What is a design criterion for the storage of explosives underground?

The design criterion for the storage of explosives underground focuses on safety and compliance with regulation standards. In the context of mining operations, particularly in Queensland, explosives must indeed be stored in a designated area known as a Non-Explosive Risk Zone (NERZ). This is a crucial criterion because the purpose of the NERZ is to minimize risks associated with the accidental detonation of explosives and ensure the safety of personnel and equipment involved in mining operations.

Storing explosives in a NERZ ensures that there is a clear separation from areas where personnel frequently work, thereby maintaining safety and management practices that comply with legislative requirements. The NERZ is also responsible for managing the influence of explosive materials in proximity to other hazardous substances or operational zones.

The other options do not sufficiently represent the critical safety and operational regulations necessary for the underground storage of explosives, highlighting why the choice concerning the NERZ is the appropriate answer.