Interval filling goaf stoping stud method for steeply inclined ore body

Abstract

The invention discloses an interval filling goaf stoping stud method for a steeply inclined ore body, and relates to the technical field of underground mining. The stud stoping method comprises the steps that the number of interval goaf areas is obtained, and a goaf area to be filled is obtained according to the number of the interval goaf areas; sealing columns on the two sides of the goaf to be filled; filling the to-be-filled goaf, and caving the studs in the unfilled goaf; and the caved intermediate columns are transported out through an ore removal structure of a recovery chamber located between the filling goaf. By means of interval filling and step-by-step recycling of the studs, the stoping efficiency and safety of the studs are improved, the loss and depletion of stoping of the studs are reduced, the mining preparation work amount is reduced, and the goaf can be effectively treated, and the purpose of safe stoping is achieved.

Description

Technical Field

[0001] This invention relates to the field of underground mining technology, and in particular to a method for intermittent filling of goaf and backfilling of pillars in steeply inclined ore bodies. Background Technology

[0002] In the history of mining steeply dipping, medium-thick ore bodies, the open-cut method is a commonly used mining method. During the mining process, each section is divided into stops and pillars. After the stops are mined out, pillars are left to support the stability of the goaf. The retention of pillars has led to the waste of mineral resources, and the lack of treatment of the goaf has also left huge safety hazards.

[0003] Current technologies for recovering residual pillars and managing goaf areas present several challenges. Directly recovering the pillars (interstitial pillars) from the collapsed goaf can cause safety issues such as goaf collapse and surface subsidence. If the goaf is completely filled before pillar recovery, the project is large-scale, the mining efficiency is low, and it can also cause significant dilution problems. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0005] In view of this, the present invention provides a method for intermittent filling of goaf in steeply inclined ore bodies to recover intermittent pillars. By intermittently filling and gradually recovering the intermittent pillars, the efficiency and safety of intermittent pillar recovery are improved, the loss and dilution of intermittent pillars are reduced, the amount of preparation work is reduced, and the effective treatment of goaf areas can be achieved, so as to achieve the goal of safe recovery.

[0006] Specifically, the following technical solutions are included: This invention provides a method for intermittent filling of goaf in steeply dipping ore bodies and the method for intermittent pillar mining includes: Obtain the number of interval goaf areas, and based on the number of interval goaf areas, obtain the goaf areas to be filled; The columns on both sides of the goaf to be filled are sealed. Fill the goaf to be filled, and the interstitial columns in the unfilled goaf collapse; The collapsed interstitial columns are transported out through the ore extraction structure of the recovery chamber located between the filled goaf areas.

[0007] Optionally, the method for inter-column mining further includes: Fill the recycling chamber; Based on the number of interval goaf areas, the next goaf area to be filled is obtained; Repeat the steps of sealing the columns on both sides of the goaf to be filled until all the intermediate columns are recovered and the recovered ore chamber is filled.

[0008] Optionally, the mine containing the steeply dipping ore body includes the inter-pillar, and top and bottom pillars located on both sides of the inter-pillar. The inter-pillar includes a ventilation shaft, a connecting passage, and the ore extraction structure left over from mining. The ventilation shaft is located between the top and bottom pillars and penetrates the inter-pillar. The connecting passage is located in the middle section of the inter-pillar and connects the ventilation shaft to the goaf on both sides. The ore extraction structure is located at the bottom of the recovery stope and is located on the same side as the bottom pillar.

[0009] Optionally, obtaining the number of interval goaf areas includes: The number N of interval goaf areas is obtained based on the Mathews stability chart method and the actual mining site structure parameters.

[0010] Optionally, obtaining the number N of interval goaf areas includes: Obtain the Mathews stability coefficient N', N'=Q'×A×B×C, where Q' is the correction value of Q, A is the rock stress coefficient, B is the joint orientation adjustment coefficient, C is the orientation adjustment coefficient of the exposed surface of the goaf, and Q is the rock mass quality grade and Q' is the rock mass quality index. Based on the unsupported Mathews stability chart, the hydraulic radius R value is obtained through N'; The theoretical maximum length of the goaf is obtained from the formula of hydraulic radius of rectangular mining area: R=(a×b) / [2(a+b)], where a is the vertical span, i.e. the width of the goaf, which is the actual width of the goaf in the mine; b is the span along the strike, which is the theoretical maximum length calculated by this formula. The number of inter-valved goaf areas, N, is obtained based on the theoretical maximum length, the actual goaf length, and the inter-column width, where N ≤ (b-l2) / (l1+l2), and l1 is the actual goaf length, which is a known value; l2 is the actual inter-column width, which is a known value; N is then rounded down to the nearest integer.

