CA3106799A1 - Raise forming system and method - Google Patents

Abstract

A method of forming a raise defined by a central axis in a body of rock, the raise being located between upper and lower drifts. Two outer holes are formed on the raise perimeter, on opposite sides of the raise perimeter. A blasthole is formed coaxial with the central axis. With wire saws located in the upper and lower drifts, a wire initially located in the outer holes cuts the rock to form respective slots on the raise perimeter as the wire saws are rotated in unison about the central axis. Each of the slots defines a bridge at an outer hole, the bridges connecting an internal portion of the rock that is inside the raise perimeter with a host portion of the rock. The internal portion is removed by blasts initiated in the blasthole, starting at a lower end of the blasthole that is at the lower drift roof.

Description

RAISE FORMING SYSTEM AND METHOD
FIELD OF THE INVENTION
[0001] The present invention is a method of forming a raise in a body of rock.
BACKGROUND OF THE INVENTION

[0002] In the prior art, excavating raises in underground mining is one of the more difficult tasks in mine development. As is known in the art, in conventional mining construction hoists may be used to enable miners to have reasonably safe access to a workface in the raise, for drilling and blasting when the raise is being formed. Alternatively, raise bore machines have recently been developed that can excavate the raise by boring through the ground.

[0003] However, the known methods of forming raises have disadvantages.
Workers on a construction hoist may still be exposed to risks that are unacceptable, depending on the circumstances. Raise bore machines are extremely expensive, and significant time is required for set-up and also dismantling.
SUMMARY OF THE INVENTION

[0004] For the foregoing reasons, there is a need for a system and a method that overcomes or mitigates at least some of the defects and disadvantages of the prior art.

[0005] In its broad aspect, the invention provides a method of forming a raise defined by a central axis in a body of rock, the raise being located between upper and lower drifts. Two outer holes are formed on the raise perimeter, on opposite sides of the raise perimeter. A blasthole is formed coaxial with the central axis. With wire saws located in the upper and lower drifts, a wire initially located in the outer holes cuts the rock to form respective slots on the raise perimeter as the wire saws are rotated in unison about the central axis. Each of the slots defines a bridge at an outer hole, the bridges connecting an internal portion of the rock that is inside the raise Date Recue/Date Received 2021-01-22 perimeter with a host portion of the rock. The internal portion is removed by blasts initiated in the blasthole, starting at a lower end of the blasthole that is at the lower drift roof.
BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The invention will be better understood with reference to the attached drawings, in which:

[0007] Fig. 1 is a cross-section of a portion of a mine in which a raise is to be formed in a body of rock;

[0008] Fig. 2 is a cross-section of the portion of the mine of Fig. 1 showing two outer holes and a blasthole located therebetween extending between an upper drift and a lower drift;

[0009] Fig. 3A is a cross-section of the portion of the mine of Figs. 1 and 2 showing upper and lower wire saws located in the upper and lower drifts respectively, positioned for alignment with outer holes;

[0010] Fig. 3B is a cross-section of the portion of the mine of Figs.
1,2, and 3A in which the wire saws pull a wire through the outer holes, drawn at a smaller scale;

[0011] Fig. 3C is a cross-section of one of the outer holes and the wire located therein, drawn at a larger scale;

[0012] Fig. 3D is a top view of a part of the floor of the upper drift in which the outline of the raise is shown, with the two outer holes and the inner hole, drawn at a smaller scale;

[0013] Fig. 3E is a top view of the part of the floor of the upper drift showing cuts made by the wire, to partially define an internal portion of the rock to be removed;

[0014] Fig. 4 is a cross-section of the portion of the mine of Figs. 1, 2, 3A, and 3B in which the wire saws have been removed in preparation for blasting, drawn at a smaller scale; and

[0015] Fig. 5 is a cross-section of the portion of the mine of Figs. 1, 2, 3A, 3C, and 4 in which the completed raise is shown.

Date Recue/Date Received 2021-01-22 DETAILED DESCRIPTION

[0016] In the attached drawings, like reference numerals designate corresponding elements throughout. Reference is made to Figs. 1-5 to describe an embodiment of a method of forming a raise 22 in a body of rock 24 (Fig. 5) in accordance with the invention.

[0017] As will be described, once formed, the raise 22 is defined by a raise wall 25 (Fig.
5) that is at least partially parallel with a raise perimeter 26 (Fig. 3D) that has a radius 28 thereof centered on a central axis 30 of the raise 22 (Figs. 1, 3D). It will be understood that the raise perimeter 26 extends through the body of rock 24 between a floor 32 of an upper drift 34 and a roof 36 of a lower drift 38 (Fig. 1).

