US3220494A

US3220494A - Raise drilling method and mechanism

Info

Publication number: US3220494A
Application number: US224756A
Authority: US
Inventors: Robert E Cannon; Douglas F Winberg; Dean K Mccurdy; Richard J Robbins
Original assignee: Robbins & Assoc James S
Current assignee: JAMES S ROBBINS AND ASSOCIATES Inc; Robbins & Assoc James S
Priority date: 1962-09-19
Filing date: 1962-09-19
Publication date: 1965-11-30
Anticipated expiration: 1982-11-30
Also published as: GB1009387A; JPS493881B1

Description

Nov. 30, 1965 R. E. cANNoN ETAL 3,220,494

RAISE DRILLING METHOD AND MECHANISM Filed Sept. 19, 1962 4 Sheets-Sheet l L ill O O O FIG.6

ROBERT E. CANNON DOUGLAS E WINBERG DEAN K. M CURDY RICHARD J. ROBBINS INVENTORS WWW! ATTORN s Nov. 30, 1965 R, E. CANNON ETAL. 3,220,494

RAISE DRILLING METHOD AND MECHANISM Filed Sept. 19. 1962 4 Sheets-Sheet 2 as O O O DEAN K. M CURDY RICHARD J. ROBBINS INV EN TORS ATTORNE s Nov. 30, 1965 R. E CANNON ETAL RAISE DRILLING METHOD AND MECHANISM 4 Sheets-Sheet 5 Filed Sept. 19, 1962 ROBERT E. CANNON DOUGLAS E WINBERG DEAN K. M CURDY RICHARD J. ROBB|NS INVENTORS BY 7mm MW ATTORN EYS Nov. 30, 1965 R. E. CANNON ETAL 3,220,494

I RAISE DRILLING METHOD AND MECHANISM Filed Sept. 19. 1962 4 Sheets-Sheet 4 1 FIGIO 2 240 i fmggfiw 7 0 UP I VALVE E'- a 1204 F A a I J l 244 DOWN/ 262 1 L I 242 11 1mm fi 25s FEEDTR 258 92m: A 3

- ROBERT E. CANNON QQ DOUGLAS F. WINBERG DEAN K. MCCURDY RICHARD J. ROBBINS IN VEN TORS Bywaivwwf ATTOR EYS United States Patent RAISE DRILLING METHOD AND MECHANHSM Robert E. Cannon, Hibbing, Minn, and Douglas F. Winberg, Bellevue, and Dean K. McCurdy and Richard J.

Robbins, Seattle, Wash, assignors to James S. Robbins and Associates, Inc., Seattle, Wash, a corporation of Washington Filed Sept. 19, 1962, Ser. No. 224,756 16 Claims. (Cl. 175--27) The present invention relates to the art of earth boring known as raise drilling, and more particularly relates to a raise drilling technique and equipment for practicing same wherein the raise hole boring operation proceeds by the drilling of a relatively small pilot hole on a downward pass, followed by enlargement of the hole to desired raise size by rotating and hydraulically raising a raise cutter head in a single upward pass.

A raise, as the term is used in the mining art, denotes a bore hole extending from a gallery or shaft at one level to a gallery or shaft at another level, with the raise hole running more or less vertically, often for a distance of one hundred yards or more. To be of practical size, raises are to be at least about 40 in diameter and are typically used in multi-level mining operations to provide ventilation, utility line access, water take-off and drainage conduits, rescue and escape shafts, and the like.

It is now common practice to dig raises from the bottom level upwardly by successive blasting and digging, which operation is inherently quite dangerous in that the personnel involved must work in the hole being formed and under the face of the hole being formed, with the supporting scaffolding oftentimes being partially demolished by the blasting involved, and with constant danger of blast debris falling on personnel while they are digging away debris and preparing for the next blast. There is also in use a raise drilling technique involving the drilling of a pilot hole from a lower gallery to an upper gallery, after which a larger bit is installed on the drill pipe and drawn back down the pilot hole, reaming the hole to larger size, the reaming operation often involving several successive passes of progressively larger reamers. In this technique, the reamed material is removed by gravity discharge through the relatively small area between the pilot hole wall and the drill stem.

Raise drilling involving the general proposition of boring a small hole during a downward pass, then enlarging the hole on an upward pass, is disclosed by German Patent No. 648,438 but this technique involve so-called hammer drilling during the upper pass and a non-torqued drill stem, so is necessarily low in drilling efficiency. Also, in such technique involving the hammer drilling of the large hole on an upward pass, it is customary to simply suspend the drill stem and hammer drill mechanism on a line or cable, which does not provide a sufficient anchor for tensioning the drill stem to the degree necessary for efiicient drilling, and of course does not anchor the drill stern support mechanism so that the drill stern can be torqued rotationally as is necessary for rotary drilling.

Also known, as in Aschacker US. Patent No. 2,837,324, is the technique for drilling between galleries with a pilot hole and an enlarged hole both formed during upward passes of cutter heads. This technique requires a winch means or the like in the upper gallery to pull the larger cutter head and has the further operational disadvantage that the entire drill stem used in drilling the pilot hole must be taken in before the enlarged hole drilling can begin. Separate guide means must also be maintained in the enlarged hole shaft below the larger cutter head, which impedes discharge of the debris down the hole.

