Art. LXIX.—On the Presence of Nickel in the Auckland District.
[Read before the Auckland Institute, 23rd July, 1877.]
In bringing this subject before the Institute, I have not done so with the intention of chronicling any valuable discovery, but simply to bring before the members the fact that we have the metal nickel existing in several parts of the province; nor can I lay claim to being the first to note the presence of this metal in New Zealand, as I find in the annual report on the Colonial Museum and Laboratory for 1876, Mr. Skey mentions its presence in troilite obtained in the geological survey of the Parenga River and Fox Glacier, Westland, by Mr. S. H. Cox.
My first acquaintance with the nickel of this province was on receipt of some stone from Mahurangi, about two years since, said to contain silver. This, however, was not present, but on further examination I found that the stone contained either nickel or cobalt, but the small amount at my disposal prevented my deciding in reference to these two metals. On receipt of a larger portion I succeeded in isolating nickel, but finding it in too small a quantity for commercial value, I did not pursue the matter further. A few months since I obtained some more stone of a similar character from the Kaipara, and found this to be a serpentine which also yielded nickel.
now made a careful research in all specimens to hand in which there were indications of this metal, and having made a quantitative examination, I herewith append it. The amount obtained is small, in no instance realizing one per cent., but the consciousness of its presence in the district will perhaps induce some of the settlers to more carefully note the mineral lodes in their neighbourhood, probably with the result of the discovery of larger quantities of the metal in question. The following are the localities where found, and the percentage in which it is present.
1. Loose stones obtained at Mahurangi, apparently of serpentine rock, and composed of silicate of magnesia, in which nickel is present in small and variable amounts.
2. Portions of a large rock-mass of serpentine outcropping in the direction of the Hotea from Mahurangi; in this I have found the largest amount of nickel, it being present to the extent of .49 per cent.
3. Serpentine obtained from a small stream near the North Manukau, Head in which nickel realized .47 per cent.
4. Calcite from Matakohe, stained in a peculiar manner with the hydrated silicate of nickel; the stone attached to the calcite is of the character mentioned in No. 1.
5. Hard greenstone from Papakura Valley, giving a trace of copper and nickel to the extent of .26 per cent.
6. Green unctuous clay from Waipu of a very peculiar character. In this I anticipated a larger proportion of nickel, but was disappointed, it being present only to the amount of .11 per cent. The colour of this clay is due, as in most of the other instances named, to protoxide of iron.
7. Foliated serpentine from Coromandel, in which there is a trace of nickel present.
The probability of this metal existing in larger quantities is, I think, very great, as but little time or attention has been devoted to the work of prospecting for other than the precious metals, and it is only through a careful examination of all minerals found that we can hope to have any success in the research. Respecting the probabilities of nickel being found in payable amounts, I would note that the deposits in New Caledonia of a silicate of this metal which have lately come into such notoriety are found in crevices in the serpentine rocks, and, as I have already remarked, my two largest results have been from serpentine; nor is it peculiar to this part of the world that it should be so situated, as Dana mentions several instances in which nickel is found in this rock. The efforts of a thorough research in the district between Mahurangi and Whangarei, through to the West Coast, may be well repaid should a body of stone containing a low percentage even be found, as in America ore containing only three per
cent. of nickel is mined with profit; while at Frieberg, in Saxony, even a much lower percentage is thought well worth the expense of recovery.
I cannot allow this short note to close without a few words upon a metal frequently accompanying nickel: I allude to cobalt. In the instances which I have already mentioned I did not find a trace of this metal, though I have succeeded in discovering it in this district in four distinct places in the shape of asbolite, the highest percentage yet found being 2.42 per cent., and this entirely free from nickel. I hope in the coming summer to still further investigate these deposits and bring the matter again before the Institute. With respect to the successful manipulation and refining of these minerals for commercial purposes in New Zealand, I am afraid very little can be done until we have sulphuric acid manufactured in the colony, as the importation of this article entirely excludes all chances of successful competition with the home refiners, and in consequence ores which might be utilized with profit must lie idly by awaiting the time when, from the cheap production of acid and its concomitant products, there may be a possibility of extending our manufactures and utilizing some of the raw material which the colony possesses.