METHOD OF EXTRACTING ORE USING TUNNEL BORING MACHINE

Abstract

A method of extracting mineral ore with a tunnel boring machine can include positioning the TBM in an initial chamber adjacent to a mineral field; boring a first tunnel into the mineral field aligned with the initial chamber, while transporting muck containing the ore away from the first tunnel; and retracting the TBM out of the first tunnel and back into the initial chamber. The method can further include pouring a grout plug at a proximal end of the first tunnel, and boring a second tunnel with the TBM through the grout plug and into the mineral field laterally offset from the initial chamber. The second tunnel can be bored by advancing the TBM from the initial chamber along an S-curve path having a first curve away from the first tunnel and a second curve toward the first tunnel, after which the second tunnel is parallel with the first tunnel.

Claims

1. A method of extracting mineral ore from a mineral field with a tunnel boring machine, the method comprising: positioning the tunnel boring machine in an initial chamber adjacent to the mineral field; boring a first tunnel into the mineral field with the tunnel boring machine, the first tunnel being laterally aligned with the initial chamber, wherein during the boring of the first tunnel, muck produced from the boring containing the mineral ore is transported away from the first tunnel and through the initial chamber; after the tunnel boring machine bores the extent of the first tunnel, retracting the tunnel boring machine out of the first tunnel and back into the initial chamber; pouring a first grout plug ahead of the tunnel boring machine in at least a portion of a proximal end of the first tunnel; boring a second tunnel through the first grout plug into the mineral field with the tunnel boring machine, the second tunnel being laterally offset from the initial chamber, wherein: the tunnel boring machine bores the second tunnel by advancing from the initial chamber along a first S-curve path having a first curve away from the first tunnel and a second curve toward the first tunnel; after traveling along the first S-curve path, the tunnel boring machine is advanced parallel to the first tunnel to the extent of the second tunnel; and during the boring of the second tunnel, muck produced from the boring containing the mineral ore is transported away from the second tunnel and through the initial chamber; and after the tunnel boring machine bores the extent of the second tunnel, retracting the tunnel boring machine out of the second tunnel and back into the initial chamber.

2. The method of claim 1, further comprising: after the tunnel boring machine is retracted out of the second tunnel and back into the initial chamber, pouring a second grout plug ahead of the tunnel boring machine in at least a portion of a proximal end of the second tunnel; boring a third tunnel through the second grout plug into the mineral field with the tunnel boring machine, the third tunnel being laterally offset from the initial chamber on an opposite side of the first tunnel from the second tunnel, wherein: the tunnel boring machine bores the third tunnel by advancing from the initial chamber along a second S-curve path having a first curve away from the first tunnel and a second curve toward the first tunnel; after traveling along the second S-curve path, the tunnel boring machine is advanced parallel to the first tunnel to the extent of the third tunnel; and during the boring of the third tunnel, muck produced from the boring containing the mineral ore is transported away from the third tunnel and through the initial chamber; and after the tunnel boring machine bores the extent of the third tunnel, retracting the tunnel boring machine out of the third tunnel and back into the initial chamber.

3. The method of claim 2, further comprising: after the tunnel boring machine is retracted out of the third tunnel and back into the initial chamber, pouring a third grout plug ahead of the tunnel boring machine in at least a portion of a proximal end of the third tunnel; boring a fourth tunnel through the third grout plug into the mineral field with the tunnel boring machine, the fourth tunnel being laterally offset from the initial chamber on an opposite side of the second tunnel from the first tunnel, wherein: the tunnel boring machine bores the fourth tunnel by advancing from the initial chamber along a third S-curve path having a first curve away from the first and second tunnels and a second curve toward the first and second tunnels; after traveling along the third S-curve path, the tunnel boring machine is advanced parallel to the first and second tunnels to the extent of the fourth tunnel; and during the boring of the fourth tunnel, muck produced from the boring containing the mineral ore is transported away from the fourth tunnel and through the initial chamber; and after the tunnel boring machine bores the extent of the fourth tunnel, retracting the tunnel boring machine out of the fourth tunnel and back into the initial chamber.

4. The method of claim 3, further comprising: after the tunnel boring machine is retracted out of the fourth tunnel and back into the initial chamber, pouring a fourth grout plug ahead of the tunnel boring machine in at least a portion of a proximal end of the fourth tunnel; boring a fifth tunnel through the fourth grout plug into the mineral field with the tunnel boring machine, the fifth tunnel being laterally offset from the initial chamber on an opposite side of the third tunnel from the first tunnel, wherein: the tunnel boring machine bores the fifth tunnel by advancing from the initial chamber along a fourth S-curve path having a first curve away from the first and third tunnels and a second curve toward the first and third tunnels; after traveling along the fourth S-curve path, the tunnel boring machine is advanced parallel to the first and third tunnels to the extent of the fifth tunnel; and during the boring of the fifth tunnel, muck produced from the boring containing the mineral ore is transported away from the fifth tunnel and through the initial chamber; and after the tunnel boring machine bores the extent of the fifth tunnel, retracting the tunnel boring machine out of the fifth tunnel and back into the initial chamber.

5. The method of claim 1, wherein the first and second tunnels are bored to a length from about 1500 m to about 3000 m from a distal end of the initial chamber.

6. The method of claim 1, wherein the mineral ore extracted from the first and second tunnels is transported through the initial chamber by a muck conveyor system operably coupled to the tunnel boring machine.

7. The method of claim 1, wherein the mineral ore extracted from the first and second tunnels is transported from the initial chamber out of a production shaft extending from the ground into the initial chamber.

8. The method of claim 1, wherein the first and second curves each have a radius of about 300 m.

9. The method of claim 1, wherein the initial chamber has a length of about 400 m or greater.

10. The method of claim 1, wherein a vertical height of the first tunnel is different than a vertical height of the second tunnel.

11. The method of claim 3, wherein a vertical position of the first tunnel with respect to the initial chamber is different than a vertical position of the second tunnel, wherein a vertical position of the third tunnel with respect to the initial chamber is different than a vertical position of the fourth tunnel, wherein the first and fourth tunnels have the same vertical position with respect to the initial chamber, and wherein the second and third tunnels have the same vertical position with respect to the initial chamber.

12. The method of claim 1, wherein the first tunnel has a full bore portion positioned above a benched bore portion in a stacked configuration.

13. A method of extracting mineral ore from a mineral field with a tunnel boring machine, the method comprising: positioning the tunnel boring machine in an initial chamber adjacent to the mineral field; boring a first tunnel into the mineral field with the tunnel boring machine, the first tunnel being laterally aligned with the initial chamber; after the tunnel boring machine bores the extent of the first tunnel, retracting the tunnel boring machine out of the first tunnel and back into the initial chamber; pouring a first grout plug ahead of the tunnel boring machine in at least a portion of a proximal end of the first tunnel; boring a second tunnel through the first grout plug into the mineral field with the tunnel boring machine, the second tunnel being laterally offset from the initial chamber, wherein: the tunnel boring machine bores the second tunnel by advancing from the initial chamber along a first S-curve path having a first curve away from the first tunnel and a second curve toward the first tunnel; and after traveling along the first S-curve path, the tunnel boring machine is advanced parallel to the first tunnel to the extent of the second tunnel; after the tunnel boring machine bores the extent of the second tunnel, retracting the tunnel boring machine out of the second tunnel and back into the initial chamber; pouring a second grout plug ahead of the tunnel boring machine in at least a portion of a proximal end of the second tunnel; boring a third tunnel through the second grout plug into the mineral field with the tunnel boring machine, the third tunnel being laterally offset from the initial chamber on an opposite side of the first tunnel from the second tunnel, wherein: the tunnel boring machine bores the third tunnel by advancing from the initial chamber along a second S-curve path having a first curve away from the first tunnel and a second curve toward the first tunnel; and after traveling along the second S-curve path, the tunnel boring machine is advanced parallel to the first tunnel to the extent of the third tunnel; and after the tunnel boring machine bores the extent of the third tunnel, retracting the tunnel boring machine out of the third tunnel and back into the initial chamber, wherein during the boring of the first, second, and third tunnels, muck produced from the boring containing the mineral ore is transported away from the respective tunnel and through the initial chamber.

14. The method of claim 13, further comprising: after the tunnel boring machine is retracted out of the third tunnel and back into the initial chamber, pouring a third grout plug ahead of the tunnel boring machine in at least a portion of a proximal end of the third tunnel; boring a fourth tunnel through the third grout plug into the mineral field with the tunnel boring machine, the fourth tunnel being laterally offset from the initial chamber on an opposite side of the second tunnel from the first tunnel, wherein: the tunnel boring machine bores the fourth tunnel by advancing from the initial chamber along a third S-curve path having a first curve away from the first and second tunnels and a second curve toward the first and second tunnels; after traveling along the third S-curve path, the tunnel boring machine is advanced parallel to the first and second tunnels to the extent of the fourth tunnel; and during the boring of the fourth tunnel, muck produced from the boring containing the mineral ore is transported away from the fourth tunnel and through the initial chamber; and after the tunnel boring machine bores the extent of the fourth tunnel, retracting the tunnel boring machine out of the fourth tunnel and back into the initial chamber.

