Novel sill-pillar-free shallow hole shrinkage mining method with stud recovery

Abstract

The invention discloses a novel pillar-free shallow hole shrinkage mining method with stud recovery, which comprises the following steps of: stoping ore bodies from top to bottom, and stoping a to-be-mined room (9.1) and a to-be-mined stud (8.1) of a next middle section after stoping of the previous middle section of ore body is finished; a stoping stud (8.2) is communicated with an outside-vein pedestrian ventilation filling raise (6) arranged on a footwall surrounding rock (16) of an ore body through a stud connection way (5), the lower end of the outside-vein pedestrian ventilation filling raise (6) is communicated with the top of a middle section stud ore removal roadway (10), and the top end of the outside-vein pedestrian ventilation filling raise (6) is communicated with an upper middle section stud ore removal roadway (3). And the right end of the upper middle section column ore removal roadway (3) is communicated with the upper middle section haulage roadway (2). According to the method, the problems of large intermediate pillar ore loss and difficulty in recovery in a traditional shallow hole shrinkage method are solved, the resource recovery rate is increased to 88% or above, the compressive strength of the filled artificial intermediate pillar is superior to that of a primary pillar, and the stope stability is remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of underground mine mining, and specifically relates to a new non-bottom pillar shrinkage stoping mining method including the recovery of stulls, which is particularly suitable for the mining of medium-thick steeply inclined ore bodies with an ore body thickness of 3 - 8 m, an inclination angle of 50 - 85°, and medium or above ore-rock stability, and has particularly prominent advantages in the mining of high-grade precious metal ores, rare metal ores, and non-metallic ores such as fluorite. Background Art

[0002] As a widely used mining method in the field of underground mine mining, the shrinkage stoping method occupies an important position in the mining of precious metal ores, rare metal ores, and non-metallic ores such as fluorite by virtue of its relatively simple construction process. However, under the current industry background of increasingly stringent requirements for mine resource recovery rates, the disadvantages of the traditional shrinkage stoping method are gradually emerging, among which the problem of large ore losses is particularly prominent and urgent solutions are needed.

[0003] Traditional shrinkage stoping mining methods usually leave stulls, whose original intention is to support the ore chamber and ensure safety during the mining process. However, during normal mining, the ore in these stulls used for support often cannot be mined out, resulting in a large amount of permanent ore losses. Especially when the ore body has a high grade, high value, large scale, and a large number of ore chambers, the cumulative ore losses in the stulls are extremely serious, and the ore loss rate is as high as 15% - 30%. This not only significantly reduces the mine resource recovery rate but also causes a great waste of resources, having a serious negative impact on the economic benefits of mining enterprises. At the same time, in actual mine production, even if the stulls are specially recovered later, there are still intractable problems such as low recovery rate and high recovery dilution rate.

[0004] Chinese Patent CN202210861113.5 discloses a method for recovering stulls in a non-bottom pillar shrinkage stoping and subsequent filling mining method, and this method for recovering stulls includes the following steps:

[0005] d1) Drilling multiple rows of upwardly arranged shallow holes in each stull;

[0006] d2) Conducting sectional blasting and stoping for the stulls in the bottom row of the middle section. The blasted ore naturally falls to the out-of-reef haulage roadway in the footwall of the middle section and is removed by ore cars. After the ore removal is completed, steel pieces are inserted into the footwall and hanging wall surrounding rocks of this row of stulls to block the waste rock in the goaf;

[0007] d3) Repeating step d2) to complete the stoping and ore removal of all stulls from bottom to top;

[0008] d4) After the stoping and ore removal of all stulls are completed, non-cemented subsequent filling of the stull goaf with waste rock is carried out to control ground pressure, thereby completing the recovery of the crown pillar and stulls in the middle section.

[0009] Although this method can recover the remaining intermediate pillars, during the blasting and ore extraction processes, waste rock filling bodies are likely to mix into the ore body, resulting in an excessively high waste rock mixing rate. At the same time, after stoping, constructing steel members to isolate the waste rock filling stope on both sides has problems such as high construction difficulty, complex construction technology, and high construction costs. Summary of the Invention

[0010] The purpose of the present invention is to provide a new non-pillar shrinkage stoping method with intermediate pillar recovery that has a high resource recovery rate, high stope stability, and relatively simple construction technology, aiming at the serious ore loss and high dilution rate of intermediate pillar ore in the traditional shrinkage stoping method, as well as the problems of excessively high waste rock mixing rate, high construction difficulty, complex construction technology, and high construction costs in the subsequent filling mining method of non-pillar shrinkage stoping. Moreover, the compressive strength of the artificial intermediate pillar after filling is better than that of the original ore pillar.

[0011] To achieve the above object of the present invention, a new non-pillar shrinkage stoping method with intermediate pillar recovery of the present invention arranges the ore rooms and intermediate pillars to be mined in the middle section at intervals along the strike of the ore body; there are intermediate pillars being mined and intermediate pillar stope being filled on both sides of the ore room to be mined, and the upper part of the crown pillar of the ore room to be mined is the ore room that has been mined out in the upper middle section; the lower part of the intermediate pillar being mined is the ore stored in the intermediate pillar stope, and the upper part of the crown pillar of the intermediate pillar being mined and the intermediate pillar stope being filled is the intermediate pillar stope that has been filled in the upper middle section; the lower part of the ore room to be mined is the ore stored in the ore room, and the two sides are the intermediate pillar stopes that have been filled. Its characteristics are implemented by the following steps:

[0012] S1 Development Engineering Arrangement

[0013] 1.1) In the footwall surrounding rock of the ore body, construct a middle section haulage roadway along the strike direction of the ore body. The roadway section size of the middle section haulage roadway is: width 2.5 - 4.0 m, height 2.6 - 3.5 m, and the middle section haulage roadway is 5 - 15 m away from the ore body;

[0014] 1.2) Along the middle section haulage roadway, drive an ore draw roadway for the ore room vertically or obliquely at an angle of 45 - 60° every 5 - 6 m towards the ore room to be mined. The ore draw roadway for the ore room penetrates through the ore room to the contact surface between the ore body and the hanging wall surrounding rock; the net cross-sectional size of the ore draw roadway for the ore room is: width 2.2 - 3.0 m, height 2.4 - 3.0 m;

[0015] 1.3) Drive an ore draw roadway for the intermediate pillar vertically or obliquely towards the intermediate pillar to be mined along the middle section haulage roadway. The ore draw roadway for the intermediate pillar penetrates through the intermediate pillar to the contact surface between the ore body and the hanging wall surrounding rock; the net cross-sectional size of the ore draw roadway for the intermediate pillar is: width 2.2 - 3.0 m, height 2.4 - 3.0 m;

