Hensall Quarry, North Yorkshire


Project Brief
Enzygo was approached by FCC Environmental to produce a Hydrogeological Risk Assessment on an operating quarry to investigate the hydrogeological risks associated with extending their facility in Hensall, North Yorkshire. The site currently produces approximately 90,000 tonnes of sand per annum for sale in the local region.
By extending the quarry by 14.4 hectares (in 4 separate phases over a period of 10-12 years) it would allow for an estimated 1.065 million tonnes of sand to be removed.
The reason the client applied for an assessment was that the current excavation phase had less than 12 months of material remaining. Enzygo’s previous experience of working on integrated multidisciplinary projects made it the first choice to produce an Environmental Statement (ES) for the proposed new development. The hydrogeology section of the ES dealt with the risk of groundwater through activity associated with the quarry extension. Realistically, this involved a large-scale fuel spillage, as petroleum/fuel is the only groundwater contaminant which is stored or used on the site.

What We Did
Enzygo reviewed the local and regional geology and hydrogeology. We examined the probability and likelihood of contamination being present at the site or introduced through the proposed quarry extension works; and also looked at the potential severity and consequences of any impacts to the proposed site . The hydrogeology section of the ES identified receptors of any potential groundwater pollution, which included the Sherwood Sandstone aquifer which underlies the site, and the River Aire to the north.

What We Achieved
Enzygo provided its client FCC Environment with a detailed and comprehensive report on the regional and local hydrogeological regime at Hensall Quarry, and a considered assessment of how this may be affected by future quarry development. The modelled contaminant spill indicated that a high degree of contaminant adsorption and retardation would occur in the unsaturated zone, in the unlikely event of a large petrol/fuel spillage.