15. The method of claim 14, further comprising: after the tunnel boring machine is retracted out of the fourth tunnel and back into the initial chamber, pouring a fourth grout plug ahead of the tunnel boring machine in at least a portion of a proximal end of the fourth tunnel; boring a fifth tunnel through the fourth grout plug into the mineral field with the tunnel boring machine, the fifth tunnel being laterally offset from the initial chamber on an opposite side of the third tunnel from the first tunnel, wherein: the tunnel boring machine bores the fifth tunnel by advancing from the initial chamber along a fourth S-curve path having a first curve away from the first and third tunnels and a second curve toward the first and third tunnels; after traveling along the fourth S-curve path, the tunnel boring machine is advanced parallel to the first and third tunnels to the extent of the fifth tunnel; and during the boring of the fifth tunnel, muck produced from the boring containing the mineral ore is transported away from the fifth tunnel and through the initial chamber; and after the tunnel boring machine bores the extent of the fifth tunnel, retracting the tunnel boring machine out of the fifth tunnel and back into the initial chamber.

16. The method of claim 13, wherein the first, second, and third tunnels are bored at a first mining tunnel layer at a first height above the initial chamber, and wherein the method further comprises: pouring a third grout plug ahead of the tunnel boring machine in at least a portion of a proximal end of the third tunnel; boring a fourth tunnel into the mineral field with the tunnel boring machine, the fourth tunnel being laterally aligned with the initial chamber; after the tunnel boring machine bores the extent of the fourth tunnel, retracting the tunnel boring machine out of the fourth tunnel and back into the initial chamber; pouring a fourth grout plug ahead of the tunnel boring machine in at least a portion of a proximal end of the fourth tunnel; boring a fifth tunnel through the fourth grout plug into the mineral field with the tunnel boring machine, the fifth tunnel being laterally offset from the initial chamber, wherein: the tunnel boring machine bores the fifth tunnel by advancing from the initial chamber along a third S-curve path having a first curve away from the fourth tunnel and a second curve toward the fourth tunnel; and after traveling along the third S-curve path, the tunnel boring machine is advanced parallel to the fourth tunnel to the extent of the fifth tunnel; after the tunnel boring machine bores the extent of the fifth tunnel, retracting the tunnel boring machine out of the fifth tunnel and back into the initial chamber; pouring a fifth grout plug ahead of the tunnel boring machine in at least a portion of a proximal end of the fifth tunnel; boring a sixth tunnel through the fifth grout plug into the mineral field with the tunnel boring machine, the sixth tunnel being laterally offset from the initial chamber on an opposite side of the fourth tunnel from the fifth tunnel, wherein: the tunnel boring machine bores the sixth tunnel by advancing from the initial chamber along a fourth S-curve path having a first curve away from the fourth tunnel and a second curve toward the fourth tunnel; and after traveling along the fourth S-curve path, the tunnel boring machine is advanced parallel to the fourth tunnel to the extent of the sixth tunnel; and after the tunnel boring machine bores the extent of the sixth tunnel, retracting the tunnel boring machine out of the sixth tunnel and back into the initial chamber, wherein during the boring of the fourth, fifth, and sixth tunnels, muck produced from the boring containing the mineral ore is transported away from the respective tunnel and through the initial chamber, and wherein the fourth, fifth, and sixth tunnels are bored at a second mining tunnel layer at a second height above the initial chamber lower than the first height.

17. The method of claim 16, further comprising: pouring a sixth grout plug ahead of the tunnel boring machine in at least a portion of a proximal end of the sixth tunnel boring a seventh tunnel into the mineral field with the tunnel boring machine, the seventh tunnel being laterally aligned with the initial chamber; after the tunnel boring machine bores the extent of the seventh tunnel, retracting the tunnel boring machine out of the seventh tunnel and back into the initial chamber; pouring a seventh grout plug ahead of the tunnel boring machine in at least a portion of a proximal end of the seventh tunnel; boring an eighth tunnel through the seventh grout plug into the mineral field with the tunnel boring machine, the eighth tunnel being laterally offset from the initial chamber, wherein: the tunnel boring machine bores the eighth tunnel by advancing from the initial chamber along a fifth S-curve path having a first curve away from the seventh tunnel and a second curve toward the seventh tunnel; and after traveling along the fifth S-curve path, the tunnel boring machine is advanced parallel to the seventh tunnel to the extent of the eighth tunnel; after the tunnel boring machine bores the extent of the eighth tunnel, retracting the tunnel boring machine out of the eighth tunnel and back into the initial chamber; pouring an eighth grout plug ahead of the tunnel boring machine in at least a portion of a proximal end of the eighth tunnel; boring a ninth tunnel through the eighth grout plug into the mineral field with the tunnel boring machine, the ninth tunnel being laterally offset from the initial chamber on an opposite side of the seventh tunnel from the eighth tunnel, wherein: the tunnel boring machine bores the ninth tunnel by advancing from the initial chamber along a sixth S-curve path having a first curve away from the seventh tunnel and a second curve toward the seventh tunnel; and after traveling along the sixth S-curve path, the tunnel boring machine is advanced parallel to the seventh tunnel to the extent of the ninth tunnel; and after the tunnel boring machine bores the extent of the ninth tunnel, retracting the tunnel boring machine out of the ninth tunnel and back into the initial chamber, wherein during the boring of the seventh, eighth, and ninth tunnels, muck produced from the boring containing the mineral ore is transported away from the respective tunnel and through the initial chamber, and wherein the seventh, eighth, and ninth tunnels are bored at a third mining tunnel layer at a third height above the initial chamber lower than the first and second heights.