[0011] Optionally, Q represents the rock mass quality classification, Q' represents the rock mass quality index, and Q is the corrected rock mass quality classification. Q' is obtained when both the joint surface alteration degree coefficient and the in-situ stress influence factor coefficient in the Q value are 1: Q' = (RQD / J α )×(J r / J n In the formula, RQD is the rock quality index, J n J is the number of joint groups. r J is the joint roughness coefficient. α is the joint alteration coefficient.

[0012] Optionally, the sealing treatment of the columns on both sides of the goaf to be filled includes: Soil was filled into the pedestrian ventilation shaft formed by the intercolumns; The soil in question is the surface soil of the mining area.

[0013] Optionally, filling the goaf to be filled includes: The ore-producing structure was sealed off with a brick wall; The bottom layer of the goaf to be filled on both sides of the goaf is filled to a height of 8m to 10m. The upper layer of the goaf to be filled is then filled.

[0014] Optionally, the filler material used to fill the goaf is a mixture of ash and sand and water, wherein the mass ratio of ash and sand is more than 72%, and when filling the bottom layer, the mass ratio of ash and sand is 1:4 to 1:6, and the bottom layer filling strength is greater than 5 MPa; when filling the upper layer, the mass ratio of ash and sand is 1:15, and the upper layer filling strength is greater than 2 MPa.

[0015] Optionally, the interstitial pillars within the unfilled goaf area due to collapse include: Top excavation tunnels and bottom excavation tunnels are provided on both sides of the column; Based on the top and bottom tunneling boreholes, blast holes are arranged within the inter-column to cause it to collapse.

[0016] This invention provides a method for mining interstitial pillars in steeply inclined ore bodies by intermittent filling of goaf areas. The method includes: first, determining the number of interstitial goaf areas; second, filling the goaf areas on both sides of the interstitial goaf areas to form a recovery stope; third, sealing the interstitial pillars before filling them to prevent filler material from entering the recovery stope and affecting subsequent pillar extraction; fourth, filling the goaf areas on both sides of the interstitial goaf areas; fifth, arranging blast holes for the interstitial pillars within the goaf areas; sixth, caving the middle section of the interstitial pillars; and finally, transporting them out through the bottom structure of the recovery stope, thus achieving pillar recovery. This method improves pillar recovery efficiency and safety, reduces losses and dilution during pillar recovery, reduces preparatory work, and also enables goaf management, preventing collapses and surface subsidence, thereby enhancing safety in the goaf area.

[0017] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a flowchart illustrating the steps of a method for backfilling columns according to an embodiment of the present invention; Figure 2a This is a schematic diagram of the structure of a mining inter-pillar according to an embodiment of the present invention; Figure 2b According to Figure 2a The diagram shown is an AA-direction schematic diagram of the embodiment. Figure 3 This is a schematic diagram of an unsupported Mathews stability graph of the Mawdesley extended Mathews stability graph according to an embodiment of the present invention.

[0020] in, Figure 2a and Figure 2b The correspondence between the reference numerals and component names in the attached drawings is as follows: 1. Column, 2. Top column, 3. Bottom column, 4. Lower fill material, 5. Upper fill material, 6. Soil, 7. Ore extraction structure, 8. Recycling stope, 9. Top excavation borehole, 10. Bottom excavation borehole, 11. Pedestrian ventilation shaft, 12. Connecting passage, 13. Arrangement of blast holes. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Before providing a further detailed description of the embodiments of the present invention, the directional terms used in the embodiments of the present invention, such as "upper part", "lower part" and "side part", are not intended to limit the scope of protection of the present invention.

[0023] To make the technical solutions and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0024] Figure 1 This is a flowchart of the steps of a backfilling column method according to an embodiment of the present invention.

[0025] like Figure 1As shown, one embodiment of the present invention provides a method for intermittent filling of goaf in steeply inclined ore bodies, the method comprising: Step 1: Obtain the number of interval goafs, and based on the number of interval goafs, obtain the goafs to be filled. Step 2: Seal the columns on both sides of the goaf to be filled. Step 3: Fill the goaf to be filled and disintegrate the interstitial columns in the unfilled goaf. Step 4: The collapsed intercolumns are transported out through the ore extraction structure of the recovery chamber located between the filled goaf areas.

