228 THE COLLIERY GUARDIAN. February 2, 1917. THE COKE INDUSTRY OF NEW SOUTH WALES.* By L. F. Harper and J. C. H. Mingayb. . Though no official record of the first manufacture of coke in New South Wales was kept, it would appear that the first ovens were erected at Duckenfield Colliery, Miami, about the year 1861, 'the coal used being won from the Borehole seam. There were 32 ovens, two rows of 16 each, built back to back. They were circular inside, and flat-bottomed, the side walls being straight up for about 3ft. or 3ft. 6in., and then domed over. There was a round chimney, 18 in. in diameter at the top, and the diameter of each oven was 9 ft. The height of the oven inside was 6 ft., and the outside walls were built straight up, and the top was flat, to enable work- men to walk about on them when necessary. In the front of each oven there was a doorway or opening 3 ft. 6 in. high, and 2 ft. 3 in. wide. The charge was a wagon load (seven tons) of small coal direct from the screens. The bottom of the wagon was let down, and the small coal allowed to run on to the ground in front of the oven door or opening. It was then shovelled into the oven, and the opening built up with bricks and mud, small openings being left for draught. At the end of five days the small openings were closed, and a damper put over the chimney. The oven was left in this sealed state for three more days, when the bricks in the door- way or opening were taken out (the damper being left . on the chimney), and the coke withdrawn by means of a long iron rod with two prongs turned down at one end. The damper was left on top of the chimney while the drawing was being done to prevent the coke burning up again. The coke was red hot when taken out of the oven, and no water was used to cool it, but it was spread on to the platform to cool, and then stacked. . Opera- tions ceased at these coke ovens in June 1898, and they were pulled down about two or three years ago. About the year 1875 or 1876, a small coking plant was established at Plattsburg, near Walfeend, in conjunction with the Co-operative Colliery, which is winning coal from the Borehole seam of the Upper or Newcastle-Built coal measures. The number of these ovens has been greatly increased, and they are still running. In 1877, coke ovens were erected by the Purified Coal and Coke Company at Wallsend, the coal being also obtained from the Borehole seam. This company is a large coke producer even at the present day, but the plant has been greatly improved, and the number of ovens increased. The first coke ovens in the Illawarra district were built by Messrs. Osborne and Ahearn in September 1878, and were worked by them until June in the follow- ing year, after which they were carried on more success- fully by Mr. W. M. Ashley. The ovens, four in number, and of the beehive type, were erected near 'the Wollon- gong wharf, the small coal being obtained at a very nominal sum from the Mount Keira Colliery. A few- years later Mr. Thos. Bertram, one of the proprietors of the Corrimal Coal Company, built seven ovens near the colliery, and worked them several years wdth indifferent results, when they were closed down. It was not until the year 1888 that the industry, on a large scale, became a commercial success, when the Australian Coke Making Company Limited built 20 ovens of the Welsh type at Unanderra. For some years there was considerable prejudice amongst the consumers against the locally-made article, which was eventually overcome, and the Australian Coke Making Company Limited subsequently added a further 72 beehive ovens to their plant, making a total of 92, which were worked until they were out of date in 1912. Messrs. G. S. Yuill and Company Limited then erected 40 ovens of a larger type at Corrimal. Following the lead of the Australian Coke Making Company Limited, Messrs. Robshaw- and Figtree (now Figtree Brothers) built ovens at Mount Pleasant; then the Bulli Coal and Coke Company Limited, the South Clifton Coal Mining Company Limited, and the Mount Lyell Mining and Railway Company Limited, at Port Kembla; the Broken Hill Associated Smelters Proprie- tary Company Limited, at Bellambi; the Federal Coke Company Limited, at Mount Keira; the North Bulli Colliery Limited, at Coledale, erected coking plants; and the Illawarra Coke Company Limited, at Coal Cliff, so that from four small ovens in 1887, the industry has grown to its present proportions, there being now over 530 ovens in the district of a modern type, except at one works, with a possible annual output of about 350,000 tons. Coking Coals. The principal seams from which good coking coal is at present being obtained in New South Wales