Combining ultramafic mine tailings and acidic mine drainage via mineral carbonation to sequester carbon dioxide, presents an opportunity to minimise waste on mine sites. Low pH mine water with trace element concentrations can be effectively treated by high magnesium mine tailings, a useful source of finely ground reactive matrix. By using milled tailings for mineral carbonation, there are negligible energy requirements for communition of ore rocks to reduce particle size. This study aimed to assess the technical applicability of reacting ultramafic tailings and acidic mine water through mineral carbonation technology in the mining industry. Dissolution has been identified as the rate limiting stage in mineral carbonation; hence the study focused on identifying optimal dissolution conditions. Ultramafic tailings (particle size <100 m) derived from serpentinite ore, were reacted with a typical mine water that was synthesised in the laboratory. through variances in the solid to liquid ratios and temperature of dissolution, a maximum five per cent magnesium dissolution efficiency was reached at 50 g l and 100c. the acidic mine water was neutralised (from ph><2 to ph ~6) and iron, copper and zinc ion concentrations reduced significantly during the formation of solid precipitates. carbonation was undertaken by injecting carbon dioxide into the magnesium-rich solution to form stable carbonates. the experimental work demonstrated proof of concept; however, dissolution efficiency and carbon dioxide sequestration was low, indicating that further research would be required before larger scale implementation.citation:malli, h, bouzalakos, s and timms, w, 2015. ultramafic mine tailings to treat acidic mine water and lock away carbon through mineral carbonation, in proceedings tailings and mine waste management for the 21st century , pp 133-136 (the australasian institute of mining and metallurgy: melbourne).>