A method for recovering pillars in an upward drift small sublevel stoping sublevel open stope subsequent filling method

Abstract

The application discloses a method for upward access small sublevel stoping and sublevel open stope subsequent filling pillar, according to the arrangement of the sublevel open stope subsequent filling method, the pillar is divided into a top pillar along the ore body strike and an interval pillar perpendicular to the ore body strike; an extension access is arranged between the main line of each sublevel development of the ore room and the pillar to the pillar, as a bottom rock drilling roadway and an upper filling roadway for the sublevel stoping of the pillar; the ore room is non-cemented filling, shallow back mining is used in the bottom rock drilling roadway of the sublevel pillar to be mined, after the end, the upper sublevel filling roadway is used to fill the mined-out area, and after the filling body reaches the maintenance period, the upper sublevel pillar is mined according to the foregoing. The application arranges the access to the ore body based on the end of the sublevel open stope subsequent filling method, and the pillar between the stopes is upward access small sublevel stoped, so that the ore loss is reduced and the recovery rate is improved, and the application has the characteristics of safe and reliable stoping, high recovery rate and low stoping cost.

Description

Technical Field

[0001] This invention belongs to the field of mining engineering technology, and specifically relates to a method for pillar mining using an upward approach small-segment mining method with segmented open area subsequent backfilling, which is safe, reliable, has a high recovery rate, and low mining cost. Background Technology

[0002] Mineral resources, as non-renewable resources, are the foundation of economic development. However, with years of mining, some mines are experiencing resource depletion, making resource shortages increasingly prominent. Therefore, improving mineral resource recovery is crucial. Traditional underground mining primarily uses caving methods, but to improve recovery rates, there is a gradual shift towards backfilling mining. Backfilling mining refers to a mining method where backfill material is used to fill the goaf during ore extraction, transportation, and other operations. The purpose of backfilling is to support the rocks on both sides of the goaf and create a foundation for continued upper-level mining. Among these methods, the upward-entry layered backfilling mining method is currently one of the most widely used in both metallic and non-metallic mines. It is a bottom-up, roadway-based mining and backfilling method where the mining path operates under the naturally stabilized or supported roof of the ore. It is suitable for deposits where the ore and rock are not stable, but the ore body can generally ensure the stability of the mining path.

[0003] Subgrade stope backfilling, a type of backfilling mining method, mainly consists of two parts: stopes and pillars. In early applications, non-cemented materials such as waste rock and tailings were used to backfill the stopes. During stope recovery, to ensure stope stability, pillars of a certain thickness are reserved to support the stope roof and the non-cemented backfill material in adjacent stopes. After stope recovery and backfilling are completed, these pillars are no longer mined, resulting in the loss of mineral resources. Therefore, the recovery of these reserved safety pillars, stage horizontal interval pillars, and stope interval pillars is an important step in improving mine recovery rates.

[0004] In existing technologies, pillar mining mainly employs methods such as extraction, pillar cutting, artificial prop replacement, full backfilling followed by mining, and caving. Full backfilling followed by mining involves first backfilling the goaf, and then excavating within the backfill to mine the pillar. Because the goaf has multiple exit points after sublevel goaf mining with full backfilling, the number of retaining walls required for pillar mining is large, resulting in a significant workload. Furthermore, the goaf must be fully backfilled with high strength, increasing backfilling costs. The pillar mining process requires excavating and transporting large amounts of backfill material from within the backfill, leading to extensive preparatory work for the roadways within the backfill and increased support difficulties due to the poor stability of the backfill. Therefore, existing full backfilling followed by mining methods result in poor safety, complex mining processes, and high costs. In addition, other existing pillar mining methods generally suffer from poor mining safety and reliability. Although some methods can guarantee mining safety to some extent, they still have problems such as complex mining processes, low mining rates, and high mining costs.

[0005] In order to improve the recovery rate of mineral resources and solve the above-mentioned problems in the recovery of pillars in existing technologies, it is urgent to study a recovery method that is safe, reliable, has a high recovery rate, and low recovery cost. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method for constructing pillars using an upward-approach small-segment mining method with subsequent backfilling of the sub-valley, which offers safe and reliable mining, high recovery rate, and low mining cost.

