Open well assisted mining method for metal surface mine bottom boundary isolation pillars

Abstract

The invention relates to the technical field of mining, in particular to an open well assisted mining method for metal surface mine bottom boundary isolation pillars, which comprises the following steps: S1, stope division: arranging a stope at an open pit bottom according to a two-step stoping mode; s2, mining preparation engineering arrangement: arranging a plurality of rock drilling drift on the footwall of the ore body along the trend of the ore body; s3, cutting engineering arrangement: arranging a cutting groove and a cutting well in the stope; s4, stoping: a downward large-diameter deep hole is formed in the bottom of the open pit, and an upward fan-shaped medium-length hole is formed in the top of the rock drilling gate way; s5, a filling pipeline is arranged at the bottom of the open pit; and S6, filling, wherein filling is conducted in time after the two-step stoping mode is finished. According to the method, the ore body is stoped by combining a two-step stoping mode with an open well assisted mining mode, so that the ore body stoping efficiency is effectively improved; the mining method can be effectively suitable for mining the open pit bottom boundary isolation pillar gently inclined ore body, and the recovery amount of mine resources can be effectively increased.

Description

Technical Field

[0001] The invention relates to the technical field of mining, in particular to an open-pit mine coordinated mining method for a boundary isolation pillar at the bottom of a metal open-pit mine. Background Art

[0002] When mining is switched from open pit to underground mining, open pit boundary isolation pillars need to be set up during joint open pit and underground mining to ensure the safety of open pit and underground production operations. However, the setting of the pillars causes a waste of mineral resources in the mine. In order to improve resource utilization, boundary isolation pillars should be recovered in a timely manner after the end of open pit mining.

[0003] In terms of open-pit boundary isolation pillar mining, there is currently little research on boundary isolation pillar mining at home and abroad, and it mainly focuses on inclined and steeply inclined ore bodies. There is currently no relatively complete mining method for gently inclined ore bodies. The safe and efficient mining of gently inclined boundary isolation pillars has become one of the urgent problems to be solved in open-pit to underground mining mines.

[0004] Therefore, there is an urgent need for an open-pit and underground coordinated mining method for the bottom boundary isolation pillars of metal open-pit mines. By adopting the method of coordinated open-pit and underground mining, it can be effectively applied to the mining of gently inclined ore bodies with boundary isolation pillars at the bottom of open-pit pits; at the same time, for ore bodies exposed on the surface or with thin overlying rock layers that can be stripped in the open air, the method of using open-pit downward holes and pulling the ore out from the bottom of the pit to recover the ore can not only effectively improve the efficiency of ore recovery, but also effectively increase the amount of mine resource recovery. Summary of the invention

[0005] The purpose of the present invention is to provide a method for co-mining open-pit mines with isolation pillars at the bottom of a metal open-pit mine, so as to solve the problems existing in the above-mentioned prior art.

[0006] To achieve the above object, the present invention provides the following scheme: a method for mining open-pit mines with a bottom boundary isolation pillar in a metal open-pit mine, comprising the following steps:

[0007] S1. Stope division: Arrange the stopes at the bottom of the open pit according to the two-step mining method;

[0008] S2. Mining project layout: Arrange several rock drilling tunnels along the ore body strike in the footwall of the ore body;

[0009] S3. Cutting engineering layout: Arrange cutting slots and cutting wells in the stope;

[0010] S4. Mining: Opening a large-diameter deep hole at the bottom of the open pit and opening an upward fan-shaped medium-depth hole at the top of the rock drilling tunnel;

[0011] S5. Arrange filling pipes at the bottom of the open pit;

[0012] S6. Filling: Filling shall be carried out in a timely manner after the two-step stoping method is completed.

[0013] Preferably, in the two-step stoping method in step S1, a plurality of stopes are opened in the open-pit bottom, and ore-drawing access roads are connected to the stopes.

[0014] Preferably, the stope includes a first-step stope and a second-step stope, and the first-step stope and the second-step stope are arranged adjacent to each other.

[0015] Preferably, all the first-step stopes are mined first, and then all the second-step stopes are mined.

[0016] Preferably, one side of the ore-drawing access road close to the stope is connected to the drilling drift, and a development drift is opened on the side of the ore-drawing access road far from the drilling drift.

