Abstract
Niobium is an important element in making alloys for jet engines, beams and girders for building and oil rigs. Its superconducting properties are also used in particle accelerators, magnetic resonance imagery scanners. Ten surficial niobium mine tailings samples were collected in three tailings management areas.
Geochemistry and mineralogy show the metal bearing phases in the materials. This can be correlated with phases identified through sequential extractions and 24-hour solubility tests to quantify metal release. Bacterial presence is identified through DNA extraction and 16S sequencing to identify microbial contributors to weathering.
Predominant elements identified at % concentration levels within all sample sites included Al, Ba, Ca, Fe, Mg, Mn, Na, Nb, and P. Elements present at the mg/kg level included As, Cr, Co, Pb, U and V. Rare Earth Elements such as La, Ce and Nd were measured at the 10 to 800 mg/kg ranges. Since U is present, we also measured radium-226 which get precipitated using barium chloride. ICP-MS triple quad measurements of Radium-226 ranged from 120 to 320 mBq/g. Sulphur concentrations from 0.2 to 1.4% S and inorganic carbon from 5.6 to 9.7% alludes to neutral/saline mine drainage potential. Planned mineralogical investigations will identify mineral phases hosting elements of interest and sequential extractions will identify metals in different sorbing phases to assess their potential mobility. In addition, 24-hour freshwater solubility tests, alongside toxicity testing of leachates, will provide potential release information. Further studies to investigate influencing bacterial contributors are also ongoing.