Environmental LCA and rational development order concerning resources development

利用原USBM发布的《采矿成本估算数据库》，根据矿床所在地、采矿方法、生产规模等对采矿和加工过程中的设备和消耗品成本进行估算。开发了一个数据库应用程序，它根据每个矿井的能源和材料消耗量，根据各自的国内价格换算成本，计算出矿产品的单位二氧化碳排放量。根据日本冶炼厂主要铜和锌精矿供应商各自的单位二氧化碳排放量估计，估计了日本铜和锌冶炼的完整单位二氧化碳排放量。7个主要供应商生产的铜的加权平均单位二氧化碳排放量为2.063公斤-二氧化碳/公斤。由于国内铜产量的三分之二来自这7个矿山的精矿，国内铜的单位二氧化碳排放量约为2公斤-二氧化碳/公斤。关于锌，在九个主要精矿供应商中，只有四个矿场的数据可用。与铜相比，冶炼过程中单位二氧化碳排放量对锌的影响更大，因为即使是这四个矿中单位二氧化碳排放量最高的，如Mt.ISA仅占锌总单位CO_2排放量的一半。生产成本和单位CO_2排放量并不总是相互关联的，以至于在按30美分/公斤二氧化碳征收碳税的情况下，7个铜矿中的4个矿山的总成本几乎相等。事实表明，合理的开发顺序可能会随着碳税税率的变化而改变。

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.