452 THE COLLIERY GUARDIAN. September 8, 1916. shells in great abundance. The output has grown from 54,589 tons in 1877 to 2,156,954 tons in 1913, of which latter quantity 959,510 tons, or 44-50 per cent., were exported. Coal, Coke, and By-Products from Coking. The coal has a brownish lustre, and is highly bitumi- nous. Owing to its great steaming power, high heating value, and uniform quality, it has acquired the reputa- tion of being the standard coal on the Asiatic markets. The average evaporating power of the lump coal is 9-72 lb., water evaporated at 212 degs. Fahr, by lib. The fine coal is peculiarly fitted for forging purposes, and commands a wide market both at home and in Chinese ports. The gas producing power of Miike coal has long been recognised by the gas works of Japan and China. It cakes easily, and coke of excellent quality is made in Koppers’ regenerative coke ovens, with a by-product plant installed at the colliery. The average production per ton of Miike coal is as follows :—Coke, 1,5001b.; gas, 11,000 cu. ft.; coal tar, 166 lb.; ammo- nium sulphate, 21-3 lb. There are at the Miike Colliery 92 Koppers’ regenera- tive coke ovens, with a by-product recovery plant pro- ducing over 100,000 tons of coke, and 1,420 tons of ammonium sulphate per annum, besides coal tar pro- ducts by distillation of the tar. Mine Workers, etc. The mine workers number 14,240 in all, including underground and surface hands. They are comfortably housed, and food is supplied at the canteens at cost prices, with a special reduction for long service miners. All the miners are required to save from 5 to 10 per cent, of their earnings, so as to provide against con- tingencies. Liberal rewards are given for regular attend- ance. The colliery provides three nurseries for the care of infants during the mothers’ absence at work. Education. The education of mine workers' children is receiving close attention. There are five elementary schools at the mines, with an aggregate attendance of over 1,000 children. Besides these, day and evening classes are opened for boys in the service of the colliery offices and works, giving them opportunities to pursue higher studies, and so qualify themselves for posts of responsi- bility. With the object of turning out competent fore- men and assistants in the fields of mining and engineer- ing, a special institution, with the name of the Mitsui Technical School, was established in 1907 near Omuta, under the patronage of the Mitsui families, for the benefit of the public. There are three departments, viz., mining, mechanical, and electrical engineering. One of the special characteristics of the school is that the whole of the colliery works are thrown open to the students, and there, in addition to the regular curri- culum, practical training is given them under the guidance of engineers and foremen. Hospital Accommodation. The Miike Colliery maintains a well-equipped hospital in Omuta intended exclusively for the colliery employees and their families. At present, the hospital has a staff of 19 physicians, 36 nurses, and a number of attendants. The hospital can accommodate 80 patients. It has a branch at each mine, and also at the Miike Harbour. Foreign Markets. The chief foreign markets for the Miike coal are Shanghai, Hong Kong, Singapore, Manila, and Java. Other large collieries are those of Tagawa, output 980,114 tons in 1913; Yamano, output 407,952 tons in 1913; Hondo, output 380,884 tons in 1913; Noborikawa, output 100,678 tons in 1913. In all these, as in the Miike mine, the welfare of the workers and their children is zealously seen to. Trade Openings Abroad.—The Sydney office of H.M. Trade Commissioner in Australia reports that a Sydney company, which has been formed for the purpose of carrying stocks and securing agencies for trading in engineering supplies, desires to get into touch with United Kingdom manufacturers of power plant and machinery of every description; and also of engineering supplies and accessories, with a view to obtain- ing agencies for Australia. The principal shareholders are understood to be associated with various local industries for which engineering supplies are required. United Kingdom manufacturers may obtain the name and address of the com- pany referred to on application to the Commercial Intelligence Branch of the Board of Trade, 73, Basinghall-street, London, E.C., where also catalogues may be consulted, together with the prospectus. The reference number (275) should be quoted. The Branch also has particulars of a Johannesburg engineer, who desires agencies for conveyor belts, balata belts, and mine trucks (reference number 276), and cables (reference number 277). The Serbian Mines.