February 22, 1918. THE COLLIERY GUARDIAN 381 tubes were then allowed to stay for half an hour on the balance before weighing. The error was probably within a milligramme. Results of the Experiment. Table 1 presents a summary of the data of gas volumes and weights of water and coal obtained. The relations between volumes of gases and weight of water evolved by the coal as given in this table are shown graphically in fig. 2. Table 2 gives the analyses of the coal before and after the experiment. Table 1.—Summary of Data. No. of tests. Kind of gas used. Volume of gas at atmospheric conditions. Weight. Coal. Change in weight during test. Water evolved during test. Remarks. Used in test. Total used. Total. Per litre gas. Total. Per litre gas. Ito 17 18 „ 25 26 „ 36 37 „ 41 42 „ 53 54 & 55 56 to 65 66 „ 75 Nitrogen Do. ... Air Nitrogen Do. ... Air Nitrogen Air Litres. 495’3 560 105.0 33-7 119-0 98-0 505-0 449’2 Litres. 495-3 551’3 656-3 690’0 809’0 907’0 1,412-0 1,861-2 Grins. 263-347 263-887 262-789 262-664 262 914 262’391 262’865 Mgrms. + 540 (?) -125 + 250 -523 + 474 Mgrms. + 5-14 (?) -1-05 +2-55 -1*04 + 1’06 Mgrms. 87-6 164-7 58*0 200’7 166’5 577 3 459-2 Mgrms. 1-56 1’57 1-72 1-69 1-70 1-25 102 Some coal lost through accident. Test 58 omitted in figur- ing H2O per litre of gas. Tests 69 and 70 omitted in calculations. Table 2.—Analyses of the Coal Used. Before experiment. After experiment. ( ( A Coal, Coal, Coal, moisture Coal, moisture air dried and air dried. and ash free. ash free. Air-drying loss, percent. 0’5 — ... 1-1* — Proximate analysis Moisture .... percent. 1’55 . — ... 1-94 — Volatile matter do. ... 37’00 . L*.’ 40‘00 ... 36’36 39-19 Fixed carbon do. ... 55’51 . .. 60 00 ... 56‘43 ... 60’81 Ash do. ... 5’94 . — ... 5-27 — Total 100-00 . .. 100-00 ... ioo-oo ... 100-00 Ultimate analysis:— Hydrogen ... per cent. 5’35. 5’61 ... 5-34 ... 5-53 Carbon do. ... 77’00 . .. 83’23 ... 76’91 ... 82’90 Nitrogen do. ... 1’58 . 1’71 ... 1 54 ... 1’66 Oxygen do. ... 8’96 . 8-18 ... 9-79 ... 8’67 Sulphur do. ... 1'17 . ... 1’27 ... 1’15 ... 1-24 Ash do. ... 5'94 . — ... 5’27 — Total ........... 100-00 ... 100-00 ... 100'00 ... 100’00 Calorific value:— Determined ........... 7,703 ... 8,326 ... 7,651 ... 8,246 Calculated from ulti- mate analysis ...... 7,706 ... 8,335 ... 7,660 ... 8,260 * Gain. Discussion of the Results. When nitrogen was passed through the coal, there was invariably a loss in weight. The loss, however, was-much less than the weight of water evolved from the coal. Hillebrand and Badger found a similar dis- crepancy which they could not explain. The small amount of oxygen in the nitrogen used by the authors is much insufficient to account for the discrepancy observed. They suggest as a possible explanation that it may be due to absorption of nitrogen by the coal which has been shown to occur. When air was passed through the coal there was always a gain in weight despite the loss of water. Comparison of the analyses, on a moisture and ash- free basis, of the coal before and after the experiments shows the increased proportion of oxygen and the corresponding decrease in other constituents. No loss of hydrogen from the coal substance can be shown by the analyses. The vapour-pressure curve, as shown by the graph, fig. 2, follows the same regular course regardless of whether air or nitrogen was passed over the coal, and the coal became gradually drier throughout the experi- ment No evidence is afforded that water is produced by the oxidation of coal at ordinary temperature. Conclusions. (1) There is a lack of agreement between the weight of water evolved by coal and the loss of weight when dried in an inert atmosphere. The excess weight of the coal may be due to absorption of gas. (2) A study of the vapour tension of water in coal, as indicated by the water removed by a regulated current of dry nitrogen and air used alternately, shows no production of water by the oxidation of coal at ordinary temperatures. Dr. Ripper has succeeded to the office of Vice-Chancellor of Sheffield University. Combination of Wagon Makers. — It has now become known that the combination of wagon makers will include no fewer than nine companies, formal notification of the scheme having been made to the shareholders in the past few days. The intended combination is largely due to shortage of labour and the extreme difficulty of obtaining materials. The nine undertakings referred to are the Birmingham Railway Carriage and Wagon Company Limited, British Wagon Company Limited, Messrs. S. J. Claye Limited, Gloucester Railway Carriage and Wagon Company Limited, Messrs. Harrison and Camm Limited; Midland Railway Carriage and Wagon Company Limited, Messrs. Hurst, Nelson and Company Limited, Metropolitan Carriage, Wagon and Finance Company Limited; and, as a first step, repairing branches of the different businesses will be brought under one control, the new company being called Wagon Repairs Limited. The chairman of the new company will be Mr. John Macgregor (managing director of the Gloucester Railway Carriage and Wagon Company), and Mr. M. Middleton (director and general manager of the British Wagon Company) will be the manager, and Mr. J. P. Toplis (assistant joint secretary of the North Central Company) will be the secretary. MINING INSTITUTE OF SCOTLAND. At the meeting of the Mining Institute of Scotland