Environmental-Microbial Biotechnology Inside Mining Operations from an Engineering Viewpoint Based on LCA

Abstract

The relationship between the mining industry, society, and environment has been historically complex due to the number and scale of operational impacts. Today, the mining sector is at a tipping point to achieve equilibrium between high levels of production and minimizing environmental impacts. A feasible and novel approach to solve this need is the incorporation of concepts from industrial ecology to mining processes. Such approach could support an integrated management of materials available inside mine plants delivered by other industrial and depurative activities. Mining operations tend to be characterized as a conservative industry with few opportunities to innovate particularly with consideration to the application of microbial biotechnology at a large scale inside mineral processing plants, waste treatment, and ore recovery limited to bio-hydrometallurgical processing (e.g., Biolixiviation).

Several examples can be found inside mining operations where the application of microbial biotechnology has proven to improve the overall environmental impacts. One example is related to waste management in the mining industry; the main wastes are the solid deposits such as the tailings storage facilities, sterile piles, and lixiviation piles. Waste treatment has put focus on phytoremediation processes without the inclusion of environmental-microbial communities to complement phytoremediation treatment as recovering agents of ores.

Another environmental concern is the unseen pollution of small spills of oil that occur during the repair and maintenance of machinery, as well as accidents. Continuous fuel spills generally get absorbed by desert soils and sawdust as a low-cost and locally available sorbent material to control environmental pollution. This management strategy results in large amounts of fuel-contaminated materials. These materials have accumulated on hazardous waste landfills over time and require cleaning. In this case, bioremediation can potentially be a good approach to be applied as a sustainable remediation strategy. This method can be conducted through the direct action of microbial communities that use such organic compounds as an exogenous source of carbon and energy, converting them to more stable and innocuous forms benefitting the environment. This process has so far been proven at a lab scale under aerobic and anaerobic conditions, testing physical and chemical parameters, concentration, and quality of the contaminant. The difficulty of studies on oil spills is due to the high rates of uncertainty to determine kinetics of degradation and speeds of remediation as tools for the prediction of feasibility for treatment and the final residual concentration posttreatment.

To achieve a better understanding of the impact of the application of microbial biotechnologies for ore recovery, the use of life cycle assessment (LCA) will prove necessary. Our objective in this chapter is to make a conceptual model of environmental-microbial biotechnologies that can be applied to mining operations based on LCA methodology considering sustainable bioremediation processes and industrial ecology models as the main frameworks to innovate within industrial activities.