[0026] The method for mining inter-column blocks includes first determining the number of inter-goals, then filling the goafs on both sides of the inter-goals to form a recovery stope 8. Before filling the goafs on both sides of the inter-goals, the inter-column blocks 1 are sealed to prevent the filling material from entering the recovery stope 8 and affecting subsequent ore extraction from the inter-column blocks 1. After the inter-column blocks 1 are sealed, the goafs on both sides of the inter-goals to be filled are filled. Then, blast holes 13 are arranged for the inter-column blocks 1 within the inter-goals. The middle section of the inter-column blocks 1 is then caved and transported out through the bottom structure of the recovery stope 8, thus realizing the mining of the inter-column blocks 1. The method for mining inter-column blocks 1 of this application can improve the mining efficiency and safety of the inter-column blocks 1, reduce the loss and dilution during mining, reduce the amount of preparation work, and also achieve the treatment of goafs, preventing collapse and surface subsidence, and improving the safety of the goaf.

[0027] Specifically, losses refer to ore that cannot be extracted during mining, while dilution occurs when non-ore objects such as waste rock and backfill are mixed into the ore during mining, resulting in a reduction in the grade of the extracted ore. Related technologies involve filling the goaf before mining the pillars, requiring waiting for the backfill to harden and necessitating the excavation of new mining roadways and ore-drawing structures. Because the goaf already has backfill before mining the pillars, some ore within the original goaf cannot be extracted during mining, and backfill is mixed in during pillar extraction, causing losses and dilution. In this application, the pillars are mined first, followed by goaf filling, eliminating the need to wait for the backfill to harden or for the excavation of ore-drawing structures, thus improving mining efficiency. During mining, some residual ore in the original goaf can be blasted simultaneously, preventing the mixing of backfill and reducing losses and dilution. Preparation is a crucial preparatory stage in mining engineering, primarily involving dividing the ore blocks through excavated roadways to create conditions for subsequent drilling, ventilation, and transportation operations. Related technologies include tunneling of mining roadways and ore-discharge structures. This application, however, does not require the construction of new ore-discharge structures, and the amount of tunneling for mining roadways is reduced, thus reducing the amount of preparatory work.

[0028] In one feasible implementation, the inter-column mining method further includes: Step 5: Fill the recycling chamber; Step 1: Based on the number of interval goafs, obtain the next goaf to be filled; Repeat the steps of sealing the columns on both sides of the goaf to be filled until all intermediate columns are recovered and the goaf is filled.

[0029] In this process, after the interstitial pillars 1 within the recovery stope 8 collapse and are removed, the recovery stope 8 is filled in the same way as the goaf to be filled. The goaf is filled gradually from one side to the other, with interstitial pillars 1 being recovered within the recovery stope 8. After one set of interstitial pillars 1 within the recovery stope 8 is recovered and the recovery stope 8 is filled, the next set of goaf to be filled and interstitial pillars 1 are recovered. This process is repeated until all the interstitial pillars 1 in the middle section are recovered (excluding the outermost two interstitial pillars 1), and all goafs are filled. After the recovery stope 8 is filled, it is determined whether all goafs have been filled. If yes, the process ends; otherwise, the process continues with filling the remaining goafs after a certain number of intervals.

[0030] Understandably, "Reclaimed Mining Room 8" refers to the intermittently accessed goaf. If the number of intermittent goafs is 1, then the goafs are numbered from one side to the other: Goaf 1, Goaf 2... X. Goaf 1 and Goaf 3 are filled first, and Goaf 2 is designated as Reclaimed Mining Room 8. After Reclaimed Mining Room 8 is filled, Goaf 5 is filled, and Goaf 4 is designated as Reclaimed Mining Room 8. If the number of intermittent goafs is 2, then Goaf 1 and Goaf 4 are filled first, and Goaf 2 and Goaf 3 are designated as Reclaimed Mining Room 8. After Reclaimed Mining Room 8 is filled, Goaf 7 is filled, and Goaf 5 and Goaf 6 are designated as Reclaimed Mining Room 8, and so on.

[0031] Figure 2a This is a schematic diagram of the structure of a mining inter-pillar according to an embodiment of the present invention; Figure 2b According to Figure 2a The illustrated embodiment is shown in the AA direction schematic diagram.

