A method of mining horizontal stage pillars left by a sublevel open stope followed by filling method

Abstract

The present application relates to a kind of stage empty field subsequent filling method horizontal stage pillar's stoping method, belong to mining engineering technical field.The present application is based on stage empty field subsequent filling method in steeply inclined thick ore body application, after upper and lower stage room stoping, filling is ended, to the peach-shaped pillar formed between stage top and bottom pillar and the "V" type groove between the bottom of adjacent two stope of upper stage using upward slicing drift filling method is stoped;In the bottom of upper stage, along the vein roadway and the horizontal vein roadway of lower stage cutting roof layer, according to 8%~13% slope, detour inclined ramp is excavated to slicing way and is stoped.The method of the present application is based on the upper and lower stage room stoping, filling is ended, and the stage top and bottom pillar and peach-shaped pillar are safely and efficiently stoped, to reduce the loss of ore, improve recovery rate.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of horizontal stage pillar of stage empty field subsequent filling method, belongs to mining engineering technical field. BACKGROUND

[0002] Stage empty field subsequent filling method in the mining of steeply inclined thick ore body, after the upper stage room mining ends, high cemented tailings filling is used in the top and bottom of room, low cemented tailings filling and non-cemented tailings filling are used in the middle of room according to I / II step room, high cemented filling is used in the lower part of room. When mining the lower stage room, if it is uninterrupted continuous mining with the upper stage room, when the upper stage mining and filling are completed, the bottom plate of "V" groove and peach-shaped pillar in the upper stage room will serve as the roof of the lower stage room, which will cause the large area exposure of the peach-shaped pillar and the filling body bottom plate in the bottom of the upper stage room, and the roof collapse of the lower stage room under the action of excavation disturbance stress. Therefore, a sufficient thickness of top and bottom pillars is reserved between the two stages to ensure the stability of the roof of the lower stage room. When the upper and lower stage rooms are mined, the top and bottom pillars between the two stages cannot be effectively and safely mined, resulting in ore loss. SUMMARY

[0003] To solve the problems of stage empty field subsequent filling method, such as ore loss caused by the ineffective and safe mining of the top and bottom pillars between the two stages and the peach-shaped pillars formed between the "V" grooves at the bottom of the two adjacent stope of the upper stage, the present application provides a mining method for the horizontal stage pillar reserved by stage empty field subsequent filling method, that is, the peach-shaped pillars formed between the horizontal top and bottom pillars between the stages and the "V" grooves at the bottom of the two adjacent stope of the upper stage are mined by upward slicing drift filling method; the along-vein drifts at the bottom of the upper stage and the along-vein drifts at the horizontal cutting level of the lower stage are excavated at an 8%~13% slope to the slicing drift for mining. Based on the mining and filling of the upper and lower stage rooms, the present application safely and efficiently mines the top and bottom pillars between the stages and the peach-shaped pillars to reduce ore loss and improve the recovery rate.

[0004] A mining method for stage pillars reserved by stage empty field subsequent filling method, the specific steps are as follows:

[0005] (1) Stope division of pillar mining: after the stage empty field subsequent filling method ends, the top and bottom pillars are formed between the two stages, the peach-shaped pillars are formed between the "V" grooves at the bottom of the two adjacent stope of the upper stage, and the top and bottom pillars and the peach-shaped pillars are horizontally layered in the vertical direction, and the I step and II step access type stope are vertically or staggered arranged along the ore body strike in each horizontal layer;

[0006] (2) Layout of mining preparation project: Horizontal stratification roadways are arranged along the strike of the ore body within the ore-rock boundary vein at the bottom of the stage top and bottom pillars and the bottom of the peach-shaped pillar. At the bottom of the upper stage, a bypass ramp is arranged along the vein transport roadway or the horizontal connecting roadway at the top of the lower stage at a slope of 8% to 13% every 45 to 55 m to the horizontal stratification roadway. The horizontal stratification roadway serves as a connecting roadway for the mining route. The horizontal stratification roadway connects two adjacent bypass ramps. As the mining layer rises, the bypass ramp is raised by brushing the top. The raised surrounding rock is raised and compacted to form the bypass ramp for the mining of the upper layer. Horizontal stratification roadways are arranged along the strike of the ore body within the vein.