[0007] The objective of this invention is achieved as follows: it includes steps such as pillar division, preparatory engineering layout, mining, and backfilling, specifically including:

[0008] A. Pillar division: Based on the layout of the sublevel open stope with subsequent backfilling, the pillars are divided into top pillars along the strike of the ore body and intermediate pillars perpendicular to the strike of the ore body.

[0009] B. Layout of the mining preparation project: Extend the main mining preparation roadway to the pillar at the corresponding position of the pillar in each segment of the stope formed by the segmented open area and subsequent backfilling method. This roadway serves as the bottom drilling roadway and the upper backfilling roadway during segmented mining of the pillar.

[0010] C. Mining and backfilling: The stope formed by the segmented stope backfilling method is backfilled with tailings in a non-cemented manner. Then, shallow-hole mining is carried out in the rock drilling roadway at the bottom of the segmented pillar to be mined. The single caving step distance of the shallow-hole mining is 5-6m. After the mining is completed, the backfilling roadway of the upper segment is used to backfill the mined stope of the lower segment. After the backfill body reaches the curing period, the pillar of the upper segment is mined again as described above.

[0011] The beneficial effects of this invention are:

[0012] 1. This invention addresses the issue of reserving pillars for support of the stope roof and tailings in continuous stope mining, which is necessary during continuous stope mining. After mining is completed, these pillars are no longer mined. This invention employs an upward-approach, small-section filling method for the pillars between stops. Furthermore, by utilizing the stope bottom preparation line and the corresponding pillar positions in the segmented stope filling method, an extended approach is arranged to the pillars. The pillars between each stope are mined using a shallow, step-by-step mining approach. After mining, waste rock is cemented and backfilled. Therefore, the approach layout is simple, the mining and backfilling processes are straightforward, and ore loss can be effectively reduced to improve the recovery rate.

[0013] 2. The approach route of the present invention is arranged at the position corresponding to the main line and the pillar at the bottom of the stope and extends to the pillar. Since the approach route extends along the pillar, it can not only reduce or even avoid the problem of multiple stope exits after the subgrade stope is subsequently backfilled, which would require the construction of a large number of retaining walls and thus a large amount of engineering work; it can also significantly reduce or even avoid the problem of the approach route needing to be excavated from the backfill body and transport a large amount of backfill body, which would result in a large amount of approach route preparation engineering in the backfill body, leading to high mining costs, and due to the poor stability of the backfill body, it would lead to greater difficulty in support and maintenance and poor mining safety and reliability.

[0014] 3. The present invention extends into the pillar with a pass width of 4-6m, and each side of the pillar has a reserved 0.8-1.2m wide ore wall. Because the stope in the sublevel stope backfilling method uses non-cemented tailings, voids are created during pillar mining. This causes the vertical stress of the upper rock mass of the pillar to transfer to the sidewalls of the pillar, resulting in stress concentration in the roof and sidewalls. This vertical stress is partially applied to the tailings, causing the tailings in the stope to experience maximum lateral pressure at the bottom of the stope due to the combined effects of their own weight and the vertical stress of the roof, thus achieving a certain degree of consolidation. The lateral pressure on the tailings in the middle of the stope in the vertical direction is relatively reduced, weakening the consolidation effect. The present invention, by reserving ore walls on both sides of the pass, can resist the influence of the mining space in the sublevel stope backfilling method on the lateral pressure of the tailings, preventing the collapse of the solidified tailings and ensuring the safety and reliability of pillar mining.

[0015] 4. This invention further employs shallow-hole mining, with cutting risers arranged at the ends of each pillar and slotted mining performed. The remaining mining utilizes waste rock cemented backfill material. Through the brittle expansion property of the waste rock, loose medium compression blasting is performed with the direction of the backfill as the free surface. The blasting step distance is set at 5-6m, which can effectively reduce blasting confinement. Secondly, the backfill is subjected to lateral compression by the blast, which can further compact it, thereby improving the self-support of the backfill when one side is exposed during the mining process.

