THE DUN MOUNTAIN RAILWAY.

Lyttelton Times, Volume XVII, Issue 968, 19 February 1862, Page 3

THE DUN MOUNTAIN RAILWAY.

[PUOM TtliK ' NISLBON EXAMINIJII/ FEB. 11.]

The masterly way in which the Dim Mountain Kail way htis been completed makes every detail concerning*1 it a matter of interost,: and we trust, that no apology is needed for devoting more space to tho subject. In laying out tho line, in the first instance, regard was had to two main points: the position of the ores already got, and the facility of prolonging the road with workable gradients to the main bulk of the Mining Company's property. The estate of the Dun Mountain Company, with the land held by them on mining lease, forms a range of mountain crests, including an amphitheatre or basin about a mile in diameter. In the bottom of this basin is a source of one branch of the Wairoa river, which runs through*: the Wainiea valley into Blind Bay. The highest peak of the Dun Mountain lies to the north-western side of; this basin. The chrome bed known as Duppa's reef, and most of the workings for copper hitherto made, lie about the sides of a peak to the Westward of the main summit, and divided from it by a dip which forms the pass from the head of the Wairoa river already named to the head of the Maitai stream. The "railway enters the Dun Mountain Company's property on the south side of this westerly peak, and, in order to carry the line round to this side of the mountain on which lies the valley of Maitai, this dip or saddle must be crossed. No lower level wonld answer this purpose, and no higher woitlfj answer to reach the main peak of' the mountain and the eastern and southern sides of the basin of the Wairoa head; This saddle or pass became then the ruling or summit level of the line. Two other important points intervened between the summit and the spot in Brook street chosen for the dep6t, viz.,- a low point on the ridge which divides the Wairoa from the Brook street valley, and another on the ridge which connects the Dun Mountain with the Fringe hill. Pour points were thus fixed which must determine the character of the gradients; heavy cutting or embankment being out of the question with the limited funds at the disposal of the Engineer. The want of funds also prevented any elaborate survey of the ground before beginning operations. The Engineer was obliged to content himself with finding the level of the four points thus described by means of the aneroid barometer (an instrument of the utmost value in a country so rugged and obstructed as this) and with a general estimate of the distances that the line must extend along from one point to another. Having done this with all care, and calculated the gradients necessary to unite these levels, he proceeded to mark out the line by the surveyor's common spirit level, on a uniform ascent, beginning from the level of the depot in Brook-street, and fixing each distance peg one uniform height above the preceding one, until he reached the second of the four points named, the ridge between the Brook-street valley and the Wairoa, known to those who have explored the hills as the Wairoa saddle. Notwithstanding the simplicity and apparent inadequacy of the data on 'which this operation was founded, and the. tediousness, difficulty, and labour of planting an instrument probably from 500 to 1,0.00 times, and making twice as many observations on ground where it is a hard matter to stand, and much of it encumbered with forest, the gradient thus set out reached within twenty feet .(in a height of above 2,000 feet and a distance of eight and a-half miles) of the desired point, and by returning and modifying the ascent for a comparatively short distance, this part of the preliminary work was done. The two other gradients being shorter, the difficulty and uncertainty were proportionately less. And the whole was finished in two months, although in this, as in other parts'of the work, the inconvenience of having no experienced assistants must have greatly added to the labour. The above details of the setting-out of this line illustrate the saying that no human art is a mystery: plainer sailing than this it would be difficult to imagine. But the result shows also that there are things about human work higher than mystery in its vulgar acceptation. We are not venting common newspaper flattery in saying that the Dun Mountain Railway is a triumph of conscientious perseverance.

The line, after passing- through the shales, and clay.slate well known to the inhabitants of Nelson, comes upon a broad band of limestone, dark grey, veined with crystalline white. This rock seems almost at right angles to its original stratified position; its bed being nearly vertical. Then, again; comes more slate and we arrive at the mineral beds. It would be very dull to our readers, were we able to give the names of half the curiosities of geology here to be seen. The appearance of the place is singular. You emerge from the black birch forest on to interior, of the basin already described. It is scattered very thickly with rocks, stones, and sand, and very sparingly with vegetable mould or vegetation. The general aspect is suggestive of a metallic character. What may be the exact colour properly called dun is debatable; the Dun Mountain, however, is of a sort of gun metal hue, and certainly looks as if it ought to have abundance of copper. Scanty scrub of manuka, birch, and rata covers some ridges, and has extended farther; blackened branches everywhere show the work of former miners and explorers, and add to the dreariness. In dull weather the place may well bo described as " the abomination of desolation."

The first sign of activity you arrive at is a small openingl mado in ft supposed lode of copper twenty or thirty feet below the line, from which the ore described in ft former paper was brought;. The magnetic ore does not, however, seem to constitute the bulk of the load so for as it lias been openod. It is what Cornish miners call grey ore, of n dullish metallic grey colour, interspersed with malachite, and other blue salts of copper, with occasional specks of native metal. The lode had been previously observed at this very spot, and a small heading was commenced close beside where the miners are at present working, but so as to miss the ore by a few

inches.. At present the lode shows every sign |of continuity. It has been exposed lor about I twenty feet,and maintains a thickness .of I fifteen inches. It lies nearly vertically, the dip being- to the westwards. It is intended ;to send a ton of the prodjiee to the smelting I works at Sydney by the next mail. | ; A little further up, and about twenty feet | above the line on tho left hand, is the first 1 working- of chrome ore, and half a mile further on tho same side, but rather higher j above the railway is the main working1. The I chrome reef lies tolerably level on its out- | crop, dipping inwards ; and there is no reason to doubt thnt it may be worked at little | expense for many years. In fact the whole of the minerals of these mountains may be got at for some time to come by open quarrying-, or at least by headings and drifts without any considerable shafts, or lifting and pumping machinery. Now that a means of transport to the place of shipment has ; been constructed, the great elevation and abrupt slopes of the mountain will be in all other respects advantageous. In oa-der to arrive at the former workings known as the Old Mine or wind-trap gully, you cross over the saddle to that side of the hills next the Maitai; and as a large part of these lodes lie below the saddle, even should they prove, after all to be profitable, they will not be opened until after all the minerals above the railway, and a large part of those in the basin of the Wairoa head, have been operated upon. The practicability of obtaining a supply of lime by the railway, depends on the question whether the black birch has sufficient heating power to serve as fuel for the lime-kiln. This will be tested before long. In the meantime many tons of firewood, last winter's cutting, are stacked on the sides of the railway, and the company will realize a sum sufficient to keep the line in repair by the sale of this necessary at a material reduction of the rates at present ruling in Nelson. The railway to the Dun Mountain, the first completed railway in New Zealand, and from which so much material good is expected to arise to the Province of Nelson, was publicly opened on Monday, Feb. 3. Eight trucks, laden with chrome ore, and accompanied by several of our townspeople and a band of music, left the Company's depot in Brook-street, at about twelve o'clock, and proceeded, amid the cheers of the numerous persons by whom the several streets were thronged, to the port. After the chrome had been deposited on the wharf the trucks again returned to town, and, at about three o'clock, the local directors, and some friends, the engineer of the line, and the workmen employed in the construction of the line, amounting to about 180 persons, sat down to a cold luncheon, which had been provided in Mr Everett's usual style, at the Freemasons's Hall.