Environmental LCA and rational development order concerning resources development

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Costs of equipment and consumables in both mining and processing process are estimated according to location of deposit, mining method, production scale, etc. using Mining Cost Estimation Database issued by former USBM. A database application is developed, which calculates an unit CO_2 emission of a mine product, based on consumed amount of energy and materials in each mine, estimated by converting the costs according to the respective domestic prices. Complete unit CO_2 emissions for copper, and zinc smelted in Japan are estimated, based on respective unit CO_2 emissions, estimated for major copper and zinc concentrates suppliers for Japanese smelters. The weighted average unit CO_2 emission of copper produced by seven major suppliers was 2.063kg-CO_2/kg. As two third of domestic copper production comes from, the concentrates of these seven mines, the unit CO_2 emission of domestic copper should be approximately 2 kg-CO_2/kg. Concerning zinc, data for only four mines out of nine major concentrates suppliers was available. Unit CO_2 emission from the smelting process plays more important role for zinc compared to copper, because even the highest unit CO_2 emission among these four mines e.g. that of Mt. Isa, only consists one half of the total unit CO_2 emission of zinc. Production costs and unit CO_2 emissions are not always correlating each other so that total costs of four mines out of the seven copper mines become almost equal under imposition of carbon tax at the rate of 30cents/kg CO_2. The fact indicates that the rational order of development, could change according to the rate of carbon tax.