—The German-Bulgarian Union, of Dresden, has published the results of Bulgarian mineral researches carried out in the eastern part of Old Serbia. According to these researches, there are extensive coal basins between the Mava and the Peck, to the south-east of Pora- reva. The Dobra mine has a capacity of about 25,000 tons per year. On the Mirotch mountain, to the south of Tetkia, there is a coal bed 30 kiloms. (18-7 miles) in length. At Zaietchar, a colliery which has been working for the last 25 years, and is connected by rail with Radujevac, on the Danube, supplies from 30,000 to 40,000 tons per year. The Malakaon Reka bed is given a length of 3 kiloms. (1-8 miles), and an estimated capacity of 5,000,000 tons. Sonich, located at a distance of 22 kiloms. (13-7 miles) from the Belgrade- Sofia railway line, can yield a large coal output. The coal basin at Alexinats is given a length of 6 kiloms. (3-7 miles). Coal is also found at Rtani, near Kniajeva/ts, and in the Marava Valley, at Tzidilie. The copper mines are the Bor, the Kuka Dulkan, and the Maidan Pek mines; copper is also found at Studina, to the south of Nisch. The iron- bearing districts are in the Kapacnik range. PORTABLE COKE LOADER* fly L. R. W. Allison. The interlocking and adhesive characteristics of coke present a rather difficult problem in handling and load- ing. The great friction attending the action of coke on coke makes it practically impossible to dig into a pile of the material without an excessive crumbling and crush- ing of lumps and tearing apart of the formed mass, resulting in a large percentage of breeze. Portable elevators of bucket and chain design, while effecting a more uniform method of coke loading, have evident disadvantages for practical and economical operation. As the buckets move through a pile of coke for loading, the natural tendency is one of a compressive and crushing nature; also, the material must be shovelled in front and on top of the buckets as they move over the lower sprockets of the endless chain. This, together with the rapid action of the buckets, necessitates a constant re-handling and consequent increase in labour cost. The operation of a centrifugal bucket elevator, usually at high speed, demands con- siderable excess power through the energy expended in the natural crushing and tearing action, which often ranges as high as 10 to 15 horse-power beyond the actual requirements. A portable loader and screen of belt conveyor type has recently been devised to facilitate the handling and loading of coke at both large and small gas plants. This machine, which is shown in the accompanying illustrations, is known as the Lloyd portable coke loader; it obviates much of the difficulty attending the loading of cars or wagons, and is a noticeable improvement on the portable bucket elevator haulage system noted. The successful use of belt conveyors in gas plant operation, such as in moving coke from quenching Fig. 1.—View from Loading End s 4 * I ---W i L V Fig. 2.—Screen at Head. chutes under gas retorts to overhead storage bins, makes this type of machine the natural method, for loading coke from the yards. The loader offers a low power consumption and high capacity; of steel frame construc- tion, it affords great durability, and may be readily moved to any desired location. Construction Details. A conveyor belt of canvas or rubber, 20 in. wide, operates on a steel frame of latticed bar construction, as shown in the accompanying figure. Troughing idlers, arranged at an angle of 30 degs., are mounted on 5 in. channel iron cross pieces bolted to the trough plate. The belt is operated on 12 in. pulleys located on 23 ft. 10 in. centres, and is protected on the under side by the steel housing forming the trough plate, which has a width of about 2 ft. 9 in. The bottom, or tail, pulley is completely housed with sheet steel for protection against the coke screenings. The loader is operated at an incline of about 23 degs., and is equipped * Coal Age. with a 30 in. square feed hopper at the ground end. To provide for any slack or stretch in the belt an auto- matic take-up device is located on the under frame- work near the delivery end of the machine. This con- sists of a counterweighted pulley operating in steel guides. At the delivery end of the loader there is an overlip screen, known as the Cross patented screen, built in steps or sections, 12 in. long. The slots, running the full length of the section, are increased in width at the lower end to avoid clogging, thus' making it unneces- sary to stop the conveyor to clear the meshes. While either a shaking or stationary screen