Exploitation
Victor Patson Mutambo; Barnabas Mpaka; Pardon Sinkala; Matheus Ipinge
Abstract
This study evaluates rock mass ratings, rock strength parameters, and the geological structures of the dominant rock units alongside a quantitative assessment of the performance of various anchor systems for enhanced ground support in mine excavations located within the Synclinorium area. This region ...
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This study evaluates rock mass ratings, rock strength parameters, and the geological structures of the dominant rock units alongside a quantitative assessment of the performance of various anchor systems for enhanced ground support in mine excavations located within the Synclinorium area. This region is notable for its complex, folded, and mineralized formations. The deeper levels of the synclinorium are characterised by poor ground conditions, faults, and shear zones. Stress induced by mining activities worsens the situation. These factors have significantly impacted the stability of excavation. Fall-of-ground (FOG) incidents have exhibited a concerning increase over the past nine years. This trend necessitates a thorough investigation into the factors contributing to it. Our research employed empirical methods for rock mass classification, specifically utilising Barton’s Q system and Bieniawski and Scanline mapping of geological structures along the crosscut walls at a 1.50 m elevation. We conducted borehole logging and pull-out tests to evaluate the working and ultimate capacities of rock bolt anchors deployed in the excavations. Borehole cores were analysed for geological formations, colour, and grain size. The findings indicate that excavations in areas with mined-through rock and stone necessitate urgent and intensive roof support to stabilise the surrounding rock mass, thereby enhancing standing time. Additionally, we identified joint patterns, joint orientations, and the various stresses affecting the surrounding rock mass in the crosscuts. The above highlights the importance of geological data in the design of effective ground control and support mechanisms. Pull-out testing conducted at the 3360 level recorded a 28.6% failure rate in primary development despite very competent ground.
J. Manyepa; V. Patson Mutambo
Abstract
Designing suitable extraction methods for mining randomly occurring pocket formation of gemstones has never been easy at the Musakashi emerald mine due to the limited geological information. In order to improve the productivity as well as the recovery, in this work, we undertake a detailed ...
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Designing suitable extraction methods for mining randomly occurring pocket formation of gemstones has never been easy at the Musakashi emerald mine due to the limited geological information. In order to improve the productivity as well as the recovery, in this work, we undertake a detailed geological survey (airborne, surface mapping, geochemical sampling, and trenching activities), and review, analyze, and establish the appropriate extraction methods, and conduct the economic viability of the mining emeralds in the Musakashi area. A total of 51 holes are drilled in order to define the mineralization and estimate the mineral resource for the rubble ore and the in-situ ore zones using the Surpac Geovia software. The diamond drilling unravels the existence of an alteration zone enveloping the shales in an area of 150m by 100m. The emerald is localized within these reaction zones, and is estimated to extend to a depth of about 20–30m below the surface. The total mineral resource stands at 345, 290 grams for the rubble ore and 123,870 grams for the discordant veins. From the geological information obtained, a trial pit design is established with a target of increasing recovery of emeralds from the current 10 kg to 100 kg per year.