[0016] 1.4) In the hanging wall surrounding rock of the ore body within a range of 5 - 8 m below the footwall of the stope pillar 8.1 to be mined, construct an off-vein pedestrian ventilation raise upward along the roof of the stope draw roadway of the stope pillar. The dimensions of the off-vein pedestrian ventilation raise are: length 1.8 - 2.0 m, width 1.8 - 2.0 m; the slope of the off-vein pedestrian ventilation raise is the same as the dip angle of the ore body; the top end of the off-vein pedestrian ventilation and filling raise is connected to the stope draw roadway of the corresponding upper-level stope pillar, and the lower end of the off-vein pedestrian ventilation and filling raise is connected to the top of the stope draw roadway of this level. The right end of the stope draw roadway of the upper-level stope pillar is connected to the upper-level haulage roadway;

[0017] 1.5) Construct an intermediate pillar connection roadway perpendicular to the stope pillar to be mined every 3 - 5 m in the vertical direction of the off-vein pedestrian ventilation raise, and construct a stope connection roadway connecting the stopes on both sides of the stope pillar to be mined on both sides of the off-vein pedestrian ventilation raise respectively until the ore body is just exposed and stop without penetrating into the ore body; the intermediate pillar connection roadways and the stope connection roadways are arranged alternately, and the vertical distance between them is ≥1.5 m. The contact surface between the stope to be mined and the stope connection roadway is at least 2 m away from the boundary of the stope pillar to be mined; the cross-sectional dimensions of the intermediate pillar connection roadway are: width 1.8 - 2.0 m, height 2.0 - 2.2 m, length 5 - 8 m; the cross-sectional dimensions of the stope connection roadway are: width 1.8 - 2.0 m, height 2.0 - 2.2 m, length 5 - 8 m.

[0018] S2 Stope pillar extraction and filling

[0019] 2.1) Take the part of the stope draw roadway that penetrates into the stope pillar to be mined as the free face, and construct blast holes parallel to the dip angle of the ore body upward. The hole depth of the blast holes is 1.8 - 2.2 m, the hole spacing is 0.6 - 0.8 m, and the blast holes are arranged in a fan shape; load emulsion explosive into the blast holes, and conduct blasting extraction on the stope pillar to be mined. Initiate with a non-electric detonator initiation network, and use millisecond blasting with a delay error ≤25 ms to form the first-layer ore caving;

[0020] 2.2) After blasting, use a remote-controlled electric LHD to transport the ore stored in the stope of the stope pillar along the stope draw roadway to the surface. When the upper stacking elevation of the ore stored in the stope of the stope pillar is lowered to be flush with the bottom elevation of the first intermediate pillar connection roadway at the lower part of the stope pillar being mined, stop the LHD for ore extraction. At this time, a stope extraction space is formed between the ore stored in the stope of the stope pillar and the stope pillar being mined. This stope extraction space serves as the operation free face for the next-layer extraction blasting, and the ore stored in the stope of the stope pillar serves as the operation platform for the next layer, and at the same time plays a role in supporting the hanging wall and footwall surrounding rocks of the stope of the stope pillar and maintaining the stability of the stope;

[0021] 2.3) From the stope draw roadway → off-vein pedestrian ventilation raise → intermediate pillar connection roadway → stope extraction space, extract the stope pillar being mined layer by layer upward; after each layer of blasting, use a forced local ventilator (power about 5.5 kW, air volume ≥200 m 3It is extracted by exhaust ventilation (at a rate of / min) and discharged to the surface;

[0022] 2.4) Repeat the above steps 2.2) to 2.3) until the stope of the pillar being mined reaches the level of the crown pillar; after the mining is completed, the stope of the pillar being mined is filled with ore. A remote-controlled LHD (load capacity ≥ 6t) is used to centrally load and transport the ore at the ore-drawing roadway at the bottom of the pillar being mined. The ore shoveled out is transported through the ore-drawing roadway of the pillar and loaded into the ore car in the haulage roadway of this level, and then the ore car is towed by an electric locomotive to transport the ore to the main shaft or out of the surface through an adit.

[0023] 2.5) After the ore drawing of the pillar being mined is completed, high-density polyethylene pipes are laid from the haulage roadway of the upper level → the ore-drawing roadway of the upper-level pillar → the crosscut ventilation raise outside the vein → the pillar connecting roadway. When backfilling the stope of the pillar being backfilled, it is backfilled in layers from bottom to top; a backfill retaining wall is constructed at each filling height in front of the pillar connecting roadway to block the pillar connecting roadway; when filling to the top, pressure grouting is carried out to ensure that the roof contact rate ≥ 95%, so as to ensure the quality of the backfill roof and form the stope of the pillar that has been backfilled.

[0024] S3 Stope Mining

[0025] 3.1) After all the pillars to be mined and the pillars being mined in this level are mined and backfilled, or when there are more than 2 unmined stopes ahead of the stope of the pillar that has been backfilled, then the unmined stope is mined; when mining the unmined stope, taking the part of the space in the ore-drawing roadway of the stope entering the unmined stope as the free face, a cut roadway is constructed along the length direction of the unmined stope. Wedge-shaped cut is used for the blasting of the cut roadway, the dip angle of the cut holes is 55° - 65°, the spacing of the auxiliary holes ≤ 0.8m, the spacing of the perimeter holes ≤ 0.5m respectively, the charging coefficient of the perimeter holes ≤ 0.6, and the thickness of the remaining smooth blasting layer ≥ 200mm; the formed cut roadway is used as the blasting and mining space for blasting and mining; emulsion explosive and non-electric detonating tube are used for blasting, and blasting is carried out once for each completed bench working face.

[0026] 3.2) After the blasting is completed, local ore drawing is carried out for the ore stored in the stope; a remote-controlled electric LHD is used to load and transport the ore stored in the stope along the ore-drawing roadway of the stope. When the upper storage elevation of the ore stored in the stope is lowered to a distance of 1.8 - 2.0m from the stope being mined in the vertical direction, the loading and transportation of the ore stops; at this time, a stope mining space with a height of 1.8 - 2.0m is formed between the ore stored in the stope and the stope being mined, which is convenient for the next cycle operation. The stope mining space is used as the operation free face for the blasting of the next bench mining of the stope being mined; the remaining ore stored in the stope is used as the next drilling working platform.

