FIELD

[0001] This specification relates to underground machines and methods for boring large excavations, including shafts, tunnels, drifts and inclines/declines in rock.

BACKGROUND

[0002] When mining in rock, shafts and drifts are sometimes required. A shaft is a predominantly vertical hole through rock. A drift is a predominantly horizontal hole through rock. Shafts and drifts are both types of excavations. Vertical mining shafts are typically used for transporting large mining equipment and supplies from the surface to deep underground. The shafts may also be used to transport the mined ore from underground to the surface. Accordingly, mining shafts are wide and deep. Similarly, mining drifts are wide and long. [0003] To construct vertical mining shafts in hard rock, a well-known Drill and Blast

(D&B) method is typically used. This method comprises forming several small and shallow holes (about 25 mm in diameter and 2 meters deep) in a carefully laid pattern and then placing explosives in the holes. The explosives are then detonated and the rock collapses. The resulting rubble is removed, the shaft walls are reinforced, and the drilling and blasting process is repeated until the desired hole size and depth is achieved. Although this is the preferred method for constructing vertical shafts, it is slow and imprecise. It can also be unsafe because it requires the use of explosives to break the rock.

[0004] For boring large dimeter horizontal tunnels (also referred to as drifts), tunnel boring machines (TBMs) are used. TBMs bore horizontal tunnels using a large rotating cutting head with disk cutters located on the front face. The cutting head rotates about a longitudinal axis defined by the tunnel that is being bored. The cutting head and disks are forced, using extreme and consistent pressure, into the face of the rock being bored to fracture the hard rock surface into chips. The rock chips fall off the rock face being bored under the force of gravity, and into openings in the cutting head where they are transferred to a belt conveyor running through the machine and transported out of the tunnel. As the TBM bores the rock, it is also performing other operations on the tunnel that it has just bored. For example, the TBM will typically reinforce the walls of the tunnel with rock bolts or place precast concrete panels against the tunnel walls. [0005] TBMs are capable of boring large diameter tunnels with lengths of 2km to greater than 30km. In addition, TBMs limit the disturbance to the surrounding rock walls, are safer, and produce more smooth and precise tunnels as compared to a D&B related process. However, an extremely large and consistent force against the cutting head and disk cutters is required to fracture the rock. The back end of the TBM provides these large forces to the cutting head and disk cutters. To do so, the TBMs are typically constructed as long and heavy machines without any pivot points between the cutting head and the back end of the machine. This is because conventional pivot points cannot withstand the significant forces required to effectively press the cutting head into the rock face. Because there are no pivot points, TBMs have limited ability to turn. Conventional TBMs, having a very high turning radius of approximately 150m, are therefore not suitable for smaller turning radius requirements of certain drifts, including most underground mine drifts.

[0006] Attempts have been made to modify and use TBMs to bore vertical mining shafts. In such attempts, the cutting head is pressed against the rock face at the bottom of the shaft as it rotates. The rock is chipped away from the rock face and passes through openings in the cutting head similar to the use of TBMs for boring horizontal drifts. Typically, the rock chips that manage to pass through the openings are collected in buckets within the machine and hoisted out of the shaft. However, because the rock face being bored is always the lowest point in the shaft, the gravitational force that is acting against the rock chips causes most of the rock chips to accumulate instead on the bottom of the shaft against the working face of the rock. These rock chips accumulate between the rock face to be bored and the cutting head creating a barrier between the disk cutters and the rock working face. During boring, the cutting head is pressed down against these rock chips rather than the rock face itself, thereby slowing the boring process as the chips are reground rather than fracturing the rock face. This regrinding of the rock chips that have already broken away from the shaft face also severely reduces the wear life of the disk cutters.

[0007] Technology for helping remove rock chips (produced by disk cutters) out of vertical shaft has been in development. Canadian Patent Application 2,731,400 describes a vertical shaft boring machine using disk cutters. That application teaches a TBM type cutting head that uses a rotating cutting wheel that is arranged vertically and rotated about a horizontal axis that is perpendicular to axis of the vertical shaft being bored. The cutting wheel is arranged such that the annular edges of the wheel contact the rock face rather than the flat side of the wheel as used in conventional TBMs. The cutting wheel also rotates about a vertical axis relative to the shaft. Several shovel-like scrapers are disposed on the rotating wheel to collect and direct the excavated material to a large filler hole in the middle of the side face of the cutter wheel. The excavated material is transported to a loading hopper in the middle of the cutter wheel and onto a conveyor belt. A vertical section of the conveyor belt transports the excavated material upwards and out of the shaft.

BRIEF DESCRIPTION OF THE FIGURES

[0008] Figure 1 shows a side view of an underground excavation machine for boring shafts according to an embodiment of the invention.

[0009] Figure 2 shows a cross-section of an underground excavation machine for boring shafts according to another embodiment of the invention.

[0010] Figure 3A shows a cross-section of another embodiment of an underground excavation machine in accordance with the invention.

[0011] Figure 3B shows a flow chart of steps for boring an excavation according to an embodiment of the invention using the excavation machine shown in Figure 3A.

[0012] Figure 4 shows a bottom view of a percussion hammer arrangement for an underground excavation machine relative to a rock face in accordance with an embodiment of the invention.

[0013] Figure 5 shows a side view of an example percussion hammer mount angle arrangement for an underground excavation machine according to an embodiment of the invention.

[0014] Figure 6A shows a cross-section of another embodiment of an underground excavation machine for boring a shaft in accordance with the invention.

[0015] Figure 6B shows a flow chart of steps for boring an excavation according to another embodiment of the invention using the excavation machine shown in Figure 6A.

[0016] Figure 7 shows a cross-section of another embodiment of an underground excavation machine for boring a shaft in accordance with the invention.

[0017] Figure 8 shows a cross-section of another embodiment of an underground excavation machine for boring drifts in accordance with the invention.

[0018] Figure 9A shows a cross-section of another embodiment of an underground excavation machine for boring drifts in accordance with the invention.

[0019] Figure 9B shows a side-view of a cross section of the underground excavation machine of Figure 9A in accordance with the invention. [0020] Figure 10 shows a cross-section of another embodiment of an underground excavation machine for horizontal boring applications in accordance with the invention.

[0021] Figure 11A shows an underground excavation machine for boring drifts according to an embodiment of the invention.

[0022] Figure 11B shows an underground excavation machine for boring drifts according to an embodiment of the invention.

[0023] Figure 11C shows two underground excavation machines in excavations according to embodiments of the invention.

[0024] Figure 12 shows an underground excavation system according to an embodiment of the invention using a machine similar to the machine in Figure 11A.

[0025] Figure 13 shows an underground excavation system according to an embodiment of the invention using a machine similar to the machine in Figure 11A.

DETAILED DESCRIPTION

[0026] The invention is an underground excavation machine, and a method for boring underground excavations. The excavations may be wide and deep in the case of shafts, and wide and long in the case of drifts such as may be required in mining or tunnel boring applications. The machine and method comprise using hydraulic percussion hammers driven by a hydraulic power unit (HPU) to pulverize the entire rock face being bored to receive the machine. The HPU is located on the machine itself and forms a hydraulic power distribution circuit with the percussion hammers. Because the machine is boring wide excavations, the machine is sufficiently large to accommodate the HPU. HPUs are large and heavy, so are conventionally only used above ground. Placing the HPU on the machine such that they both travel underground together, helps minimize energy loss between the HPU and the percussion hammers by minimizing the distance therebetween. The percussion hammers drive drill bits into the rock face being bored. The percussion hammers may be directly connected to the drill bits without any intervening drill string. The percussion hammers may be located on a carriage which causes the position of the drill bits to change relative to the rock face. For example, the carriage may rotate. The position of the hammers on the carriage and the rotation of the carriage are configured to help ensure that the entire area of the rock face being bored is contacted by at least one bit. The area being bored is sufficiently large to receive the entire machine. Having a select bit contact multiple portions of the area being bored during a select rotation of the carriage helps reduce the total number of hammers and bits required to bore the area. The percussion hammers pulverize the rock face into a coarse sand which may be more easily removed from the excavation than rock chips. The coarse sand may be removed by vacuuming or slurry pumping, for example. The machine may have rock-grippers for contacting the rock on the sides of the excavation to help retain, move, and/or position the machine.

[0027] In an embodiment of the invention, an underground excavation machine for boring through rock is provided. The machine comprises hydraulic percussion hammers configured to drive drill bits and a carriage retaining the hydraulic percussion hammers and drill bits. The carriage is configured to move the percussion hammers to impact an entire area of the rock that is sufficiently large to form an excavation to receive the machine. The machine comprises a hydraulic power unit (HPU) disposed on the machine for powering the hydraulic percussion hammers, the HPU forming a hydraulic power distribution circuit with the hydraulic percussion hammers. The machine may comprise drill bits directly connected to the percussion hammers. The carriage may be configured to rotate. The drill bits may collectively contact the entire area of the rock during a select rotation of the carriage. The excavation may be a vertical shaft. The excavation may be a horizontal tunnel. The excavation may be inclined or declined. The direction of the excavation may define a boring axis, and the carriage may rotate about the boring axis. Each drill bit may be configured to individually rotate about its own axis relative to the carriage. The machine may comprise grippers configured to extend into the side walls of the excavation to anchor a portion of the machine in a position. The machine may comprise actuators for advancing an unanchored portion of the machine a distance into the excavation relative to the anchored portion of the machine. The machine may comprise a vacuum, slurry pump, or conveyor for removing the bored rock from the front face of the excavation. The machine may comprise a drive motor disposed between the carriage and a back portion of the machine, the motor for rotating the carriage.