held on Saturday, February 9, the discussion was resumed on the paper read by Mr. George Gibb, Glas- gow, on “A Fresh Aspect of Intensive Mining in Thin Seams.” (Colliery Guardian, Aug. 17,1917, p. 304.) Mr. Richard Kirkby (East Wemyss) said that it would be of value if the author would add two other curves to his chart (Fig. II.), namely, one showing the output, and secondly, the number of haulage attendants. Then one would also like to know the comparative cost for ropes and rollers. Quite evidently Mr. Gibb had to deal with seams with rather bad roofs or pave- ments or both, and the new system he had adopted seemed to have made a very considerable difference to his costs. The only question to decide was—would another system prove more satisfactory still ? Although some of those who had discussed the paper seemed to think this system would be suitable to thick seams as well as thin, this was not at all certain. There was no doubt that two of the main factors to be watched in making and keeping roadways were:—(1) the angles which the natural cleavages made in the line of the roadways ; (2) the angles between the line of the roof breaks made by the working and the line of the roads. Mr. Gibson Reid (Glasgow) said that as one respon- sible for the preparation of the plans and sketches which accompanied the paper, he had to point out that what was laid down in the author’s contribution was not a probability but was the result of actual practice. No claim was made that could not be thoroughly sub- stantiated in modern mining practice. No money had been expended in connection with the scheme without sound and common-sense reasons; and no matter from what standpoint they viewed the system it would be found that there would be a substantial saving in the brushing yardage and consequently in the cost per ton. The latter was, of course, the guiding factor consistent with safety in the development of the mining problems of to-day. Mr. George Gibb, in the course of his reply to the discussion, said he would have preferred a more pro- nounced expression of opinion in regard to critical aspects of the paper rather than an assiduous and universal demand for fuller details in relation to method and application. Frankly, he did hope in his future operations to be guided to some extent by their expressed opinions and searching criticism. If the members would accompany him in a short survey of the diagram, he would endeavour by a few explanatory remarks to remove misconceptions and possibly make the atmosphere clearer. In Fig. I. (Plate 1) they had clearly indicated and illustrated fact of the development of the system. On the left side of the plan he had indicated the panels formed at the outset of the out- ward journey. The larger panels on the right side were the later developments which were possible after the repair work in the longwall area had been advanced, airways of larger dimensions made, and their easier maintenance in the newly-formed pillar area fully demonstrated. At this stage investigation had fully supported the preconceived idea that it was possible to form with safety the larger panels. The smaller panels, which were 150 yards long by 100 yards broad, were, in his opinion, well suited for coal cutting and conveying when withdrawal took place, in the event of either or both of these mechanical applications being adopted. As to the fear expressed by some members of pressure being excessive when branching off the side roads, it might seem strange but it was an actual fact that they had experienced less trouble under the system described than in ordinary branching. Indeed, where desirable they carried the side roads further and with less repairs than in ordinary outward longwall. Sudden bursting and heavy creeping which might have been expected had been the exception rather than the rule in their practice. Indeed, the absolute freedom from these things had been the greatest surprise in the whole development. One member mentioned that he had found roadways advanced in this way subject to sudden outbursts and breaks, and he had explained that he had experienced no end of trouble from these causes. He qualified his remarks with some reference to the nature of the subsidence. Unquestionably this was a point which was well worthy of a paper to itself. He (Mr. Gibb) had no inclination to enter into an academic discussion on this phase of the operations, but in the light of the exhaustive data he had accumulated, he had found, so far, no peculiar difficulties or trouble connected with the operations. For the information of the members he might say that he hoped soon to have an opportunity of opening a new pit in this way, where the system would be much improved. Their past errors had been charted, and each item approved of, so as ensure future continuity of efforts and the highest possible result. On the question of outlay he might be permitted to say this, that in a seam of 24 to 27 in. they could usually lay out the panels at a cost not far short of ordinary longwall. Certainly, the initial monetary bill for cabling and machinery, etc., was higher. In the course of the discussion there had been a generally expressed desire for details of cost, and these he did not intend to disclose, as they were the property of the interests he served. In chart No. 2 (plate 1) were to be found the