El Boleoとは 意味・読み方・使い方

El Boleo was a Mexican copper mine located at the port city of Santa Rosalía, Baja California Sur. It was operated by a French company (Compagnie du Boleo) who had obtained control of the mine through an extensive concession and 50-year tax extemption granted by Mexican president Porfirio Diaz who apparently had the idea it would create a development pole for that arid and depopulated region. The discovery of the copper ore is historically credited to a rancher named José Rosas Villavicencio in 1868. Although minor mining works were carried out on site by Mexican and German operators, the real large-scale mining and metallurgical processing did not start until 1885 by the abovementioned company, which is also considered the official date of the town foundation. As the ore was extremely rich (Apparently a complex mixture of oxides and sufides of up to 15% Cu) it could be fed directly to the smelter without pre-processing other than crushing. There were 7 relatively small reverberatory furnaces in the smelter and somewhere around the 1930s a pair of Peirce Smith Metallurgical Converter were added to produce blister copper (98% copper). The French company operated until 1954 when the tax payment exemption expired and was shut down due to bankruptcy. Then the Mexican government through its Mining bureau (Namely the Comisión de Fomento Minero) reopened the works under the name of CMSRSA (Compañía Minera Santa Rosalía) to avoid collapsing of the town. It operated continually on losses using the same (rather archaic) process until 1984 when it definitively closed. It is suspected that huge amounts of low grade ore still exist on the site, however the old metallurgical process used is unfit for the recovery of these values, and besides, the lack of fresh water makes very difficult the commissioning of a hydrometallurgical process, which would be the soundest option.