Figure 9 – 28-foot mesh design with hybrid synchronization, electronic detonators, and non-electric detonators. Advance by shot The average advance obtained in the first 100 blasts executed was 7.58 m per shot, which represents an efficiency of 96.0% with respect to the drilling length of 28 feet. This value reflects an increase of 1.45 m per shot compared to blasts performed with 24-foot drilling, equivalent to a 23.7% increase in linear feed per shot. Figure 10 – Advance and efficiency per 28-foot blast shot. Overbreak To mitigate overbreak, operational controls were implemented during the drilling stage, aimed at maintaining the parallelism and geometric accuracy of the contour holes. However, given the extended length of 8 meters per drill, these actions were complemented with controlled blasting techniques, in order to preserve the stability of the excavated profile. In areas classified as type III rock, the tracking loading technique was used, while in type IV rock the use of control explosives was chosen. Both strategies were previously supported by 6.13 7.60 -10.0% 10.0% 30.0% 50.0% 70.0% 90.0% 110.0% 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 Efficiency Advance per blast (m) Advance and Efficiency per Shot Actual advance BM 24´ Average 28´ Efficiency
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