Application study of post-filling mining method for high-stage deep-hole collapse
With the increasingly tight resource situation, the gradual improvement of environmental protection policies and the continuous development of filling processes and materials, more and more mining enterprises are in order to ensure the safe production environment underground, maintain the ecological balance of the surface, and avoid the occurrence of mining subsidence. Gradually began to pay attention to the test and application of protective mining methods, especially the practice of “three down†safe and efficient mining technology for steeply inclined thick ore bodies. Because such ore bodies usually have a wide range of applications and a large overall thickness, the recovery will inevitably lead to an increase in the area of ​​the underground goaf and the treatment pressure of the tailings. If not properly handled in time, it is easy to cause the overburden of the empty area to fall (even The surface subsidence) and the tailings storage capacity are becoming increasingly tight. At the same time, most of the mining and cutting projects in the two-step mining process need to be arranged in the filling body. The surrounding rock of the roadway is poor in stability, and the maintenance is difficult in the later stage, and the loss and the depletion rate are high. Seriously affect the production of the lower middle section, which will bring significant safety hazards and loss of benefits to the normal production of the mine.
Based on previous studies, Anhui Jinan Iron Mines Limited mine grass floor area of underground mining engineering background, to carry out industrial tests, rational arrangement for Heavy steeply inclined ore stope, optimization of process parameters and equipment Supporting a more systematic study, in order to provide a certain theoretical basis and technical reference for the realization of safe and efficient mining of similar ore bodies.
1 Project Overview
Anhui Jinan Mining Co., Ltd. Caolou Iron Mine was put into operation in 2007. The current production capacity is 3 million t/a ore, the working system is 330 d/a, 3 shifts/d, 8 h/shift, and the mining area is divided into three parts. 3 mining areas, of which the main well mining area is located between 8 and 19 lines, using down-diameter large-diameter deep-hole empty field (VCR) and post-filling mining method, non-track mining and orbital transportation, and the production capacity of mining area is 2 million ore. t/a; Nancai District is located between 8~24 lines. It adopts shallow hole mining and mining method, flat bottom structure, loader and dump truck mining. The production capacity of mining area is 300,000 t/a ore; In the line between 19 and 23, the mining method of stage mining is adopted, the flat bottom structure is used, and the loader is equipped with dump trucks for mining. The production capacity of the mining area is 700,000 t/a.
1.1 Hydrogeological conditions of the ore body in the main well mining area
South of the 29# mine, north of the 0 line, the ore body is thick, the ore body is layered or lenticular, and the occurrence is consistent with the surrounding rock, and the inclination angle is about 50°. The ore body has frequent branching on the 0~7 line, and the main ore body is about 60~100 m thick. There are I ore bodies at about 8m on the main ore body, distributed in the 3~7 line, the thickest at the 7th line, about 14m at the -250m elevation, and thinner at the 3rd line. The ore grade is about 30%.
The engineering geological conditions are simple. Ore top, bottom slate stone mainly biotite gneiss plagioclase amphibolite, gneiss. The quality of the ore is medium, the rock mass is weak and fragmented, and the stability is poor.
The hydrogeology is simple, and the underground water is small. However, in the upper part of the ore body, there are weathering layers and Quaternary topsoil (localized sand layer). Therefore, it is necessary to protect the water-repellent layer in the upper part of the ore body and control the water-conducting fissures.
1.2 Status of mining in the main well mining area
The main mining area is currently mining the ore body between -170~-230 m in the middle section, the vertical ore body of the ore block is arranged, the ore compartment is divided into the ore room and the pillar, and the large-diameter deep-hole empty field is used to fill the mining method. Steps are taken back, the bottom structure is a flat bottom trench, and the scraper is out of the way. During the actual production process, the mine exit roadway and part of the ore mining road are located in the filling room of the mine. Because the strength of the filling body is larger than the strength of the rock mass, combined with the impact of blasting vibration, the roadway has a serious phenomenon of collapse and collapse, and the maintenance cost and The labor intensity has increased significantly. At the same time, if the original mining method continues to use the original mining method in the middle of the -230~290m middle ore mining, it is necessary to increase the level of the ore-free ore and rock drilling level, and the horizontal transportation column and the trackless ore level. The bottom structure triangular pillar accounts for about 1/3 of the corresponding middle section of the ore, and the recovery of this part of the ore is difficult, and the above-mentioned pillar recovery problem still exists. Therefore, it is necessary to improve the stope structure of the deep-hole collapse ore-filling mining method in the active stage to solve the difficulty of mining pillar mining.
2 Optimization of structural parameters of test stope
According to the mining technical conditions and engineering status of the Caolou iron ore mine, the surface of the mine section is villages and farmland, and the surface is not allowed to collapse; the upper part of the ore body is a broken weathering zone, and the water permeability is strong. The damage and collapse should be avoided, so the filling is still used. Mining law for mining. Combining the current situation of ore mining and deep development engineering layout, in order to meet the normal connection of the lower middle section, ensure the safety of mining pillars, and save the mining and cutting engineering volume, and improve the ore recovery rate, the -170 ~-230m middle section and -230~ The middle section of -290m, the middle section of -290~-350 and the middle section of -350~-410m are considered as a whole, and the high-stage deep hole collapse ore filling after "upward mining, combined rock drilling and concentrated mining" is innovatively proposed. Mining law.
