February 23, 1917'. THE COLLIERY GUARDIAN. 383 Pig Iron. —- Employment continued good, and was better than a year ago. There was a general scarcity of labour, and output was still considerably restricted, owing to difficulties in the transport of iron ore, lime- stone, and fuel. Returns showed that 292 furnaces were in blast at the end of January, compared with 289 a month ago, and 265 in January 1916. Engineering. — The engineering trades continued extremely busy, and a large amount of overtime was worked. Trade unions, with 266,752 members (mostly in skilled occupations) reported 0-2 unemployed at the end of January, compared with 0-2 per cent, a month ago, and 0’4 a year ago. Iron and Steel Works.—Employment at iron and steel works continued very good, and showed a slight improvement on the previous month; it was better than a year a.go. Shortage of labour was reported from every district. Tin-plate.—The number of mills working at the end of January showed an increase of 13 compared with the previous month, but a decrease of 131 compared with January 1916. The output of the mills was again affected by the restriction of the Supplies of steel bars. The exports of tinned plates and tinned sheets during January showed an increase of 2,267 tons compared with a month ago, and a decrease of 9,756 tons (over 37 per cent.) compared with a year ago. Steel and Galvanised Sheets. — The number of mills working at the end of January showed an increase of 5 as compared with the previous month, but a decrease of 27 on a year ago. Owing to the shortage of steel bars, the mills were only running about four days a week. Nuts, Bolts, Nails, etc.—Nut and bolt makers were fully employed at Birmingham, Smethwick, and Dar- laston and on the Tyne. Tubes. — Employment with tube makers continued very good in the Midlands, with a scarcity of labour. Wire. — Employment with wire workers continued good generally, and a scarcity of labour and materials was experienced in some centres. At Glasgow it was fair. MINING EXAMINATIONS: SUCCESSFUL CANDIDATES. The following list of successful candidates at the examination held by the Board for Mining Examina- tions on November 21 and 22, 1916, has just been issued :—■ For a First-Class Certificate of Competency as Manager of a Mine. Messrs. N. S. Auckland, H. Bailey, J. Barker, T. B. Bassett, S. Beamand, R. C. Blackbird, W. Bonsall, R. Brown, W. C. Carpenter, W. H. Coe, J. E. Davenport, A. L. G. Davies, G. Davies, J. T. Davies, J. Duckworth, V. S. Dufton, H. Eager, J. L. Evans, W. W. Finn, W. Grier, A. Holmes, C. Hynd, G. Jones, J. Jones, W. Jones. W. H. Lee, B. Lord, F. Mawson, M. D. Moore, W. Moseley, F. P. Newell, D. S. Newey, R. Payne, B. R. Phillips, R. Potter, A. Riley, R. J. Thomas, R. H. Tim- pany, W. L. Varty, and W. Williams. For a Second-Class Certificate of Competency as Under- Manager of a Mine. Messrs. N. Ball, W. A. Barton, G. V. Beardsail, A. Beacham, E. J. Bedson, G. H. Bell, J. T. Boilington, J. Bone, T. L. Bonnell, J. Bourton, G. W. Brooke, J. W. Brough, W. A. Buckley, A. Caddy, R. Carson, A. T. Clark, A. Collins, T. Connelly, S. J. Cross, M. Dakin, D. Davies, D. J. Davies, J. Davies, L. Davies, M. L. Daws, R. T. Dodd, 0. Duncombe, I. Evans, 8. Evans, W. Evans, E. B. Flint, J. Forbes, D. W. Fox, W. J. B. Gair, J. Gemmell, E. Gerrard, J. Goodenough, A. W. Hadley, I. Hampshire, H. C. Handy, E. T. Hanaby, W. Harrison, A. M. Hendry, H. Hindley, W. G. Hogg, F. W. Holdway, S. Hughes, S. J. Jones, S. Lawrence, D. C. Lewis, H. Lister, J. McArthur, N. M. McGowan, T. McGuire, F. Mellard, J. Miller, A. Moffatt, H. Murray, A. F. Nairn, H. R. New- bury, T. J. Oakley, O. J. Onions, A. Orr, E. A. Parker, L. Parry, F. Peel, J. Pimblett, E. Powell, A. McC. Pren- tice, J. R. Prentice, D. Reston, J. T. Rice, W. Robertson, J. W. Sanders, J. D. Sanderson, W. Scott, H. Senior, C. W. J. Sexton, H. Sharpies, W. B. C. Sharp, G. Simpson, J. Splitt, J. Stafford, G. Steven, I. M. Thomas, R. Thomas, C. Thompson, A. Townend, G. H. Wagstaff, T. I. Walters, A. Ward, H. Westwood, G. W. Whitfield, ■J. H. Wightman, J. Wilkins, E. W. Williams, H. Williams, H. Wootton, and L. Yates. For a Certificate of Qualification as Surveyor of Mines. Messrs. J. W. Bailey, L. Black, J. St. C. Bowden, H. R. Boyd, J. G. Clennell, A. Coldwell, C. 0. Cooper, C. C. Cowling, A. Davies, T. P. Davies, S. Davis, F. A. Dixon, J. H. Douglas, T. Eden, R. J. Edwards, F. S. Egan, E. M. Green, S. E. Hayes, J. Hissett, E. N. Holden, J. Jackson, W. A. Jones, G. Kean, junr., W. McDonald, A. Mack, G. Neath, T. Ovenstone, E. Procter, R. A. Robertson, A. Soargill, A. Simpson, T. H. Stonehouse, S. H. R. Strang, R. D. Taylor, E. Trotter, J. Turnbull, C. E. Twist, J. C. Tyler, J. Van Loon, C. G. Villis, J. E. Waring, E. Williams, Hi I. Williams, and T. J. Yorath. Hydraulic Filling in Illinois Mines.