3,229,494 Patented Nov. 30, 1965 Objects, features and advantages of the present invention involve the provision of a raise drilling method and mechanism wherein:

(a) the drilling operation involves rotating and hydraulically raising a raise cutter head along a pilot hole to form a raise hole between a lower level and an upper level in a single upward pass, the raise cutter head being guided only from above and solely by the pilot hole;

(b) the drilling rig is anchored to a base member which is in turn emplaced and anchored on the floor of the upper level shaft from which the raise is to be drilled, such base member providing positive anchoring of and footing for the drilling rig whether the drill angle is vertical or substantially off-vertical;

(c) the drilling rig anchoring base member is configured to be mechanically strong yet have a substantial degree of flexure so as to be self-accommodating to slight irregularities in the supporting ground when subject to the severe stresses incident to the raising and rotating of the raise cutter head;

(d) the base member equipped drill rig is precisely adjustable so as to drill at any desired angle from vertical to about 30 off-vertical;

(e) the base member is removable from the drilling rig so that while the rig is in use on one base member, another base member can be brought into position and emplaced at the next drill point desired and the drilling rig can then be simply transferred from the first base member to the second and the second drilling operation initiated without delay;

(f) a drilling rig which is versatile as to use of either a rotary or hammer type drill for drilling of the pilot hole and is also capable of rotating and rapidly raising a large cutter head so as to form a hole of desired raise size in a single upward pass;

(g) a drilling rig which is compact for underground use, yet capable of efficient rotary drilling of raise size bores, typical capabilities of the equipment in this regard including the generation of a cutter head lifting force of about tons and a rotational speed of about 35 rpm. on a cutter head 40" in diameter, with a drilling progress rate of as much as 30 or more per hour;

(h) an anchored and angularly adjustable drill rig having a main frame and four-columned guide structure on which a motor driven gear reducer for rotating a drill stem is hydraulically reciprocated during the drilling operation, the drive mechanism being especially designed for heavy duty use with the gear reducer being carried by a crosshead centered between guide columns and with the crosshead reciprocated by hydraulic power cylinders; and

(i) an anchored drill rig involving hydraulically powered reciprocation of a drill stem rotating assembly; wherein the hydraulic control system is designed to differentiate between low loading and high loading on the power cylinders and automatically provide fast drill stem transfer with low load and slow drill stem transfer with high load; wherein such fast transfer rate is several times faster than the slow transfer rate (e.g. by a ratio of about 12:1); wherein the hydraulic system is provided with control means for selectively counterbalancing the progressively increasing weight of the drill stem as the pilot hole drilling operation proceeds; wherein such system also includes means for selectively controlling the feed speed under high load; and wherein the system further comprises means for selectively controlling the maximum degree of drill stem lifting force.

These and other objects, features, advantages and characteristics of the raise drillingmethod and mechanism of the invention will be apparent from the following description of a typical and therefore non-limitive embodiment thereof, taken together with the accompanying illustrations, wherein like letters and numerals refer to like parts, and wherein:

FIG. 1 is a small scale view of the equipment in operation and forming a pilot hole on a downward pass, the separation between the upper level shaft and lower level shaft between which the raise is to run being fragmerited for simplicity of illustration;

FIG. 2 is a view like that of FIG. 1, showing a stage progress of the raise hole drilling operation, characteristic of the invention;

FIG. 3 is a view in side elevation of the drilling rig mounted on the crawler for transport, taken on a larger Scale and with certain parts broken away for clarity of illustration;

FIG. 4 is a front elevational view of the crawler and drilling rig as shown at FIG. 3;

FIG. 5 is a rear elevational view of the crawler and drilling rig as shown at FIG. 3 with certain parts broken away for clarity of illustration;

FIG. 6 is a detail plan view of the base member;

FIG. 7 is a View in side elevation of the equipment with the drilling rig tilted uprightly and mounted on the base member, the vertical operative position thereof being shown in solid line, and a typical off-vertical operative position thereof being fragmentarily shown in broken line;

FIG. 8 is a front elevational view of the drilling rig as shown at FIG. 7;

FIG. 9 is a plan view of the gear reducer and part of the drive motor therefor, with certain parts thereof broken away;

FIG. 10 is a cross sectional view of the gear reducer shown at FIG 9, taken substantially along line lO-1O thereof; and

FIG. 11 is a somewhat simplified schematic presentation of the hydraulic control system for the drilling power cylinders and associated erection cylinders.

As shown in FIGS. 1-10, the raise drilling mechanism in general comprises a crawler or tractor C, a base member or footing B, and a rotary drilling rig D. Crawler C is suitably of a low-silhouette type in general usage for mining and other transport purposes, having power driven endless tracks 20. In adapting such a crawler for use in conjunction with the drilling rig of the present invention, the between track frame 22 (FIG. 4) is provided with forwardly placed pivot plates 24 to which the drilling rig D is pinned during transport, as well as a laterally placed pair of erection cylinders 26 rearwardly anchored to eye pads 28 at the rear of the crawler C. Crawler C also suitably carries portions of the hydraulic and electrical systems associated with the rig, specifically electrical control panel 30, hydraulic pump drive motor 32, low pressure pump 34, high pressure pump 36 (FIG. 5 and hydraulic fluid reservoir 38.

Removable base member B is preferably of generally U-shaped configuration, as best shown at FIG 6, with a work access opening 40 between forwardly extending

feet

42, 44, the

feet

42, 44 being joined rearwardly so as to provide an integral base structure. As shown in FIG. 7, for example, the bottom 46 of the base member B is essentially flat (also note FIG. 8), and the

feet

42, 44 respectively comprise pairs of upstanding

parallel webs

48 and 50. The rear portion of the base member B also comprises a strengthening box 52 to provide adequate structural strength to the base member without undue weight. In use, base member B is emplaced with the work opening 40 at the desired drill point, and is anchored in place as by rock bolts 53 (FIGS. 1 and 2) placed in the supporting ground through edge placed holes in the base member B, certain of which holes are indicated at 54 (FIG. 6).

Feet

42, 44 and the U-shaped configuration of the base member B, in the embodiment illustrated, permit a substantial degree of flexure of the base member B to accommodate slight irregularities in the supporting ground 4 (FIGS. 1 and 2) under the severe load placed thereon by operation of the drilling rig. In a typical installation, the base member B is cast of medium carbon steel and weighs about 3300 lbs.

The main frame of the drilling rig D releasably and adjustably connects to and is supported by the base member B, and comprises a series of

parallel plates

60, 62, 64, 66, the

inboard plates

62, 64 being joined by a work table 68 and a stiffener plate 70, and the respective side pairs of

plates

60, 62 and 64, 66 also being joined by suitably placed stiffener plates, two of which are shown at 72, 74.