[0028] In another embodiment of the invention, a method for boring an excavation in rock is provided. The method comprises powering percussion hammers with a hydraulic fluid from an HPU, impacting the entirety of an area of the rock with percussion hammers and rotating the percussion hammers about a boring axis. The method further comprises advancing the percussion hammers into the area that has been bored and advancing the

HPU into the area that has been bored. Boring the area may comprise directly driving drill bits into the rock with the percussion hammers. The excavation may be a vertical shaft, and the method may comprise vacuuming or slurry pumping the bored rock from the bottom of the shaft. The method may comprise anchoring the HPU in a position when rotating the percussion hammers. The method may comprise advancing the percussion hammers when the HPU is anchored. Anchoring the HPU may comprise gripping the side walls of the excavation being bored. The excavation may be a horizontal drift, and the method may comprise removing bored rock from the drift using a vacuum, slurry pump or conveyor.

[0029] In another embodiment of the invention, a method for underground excavation is provided. The method comprises positioning drill bits in an arrangement, pulsing the drill bits against the entire rock face, and moving at least a portion of the drill bits in the arrangement to sweep over an area of the rock face to be bored that is the size of the arrangement. Pulsing the drill bits comprises providing hydraulic pressure to the drill bits. The method may comprise moving the whole arrangement. Moving the arrangement may comprises moving the individual drill bits over predetermined paths covering the entire area of the rock face. The predetermined paths of the drill bits may overlap. Pulsing the drill bits against the entire rock face may comprise contacting drill bit inserts against the entire rock face. The drill bit inserts may be made of a steel alloy or carbide composite and contacting the inserts against the rock face may comprise pulverizing the rock into a coarse sand-like debris.

[0030] Figure 1 shows an underground excavation machine 100 for constructing shafts with a diameter greater than 4 meters and which can extend to depths over 1000 meters. Shaft mining (also referred to as shaft sinking), includes excavating vertical holes in hard rock. A shaft begins at the ground surface and is excavated vertical, or near vertical into the ground, to the desired depth. The underground excavation machine 100 may comprise a back end 115 and a front end 117. The front end 117 provides mechanisms for boring through rock according to an embodiment of the present invention. The back end 115 provides room for personnel to perform additional shaft construction activities. The underground excavation machine 100 may only comprise the front end 117, or only comprise the front end 117 with certain modules shown in the back end 115, depending upon the application. In another embodiment, the underground excavation machine may be configured to construct drifts. The machine for constructing drifts may similarly comprise only a front end or a combination of the front end with some or all of the modules of a back end. Certain applications may only require the machine to comprise a front end.

[0031] The back end 115 of the machine 100 may comprise a ground support deck

119, shaft lining and control decks 111 and a sheave deck 113 as shown in Figure 1. The control and working decks are suitable for use during boring activities. This allows workmen to engage in shaft liner installation and/or temporary ground support while rock boring. The underground excavation machine 100 is lowered into the shaft from a headframe positioned on the ground surface level. Lowering the whole machine into the shaft is done by conventional means, typically using winch/hoist cables connected to sheaves or pulley wheels on the sheave deck 113. In an example, the machine may be lowered using a friction/shear connection to the rock wall or shaft liner.

[0032] Figure 2 shows an underground excavation machine 200 according to an embodiment of the invention. The machine 200 comprises a mainframe 210, a hydraulic power unit (HPU) 220, rock grippers 240 and actuators 232, hydraulic percussion hammers 270 attached to a rotating carriage 216, and drill bits 272. The HPU 220 provides hydraulic fluid to power the hydraulic percussion hammers 270 via a hydraulic power distribution circuit. The hydraulic percussion hammers 270 are simultaneously rotated while directly driving the drill bits 272 to impact a rock face 282. By rotating the drill bits 272 on the rotating carriage 216 through a select rotation, the drill bits are collectively able to contact the entire rock face 282 that is being bored. The percussion hammers 270 are arranged on the rotating carriage 216 such that during a rotation cycle of the carriage, each portion of the face of the rock being bored is contacted by at least one of the drill bits at a point in time during the rotation cycle. The rotation cycle is selected in combination with any required lateral adjustments of the rotating carriage to help ensure that the area of the whole rock face 282 is impacted by the oscillating drill bits 272. In this way, the completion of a rotation cycle results in a rock face that has been completely bored a select distance into the excavation. As a result, no other mechanism is required to contact the rock face to complete boring of the full area of the face of the rock. The contact force of the drill bits 272 (driven by the hydraulic percussion hammers 270 powered by an onboard HPU 220) against the rock face 282, pulverizes the contacted rock into a coarse sand-like debris.

[0033] Conventional disk cutting technology used to bore through rock creates relatively large broken rock chips which are difficult to lift off the bottom (face) of a vertical shaft and ultimately remove out of the vertical shaft. Even if the cutting wheel is placed vertically and the rock cuttings are collected through the center of the wheel, not all cutting will enter the wheel, and the large rock cuttings that fall to the bottom of the shaft are still difficult to lift and remove from the face being bored. By using percussion hammers 270 directly engaging drill bits 272 to bore through the entire surface of a rock face 282, the resulting rock debris has a consistency like that of coarse sand. Rock debris having a consistency like that of course sand is easier than rock chips to lift and remove from the rock face.

[0034] Shaft boring operations may flood the shaft with a liquid to flush out the rock cuttings. The coarse sand-like rock debris created by the machine 200 may instead be removed from the shaft face for example using a vacuum or slurry pump. Vacuum or slurry pumping may be used during the normal course of operation when the underground excavation machine, including any workmen on board, is still in the shaft. In particular when workmen are involved in additional activities such as shaft liner installations or temporary ground support, inside the shaft, flooding is not a suitable option for removing rock debris, while vacuum or slurry pumping are acceptable since the shaft itself is not flooded. In another example, a conveyor may be used to remove the sand-like debris created by the machine, particularly in horizontal boring applications.

[0035] Drill strings used by conventional drilling systems (such as those conventionally used for drilling holes of about 100 mm in diameter), to raise, lower and rotate the drill bits as well as to supply drilling fluid, such as water or air, to the drill bits from the surface, may pose problems if they are attempted to be used for larger diameter/deep hole boring. The drill strings are susceptible to a number of additional stresses as they are made longer to accommodate deeper holes. Providing power from the surface through the drill string to a hammer at the end of the drill string, for example in Down the Hole (DTH) methods, suffers from loss of power as the distance between the power source on the ground and the percussion hammers/drill bits increases. In Top of Hole (TOH) systems where the percussion hammers are positioned at the top of the drill string, the force of each percussion of the hammer is progressively lost between the initial percussion and the drill bit at the end of the drill string. In addition, when the drill string is made up of a number of drill pipes to extend its length, the drill string will have an increased amount of rotational deflection as the total length increases. This additional rotational deflection leads to poor transmission of rigid rotational energy to the drill bits. For these reasons, drilling systems that use drill strings are limited to hole depths of approximately 1000 m.

[0036] By placing the HPU 220 on the mainframe 210 that travels through the excavation with the rotating carriage 216, the distance between power source and drill bits

272 is maintained at a short and proximate distance. Having the HPU 220 directly in the shaft rather than on the surface also negates the need, and problems associated with, using a drill string. Further, having the percussion hammers 270 directly contacting the drill bits 272 allows for the full percussion force to be transmitted to the drill bits. In this way, the energy loss between the HPU 220 and the hydraulic percussion hammers 270 is very small. Although the distance between the HPU 220 and the hydraulic percussion hammers 270 may vary slightly as the machine moves through the shaft, the average distance remains relatively consistent. The HPU 220 and the hydraulic percussion hammers 270 are always within a close proximity to one another. In an example, the distance between the HPU and the percussion hammers does not exceed about 10 meters throughout the boring process. [0037] Providing a direct connection between the hydraulic percussion hammers 270 and the HPU 220, allows energy to be directly supplied to the hydraulic percussion hammers. By pressurizing the hydraulic fluid in the HPU 220 on the mainframe 210, the amount of power required to power the percussion hammers 270 is significantly minimized as compared to providing power from the surface. In addition, because the hydraulic percussion hammers are located directly behind the drill bits, the full force of the hammer’s momentum is able to be transferred directly to the drill bits 272. In DTH systems where the percussion force is driven by air or water that is pressurized in the drill rig on the surface, the hammer momentum against the drill bits will be less because the power supplied from the surface will have diminished within the drill string before reaching the drill bits.

