Mine water refers to all types of water that flow into underground tunnels or open-pit mines during the mining process, and is considered an unconventional water source. It mainly originates from atmospheric precipitation, surface water, groundwater, fault water, and water from mined-out areas. Based on water quality characteristics and the types of main pollutants, mine water can generally be classified into the following five categories:
1. Clean Mine Water: This refers to mine water with extremely low suspended solids content, usually from aquifers drained separately for production safety. Its water quality is neutral, with very low turbidity and total salinity, basically meeting drinking water standards. After disinfection, it can be directly used for industrial and agricultural purposes.
2. Mine Water Containing Suspended Solids: This type of mine water is mainly polluted by suspended solids (such as coal dust and rock dust). The pH value is usually neutral, and the appearance is often grayish-black. The suspended solids content varies greatly; the particles are fine, low in density, and settle slowly, making treatment more difficult. This type of mine water accounts for the largest proportion of the total, approximately 80% or more.
3. High-salinity mine water (high-mineralization mine water): This refers to mine water with a salt content exceeding 1000 mg/L. Major ions include K+, Ca2+, Na*, Mg2+, Cl, SO42-, etc. Its total salt content is generally between 1000 and 10000 mg/L, with some mining areas exceeding 10000 mg/L, requiring desalination processes such as reverse osmosis and membrane concentration.
4. Acidic mine water: This refers to mine water with a pH value below 6.0, generally between 3 and 5.5, with high total acidity. Based on the heavy metal content, it can be divided into general acidic mine water, high-iron-manganese acidic mine water (total iron > 6.0 mg/L, total manganese > 4.0 mg/L), and acidic mine water containing other heavy metals. This type of water requires neutralization pretreatment.
5. Mine water containing special pollutants: This refers to water with excessive levels of fluoride, iron, manganese, copper, zinc, lead, and trace elements or radioactive elements such as uranium and radium. This type of water requires targeted treatment technologies based on the specific pollutants, such as adsorption, ion exchange, or special precipitation processes. Examples include high-iron and manganese mine water, high-turbidity mine water, and high-mineralization mine water.
