EXTERNAL PUBLICATIONS

SUMMARY

The Explosives Regulations, 2014, set out the requirements for the safety of permanent stores of explosives at mines in Great Britain. Dutyholders must take appropriate measures to: prevent fire or explosions, limit their extent, and protect people. Measures include ensuring appropriate separation distances between the explosives storage and workers and people living in the area. HSE licenses the storage. Appropriate separation distances are well characterised for above ground storage and all licences to date (2022) are of this type. There is interest from the industry in using permanent stores of explosives underground at mines. However, to date appropriate separation distances have not been established. The main hazards from a potential explosion are the effects of the blast both within and outside the mine tunnel network. To determine appropriate separation distances, it is important to estimate the potential blast overpressure at sensitive locations. This report describes a mathematical model that estimates the propagation of a blast wave in rough-walled tunnel sections. The research to develop the model considered scientific understanding of blast propagation, and existing experimental data. The research identified that blast winds in tunnels may last far longer than those above ground. The model allows for varying diameters and surface roughness for the tunnel sections. HSE is using the model to inform decisions on appropriate separation distances for permanent explosives stores underground at mines. The model will be of interest to dutyholders applying for a licence.

This Research Report and the work it describes were funded by the Health and Safety Executive. Its contents, including any opinions and/or conclusions expressed, are those of the authors alone and do not necessarily reflect HSE policy.