AT MANGAHAO
POWER WORKS INSPECTED
PROGRESS OF THE SCHEME
WHAT MEMBERS OF PARLIA- | MENT SAW Tho power works at Mangahao. which were visited yesterday by members of Parliament from the Wellington district, have been described often, nnd most Wellington people have probably a general idea of what is being done. Yet a visit to the ground is bound to evoke surprise, The scheme is bigger than it looks on paper. The work already in: hand extends over some ten miles of country, and penetrates at the inner end into virgin bush, where great totaras and ratas have to be felled to make way for the working gangs. The Mangahao Stream, which is to be harnessed in the service of Wellington Province, is running freo at present down a valley that is completely clothed with dense bush, with the raw cut of a road as tho sole evidence of man's intrusion. From the ridge the stream, rippling over grey boulders, appears a mere creek. It represents some 20,000 horse-power because its waters can be dropped 900 feet to tho Pelton wheels. The visitor to the power works leaves the railway at Shannon, and takes the road at right-angles to the lines towards the hills. The power-house site is two or three miles away, at the foot of the first range. A tunnel about a mile long is to penetrate these hills to the vnlley of the Tokomaru and Arapiti streams. In this valley will be tho first reservoir, really a lake formed by damming the stream at a narrow gorge iust below a wide flat. This flat, eight miles from Shannon, is at present tho site of a growing settlement created by the Public Works Department and destined a few years hence to disappear boncath the waters. Beyond the next rid»c, which is also to be tunnelled, is the" Mangahao Valley, containing the stream that is to furnish the greater part of the water for the power station. A 90ft. dam in the Mangahao Valley is to create a second reservoir, feeding the Tokomaru reservoir through tho tunnel. $. third reservoir, which will serve also to hold back moving sand and shingle, is to be formed about a mile and a half further up the Mangahao Stream. Statistics about the Teservoirs and the tunnels do not convey much information to the layman. The salient feature of the scheme is the diversion" of water from the two valleys, set high in the hills, to the power-houso on the Shannon flat where the steel pipe lines will deliver it with a "head" sufficient to drive a group of Pelton wheels coupled to dynamos capable of producing 24,000 hoTse-power.
Work on the Power-house. Leaving Shannon in motor-cars shortly after 11 a.m., the Parliamentary party camo quickly to the site of tho power-house. A few men are employed thero preparing for the erection of a steam plant, which is to generate elect™ current for the driving of air compressors and other plant (hiring the boring ot the first tunnel and the construction of the Tokomaru dam. ,The Mangahao tunnel and dams are to have another powor plant. Two.boilers and some other gear are already on the powerhouse site. Much remains to be done, but access is easy, and this part of the work will bo ready by the time it is required. The' old Tokomaru Itoad runs past the site and over the range to the Tokomaru Valley. It is a steep and narrow road of a common bush type, with some difficult hairpin bends,- and although tho Public Works Department has done mucb to' improve it by widening and metalling, it still provides awkward travelling. The motor-cars required assistance from their passengers once or twico yesterday. But the-engineers say t)hat the road will carry all the loads' that will have to bo placed upon it ns the work proceeds. Tents amid the bush, on tho hillside show where some roadmen are housed. Running down into tho valley after crossing the ridge, the party had a bird'seve view of the site of the first reservoir. The valley widens at the junction of Hhe Tokomaru and Arapiti streams, and then contracts to a narrow gorge. A sawmill once stood in the broad of the valley, and its site is shown by the remains of tramlines and a great mound of sawdust. The timber used to go over ths ijidgv? towards Shannon on a cable tramline, long ago dismantled. Tho men employed at this part of the works have been living in tents, under conditions of discomfort, but huts are now being built with timber cut in a small'sawmill up the hill. A dozen tats, each providing accommodation for eight- men, 'have been authorised, and several of them' are nearing completion.. Later a. dining hall, a recreation room, and some o,tlior necessary buildings are to be provided. The coqkhouw at present in use is primitive, but the T.M.C.A. has come to the assistance of the Department, and 'has a capable representative and a. comfortable mar-, quee in the valley. Excavation for the Dam.