The rearward extremities of

inboard plates

62, 64 are provided with

respective holes

76, 78, through which

respective pins

80, 82 are placed in pinning the drilling rig to the pivot plates 24 of the crawler C when the drilling rig is in transport position. Said

inboard plates

62, 64 also extend upwardly in the rear portions thereof and are pinned to the ends of the rods of erection cylinders 26, as shown.

When the drilling rig D is emplaced on the base member B, as in FIGS. 7 and 8, the

main frame plates

60, 62 and 64, 66 are pinned to the rear portions of respective

base member webs

48 and 50 by

pins

84, 86 and the forward end of the drilling rig D is angularly adjustable with respect to the base member B by means of a pair of threaded

turnbuckle assemblies

88, 90, each of which is adjustable between respective

lower sleeves

92, 94 and respective

upper sleeves

96, 98, the said

lower sleeves

92, 94 being pinned to the forward portions of

webs

48, 50, by

respective pins

100, 102, and the respective

upper sleeves

96, 98 being pinned by

respective pins

104, 106 to an alined pair of the respective series of adjustment holes 108, 110 arranged vertically along the forward edges of the

respective plates

60, 62 and 64, 66. As will be evident, angular adjustment of the rig drill line DL with respect to the plane of the bottom 46 of the base member B occurs about the pivot axis provided by

pins

84, 86, with coarse adjustment being effected by selective placement of

pins

104, 106 in the desired pairs of adjustment holes 108, 110, and with fine angular adjustment being effected by variation in the length of the

turnbuckle assemblies

88, 90.

In operation of the drilling rig, the sectioned drill stem S is rotated and carried by an end threaded connector pin 116. Said connector pin 116 is of a type conventional per se with a flat sided collar 118 to which a suitable wrench (not shown) is applied during coupling and uncoupling of the uppermost drill stem section. The sections of drill stem S are interconnected with like connector pins and each end of each drill stem section is provided with wrench receiving slots, such as indicated in FIG. 8 at 120. As also shown in the fragmentary view thereof at FIG. 8, each section of drill stem S is tubular, and relatively thickwalled for strength.

The said threaded connector pin 116 threads to the output shaft of a motor driven gear reducer indicated generally at 122, having a reduction gear train (cf. FIG. 10) driven by motor 124. The rotational axis of connector pin 116 is coincident with the opening 69 in work table 68 and with the drill line DL.

The gear reducer housing 126 has four guide sleeves or

bosses

128, 130, 132, 134 (note FIG. 9) extending outwardly therefrom. Said guide

sleeves

128, 130, 132, 134 surround respective mast-

like guide columns

136, 138, 140, 142. The upper extremities of said guide columns are pinned to a top frame 144, and the

guide columns

136, 140 at one side of the driver assembly are pinned in respective

column socket members

146, 148 welded between

main frame plates

60, 62, while the

opposite side columns

136, 142 are pinned in respective

column socket members

150, 152 welded between

main frame plates

64, 66. Each of the

guide sleeves

128, 130, 132, 134 is movable reciprocably on the

respective columns

136, 138, 140, 142, with suitable bushings and seals provided therebetween, such as respectively indicated at 154 and 156 in the broken away portion of guide sleeve in FIG. 3.

Rectilinear movement of the gear reducer 122 to raise and lower the sectioned drill stem S and cutterhead is accomplished by a parallel pair of

hydraulic cylinder assemblies

158, 150, also termable main cylinders or power cylinders. The cylinder ends of said

hydraulic cylinder assemblies

158, 160 are pivotally anchored to the main frame by

respective pins

162, 164 placed near bottom center of the respective

main frame plates

60, 62 and 64, 66, the common axis of said

pins

162, 164 intersecting the axis of rotation of the drill stem connector pin 116.

The thrust lines TL of the

hydraulic cylinder assemblies

158, 160 lie in a common plane with and are equidistant from the drill line DL, and the

guide columns

136, 138, 140, 142 are also all equidistant from the drill line DL, with each thrust line TL also equispaced between each respective side pair of

guide sleeves

128, 132 and 130, 134. This arrangement of the parallel hydraulic cylinder assemblies and guide columns in relation to the drill line provides ideal distribution and balancing of the thrust stresses generated during the raise hole boring operation. The

respective piston rods

166, 168 of

hydraulic cylinder assemblies

158, 160 are pinned to a crosshead 170 bolted to

opposed ears

172, 174 extending laterally from the gear reducer housing 126. The arrangement of the crosshead 170 and the

ears

172, 174 on the housing 126 is such, as shown, that the thrust plane in which the drill line LD and thrust lines TL lie bisects the crosshead and the connection thereof to the gear reducer housing.

As shown in FIG. 10, the output shaft of the gear reducer 122 is tubular so that air, water or other drilling fluid can be delivered through the tubular drill stem to the cutterhead during the downward pilot hole drilling, if desired. Suitable delivery of the air or fluid to the drill stem is effected through a swivel line connector 176 (FIG. 8).

The throw of the

hydraulic cylinders

158, 160 is sufiicient to reciprocate the gear reducer on the guide columns a distance slightly greater than the length of the sections making up the drill stern S. To provide a relatively small height requirement for the drilling rig in operation, relatively short drill stem sections are employed. With 42" drill stem sections, for example, guide

columns

136, 138, 140, 142 are suitably of a length to permit movement of the gear reducer 122 a distance of about 51". The uppermost extent of travel of the gear reducer 122 involves movement of the

guide sleeves

128, 130, 132, 134 next to the top frame 144, in which position the uppermost portions of the

rods

166, 168 and crosshead 170, and also the motor 124, emerge above the top frame 144. Such position of the motor 124 is shown in broken line as part of the broken line off-vertical showing of the drilling rig in FIG. '7.

