Mining process suitable for fault fracture zone with hanging wall of ore body

Abstract

The invention discloses a mining process suitable for an ore body hanging wall as a fault fracture zone. The method relates to the technical field of ore extraction and comprises the following steps that S1, a stope is divided into a plurality of subsection stopes from bottom to top, and each subsection stope is further divided into a plurality of layered stopes from top to bottom; each layered stope is further divided into unit stopes; s2, arranging related mining preparation cutting projects; s3, starting from the lowermost layer, performing access stoping on the layered stope from bottom to top; a stoping inlet road is arranged along the trend of the ore body, and first-step and second-step interval stoping is carried out; s4, when the unit stopes adjacent to the fractured zone are mined, anchor cable grouting supporting is conducted on the fractured zone; and S5, when mining of a single layered stope is completed, filling is conducted on the layered stop.The collapse risk of a roof of a broken zone is effectively controlled through the layered stope division, interval stoping and anchor cable grouting supporting technologies, ore resource losses are reduced, meanwhile, the completeness of filling operation and the feasibility of stoping of adjacent ore bodies are guaranteed, and the mining efficiency is improved. And the method has remarkable safety and economic benefits.

Description

Technical Field

[0001] The present invention relates to the technical field of ore mining, in particular to a mining process suitable for an ore body whose upper wall is a fault fracture zone. Background Art

[0002] In the mining practices of many metal and non-metal mines in my country, a unique type of ore body exists, where the ore body's hanging wall is in direct contact with a fault fracture zone. This geological condition poses significant challenges to mining operations. When the ore in the mine is stripped away to expose the roof, the loose rock structure and poor stability of the fault fracture zone make it prone to instantaneous collapse. This roof instability not only causes serious roof falls, threatening the lives of underground workers and the safety of equipment, but also causes a large amount of rock from the fracture zone to mix with the ore during mining, resulting in the undesirable geological phenomenon of simultaneous mining and collapse. This makes normal mining operations impossible in the mine and significantly increases the mine depletion rate and ore loss rate. Furthermore, the irregular shape of the goaf caused by the roof collapse makes subsequent filling operations difficult to implement effectively, which in turn affects the normal mining of ore bodies in adjacent areas.

[0003] Currently, a conservative risk-avoidance strategy is commonly adopted for mining such ore bodies: a certain thickness of roof protection or isolation pillars is reserved when mining approaches the fracture zone, and ore recovery in the exposed fracture zone is actively abandoned. While this approach mitigates the risk of collapse, it results in the permanent loss of significant ore resources (typically, ore grades are higher near the altered zone at the interface between the ore and surrounding rock), severely impacting the mine's economic efficiency and resource utilization. Furthermore, this passive risk-avoidance approach fails to fundamentally address the stability issues of the fracture zone roof, hindering the advancement of mining technology. Summary of the Invention

[0004] The purpose of this application is to provide a mining process and support method suitable for the upper plate of the ore body as a fault fracture zone, which has the advantages of improving the stability of the fracture zone roof, reducing ore resource losses, reducing the depletion rate of the mining area and ensuring the effectiveness of filling operations.

[0005] The present application provides a mining process suitable for an ore body with a fault fracture zone as its upper plate, and the technical solution is as follows: comprising the following steps: S1, dividing the mining field into several segmented mining fields from bottom to top, and each segmented mining field is further divided into several layered mining fields from top to bottom; each layered mining field is further divided into unit mining fields; S2, arranging relevant mining and cutting projects; S3, starting from the lowest layer, implementing route mining for the layered mining fields from bottom to top; the mining route is arranged along the direction of the ore body, and one or two steps of interval mining are carried out; S4, when mining the unit mining field adjacent to the fracture zone, the fracture zone is supported by anchor grouting; S5, when a single layered mining field is mined, the layered mining field is filled.

[0006] Furthermore, the present application also proposes that the mining and cutting project in step S2 includes: off-vein tunnels, ramps, segmented level tunnels, layered connecting tunnels, filling return air shafts, chutes and bottom tunnels.

[0007] Furthermore, the present application also proposes that, in step S3, mining is first carried out from the unit stope on the side away from the broken zone.

