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DR. HECTOR'S REPORT ON THE COAL FIELDS OF OTAGO.

(From the " Daily Times," June 6.) Dr Hector's Departmental Report of the Geological Examination of Otago may be viewed in two aspects — the speculative aad the practical. The first, in common wiiJk all scientific abstractions, has charms correspondent with those with which all investigations are invested that are capable of being wrought into the mythical apt ideal. The abstractions of astronomy, as they do with magnitudes ant spaces that the highest efforts of imagination cannot realise, notwithstanding the hard, dry, and, to the ordinary mind, uninteresting trigonometric and algebraic processes from which they are derived, are • invested with the charm of poetry, because they suggest visions of the unseen and remote. Not only do the glowing planet^ rolling in their orbits round a commas centre, lead to the conception of scenes <£ beauty analagous to those of earth ; boft the brilliant stars, whose discs do not apparently enlarge though subjected to the magnifying influence of the most powerful telescope, while baffling human skill (• scan them closely, suggest to man system and suns, alike mysterious and innumerable. ' And so it is with Geology. lU revelations afford a glimpse of the earth's history in bygone periods, and place the changes through which it has passed, at immeasurable distauces of time from the present. The geologist finds embedded in strata, at varying depths below the surface of the earth, lossib which once were living organisms. He reconstructs their forms, and brings to light a period when creatures lived that could, not now find a resting place, nor food to sustain them. Yet they served their parpose, and many of them helped to construct and give order to arrangements, tte benefit of which we are now reaping. He finds substances adopted to Man's present necessities, " deep in unfathomable mineaj* — gold and silver, and precious stones 5 but far more precious to him than these, va3t deposits of coal, which, examined by the light of science, record a condition of the earth supposed to have been eminently calculated to develop vegetation. The strangely beautiful forms of flora which, have been found embedded in the coal deposits invest the carboniferous period with, an interest scarcely equalled by any other. Vasts trees, whose figured stems seemed to shadow forth columns more elegaui than those which in after ages formed the highest achievements of the Architectural Sculptors' art graced the forest. The Lepidodrendron and Calamite, witk gigantic Ferns and beautiful creeper* grew and perished in those lone wilds with no eye to gaze on their beauty, and no artist to immortalise their memory on canvas. Mutilated, crushed, broken and in fragments they have been handed to tv in these last ages — their very structure changed, but still imagination can reproduce them and thus invest the era whea they nourished with an interest heightened because so little respecting it is really known. To many persons, perhaps to most, this view of the labors of the geologist will present the greatest charm. But there is a hard practical aspect of the science which is infinitely more important if less interesting. All the mysteries which have been glanced at have been deduced, not from mere speculations in the closet^ but from active and energetic examination of the phenomena as they are. While the finding of a bone would enable a Cuvier to reconstruct in theory the animal «f which it formed a part, it is of far greater importance to know what the . land ia which we live contains— of what use its products are, how they can be obtained with the greatest ease, and what is their , value when obtained ; and this, so far m minerals are concerned, , is, the < apeckl work of the practical geologist. Whilq, therefore, to the man of science Djc Hector's report is exceedingly valuable ; jt is not less so to those who may be seeking to invest capital. His report is not » mere dry record of labor done, and of discoveries made. Under the head of Coalj" elaborate ,and careful descriptions are given, not only of the geological structure of the coal deposits that have already bee* examined and of their geographical position, but their value, as applicable to domestic and industrial occupations is described. Sixteen pages of the report are ..devoted te details of experiments made on the different kinds oi coal found in Otago, descriptions of them ; and the painstaking character of the investigations' may be

judged by the following brief outline •which is given of the "processes which " have been followed, which do not affect " extreme accuracy. In fact, in dealing " with a substance so valuable as coal, this " cannot be obtained, but still the results *• are perfectly reliable, and afford useful "information: —

I, In each case a fair sample of the coal was selected, finely powdered an»J sifted through amslin. The powder thus obtained whs then exposed to dry air till it had attained a constant ▼eight.

IL The water was determined by drying a weighed portion in a water bath at 212 ° until 3U> farther diminution in weight <vas suffered.

