METHOD AND APPARATUS FOR USE IN STOPE BACKFILL MINING

Abstract

A method for forming a passage in stope backfill material includes steps of: a) providing an expandable void forming apparatus at a lower level relative to an unexcavated stope; b) expanding the void forming apparatus, such that a substantially liquid-impermeable seal is formed between the void forming apparatus and the unexcavated stope; c) pouring backfill material into a void formed by the excavation of a stope adjacent to the unexcavated stope, and allowing the backfill material to at least partially cure such that the void forming apparatus forms a passage between the unexcavated stope and the backfill material; and d) contracting the void forming apparatus and removing the void forming apparatus from the passage.

Claims

1. A method for forming a passage in stope backfill material, the method comprising the steps of: a) providing an expandable void forming apparatus at a lower level relative to an unexcavated stope; b) expanding the void forming apparatus, such that a substantially liquid-impermeable seal is formed between the void forming apparatus and the unexcavated stope; c) pouring backfill material into a void formed by the excavation of a stope adjacent to the unexcavated stope, and allowing the backfill material to at least partially cure such that the void forming apparatus forms a passage between the unexcavated stope and the backfill material; and d) contracting the void forming apparatus and removing the void forming apparatus from the passage.

2. A method according to claim 1, wherein the void forming apparatus is expandable between a contracted condition and an expanded condition.

3. A method according to claim 1, wherein the void forming apparatus is located in a passage located substantially beneath or adjacent the unexcavated stope.

4. A method according to claim 1, wherein the void forming apparatus is formed from one or more void forming nodules configured for connection to one another.

5. A method according to claim 1, wherein the void forming apparatus is at least partially fabricated from one or more inflatable members.

6. A method according to claim 5, wherein the one or more inflatable members are provided in a form of one or more inflatable bladders or balloons.

7. A method according to claim 5, wherein the one or more inflatable members are located within one or more outer layers of flexible material.

8. A method according to claim 5, wherein the one or more inflatable members are associated with a source of inflating fluid.

9. A method according to claim 8, wherein the inflating fluid comprises a relatively inert gas.

10. A method according to claim 1, wherein the void forming apparatus comprises one or more skirt members configured to form a substantially liquid impermeable seal between a ground surface and the void forming apparatus.

11. A method for forming a slot void in stope backfill material, the method comprising the steps of: a) providing an expandable barrier member configured to extend upwardly from or adjacent a lower level relative to an unexcavated towards an upper level relative to the unexcavated stope, b) expanding the barrier member, such that a substantially liquid-impermeable seal is formed between the barrier and the unexcavated stope; c) pouring backfill material into a void formed by the excavation of a stope adjacent to the unexcavated stope, and allowing the backfill material to at least partially cure such that the barrier member forms a slot void between the unexcavated stope and the backfill material; and d) contracting the barrier member and removing the barrier member from the slot void.

12. A method according to claim 11, wherein the expandable barrier member is substantially elongate in shape.

13. A method according to claim 11, wherein the barrier member is fabricated from one or more elongate inflatable members.

14. A method according to claim 13, wherein the one or more elongate inflatable members are located within one or more outer layers of flexible material.

15. A method according to claim 11, wherein the barrier member is positioned in abutment with a substantially vertical edge of the unexcavated slope along at least a portion of the height of the substantially vertical edge of the unexcavated stope.

16. A method according to claim 11, wherein the barrier member extends to at least a level of a passage located substantially above or adjacent the unexcavated stope.

17. A method according to claim 11, wherein one or more sensors are associated with the barrier member, the one or more sensors being configured to measure the location of the barrier member within the void and/or the pressure in the barrier member.

18. A void forming apparatus for forming a void in stope backfill material, the apparatus comprising: an inflatable member; an outer layer at least partially surrounding the inflatable member; and wherein the inflatable member is inflatable between a contracted condition and an expanded condition in which the void forming apparatus forms a substantially continuous void forming surface.

