Staged ascending pillar-free large-diameter deep-hole lateral caving subsequent filling mining method

Abstract

The invention relates to the technical field of underground mining of metal ore deposits, in particular to a staged ascending pillar-free large-diameter deep-hole lateral caving subsequent filling mining method, which comprises the following steps of: dividing a steeply inclined medium-thickness ore body into a plurality of stages, and dividing large and small stopes in the stages without leaving pillars; digging a flat-bottom ore removal structure at the bottom of the stope, and digging a rock drilling chamber at the bottom of the stope at the upper stage; digging a cutting well at the end part of the stope and expanding the cutting well into a cutting groove; large-diameter parallel deep holes are drilled downwards in the rock drilling chamber, and lateral ore caving is carried out with cutting grooves as free faces; the caved ore is transported out by a carry-scraper through the flat-bottom ore removal structure; and the stope goaf is subjected to subsequent cemented filling. The small stopes are firstly stoped and filled with the 1: 4 full-tailing cementing material, and after the small stopes are solidified, the large stopes are stoped and filled with the 1: 20 full-tailing cementing material. The method has the characteristic of ascending stoping among stages, and has the advantages that pillar-free continuous stoping is realized, and the rock drilling chamber is used as a flat bottom ore removal structure to be reused.

Description

Technical Field

[0001] This invention relates to the field of underground mining technology for metal deposits, specifically to a staged, pillarless, large-diameter deep-hole lateral caving followed by backfilling mining method, applicable to inter-stage upward mining of steeply dipping, medium-thick ore bodies with indistinct contact zones and stable or more stable ore bodies. Background Technology

[0002] With the increasing depletion of easily accessible shallow resources, metal mining activities are gradually shifting towards deeper areas. This shift presents mines with the dual challenges of increased deep-seated ground pressure and stricter environmental requirements. Backfilling mining, which utilizes tailings and other mine solid waste to control ground pressure and reduce surface tailings accumulation, has become the mainstream trend in deep, green mining methods. For the mining of steeply dipping, medium-thick, and thick ore bodies, large-diameter deep-hole lateral caving followed by backfilling mining is favored by mining companies with stable or steeply dipping, medium-thick ore bodies due to its advantages such as high production capacity, high degree of mechanization, good operational safety, and low overall backfilling cost.

[0003] Currently, there are two main schemes for large-diameter deep-hole lateral caving followed by backfilling mining in the industry. One is the pillarless continuous mining scheme developed by Gu Desheng, Wu Aixiang, etc. This scheme divides the ore block within a stage into two zones, with ore walls between the zones. The bottom structure adopts a flat-bottomed structure without secondary crushing, and five double-platform combined vibratory machines are installed to assist in ore extraction, resulting in good continuity of ore block mining. The second is a large-diameter deep-hole lateral caving followed by backfilling mining scheme that has evolved from the pillarless continuous mining scheme, with pillars and top pillars left. The pillars and top pillars, together with the backfill, support the surrounding rock. Both schemes adopt a top-down mining sequence between stages. The former has high requirements for backfilling and roof connection work, and the drilling chamber cannot be reused; the latter's pillars and top pillars, if not recovered, will result in the loss of some mineral resources, while recovery is extremely difficult due to ore and rock fracturing caused by ground stress. Furthermore, the drilling chamber cannot be reused. Summary of the Invention

[0004] The purpose of this invention is to provide a phased, pillarless, large-diameter deep-hole lateral caving mining method followed by backfilling, which differs from the aforementioned two schemes of inter-phase downward mining. This method employs an inter-phase upward mining sequence. Within each phase, several small and large stopes are continuously divided along the strike, without intervening pillars or roof pillars. The stope structures of the small and large stopes are similar, and the mining processes are analogous. During mining, no requirements are placed on the backfilling and roof connection work in the small and large stopes. The small stopes are advanced by one phase and backfilled with 1:4 tailings cementitious material. After solidification, the large stopes are mined and backfilled with 1:20 tailings cementitious material. The ore section is mined in one step, with no residual pillars requiring secondary recovery. The drilling chamber is reused as a flat-bottomed ore extraction structure during the previous phase mining, thereby achieving continuous, pillarless, phased upward mining of steeply dipping, medium-thick ore bodies.

[0005] To achieve the above objectives, the technical solution of the present invention is: to provide a staged upward-moving pillarless large-diameter deep-hole lateral caving followed by backfilling mining method, applicable to inter-stage upward-moving mining of steeply dipping medium-thick ore bodies with indistinct contact zones and stable or above-standard ore bodies, comprising the following steps: a. Ore block division: The steeply dipping, medium-thick ore body is divided into several stages along the vertical direction, with a stage height of 50 m to 60 m. Within each stage, several small and large mining areas are continuously divided along the strike. The strike length of the small mining area is 10 m to 15 m, and the strike length of the large mining area is 30 m to 50 m. No top pillars, bottom pillars, or interstitial pillars are left within each stage. b. Mining and cutting operations: A cross-cutting roadway is excavated from the lower footwall stage transport roadway to the upper footwall return airway. Through the cross-cutting roadway, an ore-exit transport roadway is excavated along the strike of the lower footwall surrounding rock. A bottom-pull roadway is excavated at the bottom of the stope. Ore-exit access roads are excavated from the ore-exit transport roadway at regular intervals, connecting to the bottom-pull roadway. At the bottom of the upper stage, a cross-cutting roadway is excavated from the stage transport roadway, connecting to the upper footwall return airway. Drilling chambers are excavated, with a width exceeding the stope width by 0.5 m and a height of 4 m. Temporary 3 m × 3 m support pillars are provided on the roof of the drilling chambers as needed to ensure the safety of drilling and blasting operations. These drilling chambers also serve as flat-bottom ore-exit structures during the upper stage mining and are reused. At the end of the stope mining, a cutting riser is excavated and expanded into a cutting groove. The bottom-pull roadway is pre-formed into a flat-bottom ore-exit structure using shallow-hole blasting as the lateral caving progresses in the stope. c. Mining work: Drill large-diameter deep holes of 110 mm to 160 mm downward from the bottom plate of the self-drilled rock chamber. The blast holes are drilled in one go and blasted in a backward segmented charge. Lateral caving is carried out with the cutting groove as the free surface. The caving ore is transported out by a remote-controlled loader through the flat-bottom structure. d. After the mining is completed, the goaf is filled with tailings cementitious material with a ash-sand ratio of 1:4. After the filling material solidifies, the adjacent large mining area is mined again. The goaf of the large mining area is filled with tailings cementitious material with a ash-sand ratio of 1:20. During the mining of the large mining area, the high-strength filling material formed after the small mining area is filled is used to control the ground pressure in the mining area. e. Each stage is mined sequentially from bottom to top to achieve continuous mining without pillars as the stage moves upward.

[0006] The temporary anchor points retained along the direction of the center of the drilling chamber are recovered along with the ore during blasting.

[0007] The large-diameter deep hole is a vertical downward hole, with a depth that penetrates the entire stage height and reaches the top of the bottom roadway.

[0008] The uniaxial compressive strength of the backfill in small mining areas is ≥ 2 MPa after 28 days, while the uniaxial compressive strength of the backfill in large mining areas is 0.5 MPa to 1 MPa after 28 days.

[0009] The cross-sectional dimensions of the aforementioned stage transport roadway, bottom roadway, ore exit access roadway, and ore exit transport roadway are 3.5m×3.5m, 2.5m×3.5m, 3m×3m, and 3m×3m, respectively.

[0010] The key technical features of this invention are: 1. Inter-stage upward mining sequence; 2. Without leaving top pillars, bottom pillars, or intermediate pillars, continuous mining without pillars is achieved between stopes, significantly improving the ore recovery rate; 3. The drilling chamber can be reused as the bottom ore extraction space of the previous stage of the mining area, reducing the amount of preparation work. 4. Small stopes are filled with high-strength cemented backfill, which plays a major role in controlling ground pressure in stopes; large stopes are filled with low-strength cemented backfill, which can effectively reduce backfilling costs; there are no requirements for backfilling and roof connection during the upward mining process, and the roof of the stope in the last stage is protected by measures such as roof slope.