[0007] (3) Mining and backfilling: Both the stage top and bottom pillars and the peach-shaped pillars are mined by upward-approaching layered mining. The stage top and bottom pillars are mined by using the upward bypass ramp arranged along the vein roadway of the next stage to reach the top and bottom pillars in layers. The peach-shaped pillars are mined by using the bottom vein roadway of the previous stage to reach the peach-shaped pillars in layers. Each layer is mined continuously according to the alternating arrangement of the first step and second step approaches. The first step approach stope is mined first, and cemented backfilling is carried out after the mining is completed. After the first step approach stope is mined and backfilled, the cemented backfilling is carried out. After the filling is completed and the curing period is reached, the adjacent II-step access stope is mined. After the mining is completed, the bottom layer is filled with non-cemented backfill and the surface layer is filled with cemented backfill. After the mining and backfilling of a layer is completed, the horizontal layering road of that layer is filled, the top of the bypass ramp outside the vein is brushed and raised, the collapsed rock debris is laid flat and compacted, and after construction to the ore body, the layering road is arranged along the strike of the ore body in the vein, rising to the next layer and mining the layering road layer by layer until the top of the peach-shaped pillar is mined.

[0008] The width and height of the access mining area in steps (1) I and II are 3~4m.

[0009] The slope of the bypass ramp in step (2) is 8% to 13%.

[0010] In step (3), each layer of the first step is first filled with a 2.5-3.5m thick layer of low-cement tailings sand, with a compressive strength of 1.0-1.5 MPa. Then, a 0.5-0.7m high-cement filling layer is applied to the top of the low-cement tailings sand filling, with a compressive strength of 1.5-2 MPa. In each layer of the second step, the bottom is filled with a 2.5-3.5m thick layer of non-cement tailings sand and waste rock, followed by a 0.5-0.7m high-cement filling layer with a compressive strength of 1.5-2 MPa. After one layer is mined, the next layer is filled with a 2.5-3.5m thick layer of low-cement filling, with a compressive strength of 1.0-1.5 MPa. Then, a 0.5-0.7m high-cement filling layer is applied to the top of the low-cement tailings sand filling. The high-cementation filling of the m-layer has a compressive strength of 1.5~2 MPa; the filling height of each layer's access road is consistent with the filling height of the layered approach stope.

[0011] The mining method for horizontal stage pillars left by the subsequent backfilling method in the open area of ​​this invention can be carried out by using a loader to extract ore, with appropriate additions to the preparatory work, and ore extraction can be carried out by using the existing ore extraction system; in areas or sections far from the ore pass, 15-20t trucks can be used in conjunction with loaders to extract ore.

[0012] In the method of this invention, if there is no residual ore on the ridge of the bottom "V"-shaped trench at the bottom of the stage stope, the filling body of the bottom "V"-shaped trench can be exposed when mining to the uppermost layer; if there is residual ore on the ridge of the bottom "V"-shaped trench at the bottom of the previous stage stope, the mining height of the approach corresponding to the bottom trench of the stope is reduced by 0.5~1m, so that a certain thickness of ore pillar is reserved in the middle to avoid the exposure of the residual ore on the ridge due to the exposure of the bottom "V"-shaped trench.

[0013] The method for mining horizontal stage pillars left by the subsequent backfilling method in the open area of ​​this invention adopts the upward layered approach backfilling method. The mining face is a single-ended roadway, and the approach uses a combination of extraction and pressure ventilation. Within the layer, a first-step approach stope is mined at certain intervals. At its end, a return air shaft is excavated to connect horizontally with the top cut-off layer of the next stage stope, so that the waste air is discharged to the top cut-off layer of the next stage stope and enters the original return air system. The second-step approach stopes on both sides of the first-step approach stope used for ventilation are not mined temporarily. After the mining and backfilling of the approach stopes in this area are completed, the second-step approach stopes on both sides are mined and backfilled.

[0014] The beneficial effects of this invention are:

[0015] (1) The method of the present invention is a mining method for the stage horizontal top and bottom pillars after the stage open space is filled in the steeply inclined ore body after mining is completed, under the premise of ensuring safety. It solves the permanent loss of stage top and bottom pillars caused by mining conditions and greatly improves the ore recovery rate.

