The author, Dr M B Mgangira, is to be commended for tackling the subject of the usage of industrial waste which, as far as the writer is aware, is an almost ignored topic in South Africa. There are, however, apparently some anomalies in the paper and it would be useful if these could be clarified so that a better understanding of the results could be gained. The first is that the properties of the foundry waste are not complete; a particle size distribution curve or a table of the data is necessary so that the implication of what seems to be relatively high Atterberg Limits can be understood. In addition the author states that the foundry sand contains 10 bentonite whereas table 2 shows the clay fraction is only 4 : are these values compatible or is the apparent discrepancy due to the very high temperature to which the foundry sand must have been subjected?
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