Method for stoping residual ore in last section of stope by non-pillar sublevel caving method for soft broken thick and large ore body

Abstract

The invention discloses a soft broken thick and large ore body sill-pillar-free sublevel caving method stope last sublevel residual ore stoping method which comprises the following steps: delimiting a stoping area and a mining preparation area in the last sublevel, and determining operation tasks of each area; a'main access' and a'secondary access' are arranged in the stoping area, and meanwhile, retreating is carried out to realize full stoping of residual ore in the area so as to ensure the productivity of a stope; in the back mining process of the back mining area, the excavation and support of the secondary drift and the rock drilling work of ore breaking blast holes of the primary drift and the secondary drift are completed in the back mining area, so that the mining operation of the back mining area is replaced; and after the back mining of the back mining area is finished, the to-be-mined area is converted into the back mining area, meanwhile, the to-be-mined area is re-delimited at the left and right adjacent parts of the new back mining area, and the two areas circularly and alternately operate until the back mining of the whole section is finished, so that full back mining of the residual ore of the last section is realized. By means of the method, safe, efficient and sufficient stoping of the residual ore in the last section of the stope through the sill-pillar-free sublevel caving method can be achieved under the soft-broken thick and large ore body condition.

Description

Technical Field

[0001] The invention belongs to the technical field of ore mining methods, and in particular relates to a method for recovering residual ore in the last segment of a soft-broken thick and large ore body without a bottom pillar, a sublevel caving method. Background Art

[0002] The pillarless sublevel caving method has the advantages of high mechanization, high operating efficiency, low mining cost and production safety, and occupies a high application ratio in my country's underground metal mines. Due to the special diamond-shaped stope structure of the pillarless sublevel caving method, the peach-shaped pillars and ridge residues formed after the mining of this segment route cannot be recovered in this segment, but can only be recovered in the next segment. Therefore, when the pillarless sublevel caving method is mined to the last segment, since there is no mining project below the last segment, the peach-shaped pillars and ridge residual ore cannot be mined and remain in the last segment. According to statistics, the peach-shaped pillars and ridge residual ore usually account for 20%~30% of the segment ore volume. If other measures are not taken to recover them, this part of the ore volume will become a permanent loss.

[0003] At present, the most commonly used method for mining residual ore in the last segment of the pillarless sublevel caving mining site is to arrange an additional route from the lower wall connecting tunnel to the central position of the peach-shaped pillar between the two adjacent routes to recover the residual ore after the overall recovery of the last segment route. In this scheme, the encrypted route is usually at the same elevation as the original recovery route. When the quality of the mine ore and rock is good and the ore body is of medium thickness, the length of the encrypted route is not long and it is easy to maintain stability. At this time, this method has good feasibility for the recovery of residual ore. However, when the mine ore and rock are broken and the ore body is thick, the traditional method is no longer applicable, which is specifically reflected in the following points: 1. During the mining process of the original approach, frequent fan-shaped medium-deep hole blasting operations made the originally relatively broken peach-shaped pillars even more broken. At this time, it was extremely difficult to construct the residual ore mining approach in the peach-shaped pillars. Even if the excavation and support operations were completed, its stability was difficult to guarantee and the operation safety was very poor; 2. For thick and large broken ore bodies, after the original approach is completely mined, the residual ore recovery approach is constructed in the peach-shaped ore pillar, which will result in a very long residual ore recovery approach, which will prolong the construction period and recovery period, increase the safety risk of the operation, and at the same time, under the condition of broken ore and rock, the longer the approach is, the more difficult it is to maintain its stability; 3. When the residual ore recovery route is arranged at the same elevation as the original route, the thickness of the pillar between the two will become very small (usually only 2~4m), which will lead to extremely poor stability of the residual ore recovery route and the safety of the operation cannot be guaranteed. In addition, arranging the residual ore recovery route at the same elevation as the original route is not conducive to fully recovering the peach-shaped ore pillars.