[0016] (2) The width and height of the mining area in both Step I and Step II of this invention are 3~4m. When mining to the uppermost layer, the exposed area of ​​the bottom filling body of the upper stage stope is greatly reduced, ensuring the safety of mining. Attached Figure Description

[0017] Figure 1 This is a cross-sectional view along the strike of the ore body;

[0018] Figure 2 This is a cross-sectional view along the dip of the ore body;

[0019] In the diagram: 1 - Stage I cemented stope, 2 - Stage II uncemented stope, 3 - Stage stope bottom high-cemented backfill, 4 - Stage top and bottom pillars, 5 - Stage stope top high-cemented backfill, 6 - Stage bottom peach-shaped pillar, 7 - Stage I access stope for ventilation in the stage top and bottom pillars, 8 - External slope for roof lifting, 9 - External slope, 10 - Return air shaft, 11 - Stage stope top cut, 12 - Stage stope bottom ore access road, 13 - Stage along-vein roadway, 14 - Top cut along-vein roadway, 15 - Backfill retaining wall, 16 - Horizontal stratification roadway. Implementation

[0020] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the content described. Invention Overview

[0022] A method for mining horizontal stage pillars left by subsequent backfilling of staged open areas, the specific steps of which are as follows:

[0023] (1) Pillars and stope division: After the mining and filling of the upper and lower stages is completed, horizontal top and bottom pillars are formed between the two stages. Peach-shaped pillars are formed between the bottom "V" shaped grooves of the two adjacent stopes in the upper stage. The top and bottom pillars and peach-shaped pillars are horizontally layered in the vertical direction. In each horizontal layer, the I-step and II-step access stopes are arranged vertically or along the ore body strike. The width of the I-step and II-step access stopes is 3~5m and the height is 3~5m.

[0024] (2) Layout of mining preparation project: Horizontal stratification roadways are arranged along the strike of the ore body within the ore-rock boundary vein at the bottom of the stage top and bottom pillars and the bottom of the peach-shaped pillar. At the bottom of the upper stage along the vein transport roadway or the horizontal vein connecting roadway at the top of the lower stage, detour ramps are arranged every 50m at a slope of 8% to 13% to the horizontal stratification roadway. The horizontal stratification roadway serves as the connecting roadway for the mining route. The horizontal stratification roadway connects two adjacent detour ramps to form a complete ventilation system and two safety exits. As the mining layer rises, the detour ramp is raised by brushing the top. The raised surrounding rock is raised and compacted to form the detour ramp for the mining of the next layer.

[0025] (3) Mining and backfilling: The stage top and bottom pillars and the peach-shaped pillars are all mined by the upward approach in layers. The mining of the stage top and bottom pillars is carried out by the upward bypass ramp arranged along the vein roadway of the next stage cutting top layer to the top and bottom pillar layers. The peach-shaped pillars are mined by the bottom vein roadway of the previous stage to the peach-shaped pillar layers. Each layer is continuously mined by alternating the arrangement of the I-step and II-step approach mining areas. The I-step approach mining area is mined first, and cemented backfilling is carried out after the mining is completed. After the I-step mining area is mined and backfilling is completed and the curing age is reached, the II-step approach mining area is mined. After the mining is completed, non-cemented backfilling is carried out first, and cemented backfilling is carried out on the surface layer. After the mining and backfilling of one layer is completed, the horizontal layer roadway is backfilled according to the I-step approach mining area method. Then the bypass ramp is brushed and raised, and the rock slag and rock formation rises to the next layer and the upper layer is mined layer by layer until the top of the peach-shaped pillar is mined.

[0026] In each layer, step I of the approach first uses low-cement tailings sand to fill a 2.5-3.5m thick layer, with a compressive strength of 1-1.5 MPa. Then, a 0.5-0.7m high-cement layer is applied above the low-cement tailings sand, with a compressive strength of 1.5-2 MPa. In each layer, step II of the approach uses non-cement tailings sand and waste rock to fill a 2.5-3.5m thick layer at the bottom, followed by a 0.5-0.7m high-cement layer, with a compressive strength of 1.5-2 MPa. After one layer is mined, the approach roadway uses low-cement backfill to fill a 2.5-3.5m thick layer, with a compressive strength of 1-1.5 MPa. Then, a 0.5-0.7m high-cement layer is applied above the low-cement tailings sand. The high-cementation filling of the m-layer has a compressive strength of 1.5~2 MPa; the filling height of each layer's layer roadway is consistent with the filling height of the layered approach stope.

