Shallow hole shrinkage stoping method is the most widely used of underground metal mine mining method for a range of applications, the application is more common in small and medium steeply inclined thin and ultra thin veins of mine. Wei Mining five antimony deposits form vein mining is to use this method, since the shallow hole ore mining process is simple, easy to manage, low equipment requirements and lower mining costs. Wuyi Mine has always adopted the method of shallow hole retention and retention of pit wood, which has achieved good economic benefits.
I. Overview of the mine
The Wuji Polymetallic Mining Area Jianniu Mine is located about 35km southwest of Jinchengjiang Town, Hechi City, Guangxi Province. It is a small mining enterprise owned by Hechi Wuji Co., Ltd. The Jianzipo deposit began mining in the Guangxu period of the Qing Dynasty. In 1985, the mine was transferred to the predecessor of Wuji Company, Guangxi Hechi City Nonferrous Metals Co., Ltd., and the designed production capacity is 80,000 t/a.
Dan Wei mining area is located five metallogenic belt of the southern section of the pool, porcupine slope deposits located near the dike near the core part five central anticline, located in the Devonian satisfied that the standard set of the first, the second paragraph of sericite shale, argillaceous dolomite, dolomite containing iron, sericite mudstone, wherein the second section is the main mineralized horizon porcupine slope deposits. The deposit is mainly controlled by a group of north-northwest compression-torsion fault zones. The veins of the Jianpipo deposit are produced in the torsion zone of the porcupine slope. The twisted zone is composed of a group of nearly equal torsional pressure-compression fractures. More than 30 pieces have been found, appearing in groups, ranging from tens of meters to thousands of meters. The fault zone runs north-southwest and has a steep dip angle, generally 60°-80°. There are “in†branches along the strike and inclination, and some are arranged in geese. The thickness of the fracture zone varies greatly, ranging from a few centimeters to 3 m. The ore body is vein-like, and the veins are distributed in groups along the torsion zone. The main metals are mainly silver , lead , zinc and antimony, with elements such as cadmium and gallium .
The deposit is a medium-low temperature hydrothermal filling deposit after the magma period. In the mining area from 308 to 0.95km 2 , there are 32 veins in total, of which J 3 # , J 7 # , J 31 # and J 31-1 # 4 main mineral resources reserve, accounting for 79.0% of the retained resources. The remaining veins are small in size and belong to the secondary veins on the side of the equal main vein.
The Jianpipo Mine adopts the Pingyi-inclined well development system. The pit is transported by rail. The alley is a manual cart. The inclined shaft is hoisted and raised. The mining elevation is 10~400m, the maximum mining depth is about 400m, and the stage height is 30m. about.
Second, the technical conditions for mining
The veins of the Zhu pig slope deposit are found in the strip-shaped mudstone and the iron-bearing dolomite sericite mudstone. The surrounding rock is generally firm, and the Platts hardness f is 5-6. The ore and surrounding rock fissures are not developed, and the stability is better except for the weathering zone and the veins with high carbon content and severe weathering and fracture. The ore bodies are distributed in veins and veins along the torsion zone, and their occurrence is strictly controlled by the occurrence and morphology of the fracture surface. Most of the veins tend to be 70° to 90°, and the west side has a small tendency of 250° to 270° and an inclination of 60° to 85°. The veins are thinner, and the larger ones are 1 to 2 m, and most of them are below 1 m. The average grade of ore is low, lead is 0.862%, zinc is 3.813%, and silver is 82g/t. More complex ore mineral composition, the main sulfide minerals are sphalerite, copper ore, bornite, arsenopyrite and the like. Although there are many veins, the main veins are spaced apart and can be mined. There is no large water body on the surface of the mining area. The hydrogeological conditions of the deposit are simple, and the mining work is only affected by rainfall seepage and weathering fissure water filling. More than ten years of mining practice has proved that there is basically no groundwater infiltration under the well, in fact, near the water deposit. Except for the mining company's factory buildings and auxiliary industrial facilities around the mining area, there are no residents and other permanent buildings and farmland, and the surface is allowed to fall.
