Geochemical and Mineralogical Characterisation of Historic Zn–Pb Mine Waste, Plombières, East Belgium

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.

Preface to the Thematic Section: Mine Tailings: Problem or Opportunity? Towards a Combined Remediation and Resource Recovery Approach

“…For the current study, an extractive waste depositional basin ("tailing pond") covering a surface area of 8000 m 2 was selected [3]. Bevandić et al previously constructed a 3D model describing the spatial variability of tailings [6]. Drillings were performed throughout the tailing pond, and variations in chemistry, mineralogy, and grain size were determined.…”

“…Six papers of the thematic section are dedicated to different aspects of the characterization, metal extraction, and valorization of the mineral fraction of the Neves Corvo extractive waste [6][7][8][9][10][11][12]. Neves Corvo is an underground Cu-Zn mine located in Southern Portugal.…”

Environmental and human health risk assessment of sulfidic mine waste: Bioaccessibility, leaching and mineralogy

“…There is approximately 11.4 Mt of mining waste present on site . Bricks from the former processing factory as well as pipes remaining from ore processing and fragments of slags have been found mixed with the tailings (Bevandić et al, 2021). Currently, there is a thin layer of vegetation and soil before reaching the different layers of tailings.…”

Incorporation of sulphidic mining waste material in ceramic roof tiles and blocks

“…In total, approximately 11.4 Mt of mining waste material is stored at the Plombières mining site (Helser & Cappuyns, 2021). The Plombières tailing material was sampled on-site through a hand excavated pit-hole and about 25 kg of material was taken from a yellow clayish layer (classified as yellow tailings) at 1.10 m depth (SUL_PL_62_I -Figure 2), being the most prominent layer in this tailing dam, with a thickness of ± 5 meters (Bevandid et al, 2021). Before sampling, the first meter of heterogeneous material (from appearance: soil, slag, black sand material, ceramic pipes, ceramic bricks, brown silt material and other remaining material) was removed.…”