1006 THE COLLIERY GUARDIAN. November 24, 1916. the various points required, and it is provided with all the latest devices for the best possible operation. The capacity is 450 tons per hour. The slack coal is to be drawn out from the bin to lorries, and used in coke ovens, and the refuse is to be drawn out from the bottom of the refuse bin and disposed of. The motive power provided is as follows :—One 125 horse-power motor for the gravity discharge machine and revolving screens; one 60 horse-power motor for shaking screens, cross slack conveyor, and conveyor to the gravity discharge machine; one 50 horse-power motor for picking tables and pea and re-screening conveyors; one 30 horse-power motor for refuse and mixing conveyor. It will be readily seen from the description of these plants that each tipple proposition presents its own ■ ■ Fig. 3.—Picking Tablesiand Loading Booms of the Allegheny River Mining Company. to Egg Picking Table and Loading Boom Nut Picking Table and Loading Boom Refuse Boxes Mixing Chutes from Loading Booms Chute from Slack Rescreen Conveyor R. R. Cars Gravity Discharge Elevator Chute to Revolving Screen Revolving Screen Slack Hopper Under Revolving Screen Pea Chute to Wood Bin No. 4 Track— Nut Nut, Pea and Slack Nut and Slack No. 5 Track— Slack from Bin 1 Retarding Conveyor 12 Chutes from Slack Mixing Conveyor 22 2 Bar Screen 13 Pea and Rescreen Conveyor 23 3 Slack Hopper 14 Pea Loading Chutes 24 4 Discharge Chute 15 Slack Rescreen Chute 25 5 Emergency R. O. M. Valve 16 Pea Chute to Bin 26 6 Upper Shaking Screen 17 Domestic Pea Bin 7 Lower Shaking Screen 18 Swivel Pea Chute 27 8 Slack Gathering Hopper 19 Screen Hopper and Chute to Screen 28 9 Reversible Cross Slack Conveyor Conveyor 29 10 Slack Conveyor to V Bucket Elevator 20 Refuse and Rescreen Conveyor 30 11 Refuse and Slack Mixing Conveyor 21 Lump Picking Table and Loading Boom 31 No. 1 Track— Pea No. 2 Track— Lump Lump, Pea and. Slack Lump and Slack No. 3 Track— Egg Egg and Lump Ejrg and Nut Egg, Lump and Nut Egg, Lump, Pea & Slack Fig. 4.—General Arrangement of the Powhatan Coal and Coke Co.’s Loading Arrangement. peculiar problems and requirements, and that the design- ing of the equipment is a special branch of conveying machinery engineering, requiring a great deal of experi- ence and familiarity with all sorts of devices for accom- plishing the desired results. The engineer must also have the proper sort of initiative for making the design, in order to get the devices and general arrangement best suited to the particular case, so that the equipment will meet the requirements and show the greatest return on the amount of money invested.—Coal Age. The estate of the late Mr. J. Dempster, principal of Dempster Limited, gas plant manufacturers, Newton Heath, has been sworn at £432,448. FUEL DIFFICULTIES. Mr. A. E. McKenzie, in the course of his presidential address to the members of the Manchester local section of the Instiitutdion of Electrical Engineers on the 14th inst., referred to the organisation of engineering indus- tries, and stated that one association had recently been formed representing firms having an aggregate capital of over 150 millions sterling. Dealing with the linking up of power stations, he remarked that several munici- palities had already proved the great financial saving that could be effected by inter-connecting, especially in the lowering of fuel costs and the reduction in the quantity of stand-by plant necessary under such schemes. Without being unduly optimistic, he thought No. 3 Track—cont. Egg, Lump and Slack Egg, Nut, Pea and Slack Egg, Pea and Slack Egg and Slack Picked R. O. M. No. 5 Track—cont. Pea from Bin Pea and SI ck Direct Emergency R. O. M. Nos. 6-7 Tracks — For Coke Lorries Screening and they might anticipate the more economical production of electricity in the near future, and the removal of many of those restrictions which had hampered the industry in the past. That would result in the more extended use of electricity for all purposes, and conse- quently largely increased benefits to the nation, for undoubtedly one of the greatest factors in securing a successful future for the manufacturers of the country was a cheap supply of electricity. The Summer Time Act, in his opinion, had been an unqualified success. So far as it had been possible to institute comparisons at the generating stations in Manchester, it was estimated that the reduction in lighting output from the chief station for the period covered by the Act was equivalent to 1 per cent, of the total output, while the consequent saving in coal was about 600 tons. At other Manchester Corporation stations the reduction was approximately 1^ per cent, of the output, with a saving in coal of about 400 tons. Turning to the question of fuel, he observed that great difficulty had been experienced by both gaf and electricity supply undertakings during the past