Open stope subsequent filling stope structure capable of improving stability of artificial pillars and mining method

Abstract

The invention discloses an open stope subsequent filling stope structure for improving the stability of an artificial ore pillar and a mining method. A first-step stope and a second-step stope are sequentially arranged along an ore body trend or a vertical trend; the first-step stope is of a trapezoidal section structure, and the second-step stope is of an inverted trapezoidal section structure. By the adoption of the structure and the method, collapse or collapse is not prone to occurring in the two-step stope mining, ore removal and later filling processes; the problems that when a traditional open stope subsequent filling method stope structure is used for stoping in a two-step stope, after the vertical side wall of an artificial ore pillar is exposed, the artificial ore pillar is prone to collapse especially under the blasting influence, and normal ore mining and ore removal cannot be achieved in the two-step stope are solved. According to the method, the self-stabilization capacity of the artificial ore pillar in the two-step stope during ore mining and ore removal can be improved, the stability of the artificial ore pillar can be effectively improved, the problem that ores in the two-step stope are difficult to recover due to collapse of the filling body is solved, and the ore dilution rate caused by mixing of the ores due to collapse of the filling body is reduced.

Description

Technical Field

[0001] The invention relates to a mining method, in particular to an open-field subsequent filling stope structure and a mining method for improving the stability of artificial ore pillars. Background Art

[0002] The open-stop and subsequent filling mining method is currently a commonly used method for controlling surface subsidence in underground mining of metal deposits. It is also a mining method with high production efficiency and is widely used when the deposit is large in scale.

[0003] When mining with the traditional open-stop and subsequent filling method, Figure 1 As shown, the stope is divided into chambers and pillars. Generally, the chamber width ranges from 12 to 20 meters, and the pillar width ranges from 8 to 12 meters. Mining begins with the pillars, known as the first-step stope. After ore is extracted from the first-step stope, the goaf is filled with cemented backfill, forming an artificial pillar. Once the backfill reaches a certain strength, the chambers are extracted, known as the second-step stope. After ore is extracted from the second-step stope, the goaf is filled.

[0004] The above-mentioned method for underground resource mining has the following problems: the cross-sections perpendicular to the length direction of both the first-step and second-step mines adopt a rectangular cross-section layout with equal width at the top and bottom. After the first-step mine is mined, the goaf is filled with cemented filling to form artificial pillars. However, due to the low strength of the artificial pillars, the exposed area of ​​the artificial pillars is large during the second-step mine, and the impact of the blasting during the second-step mine often causes the filling body to collapse or collapse, making it impossible for the second-step mine to achieve normal mining and mining, resulting in a large waste of mineral resources. At the same time, it also poses a safety hazard to the normal mining and mining production of the second-step mine. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an open-field subsequent filling mining structure with good safety and improved stability of artificial pillars; the present invention also provides an open-field subsequent filling mining method for improving the stability of artificial pillars.

[0006] In order to solve the above technical problems, the technical solution adopted by the structure of the present invention is: a first-step stope and a second-step stope are arranged in sequence along the strike or vertical strike of the ore body; the first-step stope is a trapezoidal cross-section structure, and the second-step stope is an inverted trapezoidal cross-section structure.

[0007] Furthermore, the one-step stope has an isosceles trapezoidal cross-sectional structure, and the two-step stope has an inverted isosceles trapezoidal cross-sectional structure.

[0008] Furthermore, in the trapezoidal cross-sectional structure of the one-step stope, the lower base width of the trapezoid is the design width of the one-step stope, and the bottom angle is 75° to 85°; in the inverted trapezoidal cross-sectional structure of the two-step stope, the upper base width of the trapezoid is the design width of the two-step stope, and the bottom angle is 75° to 85°.

[0009] To solve the above technical problems, the method of the present invention adopts the above stope structure, and the technical solution adopted includes the following steps: 1) mining each one-step stope, filling the goaf after each one-step stope has finished mining, forming an artificial ore pillar;

[0010] 2) When the artificial pillars reach the designed strength, each second-step stope is mined, and the goaf is filled after each second-step stope is mined.

