 360 fastened to the shaft of associated potentiometer 110 adapted to be rotated to give a reading in degrees. The numeral 112 denotes a polarity sensitive relay whose movable contact 113 closes one circuit used to energize a light 114 which indicates too little resistance in the read out circuit in the case that the dial 108 and hence the potentiometer shaft has been turned too far to the left. Another light 116 becomes illuminated when the dial 108 has been turned too far to the right thus adding too much resistance in the readout sensing circuit. The numeral 118, together with its associated but unnumbered diodes, resistances, and capacitors designates an amplifying circuit which amplifies very low voltages when the circuit is near null or balanced, so that changes in the lights 114 and 116 will occur with a sensitivity within one-half a degree on the dial 108. In general, the sensing circuit is of the null balance type and when a null condition is obtained, the reading on dial 108 corresponds to the angular position of one of the selected potentiometers in the probe 24 of FIG. 3.

The numerals 120, 122, 124, 126 and 128 represent adjustable resistances which are used to calibrate and balance the individual sensing circuits. The numeral 130 denotes a switch to select the particular potentiometer 100 to 106 whose angular position will be found by rotation of the dial face 108. The numerals 132, 134 and 136 denote batteries and the numeral 138 denotes a battery test meter. The remaining unnumbered diodes, capacitors and resistances are employed to stabilize, to amplify and to filter the various electrical voltages. Inasmuch as the circuit illustrated in FIG. 6 is given by way of example only, as representing one null type balance circuit which may be employed, further detailed description of the circuit will not be offered. In use, the various potentiometers within the sensor 24 of FIG. 3 may be read by circuits such as shown in FIG. 6 during the insertion and movement of the assembly shown at FIG. 3 into the prospect hole 16 to thereby determine, as earlier discussed, the direction and hence the final position of the terminal portion of any prospect hole. This illustration of the principles of this invention has used rotary potentiometers for determining the angular and special orientation of the sensor assembly 24. Other transducers such as rotary linear variable differential transformers may be employed in this configuration and with the use of pendulums and levers to give linear movement proportional to the angular and deflection aspects of the sensor 24, both rectilinear potentiometers and rectilinear variable differential transformers are suitable.

Referring particularly to FIG. 8, the numeral 150 denotes the end face of a working 148 which can be essentially identical to the working in FIGS. 1 and 2; although the working 148 extends from right to left whereas the working 10 extends from left to right. The numeral 152 denotes a curved prospect boring which is generally comparable to the curved prospect borings l6 and 18 of FIGS. 1 and 2', although the curved prospect boring 152 extends from right to left whereas the curved prospect borings l6 and 18 extend from left to right. The numeral 154 denotes a down-hole drill which can be ofthe type shown in US. Pat. No. 3,084,683 or US. Pat. No. 3,361,2l9. A flexible coupling 156 connects the rear end of the down-hole drill 154 with a section 158 of drill rod.

A bushing 160, which is generally elliptical in side elevation, as shown particularly by FIGS. 8 and 10, is mounted on the section 158 of drill rod. If desired, that bushing could be pressed onto at section of drill rod; but that bushing will preferably be mounted on that section of drill rod so it can not shift axially of, but can rotate relative to, that section of drill rod. The numeral 164 denotes a further section of drill rod which is located within the curved prospect boring 152 to the right of the section 158 of drill rod. The numeral 166 denotes a driving section of drill rod which has one end thereof extending into the curved prospect boring 152, and which has the other end thereof disposed outwardly of that curved prospect boring.

A collar 168 encircles the driving section 166 of drill rod; and that collar has its inner end wedged into the portion of the curved prospect boring 152 which communicates with the working 148. The collar 168 has a downwardly-directed arm 170; and it has perforated ears 172, as shown particularly by FIG. 9. A generallysquare gasket 174 of flexible material is shaped to abut the outer face of the collar 168 and to fit between the openings in the perforated ears 172. A gland 176, which has openings therein that can be set in register with the openings in the perforated ears 172 of the collar 168, has a large central opening therein. That large central opening in that gasket is made just large enough to snugly receive the cross section of a section of drill rod. Although the gasket 174 could be made from different materials, it preferably is made from a length of rubber belt; because the material of which rubber belts are made is tough'and has good wearresisting qualities. The numeral 182 denotes wing bolts which can extend through the openings in the gland 176 to seat in the threaded openings of the perforated ears 172 of the collar 168. Tightening of the wing nuts 182 will tend to force the gasket 174 into sealing engagement with any section of drill rod that extends through the large opening in that gasket.