[0032] It should be noted that, as Figure 2a and Figure 2b As shown, the mine containing the steeply inclined ore body includes a secondary pillar 1, and a top pillar 2 and a bottom pillar 3 located on both sides of the secondary pillar 1. The secondary pillar 1 includes a ventilation shaft 11, a connecting passage 12, and an ore extraction structure 7 left over from the mining process. The ventilation shaft 11 is located between the top pillar 2 and the bottom pillar 3 and passes through the secondary pillar 1. The connecting passage 12 is located in the middle section of the secondary pillar 1 and connects the ventilation shaft 11 with the goaf on both sides. The ore extraction structure 7 is located at the bottom of the recovery stope 8 and is located on the same side as the bottom pillar 3.

[0033] The aforementioned sections are all necessary passageways during mining. This application aims to mine the existing legacy pillar voids from bottom to top in a mid-level sequence, with multiple layers beneath the ore, such as... Figure 2a The diagram shows a single-layer ore pillar. Top pillar 2 and bottom pillar 3 also require recovery, but these are outside the scope of this application. This application primarily focuses on the recovery of interstitial pillar 1, which is handled by the attached... Figure 2a In the order from left to right, the inter-pillar 1 is gradually recovered and the goaf (including the goaf to be filled and the recovered stope 8) is gradually filled.

[0034] In one feasible implementation, obtaining the number of interval goaf zones includes: The number N of interval goaf areas is obtained based on the Mathews stability chart method and the actual mining site structure parameters.

[0035] It should be noted that the theoretical maximum goaf length is calculated using the Mathews stability chart method, and this length can guarantee the stability of the goaf.

[0036] Specifically, obtaining the number N of interval goaf areas includes: Obtain the Mathews stability coefficient N', N'=Q'×A×B×C, where Q' is the correction value of Q, A is the rock stress coefficient, B is the joint orientation adjustment coefficient, C is the orientation adjustment coefficient of the exposed surface of the goaf, and Q is the rock mass quality grade and Q' is the rock mass quality index. Based on the unsupported Mathews stability chart, the hydraulic radius R value is obtained through N'; The theoretical maximum length of the goaf is obtained from the formula of hydraulic radius of rectangular mining area: R=(a×b) / [2(a+b)], where a is the vertical span, i.e. the width of the goaf, which is the actual width of the goaf in the mine; b is the span along the strike, which is the theoretical maximum length calculated by the formula. The number of inter-mineral goafs, N, is obtained based on the theoretical maximum length, the actual goaf length, and the width of the inter-pillar. N ≤ (b-l2) / (l1+l2), where l1 is the actual goaf length (a known value) and l2 is the actual inter-pillar width (a known value). N is then rounded down to the nearest integer.

[0037] Where A is the rock stress coefficient, B is the joint orientation adjustment coefficient, and C is the orientation adjustment coefficient of the exposed surface of the goaf. A, B, and C are all obtained through Mathews stability charts.

[0038] It should be noted that Q' is obtained when both the joint surface alteration degree coefficient and the geostress influence factor coefficient in the Q value are 1: Q' = (RQD / J α )×(J r / J nIn the formula, RQD is the rock quality index, J n J is the number of joint groups. r J is the joint roughness coefficient. α Let Q be the joint alteration coefficient, Q be the rock mass quality grade, Q' be the rock mass quality index, and Q' be the modified rock mass quality grade. This formula is a conventional calculation formula in this field and will not be elaborated further.

[0039] Specifically, within the group of pillar voids left by the stope method, the number N of interleaved goafs is determined using the Mathews stability chart method and actual stope structure parameters from the mine. At the terminal level, preparations are first made to fill the first goaf ( Figure 2a The first goaf and the N+2 goaf are designated as the goaf to be filled. The N goafs in the middle form the recovery stope 8. First, the ventilation shaft 11 and connecting passage 12 in the intermediate column 1 are filled to prevent the filling slurry from flowing into the recovery stope 8 and blocking the bottom ore extraction structure 7 of the recovery stope 8, thus affecting the ore extraction of the intermediate column 1. Then, the first and N+2 goafs are filled. After the filling material solidifies and reaches the required strength, the N goafs in the middle of the first and N+2 goafs, i.e., the recovery stope 8, are used as the blasting free face to blast the intermediate column 1 in the intermediate recovery stope 8. The blasted intermediate column 1 is then transported out through the bottom roadway using the ore extraction structure 7 left at the bottom of the recovery stope 8. After the blasting of the interstitial pillar 1 in the middle part between the first and N+2 goafs, i.e., within the recovery stope 8, is completed, the recovery stope 8 is also filled, completing the first ore extraction from the interstitial pillar 1 and the filling of the goaf. Then, the 2N+3 goaf is filled, forming the recovery stope 8 between the N+2 goaf (already filled) and the 2N+3 goaf. The interstitial pillar 1 within this recovery stope 8 is blasted and collapsed, and the collapsed interstitial pillar 1 is transported out through the ore extraction structure 7 at the bottom of the recovery stope 8. Finally, the recovery stope 8 is filled. Then, 3N+4 goafs are filled, and after filling the recovery stope 8 between the 2N+3 and 3N+4 goafs, 4N+5 goafs are filled, and this process is repeated until all interstitial pillar 1s have collapsed and all goafs (goafs to be filled and recovery stopes 8) have been filled.