At tho neck of the valley excavation is proceeding for tlie dam. A took expoouru is/required, by the engineers, and tile excavation has not gone far enough to niako Vie exact position of the dam certain. A narrow roadway running up the uili near the dam site leads to tne point where the, boring of the Mangahao tunnel is to begin. A tramline is to be laid on this roadway to bring down the tunnel spoil. Some of tihis 'spoil is to bo used in the preparation of the concrete for tho dam, since sound rock is hard to obtain in the neighbourhood. The other tunnel, running back towards Shannon, is to be called the Arapiti tunnel, if will enter the hill at a point furthci up the valley than the Mangahao tunnel, and, of course, on the opposite side. No boring l has been done at either tunnel yet. Tho disposal of spoil from the tunnels and the dam' is ono of the difficulties that the engineers have had to'' faco. It is being overcome by the diversion of the stream at a horse-shoo bend a lew 'hundred icet below the diun. The engineers, by cutting a new channel across the horse-shoe, are making room for 10,000 or 11,000 cubic yards of spoil at tho bend without obstructing tne stream or reducing the storage capacity of tho reservoir. On a bluff overlooking the dam site foundations are being prepared for a stone-crushing and concretemixing plant. From tho site of the first reservoir, tho Public Works Department has made a new rood across the hills to the MnngAhao Valley. The road does not descend into tho Tokoma.ru Valley at all. It stays up the hillside and skirts what will bo the 6hore of the lake that is going to be brought into existence. Quickly this road enters virgin forest, where some day the eawmillers will work. Big trees tower above it, and tlje tangled undergrowth of the bush fringes it. Bond metal of useful quality has been hard to find here, tho engineers having to rely largely on pockets of rathor poor stuff exposed during tho work, and the motorcars could not complete the journey to the ridge. The party proceeded on foot, in mud that occasionally was anklehigh, and presently reached a point overlooking the Mangahao Stream. The sides of this valley aro particularly «tecp. Tho road has proceeded to n point about 700 feet nbovo the stream. The engineers have decided to go downwards from that point by means of a cable tramway at a slope of 40 degrees, and the necessary clearing has already boon done. Looking down this clearing, the party could see where tho dam was to bo built and where tho tunnel would begin. The Mangahao Stream looked disappointingly small, but tho.party was assured that the volume of water was greater than it appeared. No member volunteered to go down and investigate. A. powor-houso site is being prepared close to where the inclined tramway will reach the Mangahao Stream. A steam plnnt, using wood as fuel, is to bo Installed there to drive the air compressors and provide nny other power required for the Mangahao tunnel and dam. It would have to make the one power plant serve both tunnels, but tho enginoers considor that iho use of two vmiis is the more con-
venient .arrangement, with tho special advantage that a temporary breakdown at any point will not stop all the work. The second Mangahao dam will not bo begun until the first is completed. Then the plant nnd materials will be rafted up tho artificial lake as far as possible towards the site of tho second dam. The delivery of current from the powerhouse need not await the preparation of this second reservoir. The cable tram down into the Mangahao Valley i? to uso wooden rails and will have two cars connected by the cable. When _heavy loads have to bo sent down, the car that is coming up will be weighted with stones or log 3 so as to keep the TJalance. These.details.nnd many others tho en. gineers have arranged.
Work on Contract System. The number of men employed on tlio Mnngahao works at the present time is 121. Work could be found for more men, but the policy of tho engineers now is to provide reasonably good accommodation before putting men on the job. Huts and cookhouses are being erected. Tents still in use are being provided wooden floors, iron fireplaces nnd""other improvements. Communications are being improved and clearings extended. One result of these efforts is that men who had previously loft the works owing to the bad: conditions aro coming back. The outer camp, near the ridge above the Mangahao Stream, has been greatly improved in recent weeks, and tho men can now cnt and sleep in some measure of comfort. They havo tho bad months of the year immediately ahead of them, but the conditions are stnted to bo improving all the time, and by next spring the Department should be in a position to increase the labour force substantinllv 'without creating a hens' ing difficulty. The working conditions havo been improved, from the point of view of the men, in another tcspeets. The engineers have been arranging that as much a? possible of the work shall be done under tho contract system. Some men, about one-sixth of the total number employed, are still on daily wages and are receiving the Departmental rate of 13s. Gdl a day. But the rest are working on contracts, and the party was informed yesterday that these men aro averaging something like 18s. a day. They appear satisfied and the work'is now proceeding smoothly. Much of the "Spade Work" Completed. The members of Parliament naturally were anxious to learn when the installation would bo completed and the power made available for use. Tiieyfdid not got any exact information on the point. Tlio engineers, speaking with professional caution, thought that the power might be turned .on in three years, or four years, or five years. They pointed out that fortune had not always favoured them in tho past. Tho shortage of decent road metal, for example,' has been a serious matter and has inTolvcd increased labour and Joss of time. Materials