As shown in the developed cross sections view of FIG. 10, the gear reducer comprises a housing 126, with the motor 124 mounted on a motor mount 178 at one side thereof. By way of example, said motor 124 in a typical installation is a 60 H.P., reversible electric motor, operating at synchronous speeds of 3600 rpm. and 1800 rpm, and is energized and controlled in a manner known per se. Th shaft 124' of motor 124 is directly coupled to a high speed pinion 180 which in turn meshes with and drives a high speed gear 182 splined to the intermediate pinion shaft 184, in the opposite end of which the teeth of intermediate pinion gear 186 are cut. The intermediate pinion 186 on shaft 184 meshes in turn with the intermediate gear 188 splined to the low speed pinion shaft 190, at the opposite end of which the teeth of low speed pinion gear 192 are provided. The low speed pinion 192 on shaft 190 meshes in turn with the low speed gear 194 which in turn is splined to output shaft 196. Output shaft 196 is threaded at the lower end 196' thereof to receive the connector pin 116. As shown at FIG. 10, the said output shaft 106 is provided with an inner bore 198 which serves as a conduit for the air, water or drilling fluid fed thereto from swivel connector 176, delivering 6 same to the tubular drill stem S. Typical seals, bearing arrangements and bearing mounts in the gear reducer 122 are also shown at FIG. 10.

The gear reducer 122 illustrated at FIG. 10 is of extra heavy duty design to withstand the severe strains incident to rotation of a relatively large cutterhead used for drilling the raise hole, and is characterized by a gear reduction ratio between the motor shaft 124' and the output shaft 1% of :1, for example. As will be readily apparent, however, the specific gear reducer and drive motor layout can be widely varied as a matter of design choice. By way of further example in this respect, it will be understood that the motive means for rotating the drill stem can include other types of prime movers, such as a low speed, high torque reversible hydraulic motor, in which event the reduction gear train can be considerably simpli fied.

The hydraulic control system for the raise drilling equipment is shown at FIG. 11. The system includes two separate and independent hydraulic circuits, one leading from the fluid reservoir 38 to

power cylinder assemblies

158, 160, and the other leading from said fluid reservoir 38 to the erection cylinder assemblies 26. Low pressure high volume pump 34 and high pressure low volume pump 36 are both driven by motor 32 and both in the power cylinder circuit during drilling. Only the high pressure pump 36 is in the erection cylinder circuit. The output volume of low pressure pump 34 is about twelve times the output volume of high pressure pump 36. A three-way Selector Valve 200, so designated in FIG. 11, serves to,select either the power circuit or set-up circuit to receive the output from high pressure pump 36.

In the power cylinder circuit the low pressure pump 34 and the high pressure pump 36 are located in parallel and when both are in operation their respective outflows join at junction 202 before flowing through a multi-ported pilot valve 204 to one side or the other of

cylinder assemblies

158, 160.

The low pressure branch of the power cylinder circuit includes a manual off-on valve 206, the low pressure pump 34, and a pump disabling valve 208, all of which are connected in series flow relationship with pump inlet line 210. The pump disabling valve 208 consists of a self-contained check valve 212, and a normally closed return valve 214. A pressure take-off line 216 connects an expandable chamber on top of return valve 214 with fluid line 210 at a point between the check valve 212 and junction 202.

The high pressure branch of the power cylinder actuating circuit includes a manual off-on valve 218, the high pressure pump 36, a fixed setting pressure relief valve 220, an adjustable three-way valve 200 (acting as the Selector Valve and so designated in FIG. 11), a variable setting pressure relief valve (acting as the Force Control Valve and so designated in FIG. 11), and a manually operated Feed Control Valve 224 (also so designated in FIG. 11), all of which are connected in series flow arrangement with pump inlet line 228. The Feed Control Valve 224 is provided with an automatic flow regulator 226 of a conventional type.

At junction 202

lines

210 and 228 combine into a single flow line 230 leading to one port of the multiported Direction Control Valve 204. Line 232 leading from valve 204 returns to fluid reservoir 38, line 234 leads to the respective piston sides of

cylinder assemblies

158, 160, and line 236 leads to the respective rod sides thereof.

Line 234 includes a counterbalancing valve 238 comprising a self-contained check valve 240 and a normallyclosed return valve 242. Line 236 includes a transfer valve 244 comprising a self-contained check valve 246 and a normally-closed return valve 248. A pressure takeoff line 250 connects an expandable chamber on top of return valve 248 with line 234 at a point between check valve 240 and the piston sides of the

power cylinder assemblies

158, 160. Similarly, a second pressure take-off line 252 connects an expandable chamber on top of return valve 242 with line 236 at a point between check valve 246 and the rod sides of the

power cylinder assemblies

158, 160. A recirculating line 254 is provided to connect line 236 with line 230, and a check valve 256 is located in the recirculating line and seated to allow flow from line 236 to line 230, but not reversely. The return circuit through normally closed, over pressure opening return valve 244 is what may be termed a diflerential circuit, providing high speed feed under low load, and low speed under high load. This permits rapid movement of the raise cutterhead until engagement thereof with the work face, then automatically shifts the feed speed to a low rate when the work loads the cutterhead. The pressure at which the differential circuit operates is manually adjustable, as indicated at 248'.

During drilling, the operation of the power cylinder assemblies is as follows. Assuming that the several valves are in the positions shown in the drawing, and assuming further that the respective pistons of the power cylinder assemblies are in their lowermost positions,

inlet valves

206 and 218 are opened and the motor 32 is energized. The hydraulic fluid is pumped by the low pressure pump 34 from reservoir 38 through open valve 206, check valve 212, line 230, port 258 of valve 204, and into return line 232 leading back to the reservoir 38. Fluid is pumped by the high pressure pump 36 through Force Control Valve 222 back into the reservoir 38. Force Control Valve 222 is adjusted to desired maximum operating pressure, say about 500l800 p.s.i., depending upon the nature 'of the rock being drilled. Valve 222 is set to open at a lower pressure than fixed relief valve 220, which can open at about 2,000 p.s.i., for example, and valve 222 opens during this phase of the operation because Feed Control Valve 224 is closed.