The numeral 184 to FIG. 10 denotes a standard and usual drill head which can grip and rotate a section of drill rod. The rotative forces which the drill head 184 will apply to the section 166 of drill rod will enable that drill rod to act through the drill rods to which it is connected to rotate the down-hole drill 154 within the curved prospect boring 152. The drilling action of the down-hole drill 154 is not a rotary action but, instead. is a percussive action. As a result, the rotative forces which the drill head 184 must apply to the section 166 of drill rod, and thus to the other sections of drill rod and to the down-hole drill 154, are very much smaller than the rotative forces which a drill head must apply to a rotary drill. The rotary forces which the drill head 184 applies to the section 166 of drill rod, and thus to the other sections of drill rod and to the down-hole drill 154, need only be great enough to cause that drill to rotate sufficiently to keep that drill from binding or jamming within the curved prospect boring 152.

The numerals 186 and 188 denotes jacks which are disposed within the working 148, and which have the upper ends thereof abutting the ceiling of that working and which have the lower ends thereof abutting plates 189 that rest on the floor of that working. Each of those jacks will be lengthened until the upper end thereof bears so solidly against the ceiling of the working 148 that it is fixedly held against shifting relative to the other jack and relative to that working.

The numeral 190 denotes a mounting frame which is secured to both of the jacks 186 and 188 adjacent the upper ends of those jacks. A pneumatic cylinder 192 is supported by the mounting frame 190; and a piston rod 194 has one end thereof secured to the piston within that cylinder, and has the other end thereof extending outwardly of that cylinder into engagement with the drill head 184. The piston rod 194 will be suitably secured to a flange on the drill head 184 so that drill head and that piston rod will reciprocate as a unit. The pneumatic cylinder 192 is a double-acting cylinder; and thus can cause the piston rod 194 to force the drill head 184 to move toward and away from the curved prospect boring 152. The numeral 196 denotes an air valve which has a handle 198; and that handle can be adjusted to control the flow of compressed air to the drill head 184 via a hose 208. The numeral 200 denotes a further air valve which is part of an air distributor on the mounting frame 190; and that valve has a handle 202.

The numeral 204 denotes a supporting bracket which is mounted on the jack 186 below the level of the mounting frame 190. That supporting bracket slidably holds a pipe 206 while acting to confine that pipe against radially-directed movement. As shown in FIG. 10, the inner end of the pipe 206 is mechanically coupled to the outer end of the section 166 of drill rod which passes through the drill head 184. The outer end of the pipe 206 is connected to an air hose 210 by a connector 211 which permits rotation of that pipe without requiring rotation of that air hose. The inlet of the valve 196 is connected to one of the outlets of the air distributor 195 by a pipe 209.

An air line 212 has the left-hand end thereof connected to a source, not shown, of compressed air; and it has the right-hand end thereof connected to a manually-operated air valve 214. A line oiler 216 is connected to the outlet of the air valve 214', and a fitting 217 connects the outlet of the line oiler 216 to flexible air hoses 218 and 220. The air hose 218 extends to the inlet of the valve 200; but the air hose 220 extends to the inlet port of a T-fltting 222. An air hose 224 extends from one outlet port of the T-fitting 222 to the air distributor 195; and an air hose 226 extends from the other outlet port of that T-fitting to an air valve 228 adjacent a water pump 230. The outlet of the valve 228 is connected to the inlet of that water pump and a flexiblc hose 232 extends from the outlet of that water pump to an inlet of the air distributor 195. An air hose 233 extends from a control valve, not shown, to one end of the pneumatic cylinder 192; and a further air hose, not shown, extends from that control valve to the other end of that pneumatic cylinder. Appropriate actuation of that control valve will cause the piston rod 194 to move the drill head 184 toward or away from the curved prospect boring 152.

The numeral 234 denotes a dust sample collector of standard and usual form. That dust sample collector will be set on the floor of the working 148 a short distance from the plats 189 which underlie the jacks 186 and 188. A large diameter hose 236 extends from the arm 170 of the collar 168 to the inlet of the dust sample collector 234. That dust sample collector is selfventing, and hence an exhaust hose or line is not needed for that dust sample collector. 101 The numeral 238 denotes a platform which is secured to the jack 186 by a clamp. That platform can be set at any desired level above the floor of the working 148, but it will preferably be set at a level which will enable a workman to easily reach and manipulate the handles 198 and 202 of the valves 196 and 200, respectively. Also, that platform will preferably be set at a level which will enable the workman to reach the handle of the control valve, not shown, that controls the supply of air to the opposite ends of the pneumatic cylinder 192. Further, that platform will preferably be set at a level which will enable the workman to disconnect the pipe 206 from the last section of drill rod, to connect an additional section of drill rod to that last section of drill rod, to free the jaws of the drill head 184 from that last section of drill rod, to cause the control valve to move the drill head 184 toward the bracket 204 until it is telescoped over the additional section of drill rod, to cause those jaws to clamp onto that additional section of drill rod, and then to connect the end of the pipe 204 to the free end of that additional section of drill rod.

