Improving the quality of sampling on the basis of drilling with freezing (applied to phosphorite deposits of Estonia and Leningrad region)

Abstract

Prospective reserves of coquina phosphorite deposits in Estonia and the Leningrad Region are estimated at 2-3 billion t. Genetically, they are associated with the thickness of quartz-obol sandy sediments of the Pakerort horizon of the Early Ordovician, spread over almost the entire territory of Estonia and stretching 320 km to the east of it (Leningrad Region). The thickness of the productive strata varies from 1-6 m, with an average thickness of 4 m. Phosphorite-bearing sandy sediments with erosion lie on sandstones, siltstones or clays of Cambrian.