When it is desired to raise the drill stem S into working position during raise hole drilling, valve 204 is rotated 45 to the right putting valve port 260 in communication with

lines

230 and 234, and valve port 262 in communication with lines 236 and 232. Feed Control Valve 224 is then opened a desired amount, allowing the high pressure fluid to flow through said valve 224 and combine with the delivery of the low pressure pump in line 230, causing Force Control Valve 222 to close. The pumped fluid flows through line 230, port 260, and line 234, urging check valve 240 open, and then flows into the piston sides of

cylinder assemblies

158, 160, causing the pistons thereof to move upwardly.

As indicated, pump 34 is a high speed low pressure pump and pump 36 is a low speed high pressure pump. When there is no working load on the drill stem the greater part of the flow in line 230 is from the low pressure pump 34, but when the working load is encountered by

cylinder assemblies

158, 160, the low pressure fluid is not used and the low pressure pump is unloaded, since a portion of the high pressure fluid in line 230 flows through line 216 into the expandable chamber above low low pressure return valve 214 and urges said valve 214 open, returning the low pressure pump output to the reservoir 38. Check valve 212 prevents flow of the high pressure fluid into the low pressure pump 34.

During movement of the drill stem without working load, the upper working chambers of the cylinders are in communication with the lower working chambers thereof, thereby subjecting the upper and lower working chambers to substantially the same pressure. The ef" fective area of the pistons tending to cause upward movement is then equal to the cross sectional area of the piston rods, and such area is relatively small resulting in a relatively small but suflicient thrust being developed. The fluid above the pistons cannot flow into line 236 because return valve 248 is biased closed and check valve 246 seats in the direction of flow. Therefore, the fluid flows through line 254, unseats check valve 256, and combines with the pump outputs thereby equalizing the pressure on both sides of the pistons.

When the raise cutterhead contacts the work the pressure in line 234 is increased and a portion of the fluid in such line flows through pressure take-01f line 250 into the expandable chamber above return valve 248, forcing said valve 248 into its open position. The path through valve 248 is then the path of least resistance and the path through which the fluid from the upper working chamber flows. From line 236 the fluid flows through valve port 262 into return line 232 leading back into the reservoir. When valve 248 is open, the upper working chambers are at substantially atmospheric pressure because the reservoir pressure is substantially atmospheric. The entire area of the undersides of the pistons thus becomes the eflective area, and a relatively large moving force is developed while the cutterhead is working.

As can readily be seen, movement of the pistons can be stopped at any time by returning Direction Control Valve 204 to its neutral position, and the drill stem and cutterhead are in such case retained in the position which they then occupy. The seating of check valve 240 and normally closed return valve 242 prevent the fluid from draining from the piston sides of the cylinder assemblies into line 234 and, in addition, line 234 is blocked off at Feed Control Valve 204.

When it is desired to lower the pistons, Feed Control Valve 204 is rotated 45 to the left of the position shown, putting line 236 in communication with line 230 through valve port 262 and line 234 in communication with return line 232 through valve port 260. It will be noted that at this stage the pistons are at least momentarily still locked in position because flow through valves 240 and 242 is prevented. Then, as the fluid pressure in line 236 increases, check valve 246 opens and the fluid enters the rod sides of the

cylinder assemblies

158, 160 and exerts a pressure tending to force the pistons thereof downwardly. Some of the fluid from line 236 flows through pressure take-off line 252 and moves return valve 242 to its open position. When this occurs the fluid below the pistons drains through line 234, port 260 and line 232 back into the reservoir.

counterbalance valve 242 also counterbalances the weight of the drill stem and cutterhead during the pilot hole drilling operation. Valve 242 remains closed and prevents flow of fluid out of the lower chambers of

assemblies

158, 160 so long as there is no further fluid delivery into the upper chamber. In the static condition the lower chamber pressure is considerably greater than the upper chamber pressure, i.e. a back pressure condition exists. This back pressure is not relieved until Direction Control Valve 204 lets fluid into the upper chamber and there is suflicient pressure build-up therein to cause valve 242 to open. Valve 242 and its .control responsive to upper chamber pressure through valve 252 provide a continuing back pressure condition yet permit the pistons to be selectively pumped" down against the back pressure during the progress of the pilot hole boring operation. Manual adjustment means 242' of valve 242 regulates the pressure differential necessary across the pistons to move the pistons downwardly. By this means the progressively increasing drill stem weight can be compensated for so that the effective working force at the pilot hole cuterhead can be maintained the same regardless of the length of the drill stem.

Turning now to the drilling rig set-up circuit, this circult starting at Selector Valve 200 includes a flow line 264, a Set-Up Control Valve 266 (so designated in FIG. 11), the working chambers of the erection cylinder assemblies 26, and a normally-closed return valve 270. When Set- Up Control Valve 200 is turned counterclockwise from the position shown in FIG. 11, the fluid discharging from the high pressure pump 36 enters line 264, flows through valve port 272 in the valve 266, and returns to reservoir 38 through return line 274. When it is desired to extend the cylinder assemblies to move the drilling rig D from transport to operating position, Set-Up Control Valve 266 is rotated 45 to the left of the position shown,

thereby communicating line 264 with line 276 through valve port 278, and communicating line 280 with line 282 through valve port 284. The fluid flows from line 264 into line 276 leading to the piston sides of cylinder assemblies 26 and tends to extend the assemblies 26. Momen tarily, at least, the pistons of assemblies 26 do not move because line 280 leading from the chambers above said pistons is blocked by normally-closed valve 270. Line 264 communicates with the expansible chamber at the top of return valve 270 by means of a pressure take-off line 286, and when the pressure in line 264 reaches a predetermined value (e.g. 1,200 p.s.i.), the fluid forces valve 270 to an open position permitting the fluid above the pistons of assemblies 26 to drain through line 280 to the reservoir 38. The assemblies 26 can be locked in any set position by merely returning Set-Up Control Valve 266 to its neutral position.

