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stoping Sublevel stoping (SLS) is a method that can be implemented as sublevel open stoping (SLOS) or vertical crater retreat (VCR). The optimal conditions for the application of SLS are related to the geometry and inclination of the orebody and the stability of the walls and pillars that form the stopes (good geotechnical condition). The stability of the stope, pillar, and walls is determined by the geotechnical characteristics of the hangingwall and footwall (Potvin et al., 2001). SLS could be applied when the dip of the orebody is greater than 50°; this condition is based on the ability of the fragmented rock to flow due to gravity, when extracted at the production level (Pakalnis et al., 2011). The design of the sublevel stope includes the placement of the draw and the locations of the auxiliary and the drill levels. Figure 1 shows a schematic of the conceptual design of a large stope designed from level 1 to level 3. Note that the stope is defined as large when the height (H) and width (W) of the stope are greater than 30 m. In Figure 1, the dip of the footwall is 90° (vertical). The spacing of the sublevels (hi) depends on several factors, including the orebody geometry, the drilling technology, and capital costs. Figure 1 also includes a reference to a variation of ore grade with the stope height. The in situ grades are represented by horizontal layers G1, G2, and G3, where (G1>G2>G3). In current planning practices, ore grades are planned to be extracted in the order from G1 to G3 without considering the mixing that might occur during gravity flow. Figure 2 show a typical draw or production level layout for a large sublevel stope, where DD are drifts where a long drawbell is located, while PD is the production drift where, in general, mechanized equipment such as LHDs operates. In the case presented in Figure 2, drawbells are spaced at Dd metres while drawpoints are spaced at Dpe metres. Generally, for SLS, Dpe is approximately 15–18 m while Dd is 48 m (Contador et al., 2001). Figure 3 shows the application of SLS with the footwall inclined at an angle a and the hangingwall inclined at b degrees to the horizontal. In this case, the location of the drawpoints must be considered with respect to the maximum recovery of ore, especially if unplanned dilution can enter the stope due to instability. This is related to the gravity flow properties of fragmented rock. The role of gravity flow in the design and planning of large sublevel stopes