A water-supplying line, not shown, can be connected to the water pump 230 to provide the water which that pump will cause to pass through the hose 232 to the air distributor 195. That water will be suitably introduced into the air in the hose 210, and it will successively pass through the pipe 206 and the various sections of drill rod to the down-hole drill 154. That water can be used to soak dust loose from the walls of the curved prospect boring 152.

Referring to FIGS. 11 and 12, the numeral 156 generally denotes the flexible coupling which is shown on a smaller scale in FIGS. 8 and 10. That coupling includes a tube which has an external thread 141 at the left-hand thereof, which has a radially-extending flange 142 at the right-hand thereof, which has axiallyextending splines 143 spaced a short distance to the left of that radially-extending flange, and which has a thin, annular, axially-directed projection 144 at the righthand face thereof. The flexible coupling 156 also includes a socket 145 which has an internal thread 146 at the right-hand end thereof, which has an external thread 147 at the left-hand end thereof, which has a shoulder 139 at the right-hand end of the external thread 147, and which has a thin, annular, axiallydirected projection 149 at the left-hand face thereof. The thin, annular, axially-directed projection 149 on the socket 145 is in register with and extends toward- ,but stops short of, the thin, annular, axially-directed projection 144 on the tube 140. An annulus 161, of a resilient material such as rubber, is disposed between the confronting faces of the tube 140 and of the socket 145; and the thin, annular, axially-directed projections 144 and 149 hold that annulus in position between those confronting faces.

The flexible coupling 156 additionally includes a sleeve 151 which has an internal thread 153 at the right-hand end thereof that can mate with the external thread 147 on the socket 145. Also, that sleeve has a shoulder 155 which can abut the left-hand face of the radially-extending flange 142 on the tube 140, and can thereby hold the right-hand face of that tube in engagement with the resilient annulus 161. Further, the sleeve 151 has a number of axially-extending grooves 157 therein which accommodate the axially-extending splines 143 on the tube 140; and, as shown particularly by FIG. 11, those grooves extend through to the shoulder 155. The numeral 159 denotes the inner surface of the portion of the sleeve 151 in which the grooves 157 are formed.

The internal thread 146 on the socket 145 will mate with the external thread on the left-hand end of the section 158 of the drill rod string shown in HQ 8. The external thread 141 on the left-hand end of the tube 140 will mate with an internal thread in the right-hand end of the down-hole drill 154 of FIGS. 8 and 10. The internal thread 153 of the sleeve 15] will mate with the external thread 147 on the socket 145 to hold the righthand end of that sleeve in engagement with the shoulder 139 on the socket 145, and to hold the shoulder 155 in engagement with the radially-extending flange 142. At such time, the tube 140 and the socket 145 will be in end-to-end relation, the resilient annulus 161 will be held by the thin, annular, axially-directed projections 144 and 149, and the splines 143 on that tube will be disposed within the grooves 157 of the sleeve 151. Those splines will coact with the side walls of those grooves to rotate the tube 140 and thereby rotate the down-hole drill 154.

The inner surface 159 of the grooved portion of the sleeve 151 is machined to provide a predetermined annular gap between it and those portions of the outer surface of the tube 140 which are located between the splines 143. That annular gap determines the extent to which the axis of the tube 140 can tilt relative to the axis of the socket 145; and thereby controls the maximum angle of deflection between the axis of the downhole drill 154 and the axis of the section 158 of drill rod string in FIG. 8. In doing so, that annular gap determines the radius of curvature of the prospect boring holes drilled by the down-hole drill 154 whenever the flexible coupling 156 is interposed between that downhole drill and that drill rod section. An annular gap having a thickness in the range of forty-eight to sixty thousandths of an inch has been found to provide a radius of curvature of about 125 feet for the curved prospect boring 152. By decreasing the thickness of that annular gap, it is possible to increase the radius of curvature for that curved prospect boring. While it is theoretically possible to decrease the radius of curvature for that curved prospect boring below I25 feet, by increasing the thickness of that annular gap, frictional resistance and abrasion problems increase excessively when that radius of curvature is so decreased.

In performing the method of the present invention, the workman will use the down-hole drill 154 or another drill to form the initial portion of the curved prospect boring 152. Although the axis of that initial portion of that boring can be set at different angles relative to the axis of the vein 249, which extends outwardly beyond the end face 150 ofthe working 148 as shown by FIGS. 7 and 8, the axis ofthat initial portion will preferably be set at an angle of from to 60 relative to the axis of that vein. Once the initial portion of the curved prospect boring 152 is deep enough to fully accommodate the down-hole drill 154, the flexible coupling 156 and the bushing 160, the workman will telescope that bushing over the section 152 of drill rod, and the pneumatic cylinder 192 will be actuated one or more times until that downhole drill, that flexible coupling, and that bushing are in the position indicated by FIG. 10.

