1. Mining technology and equipment for stone mines
At present, there are still many stone mines in China that use the backward method of drilling and blasting to produce stone blocks. Not only is the production efficiency low, but the operation is unsafe, especially because the rock mass is broken due to blasting, which seriously damages the stone resources. The size of the blocks is irregular, and even scrapped due to cracks, and the yield rate is very low. It is estimated that only 5% to 8% of the mining volume can be processed into timber by the method of drilling and blasting. In the early 1980s, some developed countries in the stone industry have banned the use of explosive blasting methods to mine stone, and replaced them with advanced technologies such as diamond bead wire saws. It can be said that this is a sign of modernization of stone mining technology. An important indicator to measure the modernization of stone mining technology is: the number of cubic meters of blocks mined per person per day. People in the International Department believe that China's stone mines have low productivity. The reason is the lack of mechanized equipment, backward mining technology, and poor production management. Some stone mines have an average annual mining volume of only a few hundred to a few thousand cubic meters. A few stone mines have an annual mining volume of more than 10,000 cubic meters and an annual per capita output of 6m3. . The equivalent monthly output per capita is only 0.5m3, which is lower than India. As we all know, India is also a large stone producer. However, its granite mine is small in scale and has no modern equipment, so the productivity of stone blocks is very low. Only 1m3 per person per day. Finland is the largest stone exporter among Scandinavian countries. Its granite mine production system is world-class. It exports at least 250,000 tons of granite every year, and its mine production efficiency is as high as 40m3 per person per day. The productivity of stone mines in South Africa is at a medium level, with a daily average of 8-10m3 per person.
2, stone processing machinery and equipment
In the past ten years, the development of stone machinery and equipment in China has made great progress, and the degree of automation of some single machines has reached the international advanced level. But in terms of high-end technical equipment, China has not yet produced it. In terms of the degree of automation of the overall production line of stone enterprises, there is still a gap compared with foreign countries. Some production links still rely on human operations, which not only affects the production efficiency, but also causes unstable factors in the quality of finished products due to the low quality of employees. Even though most of the stone companies in Italy, the world's stone powerhouse, use highly automated production lines, they still need personnel with certain stone knowledge and experience to master the process parameters of the processing process to produce top-quality stone products.
At present, many foreign stone mines, especially granite mines, have fully adopted diamond bead wire saws for mining blocks, and in the sawing process of granite blocks, multi-line diamond bead wire saws have also been promoted. However, many stone companies in China still use old-fashioned frame saws. One of its significant advantages is the lower cutting cost, but there are many disadvantages:
①The assembly cost is high, about four times that of a diamond bead wire saw;
②There are many operators, and at least two people are required to operate. More people need to work together when changing the saw blade;
③The cutting speed is slow, and the cutting speed of the old frame saw is only 2cm/h. The cutting speed of the new frame is only 3.5-3.8cm/h. The cutting speed of the diamond bead wire saw is as high as 20cm/h, and it may be increased to 30cm/h;
④The surface of the plate cut by the frame saw is rough and the flatness is poor, so the polishing speed is low, 100cm/min, while the surface of the plate cut by the diamond bead wire saw is smoother, and the polishing speed can be as high as 160cm/min. Thus reducing the grinding and polishing processing time;
⑤Energy consumption and material consumption are relatively high;
⑥ The disposal of scrap steel mortar and dust on the work site cause serious environmental pollution.
3. Quality of finished stone
The people in the international stone industry believe that the quality of finished stone products in China is not high because the stone processing equipment and techniques used are lagging behind other countries. Take the production of granite facing tiles as an example. Most of the granite blocks mined from the mine have irregular shapes and different sizes; diamond circular saw blades with a diameter of 1m and 1.6m are generally used for sawing into granite slabs. The quality of the saw blades is not high and it is cut. The plate is usually polished and polished with a rocker arm, and the processing is mostly manual operation, that is, the use of a highly automated grinding and polishing machine, the quality of the abrasive used by the matching grinding head is poor; the polished plate is sawed by an ordinary cross cutter A certain size, the production process is low in automation. In the 1990s, many European countries have adopted advanced sawing machines and high-quality saw blades. The production of granite facing tiles is almost fully automated. The latest generation of sawing machine is equipped with as many as 80 diamond circular saw blades with a diameter of 1m. Due to the use of high-quality diamonds, the linear speed of the saw blade can be as high as 35m/s, and the feed speed is 17m/min. Each saw blade The sawing rate is 1m2/h. In contrast, the sawing machine used in China is generally equipped with only 5 saw blades with a diameter of 1m or 1.6m, and the quality of the saw blade base and diamond is poor, so the saw blade line The speed is limited, 17m/s or 27m/s, and the cutting speed is slow, 5m/min. The cutting rate of each saw blade is about /0.3m2/h.