Quantity and Quality of the Parapara Ore.

Progress, Volume III, Issue 9, 1 July 1908, Page 302

Quantity and Quality of the Parapara Ore.

It becomes the main question, what is there at Parapara in the shape of iron ore ? The Karamea district is according to the Geological Bulletin (No. 3, of the new series)

243 square miles in extent, and over the whole of it there is iron ore more or less. Of that ore, the best in quality, and the most in quantity is to be found in three outcrops, viz : the Washburn block, the Tukurua block, and the Onakaka block. The ore of all three, says the Bulletin, is apparently the result of oxidation of ferrous carbonate, the general quality being high, the deposits in the Washbourn block showing, however, ore of higher grade than the others. Mineralogically considered, the ore is mainly limonite, though partly gothite, and possibly turgite. The quantity of ore in the three blocks is " enormous, though it is impossible to estimate the exact amount of ore in any of the blocks, since no operations beneath the the surface have as yet been conducted. A rough estimate" — we may remark, an estimate that bears the stamp of the most careful, conscientious calculation and computation — " of the amount of ore showing on the

surface of Washbourn block, gave 22,691,762 tons. The amount of ore in this one block may be much greater, and it is not likely to be less." The quantities of ore in the other two blocks are such as to satisfy " the most exacting iron-seekers." The area of the Washbourn block is about one mile [square, and the Tukurua is about the same, the Onakaka being two miles long by a mile and a half broad. In these areas the deposits are extraordinary, as may be seen from our illustrations. The ore occurs in the creek beds, it lies scattered over the hill sides, it is disclosed by great rents in the mountains, it stands obtrusive in huge cliffs. A great deal of it is covered with timber of the dense character special to the Dominion, its quality proclaims itself to the eye of even the tyro, it lies for the most part in ridges, standing between streams. The great fact is that no search is required. The miner has but to scoop the ore in. What of the quality ? Firstly, for the impurities of which there is a small percentage, they never occur in the Parapara division in quantities sufficient to prove refractory in the manufacture of pig iron. Then as to the percentage of iron. Standards of value are — turgite, containing 662 per cent, of metallic iron ; gothite, 62- 9 ; limonite, 598 per cent. Now, it is on record, that from a sample of ore taken to Melbourne, so far back as 1870, pig iron was made experimentally containing 97" 62^ per cent, of metallic iron. Referring to this experiment the Bulletin of the department abcve quoted, says, that none of the extraneous elements " occur in such proportions as to render the metallurgical treatment difficult, or the commercial products inferior to those turned out by many of the leading iron-producing mines of the world." The detail analysis is of course more important. There is one for each of the blocks. From the Washbourn block, 34 samples were taken, with care to keep as near the average of the localities as possible, and the iron contents ranged from 58' 18 per cent, to 407 1 with an average of 5T79 per cent. The remark of the Bulletin is " In order that the exact chemical nature of the ore body might be known, complete representative sampling was made of every available part

of the ore deposit in Washbourn block, and the analyses made therefrom have shown the splendid quality of the ore in a very striking manner. Hydrous iron-oxides with over 50 per cent, of metallic iron may be considered of high grade ; with 40 to 50 per cent., of medium grade ; and with less than 40 per cent., of low grade. Twenty-nine of the 34 showed over 50 per cent, in the iron content, and hence the ores were high grade limonites, while the remaining five — between 40 and 50 per cent. — represented medium grade ores. " From the Tukurua block, seven samples were taken, ranging from 59" 35 to 43*79, with an average of 50"4. From the Onakaka block forty samples were taken, ranging from 52- 44 to 24-99, with an average of 45*17. Out of the 40 samples, four were of high grade, 34 were

medium, and only four of low grade — a fact which compensates much for the great variety of observed quality within short distances. There is a fourth block, the Pariwhakaoho, but it is not extensive, and the quality of a sample did not show more than 470 3. In addition, there are minor occurrences of ore all over the district, but they are valuable chiefly as showing possibilites for the future, after search, than for present developments. The supply of iron in the big blocks then is immense — extraordinarily ssando — and the quality is of high average.