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Otago Daily Times, Issue 27078, 12 May 1949, Page 10

Mr J. Rogers, research lecturer in mineral dressing, told the Daily Times yesterday that the equipment which had come from Britain, Canada and the United States was modelled on full-scale machinery used in industry. " Our work will be fairly closely integrated,” Mr Rogers said, “ with that of the recentlyappointed professor of coal mining, Mr J. Ivon Graham, in the field of coal cleaning or coal preparation. Already we have been asked by the State Coal Department to undertake research in coal washing.” Besides coal experimental work, Mr Rogers is collaborating with the Pottery and Ceramic Research Association, which has its laboratory in Wellington, in efforts to produce highgrade materials for industry from New Zealand resources of felspar and clay. From the Cobb River valley in Nelson, where there are large deposits of talc magnesite rock, have come samples to be separated into their constituent parts by the flotation method, which enables a pure talcum powder to be recovered. Magnesite is, however, the more valuable product. A heavy demand exists for it in Australia, where the Broken Hill 'Proprietary has consumed nearly all known resources in that country and now uses it at the rate of 1200 tons a month. Magnesite also has possibilities as a fertiliser for magnesiumdeficient soils. Another project for reference to the mineral dressing laboratories concerns the cement industry. A prominent firm wants to know the exact size of the grains of dust and this will be discovered by the use of one of the many ingenious machines which have been installed. Established in the basement of the Mining School, the laboratories were designed by members of the teaching staff. Apparatus to break up ores treating them to remove unwanted minerals have been placed in what is known as the crushing room. A special system, also designed by a member of the staff, to clear the room of dust and thus remove any danger of silicosis, has been fixed in position. In the concentration laboratory the minerals required are separated from those that are unwanted on the basis of their different properties, such as their specific gravity, magnetism, and surface properties. Ingenious Contrivances Interesting among the apparatus in the concentration room is that used to separate minerals by flotation. A mixture of minerals, .already ground finely, is placed in the machine, various chemicals which alter the surface of one of the minerals and not of the others are added and air bubbles are introduced. These adhere to the surface of the treated mineral particles which are buoyed to the top where they collect as froth and are removed by the simple expedient of lifting them off. y

A difficulty hindering the full use of the laboratories is lack of technical staff.

Mr Rogers himself has been awarded a Nuffield Traveiling Scholarship and will go to Canada and the United States at the e.nd of September to study the latest trends in mineral dressing.