1 mining method
I# copper ore belt adopts point-column upward stratified filling method [1], stage height 100m, section height 20m, layer height 4m, ore length 50m, ore width is ore body horizontal thickness, ore height According to the height of one section, the stopway, the returning wind uphill, etc. are set at a spacing of 300m.
1.1 Stope layout and structural parameters
The stope is arranged perpendicular to the direction of the ore body. The length of the section is 300m. Each section is equipped with a slipper and a return wind uphill. The length of the ore block is 50m, the width is the horizontal thickness of the ore body, the length of the mine is 50m, the width is the horizontal thickness of the ore body, the width of the column is 4m, the size of the column is 6m×6m, the spacing is 18m, and the size of the back-up wind is 2m×2m. The first mining layer is 5m high, and the height of each layer is 4m. The first layer is filled with cement for 3.3m, the remaining layer is filled with graded tailings of 3.5m, the cemented filling is 0.5m, and the height of the empty roof is 1. 7m. The main mining indicators are shown in Table 1.
1.2 Cutting and cutting project layout and construction sequence
The mining and cutting project adopts the mining mode of the outer pulse road and the outer roadway. The first step is to dig the segmental contact road to the ore body every 20m from the gentle slope of the slope, and then 50m away from the ore body. Along the ore body, the sublevel mining line is driven, and the sub-section of the corresponding stope in the section roadway is used to dig into the sub-field. The first layer of contact roads is driven by ≤15% downhill, and the above layered contact roads are carried out by topping and bottoming, and the maximum climbing is not more than 10°. In the end of each stopway, the most top-level ore body is arranged on the upper plate to return to the wind and up the mountain, and communicate with the upper middle section.
1.3 recovery work
The mining work starts from the picking joint road and the cutting fork fork picking. After picking up the level of the layered roof, the working face is opened to the two gangs to form the working face, and the mining is carried out by the mining tunnel to the two wings. From the position of the column to the stope, after the two adjacent approaches are pushed into place, the top stay column is removed from the two wings of the stope. In the stope, the mining sequence is carried out by the mining joint road to the two side columns, the mining line from the two sides to the backtracking, and the mining order of the first plate and the lower plate, until the design boundary is obtained, and the layered mining work is completed.
(1) Rock drilling. The single-arm trolley Boomer281 rock is used, the hole depth is 3.5m, the blasthole row spacing is 0.7-0.9m, the hole spacing is 0.8-1.0m, and the blasthole spacing of the top plate light-blasting layer is 0.7-0.8m. Light burst layer thickness 0.6~
0.8m, the entire approach to the blasthole is finished.
(2) Blasting. The 35mm rock emulsion explosive is selected, the millisecond non-conducting detonator is detonated, and the row is subjected to millisecond blasting [2]. The interval time is 25~50ms. The detonation layer is detonated by the detonating cord and the subsequent bursting is performed.
(3) Mining. After being transported to the chute by a scraper or transport vehicle, it is lowered to a transport level of 380m.
(4) Ventilation lines in the stope. Fresh air flow→segment trunk line→recovery joint road→seed field→stained wind→returning wind uphill→upper section mining road→upper section trunk→return air system.
1.4 stope filling
The first layer is filled with 12mm diameter steel bars with a spacing of 200mm. The first layer is filled with a height of 3.3m. It is filled with tailings cement and the ratio of sand to sand is 1:4. After the stratified mining, the glue should be mixed with the end of the sand. The lower layer is 3.5m high and the full tail sand is filled. The final sand is cemented at the last 0.5m of each layer. The ratio of sand to sand is 1:6, and each layer is filled. Reserve 1.7m empty top. The stope drainage is discharged into the underground sewage treatment station through the internal drainage hole or the lower drainage hole of the stope to the underground sewage treatment station [3]. The principle of two-layer filling and draining in the first section of the stope is shown in Figure 1. The principle of filling and draining in the second-stage stop is shown in Figure 2.
1.5 top board management
During the mining operation, personnel equipment is directly exposed to the goaf, and roof management is more critical. In addition to the top layer smooth blasting method, in the actual production, different methods of roof protection should be adopted according to the grading of the roof to confirm the safety of the roof. After the personnel equipment can enter.
2 problems and countermeasures
The deep part of I# copper ore belt is located in the lower part of II1# main ore body, and the lower part is separated from II1# main ore body by more than 3 to 10 m. With the continuous decrease of the mining depth of II1# main ore body, the stress concentration and ground pressure will be more The more obvious it is, the deeper ore of the I# copper ore belt is layered, and the joints and fissures are relatively developed. In the production process, it is affected by blasting vibration and weathering, and the stope occurs when it occurs. A big security risk.
In this regard, in the actual production process, the structural parameters of the stope are optimized, the point column size is 4.0m × (4 ~ 5.0) m, up to the roof of the ore body, the spacing between the point and column is 11m × 10m. After the optimization of the stope structure parameters, the actual recovery rate is 74.6%, and the depletion rate is 12.49%. The optimized stope structure is shown in Figure 3.
Due to the excessive fineness of the tailing sand and the large amount of mud, the tailing sand has a slow settling velocity in the vertical silo, the utilization of the tailings is low, the dewatering of the stope is difficult, and the strength of the filling body cannot meet the design and recovery requirements, resulting in I. #铜矿 with deep filling (Fig. 4) lags, insufficient reserves, affecting the normal and continuous mining production. In this regard, according to the actual situation of the production and construction of the Dahongshan Iron Mine, when the filling capacity fails to meet the production demand, the underground mining and cutting stone will be transported to the deep mined area of ​​the I# copper ore belt for filling.
The deep ore of the I# copper ore belt is layered, the joint fissures are developed, and the stability is poor. Under the influence of weathering, blasting vibration and ground pressure, some of the roofs of the stope are prone to large-scale collapse, and the stope only Can be abandoned, resulting in low ore recovery rate. In this regard, in advance of ensuring safety, from the construction of the safety channel of the adjacent panel to the upper plate of the ore body, the mining plate is taken down from the upper plate to increase the recovery rate. The comparison of 5054 panel mining optimization before and after is shown in Figure 5.
The deep mining area of ​​I# copper ore belt adopts the point-column type upward stratified filling mining method. According to the requirements of the third-level ore mining and charging and charging relationship, the upper section of the mining road must be completed before the mining of the lower section ore. Advance construction on the section of the mining road, resulting in the upper and lower sections of the joints of the overlapping sections of the mining area is too high, the roof is difficult to manage, coupled with the deep stability of the I# copper ore deep rock, there are safety hazards in mining. To this end, it is proposed to eliminate the safety hazards in mining in high-altitude areas by alternately filling adjacent panels and appropriately increasing the engineering. The comparison of the 4062 panel 5 layer mining design before and after optimization is shown in Figure 6.
3 Conclusion
In the mining project of I# copper ore belt, Dahongshan Iron Mine has optimized the point-column upward stratified filling method according to the actual situation of the ore body and the actual production, in view of the problems in the mining process. The 1.5 million t/a project of the copper mine belt went smoothly, meeting the economic and technical requirements of the original design.
references
[1] Wang Wei, Wang Jianzhong, Zhang Shengxiang. Cangshan iron ore double-layer ore body mining balance management [J]. Modern Mining, 2015 (6): 53-54.
[2] Niu Kui. Application of hole-by-hole differential blasting technology in the descending section of Hegou tunnel[J]. Modern Mining, 2015 (1): 60-61.
[3] Liu Tongyou. Filling mining technology and application [M]. Beijing: Metallurgy Industry Press, 2001.
Article source: "Modern Mines"; 2016.3;
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