[0027] 3.3) Before the staff enter the mining space of the ore room for construction, mechanical ventilation shall be carried out on the ore room being mined; an exhaust type local ventilator shall be installed in the ore room connecting drift on the other side of the ore room being mined, and the fresh air flow shall enter the mining space of the ore room through the ore room connecting drift from the crosscut ventilation raise outside the vein. After flushing the working face, the polluted air shall flow into the upper section haulage roadway through the ore room connecting drift on the other side of the ore body and the crosscut ventilation raise outside the vein and be discharged to the surface;

[0028] 3.4) To facilitate the workers to carry out rock drilling and blasting operations on the reserved ore in the ore room, the surface of the remaining reserved ore in the ore room shall be leveled after partial ore drawing; during the leveling operation, the loosened but not fallen ore and rock on the roof and two sides shall be pried down to ensure the safety of subsequent operations; the large blocks fallen during ore caving and roof prying shall be broken during the leveling operation to facilitate ore drawing;

[0029] 3.5) Repeat the above steps 3.1) to 3.4) until all the remaining reserved ore in the ore room is discharged at one time when the ore room being mined reaches the top pillar; the ore is transported from the ore drawing roadway of the ore room to the haulage roadway of the section for loading and then transported to the surface; after the final ore drawing is completed, the stope shall be completely closed in time to prevent personnel from straying in and is also beneficial to the mine ventilation.

[0030] Further, the ore body is mined from top to bottom, divided into several sections with a section height of 30 - 60m. The ore rooms to be mined and the intermediate pillars to be mined in each section are arranged along the strike of the ore body; the width of the ore room to be mined is the same as the thickness of the ore body, the length of the ore block is 40 - 60m, and the height is 30 - 60m; the length of the top pillar is 40 - 60m, the height is 4 - 8m, and its width is the same as the thickness of the ore body; the width of the intermediate pillar to be mined is 6 - 10m, the height is 30 - 60m, and its width is the same as the thickness of the ore body.

[0031] Further, the ore drawing roadway of the ore room is located at the lower part of the reserved ore in the ore room, and the right end of the ore drawing roadway of the ore room is connected to the haulage roadway of the section.

[0032] Further, the intermediate pillar being mined is connected to the crosscut ventilation and filling raise in the country rock of the footwall of the ore body through the intermediate pillar connecting drift.

[0033] Further, in step 2.3), the fresh air flow is through a forced ventilation local ventilator, and through the pipeline from the haulage roadway of the section → the intermediate pillar ore drawing roadway → the crosscut ventilation raise outside the vein → the intermediate pillar connecting drift → the mining space of the intermediate pillar stope. The polluted air generated is forced out and then flows from the intermediate pillar connecting drift → the crosscut ventilation raise outside the vein → the intermediate pillar ore drawing roadway of the upper section → the haulage roadway of the upper section → the surface.

[0034] Further, the filled intermediate pillar stope is closed with a filling retaining wall for the intermediate pillar ore drawing roadway and the intermediate pillar connecting drift.

[0035] Further, in step 3.1), when the width of the ore room to be mined is less than 3 m, the width of the cutting roadway is the width of the ore room to be mined; when the width of the ore room to be mined exceeds 3 m, the width of the cutting roadway is 2 - 3 m; the height of the cutting roadway is 2 - 4 m, and the length is the length of the ore room to be mined.

[0036] Further, in step 3.2), when partially extracting the ore stored in the ore room, the extraction amount each time is 30% - 35% of the blasting amount, and the remaining ore stored in the ore room serves as the next drilling work platform.

[0037] Further, in step 3.3), after the concentration of harmful substances in the ore room being mined reaches the allowable value, the staff can enter the mining space of the ore room for construction.

[0038] Further, the interval between the upper-level haulage roadways is 5 - 6 m, and construction is carried out in a vertical or obliquely intersecting direction at 45 - 60°, and construction stops when it penetrates the contact surface between the mined-out ore room in the upper level and the newly exposed ore body in the hanging wall rock.

[0039] A new non-pillar shrinkage stoping method with pillar recovery in the present invention adopts the arrangement of crosscut raises outside the vein. By taking measures such as adding pillar connecting roadways and ore room connecting roadways, first the pillar is mined and backfilled as a small stope, and finally the ore room is mined, solving the problems of high ore loss rate and difficult pillar recovery in the traditional shrinkage stoping method, and realizing the safe mining of the ore room stope. Specifically, it has the following positive effects:

[0040] (1) Significantly improves the recovery rate of mineral resources. By effectively recovering the pillars, resource waste is reduced, and the economic benefits of the mine are increased.

[0041] (2) The backfilled pillar after mining replaces the original pillar to maintain safety and stability. Moreover, compared with the ore pillar, the artificially cast artificial pillar has more prominent advantages in maintaining the stability of the stope.

[0042] (3) The innovative technical process of first mining the pillar and then the ore room in the present invention solves the thorny problems such as difficult recovery and low recovery rate in the traditional shrinkage stoping method when specifically recovering the pillar later.

[0043] (4) The crosscut raise outside the lower vein will not be mined out due to the mining of the pillar. After the stope mining is completed, it can still play the role of connecting the upper and lower levels, ensuring the integrity of the ventilation and other systems between the middle levels of the mine. Description of the Drawings

[0044] Figure 1 It is the front view of the development engineering layout in a new non-pillar shrinkage stoping method with pillar recovery.

[0045] Figure 2 The front view of the extraction and filling of the middle pillar in a new non-bottom pillar shrinkage stoping method with intermediate pillar recovery of the present invention;

[0046] Figure 3 is Figure 2 the side view of the A-A section in

[0047] Figure 4 is Figure 2 the side view of the B-B section in

[0048] Figure 5 is Figure 2 the top view of the C-C section in

[0049] Figure 6 The front view of the extraction of the middle ore chamber in a new non-bottom pillar shrinkage stoping method with intermediate pillar recovery of the present invention;

[0050] Figure 7 is Figure 6 the side view of the D-D section in

[0051] Figure 8 is Figure 6 the side view of the E-E section in

[0052] Figure 9 is Figure 6 the top view of the F-F section in

[0053] The markings in the figure are: 1 - the filled intermediate pillar stope in the upper level; 2 - the upper level haulage roadway; 3 - the intermediate pillar ore-drawing roadway in the upper level; 4 - the top pillar; 5 - the intermediate pillar connection roadway; 6 - the cross-cut for personnel and ventilation outside the vein; 7 - the ore chamber connection roadway; 8.1 - the intermediate pillar to be mined; 8.2 - the intermediate pillar being mined; 8.3 - the intermediate pillar stope being filled; 8.4 - the intermediate pillar stope that has been filled; 9.1 - the ore chamber to be mined; 9.2 - the ore chamber being mined; 9.3 - the ore chamber that has been mined; 10 - the intermediate pillar ore-drawing roadway; 11 - the ore chamber ore-drawing roadway; 12 - the blast hole; 13 - the extraction space of the intermediate pillar stope; 14 - the reserved ore in the intermediate pillar stope; 15 - the filling retaining wall; 16 - the footwall surrounding rock of the ore body; 17 - the level haulage roadway; 18 - the contact surface between the ore body and the hanging wall surrounding rock; 19 - the extraction space of the ore chamber; 20 - the reserved ore in the ore chamber; 21 - the ore chamber ore-drawing roadway in the upper level; 22 - the cut roadway. Detailed implementation manners

[0054] To better describe the present invention, the following further describes in detail a new non-bottom pillar shrinkage stoping method with intermediate pillar recovery of the present invention in conjunction with the accompanying drawings.

