The Use of Limited Field Observation in Remedial Design

As a consequence of a slope failure, an investigation was carried out to determine the present and future stability of a gold tailings dam in the Orange Free State, South Africa. Recommendations were also required concerning the type of remedial measure(s) necessary in order to permit continued deposition of the tailings waste product on the dam. The field and laboratory investigation involved sampling of the tailings and foundation soils and installation of piezometers at various locations around the dam. The paper describes how, using data obtained from a limited monitoring period, evaluation of in-situ parameters enabled prediction of future phreatic surface variations under differing operating and climatic conditions