New Zealand Marble

Progress, Volume XI, Issue 7, 1 March 1916, Page 565

New Zealand Marble

The Beginning of a Great Industry. Visit to the Kairuru Quarry and Tramline.

After ten years of failures and disappointments, New Zealand marble is being produced in ample quantities, and of splendid quality, from the Kairuru quarries, near Sandy Bay. —Description and photographs by Chas. E. Wheeler.

New Zealand marble, of high quality, is just beginning to make its appearance as a building material. It exists in ample quantities, but the deposits are situated in country so difficult of access

ers should be proud—designed in their country and built of splendid materials obtained in the Dominion. Behind the successful shipment last February of a cargo of fine sound marble lies a history of ten

that it was only after the expenditure of £5,000 upon a tramway rising from sea level to the head of a deep ravine 1,130 feet above sea level, and six and a half miles distant, that this valuable stone could be made available for practical purposes.

Rarely does a new material enjoy an introduction of so auspicious a nature as this Kairuru marble, as it is called. The finest national building in New Zealand, the new House of Parliament is being built of it from the first floor, the base being of Coromandel grey granite. Kairuru marble is white, with grey streaks, and its general effect is grey. Thus the two Nbav Zealand stones will harmonize nicely, and the front elevation of the building, with its dome, lofty lonic columns and spacious loggias, will be an architectural sight of which New Zealand-

years of failures. Settlers in the Sandy Bay district, and the mountainous region stretching back from the bay to the main road between Motueka and Takaka have always had faith in “the marble being there”—but the problem has been, not only to get it away, but to find a deposit of stone sufficiently free from faults to warrant the heavy expense of working.

One venture was started on sufficiently substantial lines to give great hopes of success but the hillside quarry which this particular company worked with only fair results is now lying idle, and the rails are pulled up from the incline heading to the bottom of the valley. The marble-seekers have had to go another four miles inland to secure good sound stone, and they have now laid firm the foundations of a great industry.

UNSUCCESSFUL EFFORTS Ten years ago, Mr. John Campbell, Government Architect, endeavoured to bring New Zealand marble into prominence by inducing the Government to order a block for an exhibition in London. A Wellington stone-mason undertook the work, and although cost was not a very important consideration, he failed to produce the block of marble. He undertook to open a face and quarry out a stone, which would be partly polished, but he never attempted the task, probably quailing before the tremendous

Mr. Campbell had no hesitation about including New Zealand marble in the materials specified for Parliament Buildings. The other stones were Mount Somers limestone, Tonga Bay granite, and Coromandel granite.

EXPERTS’ OPINION. A committee of experts was set up by the Government to deal with the important question of the stone to be used in the national building, and they came to the conclusion that marble was preferable.

difficulties involved in getting a heavy weight transported over country which comprises a constant series of steep valleys or ravines, most of them 500 feet deep.

The next step taken officially was in 1911, when Mr. Campbell visited the district and obtained various samples of the marble. Again there was nobody forthcoming to face the difficulties of working the splendid material. Mr. Campbell was then shown the Kairuru deposits which ultimately proved to be the most perfect, though most remote from, the sea. A company was formed to take quarrying in hand on a substantial scale, and with that assured,

Samples of marble from Kairuru were tested, for the committee’s information at Canterbury College by Professor Robert Scott, with the following result:

Crushing strength—76o to 830 tons per cubic foot.

Weight—l9l pounds per cubic foot.

By way of comparison between marble and other building materials it is worth noting that Oamaru stone has a crushing strength of 40 to 90 tons per cubic foot, and Mount Somers limestone 180 tons per cubic foot. New Zealand marble is as strong as most granites.