[0055] From Figure 1As can be seen from the front view of the development engineering layout in a new non-bottom pillar shrinkage stoping method with intermediate pillar recovery shown in the figure, the ore body is mined in the order from top to bottom. After the mining of the ore body in the upper middle section is completed, the ore rooms 9.1 and intermediate pillars 8.1 to be mined in the lower middle section are then mined. The ore rooms 9.1 and intermediate pillars 8.1 to be mined within the middle section are arranged at intervals along the strike of the ore body.

[0056] From Figure 2 the front view of the intermediate pillar mining and backfilling in a new non-bottom pillar shrinkage stoping method with intermediate pillar recovery shown in the figure and in combination with Figure 3 , Figure 4 , Figure 5 it can be seen that on both sides of the ore room 9.1 to be mined, there are intermediate pillars 8.2 being mined and stope 8.3 of intermediate pillar being backfilled. Above the top pillar 4 of the ore room 9.1 to be mined is the ore room 9.3 where the mining has been completed. Above the top pillar 4 of the intermediate pillar 8.2 being mined and stope 8.3 of intermediate pillar being backfilled is the stope 1 of the intermediate pillar in the upper middle section that has been backfilled. The intermediate pillar 8.2 being mined is connected to the off-vein pedestrian ventilation and backfilling raise 6 arranged in the footwall surrounding rock 16 of the ore body through the intermediate pillar connecting roadway 5. The lower end of the off-vein pedestrian ventilation and backfilling raise 6 is connected to the top of the intermediate pillar ore-drawing roadway 10 in this middle section, and the top end is connected to the intermediate pillar ore-drawing roadway 3 in the upper middle section. The right end of the intermediate pillar ore-drawing roadway 3 in the upper middle section is connected to the upper middle section haulage roadway 2. Below the intermediate pillar 8.2 being mined is the ore stored in the stope of the intermediate pillar 14, and below the ore stored in the stope of the intermediate pillar 14 is the intermediate pillar ore-drawing roadway 10. The right end of the intermediate pillar ore-drawing roadway 10 is connected to the middle section haulage roadway 17.

[0057] From Figure 6 the front view of the ore room mining in a new non-bottom pillar shrinkage stoping method with intermediate pillar recovery shown in the figure and in combination with Figure 7 , Figure 8 , Figure 9 it can be seen that below the ore room 9.1 to be mined is the ore stored in the ore room 20, and on both sides are the stopes 8.4 of the intermediate pillar that have been backfilled. Below the ore stored in the ore room 20 is the ore-drawing roadway 11 of the ore room. The right end of the ore-drawing roadway 11 of the ore room is connected to the middle section haulage roadway 17. The stopes 8.4 of the intermediate pillar that have been backfilled are closed with a backfill retaining wall 15 together with the intermediate pillar ore-drawing roadway 10 and the intermediate pillar connecting roadway 5.

[0058] In combination with Figures 1 - 8, In the embodiment, for a new non-pillar shrinkage stoping method with extraction of intermediate pillars in the present invention, the ore body is mined from top to bottom, divided into several levels with a level height of 30 - 60 m. In each level, the ore rooms 9.1 to be mined and the intermediate pillars 8.1 to be mined are arranged along the strike of the ore body; the width of the ore room 9.1 to be mined is the same as the thickness of the ore body, the length of the ore block is 40 - 60 m, and the height is 30 - 60 m; the length of the top pillar 4 is 40 - 60 m, the height is 4 - 8 m, and its width is the same as the thickness of the ore body; the width of the intermediate pillar 8.1 to be mined is 6 - 10 m, the height is 30 - 60 m, and its width is the same as the thickness of the ore body. The following technological steps are specifically adopted:

[0059] 1) In the footwall surrounding rock 16 of the ore body, a level haulage roadway 17 is constructed along the strike direction of the ore body. The cross-sectional dimensions of the level haulage roadway 17 are: width 2.5 - 4.0 m, height 2.6 - 3.5 m, and the level haulage roadway 17 is 5 - 15 m away from the ore body.

[0060] 2) Along the level haulage roadway 17, an ore pass 11 is driven vertically or obliquely at an angle of 45 - 60° every 5 - 6 m towards the ore room 9.1 to be mined. The ore pass 11 penetrates through the ore room 9.1 to be mined to the contact surface 18 between the ore body and the hanging wall surrounding rock; the net cross-sectional dimensions of the ore pass 11 are: width 2.2 - 3.0 m, height 2.4 - 3.0 m.

[0061] 3) A pillar ore pass 10 is driven vertically or obliquely along the level haulage roadway 17 towards the intermediate pillar 8.1 to be mined. The pillar ore pass 10 penetrates through the intermediate pillar 8.1 to be mined to the contact surface 18 between the ore body and the hanging wall surrounding rock; the net cross-sectional dimensions of the pillar ore pass 10 are: width 2.2 - 3.0 m, height 2.4 - 3.0 m.

[0062] 4) In the footwall surrounding rock 16 of the ore body within a range of 5 - 8 m below the intermediate pillar 8.1 to be mined, an off-vein pedestrian ventilation raise 6 is constructed upwards along the roof of the pillar ore pass 10. The dimensions of the off-vein pedestrian ventilation raise 6 are: length 1.8 - 2.0 m, width 1.8 - 2.0 m; the slope of the off-vein pedestrian ventilation raise 6 is the same as the dip angle of the ore body, usually 60° - 80°; the top of the off-vein pedestrian ventilation and filling raise 6 is connected to the corresponding upper-level pillar ore pass 3, the lower end of the off-vein pedestrian ventilation and filling raise 6 is connected to the top of the pillar ore pass 10 of this level, and the right end of the upper-level pillar ore pass 3 is connected to the upper-level haulage roadway 2; steel ladders and safety fences are installed in the off-vein pedestrian ventilation raise 6 to ensure the safety of personnel passage.

