Abstract
Alternative tailings disposal methods such as dry stack are often neglected as optimal mine waste disposal methods due to perceived high cost. However, transitioning from traditional wet tailings to dry stack and alternative tailings disposal is critical for decreasing freshwater consumption and de-risking projects. A critical step towards dry stack and alternative tailings disposal is the installation of equipment packages that can optimize water management, such as optimized thickeners, hydro-cyclones and filter presses. Building a business case for improved water use and tailings management requires concurrently building business cases for installing these equipment packages.
This research presents an open-source tailings economic trade-off (TET) techno-economic model to allow a comparison of water use and cost between different tailings disposal-related equipment choices, addressing a significant gap in models available for operators and early technology decision-makers. The model's utility is illustrated through a case study of a hypothetical Chilean copper mine based on blended real data. The open-source tool focuses on modelling core techno-economic variables. These variables encompass the capital costs and operating costs, the performance of vendor-supplied equipment packages modeled against the size distribution of tails, desalinated water cost, the cost of traditional tailings dams, and how those variables impact the value of optimizing a reduction in wet tails and water recovery on a desktop basis. The findings indicate a substantial technical and economic return through implementing a thickener control system and hydro-cyclone compared to the costs of accessing desalinated water pumped from the coast. The application of the TET model to the hypothetical Chilean found that all three equipment packages delivered recovered water on a total economic basis for a fraction of the cost of desalination and pumping. Furthermore, there is an economic incentive associated with changing the mining industry's approach to not just focus on the capital cost of projects but to look at the value of changing the mine waste process. Early-stage economic modeling can quickly develop a business case for new water and energy-saving technologies, including technical, ESG, and financial return factors.