Controlling acid mine drainage from the Ficher Mining District, Oklahoma, United States

Abstract

The Picher Mining District, located principally in north-eastern Oklahoma, was one of the world's largest lead-zinc mining areas during its 55 year life. The field covers an area of approximately 72 square miles (186 km²); an estimated 1.22×10⁸ m³ of material worth in excess of one billion dollars, has been mined.

Mining activities were typified by surface exploratory drilling indentifying ore distribution and extension of underground workings to the lead and zinc deposits outlined. Exploration holes were either left unplugged or plugged at the surface with a section of a telephone pole. Low grade ore and waste rock were discarded in mined out portions of drifts. These waste piles containing pyrite and marcasite were left underground and oxidised during the many years of active mining. Upon cessation of mining activities in the mid-1960s, the drifts and shafts of the abandoned workings began to flood as the cone of depression filled in, leading to the dissolution of the oxidised sulfides and the formation of large volumes of acid mine water in the mined out openings. The resulting poor quality water, with high concentrations of cadmium, iron, lead and zinc, began discharging at the surface in 1979. Contamination of the underlying aquifer supplying local residents was first detected on a localised scale in 1980. The present surface water and groundwater contamination have lead to the area being classified as one of the top ten hazardous waste sites in the U.S. by the EPA under the superfund program.

To mitigate the current conditions we have proposed that acid mine water be collected where it currently discharges at identified springs and pumped from widely spaced wells in the workings. The water would then be treated at a 87.4 1/sec lime neutralisation/precipitation facility. Construction costs are estimated to be $3.7 million and $560,000/yr for 0 & M.