[0018] In one embodiment, the method includes, first, identifying locations "A1", "A2" on the floor 32 of respective upper ends 40, 42 of first and second outer holes 44, 46 to be formed on the raise perimeter 26 at opposite sides of the raise perimeter 26 (Figs.
1, 2). As can be seen in Fig. 3D, the outer holes 44, 46 preferably are coincident with the raise perimeter 26.
Accordingly, the raise perimeter 26, as illustrated in Fig. 1, also indicates the center lines of the outer holes 44, 46.

[0019] A location "B" on the floor of an upper end 48 of a blasthole 50 is also identified, in Fig. 1. The blasthole 50 is to be formed coaxial with the central axis 30 of the raise 22. Those skilled in the art would appreciate that identification of the locations "A1", "A2", and "B" may be achieved by using any suitable surveying method.

[0020] Next, the first and second outer holes 44, 46 and the blasthole 50 are formed.
Those skilled in the art would appreciate that the holes 44, 46, 50 may be formed by any suitable method, e.g., by drilling with a suitable drill "D" (Figs. 1, 2). As can be seen in Fig. 2, once formed, each of the first and second holes 44, 46 and the blasthole 50 preferably extend between respective upper ends 40, 42, 48 thereof at the floor 32 of the upper drift 34 and respective lower ends 52, 54, 56 thereof at the roof 36 of the lower drift 38.

[0021] The outer holes 44, 46 and the blasthole 50 may have any suitable diameters.
Those skilled in the art would be aware of suitable diameters, and also suitable drills. For example, the diameters may be between one inch and six inches.

[0022] Those skilled in the art would appreciate that the outer holes 44, 46 and the blasthole 50 are formed in accordance with the raise perimeter 26, i.e., the outer holes 44, 46 and Date Recue/Date Received 2021-01-22 the blasthole 50 are formed in accordance with the design of the raise 22 that is to be formed. It will be understood that the outer holes 44, 46 and the blasthole 50 are shown in Figs. 2, 3A, 3B, and 4 as being vertical for clarity of illustration. In practice, because the raise may be designed to be non-vertical, the outer holes and the blasthole may also be non-vertical accordingly.

[0023] Once the holes 44, 46, 50 have been formed, an upper wire saw 58 having an upper sheave 60 preferably is positioned in the upper drift 34, on the floor 32 of the upper drift 34 (Fig. 3A). As can be seen in Fig. 3A, it is also preferred that a lower wire saw 62 having a lower sheave 64 is positioned in the lower drift 38, on a floor 65 of the lower drift 38. Each of the upper and lower sheaves 60, 64 is rotatable about its own sheave rotation axis, to pull a wire 66. The rotation axis of each of the upper and lower sheaves 60, 64 is horizontal, or substantially horizontal. A rotation axis 67 of the upper sheave 60 is shown in Fig. 3D. It will be understood that the rotation axis of the lower sheave 64 is omitted from Fig. 3D for clarity of illustration.

[0024] It will also be understood that the wire 66 forms an endless loop, and that the upper and lower wire saws 58, 62 are positioned to draw the wire 66 pulled over the upper and lower sheaves 60, 64 through the first and second outer holes 44, 46. For example, in Fig. 3B, the wire 66 is moved generally upwardly (i.e., in the direction indicated by arrow "X"
in Fig. 3B) through the second outer hole 46, and generally downwardly (i.e., in the direction indicated by arrow "Y"
in Fig. 3B) through the first outer hole 44. The wire 66 is initially moved through each of the outer holes parallel to the outer hole, or substantially parallel to, the outer hole in which it is located.

[0025] Those skilled in the art would appreciate that, alternatively, the wire 66 may initially be moved generally upwardly through the first outer hole 44, and generally downwardly through the second outer hole 46.

[0026] The wire may be any suitable wire or cable. Those skilled in the art would be aware of suitable wires or cables. For example, the wire may be a diamond wire designed for cutting rock. Those skilled in the art would appreciate that the wire or cable diameter is determined based on the length of the cut to be made, ground types and conditions, and also the time in which the cut is to be made. Depending on the conditions, custom cables may be made.

