Abstract
Mine wastes and tailings derived from historical processing may contain significant contents of valuable metals due to processing being less efficient in the past. The Plombières tailings pond in eastern Belgium was selected as a case study to determine mineralogical and geochemical characteristics of the different mine waste materials found at the site. Four types of material were classified: soil, metallurgical waste, brown tailings and yellow tailings. The distribution of the mine wastes was investigated with drill holes, pit-holes and geophysical methods. Samples of the materials were assessed with grain size analysis, and mineralogical and geochemical techniques. The mine wastes dominantly consist of SiO2, Al2O3 and Fe2O3. The cover material, comprising soil and metallurgical waste is highly heterogeneous in terms of mineralogy, geochemistry and grain size. The metallurgical waste has a high concentration of metals (Zn: 0.1 to 24 wt.% and Pb: 0.1 to 10.1 wt.%). In the tailings materials, Pb and Zn vary from 10 ppm to 8.5 wt.% and from 51 ppm to 4 wt.%, respectively. The mining wastes comprises mainly quartz, amorphous phases and phyllosilicates, with minor contents of Fe-oxide and Pb- and Zn-bearing minerals. Based on the mineralogical and geochemical properties, the different potential applications of the four waste material types were determined. Additionally, the theoretical economic potential of Pb and Zn in the mine wastes was estimated.
Highlights
The demand for raw and critical raw materials (CRM) is growing day by day
This study aimed to identify the different mine waste materials present at the Plombières tailings pond (Belgium) by using a combination of geophysics and drilling
Sampling started with 6 exploratory drill holes that were used to constrain a grid of 15 additional drill holes (Figure 2) based on where tailings material was found, while avoiding vegetation and slopes, where there are large amounts of whole pipes and metallurgical waste
Summary
The demand for raw and critical raw materials (CRM) is growing day by day. This results in an increasing dependence of the world on a few countries, such as China, SouthAfrica, USA and Russia, which are rich in CRM resources. The demand for raw and critical raw materials (CRM) is growing day by day. This results in an increasing dependence of the world on a few countries, such as China, South. In the search for alternative sources of base metals and CRMs, some of the most promising resources are mine wastes, tailings. Historic tailings may contain significant concentrations of valuable metals, such as important base (e.g., Pb, Zn, Cu) and critical (e.g., In, Ge, Ga) metals, of which the latter were not previously economically feasible to recover. But the often-high heavy metal content of tailings combined with the propensity for sulphidic-rich tailings materials to produce acid mine drainage (AMD) means that tailings could pose a significant risk to the environment [6,7]. Mine wastes represent a potential risk for humans, as the contained metals and metalloids (e.g., Pb, Cr, Cd, As) can enter the human body via inhalation, digestion or even direct contact, to contribute towards a range of illnesses [8,9]
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