[0017] Preferably, the stope span of the second-step stope is determined according to the orebody dip angle and the spatial layout relationship of the drilling drift.

[0018] Preferably, the first-step stope is filled with cemented tailings, and a closed retaining wall is constructed in the ore-drawing access road connected to the first-step stope and the roadway connected to the goaf.

[0019] Preferably, the second-step stope is first filled with waste rock to 2 / 3 of the goaf. When waste rock filling is no longer possible, classified tailings filling is carried out. After the first-step stope and the second-step stope are filled, a low-permeability cemented filling surface layer is constructed at the open-pit bottom to control the amount of rainwater and accumulated water in the open-pit bottom from seeping into the underground mine.

[0020] Preferably, in step S4, the upward fan-shaped medium-deep holes are first opened at the top of the drilling drift, and then the downward large-diameter deep holes are opened at the open-pit bottom corresponding to the upward fan-shaped medium-deep holes.

[0021] The present invention discloses the following technical effects:

[0022] The present invention mines the orebody through a two-step stoping method combined with the coordinated open-pit and underground mining method. Downward large-diameter deep holes are constructed at the open-pit bottom, and medium-deep hole blasting is carried out at the bottom of the pit to draw ore. The advantages of open-pit mining and underground mining are effectively combined, effectively improving the orebody stoping efficiency.

[0023] The present invention can be effectively applied to the mining of gently inclined ore bodies of boundary isolation pillars at the open-pit bottom, and can effectively increase the recovery of mine resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0025] Figure 1 It is a schematic cross-sectional structure diagram of the present invention;

[0026] Figure 2 For the present invention Figure 1 It is a schematic cross-sectional structure diagram of the cutting shaft at the A-A position in the present invention;

[0027] Figure 3 It is a schematic diagram of the positions of blast holes for combined open-pit and underground mining in the present invention;

[0028] Among them, 1 is the drifter heading; 2 is the ore-drawing drift; 3 is the development drift; 4 is the cutting shaft; 5 is the blast hole; 6 is the cutting slot; 7 is the open-pit bottom; 8 is the cemented filling surface layer; 9 is the first-step stope; 10 is the second-step stope. Specific embodiments

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0030] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

[0031] Embodiment 1

[0032] Referring to Figures 1-3 , the present invention provides a method for combined open-pit and underground mining of the bottom boundary isolation pillar in a metal open-pit mine, including the following steps:

[0033] S1. Stope division: Layout the stopes at the open-pit bottom 7 in a two-step mining method.

[0034] In a further optimized solution, the two-step mining method in step S1 includes multiple stopes opened in the open-pit bottom 7, and the stopes are connected to the ore-drawing drifts 2.

[0035] In a further optimized solution, the stopes include the first-step stope 9 and the second-step stope 10, and the first-step stope 9 and the second-step stope 10 are arranged adjacent to each other.

[0036] For the further optimized plan, all the first-step stopes 9 are mined first, and then all the second-step stopes 10 are mined.

[0037] For the further optimized plan, the second-step stope 10 is first filled with waste rock to 2 / 3 of the goaf. When waste rock filling is no longer possible, classified tailings filling is carried out. After the first-step stope 9 and the second-step stope 10 are filled, a low-permeability cemented filling surface layer 8 is constructed at the bottom of the open-pit 7 to control the amount of rainwater and accumulated water in the bottom of the open-pit 7 seeping into the underground through the cemented filling surface layer 8.

[0038] That is, the specific steps of the two-step mining method are as follows:

[0039] 1. The ore body is divided into a number of first-step stopes 9 and second-step stopes 10 along the dip direction in sequence.

[0040] 2. First, mine the first-step stope 9, and after mining, carry out cemented filling; then go to mine another first-step stope 9.

[0041] 3. After all the first-step stopes 9 are mined and filled, then mine the second-step stope 10, and fill one stope after mining one stope.

[0042] S2. Development engineering layout: A number of drilling headings 1 are arranged along the strike of the ore body at the footwall of the ore body.

[0043] For the further optimized plan, one side of the ore-drawing drift 2 close to the stope is connected to the drilling heading 1, and a development roadway 3 is opened on the side of the ore-drawing drift 2 far from the drilling heading 1.

