DR. HAAST'S REPORT ON THE HOKITIKA AND WAIMEA GOLD-FIELDS.

Colonist, Volume VIII, Issue 794, 6 June 1865, Page 4

DR. HAAST'S REPORT ON THE HOKITIKA AND WAIMEA GOLD-FIELDS.

Me. Haast, the Provincial Geologist of Canterbury, has addressed a report on the Hokitika Gold-Fields to the Secretary for Public Works, The following are the main parts of the document, which we copy from the Lyttelton Times: — I started on the 26th of April to visit the gold-fielda north of the Holdtika. As this part of the province includes the most important portion of the gold-fields at present actively worked, a short description of the physical features will not be superfluous, the more so as the character and the nature of these gold-fields can only be understood when the changes in the physical geography of this part of ISew Zealand have been taken into account.

South of Lake Brunner, and on the western bank of the Big Hohonu and Greenstone rivers, a large granitic zone stretches to the Teremakau, forming, where the former trends towards south, a gorge through which that river forces itself. With this zone are associated metamorphic rocks of various character, partly auriferous. The greater part of the auriferous rocks lie east of this granitic axis, forming bold foldings. _ The same plutonic rocks are again met with in the Eiver Arahaura, about twenty miles from its month, stretching, as it seems, in an almost continuous line towards south.

West of this granite zone large alluvial, fan-like deposits are situated, inclining towards the sea, and having covered during their formation the highest points of the low tertiary ranges, which from the Grey river run southwards along the coast, stretching sis to eight miles inland. This alluvium consists of the debris of the dividing range and its western continuation, brought clown by the Eivers Teremakau, Arahaura, Hokitika, &c, which here have formed a fan, very much resembling the Canterbury Plains, with which we are so well acquainted. The lithological character of the boulders, of which this alluvium consists, gives us at once an insight into the nature of the beds from which they are derived. But by far the greater part consists of metamorphic and plutonic rocks, too numerous to mention, but clearly indicating that the longest course of the rivers went through rocks of that description, but also that the greatest denudation has taken place amongst them. It would be easy to collect within a few yards on these river beds, many varieties of granite, syenite, pegmatic gneiss, mica-chlo-ritic, and talcose schists, diositic porphyries, trap rocks, and a great diversity of slates, all derived from the ranges west of the central chain, and of which several are highly auriferous.

It is evident that, under these circumstances, the boulders, gravel, and sand by which, by far, as before mentioned, those alluvial deposits are composed, must contain a great deal of gold, but which, nevertheless, would not be worthy of being extracted, had not, by the subsequent changes in the configuration of the country, nature itself concentrated the precious metal in numerous localities by sluicing itself the original accumulations on a gigantic scale, and as ouly natural physical forces can act. This plateau, besides being intersected by those two large rivers, is nearly separated from the higher mountains forming the outrunning spurs of the Southern Alps by streams running either north to the Teremakau, or south to the A i-nhnurn, rivers. The consequence is, that for :i long period it has remained almost intact, till smaller watercoui'sos, derived from the surface drainage, began to form channels, of which the two principal ones are the main branches of the Kopitea and of the Waimea, which both take tl. eir source on that plateau itself, having the character of a swampy plain covered with manuka scrub and other vegetation peculiar to moist localities. Following down the main sources of both rivers from the plateau we soon arrive at a barrier, consistiue of young tertiary strata, through which the waters have cut their way, showing by the terraces that the process of denudation has been a very gradual one, or been accelerated or retarded

according to thephysical changes inoperation. As in many localities no denudation has taken place on the upper part of the plateau, the sluggish watercourses meandering through swamy or boggy ground, no gold is to be expected there ; and only descending for a few miles, where the alluvial capping has been extensively removed, and the gold contained in it has become concentred in the present watercourses, or in the terraces formed by previous channels, gold in payable quantities is to be expected. But by far the richest creeks are those which take their rise in the claymarl hills themselves. Those creeks which have a moderate fall, with an appropriate breadth, are those which yield tho richest harvest to the miner. Owing to the favorable nature of the bottom the greater part of the gold has been retained in them, and even the terraces yield a large quantity also. Thus, for instance, the creeks taking their rise in these claymarl hills, as Fox's rush, Greek gully, Nos. 1 and 2, falling into the Arahaura, the southern and northern branch of the "Waitnea, the Maori and German gullies forming tributaries of the Kopitea, have proved to be very rich, giving a fair remuneration to the mining population, But also the terraces on both sides, which, owing to their peculiar nature, present mostly come difficulties of obtaining water, so that the miner is often obliged to wait for rainy weather before he can strip his ground (for which, generally, he has not long to wait), are extensively worked with advantage, and will be still more lucrative when some new appliances are introduced, so that an ample supply of water can be brought to his assistance. It is true that the terraces are more or less patchy, but their fall being less than that of the present water channel the gold is heavier, and many claims were pointed out to me which are considered to be extremely rich,

The gold in all these creeks, like that in the Greenstone, is of the same fine scaly nature, which, considering the deposits from ■which it is derived, having travelled so far in a former large river, is easily accounted for. When the gullies are short and steep the force of the water has been so great as to sweep away the larger quantity of the gold, passing through the natural sluice; and I may only, as an example, instance

Caleyhan's Gully, falling into the Kopitea, in which the yield of gold, in comparison to other neighboring creeks, has been insignificant. In that creek only very large boulders are generally found, between which the goM has been retained; whilst the terraces above, descending with less slopes, are giving a far better yield and much heavier gold than the bed of that gully itself. As soon as the rivers lose their gorge-like character, approaching the sea, the extraction of gold begins to be not so remunerative as in their upper course, which is easily understood if we consider the breadth of the river bed and of the terraces bound-, ing it; the gold becomes finer and lighter, and although everywhere prospectors obtain the color, to use a mining expression, its working is no more payable. This is the reason why the Kopitea, flowing in a broad valley, has hitherto not given satisfactory results ; but, nevertheless, I have no doubt that some of the lower terraces in that river will yield ultimately a fair remuneration to the miner.

