REPORT BY J. G. LEWIS, Esq., ON THE CLUTHA COAL FIELDS.
Clutha Coal-field, June 21st 1859. To His Honoh, Captain Cargill, Superintendent of Otago. Sib— Having brought the important task which your Honor was pleased to confide to me to a successful termination, I beg most respectfully to lay before you a report of the operations, showing the nature and quality of the coals, the capability of the mine* and the cost at which it may be delivered on the banks of the Clutha Itiver.
In a former report I expressed an opinion that the site of our operations was part of an extensive coal-field. Upon a closer examination this opinion is corroborated by several
facts; the shaft we have sunk being situated nearly on the extreme southern boundary, whilst the original Coal Point, which lies about four miles to the northward, is nearly on the northern one. Between these two points coal is visible on the sea beach at several places, but whether it is an additional bed, or a part severed from the main seam, cannot at present be stated with certainty; but the appearance of the accomjmnying measures seem to indicate that it is an additional one. At the northern point greater regularity in the measures prevails, and the coal possesses one decided advantage in having a firm compact roof, formed by the conglomerate sandstone, which' is here a continuous rock, whilst at the southern point it lies in immense boulders upon the top of the coal. In other respects there is a great similarity in the seams as to quality and thickness. An opinion generally prevails that the black beds seen at low water, considerably out to sea at the northern point, are beds of coal —this, upon a close examination made at low water, is found not to be the case—they are beds of blaize which form the floor of the coal, the whole of which has been denuded up to the beach. The shaft is planted, as shown by the accompanying rough sketch and section, upon a high cliff, at a distance of 70 yards from high water mark, and about 15 yards from the boundary line between sections 2 and 3, Coast district. The following is a descending scale of the measures there proved :
The aggregate thickness of clear coal is about, 18 feet 6 inches, which is greater than that o*' any seam in Great Britain with the exception of the Ten Yard Coal of South Staffordshire. The seam dips regularly under the sea to the south-east at an angle of 8£ degrees. It is sometimes bare and visible at low water to a considerable distance, but is generally covered with sand. The nature and quality of the differenrbeds of the seam is as follows: — Ist, The top coal, No. 4 on the section, 10 inches thick, is a black, rather dirty-looking coal, much mixed with earthy matter, pyrites, and sulphur, and may be considered as of very little value. 2nd, The black coal, No. 5, is a clear, long grained, black coal, 2 feet 9 inches thick, burns well and seems suitable for smithy purposes, and would probably make good cokes. Both. this and the top coal are of a perishable nature.' It was from these two beds, and a very smalt portion of the upper splent bed, that the parcel furnished for trial to the "Qneen" steamer was obtained. This, coupled with the fact of its having been quarried from the sea beach where it had been washed by the salt water and exposed to the action of the weajther, is sufficient to account for the unfavourable report made by the engineer of that steamer. The parcel furnished to the " White Swan" steamer, was a mixture from all the beds, and was extracted from a spot where the salt water could not reach, but was exposed to the weather. v. 3rd, The upper, middle, and lower splent coals, Nos. 6, 7, and 8, although occasionally separated by distinct partings, may be considered as one bed. It is scarcely distinguishable from the splent coal of Fifeshire—is of a greyish-black lustre and conchoidal fracture. It forms together a fine valuable bed, 10 feet 4 inches thick, burn 3 well, makes a clear cheerful fire, and affords a strong glowing heat—is durable, and possesses the property of retaining fire when smothered up for several days. The whole of the cargo shipped by the " Ann Jane" lor trial has been mined from this bed.
4th, Black has, No. 9— a hard, bituminous, black clod, 6 inches thick within the mine, but on the beach, when first cut through, 20 inches thick; and there contained a few imperfect fossil plants. sth, The bottom ,coal, No. 10, is a fine bed, 4 feet 7 inches thick, appears to be of a superior quality, approaching veigc near to the Cannel coal of England and tEe Parrot coal of Scotland. It will probably prove a valnable coal for gas, baker's ovens, stoves, and other purposes. Being under water, great difficulty was experienced in cutting through to prove it. When the mine is effectually drained, this might be advantageously worked with the other beds.
The coals from all the beds emit a slightly sulphureous smell when first placed or broken upon the fire ; but this may not be the case when they are worked at a greater distance from the sea. The ashes being white affords good reason to hope this ; those from really sulphureous coals being red. As regards the capability of the mine to produce quantity, it must be obvious from the great thickness of the seam and the extent of unbroken ground, that any demand that is likely to arise for some time' to come may be supplied, supposing capital and skill to be brought into action.
The only real difficulty that presents itself arises from the weak, heavy, tender nature of the roof, rendered doubly so by the weight of water in the quicksand. This is n serious difficulty, and unless it can be removed may prove an insuperable one. That the quicksand and coal are both supplied with water from the same source is evident from the fact that when the coal was first touched by forcing a crow har through the quicksand, a strong rush of tar water immediately followed; and in cutting through the joints in the coal, they are found full of sand from above. This being the case, it would be possible to find the feeder and cut it off, there being prop wood of the besfc description. In estimating the probable cost of the coal on the Hirer bank, the expense of conveying it from the mine to the river forms a very heavy item ; and should any considerable quantity be required, it would become necessary to substitute a cheaper and more expeditious mode of conveyance than by bullocks. The cost of a metalled road would be euorraoua on account of the absence of material. A railway then appears to be the only alternative; and with a view to ascertain the practicability of one, I have carefully examined the nature of the ground and taken such levels as are necessary, and find it is admirably suited for a line, which may be carried from the mine delivery on a level to the river, except down the hill, near jetty, where a self-acting incline plane might be advantageously worked. A firm well-framed timber railway with iron bands forms a cheap, serviceable, and durable line. The cost of carriage by such a line would be reduced to one-third of its present amount, including the interest upon the outlay. I have estimated as nearly as circumstances will allow, the cost, including the" Government royalty and a fair remunerating profit, at which the coals may be offered on the banks of the Clutha River, and have taken it,in two ways.
Ist, Supposing the coals to be continued to be worked upon the present imperfect system, and to be conveyed as at presently bullocks. Iv this case a less price than 20s. per ton would not be remunerative.
2ud, In the event of an adequate capital being employed, the most improved system of management ami working to be introduced, and railway kid down, with proper conveniences for shooting the coals into the vessels, the price may be reduced to 12s. per ton. I remain, with due respect, Your Honor's most obedient servant, , r ' Jas. Gjsoi- Lfiwis'.\\
k °- * feet, inches. 1. Turf, day earth, and clay ... 18 6 2. Sand of various colours, very .loose 13 io 3. Quicksand with water ... 3 3 4. Top coal 0 10 5. Black coal 2 9 6. Upper splcnt coal ,3 7 7. Middle splent coal 3 3 8. Lower splent coal 3 6 9. Black bas & Q 0. Bottom coal 4 7
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REPORT BY J. G. LEWIS, Esq., ON THE CLUTHA COAL FIELDS., Otago Witness, Issue 397, 9 July 1859
REPORT BY J. G. LEWIS, Esq., ON THE CLUTHA COAL FIELDS. Otago Witness, Issue 397, 9 July 1859
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