Optimization of Mining Method for Volcanic Mine in Ancient Mining Area of ​​a Mine

0 mine overview

An important lead-zinc ore mining high-grade, long history of mining, due to the exploitation of different periods, the remains of ancient underground mined-out area, illegal mining of modern people mined-out area, and new mined-out area currently mined. The mining industry did not effectively treat the goaf in the early stage of mining. Due to the influence of the goaf, the underground stope collapsed, and a large amount of mineral resources could not be mined under the goaf. With the increase of the planned annual output and the deepening of the mining stage, the goaf in the upper stage has caused great safety hazards to the mining operation in the next stage [1]. In order to produce safety and complete design output, the mining company plans to treat the goaf and maximize the exploitation of resources, and rationally extract the troughs in the ancient mining area. According to safety feasibility, technical reliability, and economic rationality, select the appropriate mining method to treat the goaf and the mining trough.

1 safety feasibility
The corrugated ore is a filling body of the goaf, and is mixed with the collapsed mined-out pillars. It is a mixture of ancient mining and smelting slag and sulfide ore by hydraulic, oxidizing and self-pressing. The grade is 18% and has the economic value of recycling. The ore is loosely broken and extremely unstable. The mining has a great influence on the surface subsidence. Some of the residual ore deposits are yellow sand. The situation is unknown. The distribution of surrounding rock structure and mechanical properties parameters is not systematically studied. Due to the broken ore, the exposed area is very small during the mining process, and the roof may be generated; the residual ore may have a stabilizing effect in the goaf, and the mining may cause large-scale surface subsidence; the occurrence of the roof yellow sand in the mining process is unknown, and the sand may be generated. Drown equipment and personnel. There are civil mining areas around the residual mines, and the situation is unclear. Mining may cause flooding accidents in the mining areas and the connected surface water.
For the hazards of goafs and subsidence areas, the literature [2] proposed that the reconstruction of the mining environment must be carried out first, and the reliability of the mining safety should be ensured by the stability of the artificial structure; the exposed area should be strictly controlled during the mining process; At the time, the mining environment can be reconstructed by grouting, and the goaf around the working face should be pre-filled to ensure the stability of the mining roadway. At the same time, Chen Qingfa and others proposed a synergistic utilization mechanism for goaf [3-5], which is different from the traditional methods of filling, caving, support, and sealing in the goaf, and utilizes the goaf while maintaining the stability of the goaf. For example, as a part of the engineering roadway, or stacked mine solid waste.
Basic requirements for mining methods for residual ore mining: Establish good and safe working conditions; fully, rationally and efficiently exploit underground mineral resources.
Large production capacity, high labor productivity; low production cost and high production efficiency.
Based on the above points, there are four types of mining methods for selecting residual ore: stratified caving method, upward approach filling method, approach bracket filling method and down stratified cement filling mining method. This paper will compare the four methods and select a reasonable method for mining the trough.
2 technical reliability
2.1 Comparison of stratified caving method and filling method
For the mining of the corrugated ore, the ore is extremely unstable, and the mining of the broken loose ore body can be achieved by the stratified caving mining method, the downward stratified cementing filling method, the upward approach filling method and the box bracket filling method.
The stratified caving mining method is operated under the artificial false top, and the mining is carried out from top to bottom. The literature [6-8] studied the practical case of the caving method in the goaf, and confirmed the feasibility of the caving method for the general goaf. If the goaf is not pre-processed during the operation, the artificial false top cannot be stabilized due to the existence of the goaf, and the false top and its cover will fall into the gob. Therefore, the mined area must be backfilled before mining, and the false roof should be supported in time during the mining process. If the backfilling is dry filling, when returning to the goaf, the backing filler will naturally spread out at the slope of the natural rest angle, which is not easy to control when supporting the false top; in addition, because the support is on the loose rock mass, in the same It is difficult to ensure that the false top pillar does not sink when a layered mining is carried out, thus posing a safety hazard. Therefore, it is best to use a cemented filler to treat the goaf first.
Stratified caving method After each layered ore is produced, the overlying falling rock is moved down to fill the mining area. For the mining of the mine trough, the upper part is the goaf and the weak stratum; the mining activities will aggravate the instability of the goaf and cause the collapse of the surface, which may cause large landslides. Therefore, from the safety point of view, this kind of residual ore is not suitable for the stratified caving method.
The filling mining method is the same as the stratified caving method. It is necessary to treat the mined area to rebuild the mining environment before mining. Compared with the stratified caving method, the filling mining method has the advantage of facilitating the safe management of the stope, protecting the surface from subsidence and reducing The waste rock discharges the surface to the environment; the disadvantage is that the production capacity is relatively small and the cost is relatively high.
Comparison of 2.23 filling methods
2.2.1 Downward layered cementation filling method
The downward stratified cementation filling method works under the roof of the integral cemented filling body (false roof), and is particularly suitable for mining of ore with high ore value, loose rock of the ore and no ground collapse. When the ore is extremely unstable, the overall stable roof provides safe working conditions. The false top is supported by the strength of the cement filling itself and the friction with the surrounding rock. If the existing goaf is not treated before mining, the false roof is not stable at the boundary of the gob and cannot be stabilized. If the goaf is pre-backfilled, it can pass through the goaf during the recovery, so that the false top passes through the goaf to form a whole, to ensure the strength of the false top, and the backfill acts as a working platform for the false top. . Therefore, when using the lower layered cementation filling method, the gob needs to be backfilled in advance. For the mine, due to the current production task, it is not possible to completely treat the mined area and then recover the part of the residual ore. It is not safe to use the mining method. Secondly, the mining method costs more than the upward approach. high.
The advantages of the method: the direction, position and quantity of the approach can be adjusted according to the geological and mineral deposit changes, and the flexibility is large; according to the filling condition, the upper stage and the surface can be deformed or less deformed. Disadvantages: The process is more complicated, the filling cost is higher, and the yield per unit area of ​​the nugget is lower.
2.2.2 Comparison of the upward approach filling method and the box bracket filling method

