序言在美国强调采用大型设备和较少的系列建设大型的选矿厂。因此,以处理每吨矿石为基础而言所占厂房面积较小;投资低;操作人员少;维护费低和效率较高。在经济上有利时采用自动控制。老厂和新厂都在进行环境保护的改善。不经过冶炼厂和炼铁高炉的新方法正在发展。正在进行就地浸出的研究。至少有一个工业性的装置将于明年投入生产。 The Preamble in the United States emphasizes the use of large equipment and fewer series of large-scale concentrators. As a result, the plant area is small on a per-ton basis, with low investment, fewer operators, lower maintenance costs and higher efficiency. Use of automatic control when economically beneficial. Old factories and new factories are improving the environment. New approaches that do not go through smelters and blast furnaces are evolving. Research is ongoing in situ leaching. At least one industrial plant will go into production next year.