It is evident that the systems usually used to monitor and control tailings facilities – primarily porewater pressure gauges and observation wells – do not represent the true conditions at the facility, due to the heterogeneous nature of the relevant deposits. Effective risk assessment and risk management should be based on additional information that can be used to determine when critical situations arise. Several observations on tailings facilities have shown a climatically induced alteration in the chemical and radiological parameters in the drain water. These parameters are therefore appropriate for use as stress indices. Systematic work on the correlations between changes in stress indices and the phreatic surface comprised some of the research undertaken by the Bauhaus University, Weimar, Germany. This article describes the principles of this type of monitoring and the soil mechanical background, as well as giving details of the equipment and results.