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Question 2: Box-cut design-45 marks. A mine in the Mooinooi area is expanding and needs to blast a box-cut to access the orebody. The proposed design will be 80 metres and the width is 50 metres. The deepest end of the box-cut is 16m. An Atlas Copco drill rig is available and capable of drilling 89mm holes. The rock type varies (from top to bottom) between soft weathered Pyroxenites to a more competent norite. Some 455m from the proposed blast site are overhead high voltage lines and 580m in the opposite direction is a water reservoir. 1. Design an in-fill drilling pattern, make recommendations regarding the explosives, comment on the charging and provide a timing pattern / plan. 2. Add a pre-split design to the 80m side of the box cut. 3. Clearly state your assumptions and add diagrams / sketches to motivate your answers