ENGINEERS' CONFERENCE.

Otaki Mail, 7 March 1923, Page 3

ENGINEERS' CONFERENCE.

MB DAVIES AT AUCKLAND. Conference was opened by Mr Gunson, Mayor of Auckland, on Monday, February 19, in the Technical Institute, lie referred to the special advantages local authorities would receive by such gatherings. Local Governments, ho said, were more than ever dependent upon the professional man, and Councils reeuguised that if the best must be obtained engineers should be given an opportunity to compare experiences. He was delighted to see such a large attendance and to know that representatives wort ' there from far north to the south of the" South Island. He wished all a pleasant and profitable, stay whilst in Auckland, and assured them of every facility in inspecting the many works of the City Council. Mr Gunson's remarks were heartily applauded, and on completion the President of the Society thanked him for the welcome on behalf of the members. The usual business was then proceeded with, viz., minutes, appointment of officers, balance-sheet, etc. After the ordinary business had been dispensed with, the reading of papers commenced. The following is not a complete list of papers read, but are the most important from the standpoint of County and Borough Councils.

(1) The economical re-location and improvement of existing roads by alteration in grades and alignments. (2) Notes on road location. (o) Street paving by Trinidad asphalt. (-{) Tar-macadam treatment of roads. (5) Bituminus and tar-treated roads. (0) Road culverts. (7) County engineering as relating to roads. (S) Roads in the province of Quebec (9) Sullivan-service reservoir (Dunedin water-supply), (Hi) Los Angelos water-supply undertaking. (11) Water supply (notes ou). (12) Algae in water. (13) Pipe linn secondary stresses. 114) Standardisation. t 15) Xotes on the centralised fuel power-house, complementary to hydroelectric energy. The President V- address was taken first. This dealt with the coal supply of New Zealand. Graphs were given showing the increase in amount won from the mines since 1880 to the present year. This increase amounted to about -5 per cent, every 10 years, such increase agreeing with the previous experience of older countries. Tableswere then given of Hie Government geological surveys of coal fields in New Zealand. From these (after allowing for the assumed rate of increase) the probable life of the coal supply in New' Zealand was deduced, which is estimated at about 60 years. The visitor's next object was to suggest means of conserving this supply. In New Zenland the consumption per head of population was about L'l tons (Great Britain 1} tons) exclusive of bunker-coal for ships. This consumption is analysed as follows: Kail« ay 15 per cent. Coastal Steamers 5 per cent. Factories, Trams, Engineering, Bricks, Cement, etc.3o per cent Domestic 10 per cent. I Less 10 per een t. I The writer went on to explain that v "lib development all classes would ineiea.se, though the -1" per cent.'for do-me-tic purposes could be decreased by the use of hydro-electricity. The total coal (estimated) in New Zealand was as follows: Proved '149,000,000 tons. Estimated (Geological Dept.) 1,407,000,000 tons. By the present method of mining not more than 50 per cent, of coal could be mined owing to the large arches left for supporting the roof. There was also a very large waste through the small coal not being marketable. This had b£en made into briquettes in some countries, and if proceeded with a great saving could be affected. The use of this coal for power generating purposes had also not been fully exhausted. The extent to which hydro-electricity should be installed, along with the use of gas for heating purposes, was fully considered iu the address. The first paper taken (marked 15 ou above list; was really a criticism of the Government in proceeding with the Arapuni hydro-electric works until the demand for this load had grown to such an extent (or was in sight) to.ensure that such a scheme would pay, Mr Brown proposed to instal a steam generating plant at Huntley. Tito writer (Mr Brown; contended that the capital tost could be kept down by installing sufficient power to meet the demand' and increasing units as required. This could be readily done by erecting steam plants iu the heart of the coal fields where fuel was cheap. The advantage of utilising some of the waste coal as indicated iu the President's address would also be met., The paper was supported by several engineers. Mr Birk (chief electrical engineer) gave a very detailed reply, with 'figures to show that the optimism of the Government was justified, and that the Arapuni scheme would pay after the first year. Particulars had been taken of every small hydro plant in the North Island, which would be used as "demand creating units," and in matay eases (as in Wellington and Christchurch) steam and hydro plants would be used as "stand-by units" in the event of temporary failure of the main scheme. Mr Crookes and other engineers of the Auckland Power Board, supported the Government proceedings at once- with the main scheme, and proved that within a few years Auckland city would require up to 30,000 h.p. The total output of Arapuni scheme is 150,000 h.p. The chief items for discussiojl. however, were road-makhjg and preservation of same. All classes were discussed, viz., concrete, macadam, earth, tar-mac-sdam, groutinj, and tar-painting, • the typa to V>6 choaart being a question of