At such time, the forward end of the collar 168 will be tightly wedged into position within the initial portion of the curved prospect boring 152. Air then will flow through the pipe 212, the valve 214, and the line oiler 216 to the fitting 217; and then some of that air will pass through hose 218, valve 200, air distributor 195, hose 210, connector 211, pipe 206, section 166 of drill rod, drill rod section 158, and flexible coupling 156 to the down-hole drill 154. Further air will flow through the hose 220 to the T-fitting 222 and then via the hose 224 and air distributor 195 to the control valve, not shown. for the pneumatic cylinder 192. Additional air will flow through pipe 209, valve 196, and hose 208 to the drill head 184 to cause that drill head to rotate the section 166 of drill rod.

The air which passes to the down-hole drill 154 will cause the end face of that drill to repeatedly strike the inner end of the curved prospect boring 152 in the manner in which the bit of a pneumatic drill repeatedly strikes the surface against which it is held. Air pressure which is supplied to the right-hand end of the pneumatc cylinder 192 will act through the piston rod 194 and the drill head 184 to cause the various sections of drill rod to apply a steady force to the down-hole drill 154 which will continuously urge the cutting face of that downhole drill into drilling engagement with the inner end of the curved prospect boring 152. The additional air,

The air which exhausts from the down-hole drill 154 will pass through the curved prospect boring 152 toward the collar 168. Because the inner end of that collar is wedged tightly into the initial portion of that curved prospect opening, little or no air can escape through the joint between that collar and that initial portion. Because the gasket 174 tightly encircles the last section of drill rod, little or no air can escape along the surface of that drill rod. Consequently, the air which is exhausted from the down-hole drill 154 will pass through the collar 168, will pass downwardly through the arm 170 of that collar, and then will pass through the hose 236 into the dust. sample collector 234. That dust sample collector has water and suitable filters therein to intercept and collect the dust carried by the air passing downwardly through the hose 236. That dust can be removed from that collector on a periodic basis as a sample; and that sample can be analyzed to provide precise information as to the grade or value of the rock comprising the extension of the vein in which the working 148, from which the curved prospect boring 152 is being bored, is located.

The down-hole drill 154 is relatively heavy; and it will respond to the force of gravity to tilt its axis and the axis of the tube 140 of the flexible coupling 156 downwardly relative to the axis of the socket 45 of that flexible coupling and relative to the axis of the drill rod section 158, as shown by FIG. 8. Also, that down-hole drill will apply a downwardly-directed force to the forward end of the first section of drill rod; and that downwardly-directed force will tend to bend the first section of drill rod downwardly toward the lower surface of the curved prospect boring 152. If the bushing 160 were not present, some portion of the first section of drill rod would engage that lower surface; and the distance, between the down-hole drill 154 and the portion of the first section of drill rod which engaged the lower surface of the curved prospect boring 152, would tend to vary from time to time. Any variations in that distance could be objectionable, because they could change the radius of the arc defined by the curved prospect boring 152, and they could expose long portions of the first section of drill rod to severe bending forces. However, when the bushing 160 is present, it acts as a fulcrum; and thereby keeps all or substantially all portions of the first section of drill rod from engaging the lower surface of the curved prospect boring 152. Importantly, that bushing holds the flexible coupling 156 and the rear end of the down-hole drill 154 up out of engagement with the lower surface of that curved prospect boring 152, and thereby enables that down-hole drill to assume an inclination which is fixed by the thickness of the annular gap between the inner surface 159 of the grooved portion of the sleeve 151 and those portions of the outer surface of the tube which are located between the splines 143. In addition, that bushing fixes the distance between the down-hole drill 154 and the first point along the lower surface of the curved prospect boring 152 where the drill rod string receives support from that lower surface.

The flexible coupling 156 will transmit rotational forces from the adjacent section 158 of drill rod to the down-hole drill 154, while permitting that down-hole drill to dispose its forward end below the level of its rear end. As a result, the down-hole drill 154 will automatically bore the prospect hole 152 so that prospect hole is curved. By providing various thicknesses for the annular gap between the inner surface 159 of the grooved portion of the sleeve I51 and those portions of the outer surface of the tube 140 which are located between those splines 143, it is theoretically possible to drill holes having various radii of curvature or at various rates of change of inclination, and thus to vary the minimum distance at which it is possible to intersect an extension of the vein 249. However, the smallest practical and economical radius of curvature attainable with the down-hole drill 156 is about 125 feet.

