June 5, 1914. THE COLLIERY GUARDIAN. 1239 i i i ' — hS ; i 34—1 F -A 3-Fn Fig 6.-Assumed Section showing Thickness of Magnesian Limestone BETWEEN HoRDEN COLLIERY AND BOREHOLE AT BtACKHALL EE __________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ __________________________________________________________________________________________ ATTUAL H)tlT10N OF 06AL-NU £U3 8T-1IO* p. with cement, 70 tons of which were used during this part of the process, and the feeders were reduced to quite a negligible quantity. Owing to a shortage of coal, due to the miners’ national strike, it was considered advisable to suspend further operations, and therefore work was not resumed until May 20, 1912, when the standing water was again pumped down. The feeder was found to amount to 100 gallons, which quantity gradually increased to 395 gallons per minute when the cement concrete plug was removed. After sinking a further 30 ft. a good crib bed was secured, and a short length of tubbing was fixed, the origmal feeder of 6,400 gallons per minute having been reduced by the method adopted to just under 1,200 gallons per minute. The total amount of cement used was as follows :—For plug, 103 tons 2 cwt.: injected into strata, 71 tons 18 cwt.; injected behind tubbing, 26 tons—total 201 tons. It was interesting to note that in sinking through the limestone below the cement plug all the large fissures were filled with strong, well-set cement: and there is no doubt whatever that, if greater care had been taken with the method adopted, the feeders of water could have been reduced to quite negligible quantities; but, on account of the large pumping plant available, this course was not considered necessary. The feeders of water encountered below this level were dealt with quite easily by the plant provided, and nothing of any interest occurred in either shaft until the coal measures were entered at a depth of 257 yds. from the surface. The top 50 yds. of each shaft down to water level are lined with ordinary cement concrete 18 in. thick, made from sea sand and gravel obtained from the adjacent foreshore and passed through a con- crete mixer in the proportion of six of aggregate to one of cement. The sides of the shaft were shuttered with a specially designed steel casing, and the concrete rammed behind in layers each of about 1 ft. thick. The shaft below the tubbing is lined with cement concrete blocks of the above mixture, 20 to the ring, each block measuring 34 by 24 ft. by 5 in., made to suit the radius of the shaft, and rammed solid with ordinary concrete between the shaft sides and the lining. Sinking Costs. Table II. records the cost per lineal yard in depth of lining the top portion of each 22 ft. diameter finished pit with ordinary cement concrete not less than tfia. G.’-Sectiob through Centre-line OP Fi<5. 3. F1Q. 8.-Plam of Lay-out of Power-house 18 in. thick :—• Table II. Cost of Lining Top Portion of Shafts, per Lineal Yd. Cost per Details. lineal yard. £ s. d. Labour in loading sand and gravel ....... 1 18 6 Enginemen and attending mixer ......... 0 4 1 Cement................................... 3 13 6 Interest and depreciation on shuttering, &c. 0 19 0 Coal, stores, &c........................... 0 10 6 Labour in shafts ......................... 3 1 7 ________ Table IV. shows the actual cost per yard (surface and underground), exclusive of interest or depreciation of capital or of general office charges, for sinking and tub- bing 19 yds. of the South shaft of a finished diameter of 22 ft. :— Table IV. Cost per Yard of Sinking and Tubbing 19 Yards of the South Shaft. Total cost per lineal yard......... 10 7 2 Suitable bricks for the work would have cost from 35s. per 1,000 delivered, and at this price brickwork in cement would have cost from £25 to £30 per lineal yard in depth. There was no material difference in the total cost of lining with concrete blocks and ordinary cement concrete, as the cost of making the blocks was neutralised by the absence of any allowance for interest and depreciation on steel shuttering, etc. The average cost per lineal yard in depth for sinking and walling with 18 in. cement concrete in dry ground amounted to £26 Is. 8d. inclusive. Table III. contains the details of tubbing in the South shaft :— Labour. Contractor :— £ s. d. Sinking .................... 