Modified tailing particle filling process for converting outdoor metal mine into underground metal mine

Abstract

The invention discloses a modified tailing particle filling process for an open-pit-to-underground metal mine, which comprises the following steps: 1) during open-pit-to-underground mining, pre-filling an open-pit-to-underground goaf formed by mining to form a discrete medium pre-filling body; (2) sublevel mining is carried out on the underground ore body, in the mining process of each section, discrete media are continuously used for pre-filling, and after mining, the discrete media are settled to fill the section of the goaf; and (3) filling the upper part of the discrete medium pre-filling body with the modified tailing particles until all tailings mined outdoors and underground in the pre-filled open-air-underground goaf can be eliminated and fixed, and pressurizing and solidifying to form a solidified filling body. The method has the advantages of continuously absorbing the tailings and improving the mining environment, safe and continuous tailings absorbing can be achieved, safe and efficient mining of an underground production system is guaranteed, deformation and damage of a goaf can be effectively controlled, and large-scale, mechanization and automation of the underground mining system can be conveniently achieved.

Description

Technical Field

[0001] The invention relates to the technical field of mining, in particular to a modified tailings particle filling process for an open-pit-to-underground metal mine. Background Art

[0002] Open-pit-to-underground metal mines generally have thick ore bodies, steep inclinations, and low grades. During the open-pit mining period, a large amount of tailings accumulated, which urgently needs to be expanded. The use of caving mining in the process of underground conversion facilitates mechanized mining, which is safe and efficient. However, caving mining can cause serious surface collapse, continuous sliding of the slopes in the open-pit goaf, and the connection between the underground mining area and the open-pit goaf causes flooding and mudslides. If the backfill mining method is used, there are problems such as complex mining process, low recovery efficiency, high cost, and difficulty in using large-scale machinery and equipment to achieve large-scale mining. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a modified tailings particle filling process for an open-pit-to-underground metal mine.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention includes the following steps: 1) when converting open-pit mining to underground mining, waste rock stripped from the original open-pit mining, ore pre-selection waste, underground production system development waste rock, or other bulk medium solid waste is selected as bulk medium to pre-fill the open-pit-underground goaf formed by mining to form a bulk medium pre-filling body; 2) The underground ore body is mined in sections. During each mining process, the bulk medium is continuously used for pre-filling. After mining, the bulk medium settles and fills the goaf of the section; 3) Until all tailings from open-pit and underground mining can be eliminated in the pre-filled open-pit-underground goaf, modified tailings particles are used to fill and pressurize the upper part of the bulk medium pre-fill body to form a consolidated filling body.

[0005] Furthermore, in step 1), the pre-filling height is greater than 0.2 times the vertical height of the underground mined ore body.

[0006] Furthermore, in step 1), the average particle size of the dispersed medium is 30<dp<150mm.

[0007] Furthermore, in step 3), the modified tailings particles use tailings as the main material, and are added with glue powder and fibers.

[0008] Furthermore, cement is used as the binder powder, the lime-sand ratio is 1:6-1:8, the fiber content reaches 0.5%, the slurry concentration is 75%-78%, and the strength after solidification is greater than 7Mpa.

[0009] The beneficial effects of the above technical scheme are as follows: the present invention mainly uses modified tailings consolidation particles as the main filling body to fill the open-pit-underground void area, dispose of tailings, control the open-pit slope angle and the stability of the underground goaf, effectively protect the stability of the sidewall of the open-pit goaf, reduce the collapse and damage of the surface topography, and reduce the ecological damage and secondary disasters caused by mining; at the same time, by filling the goaf with modified tailings consolidation particles, the bulk medium itself has sufficient fluidity, which can not only fully unload the upper ground pressure of the underground mining field, but also ensure the fluidity of the caving method, effectively isolate the open-pit-underground goaf, and ensure the safe and efficient mining of the underground production system. The present invention is different from the traditional solid medium filling mining method. It uses modified tailings consolidation particles as the main filling body to fill the open-pit-underground goaf. The bulk medium filling body does not remain static, but flows and settles continuously with underground mining, which can effectively control the deformation and collapse of the goaf, and fully ensure the fluidity required by the underground caving mining production system. The present invention has the advantages of continuous disposal of tailings and improvement of mining environment. It can not only realize the safe and continuous disposal of tailings and ensure the safe and efficient mining of underground production systems, but also effectively control the deformation and damage of goaf areas, and facilitate the scale, mechanization and automation of underground mining systems. It is suitable for large-scale open-pit to underground metal mines.

[0010] The present invention uses modified tailings to consolidate particles to fill the open-pit and underground goaf, and adopts the caving mining method underground, which has two advantages: a large amount of tailings can be consumed, the mining environment can be improved, and the ecological damage to the surface landform is small. The deformation of the underground rock formation can be effectively controlled, which is safe and efficient, and is convenient for enterprises to realize large-scale mechanized mining. While absorbing the tailings, the present invention maintains the stability of the surface open-pit slope, reduces surface collapse, and controls the deformation of the deep underground rock formation. At the same time, the caving mining method is adopted underground, which is conducive to large-scale mechanized mining, safe and efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0012] Figure 1 It is a schematic diagram of the structure of the underground mining section before the collapse of the present invention; Figure 2 It is a schematic diagram of the structure after the collapse of this section of underground mining according to the present invention.

