Combined mining method of induced caving of hanging roof pillars and sublevel caving with vertical deep-hole ore drawing and undercut

Abstract

A combined mining method of induced caving of suspended roof pillars and sublevel caving with bottom pillars by vertical deep-hole ore drawing, comprising the following steps: (1) Divide the steeply inclined ore body into levels, sublevels, suspended roof pillars and bottom pillars; (2) The level haulage roadway, the drilling roadway and the bottom pillar are respectively arranged outside and inside the ore body along the strike of the ore body; (3) The upper sublevel is mined in advance of the lower sublevel in sequence; (4) As the working face advances, when the length of the top pillar and the exposed area of the hanging wall rock reach the critical caving value, the suspended roof pillar is gradually induced to cave and recovered from the first mining part of the stope, and the overlying waste rock falls into the goaf to fill part of the stope to play a role in controlling ground pressure; continuous retreating mining is carried out in this order; (5) The mined ore and the ore of the recovered suspended roof pillar are intensively transported to the level ore pass through the funnels and the ore-drawing roadway, and then transported to the surface by the mine transportation and hoisting system. Compared with the sublevel caving method with bottom pillars, the present invention improves the ore recovery rate and reduces the ore dilution rate.

Description

Technical Field

[0001] The present invention relates to a mining method for underground mining of metal mines, specifically a combined mining method of induced caving of hanging roof pillars and vertical deep-hole ore drawing with sublevel caving for steeply inclined medium-thick ore bodies. Background Art

[0002] For low-value steeply inclined thin to medium-thick ore bodies with medium to high stability of surrounding rock and ore, which account for a large proportion of China's mineral resources occurrence, open stoping methods such as shrinkage stoping and sublevel stoping with sublevel drilling are often used. Such open stoping methods are widely used in metal mines because of their simple technical form, high recovery rate, and low dilution and loss rates. However, with the increase of mining depth, the in-situ stress increases, the fragmentation degree of ore and rock intensifies, the ore dilution rate increases, and stope accidents occur frequently, which has now become a common problem in the industry. However, no answer is given in existing mining manuals and textbooks on how technology should be reformed.

[0003] The directions for the reform of open stoping methods mainly include improving to controlled roof open stoping methods or converting to filling methods and caving methods. Controlled roof open stoping methods mainly use bolts and cables to control the roof. Although they have certain effects in small areas, they have high support costs, large on-site workloads, high technical risks, and cannot fundamentally solve the applicability problems of mining methods for large-scale buried ore bodies. The filling method, although having certain technical advantages, is limited by the filling cost and is difficult to be popularized and used in low-value ore bodies. Generally, the caving method has relatively large dilution and loss rates, but it has great advantages in production cost, safety, and process continuity. Summary of the Invention

[0004] Guided by the concept of collaborative mining and giving full play to the respective advantages and characteristics of induced caving technology, sublevel stoping with sublevel drilling, and sublevel caving with bottom pillars, the present invention proposes a combined mining method of induced caving of hanging roof pillars and vertical deep-hole ore drawing with sublevel caving. It utilizes the advantages of low ore loss and dilution rates and high recovery rate of ore drawing in the open stope of sublevel stoping with sublevel drilling to set hanging roof pillars. Before the recovery of the hanging roof pillars, drilling, blasting, ore drawing, and ore removal are carried out in the open stope at each sublevel. As the sublevel stoping work progresses within the stage, the length of the hanging roof pillar and the exposed area of the hanging wall and footwall surrounding rock gradually increase, resulting in the hanging roof pillar and the hanging wall and footwall surrounding rock gradually reaching the critical instability state. At this time, the hanging roof pillar is recovered by sectional induced caving starting from the first mining area, reducing the exposed length of the hanging roof pillar and keeping its length within the safe range at all times. Due to the induced caving of the hanging roof pillar, the overlying waste rock falls into the open stope from the induced caving area, filling part of the mined-out area, and at the same time reducing the exposed area of the hanging wall and footwall surrounding rock.

[0005] In this way, while continuously advancing stoping, inducing caving to recover the hanging roof pillars and treating the mined-out area, the blasted ore is kept as much as possible for ore drawing in the open stope to reduce the ore loss and dilution rates, and at the same time solve the technical problems brought about by the increase of ore body burial depth as described above.

