Ferrograde Concentrates From Arkansas Manganiferous Limestone

Normally the U. S. produces less than 10 pct of its annual manganese requirement. About 95 pct of domestic consumption is used by the steel industry.1 The strategic and critical nature of manganese has been recognized by its inclusion in the national stockpile and by intensified research directed toward cataloging and evaluating domestic manganiferous deposits. The USBM has participated in these activities for many years with field and laboratory studies to assess the extent and potential utilization of domestic manganese ores. One area of particular interest is in the vinicity of Batesville, Ark., where deposits have been mined since 1849 for both manganese and ferruginous manganese ores. Production is centered in Independence County, but deposits are also found in Sharp, Izard, and Stone counties in north- central Arkansas. Miser has described the geology and manganese mineralization in some detail.2,3 The rocks of the area are sedimentary, consisting of sandstone, limestone, shale, and chert. The two formations of greatest importance,4 Fernvale lime- stone and Cason shale, are host rocks of the primary manganese mineralization.