economics, depending upon population, traffic, and grades of roads. Several experiments had been taken shatwing the saving in power effected over a period of 40 miles by tar-1 rented and macadam road, and from this data the cost I>er mile a council would be justified in spending (with a given traffic) was deduced. In a short summary of the con- ' ference this data cannot be given, though papers and discussion thereon j will be printed later, and issued to each I member of the institute.

1 Among the works visited was the Nihipotu dam, which will be the chief water supply for the city of Auckland, situated about 18 miles out of Auckland. It is now almost complete, but - has taken about 7 years to build. Other works visited were the concrete and laying of tar-macadam roads within the city, also a visit to the street works of the Tamaki West Road Board. This Board has recently let a contract for the laying of five miles of roading with Union asphalt to cost £13,750, the width of tar work to be IS feet. The method employed is what is termed the penetration method, and consists of scarifying | the road surface, then laying four inches of metal, rolling it without a binder, and immediately after, spraying tar on to penetrate through the crevices. At this spraying the amount of tar used is equal to 11 gallons per square yard. After further rolling, more tar is supplied and carried over with line chips

of metal, thus making a settled surface. Other important works inspected was the Auckland Electric Works (now in course of erection), and the harbour extension. On Saturday the conference J finished, and was generally considered to have been one of the most successful. On Saturday Mr Da vies travelled on to Uotorua. Sunday was spent in look- j ing around Whakn and Rotorua, where hot springs, geysers, spout baths, quaky ground, and hot mud-pots are evident. Whaka is well-known as a Native town, though the hot springs make it a particularly weird place, especially at night. Rotorua, however, is well-known as n very pleasant town, with its wide streets and beautiful gardens. When leaving Rotorua. on Tuesday morning the party were informed thai the first elections for Mayor and Council would be held that day, the Government having approved of the formation of a Borough to consist of two representatives from the Government and four Councillors to be elected with a Mayor. Taumaraiiui was reached by 7 a.m., where the journey was broken, principally to inspect a stone-crusher offered for sale by that Council. The Chairman of Works' Committee and engineer took Mr Davies over the crushing plant and street works, also the hydroelectric plant, new in course of construction from the Wanguuui river. This borough, with a population of less than 2,500, has recently carried loans totalling £OH.OOO £60,000 for electrical machinery with mains, and £36,000 for street improvement. They have a. bed of shingle similar in mauy respects to Otaki. A stone-crushing plant has been erected complete with screens and bins for collecting various sizes of metal, from sand to 2 J -inch. They have also purchased a steam roller and scarifier along with a steam self-tipping wagon for carting the metal from bins to the streets. The amount spent on the above street-plant amounts to approximately £SOOO. The cost per yard of metal crushed, equals to an average of 3s (id, according to the amount put through per day, but the best effect of such a plant is noticed on the roads. They are able fo place the right size of metal with binding, and later consolidating with roller, using a plentiful supply of water. The crusher for sale can be purchased for £275. It is in good order. This. however, will be more fully dealt with in Mr Davies' report to Council upon proposed street plant. Mr Davies left Taumaranui at 2 a.m. on Thursday (an unearthly hour) arriving at 3.45 with a four hours' stay at Palmerston North. During his absence he had been impressed with the necessity of some advertising medium, whereby the merits of the town could become more generally knewn. Most people recognised that the climate was good, but judge the town from what is seen from the railway station. He believed it would pay this town to set aside a certain sum per annum for advertising purposes.