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Mines in northern regions must heat underground workings, surface buildings, or process water due to frigid weather conditions. Mining companies commonly use fossil fuels for heating, which creates environmental challenges. An eco-conscious alternative, based on local resources and low electricity consumption, is the use of geothermal energy from the mine dewatering system. The Éléonore mine, an active underground mine located in a remote area in northern Québec (Canada), was selected as a case study. The geothermal resource was characterized to design a geothermal heat pump system (GHPS) adapted to mining operations. The energy balance was calculated to establish the heating energy requirements of the mine. Subsequently, the physicochemical properties of the water from different sampling points along the dewatering system were analyzed. Finally, a preliminary GHPS was designed to assess the amount of geothermal energy that can be extracted from the dewatering system of the mine. Under current conditions, a GHPS installed at the exit of the dewatering system could provide 39% of the 26.6 GWh/yr needed to heat the underground workings, reducing heating costs by 33% and greenhouse gas emissions by 1993 t/yr. A hydrogeological numerical model developed for the mine further suggests that a GHPS is sustainable throughout the life of the mine. Thus, this research indicates that, with adequate assessment, GHPSs have the potential to heat active mining operations and contribute to their energy needs in an environmental, affordable, and constant manner. [ABSTRACT FROM AUTHOR]

Exploitation of mineable oil sands in Canada has thus far produced over 50 km2 of tailings in ponds where the fine solids remain suspended for years, even decades. These ponds represent a major liability and environmental burden for operating companies, with their dewatering critical to their remediation. In this work, we used the chemistry of the tailing pond constituents to design an ionic liquid (IL) for dewatering the mature fine tailings (MFT), taking advantage of the ability to introduce unique and different functionalities into each ion of the IL. We chose a class of protic ILs whose ions will interact with the solids while rejecting water. As an example, octylammonium oleate can be used to remove more than 70% of the water from MFT. The nature of the ILs makes their use amenable to a variety of large‐scale separation techniques allowing engineering versatility in the design of the final process. [ABSTRACT FROM AUTHOR]

Accelerating dewatering of fluid fine tailings (FFT) to facilitate land reclamation is a major challenge to the oil sands industry in Canada. A new method was tested, addition of Tubifex to FFT. Tubifex is an indigenous earthworm in Canada. The survival rate tests showed that Tubifex can survive in oil sands tailings and penetrate to 42 cm depth (maximum depth tested). Columns (5 L of FFT) were set-up with tailings alone, Tubifex treated tailings and polymer- Tubifex treated tailings. Test results showed that ( a) the final mud-water interface of tailings alone was 26% higher than that of Tubifex treated tailings; ( b) solids content of Tubifex treated tailings was 21% more than that of tailings alone; ( c) Tubifex was capable to accelerate the dewatering process of both cationic and anionic polymer treated tailings; ( d) anionic polymer was superior in facilitating long-term dewatering and its coupled effects with Tubifex were better than the cationic polymer. [ABSTRACT FROM AUTHOR]