The Westport-Stockton Coal Mine.

Progress, Volume IV, Issue 2, 1 December 1908, Page 44

The Westport-Stockton Coal Mine.

The Westport-Stockton Coal Co.'s Mine, which was opened on October 6th, 1908, is easily the most interesting coal mining proposition south of the Equator, and, in view of the extent of the coal deposits, and the high calorific value of the coal, one of the most interesting in the world. A general description of the plant will be interesting, as illustrating the combinations of rope haulage and electric haulage used. The coal deposits lie at a height of from 2,500 ft. to 3,000 ft. above sea level, and the converse of the usual practice had to be met in this case, namely, bringing the coal down instead of raising it, as in the majority of coal mines. The general scheme that has been adopted is the use of two main inclines with steel rope haulage, by which the trucks are handled, the loaded cars going c!oa\ n pulling the empties up, the rope speed being controlled by a powerful hydraulic brake on each incline. From the head of the top incline to the mine the electric locomotives handle the trucks both ways, the small "gathering" locomotives making up the loaded trains by gathering loaded tubs from the various working faces in the mine proper, and breaking up the empty trains, distributing the empty tubs to the faces. Power House. — The Power House is of ferro-eoncrete construction, and is fireproof throughout. It is 174 ft. long by 50ft. wide, and is divided into three compartments — engine room, condenser room, and boiler room. There are two main generating units, each consisting of a British ThomsonHouston 3-phase Generator, 375 kw. 6600 volts, 60 cycle, direct connected to and on common bedplate with a 475 b.h.p. Bellis and Morcos triple expansion engine, the set running at 400 r.p.m. The engines exhaust into a Worthington Surface Condenser : capacity of condenser, 26.0001b5. of steam per hour with circulating water at 55deg. F. A Worthington Centrifugal Pump draws circulating water from a well near the Power House. The three-throw Edwardes type air pump is engine driven by an engine of 25 b.h.p. condensing. A Webster feed water heater is installed capable of raising 26,0001b5. of water per hour 30deg. F., using exhaust steam from the two boiler feed pumps and the engine driving the automatic stokers. There are four Babcock and Wilcox boilers, each capable of evaporating B,ooolbs of steam per hour, from and at 212deg heating surface of each boiler, 619 square feet. They are fitted with super-heaters capable of superheating 150deg. The boilers have automatic stokers and chain grates with 4-speed gear feed, the stokers being driven by a small 15 b.h.p. simple engine.

The boiler feed pumps are Tangye manufacture. There are two of these, each capable of supplying the boilers with 75,0001b5. of water per hour against a pressure of loOlbs. steam. It will be noted that the auxiliaries are of sufficient capacity to take care of the ultimate engine and boiler capacity of the plant, which will be double that at present installed. There are two exciter sets, each consisting of a British Thomson-Houston 14 kw. 88volt generator, direct connected to and on common bedplate with Bellis and Morcos simple engine condensing, the set running at 600 r.p.m. For lighting about the plant, and for operating a number of d.c. motors used on the elevators and tipplers in '•he main eeal storage bins, a motor-genprator set is installed in the power house. This set consists of 100 kw. d.c. 280-volt flat compound Generator direct connected to a 8.T.T1. 3-phase 6300 volt form K. 150 h p. motor, the set running at 705 r.p.m. The main switchboard consists of eight panels of white marble and three blank panels to provide for future extensions. From left to right, the switchboard is made up as follows : — Feeder panel for generator of motorgenerator set. Generator panel of motor-generator set. Starting panel for motor of motor-gen-erator set. Two blank panels. Two main generator panels. Main high tension feeder panel. Blank panel Two exciter panels. The d.c voltmeter for the motor-genera-tor set is mounted on extreme left panel, the synchronising indicator and exciter voltmeter, together with Tirrill regulator, oeing mounted on extreme right panel. Hoists. — There are two small auxiliary panels near the main board, one for the control of a 40 k.w. 6600 volt primary 230 volt secondary transformer, this +ransformer supplying current for the operation of a 52 b.h.p motor connected to Lidgerwood hoist. This hoist is located near the bins, and is used to pull the Government Railway coal trucks out of a dip on to an incline, from which they are distributed by gravity into the various tracks under the bins for loading. After loading, the trucks also run by gravity to the main siding, where they are made up for despatch to Westport. The second auxiliary panel is for the control of a 75 k.w. 6600 V01t primary 230 volt secondary transformer, this transformer supplying current for a 112 b h p. motor connected to Lidgerwood hoist This hoist has two drums Avith main and tail ropes, and corresponding brake and friction clutch levers. The one drum is used for hauling loaded coal tubs from the foot of No. 1 incline through the Ngakwau

tunnel to the bins, the other for drawing empties from the bins through the tunnel. An auxiliary arrangement is also provided so tnal tubs and miscellaneous material can be hauled up from the shops and stores to the tunnel level. Right-of-way.— The Ngakawau tunnel is 28 chains long, and has an average grade of lin 60, in favour of the load. The tunnel commences about 100 yards from the bins, and runs through to the foot of No 1 main incline. This main incline has a grade of 1 in 3.25 for 17 chains, and a further grade of 1 in 4.25 for 16 chains, in favour of the load. On this incline the tubs are handled on a steel rope l%in. diameter, the loaded tubs pulling up the empties, the whole movement being controlled by a powerful hydraulic brake located at the top of the incline. At the head of No. 1 incline No. 2 incline starts. This starts with a grade of 1 in 5 for 21 chains, and a further 1 in 19 for 17 chains, in favour of the load. The tubs are handled on this incline with a l^in. diameter steel rope, this being controlled from an hydraulic brake, located at the top of No. 2 incline, the method of operation being identical with that on No. 1 incline. Jacket water for the cylinders of both the hydraulic brakes is supplied under natural pressure. Electric Locomotives. — At the head of No. 2 incline the trucks run on to a level plat where the main electric locomotives begin their run. These main locomotives deliver the loaded tubs from the mine to the head of No. 2 incline, and pull back the empty tubs. At present the company have three of these main locomotives and two "gathering" locomotives. The main locomotives weigh 20 tons each, and are equipped with Sprague-General electric type M. control, to enable them to be worked as separate units, or coupled, as desired. Their draw-bar pull is 75001b5., with a speed of 8.2 milps per hour. In order to guard against any possible chance of a locomotive taking down a loaded train of trucks getting away on the steeper grades, a third rail is located in the middle of the track, projecting a few inches above the level of the two outside rails, a very powerful toggle brake on the locomotive engages both sides of the head of this centre rail, giving tremendous brakeing power. This type of brake is known as the Fell brake, and has been applied by the engineers of the General Electric Company to these 20-ton locomotives. The smaller, "gathering" locomotives, are of the G.E. standard IM.-101 type, weighing 6% tons each, with a draw-bar pull of 25001b5.. and a speed of 7.4 miles per hour. The d.c. trolley potential throughout is 250 volt. As before stated, these small "gathering" locomotives are for pulling full tubs to be made up in trains for the big locomotives to handle, and for breaking

up the trains of empties and distributing the empty tubs to the working faces. The coal tubs weigh 15001bs. each empty, and when loaded 45001b5. ; in other words, each loaded tub carries 30 cwt. of coal.

The gathering locomotives are equipped with a reel automatically worked from the locomotive axle, containing 900 ft. of flexible twin cable, to enable the locomotive to have an operating range of this distance beyond

the farthest point of overhead construction. Track. — The track from the head of the top incline right into the mine is of extremely solid construction for this type of work, having 561b. rails on substantial

sleeper construction. The raiLs are 40ft long, and at each joint are bonded with two Xo. 00 bonds, being cross-bonded every three rails. The gauge is 36 inches. From the head of the top incline, where

the main locomotives hand over the loaded trains, to No. 1 sub-station, is 35 chains, grades varying from 1 in 132 to 1 in 12, an average of 1 in 25, all in favour of the load, with a minimum curve of 2 chains.

From No. 1 sub-station to No. 2 sub-sta-tion, at the mouth of "A" tunnel, is 145 chains, grades varying from 1 in 12 to level, average grade being 1 m 21, with a minimum curve of 2 chains, all in favour.

From No. 2 sub-station to No. 3 sub-sta-tion, through "A" and "B" tunnels, is 79 chains, "A" tunnel being 15 chains long and "B" tunnel 64 chains long, grades varying from 1 in 10 to level, average 1 in 17, in favour of the load, minimum curve 5 chains radius. "A" tunnel has been run purely for construction purposes, but coal will be won in all the other tunnels. As the mine is developed, track will be continued through "C" and "D" tunnels, extending 110 chains beyond No. 3 substation, and excellent coal has been proved for two miles beyond this point. The track is single at present, and is provided with necessary turnouts to handle the traffic. In the whole layout, however, provision has been made for double tracking throughout. Overhead Construction. — With regard to the overhead construction. This is also of a most substantial character. The trolley used is General Electric Co. 's grooved No. 0000 throughout, and in parallel with it for the whole run is a bare stranded cable of 600,000 cm. The feeder cable is tied to the trolley on an average every 150 ft. The trolley wire is 7ft. Bin. from the level of the head of rails. Sub-stations. — Three sub-stations feed the overhead trolley network. These are identical with regard to electrical equipment. In each sub-station is a motor-gener-ator composed of a d.c. 280 volt flat compound 200k. w. generator direct connected to and on common bedplate with a 3-phase 6300 volt form K. 300 b.h.p. motor, the set having three bearings. The switchboard consists of three panels of white marble. From left to right, — Starting panel for motor with automatic oil switch. D.C. generator panel. D.C. feeder panel with voltmeter on swinging bracket. Transmission Line. — The three sub-sta-tions operate in parallel, and are served