[0006] The technical solution adopted by the present invention is as follows: a combined mining method of induced caving of suspended roof pillars and vertical deep-hole caving with undercutting in sublevels, comprising the following steps:

[0007] (1) Divide the steeply inclined ore body into stages, sublevels, suspended roof pillars and undercutting pillars. For medium-thick and above-medium-thick ore bodies, the stope is arranged along the strike, and the length of the ore room is the same as the distance between adjacent ore passes;

[0008] (2) The stage haulage roadway, pedestrian ventilation shaft and ore pass are all arranged outside the mining displacement boundary of the ore body in the lower stage, and the distance from the ore body is not less than 10 m. The stope is connected to the stage haulage roadway through the stope access roadway, and the pedestrian ventilation shaft is connected to the sublevel drilling roadway through the sublevel stope access roadway. The ore-drawing roadway is arranged on the outer side of the footwall vein;

[0009] (3) The funnels are arranged parallel to the strike of the ore body in the sublevel drilling roadway, and are located at the bottom of the stope to create drawpoints. The funnels are arranged ahead of the stope. A cut is made at the first mining part of the sublevel drilling roadway, and then vertical upward fan-shaped medium-deep holes are drilled in the sublevel drilling roadway. During ore caving, 3 - 6 rows of blast holes are blasted each time, and retreating mining is carried out. In the stage, the upper sublevel is mined and blasted ahead of the lower sublevel;

[0010] (4) As the mining face advances, when the length of the top pillar and the exposed area of the hanging wall rock reach the critical caving value, the suspended roof pillar is gradually induced to cave and recovered from the first mining part of the stope. The caved ore of the suspended roof pillar falls into the open space and is discharged from the drawpoint together with the ore;

[0011] (5) The ore fallen in the stope and the ore of the induced-caved suspended roof pillar are transported to the ore pass by a load-haul-dump machine, and then transported to the surface through the mine's transportation and hoisting system.

[0012] The stage height described in step (1) is 55 - 65 m, the sublevel height is 10 - 18 m, the thickness of the suspended roof pillar is 6 - 10 m, the thickness of the undercutting pillar is 6 - 10 m, and the length of the ore block is the distance between adjacent ore passes, which is 50 - 80 m.

[0013] The specification of the stage haulage roadway described in step (2) is 3.5×3 m 2 , the specification of the pedestrian ventilation raise is 2×2 m 2 , the specification of the ore pass is 3×3 m 2 , the specification of the stope access roadway is 2.5×2.2 m 2 , the specification of the sublevel stope access roadway is 2.2×2.2 m 2 , the specification of the sublevel drilling roadway is 2.8×2.8 m 2 , the specification of the ore-drawing roadway is 2.5×2.5 m 2 .

[0014] The height of the funnel described in step (3) is 5 - 8 m, and the size of the funnel opening is 8×8 m 2 , and the size of the funnel neck is 2.2×2.2 m 2 , and the size of the funnel through is 2.2×2.2 m 2 , and the size of the cutting groove is 2×2×12 m 2 , the length of the vertical upward fan-shaped medium-deep hole is 5 - 20 m, the row spacing of the blast holes is 1.5 - 1.8 m, and the distance that the upper section leads the lower section is 3 - 5 m.

[0015] The specific operation steps for inducing caving to recover the hanging roof pillar described in step (4) are as follows:

[0016] From the upper-stage haulage roadway, a hanging roof pillar drilling roadway is driven downward every 10 m to induce caving to recover the hanging roof pillar. The end of the drilling roadway shall not be less than 5 m away from the hanging roof pillar. Hanging roof pillar recovery blast holes are drilled from the drilling roadway towards the hanging roof pillar to be recovered, charged in sections, and millisecond-delay blasting is used; the fallen hanging roof pillar is discharged through the funnel, and the overlying waste rock falls from the position of the recovered hanging roof pillar and fills part of the mined-out area.

[0017] The size of the hanging roof pillar drilling roadway is 2.2×2.2 m 2 , the length of the hanging roof pillar recovery blast holes is 10 - 20 m, and the millisecond-delay time is 20 - 80 ms.

[0018] The size of the load-haul-dump described in step (5) is 0.5 - 3 m 3 .

[0019] The prominent advantages of the present invention are as follows:

[0020] (1) A hanging roof pillar is set to form an open-stope ore-drawing condition, improving the ore recovery rate;

[0021] (2) With the retreating stoping, the length of the hanging roof pillar and the open-stope area will continuously increase. When the length of the remaining pillar and the exposed area of the hanging wall surrounding rock reach the critical caving value, the hanging roof pillar is gradually induced to cave and recovered from the first stoping part of the stope, improving the ore extraction rate;

[0022] (3) The overlying waste rock flows in from the position where the hanging roof pillar is induced to cave and fills part of the mined-out area. While recovering the hanging roof pillar, the exposed area of the mined-out area is reduced, and the ground pressure of the stope is better controlled;

[0023] (4) The loss rate is low. This mining method does not leave intermediate pillars, only leaves a hanging roof pillar, and gradually recovers the hanging roof pillar as the stoping progresses, recovering as much of the ore in the stope as possible to reduce the loss rate;

[0024] (5) The bottom pillar serves as a buffer layer for sectional drilling and blasting ore caving, and the ore-drawing roadway is connected to the funnel for centralized ore drawing, improving the ore-drawing efficiency;

[0025] (6) It has the advantages of the sublevel caving method with sill pillars. During the stoping process, operations such as drilling, blasting, ore drawing, and temporary support are all carried out in the roadway. Personnel and equipment do not enter the goaf or the stope, ensuring the safety of personnel construction. Description of the Drawings

[0026] Figure 1 It is a cross-sectional view of the combined mining method of induced caving of suspended roof pillars and sublevel caving with vertical deep holes and sill pillars according to the present invention, taken along line I-I.

