The basic situation and development of the mining and mining method in China's gold mines

First, Shrinkage Method in the basic situation of our country gold mine

The mining method is the earliest, most successful and most extensive mining method used in underground rock gold mines in China because:

(1) Most of China's rock gold deposits are quartz vein type and quartz vein-altered rock transition type, and the steeply inclined thin veins with stable ore deposits account for a large proportion, which is in line with the technical conditions for mining method. According to the survey statistics of 53 mining areas, the ore deposits of the rock gold deposits accounted for 28%, the steep slopes accounted for 32.2%, and the thin veins accounted for 63.4%. About 30% of the mining conditions are met.

(2) The application of the mining method for decades has proved that the mining method has the advantages of simple stope structure and simple mining process, less equipment required, convenient production management and easy control of workers. Therefore, it is small and medium-sized. Mines, especially township and local enterprises, are very popular. Due to the small scale and wide distribution of China's rock gold deposits, the scale of Yanjin underground mines is mostly small and medium-sized. According to the statistical data produced in 1988, medium-sized mines accounted for 12.23%, and small mines accounted for 82.53%. Medium-sized mines accounted for 11.96%, and small mines accounted for 86.13%. The total volume of small and medium-sized mines is 94% to 98%.

At present, the rock gold mines using the mining and mining method mainly include gold mines such as Zhaoyuan, Xiaonanxi, Jiapigou, Wulong, Erdaogou, Jinchangtun, Rushan, Hatu and Longshui. Most of the ore bodies are quartz veins with steep slopes and veins, and the ore rocks are stable at medium or medium levels (Table 1).

Table 1 Mining technical conditions for major mines using the retention method

The height of the stage is generally 40m, and the length of the nugget is 40-60m, leaving a bottom column, a top column and a column. Most of them use the bottom-bottom electric shovel to produce the bottom pillar structure, and the upper blast hole is mined, and the local ore deposit and a large amount of ore are carried out from the bottom of the stope. The large column is used to recover the pillars. Some of the mined areas are filled with waste rock, but many mines are allowed to fall naturally and will not be treated.

The main technical and economic indicators of the retention method are listed in Table 2.

Table 2 Main technical and economic indicators of the retention method

Second, the use of the mining method of mining technology and major scientific research results

In the past 20 years, due to the continuous advancement of mining technology in rock gold mines, the mining and mining method has been continuously improved and perfected in terms of structural parameters, mining layout, mining technology and scope of use, and has formed a number of deformation plans for the retention method. Reduce ore loss and depletion, and expand the scope of use of the mining law.

The technological progress and scientific research results of the retention method can be summarized as follows:

(1) Improve the bottom structure of the mine. In the long-term production practice of Zhaoyuan and Wulong Gold Mine, the bottom structure of the mine is continuously improved, the card leakage accident is reduced, the mining efficiency is improved, and the ore loss of the bottom column is reduced. For example, the improved funnel structure is a flat-bottom structure of an electric raft or a rock-boring machine, and the vibrating ore concentrating machine is used instead of the wooden funnel to release the ore, and the artificial bottom column is substituted for the ore bottom column.

(2) Improve the mining method of pillars or mineless pillars. The new process of synchronous mining of mining room and pillar in Wulong Gold Mine simplifies the process, improves the working conditions of pillar mining, improves the recovery rate of ore and ore, and provides new mining for mining ore mining. Way. The practice of the non-mineral column retention method in Pingdu City Gold Mine has provided successful experience for rock gold mines with similar conditions.

(3) Applying controlled blasting technology back to the mining room. When the top of the ore is not stable enough, after the mine is dropped into the blasthole, the amount of sputum is large and unsafe. The Jinchangyu gold mine was changed to horizontal blasthole controlled blasting or leveling alternate blasting, which has good effect, improved mining efficiency, reduced bulk output rate and improved mining operation conditions. The Dongtongyu gold mine uses horizontal holes to control blasting to reduce the damage to unstable rock.

(4) Develop a deformation plan that adapts to the change of vein morphology. Wulong Gold Mine arranges double-layer ramp mining or ore mining ore mining in the local slowing position of the dip angle of the ore body to reduce the retention and loss of the ore in the slower inclination. The Zhaoyuan Gold Mine proposes a matching arrangement method and a recovery method or a slanting electric shovel method for the branching complex complex vein or the end triangle vein.

