Mineral Resources Bulletin Volume 5 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1850 Excerpt: ...quarrying would be practicable in this terrace is limited by the river level to little more than 20 feet. The boundaries of the pit as surveyed by R. A. Hobson in May, 1945, are shown in Figure 1. Probable reserves are 70,000 tons. Operator, --This deposit has been operated by Messrs. Bell Bros., of Guildford, for 30 years and has been the source of a large proportion of the natural bonded moulding sand used in most Perth and Fremantle foundries. Test Results.--Six samples (the location of which are marked on the plane table survey (Fig. 1)) were obtained from the pit in May, 1945. For discussion, the samples may be divided into three groups: --. (1) Sample No. 22. (2) Sample No. 24. (3) Samples Nos. 23, 25, 26 and 27. Sample No. 22 from a bank at the north-west end of the pit is supplied only to one large foundry. It is very " heavy " and contains 49 per cent. of clay substance, some of which is fine silt. In addition it is uneven and though 50 per cent. of the " sand " passes the finest sieve it contains coarser grains (in approximately equal amounts) from 70 to 270 mesh. As a result of the fine grain size, the uneven distribution and the high clay content, the permeability is very low. The strength, however, is high. Tests were conducted at moisture contents from eight to 11 per cent., but the material felt too dry for moulding until 10 per cent. of water had been added. The permeability would probably be improved by the addition of floor sand (nee later). Sample No. 24 from a heap on the floor of the quarry is also heavy but not as clayey. The grains are unevenly distributed; the bulk of them vary from 70 to 200 mesh, but fines increase the fineness number and decrease the permeability. The strength is high. If a heavy grade is require...