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The Pamphlet Collection of Sir Robert Stout: Volume 50

Minerals

Minerals.

Gold.—Coming now to less ethereal resources, we have first to deal with those under the earth, and of these the most important hitherto has been gold. As shown in our historical sketch, gold-mining made one great effort to advance the colonization of New Zealand, and having fulfilled its mission sank into comparative insignificance. The country has now been well prospected, consequently there is little chance of further discoveries of alluvial diggings of an extensive character. The ordinary river workings are rapidly coming to an end, but the hydraulic workings in gravel and cement terraces will last many years, and quartz-mining is supposed to be only in its infancy. We cannot, however, calculate on any material increase on the present yield of gold; the decrease in alluvial diggings will balance any increase that may take place in quartz-mining, for the alluvial mines are still yielding two-thirds of the gold obtained in the Colony.

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Silver.—Up till 1882 £100,755 worth of silver, the produce of the Colony, had been entered for exportation, the greater portion of which was extracted from the Thames gold, which contains about 30 per cent, of silver as an alloy. Silver has also been found combined with lead and other minerals in Nelson and Westland.

Goal.—Until the predicted revolution in mechanical science takes place, coal will undoubtedly be the most important mineral in the Colony in the future, so it is satisfactory to know that the supply is practically inexhaustible. Coal of various kinds occurs all over the country at short intervals—the geological maps are bristling with black marks indicative of its presence. Instead of being a boon, this superabundance of fuel has hitherto been a real difficulty and cause of expense, not only to the Colony as a whole, but to private individuals, for the industry is being developed in all directions much in advance of our requirements.

The portions of the Collingwood, Buller, and Grey Coalfields that have been surveyed are estimated to contain 200,000,000 tons of the best bituminous coal, a quantity equal to the present consumption of the Colony for nearly 400 years, assuming that nothing but this class of coal was burned. The area of the Kaitangata and Tokomairiro field, which yields the best class of non-bituminous coal, is about 60 square miles, and the estimated quantity, 768,000,000 tons. With the exception of the Collingwood field, which has water communication, all those just mentioned are opened up by railways. They are all in accesible situations, and, except at the Grey, nearly all the coal is procurable without sinking. Railways have also been constructed into other extensive coalfields in Auckland, Canterbury, and Otago. For example: the Night-caps field, in Southland, estimated to contain 100,000,000 tons of page 33 the Kaitangata class of coal; and the Green Island field, with much the same quantity of brown coal.

Oil Shales and Oil.—Lighting comes naturally after fuel, and to provide it nature has supplied us with the raw materials in the form of oil shales and mineral oils. Shales have been discovered in Auckland, Nelson, and Otago. They are of good quality, and the deposits are believed to be of considerable extent. In addition to oils of various kinds, these shales are rich in gas. I have no doubt the deposits at Orepuki will be utilised for this purpose as soon as the railway is opened. The mineral oils have been found in Taranaki and Auckland, some of them are of good quality, but a steady supply has not been obtained.

Iron.—In conjunction with coal, the most important mineral to have in any country is iron, and New Zealand seems to be well supplied. Iron ores of various kinds have been found all over the country; but the information with reference to them is not very complete, no attempt having been made to work any of them, except the iron sand. The extent of some of the deposits has, however, been ascertained. The quantity of haematite ore, exposed at the Parapara River, in Nelson, is estimated at about 53,000,000 tons, and there is another bed in the same locality 60 feet thick. Veins of somewhat similar ore, 6 feet thick, occur in Canterbury and the Wakatipu district. Black band and clay ironstones, which are the ores most easily reduced by the common methods, have been discovered at various places in both Islands. In most cases coal and lime, the materials required in smelting iron, are found in close proximity to the ores.

Copper.—Copper has been found all over the Colony, from Auckland to Otago, but more particularly in Nelson, which is veritably the home of minerals. A mine has lately been opened at the latter place which page 34 promises to be a success, the deposit of ore being about 5 feet in width.

Lead.—On a recent visit to the West Coast I was shewn a splendid sample of lead ore from Mount Rangitoto, similar in every respect to what I had seen worked at Home. It was looked upon merely as a matrix in which silver was found and considered of little value. This is reversing the order of things. In England, the occurrence of silver in lead ore is considered incidental, the latter being the more important metal. Lead ore is well dispersed throughout the Colony, but the extent of the deposits is unknown.

Tin and Zinc.—Tin has been discovered in Otago and at Reefton; but the samples hitherto obtained have been very small. Zinc occurs in Auckland, Nelson, and Westland.

Minor Metals.—Among less important metallic ores discoveries have been made of platinum, mercury, nickel, cobalt, antimony, chrome, and manganese; the latter is worked successfully at the Bay of Islands, 10,719 tons of the ore, valued at £39,423, having been exported in the five years ending 1882. Manganese is extensively used in the new processes of steel-making.

In many cases small specimens only of the minerals have been found, which of course gives no clue to the extent of the deposits, but it is reasonable to assume therefrom that deposits exist. There must be a stock where the sample comes from.

Clays.—Coming nearer the surface of the earth we find clays, building stones, roofing slate, lime, and other building materials. Clays of all kinds are very plentiful throughout New Zealand, and there seems to be a variety for every purpose, from common bricks and tiles to chinaware and tobacco pipes.

Building Stone.—Building stone is also everywhere present in large quantities and of all kinds. The hard- page 35 stones are represented by granite in Nelson and the Sounds, and volcanic rocks near Dunedin, Christchurch, and Auckland. One of the best and easiest worked is the well-known Port Chalmers stone, the supply of which is practically unlimited. Freestones are also plentiful and well dispersed, particularly in the South Island. The white granular variety, of which the Oamaru stone is the type, occurs in immense quantities right across Southland, and all along the front range from the Kakanui to North Canterbury. They are all remarkable for uniformity of colour and consistency, and the Mount Somers and Southland varieties are comparatively hard and impervious.

Marble.—Marble of various colours and consistency has been discovered all over the South Island, and in several places in the North Island. Small specimens of statuary marble have been found on the West Coast, but no regular deposit. Many of the best of the commoner kinds occur in accessible situations, notably at Caswell Sound, where a quarry has been opened, and in several places in Nelson, Canterbury, and Otago.

Slate.—Roofing slate, equal in quality to Welsh, is found in the Kakanui Range, commencing at Otepopo, and running inland for a great distance. The deposits cover an immense area, but it is not clear that a large proportion of marketable slates can be obtained readily, the rock on the surface being considerably shattered.

Limes.—Limestone, suitable for burning, is almost as plentiful and widely dispersed as clay and building stone, but the hydraulic varieties which make the best mortar are not so common. The best and largest deposits occur in Auckland, and on the Otago Peninsula. A large bed of pure chalk—the best material for Portland cement—has lately been discovered near Oxford, in Canterbury.

Minor Minerals.—Among the minor non-metallis page 36 minerals used in manufactures and the arts, which have been found in New Zealand, are plumbago, sulphur, gypsum, magnesia, alum, flint, felspar, asbestos, meer-shaum, and talc.