334 THE COLLIERY GUARDIAN. February 16, 1917. 'THE COKE INDUSTRY OF NEW SOUTH WALES.* By L. F. Harper and J. C. H. Mingaye. (Continued from page 281.) Wallsend Coke Works. The Wallsend works of the Purified Coal and Coke Company were established in 1877, but have been enlarged and brought more up-to-date as opportunity offered. The coal used is from the Borehole seam, as worked at Wallsend Colliery, and gives the following analysis, the bands being picked out; the coke is slightly swollen, firm, and lustrous; and the ash buff-coloured, Bemi- granular. Per cent. Hygroscopic moisture............ 1'04 Volatile hydrocarbons ........... 35'27 Fixed carbon..................... 53'10 Ash.............................. 10'29 100'00 Sulphur ............................ 0'488 Specific gravity................... 1'376 Coke ............................. 63'69 > Calorific value (lb.)............. 12'4 I Under normal conditions slack coal only is used, but at the present time, owing to depression in the coal trade, due to export restriction, about two-thirds large coal is used. After having been screened at the colliery and delivered in hopper wagons to the coke works, the slack is mechanically conveyed to the washery direct, whilst the large is first passed through a Gates rock breaker and fed to rolls. It then joins the slack, Bind all is passed through a washery consisting of four pulsating vats, the washed coal passing over lips into a system of troughs with a mechanical restrainer, con- sisting of an endless belt fitted with copper paddles, revolving in the opposite direction to the flow of coal- laden water. A large proportion of the water drains off through the bottom of these troughs, so that on reach- ing the third one an accelerator is used, similar in design to the restrainers, but the copper paddles act as scrapers, revolving in the direction of the discharge. As the water passes through the bottom of the troughs, it removes a portion of the coal sludge, and this is fed back into the slack hopper, to again pass through the previous process. This does away with any Loss of coal, but would appear to increase the quantity of material pass- ing through the disintegrator and washery to an unneces- sary extent. The slack coal used contains a proportion of colliery refuse, and naturally a much higher ash percentage is pre- sent than in the large coal. This is considerably reduced by the washing process, as evidenced by the two following analyses :—Slack coal as fed to the washery : Hygroscopic moisture, 1-92 per cent.; volatile hydro- carbons, 35-58; fixed carbon, 48'81; ash, 13'69; coke, 6'2'5 per cent. Ash, dark grey in colour, semi-granular. Coke, well swollen, firm, and lustrous. Sulphur in coal, 0'549. Prepared washed coal as fed to the coke ovens: Hygroscopic moisture, 1-94 per cent.; volatile matter, 35-90; fixed carbon, 52'24; ash, 9'92; coke, 62-16 per cent. Ash, dairk grey in colour, semi-granular. Coke, well swollen, firm, and lustrous. Sulphur in coal, 0'439. In actual practice, it is estimated by the management that the ash percentage is reduced by 10. From the washery the coal is fed to the disintegrator, and passes through into the canisters ready for charg- ing, the time occupied in the whole process being about three minutes, and moisture left in the duff amounts to approximately 9 per cent. The ovens are of the bee- hive pattern, and 76 in number, arranged back to back, with the following dimensions : 11 ft. in diameter, and 7 ft. 3 in. high to the crown of the arch. The duff charge weighs about 7 tons, and is filled from the top by means of canisters moved on rails by gravity when full, the empties being returned to the hoppers by a steam-worked endless rope, with a self-detaching Clip arrangement. The ovens are burnt in 80-hour periods, at a maxi- mum temperature of 1,500 degs. Fahr., and the air supply is provided by a system of horizontal flues, which cause it to pass completely round the coking bench before admission to the oven, a temperature of sbout 800 degs. Fahr, being thus reached before coming into use. The coke return is estimated at 48 per cent., and after internal quenching it is withdrawn by hand. The necessary power is provided from an automatic feed 200 horse-power Babcock and Wilcox boiler, whilst the water supply is obtained from a local dam or the Iliver Water Supply Service; 45 men are employed at the works, and during the year 1915, 21,144 tons of coke were made from 44,000 tons of coal gross. An analysis of the coke gave the following result :— Hygroscopic moisture, 1'16 per cent.; volatile matter, 0-74; fixed carbon, 84'36; ash, 13'34; sulphur, 0-40 per cent. Specific gravity, 1-754. Ash, reddish tinge, semi-flocculent. The ash contained : Moisture, nil; silica, 57'24 per cent.; alumina, 24'81; ferric oxide, 11'20; lime, 2'52; -and sulphur trioxide, 0-26 per cent. For special purposes a coke is made from a mixture of Jesmond coal and Mount Pleasant coal (Borehole seam and Bulli seam), and a sample of this coke was analysed, with