[0011] Furthermore, in steps 1) and 2), the goaf is filled by cementing filling.

[0012] The beneficial effects of the above technical solution are: the artificial pillars formed by the structure and method of the present invention have an exposed surface that is inclined toward the outside of the empty area of ​​the second-step stope during the second-step stope recovery, and have a high self-stabilizing ability. They are not prone to collapse or collapse during the second-step stope mining, ore removal, and subsequent filling process. This solves the problem that the vertical side walls of the artificial pillars exposed in the traditional open-field and subsequent filling method stope structure are prone to collapse when the second-step stope is recovered, especially under the influence of blasting, causing the second-step stope to be unable to achieve normal mining and ore removal. The present invention can improve the self-stabilizing ability of artificial pillars during the second-step stope mining and ore removal, can effectively improve and improve the stability of artificial pillars, solve the problem that the ore in the second-step stope is difficult to recover due to the collapse of the filling body, and reduce the ore depletion rate caused by the mixing of ore into the collapsed filling body. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0014] Figure 1 This is a schematic diagram of the structure of a conventional open stope followed by filling;

[0015] Figure 2 This is a schematic diagram of the structure of the stope with subsequent filling in the empty stope according to the present invention;

[0016] Figure 3 This is a schematic diagram of the structure of the empty stope followed by filling in Example 1;

[0017] Figure 4 This is a schematic diagram of the structure of the empty stope and subsequent filling stope in Example 2.

[0018] In the figure: Ⅰ, first-step stope; Ⅱ, second-step stope; ①, cemented backfill; ②, body to be mined; H, design height of stope; B1, bottom width of first-step stope; B2, bottom width of second-step stope; B1′, top width of first-step stope; B2′, top width of second-step stope; α, slope angle of artificial pillar; A-A is the center line of the pillar between the left panel; A′-A′ is the center line of the pillar between the right panel. DETAILED DESCRIPTION

[0019] Figure 2 As shown, the open-stope and subsequent filling stope structure for improving the stability of artificial pillars is designed using a segmented open-stope and subsequent filling mining method and panel mining. Within the panel, the stope is arranged along the strike of the ore body or perpendicular to the strike, and is divided into a one-step stope I and a two-step stope II. It is best to ensure that both sides of the panel pillar are arranged in the one-step stope I arrangement. The above division process can adopt the traditional mining structure design process for dividing one-step and two-step stopes. The cross-section of the one-step stope perpendicular to the length of the ore block is a trapezoidal cross-section structure that is narrow at the top and wide at the bottom, preferably an isosceles trapezoidal cross-section structure; the cross-section of the two-step stope perpendicular to the length of the ore block is an inverted trapezoidal cross-section structure that is wide at the top and narrow at the bottom, preferably an inverted isosceles trapezoidal cross-section structure. In the description of the trapezoid in this article, the two parallel sides are called the bases of the trapezoid: the bottom base is the trapezoid, and the top base is the trapezoid's upper base; the two sides are the trapezoid's waist; and the angle between the waistline and the bottom base is the base angle. An inverted trapezoid is a trapezoid turned upside down, with the lower base at the top and the upper base at the bottom.

[0020] Figure 2 As shown, the present invention improves the stability of artificial pillars with an open-pit and subsequently filled stope structure. In the trapezoidal cross-section structure of the one-step stope (Ⅰ), the lower base width of the trapezoid is the design width of the one-step stope, that is, the bottom width B1 of the one-step stope is the design width of the one-step stope, and preferably the bottom width B1 of the one-step stope is 8-20m; the bottom angle α of the trapezoid is 75°-85°, that is, the angle of the lower part of the one-step mining block section, which is also the slope angle of the artificial pillar, is 75°-85°. In the inverted trapezoidal cross-section structure of the two-step stope (Ⅱ), the upper base width of the trapezoid after being upright is the design width of the two-step stope, that is, the bottom width B2 of the two-step stope is the design width of the two-step stope, and preferably the bottom width B2 of the two-step stope is 12-20m; the bottom angle α of the trapezoid is 75°-85°, that is, the angle of the upper part of the two-step mining block section, which is also the slope angle α of the artificial pillar, is 75°-85°. The height of the stope adopts the design height, and the stope design height H is preferably 15 to 20 meters.