[0027] If there is no residual ore on the ridge of the "V"-shaped groove bottom plate of the stope, the filling body of the "V"-shaped groove bottom plate can be exposed when mining to the uppermost layer; if there is residual ore on the ridge of the "V"-shaped groove bottom plate of the stope, the mining height of the corresponding access road at the bottom of the stope should be reduced by 0.5~1m to leave a certain thickness of pillar in the middle, so as to avoid the exposure of residual ore on the ridge due to the exposure of the bottom "V"-shaped groove.

[0028] Example 1: A mine with an ore body dip of 70°~80° and a horizontal thickness of 45~55m is being mined using the staged open-stope backfilling method perpendicular to the ore body strike. The top and bottom of the stopes in steps I / II are filled with 1:4 cemented backfill, while the middle of the stopes is filled with 1:10 cemented backfill or non-cemented end sand and waste rock. There are no residual ore ridges at the bottom of the "V"-shaped troughs. There are horizontal top and bottom pillars with a thickness of 12m in the vertical direction between the stage stopes. Between the bottom "V"-shaped troughs of two adjacent stopes in the same stage, there are left top and bottom peach-shaped pillars with a vertical height of about 9.5m and a maximum bottom width of about 11m.

[0029] A method for mining horizontal stage pillars left by subsequent backfilling of staged open areas (see...) Figure 1 and 2 The specific steps are as follows:

[0030] (1) Division of pillars and mining areas: After the mining and filling of the upper and lower stages is completed, horizontal top and bottom pillars are formed between the two stages. Peach-shaped pillars are formed between the bottom "V" shaped grooves of the two adjacent mining areas in the upper stage. The top and bottom pillars and peach-shaped pillars are horizontally layered at a height of 4m in the vertical direction. In each horizontal layer, the I-step and II-step access mining areas are staggered along the ore body.

[0031] (2) Layout of mining preparation project: Horizontal stratification roadways are arranged along the strike of the ore body within the ore-rock boundary vein at the bottom of the stage top and bottom pillars and the bottom of the peach-shaped pillar. At the bottom of the upper stage, a bypass ramp is arranged along the vein transport roadway or the horizontal connecting roadway at the top of the lower stage with a slope of 8% to the horizontal stratification roadway. The horizontal stratification roadway serves as a connecting roadway for the mining route. The horizontal stratification roadway connects two adjacent bypass ramps. As the mining layer rises, the bypass ramp is raised by brushing the top. The raised surrounding rock is raised and compacted to form the bypass ramp for the mining of the upper layer. The bypass ramp is used for transportation, ventilation and backfilling.

[0032] (3) Mining of top and bottom pillars: Before mining in layers, a first-step access road type stope is excavated every 40 m. At the end of the stope, a return air shaft is excavated downward to the level of the next stage top layer to ensure ventilation in layers during mining. After the access road in this area is mined and backfilled, cemented backfilling is carried out, and then the second-step access roads on both sides are mined. Since the access road type stope is a single-headed roadway, pressure ventilation is adopted. Ore can be extracted by using the existing ore extraction system and layer connection.

[0033] (4) During layered mining, the first step of the access stope is mined first. After mining, a 4.5m thick layer of low-cement backfill with a compressive strength of 1~1.5 MPa is applied, followed by a 0.5m thick layer of high-cement backfill with a compressive strength of 1.5~2 MPa. Then, the second step of the access stope is mined. After mining, a 4.5m thick layer of uncemented tailings and waste rock is applied, followed by a 0.5m thick layer of high-cement backfill with a compressive strength of 1.5 MPa. ~2Mpa; After the layered approach stope is completed, the layered roadway is first filled with a 4.5m thick low cemented backfill, followed by a 0.5m thick high cemented backfill, with a compressive strength of 1.5~2Mpa; The 0.5m thick high cemented backfill provides the conditions for the operation of trackless equipment during the upper layered stope. After the end of one layered stope, the top of the bypass ramp is brushed and raised, and the collapsed ore is laid flat to raise the ramp, forming the ramp for the upper layered stope;

[0034] (5) The top and bottom pillars are mined according to the above steps. When the third layer is mined, there is no ridge residual ore at the bottom of the "V" shaped trough at the bottom of the upper stage stope. The corresponding I and II steps are mined at a height of 4m and filled with low cemented backfill or non-cemented tailings sand and waste rock at a height of 4m. The upper part of the I and II steps of the stope under the peach-shaped top and bottom pillars is still filled with 0.5m thick high cemented backfill to create conditions for subsequent mining.