may be used, the former provides the best condition for the preparation of the coke as loaded; this is operated by means of two solid bronze eccentrics mounted on the countershaft, running at a speed of about 280 revolutions per minute. In employing the shaker screen, a 1 to 2 horse-power motor is required to drive the conveyor, this being geared directly to the countershaft, thus eliminating the neces- sity for high-speed chain drives. With the stationary screen, a reduction in the motor rating to about | or 1 horse-power is made. Cut gears are used for the motor drive. To provide for the breeze, or fine coke, delivered through the hoppered spout connected with the screen, a flat belt 14 in. wide is arranged to receive this and convey it to a cart, or there is a simple chute to the ground, or other receptacle as may be desired. This auxiliary conveyor belt is connected with the counter- shaft by a chain drive, and operates in the opposite direction to the main conveyor. By this arrangement the necessity for a storage hopper under the screen is eliminated, as well as the frequent interruption in operation due to stopping the machine to empty the container. The storage of breeze in a hopper is not satisfactory, particularly where conditions of moisture bring about a tendency to pack the sides. Method of Operation. The conveyor belt operates nor- mally at a speed of about 200 ft. per minute, with a capacity for screening and loading a 2-ton wagon in from three to four minutes with three men shovell- ing. Continuously operated, the machine has an aggregate capacity of about 35 tons per hour from the storage pile. Any choking is piac- tically impossible under normal conditions by reason of the elevating and' conveying capacity of the loader. In operation the coke falls with particular uniformity from the head pulley to the shaker screen, the largest lumps, those requiring but slight screening, dropping rapidly at the greatest distance from the feed belt on the screen, and thence into the wagon or other receiver. The majority of the breeze falls on the near side of the screen, almost immediately pass- ing through to the auxiliary con- veyor belt below. In this way the intermediate sizes of coke pass over the entire length of the shaker, and are thoroughly screened upon leaving the chute. In loading the machine by hand-shovelling the coke is handled but once, thus materially reducing the average percentage of breeze. The machine is mounted on a four-wheeled steel frame truck, which is provided with a wagon tongue for hauling by team to any desired location in the yard. The tongue may be swung back under the machine when in operation, making possible the loading of • a wagon or car at right angles to the conveyor, or with end backed under the screen chute. In this way uniform loading is accomplished without necessity for frequent trimming. Pumping Coal Through a Tube. — The Hammersmith Borough Council decided upon a scheme for transporting coal through a tube from the riverside wharf to the depot of the municipal electricity undertaking. The electrical engineer, in his annual report, shows that the scheme has been carried out, and is working successfully. Briefly, the scheme is to pump the coal, with water, through the tube. Last year the cost of carting coal from the railway was Is. 4Jd. a ton from Grove Station, and 2s. 2|d. from Shepherd’s Bush Station. Before the pumping scheme was in operation the cost of cart- ing from the wharf was 9|d. a ton. Now, the cost of pump- ing the coal is only 4-57d. per ton. The plant was started about the beginning of 1915, and at the commencement a certain amount of trouble was experienced until it was pro- perly tuned up, and the men trained in this new7 method of dealing with the coal. The scheme has justified itself. The Institute of Metals.—The annual autumn meeting of the Institute of Metals will be held on Wednesday, September 20, commencing at 4 p.m., in Burlington House, Piccadilly, London. A number of important metallurgical papers will be presented, including one on “ The Develop- ment of the Spelter Industry,” by E. A. Smith, A.R.S.M. The Government Research Council made a grant of 1'1.000 per annum towards the cost of carrying on the research inaugurated by the Institute of Metals Corrosion Committee into the causes of the corrosion of marine condenser tubes. Two salaried investigators have been appointed, in the persons of Capt. G. D. Bengough, D.Sc., and Dr. O. F. Hudson. They will conduct scientific researches on the committee’s condenser plant now about to be installed, by the courtesy of the Brighton Corporation, in the Brighton Elec- tricity Works.