[0027] As noted above, the outer holes 44, 46 and the blasthole 50 are shown as being vertical for clarity of illustration. It will be understood that, depending on the orientation of the outer holes 44, 46, the movement of the wire 66 through the outer holes 44, 46 may be vertical, substantially vertical, or non- vertical.

Date Recue/Date Received 2021-01-22

[0028] The upper and lower sheaves 60, 64 are positioned relative to the outer holes 44, 46 so that the wire 66 is dragged against an internal wall 68 of each of the holes 44, 46, at the same time as the wire 66 is moved through the holes, parallel to the holes. As will also be described, due to friction, the wire 66 cuts the rock 24 as it is drawn through the first and second outer holes 44, 46 because the wire 66 is dragged against the internal wall 68 of each of the holes 44, 46 (Fig.3D).

[0029] While the wire 66 is drawn through the first and second outer holes 44, 46, the upper and lower sheaves 60, 64 preferably are rotated about the central axis

30 in unison. This rotation causes the wire 66 to be urged in the direction indicated by arrow "C" in Fig. 3C. It will be understood that, in Fig. 3C, the wire 66 is shown in an outer hole when the wire 66 is first engaged with the internal wall 68 of the outer hole.
[0030] The upper and lower sheaves 60, 64 are rotated about their respective rotation axes to pull the wire 66 through the outer holes 44, 46 at the same time as the upper and lower sheaves 60, 64 are rotated about the central axis 30, to urge the wire against the internal walls 68 of the outer holes 44, 46.

[0031] Accordingly, upon the rotation of the upper and lower sheaves 60, 64 about their respective rotation axes, the wire 66 is pulled through the outer holes, and upon rotation of the upper and lower sheaves 60, 64 about the central axis 30, the wire 66 is also dragged against the internal walls 68 of each of the outer holes 44, 46, causing the wire to cut through the rock 24 along the raise perimeter 26. As can be seen in Fig. 3B, due to the rotation of the sheaves 60, 64 about the central axis 30, the wire 66 in the outer hole 44 is urged in the direction indicated by arrow "C1", and the wire 66 in the outer hole 46 is urged in the direction "C211 .

[0032] As can be seen in Fig. 3E, the wire 66 cuts through the rock 24 to partially form the raise wall 25 that is at least partially parallel with the raise perimeter 26. It is preferred that the wire 66 cuts the rock along the raise perimeter 26. Preferably, the wire 66 forms a first slot 70 extending from the first outer hole 44 to a first bridge 71, and the wire 66 also forms a second slot 72 extending from the second outer hole 46 to a second bridge 73 (Fig.
3E).

[0033] From the foregoing, it can be seen that, once the wire 66 has begun to cut the first and second slots 70, 72, the wire 66 is moved generally upwardly through one of the slots, and generally downwardly through the other of the slots. In addition, as the wire 66 is moved generally upwardly and generally downwardly through the slots 70, 72, the wire is urged against working Date Recue/Date Received 2021-01-22 faces in each of the slots, because the wire is urged in the directions indicated by arrows "C1", "C2" in Figs. 3D and 3E. The wire 66 is urged in the directions indicated by arrows "C", "C" as the wire 66 is also moved generally upwardly and generally downwardly through the slots until the working faces of the slots reach first and second predetermined points 82, 84 (Figs. 3D, 3E). The slots 70, 72 preferably end at the first and second predetermined points 82, 84 to define the first and second bridges 71, 73.

[0034] It will also be understood that the width of the slots 70, 72 is exaggerated somewhat in Fig.3E for clarity of illustration. The width of each of the slots 70, 72 is approximately equal to the diameter of the wire, e.g., the width of the slots may be approximately 0.5 inch to approximately one inch, or larger.

[0035] Each of the slots 70, 72 is defined by an inner wall 74 thereof and an outer wall 76 thereof. It will be understood that the outer wall 76 forms part of the raise wall 25, as will be described.

[0036] As can be seen in Fig. 3E, as the wire 66 cuts through the rock 24, moving in the directions indicated by the arrows "C1", "C2", the wire 66 partially severs an internal portion 78 of the rock 24 from a host portion 80 thereof. As will be described, the internal portion 78 is to be removed, in order to form the raise 22. Accordingly, the internal portion 78 is inside the raise perimeter 26.

[0037] As can be seen in Fig. 3D, the first and second points 82, 84 on the raise perimeter 26 are determined, at which the slots 70, 72 formed by the wire 66 end, to form the first and second bridges 71, 73. Once the wire 66 has reached the first and second points 82, 84, the rotation of the upper and lower sheaves 60, 64 about the central axis 30 ceases, and the wire saws 58, 62 stop pulling the wire 66 through the slots 70, 72. At this point, the wire cutting process has been completed. The wire 66 is then removed from the outer holes 44, 46.

