Re-Mining of Waste Rock Dumps from a Closed Lead–Zinc Mine—Characterisation of the Residuals

Abstract

The lead–zinc mine Bleiberg-Kreuth located in the Austrian federal state of Carinthia has had a long mining history, spanning from the early 14th century to the 1990s. The mining and processing activities undertaken over the centuries and, consequently, the composition of the waste rock material changed throughout this period. Today, the focus on waste rock dumps is motivated firstly by environmental interests and secondly by economic aspects. This article provides a comprehensive approach for the characterisation of three different waste rock dumps. The characterisation covers both mineralogical–geological methods and those involving the use of a mineral processor. The characterisation method presented herein starts with the sampling and calculation of the sampling mass, followed by sieve analysis and sink–float analysis, resulting in a two-dimensional fractional analysis. The consolidated results of the fractional and chemical analyses allow for a simplified forecast model for an ideal classification and density separation. Finally, the practical processability of a pre-concentration was tested by trials for comminution, classification, and density sorting.