1.-4

22

The above are only a few of the many anhydrous massive iron ores which exist in New Zealand ; and the next group consists of those ores which contain a large proportion of combined water, and are generally known as brown or hydrous ores. No. 6 may be taken as a type of the bog iron ore which forms in swampy localities, generally near the outcrop of the brown coal formation. From the quantity of sulphur generally contained in this ore, it is not adapted for making good iron ; but it could be obtained in considerable abundance, and under favourable circumstances for working, being generally close to supplies of coal and limestone. No. 7, from Eaglan, may be taken as an average sample of the brown iron ores from the tertiary coal formations, which occur generally aa ball-stones or concretionary masses dispersed through the shale, and can generally be obtained in large quantities wherever that formation prevails. As this ironstone is of great practical importance, a detailed analysis of its composition has been made, as follows: — (No. I,39s)Sesquioxide of iron ... ... ... ... ... ... 72 69 L Oxide of manganese ... ... ... ... ... ... -56 Alumina ... ... ... ... ... ... 1-16 Lime ... ... ... ... ... ... -27 Magnesia ... ... ... ... ... ... -69 Phosphoric acid ... ... ... ... ... ... -70 Sulphide of iron ... ... ... ... ... ... traces Siliceous matter ... ... ... ... ... ... G3O Water ( hygrosc °Pie ■■■ ••• ■•■ ■•• ••• ••• 'I'd (constitutional ... ... ... ... ... ... 1302 IOO'OO No. 8 is a hydrous hematite, formed by the decomposition of the hematite ore associated with the manganese veins alluded to under No. 5. This particular sample is from the Island of Kawau, but this ore is generally to bo found in thin, irregular veins wherever the sandstone formation has undergone decomposition into a form of laterite, which takes place to a very great depth in some places. As an iron ore, however, it would be very difficult and expensive to collect, unless to supplement a supply derived from better denned deposits of ore. No. 9 is from a deposit of hydrous hematite that occurs in the upper tertiary drifts at Parapara, in the Province of Nelson, but is also not infrequent in many other localities. The ore occurs as the matrix of a quartz conglomerate, but often containing large masses of nearly pure ore, of several hundred pounds weight. On breaking these there is frequently a kernel of undecomposed sulphide of iron, showing the origin of the ore to be probably from the denudation of a mineral vein. The deposit at this place covers about fifty acres in extent, and is 100 feet thick, and, as previously mentioned, is worked on a small scale for the preparation of pigment. Taking the foregoing as typical samples of the different varieties of hydrous iron ore, it now remains to notice the occurrence, in the upper secondary coal formation, of iron ores containing a sufficient percentage of carbonate of iron to entitle them to be classed with the black bands or spathic irou ores, which are generally considered the most favourable for the purposes of a blast furnace. Nos. 10 and 11 are samples of this ore, taken from two veins that occur along with coal seams at the Collingwood Coal Mine, and on account of their importance, I also give the following detailed analyses of their composition : — No. 1296. No. 1351. Protoxide of iron... ... ... ... ... 3523 ... 4038 Sesquioxide of iron ... ... ... ... 2577 ... 526 Oxide of manganese ... ... ... ... I*lo ... traces Alumina .. ... ... ~. ... ... 211 ... '40 Magnesia ... ... ... ... ... 194 ... -63 Lime ... ... ... ... ... ... 71 ... 66 Silica ... ... ... ... ... ... '90 ... -55 Phosphoric acid ... ... ... ... ...not determined...not determined Sulphuric acid ... ... ... ... ... traces ... traces Carbonic acid ... ... ... ... ... 2112 ... 2197 Sulphide of iron ... ... ... ... ... '41 ... '09 Water ... ... ... ... ... ... 19G ... '39 Organic matter ... ... ... ... ... 572 ... 1298 Silicates imdecomposed by acid ... ... ... 303 ... 1669 10000 ... 100 00 These ores occur at Collingwood under circumstances very favourable for their being worked, as they can be mined along with coal of the very finest quality that occurs in New Zealand, the only drawback being that the coal seams are not more than 3 feet thick, while the ore is from 10 to 20 inches. The coal measures are now being explored by a tunnel 700 feet in length, and so far as it has gone, they show an improvement from what w ras anticipated from the examination of the outcrop. Close to the coal mine there is abundance of fine crystalline limestone, belonging to an older formation; and deposits of graphite and also micaceous hematite, that might be useful in working puddling furnaces, are found in the same district. The area of country near Collingwood occupied by a similar formation, is about ten or twelve square miles; and as Golden Bay offers very favourable conditions for the erection of deep-sea wharves, I think it likely that this locality will be the first in New Zealand where the mineral resources will lead to the establishment of a manufacturing industry.