[0044] For the further optimized plan, the stope span of the second-step stope 10 is determined according to the dip angle of the ore body and the spatial layout relationship of the drilling heading 1.

[0045] For the further optimized plan, the first-step stope 9 is filled with tailings cement, and closed retaining walls are constructed in the ore-drawing drift 2 connected to the first-step stope 9 and the roadway connected to the goaf.

[0046] Blast holes 5 are opened at the top of the drilling heading 1 in the direction towards the first-step stope 9 and the second-step stope 10.

[0047] S3. Cut-through engineering layout: Cut-through grooves 6 and cut-through wells 4 are arranged in the stope.

[0048] S4. Mining: Downward large-diameter deep holes are opened at the bottom of the open-pit 7 and upward fan-shaped medium-depth holes are opened at the top of the drilling heading 1.

[0049] In step S4, first, upward fan-shaped medium-depth holes are opened at the top of the drilling heading 1, and then downward large-diameter deep holes are opened at the bottom of the open-pit 7 corresponding to the upward fan-shaped medium-depth holes.

[0050] First, carry out medium-deep hole cutting at the bottom, and then carry out downhole large-diameter deep hole shaft expansion and cutting; after the ore supply in the cutting slot is completed, carry out stoping by using downhole large-diameter deep hole side blasting and upward fan-shaped medium-deep hole side blasting.

[0051] S5. Arrange filling pipelines at No. 7 in the open-pit bottom.

[0052] S6. Filling: Carry out filling in a timely manner after the two-step stoping method is completed.

[0053] The present invention mines the ore body through a two-step stoping method combined with the open-pit and underground combined mining method. Downhole large-diameter deep holes are constructed at No. 7 in the open-pit bottom, and medium-deep hole blasting at the bottom of the pit is used to draw the bottom and extract ore, effectively combining the advantages of open-pit mining and underground mining, and effectively improving the efficiency of ore body stoping.

[0054] The present invention can be effectively applied to the mining of gently inclined ore bodies in the boundary isolation pillars at the bottom of the open-pit, and can effectively increase the recovery of mine resources.

[0055] Embodiment 2

[0056] Based on Embodiment 1, this embodiment supplements and describes each parameter:

[0057] Stope division: The stope is arranged according to the two-step stoping method. First, stoping the first-step stope No. 9 and constructing the cemented filling surface layer No. 8, and then stoping the adjacent second-step stope No. 10. The stope span of the first-step stope No. 9 is 8-12m, and the stope span of the second-step stope No. 10 is determined according to the ore body dip angle and the spatial layout relationship of the bottom rock drilling roadway.

[0058] Development engineering layout: Drill a rock-drilling drift No. 1 along the ore body strike at an appropriate position on the footwall of the ore body. A cross-cut development drift No. 3 is arranged parallel to the rock-drilling drift No. 1 at a distance of about 10-14m. An ore-drawing drift No. 2 is arranged at a certain angle between the rock-drilling drift No. 1 and the development drift No. 3. The spacing of the ore-drawing drifts No. 2 is about 6m.

[0059] For ore bodies with a small dip angle, according to the stoping sequence, the first-step stope No. 9 and the second-step stope No. 10 share a development drift No. 3; each section is connected by a ramp. Ventilation shafts are arranged on both wings of the ore body to form a ventilation system; stope ore passes are arranged at certain intervals in the sectional roadway to the cross-cut roadway.

[0060] Cutting engineering layout: Arrange a cutting slot No. 6 and a cutting shaft No. 4 in the stope. The width of the cutting slot No. 6 is 4.0m, and the specification of the cutting shaft No. 4 is φ2.0m. The slotting holes are arranged in the cutting drift along the trend of the cutting slot No. 6, with a row spacing of 1m. Vertical deep holes for shaft expansion are arranged around the cutting shaft No. 4, and slotting is carried out by blasting with the cutting raise as the blasting compensation space.

