Chapter 41: Man-made hazards and obstructions

Man-made hazards in the ground take many forms. The principal forms discussed here are voids, contamination, unexploded weapons, obstructions and buried services. Many different geological materials have been mined in the UK over thousands of years. These include materials used for fuel (coal and oil shale), a wide variety of metal ores, non-metals and stone itself. Voids left by mining activity occur in a wide range of geological settings and both the mining methods and the nature of the voids themselves are similarly varied. References are made to methods of void detection and treatment. Man-made contamination in the ground is common in previously developed sites, especially those with an industrial history. A legacy of war brings the risk of encountering unexploded munitions in the ground. Processes for minimising the risks associated with contamination and unexploded weapons are discussed in this chapter. Man-made obstructions in the form of buried structures or parts of structures are commonly encountered in ground investigations and ground works. These can be particularly hazardous if they contain voids. Underground services are an almost ever-present hazard for ground investigations. Risk minimisation techniques are also discussed for these classes of hazard.