| dc.description.abstract | Backfilling technology is utilized globally to improve ore recovery, reduce mine-generated waste,
and provide stability to underground voids. Cemented paste backfill (CPB), a mixture of mine
tailings, cement binder, and mixing water is the desired method of backfilling. After filling the
underground space (called a stope), CPB is required to provide ground resistance to the surrounding
rock walls, be used as a roof for continued mining operations, or a floor for underground mine
workers and equipment. A challenge to the use of CPB is the vast quantities of sulfide minerals
such as pyrite and pyrrhotite containing irons present in the waste mine tailings. The sulfate anions
generated from the oxidation of sulfide minerals not only interfere with the progression of cement
hydration but also produce expansive hydration products, including gypsum and ettringite. As a
result, the sulfate anions are able to change the microstructure and macroscale geomechanical
behavior and material properties of the CPB materials. Therefore, it is of theoretical and practical
importance to fully consider sulfate-induced evolution of mechanical behavior and properties of
CPB materials. Moreover, the ability to extract ore up to the CPB pillar provides benefits to the
profitability of the mine. However, mine stopes may reach enormous depthsin excess of 100m into
the earth. Therefore, the CPB is not only subject to the internal chemical effects of the sulfide
minerals but also to the complex loading conditions present within the mine stope. As a type of
brittle material, the failure processes in the CPB matrix are governed by crack propagation under
field loading conditions. Such an event will not only reduce mine profitability but can also
potentially be life-threatening to the underground workers. As a method to mitigate such risk, fiber
reinforcement (FR-CPB) is a promising approach. Hence, it is crucial to systematically investigate
the effect of sulfate solution on the tensile and fracture behavior and properties of fiber-reinforced
CPB materials. [...] | en_US |
