Study on Mechanized Approach Filling and Mining Method for Slowly Inclined and Thinner Ore Body Panel

The mining of gently inclined and thin ore bodies has always been recognized as a major technical problem at home and abroad. Due to the gentle inclination of the ore body, the horizontal inclination of the floor of the stope is smaller than the natural angle of repose of the heap. The ore cannot be slid and cannot be concentrated in the bottom structure. The thickness of the ore body is thin, it is not suitable for efficient blasting in the deep hole, and the ore is depleted. The rate is higher; the ore body and surrounding rock are broken, the exposed area is allowed to be small, the safety is poor, the recovery of the pillar is difficult, and the loss of the ore is large [1]. For the recovery of such ore bodies, the comprehensive method of the hydraulic props and the room and column method [2-3], the pseudo-inclined single tailings cementing filling method [4], and the controlled blasting in the stope are adopted. Technical measures [5]. Although the above mining methods have improved the safety of the stope to a certain extent and adapted to the ore body production, the production capacity is lower and the labor intensity is greater.
Occurrence wherein the thin broken ore body is inclined according to an exemplary gradual herein a silver ore Guangdong, research mining method, formation technique reliable, economically feasible technical solution mining methods, fragmentation is gently inclined narrow orebody safe efficient extraction reference.
1 mining technical conditions
The mining area is located at the junction of Foshan City and Zhaoqing City, Guangdong Province, close to the city, close to the Xijiang River, surrounded by dense villages, university towns, etc., and has high environmental protection requirements. The deposit is a medium-low temperature hydrothermal concealed silver deposit, and the ore body is layered and produced in parallel. The main ore body I ore body is located in the Fx1 slip-off fault zone between the Upper Triassic Xiaoping Formation and the Lower Carboniferous interface. The ore-bearing rocks are silicified rocks, silicified breccia, and silicified limestone. The structural plane is mainly grade II, and the rock mass structure type is layered structure (II1) and layered fragmentation structure (III2). The rock is a polygonal block.
The natural compressive strength of rock is 24.40～115.50MPa, and the average value is 62.05MPa. The engineering stability is medium. The fissures develop, the rocks are broken, the cores are mostly blocky, a few short columns, partially broken into clastic, RQD is mostly between 25% and 68%, the average is 43%, the rock quality is poor to medium, rock The quality is mostly grade IV and the grade is grade III. The rock mass quality grade is extremely bad, and the rock mass is poor, belonging to the class IV rock mass. Upper Triassic ore top plate clastic lithology mainly feldspar quartz sandstone, siltstone, shale, sandstone gravel, influence by tectonic activity, stability and integrity roof rock difference. The surrounding rock of the ore body is mainly limestone, and some of them are breccia limestone. The integrity and stability are good, and the engineering properties are good.
The continuity of the ore body is good, and there is a phenomenon of local enlargement, branching and refraction. The ore body is generally oriented at about 40°, with a total length of 2318m, a horizontal projection width of 100-670m, an average width of 373m, a thickness of 0.28~32.2m, an average thickness of 4.72m, and an ore elevation of between -54 and -220m. The occurrence is basically consistent with the occurrence of the fault zone. The shape is as follows, and the section is “disc”. The appearance of the different parts changes. The inclination of the ore body is 10°-20°, and the average inclination angle is 12°. The average grade of silver ore is 225.93g/t, accompanied by Au 0.19g/t, Pb 0.20% and Zn 0.65%. The hollow bodies of the ore bodies develop from tens of centimeters to more than ten meters. Most of the holes are mineral ore. The existence of voids may increase the difficulty of mining. The ore industry type is primary silver ore, the natural type is mainly siliceous silver ore, followed by calcium siliceous silver ore, and the average ore weight is 2.65t/m3.
2 develop transportation system layout
According to the occurrence status of the ore body and the proposed mining method, the height of the middle section is determined to be 30m in order to facilitate mining, reduce input and increase output. The development system is a dual trackless ramp development method that meets the mine production scale of 6000t/d. The middle section of the ore is loaded into the downhole truck through the vibrating and concentrating machine in the lower part of the stope, and then transported by the underground truck to the surface ore yard or the selected factory silo through the middle section of the roadway, ramp and surface road. The middle section of the waste rock is transported by the underground truck to the waste rock yard through the middle section of the roadway, ramp and surface road. This results in a full trackless transport mode for underground and surface.
3 mining methods
3.1 Mining method selection
According to the surface environment of the mining area and the occurrence characteristics of the ore body, the mining method is mainly selected from the following aspects:
(1) Considering the Pearl River system, villages, university towns, etc. near the mining area, the surrounding environment is complex, the requirements for environmental protection, water conservation and safety are high, the surface is not allowed to collapse, and the grade of silver ore is high, and the silver ore body should only be filled. The law is carried out.
(2) The ore body has a gentle dip angle, and it has the working conditions of the trackless equipment such as rock drilling rigs and scrapers entering the stope; the use of the trackless mechanized equipment can better adapt to the boring of the ore body and increase the production capacity of the stope.
(3) The ore body has a long trend and good continuity. It has the mining conditions of the panel, which is beneficial to reduce the amount of mining and cutting engineering and improve production efficiency.