When retraction of assemblies 26 is desired, valve 266 is rotated 45 clockwise of its neutral position so that line 282 communicates wtih line 276 through valve port 278 and line 264 communicates with line 280 through valve port 284. The pumped fluid then flows through valve port 284 into line 280 and to the rod sides of assemblies 26 causing retraction thereof.

The manner of operation enabled by the mechanism of the present invention is discussed below primarily with reference to the operating views presented by FIGS. 1 and 2 and the hydraulic system schematic presented by FIG. 11. Assuming that the equipment is on location in an upper level gallery or shaft UL, along with a suitable supply of drill stem S sections and a pilot hole cutter head PC, the base member B is preliminarily positioned on the floor of the upper level shaft UL with the desired drill point exposed in work opening 40 of the base member B. This layout, and a determination of the particular drill line DL that the drilling rig is to be placed at on the base member B, is usually determined by a mine surveyor.

With the base member B in proper location, rock bolts are placed in holes 54 of the base member, and the drilling rig is transported by crawler C (cf. FIG. 3) into position at the rear edge of the base member. Selector Valve 200 is placed in position to deliver hydraulic fluid to the rig set-up circuit and the motor 32 is energized..-

Set-Up Control Valve 266 is then moved to its up position and the drilling rig D is tilted from its horizontal position until a tilt angle is reached where

pins

84, 86 can be placed through the

base member webs

48, 50 and

main frame plates

60, 62 and 64, 66, as shown at FIG. 7. After placement of said pins 84, 86, erection cylinder assemblies 26 are extended a little more to relieve the weight on

pins

80, 82, which pins are then withdrawn from the pivot plates 24 on the crawler C. Then, assemblies 26 are extended further by jogging of Set-Up Control Valve 266 until the drill rig D is positioned at approximately the desired drill angle with respect to the floor of the upper level UL.

Turnbuckle assemblies

88, 90 are then installed between the base member B and the main frame, with the turnbuckle

upper pins

104, 106 being placed in an appropriate pair of adjustment holes 108, 110. Fine adjustment of the drill rig angle to place the drill line DL at precisely the desired drill angle is then accomplished by selective rotation of the respective adjustment sleeves of the turnbuckle assemblies.

With the base member B and drill rig D thus in place for the drilling operation, Selector Valve 200 is shifted clockwise to its operating position for drilling, the Direction Control Valve 204 is operated to raise the gear reducer 122 and its connector pin 116, and the pilot hole cutterhead PC is installed on the pin 116. For the pilot hole drilling operation, either a pilot hole cutterhead PC or a rotated cone type of the air hammer drill type can be employed, as desired. The pilot hole cutterhead PC is of suitable size to leave the pilot hole PH just slightly larger than the drill stem S. Thus, with a drill 10 stem 5 /2" in diameter, the cutterhead PC can be about 6% in diameter, for example.

To initiate the pilot hole drilling operation, the gear reducer drive motor 124 is energized, the Direction Control Valve 204 is moved to its down position, and the air, water or other drilling fluid employed in the drilling operation is delivered to swivel connector 176 (FIG. 8). When the drilling has proceeded to the point where the guide sleeves 128434 have reached about their lowermost extent of travel on guide columns 136-142, the Direction Control Valve 204 is placed in neutral position, motor 124 is de-energized, the air or other fluid supply is cut oil, the cutterhead PC is uncoupled from the connector pin and supported on the work table 68 by wrench means (not shown), and the gear reducer is returned to about its uppermost position by means of Direction Control Valve 204. A section of drill stem S is then coupled between the pin 116 and the cutterhead PC, and the drilling resumed by movement of the Direction Control Valve 204 to its down position. The pilot hole drilling operation thus progresses with successively introduced drill stem sections and downward work strokes until the pilot hole is formed through the mineral formation M from the upper level shaft UL to the lower level shaft LL. A state of progress of the pilot hole drilling operation shortly before emergence of the pilot hole cutterhead PC into the lower level shaft LL is shown at FIG. 1.

With the pilot hole formed and the sectioned drill stem S laid through the pilot hole from the upper level UL to the lower level LL, the pilot hole cutterhead PC is removed from the drill stem S and a raise cutterhead RC of suitable size (e.g. 40 in diameter) is connected to the drill stem. The raise hole drilling operation is then commenced by rotation of the drill stem S through energization of motor 124 and by the

hydraulic cylinder assemblies

158, 160 raising the drill stem S and raise hole cutterhead RC in a single upward pass, and the raise hole boring operation proceeds with cyclic performance of a working lift of the drill stem and raise cutterhead, an uncoupling and removal of the drill stem upper section, a lowering of the gear reducer 122, a recoupling of the drill stem to the gear reducer, and a further raising of the drill stern and cutterhead, and so on until the raise hole RH is formed between the lower level shaft LL and upper level shaft UL. A typical state of progress of the boring of the raise hole upwardly in a single pass by rotating and hydraulically lifting the sectioned drill stem S and raise cutterhead R is shown at FIG. 2.

While the drilling operation is proceeding at one drill location, the placement of a second base member B at the next drilling location can be accomplished, so that the second base member is available to receive the drilling rig D immediately upon conclusion of the first drilling operation. The transfer of the drilling rig to the second base member is accomplished simply by uncoupling the turnbuckle assemblies 88, and retracting the erection cylinder assemblies 26 until the

pins

80, 82 can be placed in the

holes

76, 78 in the inboard

main frame plates

62, 64 and the pivot plates 24 of the crawler C. Pins 84, 86 are then removed from the base member B, and the crawler C is backed off from the first base member B and driven to the second base member. The mounting of the drilling rig D on the second base member at the particular drill angle desired is accomplished in the same manner as the mounting procedure with respect to the first base member. As will be apparent, at the conclusion of drilling the tilting of the drilling rig back to transport position on the crawler involves like manipulation except that the cylinder assemblies 26 are fully retracted to place the drilling rig in a horizontal position for transport (again note FIG. 3).

