Classification of mines

Mine dust

Production dust is the main harmful factor of underground mine. Many production processes and processes, such as drilling, shooting, mining, rock loading, transportation, etc., can produce a large amount of dust. Workers for a long time to absorb this kind of dust, can occur silicon lung, coal lung or mixed pneumoconiosis. At present, 70% of the world's pneumoconiosis patients are in China, and the number of mine pneumoconiosis deaths in China exceeds the number of work-related deaths. The dust concentration in the mine is high, and the dust concentration qualification rate of the underground mine is only 40%-60%, and the open pit mine is only 70%-80%. With the decrease of mining depth, the comprehensive hazards such as air pollution in deep concave open pit should be paid attention to.

Toxic and harmful gases from mines

Methane is often present in mine air, and its main component is methane. There are also harmful gases such as carbon monoxide, nitrogen oxides and hydrogen sulfide. Methane is a colorless odorless flammable gas with a density of O.559kg/m3. Methane mainly comes from coal seam, coal block and rock wall. Methane can be mixed with air to form an explosive gas, which can explode in the event of an open flame. Methane explodes at concentrations ranging from 5% to 16%. An important source of carbon monoxide and nitrogen oxides is the smoke produced by blasting. The use of nitroglycerin explosives can produce a large amount of carbon monoxide, while the use of ammonium nitrate explosives often produce a large amount of nitrogen oxides. In a poorly ventilated mine, smoke poisoning may occur due to smoke accumulation after blasting.

Mine noise and vibration

Noise is one of the hazards that pollute the mine environment, and the underground operators suffer more from it. In recent years, the use of many large, efficient and high-power equipment has reduced labor intensity and improved production efficiency at the same time, resulting in more and more serious noise pollution. In particular, the underground equipment has the characteristics of multiple sound sources, continuous noise, high sound level and high and medium frequency noise spectrum. In addition, the underground working face is narrow and the reflecting surface is large to form a mixed sound field, and the noise can only propagate along the extension direction of the roadway, which is more harmful to the operators. Noise and vibration in mines are mainly generated during drilling, mining and transportation. In general, the noise and vibration of pneumatic tools are more serious than those of power tools and vibrating conveyors than belt conveyors. The labor intensity of miners is large, such as human tooling rock is heavy physical labor; Drilling and pushing are moderately manual labor. When working in thin layers, workers must not take bad positions such as squatting and stoop crawling throughout the working day.

Mine blasting safety

Blasting safety plays an important role in mine production. Blasting safety problems can be summarized into the following three categories: safety accidents caused by mechanical effects of blasting (such as seismic waves, shock waves, noise and individual flying rocks); Due to the physical and chemical reaction of explosive explosion, that is, a large number of toxic gases and electromagnetic effects caused by explosive explosion; Sudden accidents caused by blasting, such as early detonation of explosives, failure to detonate and safety accidents caused by operational errors. The accidents of personal injury and equipment damage caused by mine blasting occupy a large proportion in the whole mine accidents. With the development of mining industry, open pit blasting is very close to the industrial site of the mine itself, and there are also nearby towns and residential areas; Deep hole blasting and engineering blasting with large charge amount in underground mining are increasing day by day. The high temperature zone formed by mineral and rock material causes explosive self-detonation, early detonation, and smoke poisoning accidents often occur. The most typical is June 22, 2002, Shanxi Province Fanshi County Yixingzhai gold mine explosion accident, at least 37 miners were killed. Therefore, how to control the harmful effects of blasting and how to take protective measures is a problem that mines generally pay attention to. Safety accidents are no small things, especially the mining industry, only usually pay attention to this small aspects, in order to extinguish the accident in the bud!