(4) The roof of the ore body is not stable, the ore is moderately stable, and the hollow body of the ore body is developed. The exposed area of ​​the working surface should not be too large, and the stope should be arranged in the form of an approach.
Therefore, based on the above factors, a mechanized approach filling mining method suitable for the mining of gently inclined thin ore bodies is proposed.
3.2 Brief description of mining methods
(1) Panel structure parameters. The panel is arranged along the direction of the ore body, with a length of 100-120 m. The length of the panel is 100-120 m along the inclined direction. The width is the horizontal thickness of the ore body, leaving the bottom column 3 m and the top column 3 m. In the panel area, the inlet section is mined and the width of the section is 4m×4m. The mine can be properly adjusted according to the thickness of the ore body and the stability of the ore.
(2) Acquisition and cutting engineering. It mainly includes trackless equipment contact roads, cutting cross lanes, panel ramps, and pans. From the middle trackless transport laneway to the ore body, the trackless equipment contact road with slope ≤15% is used as the passage for the trackless equipment to enter and exit the panel; the contact road arrives at the ore body and then moves along the ore body to dig into the cutting lane, and then goes up from the cutting crossway. Along the ore body tends to dig into the slope of the panel, the slope is ≤15% (when the ore body inclination angle is ≥8.5°, the fold-back arrangement is adopted; when the inclination angle of the ore body is <8.5°, the inclination along the ore body tends to be linear), and The middle section of the cutting cross-section is connected; two Φ=3.0m panel chutes are arranged in the panel area, and the tunnels are transported from the middle section of the roadway to the tunnel, which is connected to the chute, and the vibrating and concentrating machine is installed at the bottom of the chute. The panel mechanized approach filling mining method is shown in Figure 1.

(3) Ore mining. The approach type mining is carried out in the panel area, and the recovery road is arranged along the ore body from the ramp section of the panel. In order to facilitate the walking of the trackless equipment, the access floor is horizontally arranged. According to the stability of the ore body and the surrounding rock of the roof, the approach of the “recover one by one” or “three separates and one one” approach is adopted, and the inlet is filled immediately after the end of the road. The rock drilling mainly adopts Boomer281 imported hydraulic rock drilling rig, and the rock drilling efficiency is 150-180t/shift. The diameter of the blasthole is 45mm, the hole depth is 3~3.5m, the hole bottom distance is 1.5~2.0m, the row spacing is 1.5~1.8m, and the ammonium oil or emulsion explosive, non-electric millisecond detonator and detonating tube blasting are used. .
The mining mainly uses ST-3.5 type 3.0m3 diesel scraper. After the working face is blasted, ventilation is carried out, and the top pumice is treated, and then the ore is discharged by the scraper and loaded into the stopway. The efficiency of the scraper mining is 250~300t/shift.
The ore is discharged from the slip floor vibration excavator to the MT-436B 30t truck, which is transported out of the surface through the middle section of the transport lane and the main ramp.