[0004] It can be seen from this that for the pillarless staged caving method of soft, thick and large ore bodies, in order to achieve safe and efficient recovery of the residual ore in the last stage, it is necessary to develop a more suitable residual ore mining method based on the characteristics of the ore and rock conditions and the scale of the ore body. Summary of the invention

[0005] In order to solve the problems of difficulty, low efficiency and poor safety in recovering the residual ore in the last segment of the pillarless sublevel caving mining site under the conditions of soft, broken, thick and large ore bodies, a mining plan for the last segment residual ore is designed, with the purpose of improving the ore recovery rate of the last segment of the pillarless sublevel caving mining site under the conditions of soft, broken, thick and large ore bodies, and improving the technical and economic benefits of mining.

[0006] To this end, the present invention adopts the following technical solutions: In order to realize the safe and efficient mining of residual ore in the last section of the soft, thick and large ore body without pillars in the sublevel caving method, after the main access road of the last section is constructed in place, the mining area and the preparation area are demarcated from the initial mining position of the mining field. These two areas are usually adjacent to each other and rectangular in shape. The scale is basically the same, but the operation tasks of each area are different. The mining area is mainly to realize the timely and full recovery of residual ore and ensure the production capacity of the mining field. The preparation area is mainly to complete the mining and preparation of residual ore mining, so as to take over the mining area. There are two types of mining access roads in the mining area, namely "main access road" and "secondary access road". The so-called "main access road" is the mining access road arranged in the last section according to the conventional design, which is used to realize the conventional mining of the ore in the last section; the so-called "secondary access road" is a mining access road added between two adjacent "main access roads". Its main task is to realize the full recovery of peach-shaped pillars and ridge residual ore between the two adjacent "main access roads".

[0007] When the mining area is in operation, the "main approach" and "secondary approach" are withdrawn at the same time, but the adjacent "main approach" on the left and right needs to be 1~2 ore-breaking steps ahead of the "secondary approach" to facilitate the formation of peach-shaped ore pillars and ridge residues. The "secondary approach" uses upward fan-shaped blastholes for ore dropping, just like the "main approach", and the ore-breaking step of the "secondary approach" is consistent with the ore-breaking step of the "main approach", so that the two blast rows are on the same vertical plane. When mining, the "main approach" mines in a low-depletion manner, that is, when the waste rock arrives at the mine outlet normally during the mining process, the mining stops, while the "secondary approach" mines in a cut-off grade manner. The advantage of this is that more ridge residual ore can be retained in place, and finally released as pure ore in the "secondary approach", thereby improving the quality of ore recovery. By alternating mining of the "main and secondary approaches" in the mining area, the residual ore in the area can be fully recovered.

[0008] During the operation in the mining area, the preparation mining area needs to actively complete the construction of the "secondary approach" in the area. The construction design method of the "secondary approach" in the preparation mining area is to construct a horizontal connecting road at the end of the preparation mining area (based on the retreat direction) to connect the main approaches in the area. The bottom plate of the connecting road is at the same level as the bottom plate of the main approach. In the connecting road, an opening is selected at the central position of the column between two adjacent main approaches to construct the "secondary approach". During construction, the maximum climbing angle of the residual ore mining equipment is used to sink down the slope until the "secondary approach" is reached. The top plate of the "secondary access road" is flush with the bottom plate of the "main access road" and then pushed forward in parallel, so that the "secondary access road" and the "main access road" are staggered in the horizontal direction, avoiding the mutual influence of the stability when the two are at the same elevation. The sinking sections of the connecting road and the "secondary access road" are supported by a single layer of shotcrete mesh + steel arch frame, and the parallel section of the "secondary access road" is supported by a single layer of anchor shotcrete mesh. The cross-sectional specifications of the connecting road and the "secondary access road" are based on meeting the minimum operating size requirements of the residual ore recovery equipment. The smaller the better for its stability, it is generally recommended to be high ( h )×Width( b )=2.5~3.5m×2.5~3.5m.

