Mexborough & Swinton Times – Saturday 27 December 1913
Huge Colliery Concerns
Graphic Description Of The Denaby and Cadeby Enterprises
Denaby and Cadeby Engineering Developments
A Huge Concern
History Of The Mine
The well-known collieries comprised within the scope of operations of the Denaby and Cadeby Main Collieries (Ltd.) are situated about a mile apart in the valley of the Don, nearly midway between Rotherham and Doncaster, the combined royalty area covering some 10,000 acres in the parishes of Sprotboro’, Conisboro’, Melton, and Denaby. Both pits are carried down to the Barnsley Thick Coal, which is met with at the Denaby Main at a depth of 446 yards, and at the Cadeby Main at 763 yards. The only seam worked up to the present is this famous Barnsley Bed, which out of a total thickness of 10ft. 1in. contains no less than 9ft. 4in. of workable coal, varying in character from soft house and gas qualities to excellent hard steam coal.
Only a small percentage of the vast quantity (approximately 1,000,000 tons) of coal raised from these two famous pits goes into use in this country, the greater bulk being shipped to Hull for overseas consumption and for bunkering purposes.
For the purposes of transport the company have built and now own an up-to-date fleet of steamers ranging from 2,200 tons to 5,200 tons deadweight. All these vessels have been built to the very highest specification and with all modern improvements for labour-saving and rapid discharge. Each steamer is fitted with electric light throughout, and the necessary provision made for wireless installation.
Most of the coal from the Denaby and Cadeby pits is now shipped all over the world, France, Spain, Italy, and the Baltic taking large quantities, which are increasing year by year. A considerable trade is also done with the South American ports. In former years the company exported a very fair tonnage to Hamburg—a business which is now extinct. The loss of the German trade dates from the imposition in 1901 of the 1s. per ton export duty on coal. The incidence of this tax resulted in some unexpected developments, which were doubtless the cause of its repeal a few years later. Not only did Hamburg and other ports in Germany cease to buy Yorkshire coal, but for the first time in the history of commerce Sweden began to take German coal. The trade thus lost has not been recovered, and fresh markets have had to be sought elsewhere.
Channel And Foreign Bunkering
The demand for Denaby and Cadeby Main Washed Steam Coal for bunkers has grown at such a pace that at the request of some of the principal British owners, this company established, a few years ago, a bunkering Depot in the English Channel, situated at Brixham in Torbay. They have two Depot Ships—the “London City,” situated behind a breakwater, which, when finished, will be over 2,000 feet in length, and the “Persia,” just outside the breakwater—both steamers fitted with Temperley Transporters and high-speed transporter engines. It is the largest and best-equipped coaling depot on the English coast. Steamers are bunkered day or night, Sundays or holidays, and as Brixham is perfectly accessible at all times, steamers of any size can berth alongside these Depot Ships immediately on arrival, whatever the state of the tide or weather. There is always a stock of 50,000 tons available.
The support accorded by owners generally to the Denaby Company has been such as to lead them to establish other Depots, and in this respect it may be mentioned that they have now Depots at Port Said, where steamers are supplied with their well-known Bunker coal, and from the 1st of January, 1914, their Depots will be extended to St. Vincent, Las Palmas, and Teneriffe, where stocks of their Washed Steam Coal will always be available.
Modern Coal-Mining
Denaby Main is the older colliery, having been opened in 1864, whereas the Cadeby Main dates only from 1888.
As the younger of the two enterprises, the Cadeby Pit naturally represents the later and more modern developments of engineering practice as applied in mining. Indeed, at Cadeby are to be seen absolutely the most modern methods of coal winning, hauling, winding, screening, washing, ventilation, and delivery on to the trucks. So well is this recognised among experts that when foreign mining engineers make a request to our Government for opportunities to study the English coal-mining methods they are very usually furnished with an introduction from the Home Office to the Managers of the Cadeby Main, requesting permission for inspection of the mine and its general equipment, a courtesy which is always freely extended.