694 10 2 .................... .................... Pumping .................. 247 12 4 Tubbing..................... 339 8 9 Changing buckets and clacks ... 58 15 3 Surface :— Tubbing................... 25 9 4 Enginemen ................. 156 16 0 .................. Firemen ....................... 49 6 8 Mechanics ................. 182 10 3 General labour ............. 92 16 9 ________ Table III.— -Details OF South Shaft Tubbing. Crib Depth from Length of Thickness of Weight of No. surface. tubbing. tubbing. section. Yds. ft. in. Yds. ft. in. In. Tns. cwt, . qr. 1 ... 77 0 10 ... 24 0 8 ... 14 and If .. . 253 7 0 2 ... 99 1 0 ... 22 0 2 ... If „ u .. . 241 5 0 3 ... 118 0 11 ... 18 2 11 ... li „ If .. .. 214 13 3 4 ... 142 0 10 ... 23 2 11 - If „ If If .. 275 9 0 5 ... 152 0 7 ... 9 2 9 . . 120 3 2 6 ... 164 2 7 ... 12 2 0 . ... If and If .. . 165 11 0 7 ... 174 1 9 ... 9 2 2 If . 123 1 1 8 ... 195 1 0 ... 20 2 3 ’ ... If and 2 . 254 11 0 9 ... 215 0 10 ... 19 2 10 . • • 2 ,, 2f .. . 261 6 2 10 ... 234 0 11 ... 19 0 1 ... 2f „ 24 .. . 260 6 1 11 ... 253 0 3 ... 18 .2 4 . ... 24 „ 2f .. . 252 16 1 12 ... 256 2 7 ... 3 2 4 . 2f . 61 19 3 Total length ...203 2 5 . .. Total weight 2,484 10 1 Total .............. 1,847 5 6 Materials. Tubbing .................... 1,186 9 6 ......................... Wedges and sheeting ......... 43 7 5 Timber and cement........... 21 19 8 Coal.......................... 347 6 6 Stores (oil, waste, grease) ..... 55 16 2 Total cost........... 3,502 4 9 ................ Cost per yard ................. 184 6 6 A fair estimate of the cost of sinking and tubbing a 22 ft. diameter shaft through lime- stone, with feeders of water averaging 3,000 gallons per minute, would therefore be about £200 per yard of depth. The actual cost of all labour and materials for sinking both shafts was £107,952; the cost of pumping engines, pumps, and other material in connection there- with, as well as the cost of installing and running the same during the time occupied in sinking, amounted to £66,969; and the total cost of the whole undertaking, when finished, for a production of 750,000 tons of coal per annum, will not exceed £360,000. Both shafts have been fitted with wooden guides and single-deck cages containing six tubs on a fiat. The South shaft is intended for working the Five- quarter seam at a depth of 300 yds. from the surface, and the North shaft for working the Hutton and Low Main seams. The hanging-on level will be at a depth of 400 yds. from the surface. The South shaft was commenced on October 18, 1909, and finished on April 22, 1913, the time occupied being three years and six months. The depth of the shaft is 396 yds., and the length of the tubbing 205 yds. The North shaft was commenced on January 25, 1910, and finished on October 29, 1913, the time occupied being three years and nine months. The depth of the shaft is 396 yds., and the length of the tubbing 204 yds. Fig. 7 is a plan of the permanent colliery arrangements. The Electrically-Driven Machinery. Current and Plant.—Current for driving the electrical machinery is supplied from the mains of the Cleveland and Durham County Electric Power Company. The Horden and Shotton pits of the Horden Collieries Limited are already supplied from the mains of this company. Exhaust steam turbo-generators are installed at both places, which use the exhaust steam from the winding, fan, and other engines, and run coupled in parallel on the company’s system. Surplus energy from these sets not required at any time by the colliery company is taken and paid for by the power company, and colliery peak loads beyond the capacity of the turbo-sets are supplied from the power company’s mains. These two collieries are connected together, and also with Blackball Colliery, by an overhead line. When the permanent equipment of the colliery was first under consideration, it was intended to instal two ordinary steam winders, each fitted with two 30 in. dia- meter cylinders, by 6 ft. stroke, and 16 ft. plain cylin- drical drums, with balance rope. Steam fans and compressors were also projected, and it was intended to