[0040] It should be noted that, in the direction of mining depth, the filling of goaf, the filling of inter-column 1 and the recovery of ore chamber 8 are carried out from bottom to top. In the horizontal direction (length), the filling steps of filling every N are repeated until the treatment of all goaf and the recovery of inter-column 1 are completed.

[0041] In one feasible implementation, sealing the columns on both sides of the goaf to be filled includes: Soil was filled into the pedestrian ventilation shafts formed by the intercolumnar columns; The soil in question is the surface soil of the mining area.

[0042] It should be noted that the interstitial column 1 contains a ventilation shaft 11 and a connecting passage 12 connecting the goaf areas. To prevent the slurry from the filler material from flowing into the recovery stope 8 through the interstitial column 1 during goaf filling, the ventilation shaft 11 and the connecting passage 12 need to be sealed before filling the goaf areas on both sides of the recovery stope 8. The main sealing is applied to the interstitial column 1 on the side of the goaf facing the recovery stope 8, which can be filled and compacted using existing surface soil from the mine. Since the natural angle of repose of the soil 6 is typically 30° to 40°, it solidifies together with the filler material from the goaf areas on both sides after contacting each other in the connecting passage 12. Therefore, while filling the ventilation shaft 11, the filler material from the goaf areas on both sides will not enter the recovery stope 8 through the connecting passage 12, achieving a good sealing effect.

[0043] For example, it can be observed from the recovery stope 8 whether there is any seepage of filling slurry. Specifically, when filling the goaf on both sides of the recovery stope 8, it can be observed from the bottom structure outlet of the recovery stope 8 whether there is any flow of filling slurry. It can be checked whether the filling slurry seeps into the recovery stope 8 from the ventilation shaft 11 of the inter-column 1 to confirm whether there is any slurry leakage during the filling of the goaf. If it is found that the filling slurry flows out from the ventilation shaft 11, the filling of the goaf should be stopped and subsequent treatment should be carried out. After the ventilation shaft 11 and the connecting passage 12 are completely closed again, the filling treatment of the goaf can be continued.

[0044] In one feasible implementation, filling the goaf to be filled includes: Bricklaying to seal off the ore-exit structure; The bottom layer of the goaf to be filled on both sides of the interval goaf is filled with a filling height of 8m to 10m; The upper layer of the goaf to be filled is then filled.

[0045] Among them, the ore-exiting structure 7 is a structure left over from the original mining, similar to a fence, with a pointed top that allows the collapsed interstitial columns 1 to be discharged from the outlet through the pointed slope, preventing them from accumulating in the recovery ore chamber 8. Since each goaf is equipped with an ore-exiting structure 7, before filling the goaf with filler slurry, the ore-exiting structure 7 is first sealed with cement to prevent the filler slurry from seeping out through the ore-exiting structure 7.

[0046] It should be noted that the slurry used to fill the goaf is a mixture of lime, sand and water, with lime and sand accounting for more than 72% of the mass. When filling the bottom layer, the lime-sand mass ratio is 1:4 to 1:6, and the bottom layer filling strength is greater than 5 MPa; when filling the upper layer, the lime-sand mass ratio is 1:15, and the upper layer filling strength is greater than 2 MPa.

[0047] For example, the ash in the lime-sand mixture can be cement or cementitious powder, while the sand is tailings, which is mineral waste that can be directly taken from the mine. Generally, after being mixed in proportion to form a filler slurry and solidified, the strength generally does not change much. Usually, the strength of the lower filler body 4 is greater than 5MPa, and the strength of the upper filler body 5 is greater than 2MPa. The upper filler body 5 also serves as the base plate for the recovery of the bottom pillar of the upper mining area in the depth direction, so its strength cannot be lower than 2MPa.