[0009] During the operation in the mining area, in addition to completing the excavation work of the "secondary approach", the preparation mining area must also do a good job of rock drilling in the blastholes of the "secondary approach" and "main approach" so as to take over the operations in the mining area in time. After the mining in the mining area is completed, the preparation mining area will be immediately converted into the mining area, and the preparation mining area will be re-demarcated. In this way, the two areas will operate alternately until the entire segment mining is completed, and the residual ore in the last segment can be fully recovered.

[0010] The mining area and the preparation area are usually rectangular in shape, and the length along the approach direction is L From the sinking section of the "secondary access road" l 1 and parallel segments l 2. Two parts, sinking section l The length of 1 depends on the maximum climbing angle of the residual ore recovery equipment α , parallel segment l The length of 2 depends on the rock Proctor coefficient f The value is usually 20~60m. The smaller the Proctor coefficient, the shorter the value. The width in the direction perpendicular to the approach W The number of “main access roads” included in the mining area N and access distance S The product of N The value is usually 3 to 6, the worse the lithology is, the higher the N The smaller the value of .

[0011] The beneficial effects of the present invention are: 1. Under the condition of soft, broken, thick and large ore bodies, the "secondary approach" used to recover the residual ore is constructed and mined in sections, which not only realizes the timely mining of residual ore and improves the mining efficiency of residual ore, but also helps to improve the stability of the residual ore recovery project; 2. The "secondary access road" used for recovering residual ore is sunk below the floor elevation of the "main access road", so that the two are intertwined in the horizontal direction, which is conducive to maintaining the stability of the "main access road" and the "secondary access road" and ensuring the safety of residual ore mining operations; 3. The construction of the "secondary approach" is completed before the collapse of the "main approach", which avoids the problem of further crushing of peach-shaped ore pillars due to the collapse of the main approach and the inability to construct the "secondary approach", which is conducive to the excavation and support of the "secondary approach"; 4. The “main approach” and “secondary approach” are withdrawn at the same time, and the low-diluted ore-drawing method and the cut-off grade ore-drawing method are adopted respectively, which is conducive to fully recovering the ore and improving the ore recovery quality; 5. The mining area is divided into a recovery area and a preparation area. The work tasks of the two operating areas are clear and do not interfere with each other. Through the cyclic alternating operations of the two operating areas, the mining area's production capacity can be ensured, and the timely and full recovery of residual ore can be achieved, thereby improving the overall economic benefits of the final segment mining. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of the residual ore morphology in the last segment; Figure 2 It is a plan view of the mining method of the present invention; Figure 3 yes Figure 2 The A-A' section in the middle shows the state when both the main approach and the secondary approach are not mined; Figure 4 yes Figure 2 The A-A' section in the middle shows the state after the main approach has surpassed the previous secondary approach; Figure 5 yes Figure 2 Section B-B' of the middle mining method; Figure 6 It is a schematic diagram of the division of mining areas in a mining field of the mining method of the present invention; In the figure: 1—main approach; 2—connecting road; 3—secondary approach; 4—collapsed surrounding rock; 5—uncollapsed ore body; 6—bottom plate surrounding rock; 7—secondary approach mining blasthole; 8—main approach mining blasthole; 9—collapsed ore. DETAILED DESCRIPTION

[0013] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments: (1) After the main approach 1 of the last segment is arranged in place, a mining area and a preparation area are first demarcated at the initial mining position of the stope according to the mining direction of the approach. Both areas are rectangular in plan and adjacent to each other on the left and right. This can avoid interference between the two areas. Figure 2 shown.