[0016] In summary, this invention features safe and reliable mining, high recovery rate, and low mining cost. Attached Figure Description

[0017] Figure 1 This is a cross-sectional view of the ore body perpendicular to the strike of the present invention; (for) Figure 2 (AA-direction sectional view)

[0018] Figure 2 for Figure 1 CC-direction sectional view;

[0019] Figure 3 for Figure 1 DD section view;

[0020] Figure 4 for Figure 3 BB-axis rotation magnified view;

[0021] In the diagram: 1-Pillar, 2-Top pillar, 3-Interstitial pillar, 4-Drilling roadway, 5-Mining preparation trunk line, 6-Backfill roadway, 7-Backfill shaft, 8-Extension access road, 9-Exit access road, 10-Exit pass, 11-Reserved ore wall, 12-Through-vein transport roadway, 13-Shallow hole blast hole, 14-Uncemented backfill, 15-Cemented backfill. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this does not limit the present invention in any way. Any changes or substitutions made based on the teachings of the present invention shall fall within the protection scope of the present invention.

[0023] like Figure 1 and 2 As shown, the present invention includes the steps of pillar division, preparatory engineering layout, mining, and backfilling, specifically including:

[0024] A. Pillar division: Based on the layout of the sublevel open stope with subsequent backfilling, the pillars are divided into top pillars along the strike of the ore body and intermediate pillars perpendicular to the strike of the ore body.

[0025] B. Layout of the mining preparation project: Extend the main mining preparation roadway to the pillar at the corresponding position of the pillar in each segment of the stope formed by the segmented open area and subsequent backfilling method. This roadway serves as the bottom drilling roadway and the upper backfilling roadway during segmented mining of the pillar.

[0026] C. Mining and backfilling: The stope formed by the segmented stope backfilling method is backfilled with tailings in a non-cemented manner. Then, shallow-hole mining is carried out in the rock drilling roadway at the bottom of the segmented pillar to be mined. The single caving step distance of the shallow-hole mining is 5-6m. After the mining is completed, the backfilling roadway of the upper segment is used to backfill the mined stope of the lower segment. After the backfill body reaches the curing period, the pillar of the upper segment is mined again as described above.

[0027] The width of the pillar in step A is 6-8m; the width of the access road extending into the pillar in step B is 4-6m, and the pillars on both sides of the access road are reserved with a 0.8-1.2m wide ore wall.

[0028] In step B, firstly, at the corresponding positions of the main mining line and the inter-pillar in each segment of the stope formed by the segmented open area subsequent filling method, an extension path is arranged within the inter-pillar, serving as the bottom drilling roadway and the upper filling roadway during the segmented mining of the inter-pillar; then, at the corresponding positions of the main mining line and the top pillar in each segment, an extension path is arranged within the top pillar, serving as the bottom drilling roadway and the upper filling roadway during the segmented mining of the top pillar, and the extension path within the top pillar is connected to the extension path within the inter-pillar.

[0029] In step C, the mining width of the pillar to be mined is 4-6m and the height is 5-6m.

[0030] In step C, the excavation advance of the upper segment's filling roadway is consistent with the caving distance of the lower pillar and is completed ahead of the pillar's recovery.

[0031] In step C, the ends of each pillar are cut with raised access for backfilling, and the remaining parts are extracted by compression blasting using cemented backfill as the loose medium.

[0032] In step C, shallow hole small-step backward mining is adopted, and the height of the shallow hole is 4~6m. After each step of mining is completed, a backfilling retaining wall is arranged and the empty area of ​​the next mining section is filled.

[0033] In step C, within the same segment, two adjacent columns are considered as a mining area. First, the top column along the ore body strike within this area is mined. After the top column is backed back to the column, it is backed back from the upper end of the column to the lower boundary.

[0034] In step C, when the rock drilling tunnel is pulled open vertically to the top pillar within the inter-pillar, the bottom rock drilling tunnel is pulled open along the direction of the top pillar. The top pillar is then back-mined to the junction of the top pillar and the inter-pillar, and then the back-mining of the inter-pillar continues until the inter-pillar is back-mined to the footwall boundary.

