March 30, 1917. THE COLLIERY GUARDIAN. 625 ness of the cuts obtained is very remarkable. Much of the secret of success lies in the correct design of the dephlegmator. The record of one plant shows the following average figures for the distillation of crude benzol containing toluene:—Pure benzene, 85-3 per cent.; intermediates, 3-4; pure toluene, 9'8; residue, 1’3; loss, 0-2 per cent. The residue is often allowed to go to waste; but may be mixed with the coke oven tar without injury. The water and caustic soda used in the agitator are drained to the sewer. The acid sludge drained from the agitator is delivered to a boiler T, in which it is treated with direct steam. This effects a separation of the resinous materials in the form of a heavy carbona- ceous spongy deposit. An acid of about 40 degs. Be is recovered, and may be used on the coke plant for making ammonium sulphate. The boiler is covered during the operation of steaming and the escaping vapours are condensed in a cooler. Regarding other details, such as the arrangement of pumps, storage tanks, and piping, the diagram is self- explanatory. The upkeep of a benzol plant costs remarkably little, and the labour required in operation is small. A com- plete plant handling 5,000 gals, of light oil per 24 hours is operated by five men on day turn and three men on night turn, with two chemists for control test- ing, and three labourers on day turn only for loading shipments and for general utility purposes. The apparatus that is subjected to the most severe conditions is the superheaters. Spare superheaters should always be provided, and the apparatus arranged so as to be readily interchanged. All apparatus for heating and cooling the wash oil should be so arranged that each individual unit can be taken out easily with- out disturbing the other apparatus. All apparatus, with the exception of that exposed to sulphuric acid, is made of iron and steel, no special alloys being required. It is very essential that the utmost precaution be taken in the arrangement of the piping to obviate the possi- bility of accidental mixing of the different products. AN AMERICAN CONCRETE TIPPLE.* By W. G. Burroughs. The wooden tipple of the Black Diamond Coal Com- pany, near Lathrop, Athens County, Ohio, having been destroyed by fire, the new tipple, shown in the accom- panying illustrations, was constructed, in which no chances of a similar disaster were taken. At the tipple everything is of concrete, including the columns, floors, sides, roof, trestle, bins, power house, reservoir, etc. The tipple is of monolith construction. The concrete for all the parts was run, -as far as possible, at the same time, making the entire construction one unit. A 1 : 2 : 4 concrete mixture was used, and it took about one week to run the entire tipple. This mono- lith construction is claimed to be superior to a steel tipple, because the vibration is distributed over the entire structure, whereas in a steel tipple all the strain is put on the rivets, which may become loosened. The tipple proper is approximately 100 ft. long by 30ft. wide, and 30ft. from the ground to the main floor. The highest point of the top is 62 ft. from the ground. The columns are 19 in. by 18 in. The sides are of concrete and plastered tile. The concrete is built up 6 ft. above the main floor, so as to stop any cars that may jump the track after being dumped. Above the concrete the walls are plastered tile. A concrete trestle, approximately 250ft. long by 19 ft. wide, 25 ft. high on the average, leads from the mine brack to the tipple. The columns of the trestle are 12 in. by 12 in., and rest on reinforced concrete footings; the soil in which they are sunk is clay of medium consis- tency. A shorter concrete trestle leads from the main trestle to a waste pile. On the main trestle there is a switch connecting with the empty track which operates automatically. The STEAM RAISING WITH PULVERISED COAL. In a discussion at a recent meeting of the American Society of Mechanical Engineers, Mr. G. H. Barnhurst gave details of a plant for preparing and burning pulverised low-grade coals, including lignite, under boilers at the shops of the Missouri, Kansas, and Texas Railway Com] any. The eight O’Brien 250-horse power boilers are arranged independently with a space of 4 ft. 8 in. between the settings of each pair of two boilers, and a space of 28 ft. 4 in. between the two batteries for feed pumps, auxiliaries, etc. The boilers are to carry 150 lb. steam pressure, the feed water being delivered at 208 degs. Fahr., with a boiler efficiency of 70 per cent., and working at full capa- city for 10 hours, and half capacity for 14 hours, about 158,000 lb. of coal will be consumed in 24 hours. When the contemplated additional boilers are added, a total of 94 tons per day of 24 hours will be required. Two 42 in. Fuller mills running 12 hours per day will readily produce 96 tons to 100 tons of pulverised coal, or more than ample for the plant. The Pulverising Plant. The coal is dumped directly from the cars into a concrete and steel hopper beneath the track which runs parallel and adjacent to the power-house and coal plant. As a large percentage of it will be mine run, a 20 in. by 24 in. spike-toothed roll crusher is mounted directly beneath the hopper to break down the large lumps. This crusher is driven by a belt-connected motor in the inclined tunnel leading from the track hopper to the coal plant. A 20 in. belt conveyor, with its receiving end directly All fife Railroad Tracks ■j I ■ ~: 1 I T,pp'U^ l tv B^erHowe Fig. 1.—Concrete Tipple of the Black Diamond Coal Company : r I st ~7 tn rif "S’ £ Fig. 2.