Natural capital optimization of carbon, water, and tailings in mining and metals

Mining and processing metals present significant environmental and economic challenges as they deplete and convert natural capital, including carbon emissions, local water depletion, and tailings deposition, into metal production. This thesis aims to make a practical contribution to the mining industry by providing and documenting three techno-economic models that help price and optimize natural capital options around carbon emissions, wet tailings dam costing, and valuing the water recovery from the dry stack, thickener control systems, and hydro-cyclones. These tools help engineers, financial stakeholders, and outside stakeholders to improve decision-making. First, the research examined why a carbon tax would increase renewable energy production, resulting in a material increase in the demand for many minerals and metals. A financial model created to calculate the cost of carbon taxes for 23 commodities across three industries shows that, given any level of carbon taxation tested, excluding coal, mining has a regressive tax load in carbon taxation compared to the other commodities modeled. Second, the thesis introduces and tests a present-value USD/DMT financial costing model for traditional tailings storage facilities (TSF), focusing on improving early-stage decision-making on tailings disposal technology. The model provides a comparable metric for other tailings disposal options to be tested against, integrating capital, operating, and closure costs on a single present value metric. Finally, the thesis develops a techno-economic trade-off model (TET) to compare tailings technologies, including thickener control systems, hydro-cyclones, and dry stack tailings, against traditional TSF on a techno-economic basis. The results suggest that by including the value of the water recovered, all technologies are economically viable in Chile compared to traditional TSF. The model also shows that far more economic benefits are possible per water unit, reducing the carbon and capital footprint per tonne of metal produced from desalination and pumping. By bridging the siloed worlds of sustainability, engineering, and economics, this research contributes to better decision-making earlier in the development cycle of projects by policymakers, mining companies, and their engineering and equipment vendors. It also helps align industry economic incentives with environmental goals.