Third, mining methods
According to the occurrence conditions of the veins of the Jianpipo deposit, the mining technical conditions and the equipment level of the mine, the long-term use of the mine has the advantages of simple structure, convenient management, small amount of mining and engineering, easy control of the process technology, and relatively simple equipment. The shallow hole retention method with many advantages is used for mining. Due to the unstable grade of the veins, for the grades where the grade is not high or the ore is not very stable, the typical top-dump column and the retention method are used for mining; for the higher-grade sections, the roads are opened without leaving the column and the bottom column. The well retaining method is used to fully recover the ore. At this time, the pits are used to construct the artificial false bottom and the smoothing patio. The practice of the Jianpipo Mine proves that the mining resources can be fully recovered and the economic benefits of the mine can be improved by using the pit-wood false bottom retention method. This article mainly introduces the use of this method in the Jianpipo mine.
Figure 1 shows the structure of the ore block of the Jianzhupo mine pit.
Fig.1 Schematic diagram of mining method for pit and wood false bottom mining
(1) Elements of the nugget
The in-pulse stage is used to transport the alleys, and the ore blocks are arranged along the ore body. The height of the stage is 30m, the length of the mine is 30~50m, the width of the ore is the thickness of the ore body, the top column and the artificial false bottom are both 3m, no column is left, and the funnel spacing is 3~4.5m.
(2) Precision cutting
The transport lanes are generally driven along the lower veins along the veins. A 2m×2m patio is placed on each side of the mine, one side of which leaves a forward patio when mining with the previous one, or an advanced patio that passes through the middle section along the vein, or the other side is mined The work is oriented upwards and is erected with pits. When erecting the patio, the vein should be located in the center of the cross section of the patio as much as possible. The upper and lower exits of the patio should be located in the side wall of the transport lane. The cutting work is relatively simple, picking up the roof from the roof of the transportation roadway for about 3m, and setting up the false alley and the funnel. The diameter of the pits for erecting the false bottom and the funnel is 15-20 cm.
(3) Recovery
The mining room mining adopts stratified and stepwise operation, the stratification height is controlled at 1.8~2m, and the working surface length of the step is 10~15m. The mining work includes rock blasting, ventilation, partial ore mining, dome, flat field, broken large blocks and erected patios.
1. Rock drilling. Generally, the YSP-45 rock drill is used to drill the upward blasthole, the depth of the eye is 1.82~2m, the row spacing is 0.8m, and the eye distance is 0.5-0.8m.
2. Blasting. The emulsion detonation system is detonated by emulsion blasting and detonating tube detonator blasting. The blasthole charge coefficient is 60% to 70%, and the orifice is filled with gunpowder.
3. Ventilation. After the shooting is completed, the local fan is used to discharge the gun smoke. The fresh air flow enters the working surface from the smoothing patio on the side of the stope, and the dirty wind is discharged into the upper and middle return air passage through the veined courtyard on the other side of the stope.
4. Partial ore mining. After each blasting, the ore weight is used to release about 30% of the ore from the mining funnel to ensure the working space height of about 2m. In order to reduce the workload of the flat field, the amount of ore released by each funnel should be determined according to the blasting situation. After the end of the ore in the entire stope, the ore remaining in the mine will be released.
5. The dome is flat. After the partial mine discharge is completed, the squad leader and the safety officer enter the mining work surface to check the situation, and the top plate and the upper and lower plates are removed to ensure the safety of the work surface. Then, the surface of the ore pile on the working surface is leveled to start the next cycle of rock drilling.
Fourth, the main technical and economic indicators of the stope
The mining efficiency is 50t/shift, the mining efficiency is 7.1t/work, the ore depletion rate is 20%~22%, the loss rate is 12%, and the mining coefficient is 40m 3 /kt.
Main material consumption: explosive 0.6kg/t, detonating tube 0.55 hair/t, steel fiber 0.05kg/t, pit wood 0.005m 3 /t, alloy sheet 2g/t
Five, there are problems
(1) The degree of mechanization is low. The work of handling loose rock, leveling the ground, breaking large blocks, erecting artificial bottom columns and funnels is mainly done by manpower, and the workers are labor intensive and inefficient.
(2) The consumption of pit wood is large.
Conclusion
Wuyi Mine adopts the shallow hole retaining method of pit wood, the mining process is simple, the workers are easy to master; the mining and cutting engineering quantity is small, the mining cost is low; the mining working face can change with the change of the ore body, the ore loss is small, the depletion is small Etc. More than ten years of mining practice has proved that the use of pit-wood shallow hole retention method to mine thin veins with higher grade has achieved good economic benefits.
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