The first mining area should be selected according to the resource conditions and market demand, and the mining boundary, mine production scale and mine working system should be determined. On the basis of comprehensive analysis of natural environment and economic and technical conditions, mine mining is carried out. The mining process can be divided into development, transportation, stripping and mining.
1. Develop transportation and loading.
The task of developing transportation is to open the transportation channel between the mining industrial site and the working steps in the mining site and the transportation channel leading to the waste rock site. The common modes of development and transportation in granite open-pit mines are:
1) Highway develops automobile transportation, which is flexible and can give full play to the efficiency of loading equipment and is widely used.
2) The trenchless development of hoisting in mast crane. This method does not need to dig the transportation passage from the surface to the mining steps, but directly loads the transportation equipment by mast crane. This method has small engineering quantity and low investment, but it is limited by the capacity and working range of mast crane and has poor flexibility.
In addition, there are ways to develop trolley transportation on sloping roads, and to jointly develop transportation between road vehicles and mast cranes.
There are two kinds of loading equipment for loading waste into transportation equipment: fixed and mobile. Mast crane is fixed, and this kind of equipment has large lifting height and heavy lifting weight, and has both loading and transportation functions; Crawler crane and tire crane are mobile loading equipment, which are flexible, but the lifting height and weight are small, so they are not suitable for loading large wastes. Manual carts, front loaders, bulldozers, cranes, automobiles and other equipment are usually used to transport mine waste rocks.
2. Waste ore mining can be roughly divided into the following procedures:
(1) Covering stripping: it is a process of stripping the floating soil and non-mineral layer covered on the ore to facilitate ore mining. At present, most mines use manual stripping, and only some mine sites use bulldozers and wheel loaders to strip.
⑵ Separation: it is the second process of separating the strip-shaped block stone from the original rock in the seam. Limited by the existing mining scale and production mode, mine reclamation basically adopts two methods: manual drilling and fracturing and controlled blasting. Manual splitting method is manual splitting with traditional manual drilling and wedging. This method has relatively high labor intensity and low efficiency, but the rejection rate is high and it is easy to plastic. Controlled blasting method is to drill holes with hand-held pneumatic drill and control blasting with black powder or small cartridge.
⑶ Flip: Flip the strip stone for easy cutting and separation. There are many tipping tools, such as manual jack, hydraulic jack, airbag propulsion and traction. At present, jacks and traction methods are mainly used in mines.
(4) Disintegration and division: the lath is divided into coarse materials or coarse materials according to the required scale. The method of disintegration and division is similar to the separation method, which mainly adopts artificial wedging, chiseling and controlled blasting.
5. Shaping: Shaping is to form a finished product with a suitable scale from the cut blank through certain processing. The shaping methods include hand hammering, small hand-held drilling rig, hand-held rock drill, beaded diamond wire saw, shaper and so on. At present, the main mining methods are simple methods such as manual hammer chisel, without mechanical operation.
[6] Lifting and loading: it is the process of transporting the processed waste to the means of transport. Tools for hoisting can be varied. At present, mast crane is widely used in mines, and a few mining areas use truck cranes, loaders and crawler cranes. (7) Slag removal: it is the process of transporting non-waste gravel away from the waste processing plant.
Second, the technical requirements of granite mining
Generally, when the production stripping ratio is about 0.3, the lowest economic waste rate of granite ore is 15% ~ 25%.
(1) When the height of steps in the mine field adopts truck crane, the height of steps is 4 ~ 6m, and the height of steps is less than or equal to14m; ; Large mast crane with step height less than or equal to 62m. The slope angle of steps is generally 90, and the final slope angle is determined according to the stability of rocks.
(2) The width of bar stone is determined according to the performance of mining equipment, specifications of raw materials and fracture conditions, and is generally 1 ~ 3m.
(3) The length of artificial mining face is generally 5 ~15m; Flame cutting machine mining is generally 15 ~ 20m. Minimum working platform width: generally 20 ~ 25m.
Generally speaking, the current mine reclamation work is mainly in the state of semi-mechanical and semi-manual mining, which has not yet formed a certain scale and lacks unity and systematicness in management.