In the process of mine construction and production, due to the complex natural conditions, poor operating environment, and people's understanding of the objective laws of mine disasters is not comprehensive and in-depth enough, sometimes careless and illegal operations, illegal command, which caused the possibility of some disasters. In order to deal with mine accidents quickly and effectively, protect workers' life safety, and reduce national resources and property losses, the two Regulations must be followed（ Coal Mine Safety Regulations , coal mine rescue regulations). At the same time, it is also necessary to educate employees on how to actively carry out self rescue and mutual rescue in case of accidents. Mine rescue team is responsible for handling Mine fire The professional team for gas, coal dust, water, roof and other disasters is a professional and technical organization that strictly implements military management. Practice has proved that the mine rescue team has played an important role in preventing and handling mine disasters and accidents. Mine water mainly consists of surface seepage water, rock pore water, pit water, drainage water of underground aquifer, and underground production dust prevention, grouting, and filling sewage generated with the mining of the mine. Sewage from the concentrator and coal washing plant is the main source of mine wastewater. Generally, the pH value of mine water is between 7 and 8, which is weakly alkaline. However, the sulfur bearing mine water has more SO42 -, mostly acidic water. In sulfur bearing mines, sulfide minerals are contained in ores or surrounding rocks and sulfur bearing coals. These minerals are oxidized, decomposed and dissolved in mine water to form acid water. Especially in the mining roadway, under the conditions of massive infiltration of groundwater and good ventilation, it provides a very favorable environment for the oxidation and decomposition of sulfide minerals.
The sewage discharged from underground mining, especially hydraulic coal mining and water sand filling mining, cannot be ignored. According to statistics, if backwater utilization is not considered, wastewater discharge is about 1m3 for every 1t ore produced; About 0.5~10m3 of waste water is discharged from underground to produce 1t raw coal, and the maximum is 60m3. In addition, after some mines are closed, a large amount of wastewater will continue to pollute the environment of the mining area. Moreover, the impact of mine wastewater is far beyond the mining area itself.
Mine water pollution can be divided into mineral pollution, organic pollution and bacterial pollution. There are also radioactive material pollution and thermal pollution in some mines. Mineral pollution includes sand, mud particles, mineral impurities, dust, dissolved salts, acids and alkalis, etc; Organic pollution includes coal particles, oil, biological metabolites, wood and other substances. As well as being polluted by scattered powder ore, coal powder, rock powder and associated minerals during mining and transportation, the water body is gray black, turbid, with oil film floating on the water surface, and emits a small amount of fishy smell and oily smell. According to the water quality analysis and inspection results, the chemical oxygen consumption is high, and the total number of bacteria and coliform group are high. If untreated, they are allowed to be discharged for a long time, which will have some adverse effects on the environment.
Whether a substance will cause water pollution after being discharged into the water body mainly depends on the nature and concentration of the substance in the wastewater, the total discharge amount of the wastewater containing this substance, the characteristics of the polluted water body, and its capacity to absorb pollutants.
Main pollutants in mine wastewater:
（1） Organic pollutants 。 The plant decay in the mine wastewater pool and tailing pond may cause high organic content in the wastewater. The wastewater discharged from the concentrator, coal washing plant and analysis laboratory contains phenol, cresol, naphthol and other organic substances, which are extremely harmful to aquatic organisms. （2） oil and grease 。 Oil pollutants are relatively common pollutants in mines. Oily wastewater immerses into the pores to form oil film, which can block the soil structure, be harmful to the growth of plants, and even kill crops. The oil film on the water surface hinders the transfer of oxygen in the atmosphere to the water body, resulting in no oxygen in the water body and the death of aquatic organisms due to lack of oxygen. (3) Acid and alkali pollution. Acid and alkali pollution is a common phenomenon in water pollution. After the acid and alkali wastewater is discharged into the water body, it changes the pH value of the water body, inhibits the growth of bacteria and microorganisms, hinders the self purification of the water body, and can also corrode ships and hydraulic structures, and damage the normal ecological cycle.
(4) Cyanide. Cyanide is highly toxic. Generally, people will die if they take about 0.1g sodium cyanide or potassium cyanide by mistake. Sensitive people can be killed even by 0.06g. When the content of CN - in water reaches 0.3-0.5mg/L, the fish will die.