[0063] 5) At intervals of 3 - 5 m in the vertical direction of the out - vein pedestrian ventilation raise 6, construct an intermediate pillar connection drift 5 perpendicular to the to - be - mined intermediate pillar 8.1, and construct a stope connection drift 7 connecting the two sides of the to - be - mined stope 9.1 on both sides of the out - vein pedestrian ventilation raise 6 until just exposing the ore body, without penetrating the ore body; the intermediate pillar connection drift 5 and the stope connection drift 7 are arranged staggeredly, and their vertical spacing is ≥1.5 m; the contact surface of the stope connection drift 7 with the to - be - mined stope 9.1 is at least 2 m away from the boundary of the to - be - mined intermediate pillar 8.1; the cross - section size of the intermediate pillar connection drift 5 is: width 1.8 - 2.0 m, height 2.0 - 2.2 m, length 5 - 8 m; the cross - section size of the stope connection drift 7 is: width 1.8 - 2.0 m, height 2.0 - 2.2 m, length 5 - 8 m.

[0064] 6) Take the part of the intermediate pillar ore - drawing drift 10 that penetrates into the to - be - mined intermediate pillar 8.1 as the free face, and construct upward blast holes 12 parallel to the dip angle of the ore body, with a hole diameter of 42 mm; the blast holes 12 are arranged in a fan - shaped pattern, the hole depth of the blast holes 12 is 1.8 - 2.2 m, the hole spacing is 0.6 - 0.8 m, and emulsion explosive (density 1.1 g / cm 3 ) is loaded into the blast holes 12, the explosive specific consumption is 0.3 - 0.4 kg / t, and it is detonated by a non - electric detonator initiation network, using millisecond blasting with a millisecond interval of 25 ms.

[0065] 7) After blasting, use a remote - controlled electric LHD to transport part of the reserved ore 14 in the intermediate pillar stope along the intermediate pillar ore - drawing drift 10. When the upper stacking elevation of the reserved ore 14 in the intermediate pillar stope is lowered to be flush with the bottom elevation of the first intermediate pillar connection drift 5 at the lower part of the intermediate pillar 8.2 being mined, stop the ore - drawing operation. At this time, a mining space 13 of the intermediate pillar stope is formed between the reserved ore 14 in the intermediate pillar stope and the intermediate pillar 8.2 being mined. This mining space 13 of the intermediate pillar stope serves as the operation free face for the next - layer mining blasting, and the reserved ore 14 in the intermediate pillar stope serves as the operation platform for the next - layer operation.

[0066] 8) From the intermediate pillar ore - drawing drift 10 → out - vein pedestrian ventilation raise 6 → intermediate pillar connection drift 5 → mining space 13 of the intermediate pillar stope, mine the intermediate pillar 8.2 being mined layer by layer upward; after each - layer blasting, the fresh air flow is through a forced - ventilation local fan (power 5.5 kW, air volume ≥200 m 3 / min), and through the pipeline from the cross - cut transportation roadway 17 → intermediate pillar ore - drawing drift 10 → out - vein pedestrian ventilation raise 6 → intermediate pillar connection drift 5 → mining space 13 of the intermediate pillar stope. The generated polluted air is forced out and then discharged from the intermediate pillar connection drift 5 → out - vein pedestrian ventilation raise 6 → upper - level intermediate pillar ore - drawing drift 3 → upper - level transportation roadway 2 → surface according to the ventilation sequence.

[0067] 9) Repeat the above steps 7) - 8) until the extraction of the stope pillar 8.2 being mined reaches the level of the crown pillar 4; after the extraction is completed, use a remote-controlled load-haul-dump (LHD) vehicle (load capacity ≥ 6t) to conduct centralized scraping and hauling of ore in the ore-drawing roadway 10 at the bottom of the stope pillar 8.2 being mined.

[0068] 10) After the ore extraction of the stope pillar 8.2 being mined is completed, lay Φ150mm high-density polyethylene pipes from the upper-level haulage roadway 2 → the upper-level stope pillar ore-drawing roadway 3 → the cross-cut ventilation raise 6 outside the vein → the stope pillar connecting roadway 5. When backfilling the stope 8.3 of the stope pillar being filled, conduct layered backfilling from bottom to top, with each layer having a height of 3m; construct a backfill retaining wall 15 before each filling height reaches the stope pillar connecting roadway 5. The backfill retaining wall 15 is made of C25 quick-setting concrete (with a quick-setting agent dosage of 3%), with a thickness of 0.5m and an internal Φ8mm steel mesh (spacing 200mm); when backfilling to the top, apply pressure grouting to ensure a contact ratio of ≥ 95% to form the backfilled stope 8.4 of the stope pillar; the backfill material is a mixture of classified tailings (particle size ≤ 5mm) and ordinary Portland cement (PO42.5), with a cement-sand ratio of 1:8 and a concentration of 70%, and the 28-day compressive strength of the backfill body ≥ 1.5MPa.

[0069] 11) After the extraction and backfilling of all the stope pillars 8.1 to be mined and the stope pillar 8.2 being mined in this level are completed, or when there are more than 2 unmined stopes 9.1 before the backfilled stope 8.4 of the stope pillar, then mine the unmined stope 9.1; when mining the unmined stope 9.1, use the part of the space in the ore-drawing roadway 11 of the stope as the free face, and construct a cut roadway 22 along the length direction of the unmined stope 9.1. The cut roadway 22 is blasted using a wedge cut, with the inclination angle of the cut holes being 55° - 65°, the spacing of the auxiliary holes ≤ 0.8m, the spacing of the perimeter holes ≤ 0.5m respectively, the charging coefficient of the perimeter holes ≤ 0.6, and the reserved smooth blasting layer thickness ≥ 200mm; conduct blasting extraction using the formed cut roadway 22 as the blasting extraction space; the blasting uses emulsion explosives and non-electric detonating tubes for initiation, and one blasting is carried out for each completed bench working face. When the width of the unmined stope 9.1 is less than 3m, the width of the cut roadway 22 is the width of the unmined stope 9.1; when the width of the unmined stope 9.1 exceeds 3m, the width of the cut roadway 22 is 2 - 3m; the height of the cut roadway 22 is 2 - 4m, and the length is the length of the unmined stope 9.1.

[0070] 12) After blasting is completed, partial ore extraction is carried out on the ore reserved in the stope 20; a remotely controlled electric LHD is used to load and transport the ore reserved in the stope 20 along the stope ore extraction roadway 11. When the upper stacking elevation of the ore reserved in the stope 20 is lowered to a distance of 1.8 - 2.0 m from the corresponding stope 9.2 being mined in the vertical direction, the ore extraction is stopped; at this time, a stope mining space 19 with a height of 1.8 - 2.0 m is formed between the ore reserved in the stope 20 and the stope 9.2 being mined. The stope mining space 19 serves as the working free face for the next bench blasting in the stope 9.2 being mined; the remaining ore reserved in the stope 20 serves as the next drilling platform. When carrying out partial ore extraction of the ore reserved in the stope 20, the amount of ore extracted each time is 30% - 35% (about one-third) of the blasted amount.