—Under the co-opera- tive agreement of the Bureau of Mines with the State of Illinois, investigations into mine subsidence and roof sup- ports have been made. The problem is of great and increas- ing importance in Illinois, because so much of the coal underlies rich agricultural land, where subsidence results in ponds and marshes. In many oases drainage is reversed or destroyed. Damage has been caused in towns built above the mines. The problem is complicated by the fact that the value of the surface land ranges up to 250 dols. an acre, which is several times the value of the coal in places. The question of subsidence in Illinois is related to that of improved mining methods looking ultimately to the intro- duction of filling methods, such as hydraulic filling used so extensively in Germany. ELECTRIC SIGNALLING IN MINES. Telephony is one of the electrical utilities which has justified itself in colliery practice, and its application under the most varied conditions is exemplified in the productions of the General Electric Company Limited, 67, Queen. Victoria-street, London. The system referred to is known ais the G.E.C. mining telephone, one of the new forms of signalling gear originated by the company, for mining work. Severe tests applied to it in practice prove its compliance with the regulations, and it may be regarded now as representing a recognised feature of modern equipment. Complete safeguards are provided. I A .1 ■ . ’ Em Fig. 1.—G. E. C. Mining Telephone. For telephonic communication between various parts of the pit, it is essential that the instrument complies fully with the special requirements of colliery work. Much of the apparatus hitherto used has been different in this respect, but the General Electric Company has designed a flame-proof mining telephone, which is now used by a number of collieries. The telephone com- prises a four-magnet tropical type generator, operated « Fig. 2.—Interior View of Davies-Railing Relay. by a strong handle worked through a flame-proof and watertight gland. The ringing movement is polarised. A general reference to electrical signalling recalls the danger of sparking which attended the old system of wires along the road. To obviate this danger, the Davies-Railing system was introduced, with the result that repeat orders have demonstrated its satisfactory Fig. 3.—Indicator Showing Signal. lower HEN ' . i \ k - ’■ ' i 9* character. Instead of permitting a spark to occur at the signalling point, this system provides a relay circuit, and the bell circuit is made and broken inside an explo- sion-proof box. This is a purely local contrivance, and distinct from the signalling wires. The operation of the ball is effected through the relay, which is so delicately poised that it requires a current of merely telephonic dimensions to actuate it. The cun-ent is derived from a three-volt battery, and the cumulative effect of the various precautions removes all possibility of danger. Exhaustive tests taken in a colliery gas testing station failed to elicit any visible spark at the point of contact between the signalling wires. Other advantages are claimed on behalf of the system. For instance, practi- cally no change is involved in any existing installation, nor any alteration made in the mode of signalling, nor any limit fixed to the length of signalling wires. The obvious simplicity of working the apparatus is another point in its favour. In the case of signalling between onsetter and pit bank, the .system under notice has been installed in a number of collieries in South Wales. As compared with the method of mechanical signalling, ths operator simply pushes a button instead of pulling a handle or wire. Use is made of indicators for the engine room, a bell for the banksman, and another bell for the onsetter. Two indi- cators—audible and visible—are recommended for the engine room. As each signal is kept standing until the next is delivered, a useful purpose is served if any ques- tion occurs a.s to the preceding signal. The mainten- ance cost of the apparatus is said to be negligible. OUTPUT AND VALUE OF FUEL IN 1915.