18. The method of claim 16, wherein the proximal position of the first, second, and third tunnels is further from the initial chamber than the proximal position of the fourth, fifth, sixth, seventh, eighth, and ninth tunnels.

19. The method of claim 17, wherein the proximal position of the fourth, fifth, and sixth tunnels is further from the initial chamber than the proximal position of the seventh, eighth, and ninth tunnels.

Description

DESCRIPTION OF THE DRAWINGS

[0005] The foregoing aspects and many of the attendant advantages of the claimed subject matter will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:

[0006] FIG. 1 is a schematic view of an embodiment of mining tunnels excavated with a tunnel boring machine (TBM), in accordance with methods of the present disclosure;

[0007] FIGS. 2A-2C are schematic views of the mining tunnels of FIG. 1, with the representative portion of a grout plug disposed in a tunnel;

[0008] FIG. 3 is a series of schematic views of steps of a method of excavating the mining tunnels of FIG. 1 with a TBM;

[0009] FIGS. 4 and 5 are cross section views of an embodiment of mining tunnels excavated with a TBM, in accordance with methods of the present disclosure;

[0010] FIG. 6A is a cross-section view and FIG. 6B is a detail view of an embodiment of mining tunnels excavated with a TBM using a benching operation, in accordance with methods of the present disclosure;

[0011] FIGS. 7-9 are cross-section views of an embodiment of mining tunnels excavated with a TBM, in accordance with methods of the present disclosure;

[0012] FIGS. 10A-10C are perspective views of layers of mining tunnels excavated with a TBM, in accordance with methods of the present disclosure, with FIG. 10A showing a first mining tunnel layer, FIG. 10B showing first and second mining tunnel layers, and FIG. 10C showing first, second, and third mining tunnel layers; and

[0013] FIG. 11 is a schematic view of a plurality of mining tunnel systems excavated with a TBM, in accordance with methods of the present disclosure.

DETAILED DESCRIPTION

[0014] The detailed description set forth herein connection with the appended drawings, where like numerals reference like elements, are intended as a description of various embodiments of the present disclosure and are not intended to represent the only embodiments. Each embodiment described in this disclosure is provided merely as an example or illustration and should not be construed as preferred or advantageous over other embodiments. The illustrative examples provided herein are not intended to be exhaustive or to limit the disclosure to the precise forms disclosed.

[0015] As will be described in more detail below, the present disclosure provides examples of methods for underground mining using one or more tunnel boring machines (TBMs). TBMs provide an alternative to drilling and blasting methods for excavating mining tunnels though a variety of rock strata. TBMs are generally capable of efficiently excavating elongate tunnels through hard materials, and have the capacity to operate at relatively fast advance rates, resulting in high productivity. Moreover, TBMs efficiently fracture or otherwise break up the target bored materials into useful particle sizes for downstream mining operations. Conventional TBMs have not been considered suitable for tunnel mining based on their relatively long assemblies and lack of agility; however, the methods of the present disclosure are expected to address these and other drawbacks.

[0016] In an example of a method in accordance with the present disclosure, an underground chamber is constructed near a deposit of the desired mineral ore to be mined (the mineral field). The initial chamber can be excavated using conventional or TBM methods, and can be sized and configured to receive a TBM, related support components, and a muck removal system. TBMs typically include a rotating cutting wheel (cutter head), a main bearing, a thrust system, and trailing support mechanisms. For hard rock boring, disc cutters are rotatably mounted in the cutter head and projected forwardly, such that the disc cutters are pressed against the rock face with force sufficient to create compressive stress fractures in the rock face. The fractured rock fragments (muck) are then transferred to a conveyor and through the TBM for removal, for example, by a conveyor system trailing the TBM. In some open type, or main beam TBMs, hydraulic jacks extend from the TBM to engage and press against tunnel walls, and propel cylinders of the system urge the rotating cutter head against the rock surface for a cycle. The hydraulic jacks are then retracted to disengage, and the TBM is moved forward, after which the cycle is repeated. After the TBM and conveyor system are assembled in the initial chamber, the TBM begins driving forward to excavate a first production tunnel outside of the chamber. During this excavation, the TBM muck, which can contain the mined material from the mineral field, can be conveyed back to the chamber for removal, e.g., through a shaft extending from the surface ground into the chamber. The muck can be processed further after removal, such as separation of the desired mineral ore from other materials, further breaking of the material, etc.