[0038] Electric power may be provided from the ground surface to the HPU 220 using electric cables. The HPU uses this electrical power to pressurize the hydraulic fluid directly on the machine. A hydraulic power distribution circuit allows for continuous hydraulic power to be provided directly from the HPU 220 to the percussion hammers 270. The hydraulic power distribution circuit may be an open-loop or closed-loop circuit. In an open-loop circuit, a fluid reservoir on the machine, that is in, near or a part of, the HPU, provides hydraulic fluid for pressurization and distribution to the percussion hammers. Once used, the fluid is returned to atmospheric pressure in the fluid reservoir before being re-pumped or re pressurized for distribution back to the percussion hammers. In a closed-loop circuit the hydraulic fluid is pressurized and distributed to the percussion hammers, similar to the open loop circuit. However, taking advantage of the fact that the pressured fluid will still be above atmospheric pressure after passing through the percussion hammers, the closed-loop circuit re-pressurizes the already partly pressured fluid received from the percussion hammers and re-distributes the fluid without the fluid first being returned to an atmospheric pressure and/or returned to a fluid reservoir. Additional fluid may be pressurized from the fluid reservoir to top-up the residual fluid distribution, when required. The closed-loop configuration therefore consumes less energy to operate as compared to an open-loop configuration because it pressurizes the fluid from a semi-pressurized state rather than from the lower atmospheric pressure. In both the open-loop and closed-loop hydraulic power distribution circuits, the whole distribution system is closed to the environment. The fluid in both open and closed loop hydraulic circuits is therefore maintained in a contained environment and is not susceptible to contaminants from the surrounding environment such as dirt, rock, and dust. Hydraulic power is therefore provided to the percussion hammers in the form of a pressurized hydraulic fluid. The fluid may be oil or water, for example. In many applications, oil is the preferred hydraulic fluid because it does not freeze and lubricates the components of the machine which it contacts.

[0039] Conventional DTH methods use an open-system fluid distribution where, for example, water is exhausted out of the end of the drill bit to flush the rock cuttings up and out of the hole. The water is then pumped up to the surface where the rock cuttings and other contaminants are cleaned and/or filtered since contaminants in the water can damage the percussions hammers. The water is not pressurized during this cleaning/filtering step. Once de-contaminated, the water is pumped back into the shaft to power the percussion hammers again.

[0040] In accordance with an embodiment of the invention, the machine 200 uses hydraulic fluid that is continuously circulated between the HPU 220 and the hydraulic percussion hammers 270. The hydraulic fluid is pressurized in the HPU 220, provided to the hydraulic percussion hammers 270, and then re-pressurized for re-distribution to the percussion hammers. A high energy transfer efficiency between the HPU and the percussion hammers is provided by this hydraulic power distribution circuit. The hydraulic power distribution circuit further provides a contained environment for the fluid so that contaminants, such as dirt or rock, cannot became entrained in the fluid. The contained environment is not exposed to open atmosphere as is the case in an open-system. The fluid in the hydraulic power distribution circuit therefore does not need additional cleaning steps before being returned to the HPU.

[0041] The rock grippers 240 and actuators 232 of the machine 200 work together to periodically anchor and advance the machine 200 through the excavation. This allows the rotating carriage 216 to advance into the excavation without the use of a drill string.

Impacting of the whole rock face occurs when the rotating carriage 216 is turned and advanced further into the excavation and the percussion hammers 270 are provided with hydraulic power from the HPU 220 situated on the mainframe 210. The hydraulic percussion hammers 270 directly drive the drill bits 272 into the rock face 282. In addition, all the loads produced by actuating the rotating carriage 216 and the drill bits 272 into the rock face are resisted by the direct connection of the rock grippers 240 to the surrounding rock walls 280. This helps provide a constant rotating torque to the rotating carriage regardless of the total length of the excavation that has been bored.

[0042] Using hydraulic percussion hammers 270 avoids needing the extremely large and consistent force that is required to activate rock fracturing mechanisms, such as those used in TBMs and disc cutters. Using the momentum of the hydraulic percussion hammers 270 to directly oscillate the drill bits 272 against the rock face 282 helps avoid this problem with conventional disk cutting systems. In addition, as each drill bit oscillates, it encounters moments in contact with the rock face 282 and moments of relief, in a cycle. Accordingly, the drill bits are not always in contact with the rock and are not susceptible to the same wear rate as disk cutters that are continuously stressed against the hard rock during boring. When a drill bit is not in contact with the rock face, then it also allows rock debris to move away from the rock face.

[0043] Figure 3A shows an underground excavation machine 300 according to a preferred embodiment of the invention. The machine 300 comprises a mainframe 310, hydraulic percussion hammers 370 and drill bits 372 attached to a rotating carriage 316, and a front end mount frame 312 disposed between the mainframe 310 and the rotating carriage 316. The front end mount frame is guided in the shaft relative to the mainframe using guidance mechanisms 334. In addition, the machine 300 is protected from loose rock debris and dust during boring by a shield 346, 348. The shield comprises a lower rock shield 348 fixed to the front end mount frame and an upper rock shield 346 fixed to the mainframe 310. [0044] An HPU 320 is placed directly on the machine mainframe 310. Supply 322 and return 324 lines connect the HPU 320 to a hydraulic power distribution network 326, or manifold. The distribution network 326 connects each of the hydraulic percussion hammers to the supply 322 and return 324 lines. The entire hydraulic power network from the HPU to the percussion hammers creates an open or closed loop hydraulic power distribution circuit. Hydraulic oil, or another type of hydraulic fluid, is pressurized in the HPU 320 and distributed to the hydraulic percussion hammers 370. The hydraulic fluid is then re-pressurized and re circulated directly back to the percussion hammers or otherwise returned or recycled back to the fluid reservoir before re-pressurization and re-distribution. This allows a consistent stream of hydraulic power to be provided to the percussion hammers 370 directly from within the machine 300, regardless of distance into the shaft. The hydraulic fluid can be used to power each of the hydraulic percussion hammers 370 equally, or to variably power the hydraulic percussion hammers (such as at different times and/or in different amounts) based on the application. For example, more power can be provided to the percussion hammers around the periphery of the rotating carriage 316 as compared to those in the center. This may be required based on the rock properties. Keeping the HPU 320 directly on the mainframe 310 maintains the HPU’s proximate and close distance to the hydraulic percussion hammers 370 no matter the distance the machine 300 travels into the excavation. By maintaining a close distance between the HPU 320 and the hydraulic percussion hammers 370, the energy transfer efficiency is maintained.

[0045] The hydraulic percussion hammers 370, drill bits 372 and the rotating carriage

316 may be connected to the front end mount frame 312 by a slewing ring mount frame 392. The slewing ring mount frame 392 comprises a slewing ring 396, lateral position adjusters 394, drive pinions 398 for engaging the slewing ring, and a motor 390 for powering the drive pinions. The slewing ring mount frame 392 further comprises the main bearings and mating teeth for engaging the drive pinions 398 to rotate the slewing ring 396. Rotation of the rotating carriage when connected to a slewing ring may be dependent on the slewing ring 396 rotation. The slewing ring 396 rotational position is controlled to vary the rotation angle in each direction. This in turn allows the rotating carriage 316 to oscillate within a selected arc, or a select rotation. By sweeping over the selected path for a select drill bit arrangement, the hydraulic percussion hammers 370 and drill bits 372 attached to the rotating carriage can impact the entire rock face 382 being bored. The selected path may be an arc. One or more rotations of the carriage may be required to have each portion of the entire rock face 382 contacted by at least one bit during a sweep path.

[0046] Alternatively, the slewing ring 396 can be continuously rotated in a clockwise or counterclockwise direction. Hydraulic fluid, power and communication may be transferred from the slewing ring mount frame 392 to the front end mount frame 312 via flexible lines or a swivel joint that can accommodate the specific amount of rotation relative to the front end mount frame 312, in either direction. In addition, the lateral position of the rotating carriage

316 can be adjusted using the lateral position adjusters 394. This will allow the lateral position of the hydraulic percussion hammers 370 and drill bits 372 to be finely tuned during operation. By finely tuning the percussion hammers 370 and drill bits 372, the direction of the bored excavation can be controlled.

[0047] Each drill bit 372 comprises one end engaged by the hydraulic percussion hammers 370 and a rock contact end 374 for impacting the rock face 382. The rock contact end 374 comprises an indented or dimpled surface. The raised portions of the rock contact end 374 can be hardened ball shaped inserts. The inserts cover a substantial portion of the rock contact end 374 of the drill bit. At least the inserts can be made of specialized hardened material such as a steel alloy or carbide composite, for example diamond, such that impact of the inserts on the rock face will pulverize the contacted face and produce a course sand like debris. The direct oscillation of the hydraulic percussion hammers 370 against the drill bits 372 drives the inserts of the rock contact end 374 of the drill bits 372 directly into the rock face 382. While the drill bits are collectively rotated by the rotating carriage, each drill bit can also rotate (freely or by another drive motor) while impacting the rock face 382.

[0048] Similar to the embodiment 200 as shown in Figure 2, the machine 300 comprises rock grippers 340,350 and actuators 332. In this embodiment, two sets of rock grippers are used. A first set of rock grippers 340 extends from the mainframe 310. A second set of rock grippers 350 extends from the front end mount frame 312. The actuators 332 connect the mainframe 310 to the front end mount frame 312. Actuators 344,354 are used to extend and retract the rock grippers 340,350 between the machine and the rock wall. The rock grippers 340,350 are able to extend from each of the frames 310,312 of the machine to the rock wall by passing through cut-outs 342, 352 in the rock shields 346, 348.