[0008] Furthermore, the present application also proposes that in step S4, before mining the unit stope adjacent to the broken zone, horizontal anchor holes are constructed along the stope direction toward the broken zone on the side of the unit stope that has just been mined but not filled. The anchor holes pass through the broken rock layer to reach the stable rock layer. After the anchor hole construction is completed, the horizontal anchor cable is installed and pressurized grouting is carried out. While achieving coupling between the anchor cable and the surrounding rock, the cracks in the stope roof are filled by grouting to form a stable support.

[0009] Furthermore, the present application also proposes that the free end of the horizontal anchor cable needs to be fixed on the unit mine filling body that has been completed in the same layered mine. After the construction of this process is completed, the newly mined unit mine can be filled, so that the free end of the horizontal long anchor cable and the mine filling body are coupled, thereby forming support for the roof after the mine adjacent to the broken zone is exposed; then the mining and ore extraction operations of the unit mine adjacent to the broken zone are carried out.

[0010] Furthermore, the present application also proposes that in step S4, after completing the mining and ore extraction operations of the unit mine adjacent to the broken zone, anchor holes are constructed in the vertical direction at the junction of the ore on the roof of the unit mine and the broken zone. The anchor holes need to pass through the broken rock layer to the stable rock layer of the surrounding rock; then the vertical anchor cables are installed and pressurized grouting is performed in the anchor cable holes to achieve coupling of the vertical anchor cables and the rock mass, and at the same time, the cracks in the side wall of the mine located directly above are filled.

[0011] From the above, it can be seen that the present application provides a mining process suitable for the upper plate of the ore body being a fault fracture zone. Through layered mining area division, interval mining and anchor grouting support technology, it can effectively control the risk of roof collapse in the fracture zone, reduce the loss of ore resources, and at the same time ensure the integrity of the filling operation and the feasibility of mining of adjacent ore bodies, with significant safety and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic diagram of a mining process applicable to an ore body with a fault fracture zone in the hanging wall;

[0013] Figure 2 yes Figure 1 AA section view in;

[0014] Figure 3 yes Figure 2 BB cross-section view in. DETAILED DESCRIPTION

[0015] The following is combined with Figure 1-3 This application is described in further detail.

[0016] In existing technology, portions of ore bodies 4 in metal and nonmetal mines are located beneath a fault fracture zone 5, with the roof of the ore body 4 consisting of a fractured rock layer. To mitigate the risk of roof collapse, traditional methods halt mining early in areas near the fracture zone 5, resulting in inadequate ore recovery. While this conservative mining strategy reduces safety incidents, it significantly reduces the recovery rate of the ore body 4, impacting the mine's overall economic efficiency.

[0017] To address the aforementioned issues, and to address the vulnerability of exposed roof slabs in Fracture Zone 5 to collapse, we first considered how to control the exposed roof area. By dividing the stope into multiple mining units, we gradually reduced the excavation span and reduced stress concentration in the surrounding rock. Secondly, we needed to address the poor self-stability of the rock mass in Fracture Zone 5 by adopting a strategy of coordinated load-bearing through active support and backfill. Finally, we needed to optimize the mining sequence, using intermittent stoping to form temporary support structures to provide stability for subsequent operations.

[0018] Therefore, this application proposes a mining process comprising the following steps:

[0019] S1. Divide the stope into several sub-stopes from bottom to top, and each sub-stope is further divided into several layered stopes from top to bottom; each layered stope is further divided into unit stopes;

[0020] S2. Arrange relevant mining and cutting projects, including off-vein tunnels, ramps, segmented level tunnels, layered connecting tunnels, filling return air shafts, chute shafts, and bottom tunnels;

[0021] Among them, extra-vein tunnels refer to transportation channels arranged in the surrounding rock of the ore body 4. Specifically, they can be achieved by excavating tunnels in stable rock strata along the strike of the ore body 4, avoiding the fracture zone 5 to reduce the risk of surrounding rock disturbance. Among them, ramps refer to inclined channels connecting different mining levels. Specifically, they can be implemented using a switchback ramp structure, forming an independent personnel and equipment transportation system. Among them, segmented drifts refer to horizontal transportation channels arranged along the strike of the ore body 4. Specifically, they can be implemented in the form of parallel drifts spaced at different mining sections, providing ore transportation routes for the stratified stopes. Among them, stratified connecting drifts refer to vertical channels connecting adjacent sections. Specifically, they can be implemented by connecting upper and lower segmented drifts with vertical or inclined drifts, forming a three-dimensional transportation network. Among them, filling return air shafts refer to vertical channels that combine filling piping layout and ventilation functions. Specifically, they can be implemented using precast concrete support structures to simultaneously meet the needs of filling operations and air circulation. Among them, chutes refer to vertical channels dedicated to ore transfer. Specifically, they can be implemented by setting up buffer platforms in sections to shorten the distance of ore transportation. Among them, the bottom tunnel refers to the tunnel at the starting layer of the mining operation. Specifically, the pre-splitting blasting technology can be used to form the initial free surface to create an operating space for subsequent mining.