In many other localities, when the^ lower terraces are too poor to be worked with advantage, smaller creeks traversing theni, having again concentrated the gold contained in the alluvium by which they were formed, occupy a population of several hundred miners. Such gullies are found, for instance, in the Waimea, about four to five miles from the sea.

It is evident that a range which has furnished the material for such enormous auriferous accumulations must, since the formation of that gigantic fan, and even at present the denudation going _on uninterruptedly, set free large quantities of gold. Thus we may fairly expect that above the gorges of the Rivers Hokitika, Arahaura, &c,, new gold-fields will be discovered, where the precious metal, not having been subjected so much to the action of running water, will be of a more coarse and nuggetty nature, and, in fact, the gold obtained in the rivers south of the Hokitika, where the ranges approach nearer to the coast, is of that character, and may be considered as another proof that such a theory is more than a mere supposition. Therefore, we can anticipate that the gold-fields will eventually reach not only along the coast for a long distance, but also far back towards the central range behind the granitic axis, and that rich finds will reward the enterprise of our hardy mining population when it has once fairly penetrated into the interior. The circumstances that our present gold-fields are —what is technically termed poor man's digging —of a more permanent nature than many other mining districts in Few Zealand, because the gold being deposited as it were almost equally everywhere, a great deal of country, besides the terraces, will be found which may be considered to be more than only payable; the more so when roads of a more passable character will reduce the cost of carrying provisions inland. There is no doubt that the western ranges still continue to furnish auriferous alluvium, which, beside other evidence, we may conclude from the important fact that, for twelve to fifteen miles, and even higher tip, the shingle reaches of the River Arahaura are worked, giving in many instances a good remuneration to the miners. Thus, a 'comparison with the banks of the River Molyneux is obrious, and I should not be at all surprised if, when the former river is very low during the winter months, more extensive operations on its banks would not .generally yield satisfactory results. In summing up the evidence obtained during this journey, in which I have visited all the principal diggings, crossing several times over the clay marl ranges, and following some of the principal valleys from their very source to their junction, experiencing all that time a continuance of very rainy weather, I may state as my conviction that these diggings, for several years to come, will afford for a limited number of miners (several thousands) ample and advantageous occupation. It is true that many of the principal gullies will soon bo worked out, but the terraces remain, which, when once extensive races are brought into operation to work them hydraulically, will yield satisfactory results, and many leads will be discovered in those terraces, at present unknown. Owing to the dense character of the forest vegetation, and the absence of roads, many gullies are, without doubt, still in existence, which hitherto have escaped the exertions of the mining population to find new ground. Besides, one and the principal consideration has not been lost sight of, namely, as soon as passable roads will exist, present ones being only channels of semi liquid mire, intermingled with roots of trees, provisions will become much cheaper, and in consequence a great deal of auriferous ground, which hitherto has been reported not payable, owing to the high prices of provisions, will become remunerative as soon as good aud substantial roads reduce them to a reasonable standard. T/ith one word, the future of the West Coast gold-fields depends in a great degree on the nature of the roads the Provincial Government thinks fit to have constructed. Great are the exertions of the miners, those pioneers of civilization, who struggle manfully against all the disadvantages which the nature of this coast, its climate and vegetation, have placed in their way, so that every well wisher will join with me in urging upon you to assist them as much as it is in your power to change a wilderness into a flourishing country, which in many other respects possesses so many advantages that the Province of Canterbury will one day be proud of its western portion. My object being simply to give you a general outline of the character and the future prospects of these gold.fields, I cannot of course enter into a more detailed description, which I have to leave for future reports

Holdtika, May 10, 1865

I returned last night to this town, after having visited the country north of the Eiver Teremakau, and ascended the Eiver Grey as far as the Coal-measures. My favorable opinion has only been strengthened by this new visit to that most important coal-field, and I traced for a considerable distance the main seam on the Canterbury side of that river till it rises to an altitude of about fifty feet above the level of the water, thus insuring ample room and good success to any company which would undertake, to open coal pits in that region,

I have to refer you to my report, addressed, five years ago, to the Provincial Government of Nelson, in which I have given all the necessary details about these coalmeasures, to which I have nothing more to add. The low country between Lake Brunner, the Teremakau and Grey rivers, and the sea coast is of the same description as that south, of the first-mentioned river, ' and although comparatively a few miners are working at the Pnwa creek and some few other isolated localities, there is no doubt that ultimately more payable ground will be found in that quarter, which has hitherto not been so actively prospected as the country more to the south. '•■ln returning'to the Hokitika I observed several parties being actively at work, paddocking at high-water mark, and cradling the washdirt of a thickness of eighteen inches to two feet, on the sea beach. If such claims should prove to. be remunerative it would be impossible to foresee the extent to which such operations could be carried on; but at present I was unable to obtain the necessary information if the result can be considered satisfactory. As soon as my preparations are finished I shall start in a few days towards the headwaters of the Hokitika, and I hope to be able after my return to give you some favorable accounts of that interesting region.—l have, &c, (Signed) Julius Haast, Provincial Geologist.