Following the international oil crisis in the 1970s, Hong Kong's two electricity generating companies built large coal-fired stations which now produce about 1Mt of pulverised fuel ash (PFA) p.a. In common with most other countries the disposal of this ash presents problems, exacerbated in Hong Kong by its small land and sea areas and strict environmental controls. The opportunity to help overcome this problem - and, at the same time, improve the quality - of structural concrete by using classified ash as a partial cement replacement - was recognised in the early 1980s. In 1982 the first local classification plant, at the Hong Kong Electric Co. Ltd's station at Lamma Island, was commissioned. Some of the ash from China Light & Power Co. Ltd's
plant at Tap Shek Kok is now classified, and some is used as a raw material for the production of OPC to BS12 in the nearby China Cement Co. (HK) Ltd works and in the production of 15% and 25% PPFAC blends.