The mining work of the upward approach filling method is carried out in the approach, the exposed area is small, and the approach only requires a small amount of support, which is suitable for the mining of unstable ore bodies. The box bracket filling method is carried out under the protection of the frame bracket, and the exposed area is smaller, which is suitable for the mining of extremely unstable ore bodies. However, the box bracket filling method has a smaller production capacity than the upward approach filling method, and the labor intensity of the worker is large and the mining cost is high.
Applicable evaluation of 2.2.34 mining schemes for Fukong Mine
(1) Stratified caving method: Because it is not conducive to surface protection, and the mining process requires the use of a large amount of wood, it may cause spontaneous combustion. Although it is technically reliable, it is not reliable in safety and should not be used.
(2) Downward cementing filling mining method: Although it is technically feasible and can effectively control surface settlement, the production cost is high, and the mine has not yet formed a filling system, and the upper residual ore situation is currently unclear, which is not conducive to edge mining. Exploring, therefore, is not suitable for use at present, but this mining method can also be considered after the formation of the mine filling system.
(3) Upward approach filling mining method: This method can effectively control surface settlement, the production efficiency is higher than the box bracket filling method, the production cost is lower than the box bracket filling method, but the ore is allowed to have a certain exposed area, for instability For the residual mines within the scope, it is recommended to use the upward approach mining method for mining.
(4) Box bracket filling method: This method can effectively control the surface settlement, and it can ensure the safety in the recovery process for the extremely unstable type of residual ore.
The mining of the Fukong Mine shall be carried out after the reconstruction of the mining environment in the goaf. According to the current mining conditions, it is recommended to use the box bracket filling method for the extremely unstable residual mine; for the residual mine within the unstable range, it is recommended to use The upper approach is filled with mining method mining. After the management of the transport filling system is formed, it may be considered to use the downward cementation filling mining method to recover the extremely unstable residual ore.
2.3 Economic rationality research
Taking the standard stope (40m×5m×20m) as an example, the main technical and economic comparisons were made between the two methods of the upward approach filling method and the box bracket filling method. According to the mining engineering cost, filling cost, mining cost, and workshop cost, the mining cost is calculated, and the economic value of the mining stope and the mining cost value are compared and analyzed. The upward approach mining method and the box bracket filling method are used to extract the trough. Mines can achieve better economic benefits.
3 conclusions
(1) By mining the trough and other types of residual ore, the mine resources can be maximized and utilized, and the mine can obtain certain economic benefits to make up for the cost of rebuilding the mining environment.
(2) The filling method can create a good mining environment for the recovery of residual ore and downward extension mining, and remove safety hazards such as roof collapse and mining area collapse to ensure the safety of mining operations.
(3) By comparing the safety feasibility, technical reliability and economic rationality of various mining methods, the upper-direction filling method and the frame-supporting filling method are adopted for the residual ore and extremely unstable residual ore in the unstable range. Mining.
references:
[1] Zheng Huaichang, Li Ming. Risk of underground goaf and its analysis [J]. Mine Pressure and Roof Management, 2005 (04): 127-129.
[2] Zhu Heling. Research on stability and reliability of reconstructed artificial structures based on mining environment [D]. Changsha: Central South University, 2008.
[3] Chen Qingfa, Zhou Keping, Gu Desheng, et al. Collaborative utilization mechanism of goaf [J]. Journal of Central South University (Natural Science Edition), 2012 (03): 1080-1086.
[4] Chen Qingfa, Zhou Keping, Goodyear. Collaborative mining and collaborative use of goaf [J]. China Mining, 2011 (12): 77-80, 102.
[5] Chen Qingfa, Zhou Keping, Hu Jianhua, et al. Collaborative research on mining and empty area treatment of broken ore section [J]. Journal of Central South University (Natural Science Edition), 2010 (02): 728-735.
[6] Li Aibing, Zhou Aimin, Yin Yanbo, et al. Study on the characteristics caving Shizhuyuan group metal deposit empty zone conditions [J]. Journal of Rock Mechanics and Engineering, 2008(11): 2234-2243.
[7] Qian Haihong, Deng Xiuyan, Xu Rongjun. Application practice of high step caving method in treating composite goaf [J]. Engineering Blasting, 2007 (03): 42-44.
[8] Chen Xibing. Discussion on the treatment method of suspended roof in goaf in stratified caving method of kaolin mine [J]. Non-metallic mines, 2009 (S1): 27-28.

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