Green Mountain copper copper iron ore deposit is located in southeastern Hubei Province, the Yangtze River iron ore copper metallogenic belt west, is a former Sinian the basement, from Sinian to three Triassic of depression zone, developed a set of sea The stable deposition of phase and land phase, followed by the Indosinian and Yanshan multi-cycle movement, formed a complex cover layer fold belt. The ore body is lenticular or layered on the section, which mainly exists in the contact zone between magmatic rock and marble , and then is placed between the marbles in the contact zone, and the contact structure is the main ore-controlling structure of the mining area [1]. The overall orientation of the ore body is southeast, the dip angle is 60°～80°, the rock joint fissures are developed, and it is moderately stable. The surrounding rocks of the top and bottom plates are mainly skarn, marble, plagioclase , etc. The lithology is complex and moderately stable~ Steady [2]. At present, the main back mining III#, IV# ore body, -305, -365, -425, -485m4 middle section. The III# ore body is about 600m long and the ore body is 7-80m thick. The IV# ore body is about 1400m long and 3~5m thick.
As the depth of mining continues to increase, the ore body becomes thinner. At the same time, the original rock stress inside the rock increases. In the absence of mining engineering disturbances, the rock mass is in an original equilibrium state. The excavation of underground roadway or stope breaks the original equilibrium state of the stratum, resulting in the release of ground stress, which causes the deformation of the rock mass and the displacement to the free surface, so that the stress of the surrounding rock is redistributed. Excessive displacement and stress concentration of the surrounding rock will lead to local or overall instability and destruction of the surrounding rock, and the stability is getting worse.
The Tonglushan Mine originally used the VCR mining method. As the ore body became smaller, the mining depth increased, the ore was depleted, the stability of the side and the roof of the stope deteriorated. Later, the common method was used to fill the mining method horizontally. The high strength and low production efficiency can not meet the needs of safe production [3], and it is urgent to optimize the existing mining methods.
1 mining method selection
In order to ensure safe and efficient production downhole, Tonglushan Mine and Central South University cooperated and decided to change the existing mining methods.
Mining method selection principle [4]:
(1) Have safe and good working conditions.
(2) Fully, efficient and comprehensive utilization of underground mineral resources.
(3) It has large production capacity and high production efficiency.
(4) Low mining cost, high economic benefit, and little damage to the ecological environment.
(5) It has versatility.
According to the above principles, Central South University combined with the production needs of Tonglushan Mine and the conditions of underground operations to determine the use of segmented empty field å—£ post-fill mining method. The mining method has high mechanization degree, low artificial strength, high production efficiency, small amount of mining and cutting engineering, small ore depletion, and high safety factor.
2 mining process
2.1 stope structure parameters
The vertical ore body of the stope is arranged. The length of the ore block is the thickness of the ore body. The width of the ore block is 10m, 60m, the height of the top column is 12m, and the height of the bottom column is 8m. It is divided into 4 layers and the layer is 13m high. A ventilation cable well is placed in the borehole of the ore body, and the size is 1.6m×1.6m. The filling method of the segmented empty field is shown in Figure 1.
2.2 Cutting and cutting engineering layout
2.2.1 Rock drilling roadway
Each layered rock drilling roadway is arranged on the upper part of the vein ore body, and the depth of the row holes tends to be averaged in order to drill, and the rocking is convenient to fall, and the rocking roadway is usually arranged in the middle of the stope. In order to meet the entry and exit of rock drilling, charging and mining equipment, the roadway size is 4.0m×3.5m. During the construction process, the mining boundary is used as the operating limit and the boundary of the mining yard shall not be exceeded.
2.2.2 cutting slot
A 2m×2m cutting cross-section is constructed at the end of each layered rock-drilling roadway, and then a 2m×2m patio is constructed by using a vertical medium-deep hole blasting method, and the patio is used as a free surface to expand the two control lines of the stope. Help, finally forming a cutting groove of 10m wide and 12m high, providing sufficient free surface and compensation space for subsequent continuous blasting.
2.2.3 bottom mining structure
In order to ensure the mining efficiency of the stope, three outflow paths are arranged along the direction of the stope, and the section size is 3m×2.8m.
2.3 mining operations
The medium and deep hole section rock drilling equipment mainly includes YZ-90 drilling rig , Atlas K41 drilling rig , and Sandvik DL331 drilling rig. In order to improve the drilling efficiency, choose the Sandvik DL331 drilling rig.