[0049] During a boring cycle, the rock grippers 340 that are attached to the mainframe are extended through the upper rock shield 346 cut-out 342, to anchor the mainframe 310 to the rock wall 380. Simultaneously, or shortly thereafter, the actuators 332 advance the front end mount frame 312 further into the excavation, or shaft. Once the actuators 332 are extended to a preferred distance, the rock grippers 350 that are attached to the front end mount frame 312 anchor the front end mount frame 312 in the newly advanced position in the shaft. To do this, the rock grippers 350 extend through the lower rock shield 348 cut-outs 352 to engage with the rock wall 380. The rock grippers 340 attached to the mainframe then disengage from the rock wall 380 and retract. Simultaneously, or shortly thereafter, the actuators 332 also retract to bring the mainframe 310 forward, towards the newly positioned front end mount frame 312. This inch-worm movement of the mainframe 310 relative to the front end mount frame 312, ensures that the HPU 320 on the mainframe 310 is always close/proximate to the front end mount frame 312, and by virtue of their attachment, close to the hydraulic percussion hammers 370. This method of non-continuous shaft boring also allows for additional activities such as shaft liner installation to be performed on the back end of the underground excavation machine at the same time as boring.

[0050] Throughout the process of advancing the mainframe and the front end mount frame further into the shaft, the upper 346 and lower 348 rock shields which are fixed to their respective frames, also advance into the shaft. An interface 347 allows the upper and lower rock shields to maintain a tight seal against the rock wall during the inch worm movement of the frames. The interface 347 is defined by an overlap of the adjacent rock shields. For example, as the front end mount frame 312 moves downwards and away from the machine main frame 310, the lower rock shield 348 slides over the upper rock shield 346 at the interface 347 thereby maintaining a tight seal against the rock wall 380.

[0051] The underground excavation machine 300 is used for non-continuous boring to allow execution of other activities simultaneously to boring. The non-continuous boring method comprises distinct boring cycles where the total boring distance in each cycle is completed by a single stroke of the actuators 332 connecting the mainframe 310 to the front end mount frame 312. Anytime the machine mainframe 310 is stationary, other activities such as, temporary ground support and shaft liner installation, can be carried out. These other activities can therefore be carried out even when the front end mount frame 312 is in motion. Alternatively, boring can be continuous if no other shaft construction activities are required.

[0052] Figure 3B shows a flow chart of steps for boring an excavation according to an embodiment of the invention using an excavation machine similar to that shown in Figure

3A. The boring cycle begins when the rock grippers 350 of the front end mount frame 312 are retracted from the rock wall 380 and the actuators 332 between the mainframe 310 and the front end mount frame 312 are also retracted such that the mainframe and the front end mount frame are as close as possible. The first step S301 is when the rock grippers 340 of the mainframe are extended to anchor the mainframe 310 into the rock wall 380. The mainframe 310 is stationary and conducive for additional shaft construction activities. In the next step S303, the actuators 332 advance the front end mount frame 312 towards the rock face 382. As the front end mount frame advances, one or more rotation cycles of the rotating carriage are executed. The rotating carriage 316 is therefore turned a selected number of degrees in one or more directions to achieve a desired select rotation. The rotating carriage may continue to rotate as long as the front end mount frame is advancing. The rock face is impacted S305 when the HPU 320 powers the hydraulic percussion hammers 370 to oscillate the drill bits 372 such that the rock contact end 374 of the drill bits impacts and bores the rock face 382 a distance equal to the distance extended by the actuators 332. As the front end mount frame 312 moves downwards and away from the machine main frame 310, the lower rock shield 348 slides over the upper rock shield 346 at the interface 347 maintaining a tight seal against the rock wall 380. After deepening the shaft by the desired distance, the next step S307 comprises stopping the rotating carriage 316 and the percussion hammers 370. The rock grippers 350 of the front end mount frame are then extended into the rock wall 380 to anchor S309 the front end mount frame 312 in place. The rock grippers 340 of the mainframe 310 are retracted off the rock walls 380. The actuators 332 are retracted to lower the machine mainframe towards the anchored stationary front end mount frame S311. When the mainframe reaches the desired position closest to the front end mount frame, the rock grippers 340 of the mainframe are extended into the rock walls 380, and the rock grippers 350 of the front end mount frame are retracted from the rock walls 380 to begin another boring cycle.

[0053] During each boring cycle the position of the machine and the direction of boring may be tuned or adjusted. The angle of the front end mount frame 312 relative to an imaginary plane of the frame that is parallel to the machine mainframe 310 may be tuned by independently varying the extension amount of each of the actuators 332 during boring. In addition, the lateral position of the rotating carriage may also or alternatively be tuned using the lateral position adjusters 394. During extension and retraction of the actuators 332 a minor rotational adjustment can occur between the front end mount frame 312 and the machine mainframe 310 to tune the rotational position of the machine mainframe relative to the rock walls 380. When the actuators 332 are retracted and the rock grippers 340 of the mainframe are disengaged from the rock walls 380, the verticality of the whole machine may be subtly tuned by independently varying the extension of the rock grippers 350 of the front end mount frame. The machine can be tuned to account for different rock profiles encountered during excavations and to control the excavation direction.

[0054] Figure 4 shows an example arrangement 400 of hydraulic percussion hammers relative to the rock face 482. The arrangement 400 comprises hydraulic percussion hammers aligned in a cross made up of two intersecting lines of multiple percussion hammers. When rotated the hydraulic percussion hammers 470 drive drill bits to impact the rock face along predetermined paths 471. The predetermined paths are chosen such that the paths cover the whole rock face to be bored. The predetermined paths may overlap to ensure complete coverage of the rock face. The hydraulic percussion hammers 470 are arranged so that the hammers in each intersecting line cover alternating paths 471 that collectively sweep over the whole rock face during a select rotation cycle. In other examples, the arrangement may be a single line of percussion hammers positioned side by side. A select rotation cycle can be a rotation of the rotating carriage through a select number of degrees for each of one or more rotations of a clockwise and/or counterclockwise direction. For example, in a sweep, the carriage may be configured to rotate clockwise 30 degrees, then counterclockwise 60 degrees, then clockwise 30 degrees, then counterclockwise 30 degrees, and finally clockwise 60 degrees. Alternatively, a rotation cycle may comprise a number of pulses of the rotating carriage in a first direction followed by a second direction. For example, a rotation cycle might comprise turning the rotating carriage 90 degrees clockwise and then 90 degrees counterclockwise. One or multiple rotation cycles can be carried out during each boring cycle, as required. Any arrangement of percussion hammers/drill bits may be used so long as, after turning the rotating carriage a select rotation, all areas of the rock face 482 have been impacted by at least one of the drill bits. The predetermined paths 471 and the degrees through which the rotating carriage turns are selected to accommodate the rock face and rock profile being bored. In addition, selecting arrangements that minimize the total number of percussion hammers while ensuring impact coverage of the entire rock surface during a rotation cycle reduces the power consumption needs of the whole machine.

[0055] In an embodiment, the drill bits and percussion hammers are positioned in an arrangement. A portion of the arrangement or the whole arrangement may be moved during a boring cycle such that at least one drill bit contacts each portion of the entire area of the working face during the boring cycle. A single boring cycle may comprise each portion of the entire area of the working face being contacted once and only once by only one of the drill bits.

[0056] Each drill bit may have a one-to-one correspondence with a percussion hammer. A drill bit and percussion hammer pair may be moved independently of each of the other drill bit and percussion hammer pairs. In an embodiment a drill bit and percussion hammer pair may be moved in a direction that is parallel to the rock face during a boring cycle. For example, the drill bit and percussion hammer pair may be moved from a first position that is closer to the center of the excavation, to a second position that is closer to the outside of the excavation. The drill bit and percussion hammer pair may be attached to the machine on a worm screw that rotates to cause the pair to move from a first position of the screw to a second position of the screw.

[0057] The drill bit and percussion hammer pair may also be rotated about a center axis of the excavation by pivoting the worm screw in a plane that is parallel to the rock face. In an embodiment, a group of drill bit and percussion hammer pairs may be moved laterally across the rock face, and/or may be rotated to cause the entire rock face to be impacted during a boring cycle. While moving the arrangement, each individual drill bit may freely rotate around its own central axis that is perpendicular to the rock face being bored. Each drill bit may also pulsate without rotating or may move with some combination of stationary and rotational pulsation during each boring cycle.

[0058] In another embodiment, one or more retention means may be used to retain the arrangement of drill bits/percussion hammers and to connect the arrangement to the machine. The retention means may advance the whole arrangement of drill bits, or a portion thereof, towards the rock face. The one or more retention means can be configured to move together, or independently. For example, either or both a rotational retention mechanism and/or a laterally moving retention mechanism may be used. When moving the arrangement laterally, the drill bits sweep over the rock face a selected distance. For example, the drill bits may move a selected distance and then return to their original position. Various sized drill bits may be used and arranged in alternating and/or overlapping rows in order to cover the whole rock face. In another example, the same retention mechanism may be configured to both rotate and move with lateral motion. In yet another example, two rotational retention mechanisms may be used. The two rotational mechanisms may rotate simultaneously but in opposite directions, rotate together or rotate in any other sequence. When two or more retention mechanisms are used, the arrangement of drill bits on one or more mechanisms may be stopped during a particular boring cycle. For example, an arrangement of drill bits covering a central area of the rock face may be engaged while an arrangement covering a peripheral area of the rock face is not. This can provide for boring different rock profiles, if desired. A subsequent boring cycle may be used where the peripheral drill arrangement is engaged to impact the remaining rock face while the central arrangement is stopped. The profile of the rock contact end of the drill bits may be circular, or square or any other polygonal shape optimized for the chosen arrangement of the drill bits and their retention mechanism such as to allow for the whole rock face to be impacted.