These tests of resistance under crushing strain are regarded as most important in building materials, where the strain is mostly that of dead-weight. It is estimated by the designer of Parliament Buildings that the heaviest crushing strain will be in the twelve lonic pillars on the front elevation. There the strain will range from 15 to 20 tons per cubic foot, so that Kairuru marble, with its crushing resistance of 760 to 830 tons, provides an enormous margin of safety beyond the usual one required by architects, that of ten times actual strain.

caps of the columns of Parliament Buildings out of four-ton blocks, and they give the marble high professional praise when they say it “cuts to a fine arris. ’ ’

As to the weathering quality of New Zealand marble, this has to be proved. However, the aspect of the stone in situ provides reassuring evidence,, so that there is no reason to believe that the material will disappoint remote generations of posterity who will gaze on their national building. It is well known that certain qualities of Italian mar-

KAIRURU MARBLE DESCRIBED. Kairuru marble is coarse-grained, highly crystalline, and bears a strong resemblance to the marble obtained by the Greeks from the famous quarries of Naxos and Paros islands in the Aegean Sea. Prom this material the glorious buildings of ancient Greece were constructed, and but for the ruthless hand of the spoilator, they would be standing intact to-day. Is it anything more than a coincidence that the vandals of those days were Turks, allies of our modern Huns from Prussia ?

Coarse grain is a quality of value. The finer the grain, the more dead the polished surface. Kairuru marble, with its coarse crystals, gives a beautiful lustrous polish of a creamy depth. The stone works well. Carvers have already commenced to chisel the

ble have stood well in a sulphur-laden atmosphere, in fact the beautiful national memorial to Queen Victoria erected in London, contains 1,000 tons of Italian marble. It was, however, selected with the greatest care, only 25 per cent, of the quantity cut being used in the memorial.

DISAPPOINTING OUTCROPS. Anyone who climbs the endless spurs of the mountains back of Sandy Bay would gain a general impression of boundless supplies of marble, only waiting to be quarried. But the history of Sandy Bay marble has proved that it is difficult to find a patch of the valuable material sufficiently free from shattering to warrant its use in building. I have before me in writing the photograph of one of the

celebrated Sagro quarries of Carrara marble. Onehalf of the picture is taken up with an enormous mass of “faulted” rock. Then it suddenly ends, giving place to a splendid “face” 50 feet square of absolutely unbroken marble which has to be sawn out by wire saws, electrically operated. The view—except for the 50 feet of marble face —is singularly like those to be seen in New Zealand’s marble district. One may see the huge mass of shattered rock in the abandoned quarry of the old Sandy Bay Marble Co. Under ordinary conditions, one expects

side by granite rock. The most plausible line of explanation is that the marble overlaid the granite, and that a subsidence involved most of it in the folds of the granite, shattering it to pieces. One sees remnants of the ancient marble bed scattered in fragments on the hill-tops. Fortunately, there was one mass, extremely narrow, which was not apparently so much involved in the movement. It escaped a great deal of the shattering and crushing to which the remainder of the deposit was subjected. This lays on the western side of the line of a great ravine

to find solid rock beneath this overlay of faults, but the Sandy Bay venture disproved the theory, and those who are interested in developing New Zealand’s marble resources will tell you with a sad shake of the head that sound rock is not to be got by merely digging deep for it. This is why the tramline from the sea penetrates six miles of rugged country before a satisfactory marble deposit is reached.

PROBABLE ORIGIN OF THE DEPOSITS. There is more than one geological theory to account for the presence of an isolated occurrence of marble in a well-defined line, bordered on either

running from Kairuru almost to the sea. On the eastern side of this ravine, along which runs a tramline to the marble deposits, the protective granite wall is plainly visible. Cuttings made by the tramway builders are of fascinating interest to the geologist. There one may come across cliffs of granite, but the rock has decomposed, so that it could be removed by the shovelful like sand. Resting against it one finds the marble, subjected to the same decomposing elements, but hard as steel though shattered by great strains of earth movements. The tramline, running alongside one side of the deposit, might be regarded as an extensive prospecting cut in the hillside, but in spite of the fact that marble

cuttings are numerous, not one of practical commercial value was reached until the tramway came into Messrs Hugonin and Henderson’s property. The owners had long known of a fine outcrop of marble within their boundary but never hoped to develop it when there were miles of marble outcrop between Kairuru and the sea. But the failure of the Sandy Bay venture gave them their opportunity; they brought the Kairuru deposit once more under the Government’s notice, and as it was already favourably known to the Government Architect, the Minister of Public Works agreed to help a languishing venture of tremendous potential value by building the tramline to Kairuru. The cost will eventually be repaid by the company now working the Kairuru deposits. THE KAIRURU QUARRY.

