MINERAL RESOURCES OF NEW ZEALAND. [From a Correspondent of the New Zealander.]

New Zealand Spectator and Cook's Strait Guardian, Volume II, Issue 51, 27 September 1845, Page 4

MINERAL RESOURCES OF NEW ZEALAND. [From a Correspondent of the New Zealander.]

There can be no question as to the correctness of the position laid down, that " no colony can long or greatly prosper without articles of export:" it is in fact, a selfevident axiom ; but the great question is, — Are our mineral resources such as to invite the application of capital? On this subject there is much difference of opinion, for while certain persons ridicule the idea of the mineral resources of New Zealand, being of any value, there are others of considerable experience in such matters, who hold that it must be to her mineral resources that New Zealand must look as to the chief source of her future prosperity. It is to be regretted that there are few persons in the colony, who by habits of observation,

or by education, are competent to give an opinion entitled to any credit on this subject. An acquaintance with the general results collected and classified by Geology, must be our first- guide in the investigation of mineral districts, supposed to contain metalliferous deposits ; this knowledge alone enables the observer to judge whether any particular locality should, from the nature and arrangements of its rocks and mineral structure, be susceptible of containing within its bosom, workable metallic ores; it also indicates to a certain extent what mineral substances may probably be met with in any given series of rocks, atid in what particular locality such substances will probably be found. The application of these facts and principles, and their great value in our researches after mineral wealth, more especially in new and hitherto unexplored districts, must be known, since it not only shows the rocks in which mineral wealth is most likely to be contained, but also those particular portions of them, where the greatest degree of enrichment may be expected. These important laws, a knowledge of which is indis-: pensable to the scientific mining engineer, are entirely geological generalizations, deduced from a long series of observation and experience. Geology is essentially a practical science, and one of facts and observation, and although a knowledge of the external properties of the common rocks, considered as fragments, is a necessary introduction to the study of the earth, yet it must alwajs be remembered that mineralogy, properly so called, ought merely to be a preparation for geology, t and considered only as affording the characters "by which its mysteries are deciphered ; and that it is in the great arrangements of nature, in her lofty mountain chains, precipitous cliffs and deep ravines, and amidst the bold clifls and rocks which overhang the ocean, and not in the minute details of the museum, or of mineral collections, that the great facts and foundation of the science must be sought for and examined. Although an accurate geological and raineralogical description of the rocks occurring in the Northern Island of New Zealand, would be of the highest value, yet it is wholly impossible in the present state of our knowledge of the country, to produce any thing perfect on the subject. It is to be hoped, however, that our Local Government will not lose sight of this important subject, but that following the ex- \ ample of the United States of America, and lately, that of South Australia, it will direct geological and mineralogical surveys to be j made by competent individuals, of the most j important districts of New Zealand. The reports accompanying such surveys should be made to embrace every particular relating to Eccuomic Geology : such as the localities of useful building stones, of carbonaceous deposits, of deposits of Hrae, marl, gypsum, and slate, &c. ; of finer materials for domestic architecture, columns, vases, &c, and lastly, the localities of the ores of useful metals. The information thus acquired of the natural resources of the country, would be of the j greatest value, both to a«tual colonists, and to home capitalists; and being published and extensively circulated, would do much towards J ' inviting the application of capital," and thus " place the colony on a basis of solid commercial prosperity ." * On examining the general structure of the country, it will be found that New Zealand presents a highly interesting geological and mineralogical aspect, and offers a very beautiful illustration of the great principles of geology, as it presents a very complete assemblage of rocks, from the most ancient to those of comparative modern origin. These rocks are also disposed in such a manner as strongly to mark the physical geography of the country, and while its extensive line of sea-coast presents innumerable natural sections of the various rocks and strata, many of which after ranging across the island, are terminated in succession by bold cliffs upon our shores, opportunities equally numerous and instructive for studying the geology of the interior, are afforded by the numerous vallies formed by the larger rivers, many of which extend for many miles, and intersect the interior of the country. It may further be observed, that few countries present so many inducements for geological study, on the ground of practical utility, as are to be found in New Zealand. Those most valuable (because most useful) mineral substances, coal and iron, we possess, it is believed, in sufficient abundance. The ores of tin, (?) copper, lead, manganese, and other metals, have been found in several localities, and although the more precious ores of metals have not as yet been discovered, there exists reasonable grounds for supposing that they may yet be found. An immense number of rocks, from the primitive granite to the most

