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Zhangjiakou gold mine in accordance with the conditions of this mining technology, after years of exploration, successfully applied and tested approach full recovery type mining method multiple programs.
First, mining technical conditions
Changgiakou hydrothermal gold deposit fissure filling type gold-bearing quartz veins and altered rock deposit, the mineralization and crushing with a pressing belt. The mining area is affected by multi-stage tectonic movements. The faults and joints are very developed. There is a fault along the ore body trending average of 5-7m. There are often small faults and dense joints and fissures between the large faults. The rock is divided into pieces.
The shape of the ore body is complex, and the thickness and inclination angle vary greatly. The inclination of the ore body is generally less than 10°, with an average of 4°; the average thickness of the ore body is 1.56m. The top and bottom of the ore body are undulating. Ore stone, f = 13, the joints are very developed. The gold content of ore is 3.5~3.7g/t, accompanied by silver and lead . The content of silver is 7-8g/t, and the content of lead is 0.2~1.13%. The grade distribution is uneven.
Second, parallel approach comprehensive mining law
The nugget is 40m long along the strike and 40m long along the slope. The bottom column is slanted 3 to 4 m long without leaving the top column. Dig into the mountain on both sides of the quarry, as a pedestrian, ventilation, and transportation materials, and as a mine roadway. The structure of the mining method is shown in Figure 1. At the time of mining, the mining side of the quarry will go up every 4 to 5 m from top to bottom, and an approach will be made until the other side of the ore block. The access section is 1.8m×1.7m, and is drilled along the bottom of the ore body. When the thickness is less than 1.7m, the access height is 1.7m, and when the thickness is more than 1.7m, it is equal to the thickness of the mine, but not more than 2.5~3.0m. The surface of the blasthole is the same as that of the open tunnel. The vertical barrel-shaped sluice is used. After the tunnel is drilled to the other side, the pillar is retracted according to the thickness of the ore body. The mining holes are staggered, the spacing between the rows and the spacing of the holes are 1.0m, and the hole depth is 1.5m. In the process of mining, the grade is low or the stone section is reserved as a pillar. The ore that is harvested is transported out by the electric raft and the sputum mine.
Figure 1 Schematic diagram of the comprehensive method of the parallel approach of Zhangjiakou Gold Mine
1 - stage transportation roadway; 2 - bottom column; 3 - ore body; 4 - way; 5 - column;
6—耙 Mine is more than the car room; 7—Upper stage transportation roadway; 8—Uphill; 9—Upper stage nugget bottom column;
10—upper stage goaf; 11—irregular ore column; 12—the ore block goaf
The approval of the upper mountain is generally supported by wooden sheds (interval or dense), the stability of the root top plate, and all or part of the approach is supported by wooden sheds. When mining the pillars between the roads, support them with wooden pillars or rafts according to the condition of the roof. With the advancement of the backward mining, the empty area is closed with wooden pillars along the inclined upper part of the stope, so that the roof surrounding rock naturally falls to fill the gob.
The main technical and economic indicators for the application of this mining method are listed in Table 1.
Table 1 Main technical and economic indicators of mining methods
Indicator name
Value
Indicator name
Value
Ore production capacity /t·d -1
55.91
Explosive consumption / kg · t -1
0.49
Ore loss rate /%
7.41
Pit soil consumption / m 3 · t -1
0.002
Ore depletion rate /%
8.5
Mining cost / yuan · t -1
15.52
Mining work surface ergonomics / t · work class -1
3.98
Note: The indicators in the table are actual data for 1990.
3. Jingtian Road Comprehensive Mining Law
Compared with the above-mentioned parallel approach comprehensive mining method, this method is characterized in that a strontium mine is generally drilled in the center of the ore block as the main moving roadway for the ore. From the Yankuang up the mountain, every 4 to 6 m from top to bottom, the parallel-oriented approach is drilled to the sides to the boundary of the ore block. From the end of the approach, the mining work will go up and down into Ogawa to the adjacent approach, and return to the mining roadway in the center of the mine. There are generally pillars between Ogawa, and the pillars can be partially recovered according to the stability of the roof. The ore mined from Ogawa was first manually transported to the road, and loaded into the car with a 30 kW electric raft in the uphill mine. In this way, the mining house is harvested by excavating the tunnel, Ogawa and recycling the pillars between Ogawa. This name is obtained because the way of its approach is to form the word "well" or "field" on the plane.
In the process of mining, depending on the stability of the roof, support the approach and Ogawa, generally with wooden shed support.
Fourth, the fishbone approach comprehensive mining law
The difference from the above-mentioned comprehensive method of the well-field approach is that the method changes the vertical channel between the approaches to the diagonal arrangement, that is, the angle between the original Xiaochuan and the two adjacent roads is 90°+90°. , changed to 45 ° + 135 °; so that Ogawa and the approach between the formation of a fishbow-like plane layout, as shown in Figure 2. The advantage of this arrangement is that the original right-angle transport system is changed to oblique transport, which reduces the number of haulage operations, eliminates the need for manual reversal, reduces work labor intensity, and improves labor productivity.
Figure 2 Schematic diagram of the full mining method of the fishbone approach
1—irregular ore column; 2—mined area; 3—inclined road (Ogawa); 4—electric pick-up winch;
5—mine body; 6—bottom column; 7—horizontal approach; 8—loading electric winch;
9—Funnel; 10—Main raft (耙耙上山)
V. Evaluation
In the Zhangjiakou gold mine, when the roof is unstable and the gently inclined thin ore body is firstly used, the wall caving method is adopted first, and the effect is not good. After years of production and testing, various forms of comprehensive methods of approaching and mining are used, which is better. Effect.
The essence of the approach-type comprehensive mining method is to use the way back to the ore to make the workers work under the smaller exposed surface, which is safer. Even if they encounter the broken belt, they can also use the wooden shed and other supporting methods for mining. In the process of mining, it is also possible to leave the stone layer and the lean section as the pillar of the pillar according to the rich and poor and the inclusions in each section. For pillars that need to be recycled, all or part of the recovery is carried out depending on the stability of the roof. After the end of the mining, the goaf is closed and allowed to collapse on its own.
According to the layout of the approach, the mine uses a variety of options such as parallel approach, mine approach and fishbone approach. The evolution of these programs is mainly to solve the problem of ore transportation in the stope, simplify the transportation system, reduce the number of reversals, facilitate the electric transportation, reduce the manual labor of workers, and improve the transportation efficiency and labor productivity.
The production practice of the Zhangjiakou gold mine over the years has shown that the comprehensive mining method of the approach mining is applicable to the following mining conditions: the inclination of the ore body is not more than 30°; the thickness of the ore is not more than 3 m; the roof is unstable and stable. The mining method has strong adaptability to unfavorable mining conditions such as uneven mineralization, inclusion of stone layers, instability of ore body elements.
The main disadvantage of the comprehensive method of approaching mining is that the ore must be transported several times, the mining efficiency is low, the physical labor of the moving and supporting workers is heavy, and the labor productivity is low.