[0071] 13) Before the staff enters the stope mining space 19 for construction, mechanical ventilation needs to be carried out on the stope 9.2 being mined; an exhaust type local ventilator is installed in the stope connection roadway 7 on the other side of the stope 9.2 being mined. Fresh air flows from the off-vein pedestrian ventilation raise 6 through the stope connection roadway 7 into the stope mining space 19. After flushing the working face, the polluted air is discharged to the surface through the stope connection roadway 7 on the other side of the ore body and the off-vein pedestrian ventilation raise 6 into the upper section haulage roadway 2. After the concentration of harmful substances in the stope 9.2 being mined reaches the allowable value, the staff can enter the stope mining space 19 for construction.

[0072] 14) To facilitate the drilling and blasting operations of workers on the ore reserved in the stope 20, the surface of the remaining ore reserved in the stope 20 should be leveled after partial ore drawing; during the bench leveling, the loosened but not fallen ore and rock on the roof and two sides should be pried down to ensure the safety of subsequent operations; the large pieces that fall during ore caving and roof prying should be broken during bench leveling to facilitate ore extraction.

[0073] 15) Repeat the above steps 11) - 14) until all the remaining ore reserved in the stope 20 is discharged at one time when the stope 9.2 being mined reaches the crown pillar 4; the ore is transported from the stope ore extraction roadway 11 to the middle section haulage roadway 17, loaded and transported to the surface; after the final ore extraction is completed, the stope should be completely closed in time to prevent personnel from straying in and is also beneficial to the ventilation of the mine.

[0074] In addition, the layout form of the upper section ore extraction roadway 21 is the same as that of the stope ore extraction roadway 11: the interval between the upper section haulage roadways 2 is also 5 - 6 m, and construction is carried out in a vertical or oblique intersection direction of 45 - 60°. Construction stops when it penetrates the contact surface 18 between the ore body just exposed in the mined-out stope 9.3 in the upper section and the hanging wall rock. In the vertical projection direction, the upper section ore extraction roadway 21 corresponds one by one to the stope ore extraction roadway 11. The net cross-sectional size of the upper section ore extraction roadway 21 is 2.2 - 3.0 m (width) × 2.4 - 3.0 m (height).

[0075] The method of the present invention solves the problems of large ore loss (loss rate 15% - 30%) and difficult recovery in the middle pillar in the traditional shrinkage stoping method by arranging out-of-vein pedestrian ventilation raises, adding crosscuts between middle pillars and crosscuts between ore rooms, preferentially mining and backfilling the middle pillar as an independent stope, and then mining the ore room. By replacing the ore middle pillar with a filled artificial middle pillar, the resource recovery rate of the present invention is increased to over 88%. The compressive strength of the filled artificial middle pillar is better than that of the original ore pillar, and the stope stability is significantly improved. The present invention is applicable to the efficient mining of medium-thick steeply inclined ore bodies such as precious metal ores, rare metal ores, and fluorite. The specific steps include: construction of the middle-level haulage roadway and ore-drawing roadway, driving of out-of-vein pedestrian ventilation raises, crosscuts between middle pillars and crosscuts between ore rooms, bench blasting and mining of the middle pillar, filling operation, and mining of the ore room.

[0076] The present invention has been successfully applied to the mining of a new shrinkage stoping method in a gold mine. According to statistics, using the present invention can increase the recovery rate of the middle pillar to over 88%, generating an economic benefit of more than 18 million yuan per year; and the compressive strength of the filled artificial middle pillar is better than that of the original ore pillar, effectively improving the stope safety.

[0077] It should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front", "rear", "top / bottom end", etc. of the present invention is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description. Therefore, it should not be construed as a limitation of the present invention.

[0078] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent replacements or changes should be covered within the protection scope of the present invention.

