How to mine black granite

one,black graniteMine excavation is generally divided into the following processes:

For the excavation of black granite mines, we must first select the mining area according to the resource conditions and market demand, determine the excavation realm, mine production planning, mine work system, etc. Mine excavation shall be carried out on the basis of comprehensive analysis of natural environment and economic and technical conditions. The mining process It can be divided into development and transportation, stripping and mining.

1. Development of delivery and loading

The mission of development and transportation is to open up the transportation path from the mining industrial site to the various working steps in the stope and the transportation path to the waste rock yard. The common development and transportation methods for granite open-pit mines are:

1) Road car transportation, this method is flexible and flexible, can give full play to the power of the loading equipment, and is a widely used method.

2) There is no ditch to open the mast crane for hoisting. This method does not need to excavate the transport channel from the surface to the excavation step, but is directly loaded into the transport equipment by the mast crane. This method has a small amount of engineering and low investment, but is limited by the capacity of the mast crane. And the constraints of the scope of work, the flexibility is poor.

In addition, there are also ways to open up trolley transportation for slope winch lanes, and jointly develop and transport road cars and mast cranes.

There are two types of loading equipment for loading the blocks onto the conveying equipment: fixed type and mobile type. Mast cranes are fixed type, such equipment has a large lifting height and a large lifting weight, and has both loading and transporting functions; crawler cranes and Wheel-mounted cranes are mobile loading equipment. This type of equipment is mobile and flexible, but the lifting height and lifting weight are small, so they are not suitable for the loading of large-sized blocks. The transportation of mine waste rock is usually carried out by manual carts, front loader, bulldozer, and crane. , cars and other equipment.

2. Block excavation is roughly divided into the following steps:

(1) Cap layer stripping: It is a process of stripping the floating soil and non-mineral rock layers covering the ore to facilitate the excavation of the ore. At present, the method of manual stripping is mostly used in mines, and only some mining sites use bulldozers and wheel loaders. Wait for mechanical peeling.

(2) Separation: It is the second process of separating the bar-shaped blocks from the original rock of the ore layer. Limited to the existing excavation planning and production methods, the mining waste basically adopts two methods: artificial chisel splitting and controlled explosion. Manual splitting The splitting method is based on the traditional manual drilling and wedging techniques. This method is relatively labor-intensive and low-power, but has a high yield rate and is easy to shape. Small pill roll to control explosion.

(3) Overturning: It is to overturn the strips of stones to facilitate cutting and separating them. There are various tools for overturning, such as manual jacks, hydraulic capping machines, push air bags and traction methods. Now they are mainly used in mines. The jack-and-pull method.

⑷ Disintegration cutting: It is to cut the strips of block stones according to the required design. The method of disintegration and cutting is roughly similar to the separation method. The main methods are manual wedging, chisel splitting and control explosion. .

⑸Shaping: Shaping is to make the cut block blanks into product blocks that fit the design through certain processing. Shaping methods include manual hammering, small hand-held drilling rigs, hand-held rock drills, and beaded diamond wire saws and shaping Machines, etc. At present, the methods used in mines are mainly simple methods such as manual hammering and chiseling, without mechanical operation.

⑹ Hoisting and loading: It is a process of transporting the processed blocks to the conveying tools. The tools used for hoisting can be various. Mine now mostly use mast cranes, and a few mining sites use car cranes, loaders and crawler cranes, etc. .

⑺Clearing: It is the process of transporting the crushed stone that is not a block out of the block processing plant.

2, Skill requirements for granite mining

Under normal conditions, when the production stripping ratio is about 0.3, the economic block rate of granite mines is 15%-25%.

(1) When a mobile crane is selected for the bench height in the mining field, the bench height is 4-6m; for small mast cranes, the bench height is less than or equal to 14m; for large mast cranes, the bench height is less than or equal to 62m.

The slope angle of the steps is generally 90 degrees, and the slope angle is determined according to the stability of the rock.

(2) The width of the strip is determined by the function of the excavation equipment, the size of the block and the condition of the crack, generally 1-3m.

(3) The length of the working face is generally 5-15m for manual excavation; the excavation for flame cutting machine is generally 15-20m.

Working channel width: generally 20-25m.

On the whole, the current mining operations of mines are mainly in the state of semi-mechanical and semi-manual excavation, which has not yet formed a certain plan, and the management still lacks unity and systematization.