[0011] 5. The mining area has a large production capacity, low labor intensity, and a high degree of mechanization. Attached Figure Description

[0012] Figure 1 This is a cross-sectional view of the phased upward pillarless large-diameter deep hole lateral caving followed by backfilling mining method I-I described in this invention.

[0013] Figure 2 This is a cross-sectional view of the phased upward pillarless large-diameter deep hole lateral caving followed by backfilling mining method II-II described in this invention.

[0014] Figure 3This is a cross-sectional view of the phased upward pillarless large-diameter deep hole lateral caving followed by backfilling mining method III-III described in this invention.

[0015] Figure 4 This is a cross-sectional view of the IV-IV section of the phased upward pillarless large-diameter deep-hole lateral caving followed by backfilling mining method described in this invention.

[0016] The following are marked on the map: Stage transport roadway 1, hanging wall return airway 2, through-vein roadway 3, drilling chamber 4, bottom pull roadway 5, ore extraction transport roadway 6, ore extraction access road 7, temporary support pillar 8, backfill retaining wall 9, large diameter deep hole 10, fully cemented tailings backfill 11, surrounding rock 12, small stope 13, large stope 14. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0018] like Figures 1 to 4 As shown, an example of the staged upward pillarless large-diameter deep-hole lateral caving followed by backfilling mining method described in this invention includes the following steps: S1. Mineral block division: The ore body is divided into several production stages along the vertical direction, with a stage height of 60m. Within each stage, the ore body is divided into several continuously arranged large mining areas 14 and small mining areas 13 along the strike. The length of small mining area 13 along the strike is 15m, and the length of large mining area 14 along the strike is 50m. S2. Mining and Cutting Operations: In the stable surrounding rock of the ore body's footwall, the ore body is traversed from the stage transport roadway 1 through the cross-cut roadway 3. An ore transport roadway 6, with a cross-section of 3.5m × 3.5m, is excavated along the strike outside the footwall vein as the ore transport channel. At the bottom of the stope, a bottom-pulling roadway 5, with a cross-section of 2.5m × 3.5m, is excavated along the strike. From the ore transport roadway 6 towards the ore body, an ore access roadway 7, with a cross-section of 3m × 3m, is excavated every 10m, connecting with the bottom-pulling roadway 5. At the bottom of the upper stage, the cross-cut roadway 3 is excavated from the stage transport roadway 1, connecting to the upper hanging return airway 2, and a drilling chamber 4 is excavated. The drilling chamber 4 is 4m high, and its width covers the entire thickness of the ore body, widening by 0.5m on each side of the footwall and hanging wall, for a total width of 13m. To ensure the stability of the roof of the large-span drilling chamber 4, several irregular temporary support pillars 8 are retained along the strike in the center of the drilling chamber 4. The temporary support pillars 8 are approximately 3m x 3m in size and serve only as temporary support during drilling; they will be recovered during blasting. At the head of the mining operation, an AT2000 riser is used to drill and blast, forming a cutting riser and expanding it to create a cutting groove. As the lateral caving progresses during mining, the bottom roadway 5 is pre-formed with shallow-hole blasting to create a flat-bottomed ore-extraction structure. S3. Mining Process Layout: In drilling chamber 4, a large-diameter deep hole 10 (diameter Φ110mm) is drilled vertically downwards using a KQG-150 high-pressure down-the-hole drill rig. The blast hole penetrates the entire stage height, reaching the roof of the bottom-pull roadway 5. Lateral caving is carried out using the cutting groove at the end of the stope as a free face. The caving ore falls into the flat-bottomed ore extraction structure at the bottom and is transported by a remote-controlled loader through the ore extraction access roadway 7 to the ore extraction transport roadway 6, unloaded into the ore pass, and lowered into the rail-guided stage transport roadway for transportation out. After ore extraction is completed, a backfilling retaining wall 9 is constructed on the ore extraction access roadway 7 and the cross-cutting roadway 3. Full-grade tailings cemented backfill material is pumped to the goaf through the upper backfilling pipeline. The small stope is mined first and backfilled with high-grade 1:4 full-grade tailings cemented material. After the backfill material solidifies, the large stope is mined and backfilled with low-grade 1:20 full-grade tailings cemented material.

