Mineral resources in Lower Brule Indian Reservation

On the Lower Brule Indian Reservation in South Dakota, about 3 million tons of metallic manganese are in low-grade deposits in the DeGrey Member of the Pierre Shale on the reservation. The geology and methods of mining and processing this sub-economic mineral resource have been studied extensively; technologically, extraction of manganese is possible. However, an efficient, economical method to separate manganese-bearing nodules from the shale host rocks has yet to be found. The manganiferous nodules occur in the Oacoma zone of the Sully shale member (De-Grey Member) which is a subdivision of the South Dakota Pierre Shale formation. These nodular deposits have an interesting similarity in stratigraphical position, lithology and manganese content to those of the Porcupine Mountain area in Manitoba.

位于美国南达科他州的下布鲁尔印第安保留地内，其辖区内的皮埃尔页岩（Pierre Shale）德格雷段（DeGrey Member）中赋存有约300万吨低品位金属锰矿床。针对该次经济矿产资源的地质特征、采矿及选矿工艺，学界已开展广泛研究；从技术层面而言，锰的提取具备可行性。然而，目前仍未研发出可从页岩围岩中高效分离含锰结核的经济可行方法。含锰结核赋存于隶属于南达科他州皮埃尔页岩组的萨利页岩段（Sully shale member，即德格雷段）的奥科马带（Oacoma zone）中。此类结核状矿床在地层位置、岩性及锰含量方面，与加拿大曼尼托巴省波丘派恩山地区的同类矿床具有显著相似性。