The new tramline is hardly in full working order, but by dint of great care in trucking—and much exertion in replacing derailed loads! —it was possible to make the first shipment of marble to Wellington on February 19th last. The undertaking being thus in working order, the time seemed favourable for a visit, and thanks to the kindly hospitality of Messrs Hugonin and Henderson of the Kairuru station, one important difficulty associated with the trip was happily overcome. The daily motor-car service between Nelson and Takaka serves Kairuru, which is about six miles up the high hill leading out of Riwaka. The Kairuru homestead is scarcely a quarter of a mile from the main road, and the marble quarry only another quarter of a mile, as the crow flies. But this quarter mile gives one a speedy introduction to the character of the country. The hillside drops at a steep angle, sometimes more than 45 degrees, and the quarry though so close to Kairuru, might be three miles away in a practical sense, when the difficulties of the rugged hillside are taken into account. On the way down, we pass the marble outcropping with granite. An illustration of a prominent rock is reproduced on page 568. This is not a true marble, as it has become schistose in structure. It was photographed as a typical outcrop on the edge of the true marble.

GREAT MASSES OF MARBLE. There is no real quarry face at the head of the tramway, but the great mass of splendid marble blocks awaiting trucking shows that at least the uncertainties of supply arc over. In the pile of stone near the crane, illustrated on page 566 are blocks of sound marble, passed by the Government Inspector, totalling 12,000 cubic feet. These have been taken, practically from the surface. The real quarry face to be opened up is behind this pile of stones, a few score yards up a narrow gully, where giant marble rocks, stand up like rugged castles, defying Time itself. They measure out at 200 tons of sound visible marble, and how far they go beneath the surface, quarrying operations must be awaited to prove.

A block measuring 30 feet in length, 30 feet in width and 7 feet in thickness was taken out of the

face at the tramway head. It weighed 520 tons. So enormous a mass was, of course, impossible to move from the quarry. It was cut into fifteen stones averaging 5 feet by 5 feet by 2 feet 6 inches thick, without a fault. Rarely docs a quarrying enterprise start with such remarkable ease. There is usually a great overlay of shattered rock and soil to remove, but in this case the great problem was not how to get sound stone, but how to transport it. And that difficulty has now been overcome.

SOME OF THE STONES. At the stage of quarrying when rubbish has to be cleared, the quarrymen have put out fine square blocks suitable for the caps of the front columns of Parliament Building. Here are the sizes and approximate weights of some of the stones illustrated on page 566-7.

6 feet by 6 feet by 3 feet: weight over 9 tons.

6 feet by 5 feet by 2 feet: weight 5 tons. 6 feet by 3 feet by 2 feet: weight 3 tons.

This stone will be identified in the photographs as the one against which a quarryman’s rule, four feet in length, has been placed.

5 feet by 5 feet by 3 feet; weight 6 tons. 8 feet by 4 feet by 4 feet: weight 10 tons.

15 feet by 2 feet 6 inches by 2 feet 6 inches: weight 7 tons.

At the proposed quarry face, sound stones 15 feet in thickness arc showing over a large area. One rock has been measured up to a length of 25 feet, and another is 45 feet long. The stones lie in stratas, a joint occurring at about 5 feet intervals, so that all the quarrymen have to do is to drive a series of holes along the top of a rock, and split it vertically by means of steel wedges—the operation known as “plugs and feathers.” Explosives will be rarely needed at the Kairuru quarry. The operation of plugging is at present done with long iron bars —jumpers—but a compressed air drilling plant, to be driven by steam, is awaiting erection. The Kairuru Marble Company has also under consideration various types of power crane, with a view to installing one capable of dealing with the heavy lifts required. Ten tons is the present limit of weight which can be transported over the tramline, but the quarry furnishes sound stones greatly exceeding this weight. When transit facilities improve, larger blocks of marble can be delivered, if they are required. The splendid surface rocks available have given the quarry a great start, more stone being ready for trucking than can be taken over the tramline for many months to come. The quarry foreman, Mr. Thomas Cooper, has had lengthy quarrying experience at Mount Somers and Timaru, and more recently as foreman at the greenstone quarry on the West Coast.

EXTENT OF VISIBLE DEPOSITS. The present limit of visible stone goes 200 feet above the face of the new quarry, and it evidently runs into the hill a considerable distance.

