During an earlier program a process for the treatment of coal mine drainage was conceived, involving the combined addition of limestone and hydrogen sulfide to effect precipitation of iron sulfides (LHS process). The black sludge formed during treatment undergoes oxidation at a rate depending on drying conditions with formation of elemental sulfur. X-ray diffraction analyses indicate the iron sulfide sludge component is an amorphous material. The unstable nature of the sulfide sludge, possibility of polysulfide formation during treatment, instability of mine waters of the type amenable to treatment, and inadequacies of available gas metering equipment are among the factors which militate against the controlled regulation of hydrogen sulfide feed necessary for successful operation of the process. These factors, and additional disadvantages revealed by an updated cost evaluation, lead to the conclusion that the LHS process is less attractive than accepted methods of mine drainage treatment. (Author)

"Program number FWPCA Grant no. 14010 DLC." Includes bibliographical references (pages 61-65). Microfiche.