Gold mining

Gold mine type diversification, determines the way of exploitation are not the same. The rock gold mine is mainly underground mining and open pit mining; the sand gold mine is mainly open pit mining.
China's river alluvial sand gold mine accounts for a large proportion of total gold reserves, thus forming the current gold mining, mainly based on ship mining, supplemented by hydraulic mining and excavator mining.
The characteristics of China's gold mining are one of a wide range and a small scale. Second, since most of the non-frozen sand gold mines in the north have been developed and utilized, the proportion of frozen sand gold mines in mining and utilization is gradually increasing. The boulders and cemented layers in the farmland above the southern sand gold ore body have become an insurmountable obstacle to gold mining. In addition, the threat of flooding, the thickness of the same ore body and the large changes in burial depth have brought various disadvantages to the construction of the ship. In addition, the external construction conditions are difficult, the investment growth is increasing, and the mining is becoming more and more complicated. China's gold mining has been carried out from scratch, from small (50L) to large (300L), from Heilongjiang to the country, and achieved remarkable results.
According to China's production practices, the introduction of foreign advanced technology, the selection of gold mining vessels from a single fixed chute to a movable tape chute, the complete elimination process. The application of DC motor, silicon-powered transmission power supply device, hydraulic transmission and industrial TV on gold mining vessels has improved the equipment level of gold mining vessels. The successful use of pile-shoulder-type gold mining vessels for mining gold deposits is beneficial to After harvesting, the field is restored.
In the gold mining ship development method, the foundation pit development method is widely applied. On the basis of the conventional foundation pit, two gold mining vessels are simultaneously constructed at one shipbuilding site, and a common foundation pit is applied; in the mine with large groundwater inflow The main foundation pit and pier foundation pit are used for the construction of the ship; the full foundation pit is used on the shallow ore body; the gold mining ship is built on the ice in the north to build a punt; the pier foundation pit is built on the shore. The sewage and airbags are launched, which is convenient for construction and reduces the amount of foundation pits and drainage equipment.
In terms of mining, the application of grass cover method to prevent seasonal frozen soil, the test loose blasting method has achieved certain experience in the treatment of seasonal frozen soil. In the open-air mechanized mining site, the permafrost mine has a successful experience in stripping and thawing Huma County in the same year, in Xinglongjin The use of rift soil pushing technology in mines, especially the application of large-scale bulldozers, can not only solve the need of pre-harvest ice-discharging, but also strengthen the stripping to strengthen mining.
In terms of mining technology, the Wanda Gas Gold Mine successfully exploited large-scale gold ore bodies and accumulated experience in large-scale gold mining vessels crossing the river in Sichuan Baishui Gold Mine. The combined mining of the pile and the first rope improves the production efficiency of the gold mining vessel.
In terms of environmental protection, Jilin Yanbian gold mining vessels first applied sludge sedimentation tanks for sewage purification. So far, this sewage treatment process has been widely used in ship mining mountains. The quarrying method of gravel on the lower fine sand was complemented by the bulldozer Futian.
In the construction of gold mining vessels, we have accumulated a wealth of practical experience. Under the condition of complete equipment and materials, it is only 3 to 7 months to build a gold mining vessel from 50L to 300L.
(1) Open pit mining
China's rock gold mines have a small proportion of exposure and small scale, and some mines have no formal design. Some underground mines are produced on the surface of the open pits, such as the Jigou, Xiaoshan, Shandong and Jiaojia, Shandong.

