ERA-MIN Tools for sustainable gold mining in EU (SUSMIN)
| Reference number | |
| Coordinator | Luleå tekniska universitet |
| Funding from Vinnova | SEK 1 540 400 |
| Project duration | January 2014 - December 2016 |
| Status | Completed |
Purpose and goal
The object of this study was to evaluate the stability of As in tailings from a cyanide-leaching process, and in cemented paste (solidification by the addition of alkaline residues). The tailings were net acid-generating and contained elevated concentrations of Arsenic(1000 ppm). Results from the study shows that the As-leaching from the cemented paste were affected by curing time, chemical condition and degree of water saturation.
Expected results and effects
Results shows that a majority of As in the unmodified tailings was associated to iron-phases, which were stable at a pH > 4. Solidification resulted in an obstructed sulphide oxidation, a minor increase of As-leaching, but also in the formation of a significant amount of acid-intolerant As-species. This underlines the necessity of maintaining high saturation levels in the cemented paste to prevent acidic conditions. The project resulted in two peer-reviewed scientific articles and a licentiate thesis.
Planned approach and implementation
The project has been conducted in cooperation with a mining company. The mining comapny has provided knowledge about cemented paste, the cyanide-leaching-process and tailings. Valid methods have been used to characterize tailings and the cemented paste and theirs leachates. Evaluation of As phases formed in cemented paste was a challenge due to fralatively low concentrations of As.