If an extension of a vein 249 is to be intersected by a curved prospect boring at an angle of 45, and if that curved prospect boring is to have a constant radius of curvature of 125 feet, the minimum distance between the starting point of that curved prospect boring and the point of intersection with the vein extension 249 will be 175 feet as shown by FIG. 7. If an extension 249 of a vein should be intersected by a curved prospect boring at an angle of 45 at a point spaced from the starting point of that curved prospect boring a distance of three hundred feet along that vein extension, 21 flexible coupling 156 could be used which had a thinner annular gap between the inner surface 159 of the grooved portion of the sleeve 151 and those portions of the outer surface ofthe tube 140 which are located between the splines 143; because such a flexible coupling would cause the down-hole drill 154 to provide a larger radius of curvature for that curved prospect boring. However, to save the cost of buying and stocking several flexible couplings with specifically different thicknesses of annular gap, such a prospect boring would preferably be drilled with an initial straight portion 242 inclined at an angle of l and with a final curved portion 244 having a radius of curvature of 125 feet shown by FIG. 7. Similarly, if an extension 249 ofa vein should be intersected by a curved prospect boring at an angle of 45 at a point spaced from the starting point of that curved prospect boring at distance of four hundred feet along that vein extension, a flexible coupling I56 could be used which had an even thinner annular gap between the inner surface 159 of the grooved portion of the sleeve I51 and those portions of the outer surface of the tube 140 which are located between the splines I43; because such a flexible joint would cause the down-hole drill 154 to provide an even larger radius of curvature for that curved prospect boring. However. such a prospect boring would preferably be drilled with an initial straight portion 248 inclined at an angle of 8 and with a final curved portion 250 having a radius of curvature of 125 feet as shown by FIG. 7. It will be I noted that in each case, the maximum lateral spacing between the prospect boring and the extension of the vein is only about 40 feet. This is desirable; because it means that the total length of each prospect boring is not unduly greater than the distance along that vein extension between the starting point of that prospect boring and the point of intersection.

To drill the initial straight portion 242, or to drill the initial straight portion 248, the flexible coupling 156 will be replaced by a concentric rigid coupling, and the bushing 160 will be removed. Where that is done, the down-hole drill 154 will form the desired straight portion 242 or the desired straight portion 248. After the desired straight portion has been formed, the flexible coupling 156 will be used to connect the down-hole drill 154 to the section 158 of drill rod, and the bushing 160 will be set in position on that section of drill rod. Thereafter, that flexible coupling and that bushing will automatically cause that down-hole drill to provide a radius of curvature of feet for the final curved portion of the prospect boring.

By providing the bushing and the flexible coupling 156, the present invention makes it possible for the down-hole drill 154 to establish a desired radius of curvature for the curved portion of a prospect boring regardless of the inclination of the initial portion of that prospect boring. Thus, as shown by FIG. 7, it is possible for that down-hole drill to establish a radius of curvature of 125 feet for the curved portion ofa prospect boring whether the initial portion of that prospect boring has an inclination of 8, 10 or 45.

By providing the bushing 160 and the flexible coupling 156, the present invention obviates the use of the steel wedges which must be used to enable a diamond drill to form a curved boring, and also obviates the use of the whipstocks which must be used to enable a rotary drill to form a curved boring. In doing so, the present invention saves the six-fold costs in time money which the use of such steel wedges or whipstocks entail. Actually, the bushing 160 and the flexible coupling 156 make it possible for the down-hole drill 154 to form curved prospect borings almost as quickly and economically as that down-hole drill can form straight borings. lmportantly, by using a down-hole drill, the present invention is able to provide radii of curvature for the prospect borings which are practical the smallest usable radius which a diamond drill or a rotary drill could provide for a curved boring being far too large to be practical for prospect borings. Specifically, the smallest usable radius which a diamond drill or a rotary drill could provide for a curved boring would be approximately 2,000 feet. Such a radius would require a curved prospect boring, which departed from a vein at an angle of 45 and which intersected an extension of that vein at an angle of 45, to have a total overall length of about 3,100 feet, to have its starting point and its point of intersection spaced apart along the vein extension a distance of about 2,800 feet, and to depart laterally a distance of about 600 feet from that vein extension. In contrast, with the I25 foot radius of curvature, made. possible by the use ofa down-hole drill, the total overall length of a curved prospect boring, which departs from a vein at an angle of about 45 and which intersects an extension of that vein at an angle of 45, is less than 200 feet, the distance between the starting point and the point of intersection of that curved prospect boring is less than feet, and the maximum lateral spacing between that curved prospect boring and that vein extension is only about 40 feet. If a curved prospect boring, which departed from a vein at an angle of sixty degrees and intersected the extension of that vein at that same angle, was drilled with the two thousand foot radius of curvature required by a diamond drill or a rotary drill, the overall length of that curved prospect boring would be about 4,200 feet and the distance between the starting point and the intersection would be about 3,450 feet. In contrast, with the 125 foot radius of curvature, made possible by the use of a down-hole drill, the total overall length of a similarly-inclined curved prospect boring would be only about 260 feet and the distance between the starting point and tne intersection would be only about two hundred and twenty feet. If a curved prospect boring, which departed from a vein at an angle of 30 and intersected the extension of that vein at that same angle, was drilled with the 2,000 foot radius of curvature required by a diamond drill or a rotary drill, the overall length of that curved prospect boring would be about 2,100 feet and the distance between the starting point and the intersection would be about 2,000 feet. In contrast, with the I25 foot radius of curvature, made possible by the use of a down-hole drill, the total overall length of a similarly-inclined curved prospect boring would be only about 130 feet. If a curved prospect boring, which departed from a vein at an angle of and intersected the extension of that vein at that same angle, was drilled with the two thousand foot radius of curvature required by a diamond drill or a rotary drill, the overall length of that curved prospect boring would be about 1,400 feet and the distance between the starting point and the intersection would be about 1,360 feet. In contrast, with the I foot radius of curvature, made possible by the use of a down-hole drill, the total overall length of a similarly-inclined curved prospect boring would be only about 87 feet and the distance between the starting point and the intersection would be only about 85 feet. The very short relative overall length of any curved prospect boring, which has a radius of cur-' vature of 125 feet, makes such curved prospect borings eminently practical and economical. Even if the radius of curvature of a curved prospect boring was increased to 600 feet, the total overall length of that curved prospect boring would be less than one-third of the overall length of a prospect boring which had the same angles of departure and intersection, but which had a radius of curvature of 2,000 feet. As a result, it should be apparent that the curved prospect borings disclosed by the present invention are far more practical and economical than any curved prospect borings of similar inclinations which could be formed with a diamond drill or a rotary drill.