[0035] The cemented backfill in step C is a mixture of cemented aggregate and tailings, and the strength of the cemented backfill is greater than 1.8 MPa. Example

[0036] A mine in Yunnan Province has a near-east-west trending ore body with an average vertical thickness of 18m. The ore body is regularly shaped and buried at a depth of 450-600m. It is mined using the sublevel stope backfilling method, with non-cement tailings used for backfilling. During the stope backfilling process, 8m-wide pillars are reserved between each stope to ensure safe mining. With continuous mining, the mineral resources are dwindling. To ensure a continuous and stable supply of ore and extend the mine's service life, it is necessary to recover the pillars. The following steps are proposed for pillar recovery:

[0037] S100: According to the layout of the segmented open stope and subsequent filling method stope, the ore pillar 1 is divided into the top pillar 2 along the ore body strike and the intermediate pillar 3 perpendicular to the ore body strike; and the drilling roadway 4 and the filling roadway 6 are arranged according to the strike of the ore pillar 1. The ore pillar 1 is 8m wide, the drilling roadway 4 and the filling roadway 6 are both 6m wide and 3m high, and a 1m wide ore wall is reserved on each side of the ore pillar 1.

[0038] S200: Based on the layout of the stope using the segmented stope and subsequent backfilling method, using the preparatory trunk line 5 arranged in each segment of the stope bottom, firstly, in the corresponding positions of the preparatory trunk line 5 and the inter-pillar 3 of each segment of the stope formed by the segmented stope and subsequent backfilling method, the access road extending inside the inter-pillar 3 is arranged as the bottom drilling roadway 4 and the upper backfilling roadway 6 during the segmented mining of the inter-pillar 3; then, in the corresponding positions of the preparatory trunk line 5 of each segment and the top pillar 2, the access road extending inside the top pillar 2 is arranged as the bottom drilling roadway 4 and the upper backfilling roadway 6 during the segmented mining of the top pillar 2, and the access road extending inside the top pillar 2 is connected to the access road extending inside the inter-pillar 3.

[0039] S300: The stope formed by the segmented open area subsequent backfilling method is backfilled with tailings without cementation. Then, shallow hole small step back mining is carried out in the rock drilling roadway 4 at the bottom of the segmented pillar (where the height of the shallow hole blast hole is 6m and the step distance of one blasting step is 6m). After each step back mining is completed, a backfill retaining wall is arranged, and the backfill roadway 6 of the upper segment is used to backfill the back mining area of ​​the lower segment. After the cemented backfill body 15 reaches the curing period, the pillar 1 of the upper segment is mined as described above.

[0040] In this process, cutting risers are arranged in the rock-drilling roadway 4 at the end of each pillar 1 to be mined for slotting mining, and the remaining part is mined by compression blasting with adjacent loose media using cemented backfill 15 as the free surface.

[0041] When mining pillar 1, within the same section, two adjacent sections of two inter-pillars 3 are considered as one mining area. First, the top pillar 2 along the ore body strike in this area is mined. After the top pillar 2 is backed back to the inter-pillar 3, it is backed back from the upper end of the inter-pillar 3 to the lower boundary.

[0042] When the rock drilling tunnel 4 is pulled open vertically within the inter-pillar 3 to the top pillar 2, the top pillar 2 is pulled open along the direction of the bottom rock drilling tunnel 4. The top pillar 2 is then back-mined to the junction of the top pillar 2 and the inter-pillar 3, and then the back-mining of the inter-pillar 3 is resumed until the inter-pillar 3 is back-mined to the lower boundary.

[0043] The upper filling roadway 6 is arranged in the manner of the bottom drilling roadway 4, corresponding to the positions of the upper section mining preparation line 5 and the inter-pillar 3 in the adjacent area along the strike direction. Each advance of the filling roadway 6 is equal to the mining step distance of the lower section pillar 1, and it is completed before the mining of pillar 1, until the bottom boundary of the vertically striking pillar 1 is reached, completing the mining of the inter-pillar 3 and the bottom pillar within one mining area. During mining, the excavation of the upper section filling roadway 6 closely follows the mining step distance of the lower pillar 1. Because the vertical distance between the upper and lower section drilling roadways 4 and the filling roadway 6 is not large, they should not be separated at once. After the mining and filling of pillar 1 in this area is completed, the upper filling roadway 6 is connected to the corresponding section mining preparation line 5, and the bottom drilling roadway 4 is mined using the upper section pillar 1.

[0044] After the lower segment pillar 1 is mined and backfilled, the upper segment pillar 1 will be mined. At this time, the backfilling roadway 6 will be fully opened as the lower segment pillar 1 is mined, and will serve as the bottom drilling roadway 4 for the upper segment pillar 1. The backfilling roadway 6 will be excavated in the bottom preparation line 5 of the upper segment stope in the manner described above, and the upper segment pillar 1 will be mined.

