The main components of the mineral water are suspended matter and soluble inorganic matter, and the suspended matter SS is mainly composed of coal powder and rock powder, and its content is unstable. In addition, when the mine water flow passes through the coal face and roadway, it is affected by human beings, and some organic matter is mixed into the water. The main component of SS in the mine water is pulverized coal, which can be oxidized by strong oxidants such as potassium dichromate, so it shows a relatively high CODcr.