are : (1) The Borehole seam, in the Northern coal fields; (2) the Bulli seam, in the Southern field; and (3) restricted areas of the Lithgow seam, in the Western field. The first-named seam occurs near the base of the Upper or Newcastle coal measures, the second at the very top of the same measures within the Southern field, whilst the latter is the lowest seam within the Western coal field. The Borehole seam yields a coking coal wherever worked. The Bulli seam coal is more or less adapted for coking throughout, with the exception of its extreme northern extension within the Illawarra coal field, but the areas of good coking coal within the Lithgow seam are for more restricted, and whilst one colliery will yield H coal admirably adapted for that purpose, the product from an adjoining colliery may be practically useless. Seams Nos. 2, 3, and 4, within the Southern coal field, undoubtedly yield an excellent coking coal, but up to the present, only the- former has been utilised, and that to a very limited extent. This is due largely to the fact that within the area at present operated on by working collieries, seams Nos. 3 and 4 are negligible by * New South Wales Department of Mines, Mineral Resources. No. 23. reason of the dirty nature of the coal, and the large number of included bands. South from Mount Kembla, however, and extending to tire neighbourhood of the Jamberoo Mountains, con- ditions of sedimentation were more favourable, and seams Nos. 2, 3, and 4 undoubtedly have potentialities, even if from a coking point of view only. From the south side of Mount Kembla the Bulli seam deteriorates to such an extent that it ceases to have potentialities as a source of coal supply. Here a local basin or area of deposition is evidenced with regard to seams Nos. 2, 3, ■and 4, with its main axis apparently some few miles west of the Illawarra Coastal Range, and extending from Mount Kembla to the Jambeiroo Mountains. Towards the northern end of this area, seams Nos. 2 and 3 improve very much in quality, whilst in the central and southern portion seam No. 4 becomes an important factor. Up to the present, only the eastern edge of this local basin has been prospected, and the coal is slightly inferior to that obtained from the Bulli seam further north; but, as stated, only the edge of the basin has been prospected so far, and until the central portion has been tapped by means of the diamond drill, the quality of its coal contents must remain in doubt. In any case, existing prospecting operations prove that there are seams in this locality yielding an excellent coking coal, even if washing has to be adopted to reduce the ash percentage. The ash contents is largely present in the form of shale bands, so that good results may be expected from washing, or the use of a picking belt, and moreover the coal is naturally friable, thus lending itself to disintegration. Analyses of coal from the various prospecting tunnels south of Mount Kembla are as follow, the coke in each case being well swollen, firm, and lustrous :— No. 2 or No. 3 or No. 4 or Four-ft. Thick Tongarra seam. seam. seam. Per cent. Per cent. Per cent . Hygroscopic moisture .... 0'94 . 0'30 ... 0'79 Volatile hydrocarbons.... 24'41 . .. 25'85 . .. 26'62 Fixed carbon 63'20 . .. 61'96 ... H0 07 Ash ... 11'45 . .. 11'89 . .. 1.2 52 100 00 . .. 100'00 .. 100'00 Sulphur ... 0'370 0'59 0'65 Specific gravity 1'36 . 1'456 ... 1'355 Coke .... 74'65 . .. 73'85 . ... 72'59 Calorific value 12'8 .. 12'7 ... 12'9 The -best coking results in other parts of the world would appear to result from coal containing about 25 per cent, volatile matter. The average percentage of I Fig. 1.—Ram and Charger, Mount Lyell Coke Works, Port Kembla. volatile matter in the principal coals of New South South Wales is : Upper measures, Northern coal field, 36'01 per cent.; upper measures, Western, coal field, 32-31 per cent.; upper measures, Southern coal field, 23'65 per cent.; lower coal measures, 41'35 per cent. Seams Nos. 2, 3, and 4, south of Mount Kembla, have approximately 24, 26, and 26 per cent, of volatile hydro- carbons respectively. Thus it will be -seen that a mixture of these and the Bulli seam coal would come very close to the desired theoretical percentage of volatile hydrocarbons in a coal most suited for coking purposes. Quite a number of bulk tests of coal from these seams have been made in various coke ovens on the south coast, and according to coke burners the results were most satisfactory, but only three samples were obtain- able a-t the time. There appears every probability, however, that further attention will be paid to this source of coal supply in the near future, and if effective coal washing, or picking, be carried out before coking, results should prove satisfactory. Cokes made from 'the coal seams south of Mount Kembla were analysed, with the following proximate results :—■ South of Mount Kembla. No. 2 No. 3 seam. seam. Per cent. Per cent. Hygroscopic moisture .. .... 