—Typical Cross Sections. Since benzol is a by-product of coke and gas making, those items in the cost of its production which are involved also in coke and gas production are not chargeable to the benzol. In other words, the cost of making coke oven benzol includes only the cost of its extraction from the coke oven gas, and that of its purification. This cost in the United States will vary according to local conditions, but usually lies between 4c. and 7c. per gal. The effect of the removal of benzol on the calorific value of the gas has been worked out by J. W. Shaeffer, who recently published his results showing that the actual loss in the calorific value of the gas amounts to about 5-8 per cent., which is a figure repre- senting the average practice of about 30 by-product coke oven plants. The figure agrees well with theoretical considerations. The result is that more debenzolised gas has to be used for accomplishing a given, heating effect'. Assuming that one ton of coal makes 11,000 cu. ft. of gas, a reduction of 5’8 per cent, is equivalent to 638 cu. ft. less gas. As boiler fuel, this gas is worth about 6c. per 1,000 cu. ft., so that the reduction may be figured to cost about 3'83c. per ton of coal, i.e., about 8 per cent, of the normal value (based on gasolene prices) of the total benzol recovered. Coal Production in Spain. — Recently issued statistics relating to the output of coal in Spain indicate that native supplies are being drawn upon to a much greater extent than before, in consequence of the difficulty of obtaining imported fuel. The output of coal, anthracite, and lignite in 1916 totalled 5,406,899 tons, an increase of 720,152 tons on 1915, and of 244,092 tons on 1914. Some of the details relating to last year’s output are estimates, but may be regarded as approximately correct. Electric Power.—The President of the Board of Trade has appointed a Committee to consider and report what, steps should be taken, whether by legislation or otherwise, to ensure that there shall be an adequate and economical supply of electric power for all classes of consumers in the United Kingdom, particularly industries which depend upon a cheap supply cr power for their development. The chairman is Mr. F. Huth-Jackson, and the secretary Mr. M. J. Collins, to whom all communications on the work of the Committee should be addressed at the Board of Trade, 7, Whitehall- gardens, S.W.l. electric locomotive coming from th© mine makes a “ flying switch ” into this empty track, th© loads con- tinuing down th© main track to the tipple. The loco- motive starts back for th© mine with th© empty trip, and by its own weight throws the switch, so that the side track connects with the main track. At th© tipple platform the loaded min© cars ar© dumped on a Phillips cross-over dump, and then pass over a series of screens, the lump coal going into bins or rail- road cars, as desired. The finer coal passes into an elevator hopper, from which it is lifted 50 ft. by a bucket conveyor to a revolving screen, which sizes the coal; it then goes through chutes into bins, from which it is loaded into railroad cars below. The concrete power house is adjacent to the tipple, as shown in th© accompanying illustrations. Coal used as fuel for the boilers goes from the top of the bucket elevator in the tipple through an outsid© chute into bins in the power house directly over and in front of the boilers. Enough coal is contained in these bins to operate the boilers 48 hours. From these fuel bins chutes lead downward to a short distance above the floor of th© boiler room, and 5 ft. horizontally in front of the boilers, where a pile of five or six bushels.of coal is kept on the floor ready for use. Th© power plant consists of three 150 horse-power Union Iron Works boilers, equipped with low- and high- water warning whistles, a Jeffrey 150 kw. generator, and a Ridgeway 150 kw. generator. North of the power house is a concrete reservoir hold- ing 3,000bbl. of water, which is pumped from a creek near by. The water is used in the boilers at th© power house. Th© coal is a coking grade, and hence when desired the screenings ar© used in coke ovens adjoining the slack bin. A chute delivers the screenings to a disintegrator, where they are crushed and ©levated by a bucket con- veyor into the slack bin. This bin is 24 ft. by 30 ft. by 52 ft. high, and is constructed of reinforced concrete. From the slack bin the coal is discharged into a larry- car, which carries it to the coke ovens. At the farther end of the ovens from the slack bin and tipple is a crusher for grading the coke into the various commercial sizes. Here the coke is stored in separate bins accord- ing to its size, ready for shipment by rail. * Coal Age. under the discharge from the toothed roll crusher, conveys the coal through an inclined tunnel to the coal plant, the near wall of which is 25 ft. from the centre of the track hopper—a distance determined by the differ- ence in height of the receiving and delivery ends of the belt conveyor. At the delivery end of the belt a 24 in. by 22 in. magnetic separator pulley removes any iron brought along with the coal, and the coal is then discharged into a pair of 24 in. by 18 in. corrugated rolls driven by the conveyor motor. From the corru- gated rolls the crushed coal is raised in an elevator, discharged into a screw conveyor and carried along to a bin (capacity 40 tons) over the rear end of the drier, which enables five hours’ supply for the drier to be stored. The elevator and screw conveyor are both run by one motor. Conveying Machinery. From the bottom of the bin a screw conveyor feeds the coal to the rear end of a 4| ft. by 30 ft. indirect- fired rotary drier, both being run by one motor. The coal passes through the drier and is discharged to an elevator at the front end. A screw conveyor, situated in the floor, also carries the tailings from the settling chamber beneath the drier stack to the elevator. The dried coal and tailings are elevated, discharged into a screw conveyor, and carried to the bin over the two pulverisers. This bin is high enough above the mills to enable all the coal to be fed to them by gravity, and has a capacity of 45 tons. The elevators and conveyors over the bins are operated by one motor. The pulverised coal is delivered by spouts from the pulverisers to an elevator and is raised to a screw con- veyor which carries it to the boiler-house. The conveyor and elevator are both operated by one motor. This conveyor is carried on a bridge 30 ft. long, between the coal plant and boiler-house, and continued through the entire length of the power-house over the bins in front of the boilers, thus making a single straight-delivery unit about 216 ft. in length from coal plant to bins. The bins, one of which is placed in front of each pair of boilers, are rectangular in shape, but have divided hopper bottoms, thus enabling the coal to be fed by separate feeders to each boiler. Each half of the bin with its hopper bottom will hold 10 tons of pulverised coal, or sufficient per boiler for a run of 20 hours at full capacity, so that delays in the coal mill proper will not interfere with the continuous operation of the boilers