[0045] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method of recovering pillars in an up-raise short sublevel open stope subsequent filling method, characterised in that The method comprises pillar division, mining and preparation engineering arrangement, and filling steps, and specifically comprises: A, pillar division: according to the arrangement form of the sublevel open stope subsequent filling method, the pillars are divided into top pillars along the ore body strike and interval pillars perpendicular to the ore body strike; B, mining and preparation engineering arrangement: the extension drifts are arranged at the corresponding positions of the mining and preparation trunk lines of each sublevel of the ore room formed by the sublevel open stope subsequent filling method and the pillars, as the bottom rock drilling roadway and the upper filling roadway during the sublevel mining of the pillars; C, mining and filling: the ore room formed by the sublevel open stope subsequent filling method is filled with tailings for non-cemented filling, then shallow holes are used for mining in the rock drilling roadway at the bottom of the sublevel pillar to be mined, the step distance of the shallow hole mining is 5-6 m, after the mining is completed, the filling roadway of the upper sublevel is used to fill the mined-out area of the lower sublevel, and after the filling body reaches the maintenance period, the pillar mining of the upper sublevel is performed according to the foregoing. The method for mining the pillars of the sublevel open stope subsequent filling method according to the upward drift type small sublevel mining, characterized in that the pillar width in the A step is 6-8 m; the drift width extended into the pillar in the B step is 4-6 m, and each of the pillar on the two sides of the drift is provided with a 0.8-1.2 m wide wall. The method for mining the pillars of the sublevel open stope subsequent filling method according to the upward drift type small sublevel mining, characterized in that in the B step, the drifts extended in the interval pillars are arranged at the corresponding positions of the mining and preparation trunk lines of each sublevel of the ore room formed by the sublevel open stope subsequent filling method and the interval pillars, as the bottom rock drilling roadway and the upper filling roadway during the sublevel mining of the interval pillars; then the drifts extended in the top pillars are arranged at the corresponding positions of the mining and preparation trunk lines of each sublevel and the top pillars, as the bottom rock drilling roadway and the upper filling roadway during the sublevel mining of the top pillars, and the drifts extended in the top pillars are communicated with the drifts extended in the interval pillars.

2. The method according to claim 1, c h a r a c t e r i s e d i n that The mining width of the sublevel pillar to be mined in the C step is 4-6 m and the height is 5-6 m.

3. The method according to claim 1, c h a r a c t e r i s e d i n that The excavation length of the filling roadway of the upper sublevel in the C step is consistent with the step distance of the pillar mining and is completed in advance of the pillar mining.

4. A method of recovering pillars in an upper decline small sublevel open stope subsequent filling method as claimed in claim 1, 2 or 3, characterised in that The end of each pillar is arranged for cutting shaft slot mining and the remaining part is subjected to extrusion blasting mining with the cemented filling body as the loose medium.

5. A method of recovering pillars in an upper decline small sublevel open stope subsequent filling method as claimed in claim 4, characterised in that The C step adopts shallow hole small step distance reverse mining and the height of the shallow hole is 4-6 m, a filling retaining wall is arranged after each step distance mining and the mined-out area of the lower sublevel is filled.

6. A method of recovering pillars in an upper decline small sublevel open stope subsequent filling method as claimed in claim 5, characterised in that In the C step, two adjacent interval pillars in the same sublevel are taken as a mining area, the top pillars along the ore body strike in the area are mined first, and when the top pillars are mined to the interval pillars, the interval pillars are mined from the upper end of the interval pillars to the lower boundary.

7. A method of recovering pillars in an upper decline small sublevel open stope subsequent filling method as claimed in claim 6, characterised in that In the C step, when the rock drilling roadway is pulled along the vertical strike to the top pillar in the interval pillar, the top pillar is pulled along the strike to the bottom rock drilling roadway, the top pillar is mined to the junction of the top pillar and the interval pillar in a reverse manner, and then the mining of the interval pillar is started, until the interval pillar is mined to the lower boundary.

8. A method of recovering pillars in an upper decline small sublevel open stope subsequent filling method as claimed in claim 4, characterised in that The cemented filling body in the C step is a mixture of cemented aggregate and waste rock, and the strength of the cemented filling body is greater than 1.8 MPa.

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