Exploration and appraisal of plastic sedimentary clays for the fine ceramics industry

The term ‘sedimentary plastic clays for the fine ceramic industry’ is discussed. The deposits of these kaolinite-rich plastic clays are classified into four types: (1) complex tectonic basins, (2) interactive multi-basin deposits, (3) large lens deposits and (4) recent lenses. The aims of exploration and appraisal are defined as (a) geological evaluation, (b) production planning, (c) clay component classification, (d) identification of marketing and blend parameters and (e) provision of information for investment decisions. These aims are common to all deposits and demand the rigorous testing of undisturbed sample, which generally achieved by core drilling. The variety of core drilling techniques used in the deposit is described. The application of these drilling techniques and the patterns of boreholes used, is related to the diversity of geological occurrence and characteristics of the four types of deposit in a series of case studies. It is concluded that, in spite of the aims of exploration and appraisal being coincident, the diversity of the occurrence has led to favoured core drilling techniques and borehole patterns in the various deposit types, in order to achieve those aims in the most cost effective manner.