BOROUGH LOAN PROPOSALS.

Gisborne Times, Volume XXVII, Issue 2653, 8 November 1909, Page 5

BOROUGH LOAN PROPOSALS.

THE ENGINEERING ASPECT.

MR. MAROHANT’S REPORT

The following report was received on Saturday by the Town Clerk, from Sir. F. W. Marchant, C.E., on the engineering aspects of the borough loan proposals: INTRODUCTORY. “At a special meeting of the Gisborne B'orough Council I answered questions in reply to Councillors who sought information concerning them. The report now made repeats or amends them to. some extent, and gives more matured opinions than I.was able at first to express STREET METALLING. “I inspected the Ivaitaratahi gravel pit and Gentle Annie quarry, and subsequently in Wellington had a lengthy conference with Mr. Jarrett concerning the report he made on the subject to you. "■ “My opinion is that you should use the river-bed gravel in all cases as a foundation for the hard limestone metal, and that where there is but light traflic and the limestone metal was not absolutely required that the streets should be covered with the river-bed gravel only. “I propose to haul the limestone metal by traction . engine and hopper waggons. I deal fully with all the points involved in the foregoing propositions. KAITARATAHI GRAVEL.

“I think the system you have instigated for the excavation and haulage of this by rail to town is a good one, and do not suggest any alteration in it. “The tracks in the river bed should be led to the best and roughest deposits of gravel. At present the best deposits are not being worked, and there is an excessive amount of dirt and grit in it. “All-grit and pea gravel below £in diameter should be screened out, and the rougher gravel used for the streets.' The small stuff passing through the screen should he used for footpaths. “My opinion is that the screening should he done at the Council’s gravel depot in town. It is not impossible to perform the operation at the river bed, but it would be expensive, and a great hindrance to working operations. With Mr. Lysnar I called on the General Manager of Railways in Wellington, and discussed the class of railway waggon which the Department could or would supply for the haulage of this gravel. Eventually the' General Manager agreed to alter the flooi's of the waggons by putting a tran-door in each so that the waggon could be run over a hole at the town depot, the trap-door opened, and the waggons quickly emptied with very little hand labor. ’ I should have preferred proper hopper waggons, but as they could not be supplied, the best substitute had to be agreed to. After the waggons have been thus emptied, the gravel would be elevated and screened by machinery, and stored in overhead bins for quick and cheap loading into the road waggons. “My opinion is that the total cost of getting, hauling, emptying, screening, and storing should not exceed 2s 9d per cubic yard. Of each yard thus screened, I think that, say, /0 per cent-, would be of value for the streets, and the balance for the footpaths or for blinding the metal if an insufficient amount of chips were yielded in process of crushing tne limestone. “To load the road waggons from.the storage bins, haul to different parts of the town, spread and roll same would cost under 'is 3d per cubic yard, _ so that I should put the cost of the river bed gravel at a finished cost of 4s per cubic yard. The cost of power and elevating machinery, storage bins, etc., may be put at £IOOO, having a saleable value of £4OO when the work was completed. LIMESTONE METAL FROM GENTLE ANNIE. “The quarry site, the class of metal, and the manner in which it can be worked are uniquely favorable. The stone requires no blasting, and yet is of high-class quality. The whole operation of getting, crushing, and storing can be performed by gravity. “I advise the use of a Hadfield’s steel crusher, with manganese steel jaws. I find these very reliable machines, turning out a first-class, clean, broken metal. “The installation of chutes, steam plant crusher, bins, etc. would cost about £I2OO, saleable for £SOO on completion. The cost of getting, breaking, and storing should not exceed is Oif’per cubic yard, delivered in the bins at Gentle Annie. HAULAGE OF METAL TO GISBORNE. “I have give a great deal of consideration to this problem, and have discussed the subject with men engaged in the mechanical haulage of goods in Canterbury in competition with the railway. , “My opinion is that the haulage or metal from Gentle Annie to the streets of Gisborne should be by means of a traction engine pulling a train of waggons. Substituting wool and grain for road metal, Canterbury has many parallels but less favorable examples of this mode of transportation. I dismiss the tramway project, as I hold that the cost of its construction is out of all reason in comparison with tho amount of material to be carried, and, secondly, if traction engine carriage can and does compete with a public railway earning all it can with passenger and general traffic, then it is quite impossible that the tramway project could give economical results. “It would be necessary first of all to make a small piece of road diversion at Gentle Annie and to culvert and fill some hollows on the road. Those improvements made at a cost of, say, £SOO, the whole of the road would then be downhill to Gisborne. I propose to use a 10 nominal Ir.-p. compound traction' engine mounted on springs and . preferably of McLaren or Fowler s make, as these seem to be most favored by men engaged in this calling. Such an engine should have specially broad tyres, together with extra and special wheels for street rolling. It would easilv haul a train of waggons containing 15 cubic yards and- make nine trips a week. I believe that with « capable and energetic, driver very much better results would be ob- “ Tho waggons would have- 9-inch tyres, the front wheels ,set at a narrower gauge than the others so that the load was .distributed over as great a width of road as possible. Ihey would be of lioipper pattern, with doors arranged to that the contents could be properly spread on the streets. Si-k such waggons should be built for use and stand-by. The total cost of the haulage plant would be about £IJUU, and when done with would be saleable for about £IOOO. . , “The working cost of such a plant would be £l3 a week at the outside. Repairs would cost about £3 a week. “The cost per cubic yard then would he 135 cubic yards a week hauled at a cost of £l6, say 2s 5d per cubic yard. Spreading and rolling on the stflsets

would cost, say, Is per cubic yard. This makes the total cost of the limestone metal 2s 9d, plus 2s sd, plus Is — 6s 2d per cubic yard lor working expenses. To this must be added depreciation of- plant, £6OO for crushing machinery, etc., £9OO for the haulage gear, and £SOO for alteration of road, also maintenance of same. Interest on cost of machinery has also to be allowed for. It would, I imagine, be necessary for the borough to maintain the highway ip good order, or else contract with the County Council for the work.

“It is not possible to state the cost in any other way than I have done, as I do nob know to what extent theBorough Council may use this metal, nor over how long a term the work may continue. I think, however, it may be safely .stated that allowing for all working charges, of whatever nature, the cost of the metal would fie about 8s 6d a cubic yard, and this is 2s 6d a cubic yard more than the price of it in Tirnaru, where the Milestone has to he quarried by blasting and hauled by traction engines about two miles over steep gradients. “There is, I am aware, a great difference of opinion in Gisborne concerning this question of haulage of metal. It may therefore be interesting to quote actual examples or the cost of transport by this method. “A haulage contractor in Canterbury competes with a branch railway 40 miles in length. The road has many ups and downs, the inland terminus is situated about 1000 feet above sea level. He gets about 15s a ton for 40 miles. Compared with the Gisborne road he could nob travel ,at much more than half the speed that is possible in Gisborne, on account of the steepness of the road in places, open riverbeds, etc., to he traversed. He finds all plant, pays all wages, stores and repairs, has to load and unload by hand, and make his profit besides. “An English example taken fropi actual experience also gives the cost of traction engine haulage at under 2d per ton per mile, allowing 5 per cent, interest per annum on plant, and 15 per cent for depreciation and renewal of plant. Thsi example is for a full load hauled 17 miles one way only, returning empty. “In thi.s example three men were employed, whereas in the Dominion never more than two are used on each engine. Allowing for the difference of circumstances, I should estimate the cost of haulage at 4d per cubic yard per mile for all expenses. Judged by this estimate the cost of haulage, 13 miles, would be 4,s 4d, plus 2s 9d at quarry, plus Is, spreading and rolling. This makes it 8s Id per cubic yard on the streets. “I do not believe in cutting these estimates. All sorts of contingencies arise, and have to be provided for, and probably the Council would be wise in reckoning on 8s 6d per cubic yard for the work, adding to it the interest and depreciation of the plant which must be obtained. FORMATION OF STREETS.

“Having ascertained as nearly as possible the cost o-f the street material at, say. 4s for the river gravel and Ss 6d’ for the limestone metal, the apportionment of these on the streets must be considered. On the main thoroughfares exposed to heavy traffic I suggest a 4-inch layer of river gravel rolled in and covered with from 5 to 8 inches thickness of broken stone metal, the thickness dependent upon the amount of traflic using it. This would make a far better and much cheaper work than using a Telford pavement of Maihirere stone for the bottoming, as the metal could be worn down to the last film still having the river gravel below. If streets are to be metalled out oi borrowed money, it seems to me that they should he made so substantially as to endure for the currency of the loan period, and this cannot be attained unless a generous thickness is provided in tho first instance. SUMMARY OF STREET WORK REPORT.

“In carrying out work of the character considered the organisation of the plant is of the first importance, Gisborne has practically speaking a clean slate in'this respect, and I advise that nothing but the best and most complete arrangements should be made. Generally speaking the smaller municipalities get through their work with a small capital expenditure on plant and arrangements, but expend a considerable total amount in simui sums at different times, and see very little return for it comparatively.

TARRING OF STREET SURFACES. “I advocate this very strongly. It is antiseptic, prevents dust, the streets dry quickly after rain, and it greatly decreases the wear of the metal, so much so, that if the streets are periodically top-dressed and tarred, their life is prolonged indefinitely. “There are several patterns oi pneumatic tar spraying machines now on the market, and one of the best or these should certainly be used instead of the former method of hand applica“The Council should provide special tar storage, or else contract with the gasworks for it, as otherwise the quantity required might not be available when needed. . , - ' - “The cost of a spraying machine is under £l5O. ELECTRIC LIGHTING FOR THE BOROUGH. “If the electric light is installed so that I could tap the mains for energy to drive the pumps in connection \utn the server age scheme, then the cost or the latter could be reduced by at least £2OOO. x . “This would be only a small -part of tlie saving, as if the electric light was installed the electrician staff otherwise necessary for the sewerage scheme would be dispensed with. Instead then of a. skilled and unskilled staff being required for the sewerage work at a large annual cost, we should only wati a sewerman at a wage of under £loo a of the electric light in Gisborne is an •excellent project. “There are, however, details about the proposals made with which I am in agreement. _ “I place no value at all on the uso of the borough water supply as JJ. .generator of. energy. It would have done well for the sewerage scheme alone as I proposed, and which only required quite a small power to drive it, but as a means of providing power tor lighting tho town, or as an auxiliary to it, I think it practically valueless. It is proposed to use suction gas ongines for the lighting. If so the greatest care must be taken to prevent any flicker in the light, lhe agreement between tho Borough and the contractors should strictly specify that the photometric power of the light does not vary at all. Gas engines used for this purpose invariably (m my experience) cause the lights to jump more or less at each impulse of the engine iimess the current is passed through a storage battery. 'This flicker is ruinous to eyesight. “I much prefer a steam engine as a prime mover for electric generators. The light is absolutely steady, as it should be, there is always a large reserve of power in the boiler for any sudden demand, and these sudden de-