[0017] In accordance with one aspect of the method of the present disclosure, the TBM progresses forward into the first production tunnel to extract the target materials (the excavated minerals). When the desired length or distal extent of the first tunnel is reached, the TBM and related support equipment are retracted by backing up the TBM to a desired starting position in the initial chamber for a second pass through the mineral field. After the TBM is retracted, a plug, e.g., a grout plug, can be poured or otherwise installed in a proximal end portion of the first production tunnel to ensure integrity of the mining region during further operations. Next, the TBM can be positioned to a desired starting point to engage the grout plug and the hydraulic system is operated to urge the TBM along an S-curved path to avoid overlap with the first production tunnel and then straightened out to excavate a second tunnel generally parallel to the first tunnel along at least a portion of the length of the second tunnel. The parallel portion of the second tunnel is spaced sufficiently from the first tunnel such that a wall between the first tunnel and the second tunnel retains its integrity. These steps may be repeated to excavate materials from a plurality of further tunnels through the target region.

[0018] As will be described in greater detail below with reference to the FIGURES the tunnels may be excavated at different elevations. For example, in an embodiment, a first layer of tunnels can be excavated generally across a first elevation, with the tunnels being relatively closely spaced. The first layer of tunnels can be positioned at a lower elevation than a second layer of tunnels excavated generally across a second, higher elevation. In some embodiments, the first and second layers can be at least partially interleaved at different elevations within the layers to reduce the amount of ground substrate between the tunnel layers, e.g., to excavate the highest percentage of the target minerals in a given cross-sectional area. In the methods disclosed herein, the sets of tunnels can be spaced apart sufficiently to retain the integrity of the target region during mining operations.

[0019] Although embodiments of the present disclosure may be described with reference to methods of using a TBM for extracting ore during mining operations, including the configurations shown in the FIGURES, one skilled in the relevant art will appreciate that the disclosed embodiments are illustrative in nature and therefore should not be construed as limited to such an application. It should therefore be apparent that the disclosed technologies and methodologies have wide application, and therefore may be suitable for use with many types of applications. Accordingly, the following descriptions and illustrations herein should not limit the scope of the claimed subject matter.

[0020] FIG. 1 is a schematic view of an embodiment of mining tunnels 100 excavated with a tunnel boring machine TBM, in accordance with methods of the present disclosure. The mining tunnels 100 can include a service shaft 102 and a production shaft 104, both leading into a service chamber 110 therebetween, and an initial chamber 112 in which the TBM is staged for additional assembly and mining operations during excavation of the tunnels. The service shaft 102 can be used to, e.g., provide access for personnel, equipment, materials, etc. into the service chamber 110 and/or the initial chamber 112, and the production shaft 104 can be used, e.g., to provide access for muck removal during the excavation of the tunnels by the TBM. The service shaft 102 and the production shaft 104 can have any suitable diameter necessary for transport of the equipment, personnel, materials, muck, etc., and in some embodiments the diameter of the shafts 102 and 104 can be from about 5 m to 10 m, from about 6 m to 8 m, or about 6.75 m. As shown, the shafts 102 and 104 can be spaced at a distance D1 to provide adequate spacing between the shafts for mining operations. In some embodiments, the distance D1 can be about 100 m. FIG. 1 is shown without the TBM for clarity in the figure, but will be shown with reference to FIG. 3.

[0021] As shown in the illustrated embodiment, the initial chamber 112 can have a distance D2 suitable for staging and assembly of the TBM, including the rotating cutting wheel (cutter head), main bearing, thrust system, splice, cassette, and trailing support mechanisms of the TBM, including a muck conveyor system CON (see FIG. 3). In this regard, the distance D2 can be the same as a pillar radius R2 between the production shaft 104 and the proximal end of the plurality of mining tunnels 114. In some embodiments, the distance D2 can be about 400 m; however, any suitable distance D2 is within the scope of the present disclosure. The mining tunnels 114 are shown with an indeterminate length D3 in FIG. 1 for purposes of illustration; however, an exemplary scaled length D3 with respect to lengths D1 and D2 is shown in FIG. 2A. In some embodiments, the length D3 can be any suitable length dependent on the material field, the length of the TBM, the length of the TBM trailing equipment, etc. In an example, the length D3 can be from about 1500 m to 3000 m or greater.

[0022] The mining tunnels 114 can include a first tunnel T1, a second tunnel T2, a third tunnel T3, a fourth tunnel T4, and a fifth tunnel T5. The illustrated embodiment shows five tunnels as an example, but further tunnels are within the scope of the methods of the present disclosure (see, e.g., FIG. 11). The first tunnel T1 is shown as a linear tunnel aligned with the initial chamber 112 and the service chamber 110, while the other tunnels T2-T5 are shown laterally spaced from the first tunnel T1 with curved portions having a radius R2, with curves between a distance D4. Some embodiments the radius R2 of the curved portions can be the smallest cornering radius of the TBM, e.g., less than 500 m, from about 200 m to 500 m, or about 300 m. The distance D4 can vary based on the number of tunnels in a tunnel layer, for example, increasing in length for a greater number of tunnels, and decreasing in length for a smaller number of tunnels. In embodiments with five tunnels, such as the illustrated embodiment, the distance D4 can be about 180 m.