[0022] S3, starting from the lowest layer, carry out route mining in the stratified stope from bottom to top; the mining route is arranged along the strike of ore body 4, and the first and second steps of interval mining are carried out;

[0023] In the mining operation, the unit stope far away from the fracture zone 5 is preferably selected as the starting mining area, and then the mining sequence is gradually advanced towards the fracture zone 5;

[0024] Before mining the unit stope adjacent to the fracture zone 5, on the side of the unit stope that has just been mined but not filled, horizontal anchor cable holes 6 are constructed along the strike of the stope toward the fracture zone 5. The anchor cable holes pass through the fractured rock strata to reach the stable rock strata. After the anchor cable holes are constructed, the horizontal anchor cable 6 is installed and pressurized grouting is performed. While coupling the anchor cable with the surrounding rock, the cracks in the stope roof are filled by grouting to form a stable support.

[0025] The free end of the horizontal anchor cable 6 needs to be fixed to the filling body of the unit stope that has been filled in the same layered stope. After this process is completed, the newly mined unit stope can be filled, so that the free end of the horizontal long anchor cable is coupled with the stope filling body, thereby forming support for the roof after the stope adjacent to the fracture zone 5 is exposed; then the mining and ore extraction operation of the unit stope adjacent to the fracture zone 5 is carried out;

[0026] After completing the mining operation of the unit mine adjacent to the crushing zone 5, an anchor hole is constructed in the vertical direction at the junction of the roof ore of the unit mine and the crushing zone 5. The anchor hole needs to pass through the crushed rock layer to the stable rock layer of the surrounding rock; then the vertical anchor cable 7 is installed and pressurized grouting is performed in the anchor hole to achieve the coupling of the vertical anchor cable 7 and the rock mass, and at the same time, the cracks in the side wall of the mine located directly above are filled.

[0027] Combined with attachment Figure 1 The stope division is shown in the figure, where the first digit is the layer number and the second digit is the stope number. For example, stope 2-3 is the third stope in the second layer. The mining method uses the first layer, then the second layer, and finally the third layer for the stope. The order of mining within a stope is to first mine the first layer, then the second layer, and finally the third layer. The order of mining within a layer is to first mine stope 1, then stope 2, and finally stope 3. The figure shows a single-segment diagram of this mining method. The overall mining order from front to back is ①②③④⑤⑥⑦⑧⑨.

[0028] The implementation method of this process is as follows (taking the stope numbered ③ as an example), when the first layer mining operation is carried out, after the mining and filling cycles of stopes ① and ② are completed, stope ③ is mined. After the ore extraction operation of stope ③ is completed, anchor holes are constructed at the intersection of the ore in the stope roof and the broken zone 5 (i.e. the mining boundary of the upper stope ⑥) along the stope direction at a spacing of 2m. The anchor holes need to pass through the broken rock layer to the stable rock layer of the surrounding rock. After the anchor cables are installed, the anchor holes are pressurized and grouting is carried out to achieve coupling between the anchor cables and the rock mass.

[0029] At the same time, the cracks on the side walls of No. 6 stope were filled.

[0030] After the anchor cable construction is completed, the No. ③ mining area is closed and filled, and the filling is required to connect to the top. At this time, the pre-support of the side of the No. ⑥ mining area is completed. After this step is completed, the first layer of mining is complete, and the second layer of mining begins. First, stope No. 4 is mined. After the mining and filling cycle in stope No. 5 is mined. After the ore is extracted from stope No. 5, six horizontal anchor holes are constructed on the side of stope No. 5 near stope No. 6, along the stope's direction, at 2m intervals toward stope No. 6. (They are required to be staggered with the anchor holes constructed in stope No. 3 and pass through the broken rock strata to reach the stable rock strata.) After the anchor holes are constructed, the anchors are installed and pressurized grouting is performed. While coupling the anchors with the surrounding rock, the grouting fills the cracks in the stope roof, forming a stable support. At the same time, the free ends of the anchors need to be fixed to the backfill in stope No. 4. After this process is completed, stope No. 5 can be backfilled, so that the free ends of the long horizontal anchors couple with the backfill in stope No. 5, providing support for the stope No. 6 roof after stope No. 6 is uncovered. At this point, the side and roof pre-support process for stope No. 6 is complete.

