Mine filling system

(1) Filling process

1. Conveying method of filling materials

(1) hydraulic transmission. At the surface filling preparation station, the water-sand filling material or cemented filling material is sent to the underground stope for filling through the filling pipeline by means of double line dead weight transportation, or by pump.

(2) Wind transport. Generally, filling stations are set up underground to prepare cemented filling or dry filling materials, and then compressed gas is injected into stope through pipelines for filling.

(3) Mechanical filling. Dry filling materials are often filled through the filling well and then transferred to the stope, where they are filled by electric harrows or throwers. Filling is made of concrete or through surface mixing, vertical pipe down the well, or in the underground preparation station, and then sent to the stope, and then filled with electric harrow or thrower.

At present, hydraulic filling is the main method at home and abroad. Whether it is wind filling or mechanical filling, there are auxiliary transport filling problems, many links, more complicated technology. But the wind filling machine and the thrower filling machine have the advantages of high filling density and good top connection. Some mining methods, such as upward and downward filling methods, can fully show their superiority.

2. Hydraulic filling process

1) Determination of fluid type

From the perspective of rheology, hydraulic transport can be divided into heterogeneous flow of Newtonian flow and homogeneous flow of non-Newtonian flow. In the homogeneous flow of non-Newtonian flow, Bingham flow, pseudo plastic flow, yield pseudo plastic flow and time dependent energy variable flow are often seen.

Under certain conditions of conveying material (weight, particle size), concentration is the main factor that determines whether the slurry belongs to the heterogeneous flow of Newtonian flow or the homogeneous flow of non-Newtonian flow.

2) Conveying Newton flow heterogeneous flow fillers

At present, most of the hydraulic conveying water-sand filling materials and cemented filling materials in China's mines are heterogeneous flows. When the tailing is filled, the weight of the tailing is 2.7g/cm³, and the weight concentration is less than 67% ~ 69% (depending on the size gradation). The water-sand filling of coarse sand is all heterogeneous flow. This kind of low-concentration heterogeneous flow transporting water-sand filling requires better permeability coefficient of fillers and good dewatering facilities installed in stope to make it dehydrated in time.

Because of its high water content, cement segregation is easy to occur and the strength of filling body is low when the cemented filling material is transported with heterogeneous flow. Stope dehydration is dominated by overflow. In order to reduce horizontal cement segregation, the filling hose in the stope is moved as quickly as possible during the filling process.

Conveying heterogeneous flow filler, its water content is large, in the water out, often contains more fine-grained solid materials, need to precipitate treatment in time, should try not to make it into the water tank. It is recommended to set up a sedimentation tank in the mining area in the stage, and the solid materials can be cleared in time after settling in the sedimentation tank, and the water can be cleared into the water tank.

3) Conveying non-Newtonian flow homogeneous flow fillers

When the concentration of conveying slurry is increased to a certain extent, homogeneous flow is formed, and homogeneous flow is mainly used for conveying tailing filler, tailing cemented filler and fine sand cemented filler. Its advantage is that it can prevent pipe clogging, reduce pipe wear and reduce underground drainage and pollution. For cemented fillers, the more important advantage is that the strength of the filling body can be greatly improved.

3. Full tailings filling process

The tailings filling in China are all settled sand, and the amount of settled sand is often insufficient. Overflow tailings can not be dammed, need quarrying dam construction, high cost, fine grained overflow tailings will cause pollution to the environment. All tailings filling can avoid and improve the above problems. The difficulty of full tailing filling lies in the settlement and dehydration of fine-grained tailing, and the ideal condition is to make a homogeneous flow with high concentration on the surface and transport it to the mine instead of dewatering the mine. At present, it is mainly used for subsequent filling of goaf.

4. Cemented stone filling process

In this process, after returning to the mining room by the open stope method, the block is filled with stone, and then the cement mortar is injected into the block stone to form block concrete. Or the gravel is poured into the goaf at the same time, the cement mortar is transported by the pipeline to form a block of stone concrete, and then the pillar mining.

(2) Filling system

The mine filling system is a process system in which solid mine waste is used as aggregate, cement and other materials are used as cementing materials, and a certain concentration of filling slurry is prepared by concentrating and stirring, and then transported to the underground stope for filling by means of arteflow or pumping. At present, the common filling aggregate in mines is tailings, and crushed waste stone, Gobi aggregate and other coarse aggregates are also used. The coarse aggregate is transported to the mixing system through the conveyor belt during the mixing stage. The process is relatively simple, so it is not explained in detail. The tailings filling system is mainly introduced here. The tailings filling system is mainly composed of tailings concentration and storage system, cementitious material storage and feeding system, filling slurry mixing system, filling slurry conveying system and automatic filling control system.