(4) Ventilation of the stope. The stope mainly relies on the ventilation of the wind flow. The fresh air flow enters the middle section from the slope road and the special air intake well. The tunnel enters the stopway through the vein roadway, the pulse contact roadway and the panel. The tunnel is the single roadway after the tunneling. After the blasting The local fan is used to enhance the ventilation, and the sewage is sent into the upper return air section, and finally discharged through the main return air passage and the return air shaft.
(5) Roof management. After the ventilation is completed, the worker enters the work surface to check the blasting effect, check whether there is a dumb gun and the roof safety condition, remove the pumice stone and loose the rock, and spray water to the explosion pile at the same time. If the top plate is partially unstable, it can be supported by bolts.
(6) Filling of the stope. After the end of the road, the tailings are cemented and filled. The filling pipeline is drilled down to the downhole drilling chamber, and enters the stopway through the middle section of the transport lane, the trackless equipment contact road and the panel ramp. The filling pipe of the alley is Φ146mm×6mm seamless steel pipe, and the filling pipe of the stop is Φ140mm×6mm PVC composite pipe.
Before the filling is completed, the reinforced concrete retaining wall is first laid, the drain pipe is laid, and then filled. The first step of the panel is filled with tailings cement with a sand-to-cement ratio of 1:8. The second step of the recovery tunnel can be filled with waste rock and sand-sand ratio of 1:20 tailings.
(7) Production capacity of the panel. The working face rock drilling and mining are mechanized operations. The single-row production capacity is 150-200t/d. Each panel has an average of 4 routes for production at the same time. The comprehensive production capacity of the panel is 600-800t/d. During the normal production period of the mine, 2 to 3 middle sections are produced at the same time, and the number of working panels is 12-14, which can meet the production scale of 6000t/d.
3.3 Main technical indicators
The main technical indicators of the panel mechanized approach filling mining method are shown in Table 1.

Mechanized panel Approach filling method ton ore mining material consumption in Table 2.

4 Conclusion

(1) According to the occurrence conditions of a mine body and the layout of the transportation system, the mining method is studied to form a technical scheme for the mechanized approach filling mining method suitable for the gently inclined thin ore body.
(2) The ore block is arranged by panel, and the roadway is recovered. The comprehensive production capacity of the panel is 600-800t/d, the panel loss rate is 5%-7%, and the depletion rate is 8%-10%.
(3) Using the filling method to recover the gently inclined and thin ore body, which not only improves the ore recovery rate, but also controls the ground pressure activity and rock movement, and protects the safety of underground personnel, equipment and surface buildings and facilities.
references:
[1] Ning Yulin, Hu Jianhua. Limit exposure area and parameter optimization of gently inclined thin ore body [J]. Mining and Metallurgical Engineering, 2014, 34(1): 14-17.
[2] Zhou Keping, Yan Jianbo, Gao Feng, et al. Research on pseudo-tilt arrangement and parameter optimization of gently inclined thin ore body stope [J]. Journal of Guangxi University (Natural Science Edition), 2012, 37(2): 376-378.
[3] Wang Yuming, Yao Gaohui, Xia Hongchun, et al. Mining method selection and optimization of stope parameters for gently inclined crushed thin ore body [J]. Modern Mining, 2010 (5): 15-18.
[4] Liang Naiyue, Yang Peng, Lu Wensheng, et al. Application of pseudo-inclined single tailings cemented filling mining method in gently inclined thin ore body mining [J]. Non-ferrous metal (Mine Section), 2012,64 (4): 6-9.
[5] Ke Jinfu, Wu Aixiang, Wang Yuming. Controlled blasting technology for broken ore mining stope [J]. Modern Mining, 2015 (7): 36-38.