Claims

1. A new non-pillar shrinkage stoping method with recovery of intermediate pillars. The ore rooms (9.1) to be mined and the intermediate pillars (8.1) to be mined in the middle section are arranged at intervals along the strike of the ore body. Intermediate pillars (8.2) being mined and intermediate pillar stopes (8.3) being filled are provided on both sides of the ore room (9.1) to be mined. Above the top pillar (4) of the ore room (9.1) to be mined is the ore room (9.3) in the upper middle section where mining has been completed. Below the intermediate pillar (8.2) being mined is the ore stored in the intermediate pillar stope (14). Above the top pillar (4) of the intermediate pillar (8.2) being mined and the intermediate pillar stope (8.3) being filled is the intermediate pillar stope (1) in the upper middle section that has been filled. Below the ore room (9.1) to be mined is the ore stored in the ore room (20), and on both sides are the intermediate pillar stopes (8.4) that have been filled. It is characterized in that It is implemented by the following steps: S1 Development engineering layout 1.1) In the footwall surrounding rock (16) of the ore body, a crosscut haulage roadway (17) is constructed along the strike direction of the ore body. The roadway section size of the crosscut haulage roadway (17) is: width 2.5 - 4.0 m, height 2.6 - 3.5 m, and the crosscut haulage roadway (17) is 5 - 15 m away from the ore body; 1.2) Along the crosscut haulage roadway (17), an ore pass (11) is driven vertically or obliquely at an angle of 45 - 60° every 5 - 6 m towards the stope (9.1) to be mined. The ore pass (11) penetrates the stope (9.1) to be mined to the contact surface (18) between the ore body and the hanging wall surrounding rock; the net roadway section size of the ore pass (11) is: width 2.2 - 3.0 m, height 2.4 - 3.0 m; 1.3) Along the crosscut haulage roadway (17), a pillar ore pass (10) is driven vertically or obliquely towards the pillar (8.1) to be mined. The pillar ore pass (10) penetrates the pillar (8.1) to be mined to the contact surface (18) between the ore body and the hanging wall surrounding rock; the net roadway section size of the pillar ore pass (10) is: width 2.2 - 3.0 m, height 2.4 - 3.0 m; 1.4) In the footwall surrounding rock (16) of the ore body within a range of 5 - 8 m below the pillar (8.1) to be mined, an off - vein pedestrian ventilation raise (6) is constructed upwards along the roof of the pillar ore pass (10). The size of the off - vein pedestrian ventilation raise (6) is: length 1.8 - 2.0 m, width 1.8 - 2.0 m; the slope of the off - vein pedestrian ventilation raise (6) is the same as the dip angle of the ore body; the top of the off - vein pedestrian ventilation and filling raise (6) is connected to the corresponding upper - level pillar ore pass (3), the lower end of the off - vein pedestrian ventilation and filling raise (6) is connected to the top of the pillar ore pass (10) at this level, and the right end of the upper - level pillar ore pass (3) is connected to the upper - level crosscut haulage roadway (2); 1.5) Along the vertical direction of the off - vein pedestrian ventilation raise (6), a pillar connection drift (5) perpendicular to the pillar (8.1) to be mined is constructed every 3 - 5 m, and a stope connection drift (7) connecting the stopes (9.1) on both sides of the pillar (8.1) is constructed on both sides of the off - vein pedestrian ventilation raise (6) until the ore body is just exposed and then stopped without penetrating into the ore body; the pillar connection drift (5) and the stope connection drift (7) are arranged alternately, and the vertical distance between them is ≥1.5 m; the section size of the pillar connection drift (5) is: width 1.8 - 2.0 m, height 2.0 - 2.2 m, length 5 - 8 m; the section size of the stope connection drift (7) is: width 1.8 - 2.0 m, height 2.0 - 2.2 m, length 5 - 8 m; S2 Pillar extraction and filling 2.1) Using a part of the intermediate pillar ore-drawing roadway (10) that penetrates into the ore body to be mined (8.1) as the free face, blast holes (12) parallel to the dip angle of the ore body are constructed upward; the blast holes (12) are arranged in a fan shape, with a hole depth of 1.8 - 2.2 m and a hole spacing of 0.6 - 0.8 m. Emulsion explosives are loaded into the blast holes (12), and non-electric detonator initiating networks are used for initiation. Millisecond blasting is adopted, and the delay error is ≤ 25 ms; 2.2) After blasting, a remote-controlled electric LHD is used to transport the stored ore (14) in the intermediate pillar stope along the intermediate pillar ore-drawing roadway (10). When the upper storage elevation of the stored ore (14) in the intermediate pillar stope is lowered to the same level as the bottom elevation of the first intermediate pillar connection drift (5) of the intermediate pillar (8.2) being mined, the ore drawing by the LHD stops. At this time, a stope mining space (13) is formed between the stored ore (14) in the intermediate pillar stope and the intermediate pillar (8.2) being mined. This stope mining space (13) serves as the working free face during the blasting of the next mining level, and the stored ore (14) in the intermediate pillar stope serves as the working platform for the next mining level; 2.3) From the intermediate pillar ore-drawing roadway (10) → the cross-cut ventilation raise outside the vein (6) → the intermediate pillar connection drift (5) → the stope mining space (13), the intermediate pillar (8.2) being mined is mined layer by layer upward; after each layer of blasting, a forced local ventilator is used for exhaust ventilation and discharged to the surface; 2.4) Repeat the above steps 2.2) - 2.3) until the intermediate pillar (8.2) being mined reaches the level of the crown pillar (4); after the mining is completed, a remote-controlled LHD is used for centralized ore drawing at the intermediate pillar ore-drawing roadway (10) at the bottom of the intermediate pillar (8.2) being mined; 2.5) After the ore drawing of the intermediate pillar (8.2) being mined is completed, high-density polyethylene pipes are laid from the upper-level haulage roadway (2) → the upper-level intermediate pillar ore-drawing roadway (3) → the cross-cut ventilation raise outside the vein (6) → the intermediate pillar connection drift (5). When backfilling the intermediate pillar stope (8.3) being backfilled, it is backfilled layer by layer from bottom to top; a backfill retaining wall (15) is constructed before each filling height reaches the intermediate pillar connection drift (5); when filling to the top, pressure grouting is carried out to ensure that the roof contact rate is ≥ 95%, forming a backfilled intermediate pillar stope (8.4); S3 Mining of the ore room 3.1) After the stoping and backfilling of all the stopes to be mined (8.1) and the stopes being mined (8.2) in the middle section are completed, or when there are more than two stopes to be mined (9.1) preceded by stopes (8.4) that have been backfilled, then the stopes to be mined (9.1) are mined; when mining the stopes to be mined (9.1), taking the part of the space in the stope to be mined (9.1) entered through the ore-drawing roadway (11) as the free face, a cut roadway (22) is constructed along the length direction of the stope to be mined (9.1). The cut roadway (22) is blasted using a wedge cut. The dip angle of the cut holes is 55° - 65°, the spacing of the auxiliary holes is ≤ 0.8 m, the spacing of the perimeter holes is ≤ 0.5 m respectively, the charging coefficient of the perimeter holes is ≤ 0.6, and the reserved smooth blasting layer thickness is ≥ 200 mm; blasting and stoping are carried out using the formed cut roadway (22) as the blasting and stoping space; emulsion explosive and non-electric detonating tubes are used for initiation, and blasting is carried out once for each completed bench working face; 3.2) After blasting is completed, partial ore drawing is carried out for the ore stored in the stope (20); a remote-controlled electric LHD is used to load and haul the ore stored in the stope (20) along the ore-drawing roadway (11) of the stope. When the upper stacking elevation of the ore stored in the stope (20) is lowered to a distance of 1.8 - 2.0 m from the stope (9.2) being mined corresponding to it in the vertical direction, the ore drawing and hauling are stopped; at this time, a stope stoping space (19) with a height of 1.8 - 2.0 m is formed between the ore stored in the stope (20) and the stope (9.2) being mined, and the stope stoping space (19) serves as the working free face for the blasting of the next bench of the stope (9.2) being mined; the remaining ore stored in the stope (20) serves as the next drilling working platform; 3.3) Before the workers enter the stope stoping space (19) for construction, mechanical ventilation is required for the stope (9.2) being mined; an exhaust-type local ventilator is installed in the stope connection roadway (7) on the other side of the stope (9.2) being mined. Fresh air flows from the off-vein pedestrian ventilation raise (6) through the stope connection roadway (7) into the stope stoping space (19). After flushing the working face, the polluted air is discharged to the surface through the stope connection roadway (7) on the other side of the ore body and the off-vein pedestrian ventilation raise (6) into the upper-section haulage roadway (2); 3.4) To facilitate the drilling and blasting operations of the workers on the ore stored in the stope (20), the surface of the remaining ore stored in the stope (20) should be leveled after partial ore drawing; during the leveling operation, the ore and rock that have become loose but not fallen on the roof and two sides should be pried down to ensure the safety of subsequent operations; the large pieces that fall during ore caving and roof prying should be broken during the leveling operation to facilitate ore drawing; 3.5) Repeat the above steps 3.1) - 3.2) until all the remaining ore stored in the stope (20) is discharged at one time when the stope (9.2) being mined reaches the top pillar (4); the ore is transported from the ore-drawing roadway (11) of the stope to the middle-section haulage roadway (17), loaded, and transported to the surface; after the final ore drawing is completed, the stope should be completely sealed in a timely manner.