When it becomes possible to purchase a down-hole drill that does not require rotation of the drill rod string therefor, it will be possible to form curved prospect borings with even smaller radii of curvature. Specifically, it should be possible, with such down-hole drills, to form curved prospect borings having radii of curvature as small as 60 feet; and such small radii of curvature would make it possible to reduce the overall lengths of such curved prospect borings even further.

In teaching how curved prospect borings, which have radii of curvature of 600 feet or less, can be drilled in a practical manner, the present invention makes it possible, for the first time, to drill curved prospect borings from points that are located wholly in the subsurface. Not only does the present invention make the drilling of such curved prospect borings possible from points that are located wholly in the subsurface, but it makes it pssible to drill such curved prospect borings quickly, inexpensively and with acceptably low levels of wear and abrasion on the drilling equipment.

When it becomes possible to purchase a down-hole drill that can drill curved prospect borings which lie in vertical planes and which have all portions of the lengths thereof upwardly directed or which have all portions of the lengths thereof downwardly directed, the area of use of the method taught by the present invention will be increased even further. Similarly, when it becomes possible to purchase a down-hole drill that can drill curved prospect borings which lie in horizontal planes or in planes that are inclined to the vertical, the area of use of the method taught by the present invention will be increased still further.

The system of sampling an ore body, which is provided by the present invention, is most useful in providing mining officials with information regarding the thickness and grade of ore which may be encountered if workings are extended. However, that system of sampling an ore body also is useful in determining the location, dimensions and grades of related or nearby ore bodies.

While various radii could be provided for the curved prospect borings of the present invention, those radii will preferably be between and 600 feet. Also, the preferred angle which is subtended between the final portion of a prospect boring and the projection of a vein will be between 20 and 60 encompassing a total reversal of direction of 40 to l20. While it would be possible to use a down-hole drill as large as four or more inches in diameter to drill a curved prospect boring, a smaller diameter down hole drill is more economical. Preferably, a down-hole drill in the range of three inches in diameter will be used; and such a drill would form a boring less than one inch larger in diameter'than its own diameter.

Whereas the drawing and accompanying description have shown and described a preferred embodiment of the present invention, it should be apparent to those skilled in the art that various changes may be made in the form of the invention without affecting the scope thereof.

What I claim is:

l. A method of sampling, in sub-surface mining operations, the amount of desired material in a proposed extension of a vein of said material including the steps of a. boring a hole from a point within a mine opening in said sub-surface adjacent said vein of said material,

boring said hole into the portion of said subsurface which is adjacent to and surrounds said vein of said material,

c. directing said holes so it generally extends in the direction of said proposed extension of said vein of said material but inclining the initial portion of said hole relative to the axis of said vein of said material so that initial portion of said hole departs from said axis of said vein of said material and from said vein of said material and enters said sub-surface,

d. extending said hole through said sub-surface and away from said axis of said vein of said material and away from said vein of said material until said hole reaches a point in said sub-surface which is wholly displaced from said vein of said material,

e. continuing to bore said bore so it generally extends in the direction of said proposed extension of said vein of said material but curving an intermediate portion of said hole insaid sub-surface until said hole is inclined back toward a planar projection of said proposed extension of said vein of said material,

f. extending said hole back through said sub-surface toward said planar projection of said proposed extension of said vein of said materail so that the concluding portion of said hole and said planar projection of said proposed extension of said vein of said material intersect,

g. boring said concluding portion of said hole so it in clines transversely of said planar projection of said proposed extension of said vein of said material,

h. extending said concluding portion of said hole through said planar projection of said proposed extension of said vein of said material,

i. whereby samples ofa portion of the material immediately adjacent said planar projection of said proposed extension of said vein of said material may be obtained,

j. said samples providing information regarding the location of, and regarding the transverse dimension of, said proposed extension of said vein of said material,

k. said hole being directed so it extends from said point within said mine opening in said sub-surface toward the proposed intersection of said hole with said planar projection of said proposed extension of said vein of said material but said hole having the major portion of the length thereof located wholly within said sub-surface, and thereby having the major portion of the length thereof wholly displaced from said vein of said material.