111. A portion was burnt in a plntinuta cnpsule, the resulting; residue being the amount of ash. ' The color of the ash was noted as mdi - cative ot the presence of su! phurate of iron- -the quantity, and quality of the ash being of great importance to the value of the coal.

IV. A portion of the coal, coarsely powdered, waa heated to a bright red heat ia a closed crucible* ao ai to imitate as far as possible the conditions existing in a gas retort or coke oven. The carbonaceous substance or coKe remaining after deducting the ash, is entered as fixed carbon its physical properties being also noted as representing the coking properties of the coal. The loss durifig thi9 process consists of volatile hydrocarbon* (euoh as coal-gas heavy and light oils, &c.,) and water, which latter being subtracted ieares the quantity of volatile hydro-carbons. Y. The sulphur was determined.

The physical characters of the coal were also noted -such as the color, structure, hardness, toughness, &o. — these bearing upon their commercial value as affecting their liability to breakage and production of " small" in catting or during transit. The specific gravity was also determined by accurate methods. Judging, by the variety of places in which coal has been already found in Otago, it would appear to be very widely distributed, and as in Victoria and some other parts of the Australian Continent, payable seams of ooal have not yet been found, a future for Otago may be predicted, probably of greater and more permanent prosperity than has arisen from her deposits of gold ; for judging by analogy when cheap and rapid communication between the coal pro. ducing districts and the seaboard is established, an export trade may be anticipated, increasing as the increased depth from which the coal is raised, enhances its value through its being of improved quality. It does not speak much for the enterprise of the inhabitants of Otago, that with such extensive coal fields the City of Dunedin has been nearly without gas during the last fortnight, and many steamers have gone to Picton with a short supply of fuel. It may be true that much", of what has >een discovered, is useless for the purpose 'of raising steam, or- perhaps for the, manufacture of gas, but all is not so. A passage from Dr. Hector's report may, therefore, perhaps be suggestive of a remedy for the evil. Referring to the Clutha Coal Mines which he says have been worked " during the last five years," he observes —

" They are situated on a Government " Reserve, and the lessee, Mr James G. " Lewis, has expended a large amount of " capital in their developement, and eni- " ploys the most extensive coal mining " plant at present used in the Province.. " Nevertheless, from various adverse cir- " cunistances, and principally the difficulty "of effecting the regular shipment of " coals to market owing to the risks en- " countered by vessels at the mouth of the " Clutha River, the mining has not been " carried on so vigorously as might have " been expected, and only a comparatively " small quantity of coal has as yet been " excavated."

After giving a further description of the arrangements made for transit of the coal, Dr. Hector then enters into a description of the strata, and concludes it by stating *! There are, therefore, in the above dis- " tance, six seams of good coal exposed in " the section, giving a total thickness of " 56 feet, but, doubtless, in some cases " the same seams are repeated by faults. " The coal seams are apparently very " regular, and generally have a roof of " tough shale. In only a few cases they 11 rest on fire clay, as more frequently the " floor is .of gravel stone. In several of " the gullies the coal strata are seen to <: crop out, preserving the same dip and strike as where seen on the coast, and " workings, I believe, were opened for a " short time on the bank of the Clutha " river, near the Kaitangata Bush, at a distance of two miles from Mr Lewis's 'pit. The coals could, therefore, be worked by shafts sunk almost anywhere in the terrace plain, and probably a better quality of coal would be procured in this " manner."

It is plain, therefore, that a ready com- . munication with the Clutha river would work as beneficially for Dunedin as improved means of transit between the northern collieries of England and London 'have done for that metropolis. In Fuller's time, that is, in the year 1661, only 200,000 chaldrons of coal were imported into London in the year.; in the year 1853 it amountec to neariy 3,500,000 tons, and since that time it has enormously increased, perhaps no mineral production is so valuable to a country as coal, und Dr Hector's labors tend to shew its commercial importance to Otago.

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Permanent link to this item

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Bibliographic details

DR. HECTOR'S REPORT ON THE COAL FIELDS OF OTAGO., Otago Witness, Issue 654, 11 June 1864

Word Count
1,655

DR. HECTOR'S REPORT ON THE COAL FIELDS OF OTAGO. Otago Witness, Issue 654, 11 June 1864

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