[0061] Stoping: Downward large-diameter deep holes are drilled at the bottom of the open pit 7 with a hole diameter of 165 mm, a row spacing of 2.0 - 2.5 m, a hole spacing of 3.0 - 4.0 m, and a peripheral hole spacing of 1.0 - 1.5 m; upward fan-shaped medium-deep holes are drilled at the top of the drifting roadway 1 with a hole diameter of 76 mm, a row spacing of 1.5 - 1.8 m, and a hole bottom spacing of 1.8 - 2.2 m. The specific construction steps are as follows: First, the medium-deep hole cut is carried out at the bottom, and then the downward large-diameter deep hole is used for shaft expansion and cut. After the ore supply of the cut groove 6 is completed, downward large-diameter deep hole side blasting and upward fan-shaped medium-deep hole side blasting are used for stoping.

[0062] Backfilling: Backfilling pipelines are arranged at the bottom of the open pit 7, and backfilling is carried out in a timely manner after the stoping of the stope is completed.

[0063] For the stope of the first-step stope 9, tailings cemented backfilling is adopted, and closed retaining walls are constructed in the bottom ore-drawing drifts and the roadways connected to the goaf.

[0064] For the second-step stope 10, waste rock is first backfilled to 2 / 3 of the goaf, and graded tailings are backfilled when waste rock backfilling is no longer possible. The waste rock and tailings backfilling can be flexibly adjusted according to production organization.

[0065] The 28-day compressive strength of the backfill body in the first-step stope 9 is not less than 1.0 Mpa, and the 7-day compressive strength of the surface backfill body is 1.2 - 1.5 Mpa; the 7-day compressive strength of the surface backfill body in the second-step stope 10 is 1.2 - 1.5 Mpa.

[0066] Example 3

[0067] Based on Example 1 and Example 2, the specific implementation steps for the boundary ore pillar of the multi-layer gently inclined medium-thick - thick copper ore body at the bottom of the open pit of a certain metal mine are as follows:

[0068] Stope division: The ore body is divided into multiple first-step stopes 9 and second-step stopes 10 from top to bottom. The span of the first-step stope 9 is 12 m, and the span of the second-step stope 10 is 18 m.

[0069] Development engineering layout: Drifting roadway 1 is arranged along the ore body strike at an appropriate position on the footwall of the ore body. A drift development roadway 3 parallel to the ore body is arranged about 10 m away from the drifting roadway 1. Ore-drawing drifts 2 are arranged at a certain angle between the drifting roadway 1 and the drift development roadway 3, and the spacing of the ore-drawing drifts 2 is about 6 m.

[0070] According to the stoping sequence, the first-step stope 9 and the second-step stope 10 share the drift development roadway. Each section is connected by a ramp, and ventilation shafts are arranged on both wings of the ore body to form a ventilation system; stope ore passes are arranged at certain intervals in the sectional roadways to the crosscut roadways.

[0071] Cutting Engineering Layout: One cutting slot 6 and one cutting shaft 4 are arranged in the ore room. The width of the cutting slot 6 is 4.0 m, and the specification of the cutting shaft 4 is φ2.0 m. The slotting holes are arranged in rows along the cutting roadway in the direction of the cutting slot 6, with a row spacing of 1 m. Vertical medium-deep holes for expanding the shaft are arranged around the cutting shaft 4, and blasting slotting is carried out with the cutting raise as the blasting compensation space.

[0072] Ore Caving and Ore Drawing: Downward large-diameter deep holes are constructed at the bottom of the open-pit 7, with a row spacing of 2.0 - 2.5 m, a hole spacing of 3.0 - 4.0 m, and a peripheral hole spacing of 1.0 - 1.5 m. Upward fan-shaped medium-deep holes are constructed at the top of the drifting roadway 1 by a jumbo, with a row spacing of 1.5 - 1.8 m and a hole bottom spacing of 1.8 - 2.2 m. Granular ammonium nitrate explosives are used, and multi-row millisecond non-electric blasting is carried out, with 5 - 10 rows blasted each time. First, the bottom medium-deep holes are used for slotting, with a medium-deep hole diameter of 76 mm, and then the downward large-diameter deep holes are used for shaft expansion and slotting. After the ore supply of the cutting slot 6 is completed, downward large-diameter deep hole side blasting and upward fan-shaped medium-deep hole side blasting are used for stoping. A 3 m 3 load-haul-dump (LHD) is used for ore drawing, and a 3 m 3 remote-controlled diesel LHD is used to assist in recovering the residual ore at the bottom of the trench. The ore drawing in the second-step stope 10 should do a good job in separating ore from waste rock, and the ore is unloaded into the nearby stope ore pass.