[0059] Figure 5 shows an example arrangement 500 of hydraulic percussion hammers 570 mounted on the rotating carriage. The hydraulic percussion hammers 570 can be mounted on the rotating carriage 516 in an arrangement that is generally perpendicular to the front end mount frame 512. However, the angle at which the percussion hammers are mounted on the rotating carriage 516 can also be varied. In the example arrangement 500, the percussion hammers 570 that are closer to the center of the machine are generally perpendicular to the front end mount frame. The percussion hammers that are closer to the periphery of the machine are angled slightly. In this configuration, the percussion hammers along the periphery are able to impact the rock face 582 abutting the shaft walls 580 more effectively. The flexibility to vary the mount angle of some or all of the percussion hammers allows for easier creation and tuning of gaps between the rock walls 580 and the outer face of the rock shield, in particular the outer face of the lower rock shield 548. This is useful when different ground conditions are encountered which require different ground relaxation distance allowances. Additionally, varying the mount angle allows for creation of more space around the periphery of the percussion hammers allowing for an increase in the thickness of the lower rock shield 548. An increased lower rock shield thickness provides higher shielding strength around the percussion hammers and rotating carriage. The flexibility further allows many different possible rock face 582 profiles to be excavated. For example, a sump area can be created in the central section of a shaft being bored to help with water collection and/or diversion if personnel are required to access the rock face. More effective directional heading changes and sharper turning radii, particularly in horizontal applications, of the whole rotating carriage 516 are also possible by minimizing the side loading on the drill bits located on the periphery of the rotating carriage.

[0060] Figure 6A shows an underground excavation machine 600 according to an embodiment of the invention. The underground excavation machine 600 comprises a series intermediate frame 614. The series intermediate frame 614 is disposed between the mainframe 610 and the front end mount frame 612, and is circumferentially bordered by a middle rock shield 649. The mainframe and the series intermediate frame are connected to one another by a first set of actuators 631. The intermediate frame 614 and the front end mount frame 612 are connected by a second set of actuators 633. Guidance mechanisms

639 guide the front end mount frame movements relative to the series intermediate frame. Guidance mechanisms 637 guide the series intermediate frame 614 movements relative to the machine mainframe 610. This embodiment of the invention allows for an extended boring depth in each boring cycle as compared to the embodiment in Figure 3. In addition, having series connected actuators can reduce the total extension distance of the guidance mechanism 639 between the front end mount frame 612 and the series intermediate frame 614. Reducing this total extension distance results in a reduction in the cantilevered loads that need to be transmitted through the guidance mechanism 639.

[0061] Similar to the embodiment in Figure 3, rock grippers 640 extend from the mainframe 610 and periodically anchor the mainframe to the rock wall 680. Additionally, rock grippers 660 extend from the series intermediate frame 614 and periodically anchor the series intermediate frame to the rock walls 680. This allows the same inch-worm movement previously described between the mainframe and the front end mount frame to occur between the mainframe and the series intermediate frame. In this embodiment, the front end mount frame 612 does not require an independent set of rock grippers. However, in additional embodiments, the front end mount frame can be connected to rock grippers. When the front end mount frame is also connected to rock grippers, the same inch-worm movement occurs between the series intermediate frame and the front end mount frame.

[0062] In an example boring cycle as shown in Figure 6B for the excavation machine shown in Figure 6A, the start position of the machine 600 is when the two sets of actuators

631, 633 are fully retracted, placing the series intermediate frame 614 and the front end mount frame 612 close to the mainframe 610. The rock grippers 640, 660 are extended through rock shield cut-outs 642,662 into the rock wall 680, thereby anchoring the mainframe and the series intermediate frame to the rock wall S601. The boring cycle begins by having the actuators 633 thrust the front end mount frame 612 towards the rock face 682.

Simultaneously, the rotating carriage 616 is advanced and turned S603 and the hydraulic percussion hammers 670 engage the drill bits 672 to impact the rock face S605. A select rotation of the carriage allows the collective drill bits 672 to contact the whole surface of the rock face 682. The force of contact with the rock face is powerfully driven by the hydraulic percussion hammers 670 powered by the hydraulic power unit 620 positioned on the mainframe 610 close by. Pressurized hydraulic oil is provided through supply lines 622 to the hydraulic fluid distribution network 626, or manifold, for powering each of the percussion hammers. The hydraulic oil is then recycled back to the HPU using return lines 624.

[0063] As the front end mount frame 612 advances into the shaft and away from the series intermediate frame 614, the lower rock shield 648 slides over the middle rock shield 649 at the interface 668 maintaining a tight seal against the rock wall 680. Once the actuators 633 have extended to the desired distance, the rotating carriage 616 and percussion hammers 670 are stopped S607. The rock grippers 660 of the series intermediate frame are then retracted from the rock walls 680. The first set of actuators 631 lower the series intermediate frame 614 down by the distance that was bored S609 and the second set of actuators 633 are retracted. Simultaneously, the middle rock shield 649 slides over the upper and lower rock shields 646, 648 at each of their respective interfaces 666, 668 maintaining a tight seal against the rock wall 680. The rock grippers 660 are then extended into the rock walls 680 again to anchor the series intermediate frame S611 and the second set of actuators 633 thrusts the front end mount frame 612 towards the rock face 682, again. As this thrusting action occurs, the rotating carriage 616 is once again turned using the drive motors 690 and the percussion hammers 670 oscillate the drill bits 672 to bore the whole rock face 682. Once the actuators 633 have fully extended to the desired distance deepening the shaft, the rotating carriage 616 and percussion hammers 670 are stopped. The rock grippers 660 of the series intermediate frame are retracted from the rock walls and the first set of actuators 631 lower the series intermediate frame 614 down by the distance bored. The second set of actuators 633 are simultaneously retracted. The rock grippers 660 are then extended into the rock walls again and the rock grippers 640 are fully retracted off the rock walls to allow the machine mainframe 610 to advance further down the shaft S613 using the actuators 630. As the machine main frame is lowered down the shaft, the actuators 631 are simultaneously retracted while the front end mount frame 612 and series intermediate frame 614 stay fixed relative to the rock walls 680. Once the machine mainframe has been lowered to the desired position, the rock grippers 640 are extended into the rock walls to complete a full boring cycle. The cycle may then be repeated. In other embodiments, any simultaneous steps may instead occur in series.

[0064] Figure 7 shows a vertical underground excavation machine 700 according to an embodiment of the invention. The vertical underground excavation machine 700 can be used for continuous, near continuous or semi-continuous rock boring in vertical blind shaft boring applications. The continuous nature restricts the ability to perform certain other activities such as temporary ground support and shaft liner installations during boring due to the machine’s constant motion. However, continuous boring can provide for generally quicker timelines for excavation. [0065] The vertical underground excavation machine 700 includes a machine mainframe 710 that is connected to the front end mount frame 712 via guidance mechanisms 736. A parallel intermediate frame 718 is arranged between the mainframe and the front end mount frame. The parallel intermediate frame 718 is coupled to the front end mount frame 712 by actuators 738 and guided between the machine main frame and the front end mount frame by the guidance mechanisms 736. Rock grippers 756 extending from the parallel intermediate frame 718 periodically anchor the frame to the rock walls 780. A single rock shield 759 encases the whole machine and is fixed relative to the front end mount frame 712 and the machine mainframe 710. The rock shield 759 includes rock shield cut-outs 776 that allow lateral movement of the parallel intermediate frame rock grippers 756 through the rock shield. The cut-outs 776 also allow vertical movement of the rock shield relative to the rock grippers 756 when the rock grippers are engaged with the rock wall 780. This allows the rock shield to continue protecting the machine when the parallel intermediate frame 718 is stationary but the machine mainframe 710 and/or the front end mount frame 712 are advancing forward into the shaft.

[0066] In an example, the vertical boring cycle begins when the rock grippers 740 of the mainframe are retracted from the rock walls 780 and the rock grippers 756 of the parallel intermediate frame are extended and engaged with the rock walls 780. The actuators 738 thrust the front end mount frame 712 towards the rock face 782. As this thrusting action occurs, the rotating carriage 716 is turned while the HPU 720 powers the percussion hammers 770 to oscillate the drill bits 772 to bore the rock face 782. The machine mainframe 710 and the front end mount frame 712 are directly coupled via the guidance mechanism 736 and so as this thrusting action occurs, they both move down the shaft at the same rate. Once the actuators 738 have extended to the desired distance and the shaft is deepened by a certain amount, the rotating carriage 716 and percussion hammers 770 are stopped. The rock grippers 740 of the mainframe are extended into the rock walls 780 and the rock grippers 756 of the parallel intermediate frame are retracted from the rock walls 780. The actuators 738 are then retracted to lower the parallel intermediate frame 718 down the shaft. The rock grippers 756 of the parallel intermediate frame are then extended into the rock walls 780 and the rock grippers 740 of the mainframe are retracted from the rock walls to complete a full boring cycle.

[0067] As previously described with respect to Figures 3A and 3B, during each boring cycle the position of the machine and the direction of boring can be tuned or adjusted. The verticality of the front end mount frame 712 relative to the parallel intermediate frame 718 (i.e. the angle of the front end mount frame 712 relative to an imaginary plane of the frame that is parallel to the parallel intermediate frame 718) can be subtly tuned by independently varying the extension amount of each of the actuators 738 during boring. During extension and retraction of the actuators 738 a minor rotational adjustment can be made between the parallel intermediate frame 718 and the machine mainframe 710 to tune the rotational position of the machine mainframe relative to the rock walls 780. When the actuators 738 are retracted and the rock grippers 740 are disengaged from the rock walls, the verticality of the whole machine can also be subtly tuned by independently varying the extension of the rock grippers 756 of the parallel intermediate frame.