yeai in obtaining their necessary supplies of fuel, even where it could be proved, as in Manchester, that practically the whole output was for war work. Very meagre assistance had been obtained from the Government. The Act for limiting prices at the pit had been of little real value to many, and they heard in many quarters of colliery companies evading its provisions. There was no doubt that additional legislation was required to enable electricity stations, which were vital to the carry- ing on of the war, and to the nation’s interest in peace times, to obtain coal in sufficient quantities for their needs, and at reasonable prices. The fuel procurable to-day was inferior to that obtained before the war from the same pits, because of the greater percentage of the dirt content. Indeed, a large proportion of the total fuel now offered was, until recent years, unsaleable. During the late coal strike more than one large elec- tricity undertaking was only enabled to keep running by burning fuel which had been thrown on the rubbish tip in the preceding years. To burn inferior coal called for conditions different from those previously obtaining in most stations, but higher draught and modern grates suggested that frequently the lower grades of fuel could be used economically. The present high prices of fuel had caused colliery managers to recognise more fully the very great waste that undoubtedly had taken place at many pits. As much as from 10 to 15 per cent, of the total output from some mines had in the past been left in the mines, as being too small to warrant raising to the surface. Government control should in future obviate that wastage of our great national asset. The high prices now obtaining for all classes of fuel undoubtedly called for the more efficient management of boiler houses, where it was generally admitted more could be done to improve the economical working of a supply undertaking than in any other department. The man in charge of the working of a large boiler house should be an engineer of exceptional ability, and he Scaia Carliaui ieasier Wetyh Scale Car Dump /Kick Fig. 5.—Tipple Arrangement, Powhatan Coal and Coke Company. Back Car Trip Making should be well paid, because the salary of such a man was a very small fraction of the saving he would effect. To him should fall the duties of seeing that combustion was obtained as perfectly as circumstances would allow, and that correct gas, water, and steam temperatures were maintained. The indispensability of the analytical chemists in electricity undertakings of any magnitude was not yet sufficiently recognised. Only by regular testing could one ensure getting fuel of anything approaching constant quality from most collieries, and the knowledge that such tests were made was usually sufficient to make contractors careful in sending supplies to works where that practice was followed. Nor should the chemist’s efforts be confined to raw fuel tests. He should be responsible for the correct treatment of the feed water, and for seeing that scale and corrosion in the boilers were prevented, and the like. The lar«e power station of the future, he believed, would have°a proportion of boilers gas fired, the proportion being based upon the load factor in such manner that the extra capital incurred by the installation of by-product recovery plants would be remunerative, and the by-products of the bulk of the fuel used recovered. Gas firing was not could not be—a means of direct saving of fuel- The two-stage process of conversion of coal to »as„a . ffas to steam must necessarily involve heat inefficiencies exceeding those in the direct conversion of coal to steam. Skilled analysis and extensive experi- ence tended to show, however, that with improved pro- ducers the aggregate value of by-products recoverable from coal by conversion to gas equalled or exceeded the original coal value, and when extra capital and labour charges were taken into account, the procedure led to a substantial rebate on fuel costs. There were isolated cases on record in the days when slack could be bought at 6s. or 7s. a ton, where large boiler installations were fired throughout the year substantially for nothing, and as the value of the various by-products" fluctuated largely in sympathy with coal values, one might expect a net saving by the system of between 4s. and 7s. per ton of coal consumed. As to the exact method which would survive, one hesitated to express an opinion. There were, broadly speaking, two fundamental types of gas recovery plants : (a) Low temperature distillation, in which coal was converted to coke or smokeless fuel yielding gas, spirits such as benzols, toluol, and the like, heavier oils, tar, and a comparatively small amount of sulphate of ammonia; (6) producer, "in which coal was burned to ash with yield of abundant gas, a compara- tively poor tar, the residual value of which about paid