Based on earlier published work on barium sulphate-alumina-silica systems, Amdel submitted a proposal to the South Australian Department of Mines to examine the application of these reported methods to South Australian barytes and kaolin. The proposal was accepted in July 1969. Previous work on the barium sulphate-alumina-silica system, by Russell et al., by Grylicki, and by Singer led to the suggestion that refractory materials could be produced by heating a mixture of barytes and kaolin at about 1000°C to form the barium feldspar, celsian (BaAl2Si208). An investigation of this system by Segnit and Gelb showed that a 1:1 molar mixture of barytes and kaolin, fired to 1000°C in a reducing atmosphere, produced the celsian phase. Such mixtures reacted rapidly and formed a loosely packed body with very low mechanical strength, probably due to incomplete reaction.