The sand and gravel resources of the country around Great Dunmow, Essex : description of 1:25,000 resource sheet TL 62

The geological maps of the Institute of Geological Sciences, pre-existing borehole information, and 98 boreholes drilled for the Industrial Minerals Assessment Unit form the basis of the assessment of the sand and gravel resources of the country around and north-east of Great Dunmow, Essex. All the deposits in the area that might be potentially workable for sand and gravel have been investigated and a simple statistical method has been used to estimate the volume. The reliability of the volume estimates is given at the symmetrical 95 per cent probability level. The 1:25 000 map is divided into 8 resource blocks, containing between 1.1 and 12.8 km2 of potentially workable sand and gravel. For each block the geology of the deposits is described, and the mineral-bearing area, the mean thicknesses of overburden and mineral and the mean gradings are stated. Detailed borehole data are also given. The geology, the position of the boreholes and the outlines of the resource blocks are shown on the accompanying map.