A short description of the installation and banking arrangements at Cadeby may therefore be of interest to the technical reader. As stated above, the only seam worked is the Barnsley Bed, which here has a thickness of approximately 10ft. The shafts are sunk upon the dip side of a large fault, having a throw to the South of 126 yards, and a pair of headings driven through the fault strike the Barnsley Bed on the North side. The depth in the coal is 763 yards on the South side of the fault. No. 1 (Downcast) shaft is at this level, and the shaft is fitted up for a depth of 3,000 tons per day of 15 hours’ winding. Both shafts have a diameter of 16ft. The seam is, in each case, worked longwall, the gates being forty yards apart.
Underground Equipment
On the main haulage roads the coal is conveyed by endless ropes, driven by electric motor (3-phase 500 volts).
There are four pulleys on the main shaft, and the ropes can be put in and out of gear independently by means of friction clutches actuated by hydraulic rams. Subsidiary ropes are worked by friction drums driven off the main endless ropes.
No. 1 pit bottom is filled up with hydraulic chairs for full and empty corves, and the changing is done by hydraulic rams in the same manner as at top.
Winding
The winding engines are similar at both shafts, and have two cylinders 45in. diameter, 7ft. stroke, Cornish Drop Valves, and are fitted with Leggish’s automatic cut-off. The drums are partly fuseed, rising from 18ft. diameter to 33ft., with 12 coils of rope on the parallel portion. The ropes are 6in. in circumference and weigh seven tons. Ormerod’s Safety Hook is used and is connected to the cage by three single links and buffer springs. The cages are four decked, each deck holding two corves of a capacity of 10cwt. each, and are fitted with Automatic Safety Gates. The time occupied in winding is 50 to 55 seconds, and in changing 5 seconds.
All four decks are changed simultaneously by means of hydraulic rams. The guides in the shaft are steel rails, and the clippers cover the whole length of the cages. At the No. 2 Upcast the whole of the pit top is covered in, and is out of sight of the Winder, who is provided with a patent indicator in the Engine House showing the exact position of the cages in the shaft. This apparatus is also fitted with gear to prevent over-winding.
Headgears
These are constructed of lattice steel girders. The height of No. 1 Headgear is 90ft., while that of No. 2 pit is 105ft. high. The pulley wheels in each case are 16ft. in diameter.
Banking Arrangements
The Heapstead is built of steel girders, supported on iron columns, and the coal waggons gravitate underneath the screens. There are three pairs of Chambers patent screens for the hard and soft coals respectively, delivering on to picking belts. The full corves from the shaft pass over the weigh machine and are then raised by a creeper, driven by electric motor, to a sufficient height to enable them to run by gravity to the tipplers. These are also driven by electric motors. After being emptied, the corves are being raised by creepers to enable them to gravitate to the pit.
A special stop block is employed to only allow two tubs at a time to pass on to the hydraulic cage, the tubs behind being automatically held back whenever two tubs are released to load the cage.
All the screens are fitted with a covering hood, and the floating dust is carried away by means of an exhaust fan and delivered to a “Cyclone,” in which it is deposited.
At No. 2 pit top airlocks are provided to enable the workmen and also full and empty corves to pass in and out of the enclosed chamber without loss of air.
Boilers
There are 24 Lancashire boilers 30ft. long, and 7ft. 6in. and 8ft. diameter, 16 with a working pressure of 80lbs. and 8 of 120lb.
Electric Installation
Two Parsons and one British Thomson-Houston Turbo-Generators and two Musgrave Engines and Generators supply electric current for the motors on the pit hill, workshops, and washeries, and also for the underground haulage, and for the pumping station, the total capacity being 2,400 h.p. There is also a De Laval Turbine and Generator of 800 h.p., which can be used in addition. The current is three phase, 500 volts.
The current for the lighting both for underground and surface, including the Colliery Offices, six houses, and Managing Director’s House, is supplied by two 125-h.p. horizontal engines and three continuous current generators, two of 250 amperes at 110 volts and one of 150 amperes at 250 volts.
