The geochemical composition of the clay can vary between layers and within the same layer in an individual deposit (Lurie, 1984). The variety among clay deposits is related to the different processes of formation (Deer, Howie, and Zussman, 1992). Bricks are manufactured from a wide variety of clay types, the behaviour of which during firing depends critically on the the clay mineralogy and chemical composition, but this relationship not well understood (Stein, 1982). Most clay in South Africa is used in the manufacturing of tiles, pipes, bricks, whiteware, refractories, and pottery. Keywords: geostatistics, facebrick clay, chemical composition, colour consistency. Geostatistical investigation of the chemical contents in other clay domains within the deposit is recommended, and could be extended to all facebrick manufacturers to assist in improving the colour consistency of their products. The geostatistical approach to understanding the distribution of elements in the clay allows miners to construct clay stockpiles of consistent quality for feeding the brick-making process. Consistency in the colour of facebricks depends critically on careful management of the variability in the K2O and Fe 2O 3 content of the clays. An analysis of the spatial continuity of these variables followed by ordinary kriging indicated that the upper white clay layer at Lenasia is richer in K 2O and Fe 2O 3 than the lower layer. Geostatistical investigations of the major element distributions (SiO 2, Al 2O 3, Fe 2O 3, and K 2O) and loss on ignition (Lol) were conducted. Homogeneity of the white clay raw materials mined at Lenasia is crucial for producing bricks of consistent colour. By blending varieties of naturally occurring white clay the manufacturers produce a unique range of facebrick products. Colour variation in bricks is influenced by the composition and consistency of the white clay raw material. IISchool of Mining Engineering, University of the Witwatersrand, South Africaīrick manufacturers supply a variety of uniquely coloured facebricks to the building industry, which requires a high level of colour consistency in the products. INational Ceramic Industries South Africa (Pty) Ltd, Aquarella Investment 389 (Pty) Ltd, Vereeniging Geostatistical techniques for improved management of brickmaking clays
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