Tuanjiegou is the earliest constructed large-scale open-pit rock gold mine in China. In the late 1980s, Shandong Cangshang, Guilaizhuang and Liaoning Paishan Buildings were successively built. The gold mine with a scale of over 1000t and the first phase of the Tuanjiegou Gold Mine were designed. The mining capacity was 500t/d, and the second phase expansion in 1991 reached 1200t/d. The design adopts the new technology of steep state stripping Shan State mining and four steps combined operation, reducing the amount of infrastructure stripping by more than 2 million m ³ , saving investment of more than 20 million yuan, introducing computer to define the mining boundary, calculating reserves and preparing mining schedule. In addition, the control blasting technology, pre-pressure and back pressure platform process to deal with the soft foundation of the dumping site and contracting and stripping. It can be seen that the gap between open pit mining technology and developed countries is gradually narrowing.
(2) Underground mining
The technical level of China's rock gold underground mines is multi-layered, including mines with gas-legged rock drills and electric picks, rock drills with hydraulic rock drills, scraper mining, bolt trolleys, bristles, and equipment. Mines (such as Sanshan Island) characterized by auxiliary operations such as pharmacies, as well as mechanical rock drilling, but the transportation and auxiliary operations are all manual mining methods.
1. Develop and upgrade the transportation system
According to the statistics of the Ministry of Geology and Mineral Resources in 1987, the number of quartz vein deposits in China accounts for 70%. These deposits are small in scale and the distribution of veins is discontinuous, which is suitable for multi-wellfield development. The development system is mainly based on Pingyi, Pingyi-shaft, shaft-inclined well and other systems. According to the statistics of 31 mines, Pingshuo has a 32% development; shaft-sloping well development and single-shaft, Pingyi-blind wells each accounted for 12.9%. The Sanshandao Gold Mine is the first time for the gold system to use the slopes that pass through the surface to assist in the development of the mine. In addition to the extensive use of ordinary single rope lifting, shaft reinforcement has installed multi-rope friction lifting system in Jiaojia Gold Mine and Sanshandao Gold Mine. Dashuiqing and other gold mines have transformed single rope lifting into friction lifting. This advanced lifting mode is safe to operate. Reliable, low operating costs, reduced access road engineering and related projects. A summary of the typical mine development system is shown in Table 2 below.

Table 2

Stage transportation: The main transportation of the main mines is mostly 7t electric motor vehicles. Local mines are transported by 1.5~3t electric vehicles.
2. Tunneling
The shafts are mostly round, with a diameter of 3 to 5.5 m. Generally, multi-machine rock drilling, detonating tube water-sealed blasting, large-capacity buckets are installed, and the average lane speed is 40 m/month. The key mines in the roadway excavation are mechanized, chiseled, loaded and transported, and the average laneway speed is 40~50m/month (see Table 3 for the average excavation profile). A small number of mines, such as Jiapigou and Jinchangyu, use trolleys to drill rock, load rocker installations, bucket-type transfer vehicles or shuttles to form a mechanized operation line, with a station efficiency of 1.75m/(Taiwan·Ban). (Golden Factory). However, quite a few local mines are manually installed and artificial carts. In recent years, the Jinchang antimony mine has successfully drilled into the patio with deep hole blasting, with an average footage of 5.7-6.6 m/d. This method has the advantages of fast well formation, good working conditions, wood saving and low cost. [next]

table 3

3. Mining method
At the beginning of the founding of New China, there were almost no formal mining methods in the Yanjin underground mine. After nearly 40 years of development, not only the mining methods are complete, but also many combination schemes have been derived, which basically solves the mining problems of gold deposits, such as creatively. The combination of the retention method and the comprehensive method has solved the mining problem of the inclined thin ore body; the retention method has been continuously improved and improved; the tailings and tailings cement filling method has been introduced, which has filled the blank of the mining method of the gold mine and received a reduction. Loss of depletion, delays in rock movement and surface subsidence, and safe operation. The test succeeded in the downward cementation filling method and the long anchor cable pre-control top and vertical split tail tail cement filling method, which solved the problem of safe mining of high-grade ore bodies with broken rock. The successful trial of the large-diameter deep-hole mining method and the three-high explosives has opened up new avenues for improving the mining intensity of mines. The introduction of micro-scrapers is a welcome step for small mines to derail (see Table 3). At present, the mining method is mainly based on the empty field method and the filling method. According to the statistics of 17 mines in 1987, according to the calculation of mining volume, the empty field method accounts for about 69%, the filling method accounts for 24%, and the rest accounts for 7%. The empty field method is mainly based on the shallow hole retention method, the comprehensive method and the comprehensive method of retaining minerals (see Table 4 below for details).

table 3

Due to the occurrence of veins and people's traditional habits, the use of mining methods has a certain regionality, such as the shallow hole retention method and filling method in Shandong Province (38%, 25% respectively); Hunan Province to cut the wall Dry filling method is the main method (accounting for 64%); Henan is dominated by the comprehensive method and the comprehensive method of retaining minerals (25% and 35% respectively); Inner Mongolia is mainly based on the wall-cutting and dry-filling method (48%).

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