From the foregoing, various further adaptations, component arrangements and modes of utilization of the drilling mechanism and technique characteristic of the invention will be apparent to those skilled in the art to which the invention is addressed, within the scope of the following claims.

What is claimed is:

1. The method of drilling a large diameter raise hole to run between an upper level and a shaft or the like at a lower level underground, comprising: rigidly emplacing a base member in fixed position on the floor of the upper level at the desired drill point and in substantially surrounding relation to the axis of the hole to be formed; mounting a rotary drilling rig on said base member to place the drill line of the rig at the desired drill angle; forming a pilot hole from the upper level to the lower level in a downward pass with a small cutterhead mounted at the end of a sectioned drill stem arranged concentrically with the hole and fed progressively downwardly by the drilling rig; removing the small cutterhead from the sectioned drill stem at the lower level when the pilot hole has been drilled; placing a cutterhead of raise hole forming size on the end of the sectioned drill stem at the lower level; and simultaneously rotating and hydraulically lifting the drill stem and raise forming cutterhead with respect to said base member to form a large diameter raise hole in a single upward pass.

2. The method of drilling a large diameter raise hole to run between an upper level and a shaft or the like at a lower level underground, comprising: rigidly emplacing a base member in fixed position on the floor of the upper level at the desired drill point and in substantially surrounding relation to the axis of the hole to be formed; mounting a rotary drilling rig on said base member; adjusting the relative angle between said drilling rig and said base member to place the drill line of the rig at the desired drill angle; forming a pilot hole from the upper level to the lower level in a downward pass with a small cutterhead mounted at the end of a sectioned drill stem arranged concentrically with the hole and fed progressively downwardly by the drilling rig; removing the small cutterhead from the sectioned drill stem at the lower level when the pilot hole has been drilled; placing a cutterhead of raise hole forming size on the end of the sectioned drill stem at lower level; and simultaneously rotating and hydraulically lifting the drill stem and raise forming cutterhead with respect to said base member to form a large diameter raise hole in a single upward pass.

3. The method of drilling a raise hole to run between an upper level and a shaft or the like at a lower level underground, comprising: rigidly emplacing a base member on the floor of the upper level at the desired drill point and in substantially surrounding relation to the axis of the hole to be formed; arranging a rotary drilling rig on said base member at a desired relative angle between said drilling rig and said base member to place the drill line of the rig at the desired drill angle; forming a pilot hole from the upper level to the lower level in a downward pass with a small cutterhead mounted at the end of a sectioned drill stem fed progressively downwardly by the drilling rig; removing the small cutterhead from the sectioned drill stem at the lower level when the pilot hole has been drilled; placing a cutterhead of raise hole forming size on the end of the sectioned drill stem at the lower level; and progressively forming the raise hole in a single upward pass by rotating and hydraulically lifting the sectioned drill stem and raise hole forming cutterhead, the lifting action being characterized by an increase in lifting force and a reduction in feed rate responsive to loading on the raise hole forming cutterhead in excess of a predetermined loading.

4. The method of drilling a raise hole to run between an upper level and a shaft or the like at lower level underground, comprising: rigidly emplacing a base member on the floor of the upper level in substantially surrounding relation to the axis of the hole to be formed; mounting a rotary drilling rig on said base member at the desired drill angle; drilling a pilot hole with said drilling rig so that the pilot hole extends from the upper level to the lower level, such pilot hole being drilled with a small cutterhead mounted at the end of a sectioned drill stem arranged concentric with the hole and urged downwardly hydraulically by the drilling rig; counterbalancing the progressively increasing weight of the drill stem so as to maintain the loading of the small cutterhead against the work face throughout the progress of the pilot hole drilling; removing the small cutterhead from the sectioned drill stem at the lower level when the pilot hole has been drilled; placing a cutterhead of raise hole forming size on the end of the sectioned drill stem at the lower level; and progressively forming a raise hole in a single upward pass by rotating and hydraulically lifting the sectioned drill stem and raise hole forming cutterhead with respect to said base member.

5.'A raise drilling machine for underground drilling of a raise hole between an upper level and a shaft or the like at a lower level, said machine comprising:

(a) a flat-bottomed base member rigidly anchored on the floor of the upper level in substantially surrounding relation to the axis of the raise hole to be formed;

(-b) a rotary drilling rig including:

(i) a supporting frame rigidly mounted to said base member and angularly adjustable with respect thereto to orient the drilling rig with respect to the desired drill line;

(ii) upstanding guide columns on said supporting frame;

(iii) a drill rotator assembly reciprocably movable along said guide columns, including power driving means and a gear reducer having a rotated output shaft; and

(iiii) double-acting hydraulic cylinder means for raising and lowering said drill rotator assembly along said guide columns;

(c) a sectioned drill stem coupled to said output shaft;

(d) a small diameter cutter element mountable concentrically at the end of said sectioned drill stem from said upper level to said lower level; and

(e) a large diameter cutterhead of raise hole forming size mountable concentrically at the end of said sectioned drill stem at said lower level, upon removal of said small diameter cutter element therefrom, to form a raise hole along said pilot hole during a single upward pass of the drill stem.

6. A raise drilling machine according to claim 5, wherein said double-acting hydraulic cylinder means comprises two heavy duty hydraulic cylinder assemblies with the cylinders thereof anchored to said supporting frame and with the piston rods thereof joined tosaid drill stern rotator assembly, the respective thrust lines of said cylinder assemblies being parallel'and equispaced from the drill line of the drilling rig at opposite sides thereof.