(5) Creating a deformation plan for the retention of minerals that is not stable to the surrounding rock. Dongtongyu gold mining Q No. ₁ vein wall rock instability, successfully tested a "static" Shrinkage Method, local stope mining process ore from the stope is not the bottom, but rake in from the pile surface mine in mine house The local ore discharge at one end is released, so that the ore remains in a stationary state during the mining, which can better support the surrounding rock and prevent its deformation and damage. The Jiapigou gold mine has also tested this scheme and achieved good results. The Liucun Gold Mine has a steel plate chute in the center of the stope for local mining. The Erdaogou Gold Mine constructs a waste rock support rock in the stope, and the “low-stage” mining of the Zhaoyuan Gold Mine is used for storage. Ore or local waste rock, which supports the surrounding rock to prevent its falling off, and the mineralization method can make the mining and mining method applicable to the unstable conditions of the surrounding rock (especially the upper plate) and expand the scope of use of the retention method.

(6) Create a method of cutting the wall and retaining minerals suitable for extremely thin veins.

(7) Treatment of ore ceilings. During the recovery period of the mine, for some reason, the local mining often has a suspended roof phenomenon, which causes safety hazards to the workers on the surface of the mine. The Hami Gold Mine provides practical experience for the analysis and treatment of ore ceilings to eliminate the above-mentioned safety hazards.

Third, the main problems in the retention of mining law

After decades of production practice and scientific research, the retention method has been greatly improved and its scope of use has been expanded, but the following main problems remain:

(1) During the recovery period of the mining house, the dome, the secondary crushing and the flat field are large, the labor intensity is high, and the operation safety is poor. For these small and medium-sized gold mines, these operations are almost impossible to mechanize at this stage.

(2) When recovering thin veins with a large thickness (2~5m), it is generally necessary to retain the ore pillars (for example, when constructing artificial bottom pillars, it is necessary to retain the pillars and the top pillars). When the large blasting method is returned to the mining column, the ore loss and depletion are both large. However, using the experience of synchronous mining of the pillars of the Wulong Gold Mine, the continuous ore body with a large extension of the vein direction is complicated in process and generally difficult. grasp.

(3) At present, after the mining method of the underground rock gold mine is retained by mining, there is a large amount of goaf left in the ground, and generally no treatment is done. This is a great safety hazard. If it does not attract attention, the accident with major losses is certain.

Fourth, further improve the way to retain mineralization law and its development prospects

Due to the characteristics of the occurrence of rock gold veins in China (the steeply inclined thin veins account for a large proportion), the mining and mining method as a mature mining method must have its broad application prospects.

According to the current problems in the mining and mining law, it should be further improved from the following aspects:

(1) According to the mining technical conditions of the ore body, the method of retaining ore is correctly selected. The inclination of the ore body is greater than 60°, the thickness of the ore is 0.4 to 4.0 m, and the stability of the ore is the best condition for using the retention method. When the dip is slowed down, due to the difficulty of retaining ore in the lower plate, it should be evolved into a comprehensive method of retaining ore. When the dip is partially relieved, the experience of the Wulong gold mine is used for hydraulic ore mining, and the deformation scheme of the double-deck mine is used. When the thickness is less than 0.4m, the wall-filling method should be used. When the thickness is more than 4.0m, the upper layer filling method should be adopted; when the thickness is 0.4-2.0m, the column is not left, and the length of the vein is 2.0-4.0m. Not big, to promote the experience of mining and mining pillars synchronous mining, when the surrounding rock (especially the upper plate) is not stable, the mining mining should use controlled blasting ore (Golden 峪 gold mining experience) and "static" mining ( The Dongtongyu gold mine experience) deformation scheme or local filling and retention method (Erdaogou gold mine experience) scheme; the ore and surrounding rock are not stable, and when the gold grade is high, the downward cementation filling method should be used instead. Qianhe Gold Mine experience).

(2) Studying the method of mining pillars. Due to the large blasting back to the mining column method, the ore loss and depletion are large. Generally speaking, this method is not suitable for alloy mining. Under the condition that the pillar must be retained, there is no proper process at present, and the pillars account for a large amount of ore. Carrying out the actual research work in this area has great practical significance for making full use of the gold resources.

(3) Simplify the stope structure and the mining process. Not leaving and leaving less pillars is an important aspect of simplifying the structure. Flat-bottom electric ramp or rock loader mining is a good structural form; without a column to construct a smooth road patio, the contact roads on both sides of the mining mine can be omitted (the drilling of these short roadways is labor intensive); The combined artificial pillar is an important practical issue for gold mining. The alternating vertical control of the blasting method can simplify the operation of the manual work of the dome flat field, and should be further researched and promoted.

(4) Processing the gob area. The Pingdu gold mine constructs a layer of 0.5-1.0m thick reinforced concrete pillars every other stage, filling the goaf with waste rock or tailings, and the Jinchangyu gold mine opens the "skylight" from all over the empty area. Experience is very worth promoting. According to the different existence states of the goaf, the corresponding treatment methods are studied to prevent the occurrence of major accidents caused by the sudden and large-scale fall of the rock mass.