[0035] (6) Mining of peach-shaped pillars: The peach-shaped pillars are located between the "V"-shaped troughs of two adjacent stopes in the previous stage. They are mined by an upward layered approach. The bottom plate of the approach stope is the same height as the bottom plate of the "V"-shaped trough. The peach-shaped pillars are mined upward in three layers. In the first layer, three approach routes are arranged. The middle one is the I-step approach, which is 3×4m high and wide. The two sides are the II-step approaches, which are 3×3m high and wide. In the second layer, one I-step approach and one II-step approach are arranged. Both are 3×3m high and wide. In the third layer, one II-step approach is arranged, which is 2.5×2.8m high and wide. The top and bottom pillars of the peach-shaped pillars are mined by a combined suction and pressure ventilation.

[0036] (7) When mining the top and bottom pillars of the peach-shaped mine in one layer, continuous mining is carried out in steps I and II by means of the bottom vein roadway of the stage. After the mining of step I, the bottom is filled with a 2.5m thick layer of low cemented backfill with a compressive strength of 1~1.5Mpa, and the surface layer is filled with a 0.5m thick layer of high cemented backfill with a compressive strength of 1.5~2Mpa. After the mining of step II, the bottom is filled with a 2.5m thick layer of tailings and waste rock non-cemented backfill, and the surface layer is filled with a 0.5m thick layer of high cemented backfill with a compressive strength of 1.5~2Mpa. Since the entry road of the first layer is at the same height as the ore exit roadway at the bottom of the stage stope, and the layout of the roadway will pass through the backfill body in the ore exit roadway, the ore and backfill body can be separated during mining.

[0037] (8) Arrange an external slope ramp along the vein to bypass the second layer of the layer, and continuously mine and fill the access stope in the order of step I and step II, and then carry out a 0.5m thick surface layer high cementation filling.

[0038] (9) After the second layer mining is completed, the top of the outer slope of the vein is raised and the fallen rock debris is compacted to form a slope to the third layer. The only second step of mining is carried out. After the mining is completed, the tailings and waste rock are filled into the full height of the roadway.

[0039] Example 2: A mine with an ore body dip of 70°~78° and a horizontal thickness of 35~45m is being mined using the staged open-stope backfilling method perpendicular to the ore body strike. In steps I / II, the top and bottom of the stopes are filled with 1:4 cemented backfill, while the middle of the stopes is filled with 1:10 cemented backfill or non-cemented end sand and waste rock. There are residual ore ridges at the bottom of the "V"-shaped troughs. In the vertical direction, 12m thick top and bottom pillars are left in the stage stopes. Between the bottom "V"-shaped troughs of two adjacent stopes in the same stage, there are lost peach-shaped top and bottom pillars with a vertical height of about 9.5m and a maximum bottom width of about 11m.

[0040] A method for mining horizontal stage pillars left by subsequent backfilling of staged open areas (see...) Figure 1 and 2 The specific steps are as follows:

[0041] (1) Pillar division: After the mining and filling of the two stages of the stage open area is completed, horizontal top and bottom pillars are formed between the two stages. Peach-shaped pillars are formed between the bottom "V" shaped grooves of the two adjacent stops in the upper stage. The top and bottom pillars and peach-shaped pillars are horizontally layered at a height of 4m in the vertical direction. In each horizontal layer, the I-step and II-step access stops are arranged vertically and alternately.