[0038] As can be seen in Figs. 3D and 3E, the first and second points 82, 84 preferably are on opposite sides of the raise perimeter 26, i.e., it is preferred that they are located 180 from each other. Accordingly, the first and second bridges 71, 73 preferably are also located 180 from each other.

[0039] As can be seen in Fig. 3E, the internal portion 78 is connected with the host portion 80 by the first and second bridges 71, 73. It will be understood that the first and second bridges Date Recue/Date Received 2021-01-22 71, 73 are designed to support the internal portion 78 temporarily, and the first and second bridges 71, 73 therefore must be sized accordingly. Those skilled in the art would appreciate that the sizes of first and second bridges 71, 73 preferably are determined according to the specific conditions in the rock 24 where the raise 22 is to be formed.

[0040] Those skilled in the art would also appreciate that, depending on ground conditions, it may be advantageous to drill more than two outer holes, and it also may be advantageous to have the wire cut slots between more than one pair of oppositely-positioned holes, so as to define more than two bridges between the internal portion and the host portion.
Using multiple outer holes would involve incurring more costs, however, it would permit each of the bridges to be smaller.

[0041] Once the wire cutting process has been completed and the wire 66 is removed from the outer holes 44, 46, the upper and lower wire saws 58, 62 are removed.

[0042] Preferably, the internal portion 78 of the rock 24 is then blasted, using the blasthole 50, to form the raise 22. Those skilled in the art would appreciate that the internal portion 78 may be blasted in a series of relatively small blasts, starting at the lower end 56 of the blasthole 50.
For example, the blasting may be accomplished using crater blasting, at suitable vertical intervals.
As an example, an initial region 86 of the internal portion 78 that is to be blasted first is shown in Fig. 4. The initial region 86 may be blasted with a crater blast. The explosives are loaded from the upper drift 34. It will be understood that the broken ground falls into the lower drift 38 (as indicated by arrows "Z" in Fig. 4), from which it may be removed.

[0043] Those skilled in the art would appreciate that, in this way, the internal portion 78 is removed from the host portion 80, e.g., in a series of crater blasts. The broken ground from each blast falls into the lower drift 38, and is removed before the next blast. In this way, the internal portion 78 is ultimately removed, forming the raise 22, as illustrated in Fig.
5.

[0044] The broken ground from each successive blast may be removed from the lower drift 38 by any suitable means. Those skilled in the art would be aware of suitable means.

[0045] It will be appreciated by those skilled in the art that the invention can take many forms, and that such forms are within the scope of the invention as claimed.
The scope of the claims should not be limited by the preferred embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole.

Date Recue/Date Received 2021-01-22

Claims

We claim:

1. A method of forming a raise in a body of rock, the raise to be defined by a raise wall that is at least partially parallel with a raise perimeter that has a radius thereof centered on a central axis of the raise, the raise perimeter extending through the body of rock between a floor of an upper drift and a roof of a lower drift, the method comprising:
(a) identifying locations on the floor of respective upper ends of first and second outer holes to be formed on the raise perimeter at opposite sides of the raise perimeter, the outer holes being centered on the raise perimeter;
(b) identifying a location on the floor of an upper end of a blasthole to be formed coaxial with the central axis of the raise;
(c) forming the first and second outer holes and the blasthole, each of the first and second holes and the blasthole extending between respective upper ends thereof at the floor of the upper drift and respective lower ends thereof at the roof of the lower drift;
(d) positioning an upper wire saw having an upper sheave and a lower wire saw having a lower sheave to draw a wire pulled over the upper and lower sheaves through the first and second outer holes, each of the upper and lower sheaves being rotatable about a horizontal rotation axis thereof respectively;
(e) while the wire is drawn through the first and second outer holes, rotating the upper and lower sheaves about the central axis in unison to partially form the raise wall and to partially sever an internal portion of the body of rock that is inside the raise wall;
(f) upon the wire having reached first and second predetermined points on the raise wall at which the internal portion is connected with a host portion of the body of rock by predetermined first and second bridge portions, stopping rotation of the upper and lower sheaves; and (g) using the blasthole, blasting the internal portion of the body of rock to remove the internal portion from the host portion of the rock, to form the raise.

Date Recue/Date Received 2021-01-22