Sarcouncil Journal of Engineering and Computer Sciences

Abstract: While mining plays a pivotal role in global economic development, it often results in severely degraded landscapes that present long-term ecological and socio-economic challenges. Conventional mine land rehabilitation approaches which are often dependent on Portland cement and other carbon-intensive materials, increasingly present various challenges such as environmental footprint, cost, and limited long-term effectiveness. In response, sustainable technologies such as bio-cementation and geopolymers have emerged as promising alternatives that align with low-carbon development goals and circular economy principles. This review critically examines the potential of bio-cementation and geopolymers in sustainable mine land rehabilitation, highlighting their principles, applications, and limitations. Bio-cementation, primarily based on microbially induced calcium carbonate precipitation (MICP), enhances soil stability, reduces permeability, suppresses dust, and immobilizes toxic metals through carbonate precipitation. Various case studies demonstrate its effectiveness in stabilizing mine tailings and controlling erosion, although challenges still remain in their scalability, nutrient costs, and durability under variable environmental conditions. Geopolymers, synthesized through the alkali activation of aluminosilicate precursors such as fly ash, slag, and mine tailings, offer superior mechanical strength, chemical durability, and the ability to encapsulate heavy metals. Their environmental benefits, including up to 80% lower CO₂ emissions compared to cement, are balanced against constraints such as precursor variability, activator cost, and limited long-term field data. A comparative analysis of the two approaches reveals complementary strengths: bio-cementation excels in eco-compatibility and in-situ stabilization, while geopolymers provide robust structural integrity and long-term contaminant immobilization. Key barriers include performance variability, logistical constraints in remote mining areas, and limited industry awareness. The integration of bio-cementation and geopolymer strategies may provide multifunctional rehabilitation systems that address both geotechnical and environmental needs.