East occasion gold mine in Zhenghe County, Fujian Province Shi Zhunzhen, is a tectonic erosion in hilly topography, terrain cut deep, the peak elevation of 827.4m, the lowest valley altitude 250m.
There are mainly I# main ore bodies in the eastern mining area, and 4 small ore bodies such as II#, III#, IV# and V#. The main ore body of I# is cut off by the F1-2 fault, and the upper ore body is fault. After the wrong section, the relative height of the ore body is 0-200m, the elevation is 600-360m, the extension is 305m, the inclination is 200-280m, and the true thickness of the ore body is 0.41~10.83m, with an average of 3.90m. The ore body strikes 10°～60°, tends to SE, and the inclination angle is 20°～45°; the lower part of the ore body is the relative fault depression part after the fault is broken. The ore body is buried 410~630m, and the elevation is 210~20m. The strike length is 440m, the inclination is 130-160m, the true thickness of the ore body is 1.32~24.87m, the average is 7.85m, the ore body is 20°-60°, and the inclination is SE, and the inclination angle is 20°~45°.
The ore body distribution is relatively concentrated, and the number of effective ore blocks that can be arranged at the same time is small, and the construction scale is 148,500 t/a. Underground mining is adopted according to the conditions of the ore body, the current mining conditions and the mining technical conditions.
1 mining method selection
According to the geological conditions of the Dongji gold mine, two mining methods were selected: filling mining method and empty field mining method. A comparison of the two mining methods is shown in Table 1.
According to the comparison of the above two mining methods, although the first investment of the first two projects is about 12 million yuan, the direct cost of mining is 2,227,500 yuan per year, but the value of the metal recovered by the first plan is 16.62 million yuan. /a, so program 1 is superior to program 2 in technical and economic advantages; considering that the mine tailings storage capacity is insufficient and the new tailings pond is not yet built, the mine must objectively fill some tailings to the mining In the empty area, to ensure the continuity of the normal production of the mine. Comprehensive comparison, the use of up-horizontal layered tailings filling method mining, mining using non-rail transport equipment (scraper), the mining method has high recovery rate, high degree of mechanization, large capacity of mining block, high labor productivity, etc. .
2 Upward horizontal layered tailings filling method
2.1 nugget structure parameters
The ore block (length × width × height) (80 ~ 100) m × 12m × mine thickness, segment height 10m, route spacing 2.5m, mining method shown in Figure 1.
2.2 mining cutting work
The mining and cutting work includes the mining area slope road, the section roadway, the layered contact road, the slipping mine and the filling return air well, and the cutting cross road. The section roadway is excavated from the slope to the ore body, and each section roadway is loaded with two layers of upper and lower layers, each of which has a height of 2.5 m. A section roadway is arranged at intervals of 10m in the vertical direction. The slope of the slope track and the section roadway is 16.7% at the maximum. Then, the upper and lower disk of the ore body in the middle part of the mining area are separately digged into the return air well and slipped. The mine has a cutting ratio of 33m/kt.
2.3 mining
The mining process mainly includes rock drilling, blasting, ventilation, mining, flat field and filling. From the cutting tunnel along the ore body to the two ends, the YSP45 rock drill is used to hit the eye, and the depth of the blasthole is 2.5m. The stope adopts shallow hole rock drilling, expanded ammonium nitrate explosive blasting, non-conducting blasting detonator blasting and falling mine, and the excitation gun is used for detonation. Scraper out of mine, first put a large pile
On the side, the second break was carried out at the end of the class. The production capacity of the ore block is 250t/d. The main technical indicators are shown in Table 2.
2.4 filling
Immediately after each stratified mining, the preparation work of the stope is carried out. The wooden column and the wooden building partition wall are used at the entrance, and the plastic woven bag or straw bag is used as the drainage layer on the inner side. The gap between the access road and the wooden partition wall and the column should be blocked with cement mortar or epoxy resin to prevent leakage and running. Then, a filling pipe is placed along the top of the approach road to fill the tailings for cementing, and the first layer at the bottom of each stop is filled with a sand-cement ratio of 1:4 tailings (filling body strength 3 to 4 MPa). When necessary, the steel mesh is laid as a false roof during the mining of the lower middle section; the remaining layers are filled with 2.0m of graded tailings, and the remaining 0.5m is filled with sand and sand with a ratio of 1:4. In order to facilitate the shovel loading and walking of the scraper when picking up the previous layer. The pre-buried rapid dewatering pipe is used to dewater the filling body. After layering and filling, the water in the filling body is taken out by the pre-buried rapid dewatering pipe, flows through the communication channel below the filling level, enters the segmented alley ditch, and then remits. Into the middle section of the alley.
2.5 stop ventilation
Install 1 or 2 local fans at the intersection of the mining level and press the fresh air into the working surface. Install a local fan on the upper part of the upper air returning well to pump the dirty air to the return air duct.
3 tail sand filling goaf
Since the mine has been mined for many years, a large number of goafs have been formed in the shallow part, and tailings can be used to fill the gobs. Before filling, first fill a well in the roof of the stope and lower the filling pipe to the stope; then use the wooden column and the wooden building retaining wall in the funnel and the two sides of the stop at the bottom of the stope, and pre-bury the rapid dewatering pipe in the lower part of the stope. Dewatering is carried out, and the cement paste is applied to the surrounding of the retaining wall and the funnel and the contact road to prevent running the slurry.
After the sealed retaining wall and the water filtering facility have passed the inspection, the filling will begin. Try charging first, and you can officially fill it if no holes are found. The filling of the stope is filled in stages. In order to prevent the running accident, reduce the pressure of the filling body on the partition wall. Generally, the 5~7m cement or the corresponding non-glued material is filled first, and then filled in order after initial setting or dehydration until it is full. The filling area is filled in Figure 2.
4 Conclusion
Combined with the actual situation of Dongji Gold Mine, through the comprehensive analysis and comparison of technology and economy, the upper horizontal layered cementation filling mining method was finally determined, and the annual income was increased by 2.4 million yuan, with significant economic benefits.
Author: Lv Zhiwen; Zhenghe County, Fujian source Xin Mining Co., Ltd., Sinosteel Maanshan Institute of Mining Research Co., Ltd., State Key Laboratory of Metal Mine Safety and Health;
Liu Yunqiu; National Engineering Research Center Co., Ltd., Huawei Metal Mineral Resources Recycling;
Article source: "Modern Mines"; 2016.5;
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