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Cemented paste backfill (CPB)/rock interface shear resistance results in a spatiotemporal stress reduction in CPB and thus affects the mechanical stability of CPB structure in underground excavations. To study the stress distribution in CPB structure, an integrated model consisting of a cohesive zone model for CPB/rock interface behavior and a multiphysics model for hydrating CPB behavior is developed. The predictability of the proposed model is validated against measurements from laboratory tests and field studies. Thereafter, the validated model is used to investigate the influence of curing time, stope geometry, and field backfilling operation on the spatiotemporal stress development in CPB structure. It has been found that the CPB/rock interface loading is able to reduce the stress levels in CPB by up to 75%, and taking advantage of this phenomenon can significantly reduce the operation cost. Moreover, there exists a critical stope width that governs the extent of stress reduction in CPB. In addition, continuous mining activity in the secondary stope exerts limited impact on the stress redistribution in the primary backfill body. These findings provide practical guidance for the safe design of a CPB structure as well as a more strategic mining plan for the adjacent ore body. [ABSTRACT FROM AUTHOR]

Accurate and frequent measurement of mine water quality is essential for timely management and regulatory requirements. At mines, traditional water sample collection practices are sometimes unsafe or impractical due to accessibility challenges. Unmanned aerial vehicle (UAV)-based remote water sampling has benefits in accessing small, shallow and isolated waterbodies in hazardous environments. In this study, an integrated electromechanical pneumatic system was developed to provide an effective, efficient and safer means to acquire mine water samples using UAVs. The system was tested to collect and analyse ponded water from a tailings storage facility to measure pH, electrical conductivity and dissolved oxygen. [ABSTRACT FROM AUTHOR]

Roughness on rock joints produces a variable aperture across the joints and increases the flow path length. These conditions should be taken into account for a good approximation from cubic law. In this paper, the concept of local true aperture and tortuosity is applied to assumed joints where surfaces are matched to each other and correspond with standard Joint Roughness Coefficient (JRC) profiles. Furthermore, the hydraulic behaviour of JRC profiles is studied by a new laboratory experiment setup. The analytical approach provides new insights into the effects of roughness on hydraulic properties of rock joints. The results indicate that for a constant mechanical aperture, both the minimum local aperture and hydraulic aperture decrease with increasing JRC. Furthermore, tortuosity and standard deviation of local true aperture increase with JRC increment. The trend obtained between different parameters and JRC shows an obvious fluctuation for JRC lower than 10. On one hand, the results of this study along with a critical review of previous studies demonstrate that JRC profiles cannot present a precise roughness increment when JRC is less than 10. A new laboratory setup was designed to study the flow behaviour of JRC profiles. The results obtained from laboratory experiments under linear flow conditions validate the accuracy of the applied analytical method. [ABSTRACT FROM PUBLISHER]

At mine sites in a stressed watershed, groundwater dominated licensed water take, and water-use productivity was dependent on site practices and constraints. Solutions for mining and water in this context include: (1) state-based water governance within a national framework; (2) information tools, including mine site water-reporting frameworks; (3) site water sharing and salt trading; and (4) technologies and leading practices. While water reporting has improved, evaluating the significance of hydrological changes over the long-term remains a challenge, particularly for groundwater and saline discharges to rivers. [ABSTRACT FROM AUTHOR]