2. A new non-pillar shrinkage stoping method with intermediate pillar recovery as claimed in claim 1, characterized in that: The ore-drawing roadway (11) of the ore chamber is located below the reserved ore (20) in the ore chamber, and the right end of the ore-drawing roadway (11) of the ore chamber is connected to the crosscut haulage roadway (17).

3. A new non-pillar shrinkage stoping method with intermediate pillar recovery as claimed in claim 1, characterized in that: The stull (8.2) being mined is connected to the off-vein pedestrian ventilation and filling raise (6) arranged in the footwall surrounding rock (16) of the ore body through the stull access drift (5).

4. A new non-pillar shrinkage stoping mining method with intermediate pillar recovery as claimed in claim 1, characterized in that: In step 2.3), the fresh air current passes through the forced local ventilator, and through the pipeline from the crosscut haulage roadway (17) → the stull ore-drawing roadway (10) → the off-vein pedestrian ventilation raise (6) → the stull access drift (5) → the stope mining space (13) of the stull. The polluted air is forced out and then flows from the stull access drift (5) → the off-vein pedestrian ventilation raise (6) → the stull ore-drawing roadway (3) of the upper crosscut → the upper crosscut haulage roadway (2) → the surface.

5. A new non-pillar shrinkage stoping method with intermediate pillar recovery as claimed in claim 1, characterized in that: The filled stope (8.4) is closed with a filling bulkhead (15) from the stull ore-drawing roadway (10) and the stull access drift (5).

6. A new non-pillar shrinkage stoping method with intermediate pillar recovery as described in claim 1, characterized in that: In step 3.1), when the width of the ore chamber to be mined (9.1) is less than 3 m, the width of the cut roadway (22) is the width of the ore chamber to be mined (9.1); when the width of the ore chamber to be mined (9.1) exceeds 3 m, the width of the cut roadway (22) is 2 - 3 m; the height of the cut roadway (22) is 2 - 4 m, and the length is the length of the ore chamber to be mined (9.1).

7. A new non-pillar shrinkage stoping method with intermediate pillar recovery as claimed in claim 1, characterized in that: In step 3.2), when partially drawing the reserved ore (20) in the ore chamber, the amount of ore drawn each time is 30% - 35% of the blasted amount, and the remaining reserved ore (20) in the ore chamber serves as the next drilling platform.

8. A new non-pillar shrinkage stoping method with intermediate pillar recovery as claimed in claim 1, characterized in that: In step 3.3), after the concentration of harmful substances in the ore chamber (9.2) being mined reaches the allowable value, the workers can enter the stope mining space (19) for construction.

9. A new non-pillar shrinkage stoping method with intermediate pillar recovery as claimed in claim 1, 2, 3, 4, 5, 6 or 7, characterized in that: The interval between the upper crosscut haulage roadways (2) is 5 - 6 m, and the construction is carried out vertically or obliquely at an angle of 45 - 60°, and the construction stops when it penetrates the contact surface (18) between the upper crosscut mined-out ore chamber (9.3) and the just-exposed ore body in the footwall surrounding rock.

10. A new non-pillar shrinkage stoping method with intermediate pillar recovery as claimed in claim 9, characterized in that: The ore body is mined from top to bottom, divided into several crosscuts with a crosscut height of 30 - 60 m. In each crosscut, the ore chamber to be mined (9.1) and the stull to be mined (8.1) are arranged along the strike of the ore body; the width of the ore chamber to be mined (9.1) is the same as the thickness of the ore body, the length of the ore block is 40 - 60 m, and the height is 30 - 60 m; the length of the crown pillar (4) is 40 - 60 m, the height is 4 - 8 m, and its width is the same as the thickness of the ore body; the width of the stull to be mined (8.1) is 6 - 10 m, the height is 30 - 60 m, and its width is the same as the thickness of the ore body.

11. A new non-pillar shrinkage stoping method with intermediate pillar recovery as described in claim 2, characterized in that: The ore body is mined from top to bottom, divided into several levels with a level height of 30 - 60m. In each level, the ore rooms to be mined (9.1) and the intermediate pillars to be mined (8.1) are arranged along the strike of the ore body; the width of the ore room to be mined (9.1) is the same as the thickness of the ore body, the length of the ore block is 40 - 60m, and the height is 30 - 60m; the length of the top pillar (4) is 40 - 60m, the height is 4 - 8m, and its width is the same as the thickness of the ore body; the width of the intermediate pillar to be mined (8.1) is 6 - 10m, the height is 30 - 60m, and its width is the same as the thickness of the ore body; the intermediate pillar being mined (8.2) is connected to the off-vein pedestrian ventilation and filling raise (6) arranged in the footwall surrounding rock (16) of the ore body through the intermediate pillar access drift (5), and the mined-out intermediate pillar stope (8.4) is closed with a filling dam (15) to the intermediate pillar ore-drawing roadway (10) and the intermediate pillar access drift (5); in step 2.3), the fresh air current passes through a forced local ventilator, through the pipeline from the level haulage roadway (17) → the intermediate pillar ore-drawing roadway (10) → the off-vein pedestrian ventilation raise (6) → the intermediate pillar access drift (5) → the stope mining space (13) of the intermediate pillar, and the polluted air is forced out and then from the intermediate pillar access drift (5) → the off-vein pedestrian ventilation raise (6) → the intermediate pillar ore-drawing roadway of the upper level (3) → the upper level haulage roadway (2) → the surface; in step 3.1), when the width of the ore room to be mined (9.1) is less than 3m, the width of the cut drift (22) is the same as the width of the ore room to be mined (9.1); when the width of the ore room to be mined (9.1) exceeds 3m, the width of the cut drift (22) is 2 - 3m; the height of the cut drift (22) is 2 - 4m, and the length is the same as the length of the ore room to be mined (9.1); in step 3.2), when partially drawing the ore stored in the ore room (20), the amount of ore drawn each time is 30% - 35% of the blasted amount, and the remaining ore stored in the ore room (20) serves as the next drilling working platform; in step 3.3), after the concentration of harmful substances in the ore room being mined (9.2) reaches the allowable value, the staff can enter the mining space (19) of the ore room for construction; the interval between the upper level haulage roadways (2) is 5 - 6m, and construction is carried out in a vertical or obliquely intersecting direction at 45 - 60°, and construction stops when it penetrates the contact surface (18) between the mined-out ore room (9.3) of the upper level and the newly exposed ore body in the upper wall surrounding rock.

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