the following result : Hygroscopic moisture, 0-69 per cent.; volatile matter, 0-99; fixed carbon, 87'76; ash, 12'15; sulphur, 0'41 per cent. Specific gravity, 1'793. Ash, slight reddish tonge, flocculent. The ash contained : Moisture, nil; silica, 52-56 per oenlt.; alumina, 28-65; ferric oxide, 11-30; lime, 2-78; and sulphur trioxide, 0-35 per cent. Co-operative Colliery and Coke Works. The works (established about 1875) are situated at Plattsburg—or Wallsend, as the village is now called— * New South Wales Department of Mines, Mineral Resources. No. 23. about half a mile from the Wallsend Company’s rail- way, to which they are connected by a siding. The colliery and coke works adjoin, and the coal used is won from -the Borehole seam, two samples of which analysed as follow; in both cases the bands were picked out, whilst the coke was fairly swollen, firm, and lustrous; and ash, buff-coloured, semi-granular:— Per cent. Percent. Hygroscopic moisture .-. .... 1-84 .. 1'71 Volatile hydrocarbons ... ... 36’10 .. . 36'60 Fixed carbon .... 55'99 . . 56 22 Ash . .. 601 .. 5'47 100'00 . . 100'00 Sulphur 0*576 .. 0'535 Specific gravity 1'311 . 1'317 Coke ... 62'00 .. . 61'69 Calorific value (lb.) ... 13'2 . 13'2 Both large and slack coal are being used at the present time, .but washing has not been found necessary, in view of the low ash percentage in the coal. The nature of the coal enables a marketable coke to be made without undergoing a disintegration process, and large coal is sometimes used in the ovens, but the greater portion is first passed through a Carr disintegrator. The ovens, 67 in number, are of the old beehive type. Six pairs are built back to back, the remainder forming three sides of a rectangle, the central space being used as a coke bench. They range in size from 10 to lift, in diameter, and from 6ft. 7 in. to 10ft. from the floor to the crown of the dome. The six pairs have over- head feed ports, and are encased in dressed stone, whilst the remainder are built entirely of locally-made bricks, and shovel-filled from the door, the coal being wheeled by hand from the screens or disintegrator to the ovens. The charge varies in weight from 4 to 6 tons, accord- ing to the size of the ovens, and the period of burning is three days throughout. Internal quenching is adopted, the Hunter River Water Supply Service being used. It is estimated that the coke yield is 55 per cent., and the loss after- withdrawal under 1 per cent. Only 44 ovens are now in use, 14 men being employed, and the output for 1915 was 7,161 tons of coke, produced from 13,020 tons of coal, or 54-92 per cent. Fig. 4.—Messrs. G-. and C. Hoskins’ Coke Ovens, Lithgow (N.S.W.). An average sample of coke analysed with the following result:—Hygroscopic moisture, 1'67 per cent.; volatile matter, 1-02; fixed carbon, 84-98; ash, 11-99; sulphur, 0-34 per cent. Specific gravity, 1-724. Ash, buff- coloured, flocculent. Coke, light grey in colour, firm, light, and not readily broken on handling. An analysis of the ash from the coke gave the following result :— Moisture, nil; silica, 56-96 per cent.; alumina, 30'65; ferric oxide, 7-05; lime, 0-82; and sulphur trioxide, 0-09 per cent. The Rix’s Creek Coke Works. These works, owned by the Great Cobar Copper Com- pany, are situated on Rix’s Creek, abour four miles from Singleton, and 52 from Newcastle. The necessary coal is obtained from Rix’s Creek Colliery, adjacent to the ovens, but the exact horizon of the seam being worked has not hitherto been definitely determined, though it is believed to be identical with the Borehole seam of the Newcastle district, for not only is the coal admirably adapted for coking—a distinctive feature of that seam, as opposed to other Newcastle- coal horizons — but the number of included bands correspond closely, and it is the same relative height above the top of the upper marine series. The following is an analysis of the- Rix’s Creek coal, the bands being picked out, whilst the coke is slightly swollen, firm, and lustrous; ash, buff-coloured, semi-granular :— Per cent. Hygroscopic moisture ............ 2'60 Volatile hydrocarbons ......... 38'42 Fixed carbon ................... 51'21 Ash............................. 7'77 100 00 Sulphur ........................ 0'574 Specific gravity................ 1’275 Coke ........................... 58 98 Calorific value (lb.)........... 