[0042] (2) Layout of mining preparation project: Horizontal stratification roadways are arranged along the strike of the ore body within the ore-rock boundary vein at the bottom of the stage top and bottom pillars and the bottom of the peach-shaped pillar. At the bottom of the upper stage, a bypass ramp is arranged along the vein transport roadway or the horizontal vein connecting roadway at the top of the lower stage with a slope of 10% to the horizontal stratification roadway. The horizontal stratification roadway serves as the connecting roadway for the mining route. The horizontal stratification roadway connects two adjacent bypass ramps. As the mining layer rises, the bypass ramp is raised by brushing the top. The raised surrounding rock is raised and compacted to form the bypass ramp for the mining of the upper layer. The bypass ramp is used for transportation, ventilation and backfilling.

[0043] (3) Mining of top and bottom pillars: Before mining in layers, a first-step access stop is excavated every 40 m. At the end of the access stop, a return air shaft is excavated downward to the level of the next stage top layer for ventilation during mining. After the access stop in this area is mined and backfilled, the first-step access stop used for ventilation is cemented and backfilled. Then the second-step access stops on both sides are mined. Since the access stop is a single-headed roadway, it adopts pressure ventilation. Ore can be extracted by means of the existing ore extraction system and the layered connection.

[0044] (4) During layered mining, the first step of the access stope is mined first. After mining, a 4.5m thick layer of low-cement backfill with a compressive strength of 1~1.5 MPa is applied, followed by a 0.5m thick layer of high-cement backfill with a compressive strength of 1.5~2 MPa. Then, the second step of the access stope is mined. After mining, a 3.5m thick layer of uncemented tailings and waste rock backfill is applied, followed by a 0.5m thick layer of high-cement backfill with a compressive strength of 1.5 MPa. ~2Mpa; After the layered approach stope is completed, the layered roadway is first filled with a 3.5m thick low-cemented backfill, followed by a 0.5m thick high-cemented backfill, with a compressive strength of 1.5~2Mpa; The 0.5m thick high-cemented backfill provides conditions for the operation of trackless equipment during the upper layered stope. After the end of one layered stope, the top of the bypass ramp is brushed and raised, and the collapsed rock debris is laid flat to raise the ramp, forming the ramp for the upper layered stope;

[0045] (5) When the top and bottom pillars are mined according to the above steps until the third layer is mined, there is residual ore at the bottom of the "V" shaped groove at the bottom of the upper stage stope. The corresponding I and II steps below it are mined at a height of 3m, and low-strength cemented backfill or non-cemented tailings sand and waste rock backfill is carried out at a height of 3m. The upper part of the I and II steps of the stope below the peach-shaped top and bottom pillars is still filled with 0.5m thick high cemented backfill to create conditions for subsequent mining.

[0046] (6) Mining of peach-shaped pillars: The peach-shaped pillars are located between the "V"-shaped troughs of two adjacent stopes in the previous stage. They are mined by an upward layered approach. The bottom plate of the approach stop is the same height as the bottom plate of the "V"-shaped trough. The peach-shaped pillars are mined upward in three layers. In the first layer, three approach stops are arranged. The middle one is the I-step approach, which is 3×4m high and wide. The two sides are the II-step approaches, which are 3×3m high and wide. In the second layer, one I-step approach and one II-step approach are arranged, which are both 3×3m high and wide. In the third layer, one II-step approach is arranged, which is 2.5×2.8m high and wide. When mining the top and bottom pillars of the peach-shaped pillars, a combined ventilation system is used.

[0047] (7) When mining the top and bottom pillars of the peach-shaped mine in one layer, continuous mining is carried out in steps I and II by means of the bottom vein roadway of the stage. After the mining of step I, the bottom is filled with a 2.5m thick layer of low cemented backfill with a compressive strength of 1~1.5Mpa, and the surface layer is filled with a 0.5m thick layer of high cemented backfill with a compressive strength of 1.5~2Mpa. After the mining of step II, the bottom is filled with a 2.5m thick layer of tailings and waste rock non-cemented backfill, and the surface layer is filled with a 0.5m thick layer of high cemented backfill with a compressive strength of 1.5~2Mpa. Since the entry road of the first layer is at the same height as the ore exit roadway at the bottom of the stage stope, and the layout of the roadway will pass through the backfill body in the ore exit roadway, the ore and backfill body can be separated during mining.

[0048] (8) Arrange an external slope ramp along the vein to bypass the second layer of the layer, and continuously mine and fill the access stope in the order of step I and step II, and then carry out a 0.5m thick surface layer high cementation filling.