[0048] It is understandable that the filling of the goaf and the recovery stope 8 can be achieved by laying pipelines into the goaf or drilling holes on the surface to fill the goaf and the recovery stope 8 with filler slurry, which is existing technology and will not be elaborated here.

[0049] In one feasible implementation, the interstitial pillars within the collapsed and unfilled goaf include: Top excavation tunnels and bottom excavation tunnels are set on both sides of the column; Based on the top-excavated borehole roadway and the bottom-excavated borehole roadway, blast holes are arranged in the inter-pillar to cause the inter-pillar to collapse.

[0050] After the sealing of the inter-column 1 is completed and the goaf to be filled is filled, the inter-column 1 is sealed on both sides above and below, that is, on both sides of the bottom and top of the ventilation shaft 11. Figure 2a One tunnel is excavated in each of the left and right directions, namely the top excavation borehole 9 and the bottom excavation borehole 10. The lengths of the top excavation borehole 9 and the bottom excavation borehole 10 are equal to the thickness of the support column 1. Figure 2b The distances between the left and right sides are the same. The connecting passage 12 in the original pedestrian ventilation shaft 11 serves as the boundary. Above and below the connecting passage 12, blast holes are arranged 13 via the top excavation borehole roadway 9 and the bottom excavation borehole roadway 10, respectively. Figure 2b As shown, multiple blast holes are arranged in a fan shape to improve the reliability of the collapse of the inter-pillar 1. After the inter-pillar 1 collapses, it forms fragments, which fall into the roadway below through the ore extraction structure 7 at the bottom of the recovery room 8. The ore is then transported out by mine cars to realize the recovery of the inter-pillar 1.

[0051] Example Taking a mining area in a certain mine as an example, there are several goaf areas in a certain section of the mine, such as... Figure 2a The diagram shows the goaf areas along the strike line, numbered from left to right as 1, 2, 3, 4, 5, ... The goaf area spans approximately 30m along the strike line and 52m perpendicular to the strike line (perpendicular to the strike line refers to...). Figure 2a (In the direction of the middle and outside), the thickness of the intercolumnar column is 2m, that is... Figure 2b The distance between the left and right sides.

[0052] The number of interval goafs N is determined using the Mathews stability chart method. The Mathews stability coefficient N' represents the rock mass's ability to maintain stability under given stress conditions, and its calculation formula is as follows: N'=Q'×A×B×C(1) In the formula, Q' is the corrected value of Q, A is the rock stress coefficient, B is the joint orientation adjustment coefficient, C is the orientation adjustment coefficient of the exposed surface in the goaf, Q is the rock mass quality grade, Q' is the rock mass quality index, and Q is the corrected rock mass quality grade. Q' is obtained when both the joint surface alteration degree coefficient and the geostress influence factor coefficient in the Q value are 1, as shown in the following formula: Q' = (RQD / J) α )×(J r / J n (2) In the formula, RQD is the rock quality index, J n J is the number of joint groups. r J is the joint roughness coefficient. α Let be the joint alteration coefficient. Formula (2) is a conventional formula in this field and will not be elaborated further.

[0053] Among them, the rock stress coefficient A is mainly related to the uniaxial compressive strength σ of intact rock. c It is related to the ratio of the horizontal induced stress σ1 parallel to the exposed surface, when σ c When / σ1≤2, A=0.1; when 2<σ c When / σ1<10, A=0.1125(σ c / σ1)-0.125; when σ c When σ1 ≥ 10, A = 1. c The values ​​σ1 and σ2 can be obtained through experimentation and calculation, which are existing methods for obtaining them.

[0054] The joint orientation adjustment coefficient B depends on the angle between the direction of the main joint group and the working face of the stope. It is obtained by the Mathews stability chart method and by the chart of the angle α between the stope wall and the joint and the joint orientation adjustment coefficient B. According to this embodiment, B = 0.8 is obtained by the angle between the stope wall and the joint.

[0055] The orientation adjustment coefficient C of the exposed surface in the goaf can be estimated using an empirical formula (C=8-6cosα). The maximum value of the gravity adjustment coefficient is 8 for the two sides of the stope, and the minimum value of 2 is taken for the roof of the horizontal stope. Here, it is obtained using the Mathews stability chart method. Based on the stope dip angle and the orientation adjustment coefficient C (gravity adjustment factor C) of the exposed surface in the stope, C=5.4 is obtained according to the stope dip angle in this embodiment.