[0013] In the figure: 1-the final state of the open pit; 2-consolidated filling body; 3-consolidated body conveyor belt; 4-road; 5-pre-filling body; 6-mining section; 7-fan-shaped blasthole; 8-rock drilling and blasting section of the hanging wall mine; 9-drilling hole. DETAILED DESCRIPTION

[0014] The modified tailings particle filling process of this open-pit-to-underground metal mine adopts the caving mining method for underground mining. The mining process is: open-pit and underground independent development systems or local joint development systems. First, the side ore body is mined by caving. Before mining, prefabricated bulk media should be used to fill the height of a step above the height of the mined area. The segment height is a step height. During mining, the side slope step surface is withdrawn by extrusion blasting. During the mining of the side ore body, the underground ore body begins to form a mining and cutting project. After the mining of the side ore body is completed, the underground mining sequence should be retreated to the side slope. The ore body has a large inclination thickness, and a relatively large segment height can be selected. If the mining and filling level conditions are met, the segment height should be selected as 20m.

[0015] The modified tailings particle filling process of the open-pit-to-underground metal mine prepares modified tailings consolidation particles of a certain particle size and strength, and combines them with the underground mining process on top of a pre-filled bulk cushion layer (waste rock stripped from open-pit mining, ore pre-selection waste, etc.), so as to only keep the filling interface in a certain plane shape, thereby achieving the purpose of continuous tailings removal. The open-pit-to-underground mining environment method: After the composite covering layer requirements of the modified tailings consolidation particles and the bulk medium filling body are formed, the modified tailings filling process and underground caving recovery can be carried out simultaneously, which simplifies the filling process while improving the underground mining environment in terms of safety and efficiency. The detailed steps are as follows: 1) In the process of converting open-pit mining to underground mining, select waste rock stripped from the original open-pit mining, ore pre-selection waste, underground production system development waste rock, or other bulk solid waste as bulk medium; screen the pre-filling bulk particle size, its structure should be close to the particle size structure of the collapsed ore, the maximum block size should be less than 2 times the maximum block size of the collapsed ore, the average particle size is 30<dp<150, and the grading should be good; to ensure that the bulk medium filling body has sufficient fluidity.

[0016] 2) Use loose media to pre-fill the underground voids and open voids formed by mining, and fill the surface as flat as possible. Multiple filling points can be set up to ensure the formation of loose medium filling bodies. The pre-filling position is selected at the ore body on the lower plate side of the first segment of underground mining. According to the rock properties of the lower plate, the collapse angle is selected to determine the entry prohibition line. Outside the safe distance where the rock movement line intersects the open pit, the appropriate nodes and ports of the original open-pit road transportation system are selected to make retaining walls; the surface filling is carried out by automobile transportation and rock removal. Before the completion of mining, the minimum filling height of the loose medium filling body is greater than 0.2 times the vertical height of the underground mining ore body through the circular forward push method, and the residual resident ore body on the side of the open-pit mine is covered. The highest filling height can be filled to the level of the appropriate nodes and ports of the original open-pit road transportation system.

[0017] 3) While pre-filling, prepare modified tailings consolidation particles. In order to meet the freeze-thaw, impact and stability of the particle size structure of the bulk medium itself under high ground stress during the filling process, the modified tailings consolidation particles use tailings as the main material, cement as the binder powder, and fiber is added; the mass ratio of cement to tailings, that is, the ash-sand ratio, is 1:6-1:8 in the modified tailings consolidation particles, and the fiber addition amount is 0.5wt% of the total weight of the modified tailings consolidation particles; polypropylene fiber is preferably used as the fiber; the modified tailings consolidation particles are added with water to form a modified tailings consolidation slurry, and the slurry concentration is 75%-78wt%.

[0018] 4) The underground ore body is mined in sections. During each mining process, the bulk medium is continuously used for pre-filling. After mining, the bulk medium settles and fills the goaf of that section. Estimate the amount of tailings after the open-pit and underground mining is complete. During the underground section mining and pre-filling process, the void area formed on the top of the pre-filling body can eliminate all the tailings. After the mining of that section is completed, the modified tailings consolidation particles are used to fill and pressurize the top of the pre-filling body to form a consolidated filling body; until the open-pit to underground mining is completed.