[0023] FIGS. 2A-2C are schematic views of the mining tunnels 114, with a representative portion of a first grout plug 120 disposed in the first tunnel T1 as shown in FIG. 2B, which shows a detail view of the area generally corresponding to the curved portions of the tunnels T1-T5, as noted on FIG. 2A. The first grout plug 120 can be poured in the first tunnel T1 after excavation of the first tunnel T1, before excavation of the remaining tunnels T2-T5, as will be described in greater detail with respect to FIG. 3. As shown, the first grout plug 120 can have a length D7 corresponding to a length at which a minimum lateral distance D6 between the first tunnel T1 and the second tunnel T2 is wide enough for structural integrity between the lateral tunnels. For example, for a TBM capable of excavating tunnels of about 7 m, the minimum lateral distance D6 between the first grout plug 120 and the second tunnel T2 can be about 3 m; however, other lateral distances may be required based on the material of the substrate in the mineral field. In this example, the length D7 of the first grout plug 120 can be about 80 m. The first grout plug 120 provides structural integrity of the mining tunnels 114 during drilling of the second tunnel T2, and permits the turning of the TBM around the curved path. In absence of the grout plug, the TBM would naturally follow down the first tunnel T1 instead of curving into the path to form the second tunnel T2.

[0024] FIG. 2C shows a detail cross-section of tunnels T1-T3 at a distance D5 from the proximal end of the first grout plug 120. As shown, the tunnels T1-T3 can have a bore diameter BD, in this example of about 7 m, and can have a lateral tunnel spacing D8 forming a pillar between the tunnels. In some embodiments, the lateral tunnel spacing D8 at the distance D5 (about 75 m) can be about 2.1 m. In the illustrated embodiment, the first grout plug 120 can have an extent height D9 above the central axis of the bore of the tunnel, with a height sufficient to permit drilling of the lateral tunnels T2 and T3. In some embodiments, the extent height D9 is about 2 m.

[0025] FIG. 3 is a series of schematic views of steps of a method of excavating mineral ore from the mining tunnels 114 with a TBM. In a first step 10, the TBM bores the first tunnel T1 by advancing from the initial chamber 112 and down the length D3 of the first tunnel T1, while the muck is transported along the muck conveyor system CON rearward through the initial chamber 112 to the production shaft 104 for removal. As noted above, the length D3 can be from about 1500 m to 3000 m or greater. After the TBM bores the extent of the first tunnel T1, in a second step 20, the TBM is retracted out of the first tunnel T1 by backing up into the initial chamber 112 to a position such that the first grout plug 120 can be poured along the distance D7 (FIG. 2B) in front of the TBM. Advancing to a third step 30, the TBM bores the second tunnel T2 by advancing from the initial chamber 112 along an S-curve path first at the radius R2 to the left of the first tunnel T1, and then at the radius R2 to the right to a direction parallel to the path of the first tunnel T1. The boring of the second tunnel T2 partially bores through the first grout plug 120. As with the first tunnel T1, the muck from the second tunnel T2 is transported along the muck conveyor system CON rearward through the initial chamber 112 to the production shaft 104 for removal.

[0026] After the TBM boards the extent of the second tunnel T2, in a fourth step 40, the TBM is retracted out of the second tunnel T2 by backing up into the initial chamber 112 to a position such that a second grout plug 122 can be poured in front of the TBM. Advancing to a fifth step 50, the TBM bores the third tunnel T3 by advancing from the initial chamber 112 along an S-curve path first at the radius R2 to the right of the first tunnel T1, and then at the radius R2 to the left to a direction parallel to the path of the first tunnel T1. The boring of the third tunnel T3 partially bores through the second grout plug 122. As with the first and second tunnels T1 and T2, the muck from the third tunnel T3 is transported along the muck conveyor system CON rearward through the initial chamber 112 to the production shaft 104 for removal.

[0027] After the TBM boards the extent of the third tunnel T3, in a six step 60, the TBM is retracted out of the third tunnel T3 by backing up into the initial chamber 112 to a position such that a third grout plug 124 can be poured in front of the TBM. Advancing to a seven step 70, the TBM bores the fourth tunnel T4 by advancing from the initial chamber 112 along an S-curve path first at the radius R2 to the left of the second tunnel T2, and then at the radius R2 to the right to a direction parallel to the path of the first and second tunnels T1 and T2. The boring of the fourth tunnel T4 partially bores through the third grout plug 124. As with the first and second tunnels T1 and T2, the muck from the fourth tunnel T4 is transported along the muck conveyor system CON rearward through the initial chamber 112 to the production shaft 104 for removal.