19. A void forming apparatus according to claim 18, wherein the inflatable member and the outer layer are at least partially fabricated from PVC.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0088] Preferred features, embodiments and variations of the invention may be discerned from the following Detailed Description which provides sufficient information for those skilled in the art to perform the invention. The Detailed Description is not to be regarded as limiting the scope of the preceding Summary of Invention in any way. The Detailed Description will make reference to a number of drawings as follows:

[0089] FIG. 1 illustrates an exploded view of a void forming apparatus according to an embodiment of the present invention.

[0090] FIGS. 2-5 illustrate steps in method for forming a passage and/or slot void in stope backfill material according to various embodiments of the present invention.

DETAILED DESCRIPTION

[0091] FIG. 1 illustrates an exploded view of a void forming apparatus 10 according to an embodiment of the present invention. The void forming apparatus 10 comprises an inflatable member 11 that is inflatable between a contracted condition and the expanded condition shown in FIG. 1. The inflatable member 11 includes a pair of connection members 12 through which inflating fluid enters and exist the inflatable member 11 so as to inflate and deflate the inflatable member 11. The connection members 12 are associated with conduits 13 that are used to interconnect the connection members 12 with hoses or the like associated with the source of the inflating fluid. Pressure relief valves 14 are associated with the connection members in order to prevent overinflation of the inflatable member 11.

[0092] The void forming apparatus further comprises an outer layer 15 that, in use, houses the inflatable member 11 therewithin. The outer layer 15 is of approximately the same size and shape as the inflatable member 11 when the inflatable member is in the expanded condition. In this way, the material of the outer layer 15 may be stretched relatively taut by the expanded inflatable member 11 so as to create a relatively uniform seal between the void forming apparatus 10 and the surface of the unexcavated stope (not shown) in which the apparatus 10 is used.

[0093] The outer layer 15 is formed from a plurality of surface portions such that the outer layer 15 comprises two pairs of side walls and an upper surface 16. In use, the outer layer 15 forms the void forming surface, and the passage formed within the backfill material will have substantially the same shape and size as the outer layer 15. In the embodiment of the invention shown in FIG. 2, the upper surface 16 is curved such that the passage formed within the backfill material will have an arched shape.

[0094] The outer layer 15 further comprises a skirt member 17 that extends outwardly from a lower region of the outer layer 15. The skirt member 17 is positioned at approximately 90 to the side walls of the outer layer 15 and is configured to be located in abutment with a ground surface in in the passageway in which the void forming apparatus 10 is to be used. By locating the skirt member 17 in abutment with the ground surface, the flow of backfill material between the ground surface and the skirt member 17 may be reduced or eliminated.

[0095] The skirt member 17 extends only partway about the periphery of the outer layer 15, and it is envisaged that the skirt member 17 will be located at the end of the apparatus 10 closest to the point at which backfill material enters the void formed by the excavation of an adjacent stope.

[0096] The outer layer 15 is provided with a plurality of apertures 18 therein. In use, the connection members 12 and/or the conduits 13 pass at least partially through the apertures 18 to allow connection to the source of the inflating fluid while still ensuring that the inflatable member 11 remains housed within the outer layer 15.

[0097] The void forming apparatus 10 further comprises a sealing member 19 in the form of a ring that surrounds the apparatus 10 and extends along a portion of the length of the apparatus 10. The sealing member 19 of FIG. 1 is fabricated from a foamed polymeric material such that, in use, the sealing member forms a seal against the surface of the unexcavated stope (not shown) in which the apparatus 10 is used.

[0098] In FIG. 2, the void forming apparatus 10 is shown in use. The apparatus 10 is positioned within a passageway 20 formed beneath an unexcavated stope 21. The apparatus 10 is shown in the expanded condition in which the outer layer 15 and/or the sealing member 19 form a substantially liquid-impermeable seal against the unexcavated stope 21. Thus, it is envisaged that the flow of backfill material between the outer layer 15 and/or the sealing member 19 may be reduced or eliminated.