* The total value of the minerals raised during the year amounted to £170,460,949, an increase of £24,597,917 as compared with 1914. The total output of coal was 253,206,081 tons, and the value £157,830,670, showing a decrease in the output of 12,458,312 tons and an increase in the value of £25,233,817 on the figures for 1914. The average price of coal was 12s. 5’60d. per ton in 1915, as compared with 9s. ll-79d. in 1914. The quantity of coal exported, exclusive of coke and manufactured fuel and of coal shipped for the use of steamers engaged in foreign trade, was 43,534,560 tons. France received over 17} million toils, Italy over 5| million tons, Denmark over 3 million tons, Sweden over 2} million tons, Norway over 2} million tons, the Nether- lands over 1| million tons, the Argentine over 1} million tons, Spain over 1} million tons, and Egypt over 1| million tons. Adding the 2,786,401 tons exported in the form of coke and manufactured fuel, and the 13,630,964 tons shipped for the use of British and foreign steamers engaged in foreign trade, the total quantity of coal which left the country was 59,951,925 tons, as against 80,993,890 tons in 1914. The amount of coal remaining for home consumption was 193,254,156 tons, oir 4-193 tons per head of the population; 37,284,600 tons were used in the manufacture of coke and briquettes, and 2,509,456 tons of coal with 9,746,743 tons of coke (equal to 16,244,572 tons of coal) in the blast furnaces for the manufacture of pig iron, as against 36,289,010 tons and 18,381,106} tons respectively in the previous year. During the past 43 years (1873-1915) the total value of the mineral raised amounts to £3,835,441,023, and of this sum coal accounts for £3,241,021,908, or 84-5 per cent.; 8,459,449,000 tons of coal have been raised in that period; and of this amount 2,072,747,000 tons, or more than 24} per cent, of -the total production, have been shipped abroad as exports in the form of coal, coke, and manufactured fuel, and as coal used for steamers engaged in foreign trade. The following are the percentages of output shipped abroad in each quinquennial period from 1873 to 1912, and the percentage for the years 1913, 1914, and 1915 :— 1873-77, 13-8 per cent.; 1878-82, 16-1; 1883-87, 19-0; 1888-92, 21-2; 1893-97, 23-0; 1898-1902, 25-7; 1903-7, 29-5; 1908-12, 32-4; 1913, 34-2; 1914, 30-5; 1915, 23-7 per cent. Particulars relating to the manufacture of coke and briquettes are given; 20,059,140 tons of coke were obtained in 1915, valued at £18,270,018; 16,574 coking ovens were in use during the year; 1,697,541 tons of briquettes were produced, valued nt £1,755,406. Of the other non-metallic minerals, the combined values of the output of clay and shale, igneous rocks, limestone, oil shale, salt, sandstone, and slate for 1915 amount to over 6} millions sterling. Of the metallic minerals raised in the United Kingdom, iron ore is by far the most important. During the year the output of iron ore was 14,235,012 tons, valued at £4,587,651. The ore yielded 4,567,351 tons of iron, or more than half of the total quantity of pig iron made in this country. The following table gives a summary of the total output of coal for each country of the United Kingdom : From From Total Comparison Country. mines, quarries. ' with 1914. Tons. Tons. Tons. Tons. England ........ 178,029,226...26,635...178,055,861.. - 6,489.716 Wales .......... 39,468,807... ... 39,468,807...- 2,710,247 Scotland ....... 35,596,856... — ... 35,596,856...- 3,250,506 Ireland ............ 84.557... — ... 84,557...— 7,843 Total 1913.. 253,179,416...22,635...253,206,081... -12,458.312 Total 1914.. 265,643,030...21,363...265,664,393.. -21,766,080 The total value was as follows : England, £105,404,560; Wales, £30,552,875: Scotland, £21,817,302; Ireland, £55,933 — total, £157,830,670, as compared with £132,596,853 in 1914. * From Part III. of the General Report on Mines and Quarries for 1915; edited by Sir Richard Redmayne, H.M. Chief Inspector of Mines. f Previous to 1915 the actual quantity of coke used was not furnished. This figure therefore represents the coal used and the equivalent in coal of coke used.