A phosphorus miners mining thickness 3 ~ 8m, average 6m, ore angle 20 ° ~ 50 °, the inclined orebody genus thick, performed using Bolt and mining sublevel top field method [1-2]. Affected by geological conditions, a steeply inclined ore body with a length of about 600 m is formed at both ends of the main mining body, and the inclination angle of the ore body is 70° on average. For the steeply inclined ore body, the current domestic mining mainly uses shallow hole retention method [3-4], stratified caving method, and upward horizontal stratification filling method [5]. This study is aimed at the mining technical conditions of medium-thick steep ore bodies [6], and uses the in-pulse-pulmonary combined mining and post-carrying filling method to extract, in order to greatly increase the production capacity of the panel.
1 mining technical conditions
A medium-thick and steeply inclined ore body of a phosphate rock is present at both ends of the main mining body with an inclination of 60° to 85° and an average thickness of about 5 m. The ore body is relatively broken, the stability coefficient f=6～7, and the artificial roof of the ore body has a thickness of 1~2m, and the artificial false top has low strength and is easy to fall. The ore body belongs to a single inclined stratum, the stratum tends to be 105°-160°, the dip angle is 20°-35°, the upper part of the ore body is dolomite , and the lower plate is sandstone or shale . The geological structure of the ore body is complex, there are two longitudinal faults, joint fissures are developed, and rock drilling and blasting performance is better.
2 mining methods
According to the mining experience at home and abroad and the mining technical conditions of the medium-thick and steeply inclined ore body of the phosphate rock, based on the existing mechanical equipment, production capacity and labor level of the mine, the in-pulse-pulmonary external mining and post-filling method is adopted. Mining (Figure 1).

2.1 Summary of the program

The length of a certain section of the mine is 300-500m and the height is 50m. The panel is divided into several ore blocks along the strike. The length of the ore block is 30-40 m. Each quarry is divided into mine pillars. The length of the mine pillars is 15-20 m. The nuggets are harvested in two steps, first mining and then mining. The panel is divided into three sections from top to bottom, each section is 14m high and 109 pillars are 8m high. An extra-pulse ramp is used between the segments. During the mining operation, a cutting patio is drilled at the end of the stope to ensure a through-flow between the stope and each segment. The DL330 rock drilling rig is used to drill the upper fan-shaped middle hole in the section rock drilling roadway, and the cutting patio is used as a free surface blasting, and the whole section is opened. After pulling open, the same row of the same row, the same row of each segment plus the detonating tube parallel network one-time detonation, one blast each time. The caving of the ore is run by the EST1030 electric scraper through the stage of the outflow of the mine, the middle section of the transport and the smoothing of the well. After the mining of the entire mine or pillar is completed, the phosphate or gypsum cement is filled into the mine or pillar. The cement filling is carried out in two steps. The high-strength cemented filling body is used for filling, and the filling height is 8 m. After the high-strength cementing filling is completed for 3 to 5 days, the low-strength cemented filling body is used to fill the entire stope.
2.2 mining engineering layout
All the mining projects are arranged on the upper part of the ore body. The mining engineering mainly includes the middle section transportation lane, the panel slope road, the section transportation lane, the section contact roadway, the pulse rock roadway, the cutting mountain, and the stage mining. Lane and so on. Firstly, the middle section of the road is transported into the middle section of the road, and then the slope of the section is drilled. Then, the sectioned transport and the sectioned vein rock roadway are drilled in each section, and the sectional transport and sectional rock drill are segmented. The roadway is connected by a section to the crossroad. The end of the sectioned rock drilling roadway is digged into the stope to cut the ventilation patio, and the cutting ventilation patio is sectioned up and down. At the bottom of the mining stope, the mining roadway is drilled every 8m. If the average true thickness of the ore body is calculated according to 4.5m, the height of the middle section is 50m, the density of the ore body is 2.78g/cm3, the length of the panel is 500m, and the amount of ore in one panel is 312750t. According to Table 1, the cutting ratio is 220.9m3/kt. .