[0056] Based on the rock mechanics data of the mine, and using the Mathews stability chart method, the parameters are Q'=8.73, A=0.95, B=0.80, C=5.4, then N'=35.84.

[0057] Based on the correspondence between the stability coefficient N' and the hydraulic radius R of the exposed stope in the unsupported Mathews stability chart of the Mawdesley extended Mathews stability chart, as shown in the appendix. Figure 3 As shown, in the unsupported transition zone, when N'=35.84, a vertical line is drawn upwards and intersects with the second curve encountered. The ordinate of the intersection point is the hydraulic radius R=13.18m. The vertical span of this stope is approximately a=52m. According to the formula for calculating the hydraulic radius of a rectangular stope, R=(a×b) / [2(a+b), the maximum span along the strike is b=55.63m. In this example, the length of the mine along the strike is approximately l1=30m, and the thickness of the inter-pillar is l2=8m. The number of fixed-interval goaf areas N≤(b-l2) / (l1+l2)=(55.63-8) / (30+8)=1.25. Therefore, N is taken as 1, that is, the existing goaf areas are filled by taking the number of one-to-one intervals. In other words, according to the formula for calculating the hydraulic radius of a rectangular stope: R=(a×b) / [2(a+b)], where a is the vertical span, i.e., the width of the goaf, which is the actual width of the goaf in the mine; b is the span along the strike, which is the theoretical maximum length calculated by this formula. N≤(b-l2) / (l1+l2). In the formula, l1 is the actual length of the goaf in the mine, l2 is the actual width of the inter-pillar, and N is rounded down to the nearest integer.

[0058] Figure 2a From left to right, the goaf areas are designated as Goaf 1, Goaf 2, Goaf 3, Goaf 4, and Goaf 5. Based on the above calculations, the interstitial pillars between Goaf 1 and Goaf 3 are first sealed. After sealing, Goaf 1 and Goaf 3 are simultaneously filled with filler material, ensuring that the strength of the lower filler material near the bottom pillar reaches at least 5 MPa, with a height of 8 to 10 meters. The strength of the upper filler material near the top pillar needs to reach at least 2 MPa. Before filling the goaf areas on both sides of the recovery stope, the bottom ore extraction structure also needs to be sealed with cement walls. Then, explosives are placed in the blast holes to cause the interstitial pillars in the recovery stope to collapse, and the ore is transported out through the bottom ore extraction structure. Finally, after sealing the ore extraction structure with cement walls, the recovery stope is filled with filler material, with the strength requirements of the filler material in the goaf area being consistent.

[0059] Understandably, one approach is to first seal all the interstitial pillars that need to be sealed, and then gradually fill the goaf with filler material. Alternatively, the interstitial pillars can be filled gradually, meaning that the interstitial pillars on both sides of the goaf to be filled can be sealed first, and after the interstitial pillars have been mined out and the reclaimed ore chamber has been filled, the interstitial pillars on both sides of the next goaf to be filled can be sealed. If N=2, then the second and third goafs are used as reclaimed ore chambers, which contain three interstitial pillars. The middle structure does not need to be sealed; blast holes can be directly arranged.

[0060] Continue filling the fifth goaf with filler material. The fourth goaf, located between the third and fifth goafs, is used as a recovery stop. Then repeat the above steps, mining the pillars in the fourth goaf and filling it. Then fill the seventh goaf, and so on, until all the pillars in the middle of the goaf are recovered and the goaf is completely filled.

[0061] In this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The term "a plurality" refers to two or more unless otherwise expressly defined.

[0062] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. The invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only.

[0063] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for intermittent filling of goaf and extraction of pillars in a steeply dipping ore body, characterized in that, The method of inter-column mining includes: Obtain the number of interval goaf areas, and based on the number of interval goaf areas, obtain the goaf areas to be filled; The columns on both sides of the goaf to be filled are sealed. Fill the goaf to be filled, and the interstitial columns in the unfilled goaf collapse; The collapsed interstitial columns are transported out through the ore extraction structure of the recovery chamber located between the filled goaf areas.

