英和和英

出典:『Wikipedia』 (2011/03/21 21:47 UTC 版)

英語による解説

引用

Chat is a term for fragments of siliceous rock, limestone, and dolomite waste rejected in the lead-zinc milling operations that accompanied lead-zinc mining in the first half of the 20th century. Historic lead and zinc mining in the Midwestern United States was centered in two major areas: the Tri-State area covering more than 2,500 square miles (6,500 km²) in southwestern Missouri, southeastern Kansas, and northeastern Oklahoma and the Old Lead Belt covering about 110 square miles (280 km²) in southeastern Missouri. The first recorded mining occurred in the Old Lead Belt in about 1742. The production increased significantly in both the Tri-state area and the Old Lead Belt during the mid-19th century and lasted up to 1970.