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Designs for extraction level layouts used in block caving mines may vary in terms of geometrical configuration and dimensions. The design of the extraction level in caving mines is mainly based on maximizing ore recovery at a low cost under safe and stable conditions. In this paper, we analysed the extraction level layouts commonly used as well as variations proposed with a specific focus on stability and productivity. The El Teniente layout was used as a base case with dimensions of 15 × 17.32 m2, production and extraction drifts of 4.3 × 3.6 m2, LHD of 7 yd3 and a productivity of 3,000 tpd per production drift. This base case was compared with three layouts: the Herringbone layout, a modified, enlarged El Teniente layout, and a modified, enlarged Square layout. Productivity was analysed through stochastic simulations using the software Arena; stability analysis used Examine3D software. Results indicated that in the new proposed layouts−the modified El Teniente layout and the modified Square layout−productivity increased by 33% and 39%, respectively, whereas the cycle time decreased by 23% and 25% with regards to the base case. In terms of stability, the Herringbone layout had the best safety conditions on the walls of the production and extraction drifts, whereas the modified, enlarged El Teniente layout had the best safety conditions on the roofs of the production drift. Finally, it is concluded that the modified layouts can contribute to increasing ore recovery while decreasing the cyle time without sacrificing stability. |