[0068] Figure 8 shows an underground excavation machine 800 according to another embodiment of the invention. The underground excavation machine 800 is optimized for non-continuous and generally horizontal boring applications, for example for boring drifts, headings or large horizontal holes. The machine 800 allows high directional flexibility for rock boring in horizontal applications. The machine is also suitable for simultaneous execution of boring alongside other drift construction activities.

[0069] The machine 800 comprises a mainframe 810 with means for actuating 878 the mainframe through the drift. For example driving tracks and/or wheels can be used to move the mainframe through the drift being bored. The mainframe is coupled to the front end mount frame via a set of actuators 888. The actuators 888 are arranged in pairs to allow similar actuation flexibility between the front end mount frame and the machine mainframe to that of a ‘Stewart platform’. The actuators 888 arranged in the ‘Stewart Platform’ type setup allow for a high degree of flexibility of the front end mount frame 812 relative to the machine mainframe 810. These degrees of flexibility include pure vertical and/or lateral adjustments, directional heading adjustments, rotational adjustments along the general centerline of the drift being bored and/or any combination of these adjustments. The front portion of the machine 800 comprising the front end mount frame 812 and the rotating carriage 816 is similar to the embodiment described in Figure 3.

[0070] The mainframe 810 is connected to a set of rock grippers 840 and the front end mount frame 812 is connected to another set of rock grippers 850. In another embodiment, the mainframe is connected to rock grippers and the front end mount frame is not connected to rock grippers. In yet another embodiment, the front end mount frame is connected to rock grippers and the mainframe is not connected to rock grippers. In yet another embodiment, neither the mainframe nor the front end mount frame are connected to rock grippers. In an embodiment of the invention where both the mainframe and the front end mount frame are connected to rock grippers, the actuators 888 can be attached between the mainframe rock grippers 840 and front end mount frame rock grippers 850 instead of between the mainframe 810 and the front end mount frame 812 bodies.

[0071] The boring cycle using the machine 800 is similar to the boring cycle as described in the embodiment of Figure 3A and 3B. However, movement of the mainframe 810 further through the excavation is completed by the actuators 888 as well as the actuating means 878, for example tracks and/or wheels. This minimizes the pull force required from the actuators 888.

[0072] Figure 9A shows a side view of an underground excavation machine 900 according to another embodiment of the invention. The underground excavation machine 900 is configured for generally horizontal boring applications and has a reduced directional flexibility as compared to the embodiment in Figure 8 but operates in a continuous or semi- continuous manner. This allows for more expedient drift boring.

[0073] The machine 900 includes a machine mainframe 910 connected to wheels

978. In other embodiments, the mainframe may be connected to driving tracks or any other suitable means for actuating the machine mainframe through a drift being bored. A main beam 928 is used to connect the mainframe 910 to the front end mount frame 912. The main beam is disposed generally along the central axis relative to the drift being bored. A universal joint connection 984 is used to couple the main beam 928 to the mainframe 910. The joint connection 984 allows the main beam to move without moving the machine mainframe 910. In accordance with other embodiments, the hydraulic power unit 920 travels on, and with, the machine mainframe through the drift being bored.

[0074] The main beam 928 is also connected to a parallel intermediate frame 918 by actuators. The main beam 928 is connected to a first set of actuators 902. This allows the main beam 928 to move relative to the parallel intermediate frame 918 in the general direction being bored. The main beam is further connected to a second set of actuators 906 for adjusting the vertical direction of the main beam relative to the parallel intermediate frame

918. The parallel intermediate frame is connected to yet another set of actuators 908. The actuators 908 allow adjustment of the vertical position of the parallel intermediate frame relative to the bottom of the drift being bored. The actuators 906, 908 are also used to adjust the directional heading of the main beam 928 in a vertical plane. The parallel intermediate frame is also connected to retractable rock grippers 956 for anchoring the parallel intermediate frame to the rock walls 980 of the drift being bored. In another embodiment, the actuators 902 can be connected to rock grippers 956 rather than to the parallel intermediate frame 918.

[0075] Figure 9B shows a different side view of the underground excavation machine

900. The main beam 928 can again be seen connecting the front end mount frame 912 to the mainframe 910. However, in this perspective of machine 900, the actuators 902 can be seen connecting the parallel intermediate frame to the main beam to provide for a “Stewart Platform” type flexibility. The actuators 902 allow movement of the main beam 928 relative to the parallel intermediate frame 918 in the general direction being bored. Figure 9B further shows linear actuators 904 between the main beam and the parallel intermediate frame that allow general adjustment of the lateral direction of the main beam 928 relative to the parallel intermediate frame 918. The actuators 904 can be used to adjust the directional heading of the main beam 928 relative to the parallel intermediate frame 918 in a horizontal plane.

[0076] A method of horizontal excavation using the underground excavation machine

900, comprises a start position where the actuators 902 between the parallel intermediate frame and the main beam are retracted and the rock grippers 956 of the parallel intermediate frame are extended into the rock walls. In this starting configuration, the parallel intermediate frame 918 is close to the front end mount frame. Boring is started when the actuators 902 thrust the main beam 928 and therefore the whole front end mount frame, towards the rock face 982. As this thrusting action occurs, the rotating carriage 916 is turned using the drive motors 990 and the percussion hammers 970, powered by the HPU 920, oscillate the drill bits 972 to bore the rock face. By virtue of being coupled via the universal joint connection 984 both the machine mainframe 910 and the main beam 928 move down the drift at the same rate. The wheels or other actuating means of the machine mainframe reduce the pull force required to be expelled by the actuators 902 to move the mainframe through the drift. Once the actuators 902 have extended to the desired distance, extending the drift being bored by a desired amount, the rotating carriage and percussion hammers are stopped. The rock grippers 956 of the parallel intermediate frame are retracted from the rock walls and the actuators 902 are retracted to pull the parallel intermediate frame 918 back towards the front end mount frame. The rock grippers 956 are then extended into the rock walls to complete a full boring cycle.

[0077] Figure 10 shows an underground excavation machine 1000 according to an embodiment of the invention. Underground excavation machine 1000 is suitable for continuous or semi-continuous horizontal boring applications.

[0078] The underground excavation machine 1000 comprises a machine mainframe having wheels 1078 for actuating the mainframe through the drift being bored. A mechanical joint connection 1086 between the mainframe and the front end mount frame allows the front end mount frame to move in any direction without moving the mainframe 1010. A parallel intermediate frame 1018 is disposed between the front end mount frame and the mainframe 1010. A set of actuators 1009 connect the parallel intermediate frame to the front end mount frame. The actuators 1009 are arranged in a ‘Stewart Platform’ setup to allow for a high degree of flexibility of the front end mount frame 1012 relative to the parallel intermediate frame 1018. The degrees of flexibility include pure vertical/lateral adjustments, directional heading adjustments, rotational adjustments along the general centerline of the drift being bored, as well as any combinations thereof. The parallel intermediate frame can be anchored to the rock walls 1080 using rock grippers 1056. In an additional embodiment, the actuators

1009 can be attached to the rock grippers 1056 instead of to the parallel intermediate frame 1018.

[0079] A method for boring rock using the underground excavation machine 1000 comprises a boring cycle start position where the actuators 1009 are retracted and the rock grippers 1056 of the parallel intermediate frame 1018 are extended into the rock walls 1080. In this starting configuration, the parallel intermediate frame 1018 is close to the front end mount frame 1012. The full boring cycle begins by using actuators 1009 to thrust the front end mount frame 1012 towards the rock face 1082. As this thrusting action occurs, the rotating carriage 1016 is turned using the drive motors 1090 and the percussion hammers 1070, powered by the HPU 1020 on board the mainframe 1010, oscillate the drill bits 1072 to bore the rock face 1082. The vertical and/or lateral position of the rotating carriage 1016, within the shaft cross section, can be subtly tuned using the lateral position adjusters 1094. The machine main frame 1010 and the front end mount frame move down the drift at the same rate. The actuators 1009 do not need to pull all of the weight of the machine mainframe

1010 as the tracks/wheels 1078 are engaged to assist in the movement. Once the actuators

1009 have extended to the desired distance, extending the drift being bored by a certain amount, the rotating carriage 1016 and percussion hammers 1070 are stopped. The rock grippers 1056 are retracted from the rock walls 1080 and the actuators 1009 are retracted to pull the parallel intermediate frame 1018 back towards the front end mount frame 1012. The rock grippers 1056 are then extended into the rock walls 1080 to complete a full boring cycle. [0080] Figure 11A shows an underground excavation machine 1100A according to an embodiment of the invention. The underground excavation machine 1100A is configured for continuous or semi-continuous horizontal boring applications. Machine 1100A may be used to bore curves in a drift on a vertical plane. For example, the machine 1100A may be used to ramp a drift on an incline or decline.

[0081] Figure 11B shows an underground excavation machine 1100B according to an embodiment of the invention. The machine 1100B is similar to the machine 1100A shown in Figure 11A, the main difference being that the machine 1100B may be better suited to boring smaller radius drift curves on a horizontal plane. For example, the machine 1100B may be used to cut corners, passing bays, or intersections in the drift. Excavation machine 1100A and excavation machine 1100B may be each referred to herein as excavation machine 1100.