[0019] The filling process of the consolidated filling body is as follows: modified tailings consolidation particles are mixed with water, filled on the upper part of the bulk medium filling body, and then pressurized to achieve consolidation, and the surface is filled as flat as possible to form a consolidated filling body; when pressurizing, the mechanical parameters of the extrusion granulator are adjusted to control the pressure range of 1 to 3 MPa to ensure the quality and consistency of the particles; the compressive strength of the consolidated filling body is greater than 7 MPa, preferably close to the strength of the ore. Example

[0020] 1) Open-pit mining process: Figure 1 As shown, during the open-pit mining process, the hanging wall ore is drilled in sections 8 and mined by caving method. The hanging wall ore in each section is drilled 9 and filled with explosives, and then blasted in sections. As the residual resident ore body in the open-pit side wall is mined and released, the waste rock continues to be filled. That is, due to the large inclination of the ore body, during the side wall mining process (caving mining), the waste rock is filled into the empty area as the empty area is formed. At this time, it is necessary to ensure that the height of the waste rock is higher than the upper limit height of the mining of the side wall ore body on the upper plate. After the mining of the surrounding ore bodies is completed, the deep underground ore body is recovered by plane ore discharge. Formation such as Figure 1 , Figure 2 The open-air final realm 1 is shown.

[0021] 2) Underground mining and pre-filling process: The underground ore body is mined in sections, and each section is as follows: Figure 1 , Figure 2The mining sections 6 shown in the figure are caving with fan-shaped blastholes 7 in each mining section, and waste rocks are transported by roads 4 and consolidation body conveyor belts 3. Before the first underground mining section is carried out, the open-pit empty area is pre-filled with loose medium, and the height of the loose medium pre-filled at the bottom of the open pit is at least 0.2 times the height of the first section, thereby maintaining the stability of the slope angle, controlling the circulating ground pressure, creating the conditions for ore release, preventing impact ground pressure, preventing water seepage, preventing air leakage, preventing mudslides and cold, and other multi-functional loose medium pre-filling bodies 5. During the first section mining process, as the mining progresses and the goaf deforms and collapses, the loose medium pre-fill flows and settles accordingly, thereby filling the goaf of the first section.

[0022] Before the second stage mining, the empty area of ​​the first stage is pre-filled with a loose medium. The upper surface of the pre-filled body after the first stage is taken as the level, and the loose medium is pre-filled upward to a height of at least 0.2 times the height of the second stage. During the second stage mining process, as the mining progresses, as the goaf deforms and collapses, the loose medium pre-fill flows and settles, thereby filling the goaf of the second stage.

[0023] 6) Underground mining and consolidation filling process: The third and subsequent sections use modified tailings consolidation particles to consolidate and fill above the pre-filling body 5 to form a consolidation filling body 2; the tailings can be continuously transported to the open pit through the prepared modified tailings consolidation particles until the mining of the open pit to underground mining is completed, the open pit is filled, and then the surface greening and reclamation is carried out in the later stage. When mining to the third section, the movement angle β, that is, the rock movement angle of the upper and lower sides of the mined section, should be selected in combination with the rock mass lithology and joints, and the filling control should be selected to control the possible collapse height and safe road intersection underground, and the modified tailings consolidation particles should be transported by belt transportation. At about 30° in front of the belt layout position, two steeper slopes are selected, and modified tailings particles are collaboratively filled by means of automobile rock removal outside the underground mining movement range. The focus is on maintaining the stability of the spatial position relationship between the horizontal plane of the bulk medium filling body and the open-pit goaf (open-pit mine), preventing the formation of concentrated mudslide water sources, and creating safe mining conditions.

Claims

1. A modified tailings particle filling process for an open-pit to underground metal mine, characterized in that: The method comprises the following steps: 1) when converting open-pit mining to underground mining, waste rock stripped from the original open-pit mining, ore pre-selection waste, underground production system development waste rock, or other bulk solid waste is selected as bulk medium to pre-fill the open-pit-underground goaf formed by mining to form a bulk medium pre-filling body; 2) The underground ore body is mined in sections. During each mining process, the bulk medium is continuously used for pre-filling. After mining, the bulk medium settles and fills the goaf of the section; 3) Until all tailings from open-pit and underground mining can be eliminated in the pre-filled open-pit-underground goaf, modified tailings particles are used to fill and pressurize the upper part of the bulk medium pre-fill body to form a consolidated filling body.

2. The modified tailings particle filling process for an open-pit to underground metal mine according to claim 1 is characterized by: In the step 1), the pre-filling height is greater than 0.2 times the vertical height of the underground mining ore body.

3. The modified tailings particle filling process for an open-pit to underground metal mine according to claim 1 is characterized by: In the step 1), the average particle size of the dispersed medium is 30<dp<150mm.

4. The modified tailings particle filling process for an open-pit to underground metal mine according to claim 1, 2 or 3, characterized in that: In the step 3), the modified tailings particles are made of tailings as the main material, and are added with glue powder and fibers.

5. The modified tailings particle filling process for an open-pit to underground metal mine according to claim 4 is characterized by: Cement is used as the binder powder, the lime-sand ratio is 1:6-1:8, the fiber content reaches 0.5%, the slurry concentration is 75%-78%, and the strength after solidification is greater than 7Mpa.

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