THE COALFIELDS OF NEW ZEALAND

Colonist, Volume XII, Issue 1215, 31 August 1869, Page 5

THE COALFIELDS OF NEW ZEALAND

Last week Dr. Hector delivered a lecture on this subject in the New Ztaland Institute, at Wellington : —

After reverting to some points in his previous lecture, showing the uncertainty of all mining operations iv mineral lodes as compared with the mining of such minerals as coal, &c, which are obtained in stratified layers,—the classification of the coal deposits in New Zealand was described as being founded partly on geological age, but chiefly on the chemical composition of the coal. Besides the tertiary lignites, there are two coal formations —the upper, belonging to a period which is equivalent to the chalk or green sand of Europe, and the other being in beds which correspond in age with the Oolite. All the thickest seams of coal yet found are in the upper formation. The coal is of two varieties, the one containing a large quantity of water in its composition^ being inferior; while the other is a dry coal and of value equal to the best that is ever imported from Australia. Notwithstanding the different composition of these varieties of coal, the vegetation from which they have been formed appears from the fossil leaves that are preserved with them to have been of the same kind and to include plants that have some resemblance to those still existing on the islands. The older coal formation contains a different class of I plants, principally ferns; and only in one locality at Pakawau (Nelson Province) is there any blending of the two kinds of plants in the same bed. After illustrating this part of his subject, he described the distribution of the coal deposits throughout the Colony, and gave a particular ac( ount "of all localities where coal had actually been worked. Commencing with the Kawa Kawa mine at the Bay of Islands (Auckland Province.) This mine it appears is worked to considerable extent and about 2000 tons of coal is extracted every month, principally for the supply of the crushing mills at the Thames diggings. The seam was originally discovered by Maoris while gum-digging in 1863 ; but it is only lately that it has been systematically worked. Its thickness is from 10 to 16 feet and the formation probably extends over a very large area of country both north and south. At Wangareri (Auckland) the same kind of coal is worked, but its character is inferior. At both places a large expenditure has been incurred in making tramways, barges, and wharf accommodation, but both mines are worked level free. The Waikato (Auckland) coalfields were next desorihed, and the very large extent of country over which this coal is found, pointed out. In quality it is intermediate between the brown coal and the hard dry coal, and has been largely used for many years past by the steamers on the Waikato river. The region from the Mokau river to the source of the Wanganui was also pointed out as a district where there are extensive coal beds; and also the East Cape country, but nothing very definite was yet ascertained about either of these localities. In the South Island, the Pakawau, West Wanganui, and Aorere coalfields (all in Nelson Province) were described as being very extensive, and the seams opened in some places, valuable, but rather inaccessible. . . . The plumbago was described, as probably being derived from the altered coal seam. The coal is inclined to the westward and extends from the sea and up to an altitude of 1500 feet, * This is the characteristic feature of ail tli« Weat

Coast coals which are Of superioil 'quality. After mentioning the coal strata at the soured bf the Wangapeka and jKaramea rivers, (Nelsdn)> which has been much disturbed and altered by dislocations the Mount Eochfort coalfield, (Buller river, Nelson), was dflscribed. There is only one main seam, ten to thirteen feet in thickness, resting on a lofty plateau of slate and granite rocks and covered only by a thin coating of gravel and sand which has been cemented into a rock which is as hard as granite. Coal seams are also found at lower levels near the sea, bufc the quality is inferior. Some day the Mount Bochfort coal will be worked, but for the present it is too inaccessible. The Grey river coalmine (Nelson) was next described in detail. Dr. Hector stated that this mine is one of the most striking he has seen anywhere The seam is over twenty feet thick and some of the galleries already run for 1100 feet, with that height. The coal is excavated with great facility at small cost, as the mine from its position requires no pumping, while the coal trucks run out of themselves to the barges." The consumption at present being about 1000 tons per month. The seam has been observed at several points and is supposed to underlie a 7ery large area of country. There is no clear evidence of the existence of more than one workable seam, but it rises to an altitude of over 2000 feet in Mount Davy. It is also continued in the south on the Canterbury side of the Grey river, but dips in that direction below the level of the surface. The distance of the mine from the sea is seven miles. Unfortunately the river is not suited for larger vessels than those drawing eight feet, but something might he done to improve it in this respect. The Preservation Inlet coal field was next mentioned, and it was stated to he part of the came field that extends through Southland into Eastern Otago. The value of the coal is variable, but on the whole good. The seams are in some places of great thickness. Beside tho valuable coal fields in the east of Otago, which supply Dunedin to a considerable extent with fuel, brown coal is found in almost every part of the Province of Otngo except the Wakatipu Lake basin, but these seams principally belong to a newer formation. Forty miles north of Dunedin the Upper coal formation again commences, and, running north, skirts the eastern slope of the mountains in broken patches, being found at several points in the Province of Canterbury, and re-emerging on the coast of Motanau in the Amuri country. Newer basins, containing inferior coal, also occnr along the Canterbury and Nelson mountains as in Otago. In concluding his lecture, which occupied two hours, Dr. Hector stated that New Zealand must be considered as, on tho whole, well supplied with mineral fuel. Certainly coal of the most valuable description was confined to limited and not very accessible areas; but still there is nothing to prevent their being profitably worked for the supply of our steam service ; but the great point for congratulation is, that throughout almost every part of these Islands, coal of a practically useful description is to be found within a short distance. Those who know the character of the tieeless mining district of Otago can understand how impossible it would have been for the diggers to carry on their operations in many of the upland districts had it not been for this wonderful provision.