C.— 2.

A coal-briquetting maclxine capable of producing 50 tons of ovoids per eighthour day has been added to the aforementioned carbonizing plant at Sockburn. Bituminous and sub-bituminous slack coals from the West Coast nunes are blended for the purpose of manufacturing the ovoids which are transported from the briquetting press by belt conveyer to storage-bins. From there they are bagged or delivered loose to motor-trucks and railway wagons. During the year ended 31st December, 1933, the coal carbonizing and briquetting plant at Rotowaro, operated by Waikato Carbonization, Ltd., carried on continuously until October, when it was closed down for a period during the summer months, chiefly on account of the discontinuance by the Railway Board of the use of carbonettes. „ , Nevertheless there was an increased demand for carbonettes from other consumers in all parts of the North Island, while the encouraging sales of by-products, such as fuel oil and weed-killer, led the directors still further to prosecute research in the company's laboratory in regard to the production of Diesel oils, disinfectant, £inci sheep-dip. The following figures show the totals of production during the year Raw coal treated . . . • • ■ • ■ 21,936 tons. Carbonettes manufactured . . . . ■ • 12,425 tons. Oil made 135 > 320 g allons - Pitch made .. • • • • • • tons. For the production of motor-spirit a large hydrogenation plant is being built in England. As motor-spirit has to be vaporized before being used m internalcombustion engines some eminent British engineers consider that hydrogenation is a needless process, as coal-gas, produced at gasworks, can be compressed into cylinders for use in motor-vehicles. Rupa-Diesel engines, capable of operating with various types of powdered fuel, such as powdered coal, lignite, or wood-waste, are being manufactured in Germany. 1 , . The use, in stationary steam-plants, of slack coal from our sub-bituminous seams is extending, but it is urgent that other uses should be found to avoid the present large waste of such slack. LABORATORY INVESTIGATIONS. The work carried out for the Department by the Dominion Analyst has consisted chiefly of the testing of prospectors' samples from all parts of the Dominion, analyses of coal from the State Coal-mines, and examination of mme-air trom numerous collieries for noxious and inflammable gases, on behalf of the Chief inspector of Coal-mines and his staff. Work having as its object the rendering of concrete impervious to sulphide and sulphated mine-waters underground has been continued, with a fair amount of success. Ready means for the detection and estimation of sulphuretted hydrogen in mine atmospheres have been further investigated. Regular and systematic work on the special properties of New Zealand coals has not been possible since the disbandment of the Coal Research Association two years ago. it is gratifying, however, to note, as a result of the briquetting investigation carried out by the association, that a commercial plant has been erected near Christcnurc for the briquetting of slack coal. PERSONS EMPLOYED IN OR ABOUT MINES AND STONE-QUARRIES. The following table shows the number of persons employed in each inspection district during 1933 and 1932 : —-

4

Inspection District. Totals. Classification. TTT ri Southern 1 Increase Northern West Coast (of' (regt of South 1933 ] 932 . ; 0 r (North Island). South Island), j jsland). i Decrease. Gold, silver, and tungsten ore 1,195 2,332 2,685 6,212 3,636 Inc.2,576 ' 6 _ i 373 2,064 949 4,386 4,636 Deo. 250 Stone-quarries under the Stone- 1,304 139 268 1,711 1,888 „ 177 quarries Act le „ Oil 9 • • • ■ 9 16 „ 7 Totals .. •• 3,881 4,535 3,902 12,318 10,176 Inc.2,142