* As a model for a report of this kind, the writer would refer to the Geological Report on Cornwall, and West Somerset, by Sir H. De La Beche, Director of the Ordinance Geological Survey, and published by order of the Lords Commissioners of Her Majesty's Treasury.

recent formations, are found upon our snores, and there is reason to believe that mineral veins are numerous, and will be found to* include the greater number of metalliferous productions and known mineral substances. At first sight, New Zealand would appear as the place in which fragments and ruins from the rest of the globe have been confusedly heaped together, but when it is closely examined, its parts appear neither independent of arrangement, nor devoid of harmony and order ; nor do there exist any reasonable grounds for supposing that these islands are of more recent formation than other European countries, although, undoubtedly, volcanic action has been long and extensively in operation within them. The object of the present paper being, however, essentially practical, but brief allusion will be made to theor retical views regarding the formation of these islands, it appearing to the writer that a statement of facts relating to individual rocks, will be of much more value than any theory that can be propounded relating to their formation. It has long been known in Cornwall, that there is often much connection between given rocks in particular districts, and the productive mines in them, some rocks being considered more " kindly," as the Cornish miners term it, than others; they have observed with much care the kind of rocks or " country," as they term them, in which the ores they seek are principally discovered, and from local practice, they judge of the probability of finding such ores in given rocks, when the other conditions are also favorable. In applying this mode of reasoning in New Zealand, it will be found that in the few isolated instances in which discoveries have been made of the ores of metals, and also in the localities where mines have been opened, the circumstances under which the ores -are found bear considerable resemblance to those under which they are found in Cornwall and other mining districts. For such instances, the clay slate, or " killas," is generally found to be the enclosing stratum of the lode. It is very common, however, that granite includes within its bosom workable veins of copper, and tin is almost exclusively found in Cornwall in granite. A " plump," or somewhat decomposed granite, is that which is most esteemed by miners, particularly for tin, although the cases are by no means rare, in which large " bunches," of copper and tin ores have been found in hard granite. Respecting granite however, generally, it is not considered a favourable rock for copper, except it be in connection with slate. The consolidated mines near Redruth, in Cornwall, offer an excellent illustration of the geological position of one of the most productives mines in that county, which are situated at or near to the junction of the granite and the slate. At the western extremity of these mines, the mass of granite, which forms the )rominent hill of Carnmarth, dips below the surface at an angle of about 30°, and is overlaid by the metalliferous clay slate, or " killas," which is itself traversed by the porphoritic rock called " elvan." All these rocks, especially the latter, are intersected by mineral veins or lodes, which are highly productive of copper. The lodes have a direction nearly east and west, with a dip or underlie to the north, and are intersected at right angles in several places, by barren veins turned " crosscourses," chiefly filled with quartz and clayey matter. The width of the veins varies from 2 and 3, to 4 and 5 feet, and the chief produce is the yellow sulphuret of copper, a yellow copper ore, from which the great bulk of that metal is in most parts of the world obtained. The quantity of ore raised in this mine (consols) from June 30, 1838, to June 30, 1839, amounted to 24,289 tons of 21 cwt., sold at an average price per ton, of £6:10:10. The average standard^ of fine copper for the same period was £110 :2s., and the average produce of copper ores from all the mines in Cornwall was 7% per cent., whilst the average price per tori of ore from all the mines was. £5 :175. With respect to the value and average of the copper ores of as contrasted with those of Chili, Cuba, and other mining countries, I shall defer any remarks I may have to offer on the ores of those countries, and on the ores of New Zealand, to a future letter. — I am, Sir, your's, &c, F. S. P.

f The standard is the estimated value of the fine copper, per ton, considered from the various assays to be in the ores sold, less a fixed sum, (£2 : 10s.) per ton, allowed for the cost of smelting. The standard, of necessity, varies considerably.