relative figures for the two systems, and they could apply the ratios as they chose to their own practice, and form their own opinions and conclusions as to the results. In regard to the elimination of distant and straggling sections he did not imply that a section two miles away was brought nearer to the shaft by this system. He did, however, aver that the greater accessibility incidental to the system had largely eliminated the disadvantage of distance in their opera- tions. He did not claim that the system under discussion carried as an essential and peculiar privilege the only means of increasing the ratio of producers to adminis- trators, but he did claim that in their own experience, at all events, it far exceeded longwall in that respect. The discussion was closed, and the author awarded a vote of thanks. SUBMARINE MINING IN EASTERN CANADA.* By F. W. Gray. Coal has been mined under the sea for many years in Cape Breton, and, in the future, the bulk of the coal output of this island will have to come from sub- marine territory. In fact, the time is not far distant when the percentage of submarine coal will exceed that of the coal taken from the land areas, taking the province as a whole. The workings of No. 1 Colliery of the Nova Scotia Steel and Coal Company at Sydney Mines are the most extensive under-sea workings, occupying an area of 3 square miles under the entrance to Sydney harbour. The face of the deeps, in 1916, was about If mile distant from the shoreline, and the workings are being further extended through an area leased from the Dominion Coal Company, which will provide the No via Scotia Company with an immediate extension of its submarine workings, and with access to its own areas lying farther out to sea, distant 3| miles from the shore. In the Lingan-Victoria basin, a limited area only of the coal seams is under the land, the bulk of the deposit being submarine. Five collieries are now working on submarine coal here, and others are projected. In the Glace Bay basin the land area is practically worked out, that is, as far as the three upper seams— the Hub, Harbour, and Phalen—are concerned. There are, at present, six mines with workings in sub- marine territory. In the Morien basin the bulk of the deposit is sub- marine; but it is not now being worked. In Inver- ness county, as elsewhere stated, the basins are mainly submarine, although there are some land areas that have not yet been developed. The most notable submarine area is the seaward extension of the Sydney coal field. So far as can be surmised from the geological indications on land, there is no reason to anticipate any abrupt termina- tion of the coal seams, or any limit to their accessi- bility, except those imposed by the difficulties attend- ing the extraction of coal at a point remote from the source of ventilation and mechanical power, among which problems not the least will be the expeditious transportation of the workmen' to and from their work. The balance of probability is for the uninter- rupted continuance of submarine coal seams beyond the physical limits of extraction, but, nevertheless, the exact conditions can only be established by exploration. Available Tonnage. In calculations that have been made as to the avail- able tonnage in these submarine areas, it has been usual to assume three miles from shore as the limit of extraction, but it seems reasonable to assume, from experience in other submarine coal fields, notably the Cumberland coal field on the west coast of England, that it will be found possible to mine coal up to a distance of between five and six miles from shore. How much farther seaward mining can be prose- cuted, only time and actual experiment can demon- strate. An important factor will be the inclination of the coal seams, but so far as the Sydney submarine area is in question, the seams here dip so gently that the actual horizontal distance to be traversed will set limits to extraction before the depth of the cover, or burden of the superincumbent strata becomes too great. One limitation will be the cost of mining, and it may be the first limiting factor to make itself felt. Many interesting problems suggest themselves as likely to arise as the extraction of the submarine areas proceeds, but the mining of the more remote areas will scarcely come within the lifetime of the present generation, whose obvious duty it will be to so prose- cute the work of extraction as not to imperil the accessibility of the remaining submarine coal. The provisions of the Coal Mines Regulation Act of Nova Scotia, relating to submarine mining, are ten- tative, and recognise the impossibility of making rigid rules where so much has yet to be learned from actual experience. The Act gives great discretionary powers to the Commissioner of Mines, and provides that before work is commenced in any submarine area the plans must be approved by the Inspector of Mines. Every new lift or level in a submarine mine is defined as being a new winning, requiring the sanction of the Inspector of Mines. No submarine coal is allowed to be wroung under a less cover than 180 feet of solid measures; but sub- marine passageways may be driven to win coal under not less than 100 feet of solid measures. When there *Canadian Department of Mines, Bulletin No. 14, on “ The Coal Fields and Coal Industry of Eastern Canada.”