基于生态足迹方法,构建了反映金属矿床露天开采的生态压力的直接和间接生态足迹模型,前者度量露天开采对生态系统的直接损害;后者度量其能耗产生的CO2排放对生态系统的间接冲击。基于生态足迹和生态系统的主要生态服务功能,建立了露天开采的生态成本估算模型,包括直接生态价值损失、外生生态价值损失、复垦成本和能耗生态成本。针对某露天矿的最终境界和生产计划,估算了其生态足迹、生态成本现值和矿山利润现值。该算例显示,总生态成本现值是不考虑生态成本时矿山利润现值的78%,不由矿山经营者负担的外生生态价值损失和能耗生态成本是利润的33%。可见,如果国家强制要求矿山经营者负担全部生态成本的话,露天矿山的投资回报将大幅下降,许多资源条件较差的矿床将不被开发,这对保护资源有积极作用。
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