"Under the current situation of slow recovery of global economy and deep adjustment of China's economic structure, both the world and China's mining industry have entered a relatively difficult period. It is the only way to vitalize the metal mining industry to develop advanced and unconventional new mining theories and technologies -- Cai Meifeng, academician of the Chinese Academy of engineering.

Open stoping, caving and filling are three common mining methods in metal mines. Because of its high cost, filling method is only used in some mines with high mineral value.

In order to adapt to the requirements of green mining, reduce the environmental pollution caused by mining and damage to the ecological environment, it is necessary to fundamentally change the traditional mining mode and technology.

1、 Change of mining technology

1. Mechanical continuous cutting and driving technology

From the long-term goal, it is an important direction to replace the traditional blasting mining technology with continuous cutting equipment by adopting the methods of mechanical driving and mechanical drilling. Because the blasting mining technology causes damage to the stability of surrounding rock, and the ore and waste rock are mined together, which greatly increases the workload of beneficiation and upgrading.

advantage

1 & gt; mechanical cutting can accurately mine the target ore and reduce the ore dilution rate to Zui low.

2 & gt; can realize parallel and continuous cutting, loading and transportation process, which creates conditions for continuous mining.

problem

1 & gt; the operation of mining machine is influenced by the variety of metal deposit forms

2 & gt; complex geological conditions and life and cost of cutting head

2. High pressure water jet rock breaking driving and mining technology

High pressure water jet technology is a new cleaning and cutting technology developed in 1970s. At present, high-pressure water jet has been used to break soft rock and medium hard rock, which is widely used in coal mines. But when the hard rock is broken, higher water jet pressure is needed, which will reduce the reliability and life of the jet launcher system.

In order to solve the problem of hard rock breaking, high-pressure water jet needs to develop towards the direction of ultra-high pressure and high power. It can be used to break rock under the condition of hard rock.

3. Laser rock breaking driving and mining technology

Laser rock breaking is to use the heat generated by high-energy laser beam to heat the local rock rapidly. With the increase of temperature, the rock can be broken, decomposed, melted and vaporized in turn.

Mining rock can be broken as long as it is broken. When the high-energy laser acts on the rock surface, the local thermal expansion of the rock rapidly results in the increase of local thermal stress. When the thermal stress is higher than the ultimate strength of the rock, the rock will be hot broken, and the rock will be cut.

4. Plasma rock breaking driving and mining technology

This technology uses electric energy to change the electrolyte in the blast hole into high pressure and high temperature plasma gas, which expands rapidly to form shock wave and produces blasting effect similar to explosive. The pressure produced by blasting can exceed 2gpa, which is high enough to break hard rock. The implementation of this technology can greatly improve the working environment and reduce the impact and damage of traditional blasting on surrounding rock and environment.

2、 Support technology change

5. Paste filling mining technology

Generally, because of the high cost, only some mines with high mineral value adopt filling method.

However, in order to realize green mining, control the movement of rock strata and surface subsidence, protect the natural and ecological environment, effectively control the intense ground pressure activities of deep mining, and avoid the occurrence of various disasters caused by the instability and damage of roadways and stopes, the filling mining method will be the mining method that most mines, including iron mines, have to choose. This is a major change in the traditional mining model.

However, the principle of balancing mining value and support cost should be abided by. In order to reduce the cost of filling, it is necessary to reform the filling technology and materials. Full tailings paste filling can obtain high quality filling body under the condition of low cement consumption, effectively maintain the empty area and control rock burst. It represents the development direction of this technology.

3、 Reform of integration of mining and beneficiation

6. Mining and separation integration technology

Downhole pre selection and tail throwing technology. Before the ore is lifted to the surface, the ore lifting capacity can be significantly reduced by pre concentration and pre concentration in the underground and discarding most of the waste rocks.

Pulp conveying technology. For deep mining, it is a potential technology to crush and grind the ore into slurry after pre concentration, and then send it to the surface concentrator by pipeline transportation. Compared with other transportation schemes, pipeline hydraulic transportation has a series of advantages, such as low capital construction investment, strong adaptability to terrain, no or less land occupation, little interference of continuous operation by external conditions, high degree of automation and reliable technology.

The concentrator will be built underground. It is an important way to solve the lifting problem that concentrate is directly transported to the ground after underground beneficiation, which can greatly reduce the lifting amount of waste rock. At the same time, it is an important method to keep the waste rock and tailings in the mine for filling the goaf, realizing the original use, and reducing the pollution and damage to the ecological environment after discharging from the ground. Moreover, there is no concentrator or and tailings pond on the ground, which saves the cost of land acquisition and tailings pond management, and plays a role of more than one stroke.

4、 Mining technology change

7. No waste mining technology

The goal of no waste mining is to reduce the output and discharge of waste materials to a large extent, improve the comprehensive utilization rate of resources, and reduce or eliminate the negative impact of mineral resources development.

Therefore, mining activities should follow the view of industrial ecology, link the ecological environment, resource environment and economic environment of the mine, obtain the large resources and economic benefits of Zui with the small emissions of Zui, and fully protect the ecological environment.

In order to realize waste free mining, first of all, mining method with small mining cut ratio should be adopted, ore dilution rate should be greatly reduced, Zui of waste output should be minimized, and waste rock output rate should be controlled from the source.

At the same time, it is necessary to improve the level of beneficiation technology, improve the recovery rate of beneficiation, the comprehensive utilization degree and utilization rate of resources as much as possible, and reduce the discharge of tailings; develop innovative beneficiation technology and equipment, and reduce the unusable components of ore resources due to the low level of beneficiation and metallurgy to Zui.

Through the methods of underground pre concentration and setting the concentrator under the well, the waste rock and tailings can not be discharged from the well, which can be used to backfill the goaf and realize the on-site and effective utilization of the waste from mining and separation.

Strengthen the comprehensive recovery, realize the recycling of waste, improve the overall utilization level of waste, and strive to achieve zero discharge and zero storage of solid waste in mines.