Increasing variability in precipitation patterns is expected to result from climate change in Canada. This effect has the potential to affect the performances of saturated covers in inhibiting acid rock drainage (ARD) and metal leaching (ML) processes. Because ARD and ML may cause the release of deleterious chemical species into the environment, such climate-change-driven impact was investigated using trickle leach columns. The physical, chemical, and mineralogical characteristics of the tailings as well as chemical composition of the leachate were measured before and after the column study. Results from the experiment showed that higher variability in precipitation regimes could enhance leaching of uranium. Leaching ranged from 67.1 to 90.1% of the total amount of U, with greater values associated with higher variability in precipitation patterns. Lower water levels and prolonged drought periods led to higher oxygen fluxes to the U tailings and dissolution of carbonate-bearing minerals. The release of carbonates could have enhanced uranium leaching through the formation of stable uranium-carbonate complexes in solution. Overall, this study shows that water level variation caused by varying precipitation patterns can significantly affect the drainage chemistry of saturated cover systems for which the level fluctuates freely near the tailings–cover interface.

CaCl₂-assisted Direct Reduction of Chromite (DRC) is a potentially lower energy alternative to conventional chromite smelting to produce ferrochrome (FeCr). This study investigates the technical feasibility of substituting petroleum coke (PC) with bio-carbon (BC) as the reductant in DRC and quantifies its effects on reduction behavior, alloy characteristics, and residual phase evolution. Chromite pellets containing CaCl₂ flux and either PC or BC were reduced under controlled conditions using thermogravimetric analysis and electric tube furnace experiments with continuous off-gas monitoring. Products were characterized using various methods including 3D X-ray microtomography, Scanning Electron Microscope (SEM)-based quantitative mineralogy, and Wavelength Dispersive Spectrometry using an Electron Probe Microanalyzer (WDS-EPMA). BC accelerated reduction kinetics relative to PC due to its devolatilization, which generated a microporous network and increased the reactive surface area. Correspondingly, peak CO flux occurred 8 min earlier with BC during vertical tube furnace tests. BC also produced finer FeCr alloys, with 15% of alloy volume below the initial reductant particle size compared with 3% for PC, reflecting enhanced alloy densification. Alloy compositions using both reductants met high-carbon FeCr specifications. BC use also promoted the formation of non-olivine and Cl-bearing slag phases, indicating that reductant type can influence the partitioning behavior of non-alloying elements within slag phases.