[0027] Figure 2 It is a cross-sectional view of the combined mining method of induced caving of suspended roof pillars and sublevel caving with vertical deep holes and sill pillars according to the present invention, taken along line II-II.

[0028] Figure 3 It is a cross-sectional view of the combined mining method of induced caving of suspended roof pillars and sublevel caving with vertical deep holes and sill pillars according to the present invention, taken along line III-III.

[0029] Figure 4 It is a schematic diagram of the stope after the recovery of the suspended roof pillar in the combined mining method of induced caving of suspended roof pillars and sublevel caving with vertical deep holes and sill pillars according to the present invention.

[0030] The markings in the figure are: stope access drift 1, unmined ore 2, vertical fan medium-deep holes 3, peach-shaped ore pillar 4, caved ore 5, cut 6, suspended roof pillar drilling roadway 7, suspended roof pillar recovery blast holes 8, open stope 9, suspended roof pillar 10, waste rock in the upper stage 11, upper stage haulage roadway 12, ore pass 13, pedestrian ventilation shaft 14, sublevel stope access drift 15, stage haulage roadway 16, ore drawing roadway 17, sublevel drilling roadway 18. Detailed Embodiments

[0031] The technical solutions of the present invention will be further described below with reference to the drawings and examples.

[0032] As Figures 1 to 4 shown, the combined mining method of induced caving of suspended roof pillars and sublevel caving with vertical deep holes and sill pillars according to the present invention includes the following steps:

[0033] (1) Divide the stope elements of the combined mining method of induced caving of suspended roof pillars and sublevel caving with vertical deep holes and sill pillars. The stage height is 63 m, 4 sublevels are set, each sublevel height is 12 m, the thickness of the suspended roof pillar is 8 m, and the thickness of the sill pillar is 7 m; for medium-thick and medium-thick above ore bodies, the stope is arranged along the strike, the length of the ore room is 60 m, and the width of the ore room is 10 m.

[0034] (2) Drive a stage haulage roadway 16 with a cross-section of 3.5×3 m outside the mining displacement boundary from the lower stage ore body; the stage haulage roadway is 20 m away from the ore body; from the stage haulage roadway 16, drive a 2.2×2.2 m 2 every 60 m 2The stope access drift 1; It is driven 2.5×2.5m at 3.5m on one side of the lower orebody footwall 2 The ore-drawing drift 17; It is 10m away from the orebody and is driven 2×2m parallel to the orebody from the stope access drift 1 2 The pedestrian ventilation shaft 14, and a 2.2×2.2m drift is driven towards the orebody every 12m from the pedestrian ventilation shaft 14 2 The sublevel stope access drift 15; It is 14m away from the orebody and is driven 3×3m on the side wall of the stope access drift 2 The ore pass 13.

[0035] (3) The funnels are arranged parallel to the orebody strike of the sublevel drilling drift. Funnels are opened from the ore-drawing drift 17 into the orebody. The funnel height is 7m, the drawpoint is 2.2×2.2m 2 , the neck of the funnel is 2.2×2.2m 2 , the funnel mouth is 8×8m 2 ; After the sublevel stope access drift 15 reaches the orebody, a 2.8×2.8m 2 sublevel drilling drift 18 is driven parallel to the orebody. A row of vertical fan-shaped longholes 3 with a length of 5 - 20m is drilled into the orebody every 1.7m from the sublevel drilling drift 18. A 2×2×12m 3 cutting slot 6 is driven at the first mining part of the sublevel. The other three sublevel projects are the same; The upper sublevel is 5m ahead of the lower sublevel for blasting.

[0036] (4) Specific measures for the recovery of the hanging roof pillar. A 2.2×2.2m 2 hanging roof pillar induced caving drilling drift 7 is driven downward from the upper stage haulage drift 12. The end of this drilling drift 7 is more than or equal to 5m away from the hanging roof pillar. The spacing of the hanging roof pillar induced caving drilling drift 7 is 10m. Each time, the length of the hanging roof pillar recovered by induced caving is 10m; 10 - 20m hanging roof pillar recovery blast holes 8 are drilled from the end of the hanging roof pillar drilling drift 7 towards the hanging roof pillar. Millisecond differential blasting is used, and the millisecond differential time is 20 - 80ms; When the length of the hanging roof pillar and the exposed area of the hanging wall rock reach the critical caving value, the hanging roof pillar is gradually induced to cave and recovered from the first mining part of the stope.

