A structured approach to co-disposal program development: standardising methodologies for efficient and cost-effective mine waste management

Co-disposal involves the storage of tailings and mine waste rock together in a single facility. Mixing waste rock and tailings, called commingling, is a form of co-disposal that offers potential benefits over conventional mine waste storage methods, including a more efficient use of space at a mine site, increased geotechnical stability relative to tailings alone, improved seepage water quality relative to waste rock alone, water recovery, and others. In recent years, co-disposal technologies have received increased interest within the mining industry, with several mine owners committing to studies to evaluate co-disposal as a mine waste disposal technology for specific sites and for general application. However, a standardised methodology for evaluating and developing co-disposal – from concept through operational implementation – is currently lacking. Eagerness to ‘try it out’ – to implement field trials without setting objectives based on identified use cases – can lead to unmeasurable or inconclusive outcomes. This paper proposes a comprehensive methodology for developing and executing a tailings and waste rock co-disposal technology development program, including sequencing of project stages and gates within the project cycle. The focus is technical, with a multidisciplinary framework including process/dewatering, geotechnical and geochemical disciplines for testing campaigns at different scales correlated to project phase, illustrating the interactions between the testing programs. The proposed methodology provides a structured approach to co-disposal program development, ensuring that mine owners can make informed decisions to achieve efficient, cost-effective outcomes.