Experience with capping of tailings storage facilities for decommissioning projects in Australia
Mine waste facility liner and cover systems
Red Earth Engineering
A 100 hectare Tailings Storage Facility in the Northern Territory recently reached full capacity and was scheduled for decommissioning. This paper presents an overview of the design and construction challenges to implement a capping system on soft, contaminated tailings to enable diversion of runoff back to the environment. The project included installation of over 1 million m2 of geomembrane and over 2 million m3 of earthworks. Key aspects discussed include the cover design and barrier system to encapsulate the tailings, designing for a service life of 200 to 1,000 years, water management in a region that receives regular cyclonic rainfalls, construction on soft tailings, vegetation selection and agronomy of the available capping soils and the HSE challenges in working on soft, contaminated tailings.
Some lessons learned from the project that are being rolled out to the next TSF scheduled for decommissioned are also discussed.