Interview with Hannah Fraser, hydrogeologist
Is Whitemoss suitable for a hazardous waste site?
There are a number of aspects of the site in this specific setting that mean that the controls on groundwater below the site are quite complex. The geology under the site is a layer of peat, then some sands and gravels, and then quite a thick layer of clay, and then below that are the Coal Measures. The particular area where they want to extend the landfill has been mined and there are two shafts on the site, so there are direct connections down to the coal measures, which are very heavily fractured and faulted, because of the mining and natural fracturing.
The shafts go from the surface, down though the layers of peat, sands and gravels and down into the Coal Measures, and they go some distance into the coal measures.
What does that mean may happen to the site?
The Coal Measures are an aquifer and carry water. They tend to carry water in fractures and fissures and within the rock itself where there are sandstone layers within the Coal Measures. The landfill is going to be excavated down through the peat, sand and mud into the Coal Measures, and at that point, if all you did was dig a big hole into the Coal Measures, the groundwater, which is under pressure, would come up above the level of the coal measures, and the level would settle somewhere quite close to ground level. So it’s going to require active pumping to keep the groundwater below the base of the landfill.