Benzaazoua, Professor Mostafa1
1Research institute of mining and environment (RIME) – University of Quebec UQAT, Canada
Worldwide, the mining industry during the previous century played a so important role in the first industrial revolution, but at the same time mine operators increasingly suffered from a very bad image related to important environmental liabilities and difficult societal acceptance. In fact, mine exploitations that still follow the linear economy scheme extract finite ore resources and generate high volume of solid wastes (“Take-make-dispose”), where the only profits are those of the valuable minerals. For this reason, legislations and policies nowadays keep evolving to become increasingly binding regarding mine wastes management practices and rules and towards waste preservation from weathering and pollution release.
Mine waste management strategies remain complex to achieve effectively and very cost consuming. This is why the environmental management is becoming increasingly integrated in the mine life cycle, instead of being a late expenses after mine closure. More and more countries around the world privilege other actions that tend to reduce the amount of wastes to be deposited within mine site surfaces. Among actions already used, the mine industry proceed with i) upstream geometallurgical modelling, ii) smart and rational extraction of ores in underground or open pit mines, iii) maximisation of in situ reuse of mine wastes with or without reprocessing for novel practices like underground backfilling, and iv) waste reuse in the reclamation process (covers construction, once the mine wastes are proven clean, or after waste reprocessing for decontamination).
Presently, the main challenge of the mine of future consist of developing more symbiotic strategies that include more circular economy (“make-use-recycle”), to be able to valorize and recycle mine wastes outside of mining sites in other industrial sectors like geo-materials and infrastructures construction for civil engineering. This strategy depends on many factors that could conditioned by at least four conditions: 1) Adequate legislative arsenal, including incentives, 2) Geometallurgical integrated waste management strategy, including on-site ore/waste sorting, reprocessing and in situ reuse, 3) An efficient environmental prediction tool for mine wastes all along mine cycles and once within their recycled state, and finally 4) The possibility as well as the acceptance of reusing mine waste out of mining site. As finality, this philosophy may allow transforming wastes into secondary raw materials for other industrial sectors, such in civil engineering.
Mine wastes metal revalorization or reuse in situ and out of mine sites as sands and/or aggregates for roads, concretes, bricks manufactures … represent promising ways that might help in reducing the environmental impacts of mining activities. Some examples from works undertaken at RIME-UQAT or in Morocco around the phosphate mining industry will be presented in this presentation. A focus on the legislation and its importance, as the one in force in Quebec province (Canada), will be detailed as an example that encourage mining circular economy. Then, examples will be presented to illustrate the main challenges that have to take-up in this field.
Research institute of mining and environment (RIME) – University of Quebec UQAT, Canada