[0014] (2) Construct "Secondary Access Road 3" in the first mining area designated in the stope. During construction, first construct a horizontal connecting road 2 at the end of the area (based on the direction of withdrawal) to connect the "Main Access Roads 1" in the area. The bottom plate of the connecting road 2 is at the same elevation as the bottom plate of the "Main Access Road 1". In the connecting road 2, choose to open the "Secondary Access Road 3" in the middle of the intermediate pillars of the two adjacent "Main Access Roads 1". During construction, the maximum climbing angle of the residual ore mining equipment is used. α Sink down along the slope until the top plate of "Secondary Access 3" is flush with the bottom plate of "Main Access 1", then advance in parallel until reaching the cutting level of "Main Access 1". During construction, the sinking sections of Connecting Road 2 and "Secondary Access 3" are supported by single-layer shotcrete mesh + steel arch frame (arch frame spacing 2m), and the parallel section of "Secondary Access 3" is supported by single-layer anchor shotcrete mesh. The cross-sectional specifications of Connecting Road 2 and "Secondary Access 3" only need to meet the minimum operating size of the residual ore recovery equipment. At the same time, complete the rock drilling of the fan-shaped blastholes of "Main Access 1" and "Secondary Access 3" in this area, so that the two blastholes are in the same vertical plane, and the step distance of ore collapse is maintained at 2m. Figure 3 , 4 and 5.

[0015] (3) After the grooving operation of main approach 1 is completed in the mining area, the mining operation of main approach 1 and secondary approach 3 will begin. During the operation, the two approaches will be withdrawn at the same time, but the adjacent "main approach 1" on the left and right needs to be one ore collapse step ahead of "secondary approach 3" so that peach-shaped pillars and ridge residues of "secondary approach 3" can be formed before the ore falls. When mining, "main approach 1" mines in a low-depletion manner, that is, mining stops when the waste rock arrives at the mine outlet normally during mining, while "secondary approach 3" mines in a cut-off grade manner.

[0016] (4) During the operation of the mining area, the preparation mining area actively completes the construction of the "secondary approach 3" in the area, and at the same time completes the rock drilling work of the "primary and secondary" approaches, and is ready to take over the mining operations of the mining area. After the mining of the mining area is completed, the preparation mining area is immediately converted into the mining area. At the same time, the preparation mining area is re-demarcated at the adjacent positions on the left and right of the new mining area to carry out preparation mining work. The two areas operate alternately in this way until the entire segmented mining is completed.

[0017] (5) The mining area and the preparation area are usually adjacent to each other on the plane and are rectangular in shape. The length along the approach direction is L From the sinking section of "Secondary Access 3" l1 and parallel segments l 2 consists of two parts, and the specific calculation formula is as follows: (1) Where: L It is the length of the mining area or the preparation area along the approach direction, in meters; l 1 is the plane length of the sinking section of "Secondary Approach 3", in meters; l 2 is the length of the parallel advancement section of “Secondary Approach 3”, in meters; h is the height of "Secondary Approach 3", in meters; α is the maximum climbing angle of the operating equipment in "Secondary Approach 3", α ; f It is the Proctor coefficient of the ore rock mass where the secondary approach 3 is located.

[0018] The width of the mining area and the preparation area in the vertical direction of the approach W The calculation formula is: (2) Where: W The width of the mining area or the preparation area in the vertical access direction, m; N The number of “main access roads 1” in the area is usually 3 to 6. f ≤4, N Take 3, when the rock Prototype coefficient is 4< f <6, N is taken as 4 at most. When the rock Prototype coefficient is 6≤ f <8 o'clock, N The maximum value is 5, when the rock Proctor coefficient f ≥8 o'clock, N The maximum value is 6; S is the spacing of “Main Approach 1”, and its value shall be subject to the actual design and construction, m.

Claims

1. A method for recovering residual ore in the last segment of a soft-broken thick and large ore body without a bottom pillar sublevel caving stope, characterized in that: In the final segmentation, the mining area and the preparation area are demarcated, and the operation tasks of each area are determined; The "main approach" and "secondary approach" are set up in the mining area, and mining is stopped at the same time to achieve full mining of the residual ore in the area to ensure the production capacity of the mining field; during the mining withdrawal process in the mining area, the preparation area completes the excavation and support of the "secondary approach" and the rock drilling of the blast holes of the "main and secondary" approaches to take over the mining operations in the mining area; After the mining area is withdrawn from mining, the preparation mining area is converted into the mining area. At the same time, the preparation mining area is re-demarcated in the adjacent areas on the left and right of the new mining area. The two areas are operated alternately in a cycle until the entire segment mining is completed, realizing the full mining of the residual ore in the last segment.