[0021] The top width B1′ of the first-step stope is calculated using the following formula (1), and the top width B2′ of the second-step stope is calculated using the following formula (2):

[0022]

[0023] In the formula, B1 is the bottom width of the one-step stope, that is, the design width of the one-step stope, in m; B1′ is the top width of the one-step stope, in m; H is the design height of the stope, in m; α is the slope angle of the artificial pillar, that is, the bottom angle of the trapezoidal section of the stope, in degrees; B2 is the bottom width of the two-step stope, in m; and B2′ is the top width of the two-step stope, in m.

[0024] Figure 2 As shown, the present method for mining with subsequent filling in a void for improving the stability of artificial pillars adopts the above-mentioned stope structure and includes the following steps: 1) mining each first-stage stope I, i.e., mining the first-stage mining block; after the ore is mined in each first-stage stope I, the void is filled, and the cemented filling body ① of the filled first-stage stope forms an artificial pillar; the first-stage stope I adopts cemented filling;

[0025] 2) When all artificial pillars adjacent to the second-step stope II have reached their designed strength, the ore bodies to be mined ② of each second-step stope II are mined, and the goaf is filled after the ore is mined in each second-step stope II; the second-step stope II is filled with low-proportion tailings cementation;

[0026] 3) Repeat steps 1) and 2) until mining is completed.

[0027] Example 1: The specific implementation of the stope structure and mining method for improving the stability of artificial pillars is as follows.

[0028] Figure 3 As shown in the figure, a certain iron ore body is relatively thick, with a Proctor hardness coefficient of f = 12-14. The design adopts a sub-level open-stop and subsequent backfill mining method, with panel mining. The panel length is 120m, and the width is equal to the ore body thickness. The column width between the panels is 15m, and the sub-level height is 20m. The ore blocks are arranged along the strike of the ore body within the panel. The first and second mining blocks are divided perpendicular to the strike of the ore body, and the ore blocks are both 20m wide. The first mining blocks are backfilled with cement, while the second mining blocks are backfilled with low-proportion tailings. Figure 3 In the diagram, line A-A is the center line of the inter-panel columns on the left, and line A'-A' is the center line of the inter-panel columns on the right. The two lines form a complete panel area.

[0029] 1) Calculate the upper width B1′ of the first-stage stope:

[0030] According to the mining method design, H = 20m, B1 = 20m, and the slope angle α = 80°. From formula (1), the upper width B1′ of the first-stage stope can be obtained as:

[0031]

[0032] 2) Calculate the upper width B2′ of the second-step stope:

[0033] According to the mining method design, H = 20m, B2 = 20m, and the slope angle α = 80°. From formula (2), the upper width B2′ of the second-step stope can be obtained as:

[0034]

[0035] 3) Divide the plate area into blocks:

[0036] In the panel area, perpendicular to the strike direction of the ore body, according to the calculated size, from the center line of the panel column, according to Figure 3 The first-step stope I and the second-step stope II are arranged in sequence. Taking into account the recovery of the panel area pillars, when dividing the ore blocks in the panel area, it is ensured that both sides of the panel area pillars are arranged in the form of the first-step stope I.

[0037] 4) Mining:

[0038] Mining is carried out on the first-step stope I of each stope, that is, the first-step mining blocks are mined; after the first-step stope I of each stope is mined, the goaf is filled, and the cemented filling body ① of the filled first-step stope forms an artificial pillar; the first-step stope I adopts cemented filling; when the artificial pillar of each stope reaches the designed strength, the to-be-mined body ② of the second-step stope II of each stope is mined, and after the second-step stope II of each stope is mined, the goaf is filled; the second-step stope II adopts low-proportion tailings cemented filling; the above mining process is repeated until mining is completed.

