Acid Mine Drainage (AMD) and Acid Rock Drainage (ARD)
Acid mine drainage (AMD) and acid rock drainage (ARD) present a significant environmental challenge due to the oxidation of metal sulfides in waste rock or mine tailings. The removal of sulfide from mine waste (e.g., tailings) can be achieved using thermal treatment technologies with highly elevated temperatures (e.g., in the range of 600 to 1000°C for removal of sulfide from pyrite). Savron’s ex-situ smoldering (STARx) systems are a low cost, energy efficient process, which have demonstrated potential for remediating AMD/ARD-generating wastes. Temperatures sufficient for complete sulfide removal (i.e., in excess of 1000°C) can be generated via smoldering with the use of a surrogate fuel.
Savron is currently conducting proof-of-concept laboratory studies to explore the application of smoldering combustion to treat mine tailings and other mining waste materials. Results to date demonstrate that:
- Successful smoldering treatment of tailings with a vegetable oil amendment can achieve temperatures in the range of 600°C and 77% reduction in total sulfur.
- Granular activated carbon (GAC) can be used to support smoldering combustion to achieve higher temperatures (i.e., >1000°C) when added to tailings at ~40 to 60 g/kg.
On-going laboratory development work continues and opportunities for a field demonstration of the technology are being evaluated.