1'70 . 0'74 Volatile matter . 1'93 . 0'24 Fix^d carbon .... 86 04 . .. 76'55 Ash .... 9'87 .. 21'99 Sulphur .... 0'46 . 0'48 '■ ■ — 100'00 . .. 100'00 Specific gravity .... 1'805 . 1'926 Ashes, grey in colour, semi-flocculent. Coke, dark grey in colour, dense, hard, and compact. The sample from No. 2 seam is a good quality of coke for metal- lurgical purposes. The coke from No. 3 seam has excellent physical properties, but the ash contents are too high for a good metallurgical coke. Experiments are needed to show what percentage of impurities could be removed from the coal by washing prior to coking. No. 3 Seam, Wongawilli, South of Kembla. Per cent. Hygroscopic moisture ........... 0'68 Volatile hydrocarbons .......... 0'97 Fixed carbon.................. 73'23 Ash........................... 24'59 Sulphur ........................ 0'53 100'00 Specific gravity.................. 1'899 Ash, grey in colour, flocculent. Coke, dark grey in colour, firm, and compact. The large amount of ash in the coke will militate against its use for smelting pur- poses, but it is possible that by washing the coal before coking the ash contents would be largely reduced. No. 3 Seam, South Kembla. Per cent. Hygroscopic moisture .......... 0'75 Volatile hydrocarbons ......... 1 '20 w Fixed carbon.................. 81'55 Ash........................... 16'50 100'00 Sulphur ......................... 0'590 Specific gravity................ 1'801 Ash, buff coloured, granular. This sample was made at the Mount Pleasant Coke Works, and the coal used was more or less cleaned by hand picking, thus indi- cating that by the use of a picking belt, the ash per- centage can be largely reduced. Preparation of Coal for Coking. By far the largest proportion of coal used for coke making in New South Wales is in the form of screenings known as Slack, and ranges in size from coal dust up to fragments the size of a walnut. In 'the case o-f one or tiwo of the coke works, however, run-of-mine coal, i.e., both forge and small, is sometimels used, such being dependent upon supplies available, or the yield of a coke better suited to consumers’ requirements. Generally speaking, crushing a coal before it is charged into ovens improves the quality of the coke produced. Fine crushing makes the distribution of impurities more uniform, and subsequent breakage of the coke is reduced, the coke being drawn in larger pieces. The coke cells are closed, and the product is stronger and better able to carry its burden in the furnace. On the other hand, it is recognised that the ash percentage is increased owing to the intimate mixture of clay band fragments, which would otherwise largely fall away on handling the coke. The relative advantages of either method would appear to be entirely dependent upon the qualities most sought after by the consumer, but it has been thoroughly demonstrated that certain coal will only cake after finely crushing. If run-of-mine coal is used, it is first screened at the colliery, the largest being usually fed into some form of rock breaker. In the ease of Rix’s Creek Coke Works, however, the coal is passed direct from the mine to the coke ovens. The slack from the colliery screens and rock breakers may be either washed to eliminate some of the contained ash, or fed to a disintegrator. Practi- cally the only crusher in use in New South Wales is the Carr disintegrator, in which two reels- mounted on shafts, and running in opposite directions, each consist o-f two concentric rings in which steel spindles 'are fixed from 2 to 3 in. apart. The coal after passing through this machine is in a finely-divided state, the size of the largest individual particles being determined by the ■number of spindles used, and is then known as “ duff." The slack coal may be submitted to a process of wash- ing, but only two coke producers are washing their slack coal at the present time—the Mount Lyell Coke Works and the Purified Coal and Coke Company. Types of Oven Used. Three main types of ovens are in use in New South Wale-s, namely, the true beehive, rectangular beehive, and by-product ovens. The first was the original oven type, the coking was depend-ent upon top heat only, the ovens in New South Wales being 'generally built on the doubl-e-row principle, that is, back to back. There are still a number of these ovens in use, but they are gradually being replaced by