with 3-phase current at 6600 volts, the transmission wires throughout being No. 0 hard drawn bare copper: total length of transmission line, six miles. A lightning arrester ground wire of five No. 16 stranded galvanised wire is run throughout thy high tension line, stapled to the top of each pole, and is effectivelygrounded on an average every fourth pole, the distance between poles averaging 150 ft. There are nine transpositions in the transmission line. Telephones. — Telephone lines connect the three sub-stations, power house, offices, etc., on metallic return, and are run on the transmission line poles from the power house to the beginning of the tramway track, and from that point to the end of the

line follow the overhead construction. Each locomotive carries a portable telephone, by means of which a train can at once communicate with any of the points on the telephone network. Ventilation. — With regard to ventilation. The mine is exceptionally fortunate in this respect, in that but small fan capacity is n 'quired to assist and maintain the natural ventilation. Two fans, each driven by a 30 h p. B.T.H. 3-phase 500 volt motor, are used, one being located in the centre of " B " tunnel and the second in the centre of "C" tunnel. These motors are belted to centrifugal fans. The object in using 500 volt 3-phase motors for driving the fans is that this service will be con-

tmuous, irrespective of any possible interruptions to the trolley overhead network. In addition to the above there are six Sturtevant blowers, each belted to a 5 h.p. d.c. 250 volt motor, which will be located as required at different parts of the workings, the motors taking current from the overhead trolley. Drainage. — The natural drainage is so excellent that the only provision made is a small Worthington pump, direct geared to a 5 h.p. 250 volt d.c. motor, this outfit being portable and readily moved to any point in the mine where it is necessary to pump out any small dips that will occur in working. Coal-cutting. — For the winning of the coal, machines will be principally employed. The company are starting with two Sullivan board and pillar chain machines with 6ft. cutting bar, each machine driven by a 30 h.p. G.E. motor. These machines are the first of their class to be used in New Zealand. The Company have already proved 30,000,000 tons of coal in sight, the coal averaging about 14,000 British thermal units, being practically as good as the very best Welch coals mined. The seams vary from 6ft. to 12ft. in depth in the workings already opened, and the coal is entirely free from slate and bands. With regard to the actual workings, the mine is extremely fortunate in having a solid sandstone roof, which will necessitate the use of very little timber for its support, this fact necessarily greatly increasing the rapid winning of the coal, with a corresponding decreased cost of production. Storage Bin. — The main bin into which the coal is finally delivered has a capacity of 5,000 tons. It is divided into three compartments, two of 2000 tons each for the storage of unscreened coal, and one of 1000 tons capacity for the storage of screened coal. The loaded tubs run into the bin by gravity, being thrown into any one of the tipples desired, when they then turn over and discharge the coal on to the travelling elevators, which in turn deliver it to the various bin compartments. The tipples work

automatically, the loaded tub in turning over carrying up an empty tub, which is then run down on the siding ready to be made up in a train for its trip back to the mine. The main bin is composed entirely of ironbark built on pile foundation. Its loading capacity, if required, is 35 trucks at a time. The loading doors work in a horizontal plane, and are opened and closed by hydraulic rams operated at a pressure of 2201b5. per square inch, the pressure being obtained from a small stream near the top of the main incline. The three elevators are operated respectively by two 10 h.p. and one 15 h.p. General Electric Co. C.q. motors, and the shakers are operated by three 5 h.p. Co. motors. After coal is delivered from the bin into the trucks of the Government Railway, these trucks, averaging about 9 tons each, are pulled 22 miles to tidewater at Westport, on the West Coast of the Southern Island of New Zealand, this port at present admitting steamers to a draught of 22ft., although the Government (under the authority of an Act passed last session), have just authorised the expenditure of £200,000 to facilitate coal handling and enable steamers of 30ft. draught to enter the port. Other large coal deposits in the neighbourhood are being taken up, and will doubtless be in full operation in the near future, making Westport one of the largest coal handling ports in the world. Although the mine is on the coast, no harbour accommodation is available nearer than Westport, which at present is able to handle 1,250,000 tons of coal per annum. The engineer of the company, Mr Broome, has proved himself a remarkably able man by the very complete and excellent layout he has made of the whole mine. The complete contract for the electrical apparatus has been carried out by the Australian General Electric Co.. and all the electrical apparatus is either General Electric Co., U.S. A .or British Thomson-Hous-

ton Co.'s manufacture. The contractors have been ably represented by Mr. J. Schmidt, acting in the capacity of their constructing engineer. The figures in centre picture, page 45, are: — From right: Messrs. Recce, Browne (mine manager), and Barlow (electric engineer), driving. The General Electric Co., U.S.A., and the British Thomson-Houston Co., of Rugby, are represented in Australia by The Australian General Electric Co. The NewZealand representatives are the National Electrical and Engineering Co., Ltd., a purely New Zealand company, having headquarters at Dunedin. and branches in Wellington and Auckland.