Worldwide, it is estimated that there are an average of two tailings dam failures every year[i]. In Australia, the regulatory environment has made it extremely difficult to build a new dam. These are indications that current practice is not working to the level required. Not only can tailings storage work better, but it can also be done economically.
Modelling the lifetime costs and the financial risks of wet tailings storage is a challenging task. Variables include rainfall, evaporation, seismic activity, seepage, mine production rate, rheology, etc. just to name a few obvious ones. It becomes even more complicated and costly if you consider closure, rehabilitation, the unpredictability of developing regulations and the “social license to operate”.
Calculating the cost of a tailings dam failure is also a challenging task for many reasons. For a period, the Brazilian government pursued homicide charges against senior executives in the aftermath of the Samarco tailings disaster. Can you input “cost of homicide conviction of senior executives” into a financial risk model? This is an extreme example, but it highlights the social cost of such an event.
Storing tailings in a dry state eliminates these risks and there is a geosynthetic technology developed in the early 90s that efficiently facilitates dry tailings storage while offering many other benefits to a mining operation.
Geotube® Dewatering Units are large porous containers that are designed to efficiently retain solids and allow fluids to pass. The technology has been used worldwide to dewater and contain mine tailings safely and economically. (Here are some examples.) This solution improves risk, environmental impact and cost when compared to a traditional tailings dam.
Improved Environmental Impact
At the Geofabrics lab in Gold Coast, Queensland, our team tests tailings slurry samples to evaluate and optimize dewatering options. Prior to lab testing, we can advise on the suitability and scale of a Geotube® solution based on some basic inputs such as slurry volume and solids concentration.
For more information, contact the author or your local Geofabrics branch.
[i] Williams, David. Future Tailings Management. Tailings 2017. 4th International Seminar on Tailings Management. (2017)