[0039] Example 2: The specific implementation of the stope structure and mining method for improving the stability of artificial pillars is as follows.

[0040] Figure 4 As shown, a certain iron ore body is relatively thick, with a Proctor hardness coefficient of f = 10-12. The design utilizes a sub-level open-stop and subsequent backfill mining method, with panel mining. The panel length is 120 meters, and its width is equal to the ore body thickness. The inter-panel pillar width is 16 meters, and the sub-panel height is 15 meters. Within the panel, the ore blocks are arranged along the strike of the ore body, with first- and second-step mining blocks perpendicular to the strike. The first-step mining blocks are 10 meters wide, and the second-step mining blocks are 14 meters wide. The first-step mining blocks are cemented backfilled, while the second-step mining blocks are cemented backfilled with low-proportion tailings. Figure 3 In the diagram, line A-A is the center line of the inter-panel columns on the left, and line A'-A' is the center line of the inter-panel columns on the right. The two lines form a complete panel area.

[0041] 1) Calculate the upper width B1′ of the first-stage stope:

[0042] According to the mining method design, H = 15m, B1 = 10m, and the slope angle α = 82°. From formula (1), the upper width B1′ of the first-stage stope can be obtained as:

[0043]

[0044] 2) Calculate the upper width B2′ of the second-step stope:

[0045] According to the mining method design, H = 15m, B2 = 14m, and the slope angle α = 82°. From formula (2), the upper width B2′ of the second-step stope can be obtained as:

[0046]

[0047] 3) Divide the plate area into blocks:

[0048] In the panel area, perpendicular to the strike direction of the ore body, according to the calculated size, from the center line of the panel column, according to Figure 3 The first-step stope I and the second-step stope II are arranged in sequence. Taking into account the recovery of the panel area pillars, when dividing the ore blocks in the panel area, ensure that both sides of the panel area pillars are arranged in the first-step stope I.

[0049] 4) Mining:

[0050] Mining is carried out on the first-step stope I of each stope, that is, the first-step mining blocks are mined; after the first-step stope I of each stope is mined, the goaf is filled, and the cemented filling body ① of the filled first-step stope forms an artificial pillar; the first-step stope I adopts cemented filling; when the artificial pillar of each stope reaches the designed strength, the to-be-mined body ② of the second-step stope II of each stope is mined, and after the second-step stope II of each stope is mined, the goaf is filled; the second-step stope II adopts low-proportion tailings cemented filling; the above mining process is repeated until mining is completed.

Claims

1. A stope structure with subsequent filling to improve the stability of artificial pillars, characterized by: A first-step stope (I) and a second-step stope (II) are arranged in sequence along the strike or vertical strike of the ore body; the first-step stope (I) is a trapezoidal cross-section structure, and the second-step stope (II) is an inverted trapezoidal cross-section structure.

2. The stope structure for improving the stability of artificial pillars according to claim 1, characterized in that: The first-step stope (I) is an isosceles trapezoidal cross-section structure, and the second-step stope (II) is an inverted isosceles trapezoidal cross-section structure.

3. The stope structure for improving the stability of artificial pillars according to claim 2, characterized in that: In the trapezoidal cross-sectional structure of the one-step stope (I), the lower base width of the trapezoid is the design width of the one-step stope, and the bottom angle is 75° to 85°; in the inverted trapezoidal cross-sectional structure of the two-step stope (II), the upper base width of the trapezoid is the design width of the two-step stope, and the bottom angle is 75° to 85°.

4. A method for mining with subsequent filling to improve the stability of artificial pillars, using the stope structure according to claim 1, 2 or 3, characterized in that: The method comprises the following steps: 1) mining each first-stage stope (I), and filling the mined-out area after the ore is mined in each first-stage stope (I) to form an artificial ore pillar; 2) When the artificial pillars reach the designed strength, each second-step stope (II) is mined, and the goaf is filled after the ore is mined in each second-step stope (II).

5. The open-pit subsequent filling mining method for improving the stability of artificial pillars according to claim 4, characterized in that: In steps 1) and 2), the goaf is filled by cementing filling.

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