The geotechnical aspects of a hazardous waste disposal site located in Piney River, Nelson County, Virginia, were investigated. The waste material consisted primarily of a by-product of the production of titanium known as copperas which is highly acidic. The investigatory program consisted of field and laboratory work. Objectives included delineating the pit geometry and liner system, assessing the characteristics of the natural soils at the site as well as the wastes, and evaluating the degree of contamination of the natural subsoils around the pit. The field investigation findings show a more complex geometry for the pit than that suggested in the design documents. While shown on the plans, the presence of the bottom clay liner is questionable. Large depressions and numerous cracks were found in the waste area. Acid contamination of the groundwater and the subsoils exists to a considerable depth. Laboratory tests illustrated the susceptibility of the copperas to dissolution under water seepage. This could have caused the large settlements. Remedial actions could include grading the top of the pit for better drainage. Other actions could include redepositing the waste in a burial pit which has a leachate collection system and properly compacted clay liners which include an impervious fabric. Perhaps the waste could be treated chemically prior to final disposition. In any case, some level of continual maintenance will be necessary. / M. S.