[0028] After the TBM boards the extent of the second tunnel T4, in an eight step 80, the TBM is retracted out of the fourth tunnel T4 by backing up into the initial chamber 112 to a position such that a fourth grout plug 126 can be poured in front of the TBM. Advancing to a night step 90, the TBM bores the fifth tunnel T5 by advancing from the initial chamber 112 along an S-curve path first at the radius R2 to the right of the third tunnel T3, and then at the radius R2 to the left to a direction parallel to the path of the first and third tunnels T1 and T3. The boring of the fifth tunnel T5 partially bores through the fourth grout plug 126. As with the first and third tunnels T1 and T3, the muck from the fifth tunnel T5 is transported along the muck conveyor system CON rearward through the initial chamber 112 to the production shaft 104 for removal.

[0029] FIGS. 4 and 5 are cross section views of another embodiment of mining tunnel levels 130, 132, 134, and 136 excavated with the TBM, in accordance with methods of the present disclosure. As shown in FIG. 4, in the mining tunnels levels 130 and 132, the tunnels are interleaved at different elevations within the levels 130 and 132, for example, at a vertical height between the center of the tunnels in each level of about 4 m with a full height extent of the level being about 11 m, results in a spacing between the tunnels within a level of about 1.06 m. In this regard, the lateral spacing of the center of each tunnel in the level is about 7 m. The height extent of the level of 11 m and the width of a tunnel pair being about 14 m gives a material substrate area of about 154 m.sup.2 with a mined area of the bores of the tunnel pair of about 77 m.sup.2 for a recovery percentage of 50%. As shown in FIG. 5, in the mining tunnels levels 134 and 136, the tunnels are interleaved at different elevations within the levels 134 and 136, but to a wider extent than the levels 130 and 132 of FIG. 4. For example, at a vertical height between the center of the tunnels in each level of about 4 m with a full height extent of the level being about 11 m, results in a spacing between the tunnels within a level of about 3.77 m. In this regard, the lateral spacing of the center of each tunnel in the level is about 10 m. The height extent of the level of 11 m and the width of a tunnel pair being about 20 m gives a material substrate area of about 220 m.sup.2 with a mined area of the bores of the tunnel pair of about 77 m.sup.2 for a recovery percentage of 35%.

[0030] FIG. 6A is a cross-section view and FIG. 6B is a detail view of an embodiment of mining tunnel levels 140 and 142 excavated with the TBM using a benching operation, in accordance with methods of the present disclosure. As shown in FIG. 6A, in the mining tunnels levels 140 and 142, the tunnels are benched (aligned vertically with at least a portion of the vertical tunnel pairs overlapping) at different elevations within the levels 140 and 142, for example, at a vertical height between the center of the tunnels within each level of about 4 m with a full height extent of the level being about 11 m. In this regard, each tunnel pair, e.g., a first vertically aligned tunnel T1a and a second vertically aligned tunnel T1b, having a spacing between an adjacent vertically aligned tunnel pair of about 3 m. The height extent of the level of 11 m and the width of the tunnel pair being about 7 m with adjacent vertically aligned tunnel pair spacing of 3 m gives a material substrate area of about 110 m.sup.2 with a mined area of the bores of the tunnel pair of about 64.9 m.sup.2 for a recovery percentage of 59%. In this example, the full bore T1a has a mined area of 38.5 m.sup.2 and the lower benched bore T1b has a mined area of 26.4 m.sup.2. FIG. 6B shows the TBM in the benched bore T1b.

[0031] In an example, FIG. 7 shows an embodiment of a benching operation 200 of mining tunnel layout which permits recovery percentages similar to conventional chamber and pillar mining operations (in some examples, about 55% for conventional operations). In the benching operation 200, the pillars can be about 3.7 m spacing, resulting in a recovery percentage of about 55%.

[0032] FIGS. 8 and 9 are cross-section views of an embodiment of mining tunnels 300 and 400, respectively, excavated with the TBM, in accordance with methods of the present disclosure. The layouts of the tunnels 300 and 400 are similar to the embodiments shown in FIGS. 4 and 5, with the tunnels interleaved at different elevations, but closer to each other in elevation. FIG. 8 shows the mining tunnels 300 having a 27-tunnel grid with minimum spacing between the tunnels of about 2.62 m as shown. In this configuration, the extent height of a column is about 40 m, with a width of about 14 m, having an area of about 560 m.sup.2, with a mined area of 6-tunnels of about 231 m.sup.2, resulting in a recovery percentage of about 41%. FIG. 9 shows the mining tunnels 400 having a 36-tunnel grid with minimum spacing between the tunnels of about 4.06 m as shown. In this configuration, the extent height of a column is about 40 m, with a width of about 20 m, having an area of about 800 m.sup.2, with a mined area of 8-tunnels of about 308 m.sup.2, resulting in a recovery percentage of about 39%.