2. A method of sampling as claimed in claim 1 wherein a down-hole drill is used to bore said hole from said point within said mine opening to said proposed intersection of said hole with said planar projection of said proposed extension of said vein.

3. A method of sampling as claimed in claim 1 wherein said concluding portion of said hole is curved and has a radius of curvature of 600 feet or less.

4. A method of sampling as claimed in claim 1 wherein a down-hole drill is used to bore said hole from said point within said mine opening to said proposed intersection of said hole with said planar projection of said proposed extension of said vein, and wherein said concluding portion of said hole is curved and has a radius of curvature of 600 feet or less.

5. A method of sampling as claimed in claim 1 wherein a down-hole drill is used to bore said hole from said point within said mine opening to said proposed intersection of said hole and said planar projection of said proposed extension of said vein, wherein said concluding portion of said hole is curved and has a radius of curvature of 600 feet or less, and wherein a flexible coupling is interposed between said down-hole drill and the contiguous section of the drill rod string for said down-hole drill while said concluding portion of said hole is being formed.

6. A method of sampling as claimed in claim 1 wherein a down-hole drill is used to bore said hole from said point within said mine opening to said proposed intersection of said hole with said planar projection of said proposed extension of said vein, wherein said concluding portion of said hole is curved and has a radius of curvature of 600 feet or less, wherein a flexible coupling is interposed between said down-hole drill and the contiguous section of the drill rod string for said downhole drill while said concluding portion of said hole is being formed, and wherein a bushing is mounted on said contiguous section of said drill rod string to hold said flexible coupling and the rear end of said downhole drill above and out of engagement with the lower surface of said concluding portion of said hole.

7. A method of sampling, in sub-surface mining operations, the amount of desired material in a proposed extension of a vein of said material including the steps of a. boring a hole from a point within a mine opening in said sub-surface adjacent said vein of said material,

b. boring said hole into the portion of said subsurface which is adjacent to and surrounds said vein of said material,

c. directing said hole so it generally extends in the direction of said proposed extension of said vein of said material but inclining the initial portion of said hole at an angle relative to the axis of said vein of said material so said initial portion of said hole departs from said axis of said vein of said material and from said vein of said material at said angle and enters said subsurface,

d. curving said hole and extending said hole through said sub-surface and away from said axis of said vein of said material and away from said vein of said material until said hole reaches a point in said sub-surface which is wholly displaced from said vein of said material,

e. continuing to bore said hole so it generally extends in the direction of said proposed extension of said vein of said materaial but curving an intermediate portion of said hole in said sub-surface until said hole is inclined back toward a planar projection of said proposed extension of said vein of said material,

f. curving said hole and extending said hole back.

through said sub-surface toward said planar projection of said proposed extension of said vein of said material so that the concluding portion of said hole and said planar projection of said proposed exten sion of said vein of said material intersect at a second angle,

g. curving and boring said concluding portion of said hole so it inclines transversely of said planar projection of said proposed extension of said vein of said material,

h. extending said concluding portion of said hole through said planar projection of said proposed extension of said vein of said material,

i. whereby samples of a portion of the material immediately adjacent said planar projection of said proposed extension of said vein of said material may be obtained,

j. said samples providing information regarding the location of, and regarding the transverse dimension of, said proposed extension of said vein of said material,

k. said hole being directed so it extends from said point within said mine opening in said sub-surface toward the proposed intersection of said hole with said planar projection of said proposed extension of said vein of said material but said hole having the major portion of the length thereof located wholly within said sub-surface, and thereby having the major portion of the length thereof wholly displaced from said vein ofv said material,

. said hole being bored as an are which has a generally constant radius of curvature of 600 feet or less.

8. A method of sampling as claimed in claim 7 wherein a down-hole drill is used to bore said hole from said point within said mine opening to said proposed intersection of said hole with said planar projection of said proposed extension of said vein.

9. A method of sampling as claimed in claim 7 wherein a down-hole drill is used to bore said hole from said point within said mine opening to said proposed intersection of said hole with said planar projection of said proposed extension of said vein, and wherein a flexible coupling is interposed between said down-hole drill and the contiguous section of the drill rod string for said down-hole drill while said concluding portion of said hole is being formed.