[0073] Filling: Filling pipelines are arranged at the bottom of the open-pit 7. After the stoping of the first-step stope 9 and the second-step stope 10, filling should be carried out in a timely manner.

[0074] The first-step stope 9 adopts low-strength tailings cemented filling (cement-sand ratio 1:6 - 1:12), and closed retaining walls are constructed in the bottom ore-drawing drift 2 and the roadway connected to the goaf.

[0075] The second-step stope 10 first conducts waste rock filling to 2 / 3 of the goaf, and when waste rock filling is no longer possible, classified tailings filling is carried out. The waste rock and tailings filling can be flexibly adjusted according to production organization.

[0076] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0077] The embodiments described above are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. An open-pit and underground combined mining method for the bottom boundary barrier pillar in a metal open-pit mine, characterized in that: It includes the following steps: S1. Stope division: Layout the stope at the bottom of the open-pit (7) according to the two-step mining method; S2. Development engineering layout: Arrange several drilling headings (1) along the strike of the ore body at the footwall of the ore body; S3. Cut-off engineering layout: Layout cut-off grooves (6) and cut-off wells (4) in the stope; S4. Mining: Open downward large-diameter deep holes at the bottom of the open-pit (7) and open upward fan-shaped medium-deep holes at the top of the said drilling heading (1); S5. Arrange filling pipelines at the bottom of the open-pit (7); S6. Filling: Conduct filling in a timely manner after the two-step mining method is completed.

2. The open-pit and underground combined mining method for the bottom boundary isolation pillar of a metal open-pit mine according to claim 1, characterized in that: In the two-step mining method in the said step S1, it includes multiple stopes opened in the bottom of the open-pit (7), and the said stopes are connected with ore-drawing headings (2).

3. The open-pit and underground combined mining method for the bottom boundary isolation pillar in a metal open-pit mine according to claim 2, characterized in that: The said stope includes a first-step stope (9) and a second-step stope (10), and the first-step stope (9) and the second-step stope (10) are arranged adjacent to each other.

4. The open-pit and underground combined mining method for the bottom boundary isolation ore pillar in a metal open-pit mine according to claim 3, characterized in that: First, mine all the first-step stopes (9), and then mine all the second-step stopes (10).

5. The open-pit and underground combined mining method for the bottom boundary barrier pillar in a metal open-pit mine according to claim 3, characterized in that: One side of the ore-drawing heading (2) close to the stope is connected with the drilling heading (1), and a development roadway (3) is opened on the side of the ore-drawing heading (2) far from the drilling heading (1).

6. The open-pit and underground combined mining method for the bottom boundary isolation pillar of a metal open-pit mine according to claim 3, characterized in that: The stope span of the second-step stope (10) is determined according to the dip angle of the ore body and the spatial layout relationship of the drilling heading (1).

7. The open-pit and underground combined mining method for the bottom boundary isolation pillar in a metal open-pit mine according to claim 3, characterized in that: The first-step stope (9) adopts tailings cemented filling, and a closed retaining wall is constructed in the ore-drawing heading (2) connected with the first-step stope (9) and the roadway connected with the goaf.

8. The open-pit and underground combined mining method for the bottom boundary isolation pillar in a metal open-pit mine according to claim 3, characterized in that: The second-step stope (10) first conducts waste rock filling to 2 / 3 of the goaf. When waste rock filling cannot be carried out, graded tailings filling is conducted. After the first-step stope (9) and the second-step stope (10) are filled, a low-permeability cemented filling surface layer (8) is constructed at the bottom of the open-pit (7) to control the amount of rainwater and accumulated water in the bottom of the open-pit (7) infiltrating into the underground mine.

9. The open-pit and underground combined mining method for the bottom boundary isolation pillar of a metal open-pit mine according to claim 3, characterized in that: In the said step S4, first open the upward fan-shaped medium-deep holes at the top of the drilling heading (1), and then open the downward large-diameter deep holes at the bottom of the open-pit (7) corresponding to the upward fan-shaped medium-deep holes.

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