[0049] (9) After the second layer mining is completed, the top of the outer slope of the vein is raised and the fallen rock debris is compacted to form a slope to the third layer. The only second step of mining is carried out. After the mining is completed, the tailings and waste rock are filled into the full height of the roadway.

[0050] The specific embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for mining horizontal stage pillars left by subsequent backfilling of staged open areas, characterized in that, The specific steps are as follows: (1) Division of the mining area for pillar mining: After the completion of the mining and filling of the upper and lower stages, horizontal top and bottom pillars are formed between the two stages in the stage open area subsequent filling method. Peach-shaped pillars are formed between the bottom "V" shaped grooves of the two adjacent mining areas in the upper stage. The top and bottom pillars and peach-shaped pillars are horizontally layered in the vertical direction. In each horizontal layer, the I-step and II-step access mining areas are arranged vertically or along the ore body strike. The width of the I-step and II-step access mining areas is 3~4m and the height is 3~4m. (2) Layout of mining preparation project: Horizontal stratification roadways are arranged along the strike of the ore body within the ore-rock boundary vein at the bottom of the stage top and bottom pillars and the bottom of the peach-shaped pillar. At the bottom of the upper stage, a bypass ramp is arranged along the vein transport roadway or the horizontal connecting roadway at the top of the lower stage with a slope of 8% to 13% to the horizontal stratification roadway. The horizontal stratification roadway serves as a connecting roadway for the mining route. The horizontal stratification roadway connects two adjacent bypass ramps. As the mining layer rises, the bypass ramp is raised by brushing the top. The raised surrounding rock is raised and compacted to form the bypass ramp for the mining of the upper layer. Horizontal stratification roadways are arranged along the strike of the ore body within the vein. (3) Mining and backfilling: The stage top and bottom pillars and the peach-shaped pillars are all mined by the upward approach in layers. The mining of the stage top and bottom pillars is carried out by the upward bypass ramp arranged along the vein roadway of the next stage cutting the top layer to the top and bottom pillar layers. The peach-shaped pillars are mined by the bottom vein roadway of the previous stage to the peach-shaped pillar layers. Each layer is continuously mined by alternating the arrangement of the I-step and II-step approach mining areas. The I-step approach mining area is mined first, and cemented backfilling is carried out after the mining is completed. After the I-step mining area is mined and backfilling is completed and the curing age is reached, the II-step approach mining area is mined. After the mining is completed, non-cemented backfilling is carried out first, and cemented backfilling is carried out on the surface layer. After the mining and backfilling of one layer is completed, the horizontal layer roadway is backfilled. The top of the bypass ramp is brushed and raised, the collapsed rock debris is compacted, and the horizontal layer roadway is arranged to the next layer and mined layer by layer upward until the top of the peach-shaped pillar is mined. Each of the aforementioned layered I steps first uses low-adhesion end sand to fill a bottom layer with a thickness of 2.5~3.5m, and then fills the top of the low-adhesion end sand filling body with a high-adhesion top layer of 0.5~0.7m.

2. The method for mining horizontal stage pillars left by the staged open area subsequent backfilling method according to claim 1, characterized in that: Step (2) The slope of the bypass ramp is 8%~13%.

3. The method for mining horizontal stage pillars left by the staged open area subsequent backfilling method according to claim 1, characterized in that: Step (3) The compressive strength of the low-cement tailing sand backfill in each layer I approach is 1~1.5 MPa, and the compressive strength of the high-cement backfill surface layer is 1.5~2 MPa; the bottom of each layer II approach is filled with non-cement tailing sand and waste rock for a thickness of 2.5~3.5 m, and then a 0.5~0.7 m high-cement backfill surface layer is carried out, with a compressive strength of 1.5~2 MPa; after the mining of one layer is completed, the layer roadway is filled with low-cement backfill for a bottom height of 2.5~3.5 m, with a compressive strength of 1~1.5 MPa, and then a 0.5~0.7 m high-cement backfill surface layer is carried out on the top of the low-cement tailing sand backfill, with a compressive strength of 1.5~2 MPa; the filling height of each layer roadway is consistent with the filling height of the layer approach stope.

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