The marble can be traced down the valley to a point 300 feet below the face, the intervening dis-

tance being covered with debris. However, it is assumed that with such large masses of sound stone at both ends, it will only be necessary to remove the debris to expose further extensive deposits. This will be a task for future generations, because there is more than sufficient for the present uncovered. The sound rock exposed on the west side of the gully, pictured on page 568 is sufficient to provide all the marble needed for Parliament Building.

It is difficult to define the full range of colour in the Kairuru marble. What has been opened up ranges from dark blue-grey to pure white. A few stones show beautiful tintings of pink, and occasionally there are small blocks obtained of such dark blue colour that they could well be used with the white stone for tiling contrasts, when the effect would be black and white.

difficult to devise an easily worked line. The scheme finally adopted involves a gigantic ziz-zag down one spur, ending in an incline 777 feet long with a grade of 1 in 2.

Starting from the marble deposit, the line which is of 8 feet 6 inch gauge skirts the left, or eastern side of the deep valley, and runs on a slightly risinggrade for the first mile. The descent then commences, the grade limit being 1 in 10. Huge swal-low-holes, or pot-holes, are passed and one as large as a crater is circled by the line, which gains grade with a horse-shoe bend. At 1 mile 36 chains, stiff grades begin. The line is maintained within a grade limit of 1 in 10, but to do this involves two back shunts, so as to work diagonally down the hillside. The first back-shunt is at 1 mile 64 chains, and the next at 2 miles 5 chains. The top of the incline is

PERFECT QUALITY. The Government overseer at the quarry, Mr. Angus Ross, subjects every stone to close and critical inspection, exceeding in severity that imposed in the case of material for ordinary buildings. So far, he has rejected stones only on account of surface faults due to heavy bush fires. Mr. Ross had practical experience in the lona marble quarries in Scotland, and when he was asked how the New Zealand marble compares with the Scottish stone replied: “It is far superior, both for quality and colour.”

THE TRAMLINE. What has made Kairuru marble of practical value is the tramline, six and a half miles long, which enables heavy blocks of stone to be shipped at Sandy Bay. The quarry is 1,130 feet above sea level, in extremely broken country, and it was found

reached 2 miles 34 chains from the quarry. As the load is with the grade, one horse can manage the haulage of a tram to this point, its services beingneeded mostly during the first mile, and at the backshunts. The important item of equipment is the brake, which has to stand very severe wear, the fourwheeled trams frequently carrying a three-ton axle load. At the incline top, the height is 621 feet abovc sea level. A loaded tram is attached to the wire rope running over a large pulley provided with two powerful hand brakes. Its weight easily draws up an empty tram, and any supplies required at the quarry. The bottom of the incline is 270 feet above sea level. Thence the line runs by a slight down grade over two bridges, and past the foot of the incline formerly serving the unsuccessful Sandy Bay quarry. The last mile skirts one side of a lagoon, and at the end of the line is a temporary wharf for loading stone upon the scows. The present method is the primitive one of dumping big

blocks of marble into shallow water, leaving them to be hoisted on board by the ship’s tackle, but a crane is almost ready for use, and timber is being cut for constructing a wharf, where there will be 4 feet of water at low tide, and 15 feet at high water spring tides. A bar at the entrance to the Bay limits the draught of vessels which can use the wharf, but the poit is easily worked by scows, which can economically handle the heavy blocks of marble. To cope with the demands of the Parliament Building masons, a daily output of 140 cubic feet is required. This can easily be maintained even under the present primitive conditions.

UP-TO-DATE METHODS. When the line consolidates, and the shipping facilities are improved, Kairuru marble can be placed on the market at a very reasonable price. The quarry is being managed on behalf of the Kairuru Marble Company by Messrs Hansford and Mills of Wellington, contractors for Parliament Buildings. They possess the most up-to-date stone-working plant in the Dominion, their machinery including a diamond saw, which does remarkable cutting work, greatly exceeding the speed of the gang saw method. The rough blocks are cut into slabs by bar and shot machines, and then squared with the diamond saws.

To bring Kairuru marble into the market as a commercially practicable building material has involved many disappointments, some of an extremely expensive sort, but it is pleasing to end this description of the whole business, from a remote hillside quarry to the busy masons at Parliament Building in the capital city, with a confident prediction that here is the sure beginning of a great industry.