Predicting Water Content and Saturation in Mine Tailings with an Electromagnetic Soil Moisture Sensor

The degree of saturation of mine tailings plays an important role in the geotechnical and geochemical stability of a tailings facility and therefore, reliable measurements of in situ tailings saturation aid in evaluating stability. However, measuring in situ saturation in tailings facilities can be challenging. The objectives of this study were to evaluate the ability of an electromagnetic soil moisture sensor to predict the volumetric water content and degree of saturation of mine tailings and conduct proof-of-concept tests to assess the potential use of electromagnetic sensors as a tool in tailings engineering. Laboratory-scale testing was conducted using an electromagnetic soil moisture sensor embedded in moist-tamped and slurry-deposited specimens of a single hard rock mine tailings prepared at varying volumetric water content, degree of saturation, and dry density. Errors in predicted volumetric water content for proof-of-concept testing were less than 1.5% to 3.8% and the error in predicted saturation was mostly less than 5%. Based on this study, electromagnetic sensor technology offers a viable tool to predict the degree of saturation within tailings facilities and can be incorporated into innovative approaches to address the challenges encountered in different types of tailings facilities.