COAL WASTAGE

Otago Witness, Issue 3442, 2 March 1920, Page 7

COAL WASTAGE

UTILISATION OF PRODUCTS. NEW ZEALAND LAGGING BEHIND. During the course of a, most instructive address to the annual conference of the New Zealand Society of Civil Engineers on the 25th the president (Mr W. Ferguson) discussed the question ot waste in our natural and artificial products. He said that one of the results to be obtained from systematic investigation and experiments in industrial matters probably would be in the direction of eliminating waste of all kinds, not only by the -utilisation of produots, both natural and artificial, now wasted or insufficiently utilised, but also by the saving of labour both by its more efficient use and by the introduction of labour aiding plant and improved machinery. One of the most notable examples of waste in New Zealand was that in connection with our coal. Unfortunately our coals, whether anthracitic, bituminous, or brown, were remarkably broken and soft in their nature. Not only were there found in many of the mines large areas of the seams of coal that were too shattered and soft to be worked under present conditions, but even in the hardest and best of the _ seams worked there was an immense quantity of small coal and dust produced both during extraction and through the subsequent screening adopted to produce large coal suitable to the present conditions of domestic, industrial, and transport purposes. The fin© and soft coal was of nearly as high a calorific power as the largo and hard coal, but owing to our inability to utilise it in th© form of dust, huge quantities were©wasted —a waste which owing to our limited coal supplies in the dominion was little short of criminal. He believed that a very limited amount of experimentation might lead to the early utilisation of large quantities of coal now wasted, with a consequent immediate reduction in the price of all classes of coal. It must be remembered that at present the finished article as it was delivered in the form of screened coal had to bear not only the whole cost of the labour of screeningj but also that of the waste coals not marketed as well as a portion of the cost of that portion of the smalls for which a market could under present conditions be found. There seemed to be. no reason why our railway authorities, our steam-generated electric power stations, our freezing works, or some one of more of them, should not in their, own interests and indirectly in "the interests of the dominion put down plant for the purpose by experimentation of solving this problem. It was not as if the matter of the use of powdered fuel <-was quite a novelty in New Zealand, for it was largely used in the manufacture of cement. Incidentally the use of powdered fuel in our industries would lead to the adoption of coal cutting machinery in our mines, as the size of the coal produced would be of small moment, and this would probably lead to a solution of a difficulty that was at present a serious one in New Zealand in connection with coal miners, their wages, and conditions of labour. A Fuel Research Board—a board having as its director Sir George Beilby —was set up in 1917 by the British Department of Scientific and Industrial Research, and as part of its functions it, in 1918, sent a representative to the United States of America —Mr L. C. Harvey —to report on the question of powdered fuel. The board published last year as its first special report a very able booklet by Mr Harvey, showing what he found in a three months' visit to the States. The fact that over 10,000,000 tons of coal per annum were now burnt in a pulverised condition as dust in America showed not only that the matter had there passed the experimental stage, but also that we in New Zealand had been lagging •behind and had not made the most of our opportunities in connection with the use of one of our wasted products. It was represented that pulverised fuel was_ easily handled, having semi-fluid properties, it flowed readily and could be distributed to the various furnaces in an industrial works either by mechanical means or forced in a mass through pipes by compressed air or suspended as dust in a current of air. After inspecting the application of the coal-dust systems to steam-raising in stationary boilers of the ordinary and marine types and in locomotives, as well as its use in various metallurgical industries, and in cement and other works, and after an investigation of nine out of the 10 systems upon the American market, Mr Harvey reported that the advantages of burning pulverised coal had been definitely proved in practice, and included the utilisation of the heat values of almost any grade of fuel, whether anthracite, bituminous, lignite, or peat, to a greater degree than by any other means. Ho claimed an economy, by burning coal as dust in an air blast, of from 20 to 50 per cent., and that coal ha.ving high percentages of ash, which was now wasted as culm or slack at th© mines, could be utilised. Experience showed that under suitable conditions ther© was no danger from explosion of the coal dust or of spontaneous combustion, and that the slag or dust deposited from the ash in the" fuel could be conveniently handled and removed from the boiler ashpits and from nearly all types of industrial furnaces. One of the most important advantages that he claimed for the use of the r.ii-blast powdered-fuel furnace was the great saving of labour as compared with hand-stoking, or even with machine-stoking, and particularly in the fir r lag of railway locomotive boilers, whilst not in the least advantage to b© gained was the abatement of the smoke nuisance which results from the more perfect combustion obtained. Even assuming that all the advantages claimed by its. advocates for the crushing of coal to a fine powder and its injection into the combustion chamber by an air blast so proportioned as to obtain a perfect combustion of the particles while in suspension, were not completely substantiated, there would apparently remain sufficient advantages in the utilisation of a valuable product now wasted to warrant both careful investigation and immediate action by the engineers' of New Zealandi.