THE MANGAHAO ENTERPRISE.

Shannon News, 7 December 1923, Page 3

THE MANGAHAO ENTERPRISE.

CRITICAL STAGE PAST. GOOD PROSPECTS OF COMPLETION ON TIME. POWER BOARD’S VISIT. On Wednesday the Horowbenua Electric Power Board, paid an official visit to the scene of the headworks oi the Mangahao .system, and spent the day in a close inspection Of the construction .works in progress. As a result of what they saw the ’members of the Board caffie away with a very favourable impression of the present position of the undertaking, and were able to accept, . on the evidence of thieir own eyes, thie assurance that the critical stage of the. undertaking is past and that it will only be some unforeseen happening that will prevent power and light being available in the middle of 1924,.

The party consisted of the chairman of the Board, Mr G. A. Monk,' Messrs A. Mackay (Hutt County),, C. Kilsby (Otaki Borough)i A. A. (Horowhenua County), D. W. Matheson (Levin Borough), W. H. Gunning (Shannon Borough), A. Ross (Foxton Borough), W. E. Barber (Manawatu County),, T. R. Overton (Board Engin-

eer), P. W. Goldsmith (secretary), and representatives of the Levin “Ghroni- , cle” and “Manawiatu Herald.” The weather was very unfavourable, misty rain setting in as soon as Levin was left and continuing) throughout the day. . The ranges behind Shannon were hidden behind a moisture-laden viedl making it ‘impossible to see very far ahead and robbing the outing of its interest from, a scenic point of view, and more important still, 'mak«. ' ing work in the open impossible so

that the party had to'be content with viewing the works without seeing the " operations in progress. Good time was made to Mangahao and the valley reached after the 900-foot descent down the zig-zag path that leads to the river level had been negotiated. Here . the visitors were personally conducted to the points of interest by Mr Johnston, Tile Engineer who has been in ' charger at Mangahao almost since the initiation Of the work. A visit Was first paid to the tunnel that will take the water through to the Arapeti Valley and next the sources of metal for the big, dam were inspected. At first the bed of the Mangahao was exploited for metal, >a') tram line being run up the right bank. Itv was found, however, that these supplies were soon cleaned up and that the fre-,

4uent floods covered the shingle > banks. A rocky outcrop on the other side of the river was therefore drawn upon. ( The -stone is of good quality and is expected to improve as the face is removed- It is taken by a tramline to the crusher and thence to the. dam site. / THE GREAT. DAM. i The main work here is, of course, the huge wall that is to impound the waters of the Mangahao. Great, diffi\culties have been encountered In the initial stages of this work. First and foremost was the problem q.f finding secure foundations on the further sideof the river. Long and tedious boring was necessary as ia preliminary and then the removal of vast quantities of spoil followed!. Then the frequent and rapidly-rising floods destroyed the work of months in as many minutes. Now, however, the river has- -been, diverted through a by-pass tunnel On the . left bank, leaving the old bed clear for thie. concrete Work. On. the further side the main.-wall has been built to-a great height, with, two wing walls al- , most at right angles to the dam to retain the spoil from the -hill side. In the centre the main foundations have been put in, to just above the average water level, -and on the left bank, the main Wall is already taking definite shape. The work has been

greatly facilitated by the absence of floods in November, a condition, unprecedented in the history of the operations. During this spell pf favourable weather the concrete construction 'has been, pushed forward with feverish haste, three shifts working the clock round by the aid, when daylight fails', of powerful electric lights. Only a succession of heavy floods can now prevent ,the completion of this Vital link in thiei scheme and there is

every reason to expect that during ' the next three weeks Nature will ,be kind to the undertaking. Practically, at the present moment the river has been conquered, but, with a know- , ledge, of the caprices of the mountain Climate the. engineers , are not prodigal of promises. Close on 200 men are now engaged at Mangahao and! after Christmas, with the closing down* of . public works in other parts of the (Dominion, the force will he brought up to 240 men. By that time it will f be possible to disregard the menace of the river and ,its flood waters, and so far as the Mangahao portion of the work is concerned the*re will be no need for apprehension. On Wednesday, only the. metal crusher was in operation, but on fine days three shifts each, are worked at the quarry, / the crusher, the tunnel and the dam.

AT THE COOKHOUSE. Before leaving Mangahao, the party had dinner .at thel cook-house, at the ■. conclusion of which Mr Monk took the opportunity of thanking Mr Johns- . ton for his courtesy in showing the party round. He remarked that, amongst the Dominion’s public works, the Mangahao enterprise was the cynosure of all eyes, i To a layman it, seemed as though the engineers and , men had now conquered -the. river, and that the expectation of power next year would be .realised. He paid ■a tribute to the work of the engineers and men and the spirit that sdemed to animate them and' finally expressed the hope that their efforts would be rewarded with full success. Mr Johnston briefly acknowledged the chairman's remarks. To .sum up', it is quite safe to say , that • the river is already beaten at ’ Mangahao.- The only thing that can upset calculations is an exceptional, visitation that, is net reason- ,,:... ably;* to:'beVexpected at the - present. sjage.-is .past and BBMlm

with a good run between now and Christinas the prospect for completion on time is. a rosy -one. The, workers there have had an uphill fight- On lour different occasions they saw the work -of months swept away and destroyed by-‘floods in a lew minutes, but they have carried on steadfastly in -the face of all disappointments. IN THE ARAPETI VALLEY. , The party then returned to the Arapeti Valley, now in mist and rain. The dam here is well under -way. The river passes through a sluice in the middle, but /good progress is being madia and there is not the flood menace to be feared, though the difficulty of securing firm foundations has had to be grappled with. - Before leaving Arapeti a visit was paid to the mile-long tunnel that will bring the water through the hill from Mangahao into the Tokomaxu stream and thence to the Arapeti Valley storage basin. The concreting of the Arapeti end was completed and the wo k was being pushed forward. When the great undertaking was commenced it wa s believed that the tunnels would be the deciding factor in regard to the period of the work. In the issue, however, .the tunnels will be easily*-'completed before the time limit, and it has proved to be, the dams that are the unknown equation. . THE POWER HOUSE.

The other main point of interest was the power-house on the Shannon side; Here the party met Mr Anderson, the Engineer in charge, and were conducted from the crypt-like basement toi the roof 75 feet above. This building is constructed of reinforced 1 concrete of which 5000 'cubic yiards were utilised, 3000 yards being below the main floor level. Beneath the main, floor is a series of concrete chambers where will be housed the turbines that a.nei linked up with the four- enormous pipe-lines that come down the face of the cliff from the surge chamber 900 feet above. The first floor will accommodate the generating!, chambers and high tension rooms. Above that is the switch gallery and then the. low tension floor. The roof, also in reinforced concrete, was being laid down on Wednesday, and it was instructive to see the. method used. It was gathered that the#’power house ' was well in hand, though the pipe line, which is being undertaken on contract, was not so' far forward as. might be wished, but it was not anticipated that the operation of the whole scheme would be delayed on this account. The inspection of the Power House completed the visit, the only portion !'Of the work, that was not seen being the surge chamber at the top of the cliff at Mangaore. The party, some of whom) had not seen, the works for two years, left the scene with conflicting feelings of wonderment at the vast scale on which the undertaking was conceived, and of admiration for the sturdy battle that has been fought for mastery over the forces of Nature. Victory is now in 'sight and when achieved in the course of the next few months it will have reared an enduring monument to the and steadfastness with which the engineers and manual workers have attached what is probably the greatest problem in the history of public; works in the Dominion.