Ecological Footprint and Ecological Costs in Open-Pit Metal Mining
金属矿床露天开采的生态足迹和生态成本

Net present value (NPV) has been the main criterion in mining project evaluation and production plan optimization. It is common practice in NPV calculations to take into account only the tangible cost items in the corporate accounting system. The costs incurred due to damage to the local ecosystem and environment are treated as externalities and hence left out. Such practice on the one hand underestimates the total cost of a mining operation and, on the other hand, ignores the difference in ecological/environmental impacts between different mine plan alternatives. With growing interest in sustainable development, however, the mineral industry is under increasing pressure to operate mining operations not only based on economic and engineering principles but also in accordance with the principles of sustainability. The ecological costs of mining are estimated based on the areas and type of land (e.g. forest land, grazing land, crop land) damaged by mining activities and the carbon emissions from fossil fuel consumption. Based on the ecological footprint method, direct and indirect ecological footprint models have been developed to reflect the ecological pressure of open-pit metal mining. The former measures the direct damages of open-pit mining to the ecosystem, and the latter the indirect impact of CO2 emission from energy consumption on the ecosystem. Based on the ecological footprints and the major eco-service functions of the ecosystem, the ecological costs of open-pit mining are estimated, including lost value of direct eco-services, lost value of indirect eco-services, reclamation costs, and the eco-cost of energy consumption. The present values of ecological costs and profits were estimated based on the ultimate pit and mining schedule designed for a real open-pit mine. Results show that the total present value of ecological costs is 78% of the present value of profits, and the sum of the lost value of indirect eco-services and eco-cost of energy consumption, for which the mine operator is not responsible, is 33% of the present value of profits. It can be seen that, if mine operators were forced by the government to be responsible for all the ecological costs, the returns on investment in open-pit mines would be sharply lowered and many deposits with relatively unfavorable reserve conditions would not be exploited resulting in better resources protection.