Geochemical modeling of coal mine drainage, Summit County, Ohio

 Geochemical modeling was used to investigate downstream changes in coal mine drainage at Silver Creek Metro-park, Summit County, Ohio. A simple mixing model identified the components that are undergoing conservative transport (Cl^–, PO₄ ^3–, Ca²⁺, K⁺, Mg²⁺ and Na⁺) and those undergoing reactive transport (DO, HCO₃ ^–, SO₄ ^2–, Fe²⁺, Mn²⁺ and Si). Fe²⁺ is removed by precipitation of amorphous iron-hydroxide. Mn²⁺ are removed along with Fe²⁺ by adsorption onto surfaces of iron-hydroxides. DO increases downstream due to absorption from the atmosphere. The HCO₃ ^– concentration increases downstream as a result of oxidation of organic material. The rate of Fe²⁺ removal from the mine drainage was estimated from the linear relationship between Fe⁺² concentration and downstream distance to be 0.126 mg/s. Results of this study can be used to improve the design of aerobic wetlands used to treat acid mine drainage. Received: 4 June 1996 · Accepted: 17 September 1996