[0033] FIGS. 10A-10C are perspective views of layers of mining tunnels T1-T14 excavated with a TBM, in accordance with methods of the present disclosure, with FIG. 10A showing a first mining tunnel layer L1 having mining tunnels T1-T5, FIG. 10B showing the first mining tunnel layer L1 and a second mining tunnel layer L2 having mining tunnels T6-T10, and FIG. 10C showing the first and second mining tunnel layers L1 and L2, and a third mining tunnel layer L3 having mining tunnels T11-T15. Referring initially to FIG. 10A, from the initial chamber 112 at a height H0, the TBM bores on a curved upward path (for example at the radius R2 of about 300 m) to a height H1 of the first mining tunnel layer L1 at which the tunnel boring operations are carried out to form the mining tunnels T1-T5 (e.g., the method shown in FIG. 3). Referring next to FIG. 10B, after the first mining tunnel layer L1 is complete, the TBM backs down to the initial chamber 112 at the height H0, and the TBM bores on a curved upward path (for example at the radius R2 of about 300 m) to a height H2 of the second mining tunnel layer L2, positioned below the first mining tunnel layer L1 at the height H1. When the TBM is positioned at the height H2, the tunnel boring operations of the second mining tunnel layer L2 are carried out to form the mining tunnels T6-T10 (e.g., the method shown in FIG. 3). Referring finally to FIG. 10C, after the first and second mining tunnel layers L1 and L2 are complete, the TBM backs down to the initial chamber 112 at the height H0, and the TBM bores at a height H3, at about the same level as H0, the third mining tunnel layer L3, positioned below the first and second mining tunnel layers L1 and L2. In the illustrated embodiment, the height H1 is higher than the heights H2 and H3, and the height H2 is higher than the height H3. When the TBM is positioned at the height H3, the tunnel boring operations of the third mining tunnel layer L3 are carried out to form the mining tunnels T11-T15 (e.g., the method shown in FIG. 3).

[0034] FIG. 11 is a schematic view of a plurality of mining tunnel systems excavated with a TBM, in accordance with methods of the present disclosure. As shown, the tunnel systems can be laterally spaced to form groups of lateral tunnels in accordance with any of the embodiments of the methods disclosed herein. For example, a first tunnel group G1 can be formed using, e.g., the method shown in FIG. 3, then a lateral second tunnel group G2, a lateral third tunnel group G3, and a lateral fourth tunnel group G4 can be similarly formed. In each of these illustrated embodiments, the tunnel groups can have any number of lateral tunnels, and can include tunnel benching (see FIG. 6A) and/or interleaved tunnels (see FIGS. 8 and 9), etc.

[0035] In the foregoing description, specific details are set forth to provide a thorough understanding of exemplary embodiments of the present disclosure. It will be apparent to one skilled in the art, however, that the embodiments disclosed herein may be practiced without embodying all of the specific details. In some instances, well-known process steps have not been described in detail in order not to unnecessarily obscure various aspects of the present disclosure. Further, it will be appreciated that embodiments of the present disclosure may employ any combination of features described herein.

[0036] The present application may reference quantities and numbers. Unless specifically stated, such quantities and numbers are not to be considered restrictive, but exemplary of the possible quantities or numbers associated with the present application. Also in this regard, the present application may use the term plurality to reference a quantity or number. In this regard, the term plurality is meant to be any number that is more than one, for example, two, three, four, five, etc. The terms about, approximately, near, etc., mean plus or minus 10% of the stated value. For the purposes of the present disclosure, the phrase at least one of A and B is equivalent to A and/or B or vice versa, namely A alone, B alone or A and B. Similarly, the phrase at least one of A, B, and C, for example, means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C), including all further possible permutations when greater than three elements are listed.

[0037] It should be noted that for purposes of this disclosure, terminology such as upper, lower, vertical, horizontal, fore, aft, inner, outer, front, rear, etc., should be construed as descriptive and not limiting the scope of the claimed subject matter. Further, the use of including, comprising, or having and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless limited otherwise, the terms connected, coupled, and mounted and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, and mountings.

[0038] Throughout this specification, terms of art may be used. These terms are to take on their ordinary meaning in the art from which they come, unless specifically defined herein or the context of their use would clearly suggest otherwise.

[0039] The principles, representative embodiments, and modes of operation of the present disclosure have been described in the foregoing description. However, aspects of the present disclosure, which are intended to be protected, are not to be construed as limited to the particular embodiments disclosed. Further, the embodiments described herein are to be regarded as illustrative rather than restrictive. It will be appreciated that variations and changes may be made by others, and equivalents employed, without departing from the spirit of the present disclosure. Accordingly, it is expressly intended that all such variations, changes, and equivalents fall within the spirit and scope of the present disclosure as claimed.