Other formats

    Adobe Portable Document Format file (facsimile images)   TEI XML file   ePub eBook file  

Connect

    mail icontwitter iconBlogspot iconrss icon

The Pamphlet Collection of Sir Robert Stout: Volume 75

Mining

Mining.

The only mining going on at present is at the Mokau Coal-mine, which is situated on the Mokau River, about twenty miles from the sea, the river being navigable right up to the mine for vessels of 6 ft. 6 in. draught. This mine recently changed hands, and is now held by a Scottish company, known and registered as "The Mokau Coal-mines Syndicate (Limited)," which occupies under a sixty years' lease from the Native owners. The coal is of best class of pitch brown, and is rapidly gaining favour as an excellent household coal, and is also good for steam purposes. Eight distinct seams of this coal are already known, one overlying the other, and varying in thickness from 2½ ft. to 8 ft. The one now being worked is the fourth of the series, and 8 ft. thick, with a 6 in. band of slate in middle, but this band is rapidly running out. At the entrance to the drive, which runs some 15 chains into the hillside on an upward incline of 1 in 24, and is laid with the usual light mining rails, on which the trucks are worked by horses, the altitude above level of the river is about 40ft. The broken ground has now been passed through, and a face of 250 ft. of good sound coal exposed. It is proposed to sink on the lower seams to test their thickness and quality. Ten men are at present employed, and the coal continues to improve. The output for 1896 was only 1,943 tons. The operations of the company have been greatly hindered through loss of two small steamers at sea. Extensive improvements have, however, been made in the shape of new buildings, in relaying the lines with iron rails, and in page 31 pushing on the construction of a new air-drive, which, when finished, will be sufficient, to thoroughly ventilate all the workings for years to come. The company hopes to have one or more steamers in the trade again shortly. A considerable amount of work has been done both by the Government and coal company in snagging and opening up the river for traffic, which must also prove of great advantage to the lands on both sides for miles above the mines. A signalman has been appointed at the entrance of the river.

After a lapse of many years, boring for petroleum has been resumed. A new bore was sunk at Moturoa, close to the former bore, and at a depth of about 875 ft. oil was struck in considerable quantity. After fully testing this well, it was found that it was impossible to "shut off the water" from below, which seemed to rise and fall with the tide, thus indicating the existence of some fissure or other means of inlet, from the sea. The result was that only about two or three barrels, of 42 gallons each could be got per day, the oil rising at intervals only, and all efforts to pump having continuously failed. The company then chose a site about half a mile inland, and sank a bore to the depth of 1,534 ft. without, however, obtaining any oil. A third bore, which is still open and cased, was then sunk about a quarter of a mile from the first, and in this gas in a great volume was struck at about 908 ft., followed at 910 ft. by oil in great quantity and of excellent quality. Unfortunately, this was struck in soft papa, and after about twenty barrels had been pumped, and when the company was beginning to sell and to export its crude petroleum, the supply suddenly ceased. The gas, which had previously issued in sufficient quantity to enable the company to dispense with other fuel, ceased at the same time. The most probable explanation of this mischance is that the soft papa, of which the roof of the oil-seam is composed, having been deprived of the Support of the formerly imprisoned gas and oil, has collapsed, and thus choked the oil-seam lying in the vicinity of the bore. After further efforts to pump out the mud filling the bore, the company resumed drilling with the hope of obtaining another oil-supply at a greater depth. At 1,384 ft. oil was obtained in small quantities, and gas was thrown up in great volume. At 1,865 ft. the bore passed through the sedimentary papa rock and entered sandstone, which continued to the bottom at 1,976ft., where a large quantity of oil and gas was struck. The bore was cased with 6-in. casing down to 1,379 ft., where a thin hard streak of sandstone was found embedded in the papa, and was taken advantage of to shut off the water from above; but, unfortunately, water was again met with below this, and as no other hard stratum was passed between that and where the oil was struck, it was found impossible to shut off the water, although a 5-in. casing was sent right to the bottom. Packing was also tried several times. Each time the packer succeeded in shutting off the water for a few days when oil was pumped at the rate of about eight barrels per diem; the sides of the bore around the packer, however, kept crumbling away each time, and the rush of water from above effectually prevented further pumping of oil, and the company was reluctantly compelled to abandon this their third bore, the plant being unequal to deeper boring. Undaunted by frequent failures, another bore has been commenced about 100 yards further west, and at-time of writing this bore is down some 700ft., the strata passed through being similar to those in last bore, but considerably harder. It is expected oil will be struck in papa at between 900 ft. and 950 ft., but it will probably be necessary to go down 2,000 ft. to clear the papa deposit. The local directors are in favour of extending boring operations inland, including procuring a second plant and an additional staff of borers; but, as the difficulties are numerous and disappointments frequent, it is doubtful if the necessary capital will be forthcoming.

An enterprise like this, if successful, would enrich and give an immense impetus to the trade and importance, not only of the district, but also of the colony generally. Should the efforts now being made be abandoned through lack of capital, it is unlikely that further steps will be taken for many years to further test the value of these deposits, of the existence of which there can be no doubt.

lronsand is found in great abundance on the seashore from Mokau to Patea, a distance of 130 miles. It produces, when smelted, from 50 to 60 per cent, of iron of the finest quality. The first attempt to smelt this sand was made in 1848, and page 32 several trials have been made since, but the heavy cost of production and the absence of capital and modern appliances have, so far, retarded the industry. Strong efforts are now being made to remedy this by the introduction of outside capital and it is hoped these will shortly be successful.