[0082] The underground excavation machine 1100 comprises a machine mainframe

1110 with an onboard HPU, and a boring head 1118 coupled to the mainframe 1110. The boring head 1118 comprises percussion hammers 1170. The boring head may be moved relative to the mainframe. For example, the boring head may be rotated relative to the mainframe using radial actuators 1188. The radial actuators 1188 may be connected between the mainframe and the boring head 1118 to move the boring head relative to the mainframe 1110. The HPU is for powering the percussion hammers 1170. The mainframe 1110 further comprises tracks 1178 for advancing the machine 1100 into the drift, and through the drift being bored. For example, driving tracks and/or wheels can be used to move the machine 1100 through the drift being bored. Tracks for moving the machine may allow greater maneuverability of the machine in the drift. For example, the machine can be easily moved or readjusted to align with the desired direction of boring. The machine may further be quickly reversed out of an excavation in emergencies or for inspection of the rock face or to re-arrange equipment.

[0083] The boring head 1118 comprises a carriage 1116 retaining the percussions hammers 1170 and a thrust boom 1128 that guides the linear thrusting of the carriage 1116 into the rock face using the linear actuators 1190. The carriage 1116 comprises a center segment 1120, lateral guides 1130 extending from the center segment 1120, and two retaining segments 1150, each retaining segment 1150 configured to slide along one of the lateral guides 1130. Each retaining segment 1150 retains a portion of the percussion hammers 1170. There may be more or less than two retaining segments 1150. Where there are multiple retaining segments, the retaining segments may be attached to different lateral guides 1130 to allow the retaining segments 1150 (and therefore the groups of percussion hammers 1170) to move apart or together relative to one another. This collapsing or expanding of the retaining segments relative to one another changes the cross-sectional area of the profile of the percussions hammers so as to change the total width of the machine 1100 during operation. This can help the machine 1100 become smaller than the excavation that it bored.

[0084] The radial actuators 1188 may be connected to the retaining segments or the central segment 1120 or the lateral guides of the carriage 1116. One end of the thrust boom

1128 is connected to the mainframe 1110. The thrust boom may be rotated relative to the mainframe 1110. For example the thrust boom 1128 may be rotated along a pivot point or axis at the interface between the mainframe and the thrust boom 1128. The center segment

1120 is able to slide along the end of the thrust boom opposite the end connected to the mainframe 1110. The lateral guides 1130 extend from the center segment 1120. The carriage may comprise less or more than two lateral guides. For example, each lateral guide may be perpendicular to the center segment 1120 and connected to the center segment to form a cross or “T” shape. Alternatively, a single lateral guide 1130 may be attached to the end of the center segment 1120 opposite the end of the thrust boom. Each lateral guide may be connected to at least one retaining segment 1150. The retaining segments 1150 retain the percussion hammers 1170. An equal number of percussion hammers 1170 may be retained by each retaining segment 1150. Alternatively, an unequal number of percussion hammers may be retained by each retaining segment. The percussion hammers on each retaining segment may be aligned side-by-side to form a rectangular profile. The percussion hammers may have spaces therebetween. The retaining segments are configured to slide or laterally move along the length of the lateral guides 1130 using lateral actuators. A lateral actuator may be connected between a retaining segment 1150 and the central segment

1120, such as to move the retaining segments relative to the central segment. The retaining segments may slide towards each other or away from each other, or in the same direction by extending and retracting the lateral actuators. Sliding the retaining segments away from each other forms a gap or space between the retaining segments and increases the cross- sectional area taken up by the percussion hammers 1170. The maximum space formed between the two retaining segments may be for example, the diameter of one drill bit. In other examples, the maximum space formed between the two retaining segments may be greater or less than the diameter of one drill bit. Sliding the retaining segments 1150 towards each other may minimize the cross-sectional area taken up by the retaining segments 1150 such as to provide more tolerance or space between the excavation walls and the percussion hammers 1170 disposed on the periphery of the retaining segments. The retaining segments may be moved towards each other until there is virtually no space between the retaining segments. This may help avoid the percussion hammers on the outer periphery of the retaining segments from getting caught against the drift walls when the machine is reversed out of the drift.

[0085] Referring to machine 1100A, the retaining segments 1150 are configured to extend across the width of the drift. Lateral movement of the retaining segments using the lateral actuators may be used to move the percussion hammers to the left or right of the excavation. The radial actuators 1188 move the boring head 1118 in a generally vertical direction (up and down relative to the floor / bottom of the excavation). For example, the boring head may be rotated such that the percussion hammers contact the rock face over an arced path from a first position to a second position. For example, from the top of the excavation to the bottom of the excavation, or from the bottom of the excavation to the top of the excavation or between two other vertically separated positions along the rock face to be bored. Where an incline in the drift is desired, the radial actuators 1188 may be configured to incrementally raise the lowest position of the hammers against the rock face and raise the highest position of the hammers against the rock face, such as to bore a gradual inclining ramp. Where a decline in the drift is desired, the radial actuators 1188 may be configured to incrementally lower the lowest position of the hammers against the rock face and lower the highest position of the hammers against the rock face, such as to bore a gradual declining ramp. In another example, the radial actuators 1188 may be configured to incrementally decrease or increase the range of motion of the percussion hammers over a length of the excavation to provide a ramp incline or decline.

[0086] Referring to machine 1100B, the retaining segments 1150 are configured to extend along the height of the drift, such as to form a column of percussion hammers 1170.

Lateral movement of the retaining segments using the lateral actuators may be used to move the percussion hammers vertically up or down in the excavation. The radial actuators 1188 move the boring head 1118 in a generally horizontal direction (left and right relative to the direction of boring). For example, the boring head may be rotated such that the percussion hammers contact the rock face over an arced path from a first position to a second position. For example, from the left of the excavation to the right of the excavation, or from the right of the excavation to the left of the excavation or between two other horizontally separated positions along the rock face to be bored. Where a corner or other cut-out in the drift is desired, the radial actuators 1188 may be configured to incrementally decrease or increase the range of motion of the carriage over a length of the excavation to provide the desired corner or cutout.

[0087] Figure 11C shows excavation machines 1100A and 1100B in excavations.

Machine 1100A may be used to bore drifts having a straight path, for example to form a drift with an inclined or declined ramp. Machine 1100B may be used to form corners or other cutouts in the drift. Small radius curves, for example to turn tighter corners, may be formed by increasing the speed of the radial actuators 1188 providing the incremental changes to the range of motion of the carriage.

[0088] Movement of the carriage causes the percussion hammers 1170 to move across an area of the rock to be bored. Moving the percussion hammers across an area of the rock comprises sweeping the percussion hammers across the area of the rock to be bored and impacting the entirety of that area of the rock during a sweep. A sweep may comprise for example, rotating the percussion hammers along a radial path or arc between the top of the excavation and the bottom of the excavation. A sweep may comprise moving the percussion hammers along a radial path or arc from left to right (or right to left) of the excavation. A sweep of the percussion hammers may comprise moving the percussion hammers laterally. For example, a sweep may comprise moving the percussion hammers along a linear path from left to right (or right to left) or up and down. The radial actuator 1188 may be used to move the percussion hammers across a selected radial path or arc. Lateral actuators between the retaining segments 1150 and central segment 1120 may be used to move the hammers across a selected linear or lateral path. Lateral actuators may also be used to move the retaining segments 1150 towards each other to close the space therebetween or away from each other to form a space therebetween. A sweep may comprise any combination of the foregoing paths.

[0089] A sweep of the percussion hammers may comprise a rotation or pivot of the boring head about one or more axes. The rotation or pivot of the boring head about an axis may comprise impacting an area of the rock to be bored over the area of a selected arc or path. The pivot or rotation axis of the boring head may be perpendicular or parallel to the floor of the excavation or to the side wall of the excavation. The pivot or rotation axis may be at the interface of the boring head and the mainframe 1110 of the machine or another point. The boring head may also be configured to rotate or spin about one or more axes. The boring head may be configured to rotate or spin about an axis that is parallel to the floor of the excavation in the direction of boring. Such a rotation may help cause a change in the orientation of the percussion hammers relative to the rock face being bored. Any one or more of the boring head movements may be applied in combination during a boring cycle such as to allow the percussion hammers to impact the entirety of the area of the rock to be bored in that boring cycle.

[0090] In an embodiment, the boring head 1118 may be coupled to the main frame

1110 using, for example, a pivot ball or swivel joint. Rotating the boring head about the ball or joint may change the orientation of the percussion hammers 1170 relative to the rock face and the mainframe 1110. For example, rotating the boring head may comprise changing the orientation of the percussion hammers from the orientation of machine 1100A to the orientation of the percussion hammers of machine 1100B, or vice-versa. The pivot ball or swivel joint may allow the boring head to rotate multiple axes, including three degrees of freedom. For example, the boring head may rotate up/down, left/right, and clockwise /counterclockwise relative to the mainframe 1110. The boring head may further rotate about an axis as previously described or about a different axis intersecting the ball such as to sweep the percussion hammers through an arc or path, vertically, horizontally or at a diagonal, over an area of the rock face to be bored.

