For granite mining, the first mining area should be selected according to resource conditions and market demand, and the mining boundary, mine production scale, and mine working system should be determined. Mining is carried out on the basis of comprehensive analysis of the natural environment and economic and technical conditions. Mining processes can be divided into pioneering transportation, stripping and mining. 1. Develop transportation and loading The task of developing transportation is to open up the transportation route between the mining industrial field and the working steps in the mining site and the transportation route to the waste rock site. Commonly used modes of development for granite open pit mines are: 1) Highways develop car transportation. This method is flexible and can fully utilize the efficiency of loading equipment . It is widely used. 2) Ditchless development of mast crane lifting, this method does not need to dig the transport channel from the surface to the mining step, but directly into the transport equipment by the mast crane. This method has a small amount of engineering and low investment, but it is limited by the capacity and working range of the mast crane. In addition, there are slope hoisting machines to develop trolley transportation, road vehicles and mast cranes to jointly develop transportation. There are two types of loading equipment for loading waste materials into transportation equipment. The mast crane is fixed. This type of equipment has a high lifting height and a large lifting capacity, and it has both loading and transport functions. The crawler crane and the tire crane are mobile loading equipment. These equipments are flexible, but the lifting height is high. The lifting weight is small and it is not suitable for loading large-size blocks. The transportation of waste rock in mines is often used in manual carts, front loading machines, bulldozers, cranes, automobiles and other equipment. 2. Block mining is roughly divided into the following processes: (1) Cover stripping: It is a process of stripping off the floating soil and non-mineral rock layers above the ore to facilitate the mining of ore. At present, many methods of manual stripping are used in mines, and only some mining sites use machines such as bulldozers and wheel loaders for stripping. (2) Separation: It is the second process of separating the bar-shaped stone from the original rock of the ore layer. Limited to the existing mining scale and production methods, mining and mining are basically two methods of artificial chiseling and controlled blasting. The artificial splitting method is a manual artificial chiseling and wedge-cutting manual splitting. This method has relatively high labor intensity and low efficiency, but the rate of outbreak is high and easy to shape. The controlled blasting method is to use a hand-held wind drill to make an eye. Gunpowder or small rolls are controlled for blasting. (3) Top flip: the strip stone is tipped over to facilitate cutting and separating. There are a variety of top-turning tools such as manual jacks, hydraulic top stones, push air bags and traction methods. At present, the main use of the mine is the jack and the traction method. (4) Disintegration: It is to divide the strips of stone into blocks of raw materials or blocks according to the required scale. The method of disintegration is similar to the separation method. The main methods are manual wedge cutting, chiseling and splitting, and controlled blasting. (5) Shaping: Shaping is to divide the blanks after the blanks into a finished product that meets the scale through certain processing. Methods of shaping include manual hammering, small hand-held drilling rigs , hand-held rock drills , and beaded diamond wire saws and shaping machines. At present, the methods used in the mines are mainly simple methods such as manual hammering and chiseling, and no mechanical work. (6) Lifting loading: It is a process of transporting processed and formed blocks to a transportation vehicle. The tools used for lifting can be varied. Mines currently use mast cranes, and there are also a few mining sites that use car cranes, loaders and crawler cranes. (7) Clearing: It is a process of transporting the broken gravel from the block processing site. Second, the technical requirements for granite mining Under normal conditions, when the production stripping ratio is around 0.3, the lowest economic block rate of granite ore is 15% to 25%. (1) When the height of the step of the mining site is mobile crane, the step height is 4~6m; the small mast crane is used, the step height is less than or equal to 14m; for large mast crane, the step height is less than or equal to 62m. The slope angle of the stepped slope is generally 90°, and the final slope angle is determined by the stability of the rock. (2) The width of the stone is determined by the performance of the mining equipment, the specifications of the blocks and the cracks, and is generally 1~3m. (3) The length of the working face is generally 5~15m for artificial mining; the mining of flame cutting machine is generally 15~20m. Minimum working platform width: generally 20~25m. Generally speaking, the current mining work in the mine is mainly in the semi-mechanical and semi-manual mining state, and has not yet formed a certain scale. There is still a lack of uniformity and systemic management.
The Mask Machine is a multi-layer non-woven fabric made by hot
pressing, folding forming, ultrasonic welding, scrap removal, ear strap bridge
welding and other processes to produce various masks with certain filtering
performance. The mask equipment is not a single machine, it requires
Coordination of multiple machines to complete various processes.
N95 Mask Machine Production Equipment,N95 Face Mask Machine,N95 Facial Mask Making Machine,N95 Face Mask Forming Making Machine Borong Machinery Manufacturing CO. LTD , https://www.boronjx.com
Granite mining steps and technical requirements
First, granite mining is generally divided into the following steps: