IRON ORE IN NEW ZEALAND

Taranaki Daily News, Volume LIII, Issue 200, 2 December 1910, Page 8

IRON ORE IN NEW ZEALAND

PAHA PARA AXD TARANAKI. Dr. J. M. Bell. Director of Geological ' Survey in New Zealand, recently published in "The Iron Resources of the World" an interesting article on "The Iron Ores of New Zealand." Regarding the Parapara deposits, Mr. Bell says:— ) "The quantity of the ore in the three blocks Washbourn Block, Tukurua Block, and Onkaka Block—is enormous. It is impossible to estimate the exact amount of ore on any of the- blocks, since no operations beneath the surface have as yet heen conducted. The surface boundaries are evidently most erratic, and it seems natural to conclude that this irregularity may be taken as an indication of equally great complication in the boundaries beneath the surface. ! A rough estimate of the amount of ore visible"on the surface of the Washbourn ' Block gave about 23.560..17G metric tons. In the"Tukurua Block, the amount visible is not more than half that to be seen in the Washbourn Block, or, say, 11,000,000 metric tons; while in the Onakaka Block probably, very roughly, about 30,000,000 metric tons are to be seen. Thus in the three. blocks altogether an inexact estimate gives some 04,000,000 metric tons. The amount of ore in all the blocks may be much greater than the amount given, and it is not likely to be less. Only in the case of the Washbourn Block, where the surface areas have been very accurately ascertained, and where a stream cutting through the ' deposits gives some approximate idea of . their tmckness. can these estimates be considered to approach the truth. Everywhere in all three blocks great irregu- [ larit'y in thickness is apparent. Thus in places there is probably only a few feet of ore covering the under-lying rock, while elsewhere it may be measured j in hundreds of feet." With regard to the black sands on the . West Coast of the North Island, Dr. Bell says:—' "The deposits of iron ore occurring near New Plymouth are of a very different character from those at Parapara. They consist of magnetic iron sands, all more or less titaniferous, which owe their concentration in thick beds along the J seashore and inland for a mile or more ' to the action of the waves or wind. Beds ' of pure black sand, of very fine grain, are 1 interstratified with beds of feldspa'thic quartz sand, containing considerable 1 titaniferous magnetite, and with others ' practically free from iron. Sometimes • the demarcation between the various 1 beds is very abrupt and decided, again ; much more gradual. Considered lonaritudinally , the beds of pure black sarid '■ become lensoid and are replaced by others in 'which the iron constituent is lacking or unimportant, and aigain the i latter beds may be replaced by pure ! black sand. The black sand is supposed to consist of an intimate mixture of magnetic and ilmenite. It occurs very , widely distributed, and, there can be no ■ doubt, in very large quantities. It ap- ! pears at very frequent intervals along the coast on either side of New Plymouth, from the mouth of the Waitara river as far south as the mouth of the . Patea.

"The black sand has apparently been derived in part from the disintegration of 'hornblende-andesites and more basic volcanics, rich in titaniferous magnetite, and in part from tufa, representing the comminuted equivalent of these volcanics. Volcanks and tufas carrying titaniferous majnetite have a wide distribution near New Plymouth around the volcanic, cone of Mount Egmont. 'lt is quite impossible to give any definite idea of the quantity of titaniferous ironsanJ. Undoubtedly, however, it exists in immense quantities, and is measurable in millions of tons."