[0091] Underground excavation machine 1100 may be used for making excavations having square or rectangular cross-sections (i.e. excavations having a square or rectangular profile at the rock face being bored) when the percussions hammers are arranged in that configuration. Because of the nature of the rectangular/square profile bored by a boring head configured accordingly, each adjacent excavation can abut a previous and adjacent excavation (optionally, an adjacent excavation filled with concrete) along the entire abutting plane with minimal unmined ore therebetween, and the unmined ore having a consistent thickness. For example, a first stope formed by the machine 1100 may be filled with backfill, the machine may then begin extraction forming a second stope adjacent to the first stope where the adjoining stopes share a wall from the top of the excavation to the bottom. In this way, nearly all of the ore in an ore body can be extracted without leaving behind ore between excavation paths (such as would result if a boring head were rotated on an axis parallel to the boring direction forming an excavation with a circular / round cross-section). Excavations having a square or rectangular cross-section also by nature have a flat ground for the machine (and other mining equipment) to move on and do not require additional steps or cost to flatten the ground.

[0092] The boring head 1118 comprises an array of hydraulic percussion hammers

1170 configured to drive drill bits 1172 into the rock face to be bored. The drill bits may have square, rectangular, round or other desired polygonal shaped profiles. The arrangement or array of the percussion hammers may be for example a single row connected to the carriage that can extend at least the width or height (depending on orientation) of the mainframe such as to bore an area of the rock that is sufficiently sized to form an excavation to receive the machine 1100. In some examples, the retaining segments of the carriage may retain additional rows / columns of percussion hammers. The additional rows / columns may be the same width / height as the mainframe 1110, or more or less of the width / height of the mainframe. An array of percussion hammers may be sufficiently sized to bore a hole large enough to form an excavation to receive the machine 1100 by moving the retaining segments 1150 away from one another, thereby increasing the cross-sectional area of the percussion hammers 1170. The hydraulic percussion hammers 1170 may be arranged such that, when the retaining segments of the carriage are moved towards each other, the percussion hammers on each of the retaining segments closest to the space between the retaining segments abut, or come closer to, each other. This arrangement may help ensure that the entire area of the rock is contacted during boring.

[0093] In other embodiments, the percussion hammers may be connected to the retaining segments with spaces therebetween. In an example, where the retaining segment may comprise two rows of hammers, for example one row above the other, a second row of hammers may include hammers situated above or below the spaces left in a first row such that the entire rock face is still impacted during a boring cycle. The foregoing may apply to rows of percussion hammers disposed horizontally according to the orientation of machine 1100A or to columns of percussion hammers dispose vertically according to the orientation of machine 1100B.

[0094] Referring again to machine 1100, the arrangement of percussion hammers can be used to bore an excavation without a need for any pre-boring set up activities such construction of a starting structure. By boring the excavation using percussion hammers, as opposed to disk cutters, a much lower thrust force into the rock face being bored is required. Disk cutters need an extremely high thrust force into the rock face being bored in order to chip off rock from the face. Percussion hammers do not require such high thrust forces into the face being bored and therefore the whole machine may not need to be gripped or stabilized against a starting structure to begin boring an excavation. The back force provided by the friction between the tracks/wheels and the ground may be sufficient. This allows the machine to be smaller (both in width and length) and provides greater mobility for moving the machine in and out of a given drift.

[0095] A method for boring rock using the underground excavation machine 1100 comprises a boring cycle start position where the radial actuators 1188 are extended such that the carriage is positioned at a first end of the rock face to be bored. For example, the first end may be the floor of the excavation, the top of the excavation, the left or the right of the excavation. In other examples, a first end may be any start position of the percussion hammers on the rock face. The retaining segments 1150 start in a position where they are fully retracted towards each other such that there is a no gap between the two inner drill bits and there is a gap between each of the two outer drill bits and the sides of the excavation.

The mainframe tracks 1178 move the machine forward to contact the drill bits 1172 of the percussion hammers 1170 against the rock to be bored. The percussion hammers 1170, powered by the HPU on board the mainframe 1110, oscillate the drill bits 1172 to bore the rock face. The radial actuators 1188 incrementally retract to move the boring head, and thereby the percussion hammers, towards a second end of the rock face over a radial path.

Once the percussion hammers reach the second end, the retaining segments 1150 are then laterally extended across the rock face and away from each other on the lateral guides 1130 such that the outer most drill bits are in contact with the sides of the excavation. The radial actuators 1188 then incrementally extend to move the boring head, and thereby percussion hammers, back towards the first end of the rock face over a radial path. A second end of the rock face may be for example the opposite end of the rock face from the first end such that the combination of radially extending/retracting the radial actuators 1188 and laterally moving the retaining segments 1150 across the rock face results in contacting the percussion hammers against the whole rock face to be bored. Each incremental movement of the percussion hammers and drill bits impacts a portion of the rock face directly adjacent the portion previously bored, until the entire face of the rock has been bored and the linear actuators 1190 can incrementally thrust the whole carriage 1116 further into the excavation along the thrust boom 1128. The retaining segments 1150 are then retracted back to their start position where they are fully retracted towards each other. The combination of radially extending/retracting the radial actuators 1188 and laterally moving the retaining segments 1150 across the rock face in order to contact the percussion hammers against the whole rock face is then repeated. This cycle is all repeated until the linear actuators 1190 have reached the end of their stroke distance. The linear actuators 1190 are then retracted to retract the carriage 1116 on the thrust boom 1128 and the whole machine 1100 then advances into the excavation to begin the boring cycle again. The boring cycle may be started with the radial actuators 1188 fully retracted and incrementally extending to move the percussion hammers along the rock face to be bored. In an embodiment, the first boring cycle may be started with the radial actuators retracted. In another embodiment, each boring cycle may begin by resetting the radial actuators to an extended or retracted position. In another embodiment, the retaining segments start in a position where they are fully extended away from each other such that there is a gap between the two inner drill bits and the outer most drill bits are in contact with the sides of the excavation.

[0096] Figure 12 shows an underground excavation system 1200 using a machine according to an embodiment of this disclosure. The system comprises a rock boring machine

1202 connected to a vacuum unit 1204 behind the machine, a mixing hopper 1206 (and dust scrubber) behind the vacuum unit and a high pressure piston pump 1208 behind the mixing hopper. The mixing hopper and machine are connected to a slurry circulation fluid supply line

1210 that may extend down from surface level. The high pressure piston pump is connected to a slurry return line 1212 that may extend to the surface level. The slurry circulation fluid supply line provides clean slurry circulation fluid from the surface to the machine to be sprayed from the percussion hammers 1213 on the drill bits and rock face. The clean slurry fluid lubricates the drill bits and dampens the rock face to be bored. The lubricating slurry fluid may reduce the friction between the bits and the rock face being impacted, and thereby increase the wear life of the drill bits thereby requiring less frequent drill bit changes and lowering costs of the boring operations. Rather than a slurry circulation fluid, any lubricating fluid may be used on the bits and rock face to reduce friction. The lubricating fluid mixes with the produced sand-like rock debris to form a sand and slurry mixture 1214. A rock vacuum line 1216 connected to the vacuum unit collects the sand and slurry mixture and transports the mixture to the mixing hopper. The sand and slurry mixture may be mixed with additional clean slurry circulation fluid 1218 in the mixing hopper to reduce the density of the mixture so that the slurry may be pumped more easily. The high pressure piston pump 1208 connected to the mixing hopper 1206 is then used to pump the slurry mixture to the surface for further processing via the slurry return line 1212.

[0097] Figure 13 shows another underground excavation system 1300 using a machine according to an embodiment of this disclosure. The system comprises a rock boring machine 1302, a mobile mixing hopper 1304 and low pressure pump 1306 positioned closely behind the machine and a stationary pump station 1308 with a high pressure piston pump 1310. The mixing hopper and machine are connected to slurry circulation fluid supply line 1314 that may extend down from surface level. The high pressure piston pump 1310 is connected to a slurry return line 1312 that may extend to the surface level. The slurry circulation fluid supply line 1314 provides clean slurry circulation fluid to the machine 1302 to be sprayed from the percussion hammers 1316 on the drill bits and rock face. The clean slurry circulation fluid may be sprayed at the interface between the drill bits and rock face. The clean slurry fluid lubricates the drill bits and dampens the rock face to be bored. The clean slurry fluid may also provide a cooling effect at the interface between the drill bits and the rock face. The lubricating slurry fluid may reduce the friction between the bits and the rock face being impacted, and thereby increase the wear life of the drill bits. Rather than a slurry circulation fluid, any lubricating fluid may be used on the bits and rock face to reduce friction. The lubricating fluid may be delivered to the bits and rock via a lubrication line attached to the boring machine 1302. The outlet of the lubrication fluid line may be at the drill bits. The machine further comprises mechanical means 1318, such as a screw conveyor or auger, to lift the dampened sand-like rock debris 1320 from the floor at the front base of the machine and transport the debris to the mixing hopper 1304 behind the machine. Use of a conveyor or auger to lift the debris from the front of the excavation may provide a faster mass flow rate of the sand-like debris 1320 as compared to collecting such debris using a vacuum. For example, the conveyor may transport debris from the front of the excavation to the mixing hopper at the same rate or faster rate than the machine’s rate of cutting rock, thereby allowing the machine to more quickly advance through the excavation. The clean slurry circulation fluid line may provide additional clean slurry 1322 to be mixed with the dampened sand-like debris in the mixing hopper to lower the slurry density as required. The low pressure pump 1306 connected with the mixing hopper pumps the sand and slurry mixture to the pump station 1308. The high pressure piston pump 1310 may then be used to pump the slurry and sand mixture to the surface for further processing via the slurry return line 1312.