METAL FOR THE ROADS.

New Zealand Herald, Volume XLIX, Issue 15110, 28 September 1912, Page 8

METAL FOR THE ROADS.

THE MOUNT EDEN QUARRY.

SUPERIOR QUALITY OF STONE.

Mount Eden Quarry -will at last yield to the city engineer's department a quality of stone superior to that hitherto quarried for the making and maintenance of local roads. A few weeks ago the quarrymen, on reaching a lower level, found an excellent material commonly known as volcanic basalt. This stone extends right through the* quarry and the supply will, therefore, last for many years to come. In order to judge of its powers of resistance, Mr. W. E. Bush, the city engineer, subjected an ordinary specimen, together with many specimens from quarries in the Auckland province, to what is known as an attrition test. Briefly, this is the placing of the stones .in a cylinder arrangementwhich acts on them in a way similar to the pressure caused by general traffic and erosion by water. The results, in the opinion of Mr.'Bush, proved conclusively that this new Mount Eden metal was better than all the other specimens submitted. although two of the other samples came verv close to the Mount Eden ones.

A Hkrali) representative visited the quarry yesterday and saw the men taking out the, new metal, the appearance of which is akin to the material used in the Old Country, although, comparatively speaking, it is not of the same hard wearing quality. But judged by other New Zealand metal, Mr. Bush says that it is not likely to entirely grind to dust as the kind previously used, in fact its cementitous value is very high, or in other words, when ground it forms a natural cement which .cakes in a solid way, tints making an excellent road material. In future, this new material will be almost entirely used for road construction in Auckland and district.

.-Another interesting feature at the Mount Eden quarry is the rotary furnace, an ingenious device for heating the broken metal before passing it into large buckets, which are then dipped into tar, next screened, then emptied into carts to bo taken away to the roads which are being made with this material. Park-Road, from the Grafton Bridge to Park Avenue, has been made with this metal, and Stanley-street is at present being laid with the same. The cost is' almost double that of the ordinary plain metal, but in the opinion of all experts it is stated to bo worth the expense. The new machine requires a little more adjustment before it will be thoroughly automatic.