[0031] S4. When mining the unit stope adjacent to the broken zone 5, the broken zone 5 is supported by anchor grouting; when the single layered stope is mined, the layered stope is filled.

[0032] Compared to existing technologies, traditional passive support methods typically involve temporary support after the roof is exposed, resulting in delayed support and limited reinforcement coverage. This solution, however, constructs an active support system before the fracture zone 5 is exposed in the stope. Horizontal anchor cables 6 are used to pre-emptively constrain the displacement of the fractured rock mass. Combined with grouting to eliminate potential collapse spaces, this proactive reinforcement is achieved. Compared to conventional methods that simply use shotcrete sealing, this technology brings support operations forward to the mining preparation stage, effectively mitigating the risk of roof collapse.

[0033] Through the above-mentioned technical solution, this application forms a stable anchoring-grouting composite support structure before exposing the fracture zone 5, preventing the roof from collapsing during mining and ensuring safe mining conditions in the stope. This technology also reduces ore depletion by filling the cracks and provides a complete stope space for subsequent filling operations, avoiding the problem of stope abandonment due to roof collapse, and significantly improving the mining rate in the area adjacent to the fracture zone 5.

[0034] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A mining process suitable for a ore body with a fault fracture zone as its hanging wall, characterized in that The steps include: S1. Divide the stope into several sub-stopes from bottom to top, and each sub-stope is further divided into several layered stopes from top to bottom; each layered stope is further divided into unit stopes; S2. Arrange relevant mining and cutting projects; S3. Starting from the lowest layer, the entry point is mined from bottom to top in the stratified stope; the entry point is arranged along the ore body, and one or two steps of interval mining are carried out; S4. When mining the unit stope adjacent to the broken zone, anchor grouting support is carried out on the broken zone; S5. When a single layer stope is mined, the layer stope is filled.

2. The mining process according to claim 1, which is suitable for a mining area with a fault fracture zone as the hanging wall of an ore body, is characterized in that: The mining and cutting works in step S2 include: outer-vein tunnels, ramps, segmented level tunnels, layered connecting tunnels, filling return air shafts, chutes and bottom tunnels.

3. The mining process according to claim 2, which is applicable to a ore body with a fault fracture zone as its hanging wall, is characterized in that: In step S3, mining is first performed from the unit stope away from the side of the broken zone.

4. The mining process according to claim 3, which is applicable to a mining area where the upper wall of an ore body is a fault fracture zone, is characterized in that: In step S4, before mining the unit stope adjacent to the broken zone, horizontal anchor holes are constructed along the stope direction toward the broken zone on the side of the unit stope that has just been mined but not filled. The anchor holes pass through the broken rock layer to reach the stable rock layer. After the anchor hole construction is completed, the horizontal anchor cable is installed and pressurized grouting is carried out. While coupling the anchor cable with the surrounding rock, the cracks in the stope roof are filled by grouting to form a stable support.

5. The mining process according to claim 4, which is applicable to a mining area where the upper wall of an ore body is a fault fracture zone, is characterized in that: The free end of the above-mentioned horizontal anchor cable needs to be fixed on the unit stope filling body that has been completed in the same layered stope. After the construction of this process is completed, the newly mined unit stope can be filled, so that the free end of the horizontal long anchor cable and the stope filling body are coupled, thereby forming support for the roof after the stope adjacent to the broken zone is exposed; then the mining and ore extraction operations of the unit stope adjacent to the broken zone are carried out.

6. The mining process according to claim 4, which is applicable to a ore body with a fault fracture zone as its hanging wall, is characterized in that: In step S4, after completing the mining operation of the unit mine adjacent to the broken zone, an anchor hole is constructed in the vertical direction at the junction of the ore roof and the broken zone of the unit mine. The anchor hole needs to pass through the broken rock layer to the stable rock layer of the surrounding rock; then the vertical anchor cable is installed and pressurized grouting is performed in the anchor cable hole to achieve the coupling of the vertical anchor cable and the rock mass, and at the same time, the cracks in the side wall of the mine located directly above are filled.

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