The vertical parallel hole is drilled in the cutting groove area, and the upward direction fan-shaped parallel blast hole is drilled in the sectioned rock drilling roadway. The diameter of the drilling hole is 76mm, the row spacing of the cutting slot is 1.2m, and the normal hole row spacing is 1.5~. 2m, the hole bottom distance is 2 ~ 2.5m, the side hole angle is 15 °, the charge factor is 0.8.
First of all, it is necessary to complete the blasting and falling mine of the cutting well. After one well is formed, the two sides are expanded and blasted in the direction of the central gutter to form a cutting groove. The normal area blasts 3 to 5 rows at a time, blasts into the empty area of ​​the cutting slot, and then retreats in turn. With gold can JNJR-100 type charge carriage charge, non-electric blasting detonating tube rows millisecond hole bottom, millisecond interval of 25ms.
During the recovery process of the stope, the drilling angle and the partial slope should be controlled. When the fracture zone is encountered, the drilling speed should be controlled; the roof of the stope should be formed along the ore body to form a micro-arch; the roof, mining height and ore body boundary should be strictly controlled. The mining is strictly carried out according to the calibration of geological survey personnel to control the loss rate and the depletion rate. The design requirements must be met after the stop mining is completed.
2.4 Ore handling
A combination of mechanical handling and gravity handling is used to arrange an extra-pulse funnel every 30m. After the end of the mining blasting, part of the ore is scraped from each section of the rock drilling roadway by WJD-2 electric scraper, and the remaining ore is left to be mined in the lower section.
After a section of mining is completed, the next section is taken back. After the last section is recovered, the ore left in the empty field is discharged by remote-controlled scraper, and the shoveled ore is discharged to the surrounding chute and transported in a unified stage. It is best not to carry out secondary blasting in the mining site to prevent damage to the bottom mining structure.
2.5 ventilation
The local fan ventilation is adopted. The fresh air flow enters the mining roadway or the sectioned rock drilling roadway from the middle section Shimen roadway or the mining slope road. After flushing the working face, the sewage wind is from the section roadway or the stope empty area and the upper middle section return air passage to The wind well drains the surface.
2.6 filling
After the end of the mining site, the goaf is filled once. Set up the filter water pipe in the stope before filling, and do the work of blocking the dam. The filling material is full tailings and curing agent. The one-step mining room is filled with full tailings cementing, the ratio of sand to sand is 1:13; the filling of two-step mining column is filled with full tailings, cemented paving, paving thickness 0.5m, ash The sand ratio is 1:6.
3 technical and economic analysis
Through the field test of the segmentation empty field and the post-filling method, it is found that the method has a larger production capacity than the original mining method and the ore loss is less. See Table 1 for details.
4 Conclusion
The segmented empty field post-filling method has been successful in the Tonglushan Mine, effectively improving the current situation of insufficient production efficiency, improving the mechanization of production and labor productivity, reducing the quota and labor intensity, and reducing the amount of mining and ore. Depletion loss, safe operation and low cost. In the process of deepening the deep mining of Tonglushan Mine, it is necessary to continuously summarize the experience according to the site conditions, optimize the design scheme and process parameters, improve the management level and equipment efficiency, and further promote the application of the mining method in underground mines.
references
[1] Cheng Yong, Dai Honghui, Zhou Keli, et al. Application of mechanized upper meso-depth and high-layer stratified filling method in the Tonglushan Mine [J]. Mining technology. 2015, 15(6): 3-5.
[2] Xiong Guoxiong, Zhao Xiongwen, Lu Bo, et al. Application of upward horizontal approach filling method in Tonglushan Mine [J]. Modern Mining, 2012 (11): 4-6.
[3] Zhou Keli, Huang Xian, Wang Yao, et al. High-efficiency mining method optimization scheme in the test of Tonglushan Mine [J]. Modern Mining, 2010 (9): 69-71.
[4] Xue Xilong. Study tailing filling techniques apricot high concentration of phosphorus ore [D]. Changsha: Central South University, 2012.
Article source: "Modern Mining"; 2016.10
Author: Xiongguo Xiong; Daye Nonferrous Metals Co., Ltd. Tonglushan copper ore;
Copyright:
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