2.1 stope structure parameters
(1) Reducing the bottom structure of a middle section and part of the roadway engineering quantity, saving part of the mining time, and recovering the lost ore amount of the corresponding stop top column and bottom triangular pillar, and the ore recovery rate is improved;
(2) The width of the mine house and pillar in the ore block is adjusted to 18 m, and the unilateral ore is discharged. The bottom structure of the stope is always placed in the undisturbed ore body, which increases the safety of the pillar recovery and reduces the mining loss rate. The ore depletion rate, but the height of the filling body on both sides of the pillar is about 105 m (the sum of the heights of the two middle sections minus the height of the bottom column is 15 m). Therefore, the strength of the filling body of the mine is higher and the filling cost is also increased. In addition, there are more residual ore in the lower part of the ore body, which is not conducive to ore mining.
2. 2 middle section mining order
Due to the poor stability of the roadway in the middle section of -230m, the mining has not been carried out. Considering that the mid-section of the ore block is exactly the same as the -230m middle section, the corresponding section of the -290~- 410 m is completed and filled. After consolidation, the mining work of the middle section of -230 m and -290 m can be carried out. The part of the pillar is also combined with the high-stage deep-hole collapse ore-filling mining method for double-middle section mining, of which -170 m and -230 m are rock drilling levels, -290 m is the level of ore discharge, and the ore that is blasted is discharged to - The 410 m horizontal loading truck is transported out, and a filling is carried out after the end of the mining. The 60 m of the lower part of the empty area is filled with cement with full tailings, and the upper part of 60 m is filled with low-grade tailings. After the above-mentioned mining and filling work is completed, the surrounding rock of the -290 m middle section of the mine is filled, combined with its own mechanical properties and carrying capacity, the alternative mining methods are staged deep hole collapse and post-filling mining method, The segmental empty field is filled with mining method and upward horizontal layered filling mining method. Stage deep hole collapse mine after filling mining method : in the -290 m middle section of the pillar filling construction of the mining roadway, construction of the mine chamber rock chamber at -245m level, leaving 15 m above the level as the top pillar of the mine, The rock drilling chamber is drilled into the deep hole. Subsection empty field post-filling mining method : 8 m of the top of the mine is left as the top column. The following sections are -251, -264, -277 m and -290 m, with a total height of 13 m. In the lower part of the ore body, a sectional contact roadway is arranged. The medium-deep hole drilling machine is used for section rock drilling, section or stage blasting. The mine is mined in the lower part of the stope, and the bottom structure of the ore is filled in the same stage. After the end of the mining stop, the filling is completed in all stages. Upward horizontal stratified filling mining method : the stage height is 60 m, the top column height is 4 m, divided into 4 sections according to the height of 15 m, and the length is the thickness of the ore body and the width is 15 m.
3 on-site industrial test
In January 2011, the main mining area of ​​Caolou Iron Mine started the high-stage deep-hole collapse ore-filling mining test and application research work. During the period, the daily mining volume and the working efficiency of the scraper at a level of 395 m were carried out. Statistics, the sunrise ore observation curve is shown in Figure 2.
It can be seen from Fig. 2 that the actual production capacity of the middle section is 7135. 6 t/d during the double-middle section combined mining (-290~-410 m) with high-stage deep-hole collapse ore filling method. For the 469. 24 t/set class, the average rig efficiency of the down-the-hole rig is 38.02 m/set/shift, and the labor productivity of the miners is 4424.27 t/person. Combined with the above observations, it can be seen that the test plan can well meet the production scale requirements of the mining area.
It can be seen from Table 1 that during the application of the high-stage deep-hole collapse ore filling method in Caolou Iron Mine, the technical indicators are superior to the design indicators, which ensure the safe and efficient recovery of mineral resources .
4 Conclusion
(1) In order to ensure the safe and efficient recovery of the two-step pillar in the initial stage of mine mining, the middle pillar of -170~-230m and the middle section of -230~-290m, the middle section of -290~-350m and the middle section of -350~-410m As a whole consideration, the high-stage deep-hole collapse ore-filled rice ore method of “upward mining, joint rock drilling, and concentrated ore mining†was innovatively proposed.
(2) In order to reduce the adverse impact of blasting vibration on the stability of the mining roadway during the two-step mining process of the ore block, combined with the occurrence of the ore body and the status quo of the mine mining, the structural parameters of the stope are optimized, and the width of the ore block is adjusted to 36. m, in which the mining room and the pillar are 18 m each.
(3) The results of on-site industrial tests show that the high-stage deep-hole collapse ore filling method improves the mechanization level of the stope and the production capacity of the stope, while effectively saving the amount of roadway engineering, reducing the loss of minerals and reducing the labor intensity of workers ; The joint support design scheme has good control effect on the surrounding rock of the roadway, meets the requirements of underground safety production, and has obvious economic and social benefits.
In summary, the high-stage deep-hole collapse ore filling mining method has been successfully applied in Caolou Iron Mine, accumulating the practical experience of safe and efficient mining of thick and steep inclined ore bodies, enriching the research results of optimization and improvement of filling mining method. And it has certain theoretical guidance and practical reference for underground engineering problems under similar conditions.references:
[1] Xie Shijun. Underground mining of metal deposits [M]. Beijing : Metallurgical Industry Press, 1995.
[2] Cai Meifeng. Rock Mechanics and Engineering [M]. Beijing : Science Press, 2002.
[3] Zhou Weijun. Higher Rock Mechanics [M]. Beijing : Water Power Press, 1990.
[4] to learn Fu stability of the underground engineering analysis [M] Beijing: Coal Industry Press, 1983.
[5] Xu Yongzhen. Mining Science [M]. Xuzhou: China University of Mining and Technology Press, 2003.
About the author: Xie Yingxiang (1970-), male, Shandong Weifang, engineer, mainly engaged in mining professional and technical work, Email:.
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