of all kinds have been difficult to obtain, and much will depend upon whether or not this trouble continues. Timber is still in short supply, although it is being cut on the spot from an abundant sunply of logs. The sawmill is turning out not much more than 2000 feet a day, and it is held up in wet weather because the sawbench has not yet been roofed. The reason given for the delav in the erection of a roof was that the timber was required as fast as it was cut.for other essential work. This reason did not look good to tho party, but it would not be fair to emphasise a point of this kind in disregard of the very largo amount of work that has actually been done right from the power-house site to Mangahoo stream. The engineers appeared to tho party to ho justifiod in claiming, as they do, that they havo already completed much of tho tedious a.vl disappointing spade work and aro in a position now to proceed with tho operations that will show Quick results. The tunnelling is expected to bo completed in eighteen months from the time of starting, but that time is not fixed. The visit to the work's was arranged by the Central Progress League. The party that made the trip included Messrs. G. Mitchell, M.P., J. P. Luke, M.P, R. A. Wright, ALP.. J. A. Nash, M.P., H. Hunter, M.P., W. H. Field, M.P., B. W. Smith, M.P., A. 1> M'Nicol. M.P., >A. .D. M'Leod, M.P., and B. H. Crabb (Palmerston North). Mr. P. W. I'urkert, of the Public Works Department, accompanied tho party, which was shown over the works by Mr. A. Dinnie, tho engineer in charge, and members of his staff. Lunch was provided in tho Y.M.C.A. marquee on tho site of the first reservoir, and tho members of the party expressed their very warm appreciation of the hospitality extended to them and of the efforts of (•voTybody concerned to facilitate tueir inquiries.
Allocation of the Power. | The Mayor of Wellington (Mr. J. P. Luke. M.P.) stated Inst night that he had been glad of the opportunity to inspect the works at Mnngahao. The shortcomings that had existed in tho matter of accommodation for the men employed at tho works seemed to have been remedied to a largo extent. Provision was being made for an increased number of workers. Tho amount of completed work, apart from road formation, was not large, but ho did not doubt that from an engineer's point of view much progress had been made. It was encouraging to hear that men who had previously left the works were now returning, showing that the conditions had been made more attractive. The public, added Mr. Luke, was fairly familiar with the scheme. The important question for "Wellington people was when the power would be available. "The engineers," he said, "are very confident that the 'current will be available within a period of four years. In fact, one engineer' expressed the opinion that it would be available in three years. Wo have to be cautious about accepting estimate* but the Government; certainly should bo urged to make possible endeavour to complete the work at the earliest possible moment. Tho power is wanted now, and it is going to be wanted increasingly as industrial and domestic requirements expand. A .question that interests Wellington particularly is the allocation of the- power when it is available. I believe that tho Public Works Department has realised the need for speed. I cannot see why tho Department, knowing that there will be a maximum 0f.25,000 horse-power available, should not determine the proportions that will be available for tho different districts. If the City Council could nsccrtain how much power it may expect from Mangahno, it would know its position, and would be able .to estimate what other plant was required. It is absolutely necessary that the information should be made availablo at the 'earliest possible, moment."
Improvements made Recently. "Considerable improvement has been effected sinco my last visit to the works." said Mr. G. Mitchell, organiser of tho Central Progress League, last nieht. "I am glad to be able to say Hint. There is an amount of vitality and organised effort that was not apparent earlier. Better iccommodation has been provided for the men, and this important part of tlio work is still proceeding. The cook-houses hove been so arranged as to give reasonable promise of comfortable meals. The roads are better and are still being improved. I attach very great importance to all this, since we cannot oxpect speedy and satisfactory work unless the tien employed on the job are housed decently tnd saved from unnecessary hnrdship. "A good deal of work has been done lately on the actual scheme. The necossary'roatling has been nearly completed. Tho power-house sites and the dam sites are boing prepared. I think the progress that is being mado, considering til tho difficulties, may bo vegurded as )"'rly -satisfactory. Still I liopo that the work is going to be pushed oil in No fiituro at even greater speed. Continuous vigorous effort is required, and I fol' tliat tEo Progress League and 'h people of Wellington generally must .i i rolux their efforts to encourago and stimulate the Public Works Department Jo increased activity. Good accommodation will be available soon for a larger number of men than the Department is now employing, and it is cbvious that the work is there fot the. men. "T-h» date of completion is not a question on which! visitors can form a defmito opinion. The engineers believe that the tunnels, which have not yet been commenced, can be driven in eighteen months/but some time must elapse after that before current becomes Evailablo. J hflpo that tho Minister of Public Works wiU bo ablo to say something deimite
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Dominion, Volume 13, Issue 206, 26 May 1920, Page 8
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2,870AT MANGAHAO Dominion, Volume 13, Issue 206, 26 May 1920, Page 8
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