[0037] (5) The ore 5 caved in the stope and the ore of the induced caving hanging roof pillar 10 are transported out by a load-haul-dump machine, transported to the ore pass 13, and then the ore is transported to the surface through the stage haulage drift 16.

Claims

1. A combined mining method of induced caving of suspended roof pillars and sublevel caving with vertical deep-hole ore drawing and undercut, characterized in that, It includes the following steps: (1) Divide the steeply inclined ore body into levels, sublevels, hanging pillars and sill pillars. For medium-thick and above medium-thick ore bodies, the stope is arranged along the strike, and the length of the ore room is the same as the distance between adjacent ore passes; The height of the level is 55 - 65m, the height of the sublevel is 10 - 18m, the thickness of the hanging pillar is 6 - 10m, the thickness of the sill pillar is 6 - 10m, and the length of the ore room is the distance between adjacent ore passes, which is 50 - 80m; (2) The level haulage roadway, pedestrian ventilation shaft and ore pass are all arranged outside the mining displacement boundary of the ore body in the lower level, and the distance from the ore body is not less than 10m. The stope is connected to the level haulage roadway through the stope access roadway. The pedestrian ventilation shaft and the sublevel drilling roadway are connected through the sublevel stope access roadway. The ore drawing roadway is arranged on the outer side of the footwall vein; The specifications of the stage haulage roadway are 3.5×3 m 2 , the specifications of the pedestrian ventilation shaft are 2×2 m 2 , the specifications of the ore pass are 3×3 m 2 , the specifications of the stope access drift are 2.5×2.2 m 2 , the sectional stope access drift is 2.2×2.2 m 2 , the sectional drilling roadway is 2.8×2.8 m 2 , the specifications of the ore drawing roadway are 2.5×2.5 m 2 ; (3) The funnels are arranged parallel to the strike of the ore body in the sublevel drilling roadway, located at the bottom of the stope to create drawpoints, and the funnels are arranged ahead of the stope. A cut is made at the first mining part of the sublevel drilling roadway. Then, vertical upward fan-shaped medium-deep holes are drilled in the sublevel drilling roadway. During ore drawing, 3 - 6 rows of blast holes are blasted each time, and retreating mining is carried out. In the level, the upper sublevel is mined and blasted ahead of the lower sublevel; The height of the funnel is 5 - 8 m, and the size of the funnel opening is 8×8 m 2 , and the size of the funnel neck is 2.2×2.2 m 2 , and the size of the funnel through is 2.2×2.2 m 2 , and the size of the cutting groove is 2×2×12 m 3 , the length of the vertical upward fan-shaped medium-deep hole is 5 - 20 m, the row spacing of the blast holes is 1.5 - 1.8 m, and the distance that the upper section leads the lower section is 3 - 5 m; (4) As the mining face advances, when the length of the hanging pillar and the exposed area of the hanging wall surrounding rock reach the critical caving value, the hanging pillar is gradually induced to cave and recovered from the first mining part of the stope. The caved hanging pillar ore falls into the open stope and is drawn out of the ore through the funnels together with the ore; The specific operation steps for inducing caving and recovering the hanging pillar are as follows: A hanging pillar drilling roadway is driven downward every 10m from the level haulage roadway in the upper level to induce caving and recover the hanging pillar. The end of the drilling roadway is not less than 5m away from the hanging pillar. Hanging pillar recovery blast holes are drilled from the drilling roadway towards the hanging pillar to be recovered, and charged section by section, and millisecond delay blasting is used. The caved hanging pillar is released through the funnel, and the overlying waste rock falls from the recovered hanging pillar part and fills part of the mined-out area; (5) The ore fallen in the stope and the ore of the induced caved hanging pillar are transported to the ore pass by a load-haul-dump machine, and then transported to the surface through the mine's transportation and hoisting system.

2. The combined mining method of induced caving of suspended roof pillars and sublevel caving with vertical deep-hole ore drawing according to claim 1, characterized in that, The specified roadway size for roof-suspended pillar drilling is 2.2×2.2 m 2 , the recovery blast hole length for roof-suspended pillar drilling is 10 - 20 m, and the millisecond delay time is 20 - 80 ms.

3. The combined mining method of induced caving of suspended roof pillars and sublevel caving with vertical deep holes according to claim 1, characterized in that, The scraper described in step (5) has a specification of 0.5 to 3 m 3 .

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