Effective Ranges of a Modeled Open Limestone Channel

Acid mine drainage (AMD) is the outflow of acidic water from metal mines or coal mines. When exposed to air and water, metal sulfides from the deposits of the mines are oxidized and produce acid, metal ions and sulfate, which lower the pH value of the water. An open limestone channel (OLC) is a passive and low cost way to neutralize AMD. A mathematical model has been created to numerically determine the change in pH of the water and the concentrations of species from the dissolution of calcium on the surface of the limestone into the acidic water. The model is used to predict the conditions in which a OLC would be an effective solution for AMD. Effective ranges are determined for the concentrations of calcium and iron, as well as the temperature and velocity of the water.