Abstract
Mine tailings are filtered and stored on the surface in tailings impoundments to produce self-supporting tailings. However, tailings containing phyllosilicates, such as muscovite (fine tailings), can be susceptible to the effects of freeze-thaw and wet-dry cycles. These effects can impact their hydrogeochemical stability, including the modification of saturated hydraulic conductivity (ksat), water retention curve (CRE), and the mobility of chemical elements, particularly in the case of sulfide deposits. These effects also influence their physical stability, affecting mechanical strength and bearing capacity.
To mitigate these effects, the use of hydraulic binders to solidify and stabilize these tailings is becoming a necessity.
To this end, an experimental study was conducted on densified, solidified, and stabilized tailings from the Meliadine mine, using laboratory tests. The primary objective of the study was to assess the impact of a binder on the hydrogeochemical and mechanical behavior of muscovite-bearing mine tailings stored on the surface under northern conditions.
In these tests, small amounts of HE binder (0.5%, 1.5%, and 2%) were added to the filtered tailings, incorporating various proportions of muscovite (9.5%, 12.5%, and 15.5%) to create different mix recipes. These blends underwent several tests after 28 days of curing at a controlled temperature of 18°C.
The test results demonstrated that uniaxial compressive strength (UCS), hydraulic conductivity (ksat), water retention, and pH improved with the addition of 2% HE binder to muscovite-bearing mine tailings up to 15%. UCS increased from 61 kPa for unamended tailings to 493 kPa for tailings amended with 2% HE binder, while ksat improved from 10-7 m/s to 10-8 m/s, and pH increased from 7 to 9.
The results of this study highlight the beneficial effect of adding a binder amendment to phyllosilicate-bearing mine tailings stored on the surface under northern conditions. This will enable mining companies to implement a responsible, safe, and sustainable management system for the mining environment at a lower cost.