[0019] The above specific embodiments are only used to illustrate the present invention and are not intended to limit the present invention. Any equivalent substitutions or modifications made to the structural form, parameter values ​​and process steps of the present invention without departing from the spirit and substance of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A staged, pillarless, large-diameter deep-hole lateral caving followed by backfilling mining method, characterized in that, This method is applicable to inter-stage upward mining of steeply dipping, medium-thick ore bodies with indistinct contact zones and stable or more robust ore masses, and includes the following steps: a. Ore block division: The steeply dipping, medium-thick ore body is divided into several stages along the vertical direction, with a stage height of 50 m to 60 m. Within each stage, several small and large mining areas are continuously divided along the strike. The strike length of the small mining area is 10 m to 15 m, and the strike length of the large mining area is 30 m to 50 m. No top pillars, bottom pillars, or interstitial pillars are left within each stage. b. Mining and cutting operations: A cross-cutting roadway is excavated from the lower footwall stage transport roadway to the upper footwall return airway. Through the cross-cutting roadway, an ore-exit transport roadway is excavated along the strike of the lower footwall surrounding rock. A bottom-pull roadway is excavated at the bottom of the stope. Ore-exit access roads are excavated from the ore-exit transport roadway at regular intervals, connecting to the bottom-pull roadway. At the bottom of the upper stage, a cross-cutting roadway is excavated from the stage transport roadway, connecting to the upper footwall return airway. Drilling chambers are excavated, with a width exceeding the stope width by 0.5 m and a height of 4 m. Temporary 3 m × 3 m support pillars are provided on the roof of the drilling chambers as needed to ensure the safety of drilling and blasting operations. These drilling chambers also serve as flat-bottom ore-exit structures during the upper stage mining and are reused. At the end of the stope mining, a cutting riser is excavated and expanded into a cutting groove. The bottom-pull roadway is pre-formed into a flat-bottom ore-exit structure using shallow-hole blasting as the lateral caving progresses in the stope. c. Mining work: Drill large-diameter deep holes of 110 mm to 160 mm downward from the bottom plate of the self-drilled rock chamber. The blast holes are drilled in one go and blasted in a backward segmented charge. Lateral caving is carried out with the cutting groove as the free surface. The caving ore is transported out by a remote-controlled loader through the flat-bottom structure. d. After the mining is completed, the goaf is filled with tailings cementitious material with a ash-sand ratio of 1:

4. After the filling material solidifies, the adjacent large mining area is mined again. The goaf of the large mining area is filled with tailings cementitious material with a ash-sand ratio of 1:

20. During the mining of the large mining area, the high-strength filling material formed after the small mining area is filled is used to control the ground pressure in the mining area. e. Each stage is mined sequentially from bottom to top to achieve continuous mining without pillars as the stage moves upward.

2. The method according to claim 1, characterized in that: The temporary anchor points retained along the direction of the center of the drilling chamber are recovered along with the ore during blasting.

3. The method according to claim 1 or 2, characterized in that: The large-diameter deep hole is a vertical downward hole, with a depth that penetrates the entire stage height and reaches the top of the bottom roadway.

4. The method according to any one of claims 1-3, characterized in that: The uniaxial compressive strength of the backfill in small mining areas is ≥ 2 MPa after 28 days, while the uniaxial compressive strength of the backfill in large mining areas is 0.5 MPa to 1 MPa after 28 days.

5. The method according to any one of claims 1-4, characterized in that: The cross-sectional dimensions of the stage transport roadway, bottom roadway, ore exit access roadway, and ore exit transport roadway are 3.5m×3.5m, 2.5m×3.5m, 3m×3m, and 3m×3m, respectively.

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