Ventilation
The fan is 21ft. diameter, Schiele type, and is driven by a single-cylinder engine 42in. diameter and 54in. stroke. The engine runs at 52 strokes and the fan makes 115 revolutions per minute. The water gauge in the fan drift is 2½in., and the quantity of air circulated in the mine is 200,000 cubic feet per minute. An auxiliary Sirocco Fan 9ft. diameter, driven by a 300-h.p. Electric Motor, is provided in case of a stoppage of the main fan.
Pumping Station
Water for the boilers is drawn from the river and pumped into a reservoir 200ft. above the level of the river by means of tandem centrifugal pumps driven by a 50-h.p. motor. The villages of Conisboro’ and Denaby Main are supplied from two boreholes with water which is pumped up into reservoirs on North Cliff, 240ft. above the river by a 90-h.p. motor driving similar pumps.
Duplicate motors and pumps are provided in each case.
Condensing Plant
The exhaust steam from the winding engines passes to an air-and-water surface condenser, where it is condensed. Warm air from the condenser is distributed over the pit hill and washeries for the purpose of warming them, and keeping the hydraulic pipes at the pit top free from frost during cold weather.
The water for the condenser is supplied by 120-h.p. Gwynnes centrifugal pump, capable of supplying 120,000 galls. per hour. After passing through the condenser the surplus water is conducted back to the river, actuating in its course a 40-h.p. water turbine, which is utilised to drive a circular saw and a prop tapering machine in the timber-yard.
Coal Washers
There are three washing plants, the Lührig, Humboldt, and Baum, with capacities of 900, 1,500, and 1,875 tons per day respectively. All are driven by electric motors.
Workshops
There are extensive fitting and blacksmiths’ shops, joiners’ and tub-repairing shop, and foundry. In the fitting shops the lathes for screw cutting, turning, and surfacing, planing machines, drilling, shearing, and punching machines, are all driven by electric power. A girder crane traverses the smiths’ and fitting shops, capable of lifting 20 tons, having a self-acting traverse in each direction, and driven by one 10-h.p. and one 5-h.p. motor. Another 5-h.p. motor drives the blast fan, which is an enclosed Waddle, at 2,300 revolutions per minute. There are also machines for bending rails and girders, and a circular saw for cutting cold iron or steel. Portable compressed air tools are largely used for drilling and other purposes for repairs about the pit hill.
Sidings And Stacking Ground
The sidings are very extensive and are so laid out that all the empty waggons gravitate towards the screens, and when filled, the full waggons pass on by gravity to the full sidings, where they are made up into trains to be taken away by six locomotives.
The stacking ground is situated at a lower level than the sidings, and the full waggons are pushed up a slight incline and tipped up by a travelling crane. Filling up is done by a steam navvy.
Labour
The number of men employed by the company amounts to about 5,000. To provide for their housing accommodation the company has erected or acquired a total of 1,753 houses located in the Denaby Main Village. A very efficient Co-operative Society run by the miners owns also some 66 houses in the village. Though rates of pay have been increased until a nominal eight hours’ day now yields an average wage 11s. 4d., and although the general conditions of work both under and above ground have been materially improved until it is difficult to see in what direction they can be bettered, the account books of the Denaby and Cadeby Main Collieries (Ltd.) show that when wages were at the lowest the men took home more money than they do now, whilst their efficiency was greater.
Whereas 25 years ago the same number of men working together as a gang, under the same conditions as they do now—these were always eight-hours-a-day pits—were able to send to the surface 240 tons of coal per gang each week, to-day their average output is 113 tons. Formerly the men worked for five hours per day, at an average wage of 9s. 2d. per day. Now they work for 3½ days per week at an average rate of pay of 11s. 4d. per diem. In this district it therefore cannot be asserted that shorter hours and higher pay are accompanied by any increase in efficiency.
—“London Times,” December 1.