Mineralogical investigations on the tailings of “Schneckenstein” Germany

The mineral content of the tailings material was determined using X-ray mineral phase analysis as well as polarisation and cathodoluminescence microscopy. In addition, mineral separation using heavy liquids was also conducted. Silicate minerals dominate the mineralogy of the tailings, with Muscovite and Quartz exceeding 25% and 30% respectively in most of the samples analysed. Two types of clay mineral were identified: chlorite and kaolinite with concentrations ranging from 2 to 12% and from 2 to 16% respectively. In addition, albite, microcline, orthoclase, potash feldspar and hornblende together with trace amounts of andalusite were identified in the mineral matrix. Dolomite is the most widespread carbonate mineral while only trace amounts of calcite and ankerite were recorded. Only trace amounts of sulphide minerals such as pyrite and chalcopyrite were recorded. On the basis of mineral separation by heavy liquids, low concentrations of ankerite, barite, biotite, goetite, hematite, and siderite were identified. Basing on the chemical conditions of the uranium leaching, it may be expected that an important amounts of trace metals including Ba and As are an association with the mentioned clays. Certain elements such as Cu, Pb, Zn, Ni, Co, Cd, Mg and Sr contents are more linked to oxides and hydroxides.