2.3 mining process
(1) Rock drilling. The DL330-5 rock drilling rig was used to drill the upper fan-shaped medium-deep hole in the intra-pulmonary rock roadway with a hole diameter of 60 mm. Before the mining, in order to form a free surface, the full section of the cutting mountain should be pulled apart. The row spacing of the slotted holes is 1.2-1.4 m, and the hole bottom distance is 2.0 m. After the trough is completed, in order to control the bursting degree after blasting, according to the optimization test results of the deep hole blasting parameters in the phosphate rock, it is determined that the blast hole row spacing is 1.6 m and the hole bottom distance is 1.8 m.
(2) Charge blasting. The manual charging method is adopted, the explosive is selected as the emulsified volume explosive, and the detonator is selected as the non-conducting squib detonator. The same row and the same segment are used, and each segment is simultaneously detonated in parallel with the same row. The end of the blasthole is sealed with custom gun mud, the sealing length is 0.8m, and the explosive consumption is 0.2kg/t.
(3) Ventilation of the stope. The fresh air flow enters the stope by the ramp road, the lower section transporting the alley, the lower section of the contact cross section and the lower section of the rock drilling roadway. After cleaning the working surface, the dirty wind is cut by the upper mountain, the upper section of the rock drilling roadway and the upper part. The section connects the lane to the return wind lane.
(4) Support. Due to the low strength of the roof of the phosphate ore body, the joint fissures are developed, and the artificial false roof is locally present, so the roof of the rock drilling roadway needs to be supported. The intra-pulse rock drilling roadway is supported by bolts and anchor nets, and the top column is supported by prestressed anchor cables.
(5) Mining. The ore is used for flat-bottom mining. The ore is transported to the out-of-pulse chute through sectioned rock drilling roadway, sectional communication cross-drainage, and sectioned transport flat roadway. The run-through ore is transported to the surface by motor vehicle.
(6) Filling of the stope. Phosphogypsum cementation filling is carried out after the recovery of the entire stope. In order to ensure the safety of the next stage of recovery, the phosphogypsum with a ratio of 1:1:4 and 1:1:1 is filled in two steps. First, a high-strength cemented filling body with a ratio of 1:1:4 was used for filling, and the filling height was about 8 m. After the high-strength cementation filling is completed for 3 to 5 days, the entire stope is filled with a low-strength cemented filling body with a ratio of 1:1:6.
3 on-site industrial test
According to the mining situation, the industrial test was carried out in the N#4 mine in the middle section of 1080m in the South 4th district (Fig. 2). The height of the test stope stage was 40m. After the upper layer of long anchor cable support is completed, the mining process such as rock drilling, blasting, ventilation, support, mining, filling and so on will be started. After blasting, the blasting block is relatively uniform and the production capacity of the stope is large. The long anchor cable supports the roof to ensure the safety of the workers.

The production capacity and technical and economic indicators obtained through the test are: rock drilling rig rock drilling efficiency 90m/shift; scraper mining efficiency 780t/shift; medium and deep hole blast hole collapsing 4.25t/m Filling station filling capacity 50m3 / h; mining length is 20m, mining capacity is 14011t, mining total cycle period 48d, stop production capacity is 291.9t / d; depletion rate 1%; loss rate 8%; The ratio is 220.9m3/kt; the mining cost (rock drilling, blasting, mining) is 12.15 yuan/t.
4 Conclusion
Taking a phosphate mine as an example, according to the mining technical conditions of the mine's steeply inclined medium-thick ore body, the in-pulse-pulse-external combined mining and post-filling method is used for mining. The test shows that the method has a large amount of mining and mining. It has the advantages of high ratio, small section, large production capacity, high degree of mechanization and low depletion rate. It can optimize the operation process according to the actual situation during mining, improve the recovery efficiency, and has certain promotion and application value.
references
[1] Chen Faji, Long Xiucai. Application of post-pulse mining of medium-deep hole ore deposit in Shaba soil and minerals [J]. Modern Mining, 2011 (5): 62-63.
[2] Xu Yong, Peng Kang. And the application of the post-filling method in the middle section of the empty field stage in deep mining [J]. Modern Mining, 2010 (6): 82-83.
[3] Wang Chenglong, Wang Ying. Application of shallow flat bottom hole Shrinkage Method Dow company two gold mine [J]. Modern Mining, 2015 (6): 210-211.
[4] Song Yi, Zhou Yilong, Jiang Feifei. Application of shallow hole retention method in mining steeply thin to extremely thin veins [J]. Modern Mining, 2015 (6): 32-34.
[5] Peng Fujun, Zhu Tianping, Wang Xunqing. Eligible layered mine mining method to improve the filling level of each Qi copper [J]. Nonferrous Metals: Mine Section, 2012(4): 14-16.
[6] Goodman, Li Xibing. Modern metal deposit mining science and technology [M]. Changsha: Metallurgical Industry Press, 2006.
Article source: Modern Mining, 2011.5
Author: Zhao Jingqing in Chongqing Institute of Coal Science and Industry Group Co., Ltd:

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