A DEPOSIT OF ALUM,

Otago Witness, Issue 2525, 6 August 1902, Page 13

A DEPOSIT OF ALUM,

In our issue of Monday last we published a letter from a correspondent asking for particular regarding- the use and value of what he describes as a deposit of alum. The matter was brought under -the noti. % 3 of Mr D. B. Waters, lecturer in the Otago School of Mine 3, who has kindly supplied the following notes of general interest: —

The occurrence mentioned by the coi respondent will most likely be aluminite or alum stone, from which a large amount of the alum of commerce is manufactured. When pure aluminite consists of hydrous sulphate of alumina and potash it generally, however, contains more or less of foreign substances, which lessen its value according to their nature and amount. In Now South Wales there exists a large deposit of aluminite of various grades. This is mined, and the best quality exported to England. The following figures from the "Mineral Resources of New South Wales" show the annual shipments and their value during some iccent years, statistics not being a\ailable later than 1899: —

The value per ton thus varies, but durmg the la-sfc three years mentioned, it 9Cems to Inn c remained fairly constant at £3 per ton. The la«t shipments, during the year 1899, are stated to have been forwarded to the United A-lkali Company's works at Runcorn, near Liverpool, England. The most satisfactory test of its value, if it exists in quantity, is to =end a small representative sample to tho firm mentioned, who would no doubt give particulars in regard to its commercial worth. No notice in given anywhere of its use, if it be aktmimte, in its natural state.

Year. 1890 1891 1892 1593 1801 1895 1806 1897 1898 1899 ** T tonnage. 220 704 821 1284 862 832 1372 724 2941 921 * »i \ alue. £3000 1888 3284 5136 3446 3328 4116 2172 8823 2763