2. The method for intermittent filling of goaf and extraction of pillars in steeply dipping ore bodies according to claim 1, characterized in that, The method of inter-column mining also includes: Fill the recycling chamber; Based on the number of interval goaf areas, the next goaf area to be filled is obtained; Repeat the steps of sealing the columns on both sides of the goaf to be filled until all the intermediate columns are recovered and the recovered ore chamber is filled.

3. The method for intermittent filling of goaf and pillar mining in steeply dipping ore bodies according to claim 2, characterized in that, The mine containing the steeply dipping ore body includes the aforementioned inter-pillar, and top and bottom pillars located on both sides of the inter-pillar. The inter-pillar includes a ventilation shaft, a connecting passage, and the ore extraction structure left over from mining. The ventilation shaft is located between the top and bottom pillars and penetrates the inter-pillar. The connecting passage is located in the middle section of the inter-pillar and connects the ventilation shaft to the goaf on both sides. The ore extraction structure is located at the bottom of the recovery stope and is located on the same side as the bottom pillar.

4. The method for intermittent filling of goaf and extraction of pillars in steeply dipping ore bodies according to claim 3, characterized in that, The number of interval goaf areas obtained includes: The number N of interval goaf areas is obtained based on the Mathews stability chart method and the actual mining site structure parameters.

5. The method for intermittent filling of goaf and extraction of pillars in steeply dipping ore bodies according to claim 4, characterized in that, The number N of interval goaf areas obtained includes: Obtain the Mathews stability coefficient N', N'=Q'×A×B×C, where Q' is the correction value of Q, A is the rock stress coefficient, B is the joint orientation adjustment coefficient, C is the orientation adjustment coefficient of the exposed surface of the goaf, and Q is the rock mass quality grade and Q' is the rock mass quality index. Based on the unsupported Mathews stability chart, the hydraulic radius R value is obtained through N'; The theoretical maximum length of the goaf is obtained from the formula of hydraulic radius of rectangular mining area: R=(a×b) / [2(a+b)], where a is the vertical span, i.e. the width of the goaf, which is the actual width of the goaf in the mine; b is the span along the strike, which is the theoretical maximum length calculated by the formula. The number of inter-valved goaf areas, N, is obtained based on the theoretical maximum length, the actual goaf length, and the inter-column width, where N ≤ (b-l2) / (l1+l2), and l1 is the actual goaf length, which is a known value; l2 is the actual inter-column width, which is a known value; N is then rounded down to the nearest integer.

6. The method for intermittent filling of goaf and extraction of pillars in steeply dipping ore bodies according to claim 5, characterized in that, Q represents the rock mass quality grade, Q' represents the rock mass quality index, and Q is the corrected rock mass quality grade. Q' is obtained when both the joint surface alteration degree coefficient and the in-situ stress influence factor coefficient in the Q value are 1: Q' = (RQD / J α )×(J r / J n In the formula, RQD is the rock quality index, J n J is the number of joint groups. r J is the joint roughness coefficient. α is the joint alteration coefficient.

7. The method for intermittent filling of goaf and pillar mining in steeply dipping ore bodies according to claim 3, characterized in that, The sealing treatment of the columns on both sides of the goaf to be filled includes: Soil was filled into the pedestrian ventilation shaft formed by the intercolumns; The soil in question is the surface soil of the mining area.

8. The method for intermittent filling of goaf and extraction of pillars in steeply dipping ore bodies according to claim 3, characterized in that, The filling of the goaf to be filled includes: The ore-producing structure was sealed off with a brick wall; The bottom layer of the goaf to be filled on both sides of the goaf is filled to a height of 8m to 10m. The upper layer of the goaf to be filled is then filled.

9. The method for intermittent filling of goaf and extraction of pillars in steeply dipping ore bodies according to claim 8, characterized in that, The filler material used to fill the goaf is a mixture of ash, sand and water, with the ash and sand accounting for more than 72% by mass. When filling the bottom layer, the ash and sand mass ratio is 1:4 to 1:6, and the bottom layer filling strength is greater than 5 MPa. When filling the upper layer, the ash and sand mass ratio is 1:15, and the upper layer filling strength is greater than 2 MPa.

10. The method for intermittent filling of goaf and extraction of pillars in steeply dipping ore bodies according to claim 1, characterized in that, The interstitial columns within the unfilled goaf area include: Top excavation tunnels and bottom excavation tunnels are provided on both sides of the column; Based on the top and bottom tunneling boreholes, blast holes are arranged within the inter-column to cause it to collapse.

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