[0099] In FIG. 2, it may also be seen that the upper surface 16 of the outer layer is provided with a plurality of lifting members 22 to facilitate lifting of the apparatus 10 for transportation or to be placed into storage.

[0100] When positioning the apparatus within the passageway 20, a portion of the apparatus 10 extends beyond the edge 23 of the unexcavated stope 21 and into a void 24 formed by the excavation of an adjacent stope. Once the apparatus 10 is in place, backfill material (not shown) may be poured into the void 24.

[0101] In FIG. 3, an inflatable barrier member 25 extends upwardly from the void forming apparatus 10 to an upper passageway 26 above the unexcavated stope 21. The inflatable barrier member is positioned against a vertical edge 32 of the unexcavated stope 21. Both the void forming apparatus 10 and the inflatable barrier member 25 of FIG. 3 are shown in their expanded conditions.

[0102] Backfill material 27 is poured into the void adjacent the unexcavated stope 21 from the upper passageway 26. The backfill material 27 flows partially about the barrier member 25 and along the void forming surface (formed by the outer layer 15 of the void forming apparatus 10). While it is envisaged that the seal formed between the outer layer 15 and the unexcavated stope 21 may be sufficient to substantially prevent backfill material 27 from passing therebetween, it is envisaged that, in any event, backfill material 27 may pass between the outer layer 15 and the unexcavated stope 21 only as far as the sealing member 19. The backfill material 27 is poured into the void until the level of the backfill material 27 in the void reaches the floor level of the upper passageway 26. The backfill material is then allowed to at least partially cure.

[0103] Once the backfill material 21 has at least partially cured, the void forming apparatus 10 and the barrier member 25 are removed as shown in FIG. 4. The barrier member 25 is deflated and then removed via the upper passageway 26. The void forming apparatus 10 is moved from the expanded condition to the retracted condition so that it can be removed from the passageway 20. In FIG. 4, the void forming apparatus 10 is mounted on wheels 28, so that the void forming apparatus 10 may be wheeled out of the passageway 20.

[0104] Removal of the void forming apparatus 10 leaves a passage 29 formed in the cured backfill material 27 that joins the passageway 20 beneath the unexcavated stope 21, while removal of the barrier member 25 leaves a substantially vertical slot void 30 between the backfill material 27 and the unexcavated stope 21 that extends between the lower passageway 20 and the upper passageway 26.

[0105] In FIG. 5, mining of the unexcavated stope 21 can now begin. A drilling machine 31 enters the lower passageway 20 and can immediately begin to drill boreholes into the unexcavated stope 21 along the vertical edge 32 thereof via the slot void 30 without needing to first drill or mine a slot void from the backfill material 27.

[0106] The passage 29 (which in this Figure extends partially beneath the unexcavated stope 21) formed by the void forming apparatus (not shown in this Figure) also provides a stable roof over the drilling machine 31 as it forms drillholes in the unexcavated stope 21.

[0107] By eliminating the requirement to drill or mine the cured backfill material to create a passage and/or void slot in the backfill material, the present invention allows drilling or mining of the unexcavated scope to begin as soon as the backfill material has cured to a sufficient degree. Not only does this reduce the time taken to ready the unexcavated stope for mining (thereby reducing production downtime), but it also reduces the quantity (and therefore cost) of backfill material required to fill the void. In addition, the present invention reduces equipment wear and associated maintenance costs by reducing or eliminating the requirement to drill or mine a passage and/or slot void in the backfill material. Finally, the present invention reduces or eliminates the possibility of damage to equipment or injury to workers when drilling or mining backfill material to form a passage and/or slot void therein.

[0108] In the present specification and claims (if any), the word comprising and its derivatives including comprises and comprise include each of the stated integers but does not exclude the inclusion of one or more further integers.

[0109] Reference throughout this specification to one embodiment or an embodiment means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases in one embodiment or in an embodiment in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.

[0110] In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims (if any) appropriately interpreted by those skilled in the art.