The sand and gravel resources of the country north of Harlow, Essex : description of 1:25,000 resource sheet TL 41

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 sand and gravel in the area north of Harlow, Essex. All deposits in the area which 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 95 per cent probability level. The l :25 000 map is divided into five resource blocks containing between 8.3 and 14.2 km2 of sand and gravel. For each block the geology of the deposits is described and the mineral-bearing area, the mean thickness 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.