7. Raise drilling mechanism for downwardly drilling a pilot hole from an upper level to a lower level underground and for drilling a raise hole along the path of the pilot hole in a single upward pass, said mechanism comprising: a base member configured to substantially surround the axis of the hole to be formed; means rigidly anchoring said base member to the ground at the upper level; and a drilling. rig rigidly mounted on said base member and adjustable angularly thereof so as to establish the drill line of the rig at a desired drill angle with respect to the floor of the upper level, said drilling rig comprising a powered drill stem rotator assembly, hydraulically powered means for reciprocating said drill stem rotating assembly along said drill line, and a plurality of upstanding guide columns arranged with the longitudinal axes thereof parallel to said drill line, the said drill stem rotator assembly comprising guide sleeves slidable on said guide columns, and the said hydraulically powered means for reciprocating said drill stem rotator assembly comprising a plurality of double-acting hydraulic cylinder assemblies arranged with the respective thrust lines thereof parallel to said drill line, all of said guide 13 columns being equispaced from said drill line, and the said hydraulic cylinder assembly thrust lines being equispaced from said drill line.

8. The raise drilling mechanism according to claim 7, further comprising erosshead connection means between said drill stem rotator assembly and said hydraulic cylinder assemblies, the said drill line and thrust lines lying in a thrust plane which bisects said crosshead connection means.

9. The raise drilling mechanism according to claim 7, wherein the angular adjustment of the drilling rig with respect to the base member is accomplished by turnbuckle assemblies interconnecting one side of said base member with one side of said drilling rig.

10. Raise drilling mechanism according to claim 11, wherein said base member comprises pairs of upstanding parallel webs, the said turnbuckle assemblies being connectible between the said base member webs and the said main frame parallel plates.

11. Raise drilling mechanism according to claim 9, wherein said drilling rig comprises a main frame having pairs of inboard and outboard parallel plates, each such pairs of plates having a series of pairs of adjustment holes to which the said turnbuckle assemblies are connectible for coarse adjustment of the angle of the drill line with respect to said base member.

12. Raise drilling mechanism according to claim 8, wherein said base member is essentially flat bottomed and of generally U-shaped configuration in plan, being characterized by forwardly extending feet joined rearwardly so as to provide an integral base structure, with a forwardly open work access area between said feet.

13. Raise drilling mechanism according to claim 8, wherein said drilling rig comprises a main frame including upright pairs of inboard and outboard plates, with a work table and a stiffening member running laterally between the inboard plates, with other stiffening members running laterally between the inboard and outboard plates, and with mounting socket means for said guide columns disposed between inboard and outboard plates.

14. Raise drilling mechanism for downwardly drilling a pilot hole from an upper level to a lower level underground and for drilling a raise hole along the path of the piot hole in a single upward pass, said mechanism comprising: a base member rigidly anchorable to the ground at the upper level; a drilling rig detachably supportable on said base member and adjustable angularly thereof; and crawler type transport means for said drilling rig, the said crawler type transport means being adapted to carry said drilling rig disposed horizontally thereon and further comprising means for tilting said drilling rig from such horizontal position to the desired angle for drilling while the drilling rig is supported on the ground anchored base member.

15. Raise drilling mechanism according to claim 14, comprising double-acting hydraulic cylinder means for tilting the drilling rig in relation to the crawler type transport means.

16. A raise drilling mechanism for downwardly drilling a pilot hole from an upper level to a lower level underground and for drilling a raise hole along the path of the pilot hole in a single upward pass, said mechanism comprising: a drilling rig for rotating and axially transferring a sectioned drill stem along a drill line in forming the pilot hole during a downward pass and drilling the raise hole during an upward pass, said drilling rig comprising: a ground anchored base plate and doubleacting hydraulic cylinder assemblies anchored to said base plate for such axial transfer of the sectioned drill stern; and said mechanism further comprising a hydraulic control system for said hydraulic cylinder assemblies having means for selectively counterbalancing the progressively increasing weight of the drill stem as the pilot hole drilling operation proceeds; means for sensing the extent of loading of said hydraulically powered means and for automatically providing relatively fast drill stem transfer with low load and relatively slow drill stem transfer with high load; and means for selectively controlling the transfer rate under high load.

References Cited by the Examiner UNITED STATES PATENTS 1,781,707 11/1930 Sheldon 173-4 2,320,874 6/1943 Lehmann 173-4 2,334,312 11/1943 Caldwell 173-44 2,516,182 7/1950 Bury 173-28 2,733,896 2/1956 Gunning 173-43 2,775,439 12/1956 McCarthy 173-145 X 2,792,198 5/1957 Braun 173-28 2,856,155 10/1958 Putt 173-22 X 2,956,782 10/ 1960 Mistrot 173-43 3,011,567 12/1961 Turner 175-53 3,088,531 5/1963 Garrett et al 173-43 X BROUGHTON G. DURHAM, Primary Examiner.

MILTON KAUFMAN, C. OCONNELL, Examiners.

D. H. BROWN, L. KESSLER, Assistant Examiners.

Claims

1. THE METHOD OF DRILLING A LARGE DIAMETER RAISE HOLE TO RUN BETWEEN AN UPPER LEVEL AND A SHAFT OR THE LIKE AT A LOWER LEVEL UNDERGROUND, COMPRISING: RIGIDLY EMPLACING A BASE MEMBER IN FIXED POSITION ON THE FLOOR OF THE UPPER LEVEL AT THE DESIRED DRILL POINT AND IN SUBSTANTIALLY SURROUNDING RELATION TO THE AXIS OF THE HOLE TO BE FORMED; MOUNTED A ROTARY DRILLING RING ON SAID BASE MEMBER TO SPACE THE DRILL OF THE RIG AT THE DISERED DRILL ANGLE; FORMING A PILOT HOLE FROM THE UPPER LEVEL TO THE LOWER LEVEL IN A DOWNWARD PASS WITH A SMALL CUTTERHEAD MOUNTED AT THE END OF A SECTIONED DRILL STEM ARRANGED CONCENTRICLALLY WITH THE HOLE AND FED PROGRESSIVELY DOWNWARDLY BY THE DRILLING RIG; REMOVING THE SMALL CUTTERHEAD FROM SECTIONED DRILL STEM AT THE LOWER WHEN THE PILOT