mands are very .frequent (as the meters on the switchboard indicate) and steam' is always to be depended upon. Tho point in favor of suction gas is that it is'l the cheapest prime mover in existence jj excepting natural water power underll favorable conditions. But in the ease of a town’s electrical supply for light- j ing and power, I do not think it wouitl|| be found to be anything like so satis- j factory as a high-class steam engine. j “In small installations such as J ' proposed for tho sewerage scheme, a storage battery was a necessity. In, the case, however, of a public electrical supply. I think a battery would prove j very expensive to instal and maintain, i “Recently in connection with a large ; public institution in tho Dominion where a storage battery was used for the 1 night supply after say 10 p.m., it has been found cheaper to discard the bat- - tory, and employ a night staff t. maintain. the power. “In ‘the event of the Council deciding on an electrical installation, and with which I fully agree, I think the j points I have raised concerning its details should be submitted tor the opinion of some highly experienced expert engaged in this particular class of work in one of the larger centres. In any case whatever,j>rime mover may be employed, it should bo installed in duplicate to guard against temporary breakdown. , PROPOSED PASSENGER TRAMWAY. “I think that for the special circumstances of Gisborne the proposal to -use self-propelled cars Is a good one, 'instead of attempting to use . n overhead electrical system deriving its power from a central station as is done in larger centres. “The construction of the permanent way is a very important ,bem. It should consist of heavy anti deep rails laid on a firstclass road bod. If anything cheap is attempted, the track will soon become ricketty, wearing out itself ; and the travelling plant, besides rendering tho travelling uupk asant. “This question of a passenger tramway was not brought before me at all, except incidentally, but 1 thought l had better express my opinion about it from an engineering point of view. RESERVOIR. “At present the'water supply to tho town depends on the integrity of a main pipe 20 miles in length, giving about 3uo feet effective pressure in tho town. No storage is provided. The question is as'ked by the Council whether in my opinion a reservoir should he provided, and in what position. , “The points involved are as .follows: Without a reservoir any excessive flood or earthquake which might damage tho nes or joints would render the town temporarily waterless. Not only would this he very serious, but if a fire broke out at the same time great damage might he clone in spite of the auxiliary fire-fighting plant the Council possesses. “With the installation of a sewerage system, which is an absolute necessity, great inconvenience would ensue from a failure of the water supply even for a few hours.

“My opinion decidedly is that a reservoir should be constructed, and that nothing under a capacity ot two millions of- gallons would bo of any real value.

“1 inspected plans and searched tho hills about Gisborne very carefully, and at lasi came t-o tbe conclusion that the Kaiti Hill immediately above the- Freezing Works was an ideal spot for the reservoir. The ground is soft sand- ; stone, absolutely safe against slip, and ■ it can be set at the requisite height To j give .the same pressure in the mains 1 as they now have. • 'The reservoir I propose would be circular built, of reinforced concrete, \\ and roofed in with the same. The if roofing is a necessity, in order to pre- j| vent the generation of sun-slime, which 1 in course of decomposition renders the ,5 water “fishy, ” and in order to exclude ;f <1 list and dirt during heavy rains. ’5 An 8 inch pipe wouid be laid to the -j lexer voir from the main opposite Mrs. J Sheen’s house, and also a 10 inch one from the Gladstone Road across the if Turangpnui bridge. “In any great conflagration the reticulation of the town would thus be fed from both ends, giving a vastly better fire service than can now be ! S had. “It would have been desirable to bare made the reservoir of greater capacity than I propose, but the site | is a broken one, and a good deal of excavation will be necessary in order to provide room for the size I propose. “I do not think it necessary to carry | the 10 inch main under the Turanganui River on the chance that some time or other the swing span of the bridge may have to be opened. Inquiry | elicited the statement that this bridge • had not been opened for a great many ■'< years. It would be necessary to provide special sluice valves and expan- ;| siou joints in the pipe line so that if i| necessity .required it might one day be opened.” Even then, while the flow was cut off for opening the bridge, tho town would be supplied as at present, with the S inch pipe from the reservoir in addition. “Complaint was made to me that during heavy floods the water supply of the town” became very dirty. The construction of a reservoir would largely obviate this, as while the reservoir supply held out tho main bringing down dirty water from the intake could he shut off. 1 estimate the cost of a reinforced concrete reservoir complete with excavation, pipe connections. overflow, and fittings, at under £BSOO, for a capacity of two million callous I should prefer that the Council allowed £IO,OOO for the -work, and enlarged the capacity as much as could be done for the greater amount. SUMMARY OF WHOLE REPORT. “Probably there will te many in- l quiries concerning details of estimated, expenditure and explanations required. b*v the Council when these schemes come to be submitted to the_ ratepayers, and estimates are being drawn up. These I cannot now foresee, but have dealt with all the .subjects as fully as seems now to be necessary. It tho Council will formulate any questions.;,; which I have not answered herein, 1 ? shall be glad to reply to them as tully as possible. , r _ , “F. M. MAR OH ANT, 3kL Inst. C.E. § “Timaru, November, 1908.”