When can you go inby your last support in a mine?

The choice to set up temporary support as a condition for going inby your last support in a mine is correct because it emphasizes the importance of safety and proper procedures in mining operations. In underground mining, support systems are critical to ensuring the stability of mine workings. Going inby the last support is inherently risky, as the further a miner moves from secured areas, the greater the potential for ground failure or collapse.

Setting up temporary support allows miners to create a safer work environment before proceeding deeper into the mine. This process involves using materials such as timber or steel to ensure that the area remains stable while work is being conducted. Without adequate support, miners could expose themselves to severe hazards, including rock falls.

The other options present situations that typically do not justify moving past the last support. Routine checks generally involve evaluating the condition of supported areas rather than venturing into unsupported regions. Authorizations from a supervisor indicate a level of formality in safety protocols, yet authorization alone is not sufficient; it must also involve assurance that proper support is in place. Lastly, safety drills are important for training but do not provide the necessary physical support to ensure safety when moving beyond the last established support in the mine.