Integrated Mine Tailings Management: Possibilities for Coal Tailings Deposits in Santa Catarina State, Brazil

摘要

Brazilian run-of-mine coals (ROM) contain high levels of impurities (rock minerals and pyrite), requiring concentration procedures. The coal tailing deposits demand large physical area, change the topography and generate the acid mine drainage (AMD). It is estimated that more than 300 millions tonnes of coal tailings exists in the south of Brazil, generating environmental impacts and economic costs. This work characterizes a typical coal tailing deposit, seeking the separation of three fractions for future reuse: (a) a fraction of low density; (b) a fraction of intermediate density; and (c) a fraction of high density. The characterization studies included particle size analysis, dense medium studies, XRD, acid acid-base accounting tests, and determination of ash and total sulphur. The results showed that 67% of the material is composed by coarse particles, 14% by fine particles and 19% by the slurry from the settling ponds. It is possible, by gravimetric concentration, to recover 34.2% of the material for energy generation and 9.2% of the material as a pyrite rich concentrate. The remaining material, with intermediate density, has a lower acid generation potential and can be ground and prepared to find applications in civil engineering (as aggregate) and agriculture (as rocks for crops). This approach brings a new outlook to tailings management in the Brazilian coalbased industries. The study showed that it is possible to decrease or even eliminate the environmental liabilities of coal tailing deposits by means of Research, Development and Innovation (R&D&I). The coal companies can diversify their production, and, even after decommission of the mining exploration, continues their activities processing the coal wastes.