THE KUMARA GOLDFIELD.

Kumara Times, Issue 1043, 3 February 1880, Page 4

THE KUMARA GOLDFIELD.

The following description of Kumara is furnished by Dr Hector to the reports of the geological survey of New Zealand, jast published, and is from personal observations made by him in September last:— _ The alluvial gold leads at Kumara are situated on the left-hand bank or south side of the Teremakau River, at the point where it commences to plunge into the narrow and deep valley which that river has excavated through the Tertiary claymarls to reach the sea. The erosion of this valley having been rapidly)effected as the fall of the river conformed to the changes in relative level of the granite barrier above and the sea margin below, isolated bends of the river Were left above the point where the valley becomes confined, and this portion of the old river-bed constitutes the auriferous leads. They have been covered by an enormous thickness of gravel drift, forming the terraces on the south bank of the river, so that no surface indication of their presence is obtained, and they have only been discovered and traced by sinking and tunnelling from the bank of the valley. They belong to a class of gold deposits similar to the sluicing-ground at Greenstone and Kanieri, and I have no doabt-ibat many other similar deposits will still be discovered in other parts of Westland where their presence is yet unsuspected by the prospector. The first notable discovery at Kumara was made in August, 1876, and since then seven leads have been found, several of which are, however, different portions of the same glitter or bid by-wash. The surface of the terrace in which the leads occur is from 300 to 850 feet above the level of the Teremakau River, while the level at which the auriferous gravel occonrs averages 230 feet; but, owing to the inequalities of the surface, the depth of sinking necessary to reach the auriferous deposite varied from 20 feet to 100 feet. The position of the leads owing to the bold fall to the Teremakau, is admirably adapted for ground-sluicing on an extensive scale, and it appears from the Warden’s report that there is no goldfield so well supplied with water, through head-races brought in by Government and by private enterprise. Bat the peculiarity of the ground lies in the circumstance that along the brink of the valley there is a high ridge, composed of gravels that are barren of gold, resting on a bottom of tertiary formation, which dips into the terrace, so that an open face for the ground sluicing operations cannot be profitably carried back from the main valley. Recourse must thereforefore be had to an artificial sludge-channel, carried through a tunnel at a sufficiently low level to connect the deepest parts of the auriferous deposits. Tunnels have already been put in by parties of miners, some of them being works of considerable magnitude and skilful enterprise ; but a sludge channel and tunnel at a sufficiently low level, giving a fall that would sluice off the the tailings from the deepest ground, and from the leads furthest back from the brink of the valley, would be a venture beyond the means of any party of diggers holding only a limited area of ground. There can be little doubt that without the,sludge-channel the present workings must soon become unprofitable, and cease ; while, on the other hand, if the whole ground could fie worked over by ground sluicing, I think there is every prospect of a tolerably permrnent and successful diggings being established.