The sand and gravel resources of the country around Terling, Essex : description of 1:25,000 resource sheet TL 71

Geological maps prepared by the Institute of Geological Sciences, data from 121 boreholes drilled during a feasibility study in 1966-67 and for the Mineral Assessment Unit in 1968- 69, and other pre-existing borehole information form the basis for the assessment of sand and gravel resources in the Terling area, Essex (1:25 000 sheet TL 71). The sheet is divided into resource blocks, each ideally containing 10 km2 of mineral (potentially workable sand and gravel). A simple statistical method has been applied to estimate the mineral volume in each block where at least five sample points are available. The reliability of the volume estimates is given at the 95 per cent confidence level. For each block the inferred area of mineral, the estimated average thickness of overburden and of mineral and the calculated mean grading of mineral samples are also given. The geology of the various deposits occurring in the sheet and details of each resource block are described. Borehole positions, the geology and topography, and mineral resource information are shown on the accompanying 1:25 000 map TL 71. Detailed borehole data are given.