2. The method for recovering residual ore in the last segment of a soft-broken thick and large ore body without bottom pillars in a sublevel caving stope according to claim 1 is characterized in that: The "main approach" is a mining approach arranged in the mine according to conventional design, which is used to realize the conventional mining of the last segmented ore and ensure the mine production capacity; the "secondary approach" is a mining approach added between two adjacent "main approaches", and its task is to realize the full recovery of the peach-shaped pillars and residual ore on the ridge between the two adjacent "main approaches".

3. The method for recovering residual ore in the last segment of a soft-broken thick and large ore body without bottom pillars in a sublevel caving stope according to claim 1, characterized in that: The construction design method of the "secondary approach" in the mining preparation area is as follows: construct a horizontal connecting road at the end of the area to connect the main approaches in the area, and the end is based on the retreat direction. The bottom plate of the connecting road is at the same horizontal plane as the bottom plate of the main approach. In the connecting road, an opening is selected at the central position of the intermediate columns of two adjacent "main approaches" to construct the "secondary approach". During construction, the secondary approach is sunk according to the maximum climbing angle of the residual ore mining equipment until the top plate of the "secondary approach" is flush with the bottom plate of the "main approach" and then advanced in parallel, so that the "secondary approach" and the "main approach" are staggered in the horizontal direction, which is beneficial to improve the stability of the "secondary approach".

4. The method for recovering residual ore in the last segment of a soft-broken thick and large ore body without bottom pillars in a sublevel caving stope according to claim 3 is characterized in that: The sinking sections of the connecting road and the "secondary approach" are supported by a single-layer shotcrete mesh + steel arch frame, and the parallel section of the "secondary approach" is supported by a single-layer anchor shotcrete mesh.

5. The method for recovering residual ore in the last segment of a soft-broken thick and large ore body without bottom pillars in a sublevel caving stope according to claim 4, characterized in that: The cross-sectional specifications of the connecting road and "secondary access road" are 2.5~3.5m×2.5~3.5m.

6. The method for recovering residual ore in the last segment of a soft-broken thick and large ore body without bottom pillars in a sublevel caving stope according to claim 1, characterized in that: When the "main and secondary approaches" in the mining area are withdrawn at the same time, the adjacent "main approach" on the left and right must be 1~2 caving steps ahead of the "secondary approach" to facilitate the formation of peach-shaped ore pillars and ridge residues; the "secondary approach" uses upward fan-shaped blastholes to drop ore like the "main approach", and the caving step of the "secondary approach" is consistent with that of the "main approach", so that the two blasting rows are on the same vertical plane.

7. The method for recovering residual ore in the last segment of a soft-broken thick and large ore body without bottom pillars in a sublevel caving stope according to claim 6, characterized in that: When discharging ore, the "main route" is discharged in a low-depletion manner, that is, when the waste rock reaches the discharge port normally during the discharge process, the discharge is stopped, while the "secondary route" is discharged in a cut-off grade manner, so that more residual ore on the ridge can be retained in place, and finally discharged in the "secondary route" as pure ore, thereby improving the quality of ore recovery. By alternating the "main and secondary routes" in the mining area, the residual ore in the area can be fully recovered.

8. The method for recovering residual ore in the last segment of a soft-broken thick and large ore body without bottom pillars in a sublevel caving stope according to claim 1, characterized in that: The size of the mining area or the preparation area is determined by the length along the approach direction. L and the width in the vertical direction of the approach W Two parts determine the length L Length of the sinking section from the "secondary approach" l 1 and parallel segment length l 2. Two parts, the length of the sinking section l 1Depends on the maximum climbing angle of the residual ore recovery equipment α , parallel segment length l 2Depends on the Proctor coefficient of the ore rock f value, f The value is 20~60m, the worse the lithology, the smaller the value; width W The number of "main access roads" included in the mining area N and access distance S The product of N Take 3~6, ​​the worse the lithology N The smaller the value of .

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