12 7 At the present time the total output of the colliery is used at the coke works, the full run-of-mine being charged direct into the ovens, without either washing or disintegration. Although the miners are supposed to hand-pick the coal, only the more prominent bands are rej-e-cted, with the result that a high percentage of dirt is fed to the ovens with the coal. Much iron pyrites is also present, occurring principally on the joint faces, so that there is ample room for improving the charge bv washing. The ovens, 12 ft. in diameter, and 6 ft. high to the crown of the dome, are of the old-fashioned beehive type, 26 in number, and built back to back in one stone-faced bench. The periods of burning are 72 and 96 hours respectively, the weight of the charge, which is fed by manual labour from hoppers into a port in the crown of tile oven, being 5 tons in each case, and yielding 58 per cent, of coke. Internal quenching is adopted, and is more or less con- fined to the upper surface or face only, and the imper- fectly quenched coke is withdrawn by hand, and wheeled into the coke bench, ready for loading into railway trucks. The quenching is far from adequate, for the coke is very often dully glowing when landed on the bench, and increased loss in ash from burnt coke results. Moreover, the coke has a natural tendency to “ finger,” with the result that the percentage of “ breeze ” is high. The maximum weekly output would be 150 tons, but the present average is only 110 tons; eight men being employed. Analysis of the coke shows it to contain :— Hygroscopic moisture, 0-44 per cent.; volatile matter, 0'60; fixed carbon, 86'98; ash, 11-54; sulphur, 0-44 per cent. Specific gravity, 1-745. Ash, slight reddish tinge, flocculent, and containing: Moisture, 0-06 per cent.; silica, 53-70; alumina, 28-72; ferric oxide, 8'30; lime, 2-76; magnesia, 1-40; and sulphur trioxide, 0-11 peir cent. Eskbank Coke Works. The Lithgow Iron Works (G. and C. Hoskins) have -a coking plant in connection with their blast furnaces, established in 1912. The coke ovens are about one mile distant from Eskbank Station on the Main Western line, 95 miles from Sydney. The coal used is obtained from the Lithgow seam, as worked at the Oakey Park Colliery, distant about 11 miles from the ovens. A most noticeable feature with regard to coal from this seam is that, whilst the Oakey Park product is admirably adapted for coking, coal from the same seam in adjoining collieries possesses very inferior coking properties, or is entirely unstated to coking. The coal is delivered at the coke works in hopper wagons, and fed to a breaker consisting of a horizontal toothed roll, revolving between heavy but not rigid steel aprons. This reduces the coal to a maxi- mum diameter of about 21 in., and the roughly-crushed coal is raised directly to the storage bins by means of a scraper elevator, or first reduced in a disintegrator. The ovens (fig. 4) are of the Bel- gian type, 78 in number, with bottom flues only; but an addi- tional 15 are being erected with both -side and bottom flues. They ■are built on the rectangular bee- hive pattern, with a low angled gable roof, and the following dimensions : Length, 30 ft.; width, 5 ft.; and 5 ft. high to the ridge. The ovens are charged from canis ters into two ports, arranged so as to distribute the coal on either side of the port, the weight of coal fed to each oven being about 10 tons, and the burning period 50 hours. A somewhat curious phenomenon occurs in the bottom flue ovens, the lowest portion (9 in.—12 in. in depth) of the block of coke refusing to cake, and being therefore useless by reason of its tendency to “ pack ” in the blast furnace, through inability to bear the weight of the charge. It has been suggested that the trouble is due to a.n increased ash percentage in the charge within the zone -affected, for it is well known that an increase in the ash contents will often prevent caking. The increase would be brought about by the gravitation of the shaly material (having a greater specific gravity) to the oven sides, but reaches the angle of repose before touching the wall, and thus a zone occurs along either side of the charge which contains more than its due per- centage c-f ash, thereby retarding or preventing coking. The oven doors are -raised by hydraulic power, the coke is discharged by a steam ram, after internal partial quenching, and is finally thoroughly watered on, the coke bench, about 4 per cent, of waste resulting from breeze -and ash; 30 men are employed, and the maximum weekly output is 1,250 tons. The generated gases are used in the oven flues only, but from the 15 new ovens the gas will be utilised for geneira-ti-ng steam or power purposes. Samples o-f the coke have been analysed, with the following results :—Hygroscopic moisture, 0-68—1-2 per cent.; volatile matter, 1-1—1-18; fixed carbon., 80-08— 80-1; ash, 17'42—17-6: sulphur, 0-45—0-64. Specific gravity, 1-775. Ash, dark grey in colour, semi-floccu- lent, and containing: Moisture, 0-08 per cent.; silica, 54-60: alumina, 31-99: ferric oxide, 7-25; lime, 0-60; and sulphur trioxide, 0'02 per cent. The Oakey Park Goke Works. The Oakey Park Coal and Coke Company lias been producing coke for about 12 years at works situated near Oakey Park Junction, 92 miles from Sydney. The necessary coking coal is obtained from the Lithgow seam, as worked in the company’s own colliery adjoin- ing the coke ovens, and as a rule slack only is used, although provision is made for breaking and grinding large coal when required. Two analyses of coal from this colliery are given below, the bands being picked out, and the coke well swollen, firm, and lustrous.