10. A method of sampling, in sub-surface mining operations, the amount of desired material in a proposed extension ofa vein of said material including the steps of a. boring a hole from a point within a mine opening in said sub-surface adjacent said vein of said material,

b. boring said hole into the portion of said subsurface which is adjacent to and surrounds said vein of said material,

directing said hole so it generally extends in the direction of said proposed extension of said vein of said material but inclining the initial portion of said hole at an angle of from 20 to 60 relative to the axis of said vein of said material so said initial portion of said hole departs from said axis of said vein of said material and from said vein of said material at said angle and enters said sub-surface,

d. curving said hole and extending said hole through curving said hole and extending said hole back through said sub-surface toward said planar projection of said proposed extension of said vein of said material so the concluding portion of said hole and said planar projection of said proposed extension of said vein of said material intersect at an angle of from 20 to 60,

g. extending said concluding portion of said hole through said planar projection of said proposed extension of said vein of said material,

h. whereby samples of a portion of the material immediately adjacent said planar projection of said proposed extension of said vein of said material may be obtained.

. said samples providing information regarding the location of. and regarding the transverse dimension of, said proposed extension of said vein of said material.

. said hole being directed so it extends from said 6 point within said mine opening in said sub-surface toward the proposed intersection of said hole with said planar projection of said proposed extension of said vein of said material but said hole having the major portion of the length thereof located wholly within the sub-surface, and thereby having the major portion of the length thereof wholly displaced from said vein of said material,

k. said hole being bored as an are which has a generally constant radius of curvature of 600 feet or less.

11. A method of sampling, in sub-surface mining operations, the amount of desired material in a given area including the steps of:

a. boring a hole from a point within a mine opening in said sub-surface by means of a down-hole drill,

b. boring said hole into the portion of said subsurface which is adjacent to and surrounds said given area,

c. directing said hole so it generally extends in the direction of said given area but inclining the initial portion of said hole at an angle relative to a line extending from said point within said mine opening to said given area so said initial portion of said hole departs from said line at said angle and enters said sub-surface,

d. extending said hole through said sub-surface and away from said line until said hole reaches a point in said sub-surface which is wholly displaced from said line,

e. continuing to bore said hole so it generally extends in the direction of said given area but curving an intermediate portion of said hole in said subsurface until said hole is inclined toward said given area,

f. said intermediate portion of said hole being spaced from said point within said mine opening a distance less than 600 feet,

g. extending said hole back through said sub-surface toward said given area so the concluding portion of said hole enters said given area at an angle of from 20 to 60 relative to said line,

h. extending said concluding portion of said hole through said given area,

i. whereby samples of a portion of the material in said given area may be obtained,

j. said samples providing information regarding the operations, the amount of desired material in a given area including the steps of:

a. boring a hole from a point within a mine opening in said sub-surface by means of a down-hole drill,

b. boring said hole into the portion of said subsurface which is adjacent to and surrounds said given area,

c. directing said hole so it generally extends in the direction of said given area but inclining the initial portion of said hole at an angle relative to a line extending from said point within said mine opening to said given area so said initial portion of said hole departs from said line at said angle and enters said sub-surface,

d. extending said hole through said sub-surface and away from said line until said hole reaches a point said given area may be obtained,

. said samples providing information regarding the location of, and regarding the transverse dimension of, desired material in said given area,

j. said hole being directed so it extends from said point within said mine opening in said sub-surface toward said given area but said hole having the major portion of the length thereof located wholly within said sub-surface,

k. said concluding portion of said hole being curved and having a radius of curvature of 600 feet or less.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4013134 *May 20, 1974Mar 22, 1977The Richmond Manufacturing CompanyPortable earth boring machine with steering head
US4062412 *Jan 29, 1976Dec 13, 1977The United States Of America As Represented By The Secretary Of The InteriorFlexible shaft drilling system
US4186810 *Jul 5, 1977Feb 5, 1980John Macdonald & Company (Pneumatic Tools) LimitedFluid operated undercutter
US4415030 *Feb 9, 1981Nov 15, 1983Dresser Industries, Inc.Casing re-entry apparatus for use in inclined oil and gas boreholes
US7188671 *Oct 5, 2004Mar 13, 2007Saudi Arabian Oil CompanySystem, method, and apparatus for survey tool having roller knuckle joints for use in highly deviated horizontal wells
US20060070733 *Oct 5, 2004Apr 6, 2006Al-Zahrani Mufrih SSystem, method, and apparatus for survey tool having roller knuckle joints for use in highly deviated horizontal wells
WO1989004909A1 *Oct 31, 1988Jun 1, 1989Measurement Devices LimitedApparatus and method for measuring borehole deviation
Classifications
U.S. Classification175/61, 175/45
International ClassificationE21B47/022, E21B7/06, E21B47/02, E21B7/04
Cooperative ClassificationE21B7/04, E21B7/06, E21B47/02232
European ClassificationE21B7/04, E21B47/022P, E21B7/06