Our Coal Mines.

Otago Witness, Issue 1581, 11 March 1882, Page 12

Our Coal Mines.

A TRIP TO THE WORTH.

By Vagob.

Springfield — Continued,

Having seen everything about the workings that they seemed willing to show us, and sufficient to enable us to understand the general system of .working ,the seams, and tho apparatus used for that purpose, it may be that I, am in a measure competent to express an opinion upon ths merits of the colliery and its prospects, as well aa to describe the system in use j and whilo endeavouring to do so, I hope I may be forgiven if I touch upon any matter which has no direct bearing upon tho subject in hand. First then, the seam, as 1 said, is a small one (the upper one we did not see), and the quality of the coal is nearly equal to that of Shag Point, thus ranking amongst the best of our brown coals. It is excellent for household use, but, like all our East Coast coal, very inferior for steaming purposes to that imported from Newcastle or Westport. It is, however, used on the branch railway, whei c it seems to give satisfaction. The cost of carriage to Christchurch is very considerable, coming up to about 8s pur ton. Heavy that— too htuyy. Still all they can produce is ivjarWy bmiH* , fit least so Mr Vale said, nnd_ ho .should ki <iw. New it seems to me that ir. this inattoi Jjio Company, like every other coal company in Otago and Canterbury, has a real grievance. These heavy railway rates are a serious drawback to the coal indxistry, acting like a,

powerful brake. They should' be' ''largely reduced, arid to that ( end ' all the coa^ companies should join in a united attempt to influence the authorities. Perhaps they might then succeed, singly they never will : and if the rates are not reduced they will, I am afraid, soon find most of their town trade cut off by the Westporfc coal, which is so much better for steaming that the few shillings a ton extra it costs won't debar it from supplanting the local product. The public also have a strong interest in the matter, for cheap freightage means cheaper coaj, so that they have the same interest in getting, the tariff amended as the coalowners and miners ; and the Railway Department, if it is alive to its own interest, will reduce the rates, because were they lower more coal would go over the lines, thus more than making up the deficiency ; so the railway companies at Home have found, and there i's nothing to hinder its being so here. To return. There is no communication between the two 'seams, other than the shaft, nor is there any second outlet for either. Work, however, as we have said, is being pushed on vigorously with tho former arm, but I did not see or hear of any special push being made for the latter object. Certainly, it will have to bo done. The law will compel the doing of it, even if self-interest fails. The principle on which the lower seatn is 'worked is a modification of that, known 'as " stoop-and-room, and this is it as it is pursued in the large collieries at Home. When a shaft is coaled, as it is termed, levels are started _on both sides. These are driven for ,a little way, and ■ a heading is .started ; from each, #at right angles, and driven straight to the rise. A cross-cut connects them after they have

proceeded some distance, thus leaving a square block of coal of considerable size, called the bottom. stoop. "The object ,of. Jhe stoop being, left Very large is to keep the, shaft pecure. The levels "go on, and more headings , are started, more* crosscuts are driven, and more stoops are i left,} smaller, thougli, than .the bottom one. Thu! the work proceeds, headings and 'levels are driven farther and . farther,. ;more land more stools ar,e left, till, the .boundary has been readied 'all around, or till' the distance, from, the, shaft ' becomes ( too great' ,for, economical; haulagei When that point has been reached the_ stoops are taken out, working back to the shaft, and ; the 'whole mass above allowed to settle dowiji. This operation— viz., taking out ! the stooris, is'always a, dangerous , one, and often wher^ the rock overhead as soft or fi;iable f[ very difficult, it being no uncommon thing for hun- ( dred§ of stoops, representingthousands of tonsof coal to be left in,. and so lost from the impossibility, of keeping the strata above secured. The size of the stoops vary according to the thickness and nature of the seam, the \ position ana the angle' at which it lays, and.the nature of the strata overhead and' beneath.' The manager's Opinion on the subject .has something to do with it likewise, for I nave seen two Collieries alongside each other working ;same seam, , with ,the same conditions as to thickness, nature, angle*, roof, and pavement, and the stoops in the one case were 20 yards squared and in the other 12 to" 14 ' yards. In",Sp/ingfield it is a slight modification of ' this'- system that has .been adopted. ■ The stoops are of a considerable size, but we failed' to )( learn. their,, exact diinen-; sionsl The 'working | place's are ( , about',, 15 feet Vide.; and as -the roof is' v'ety treacherous a? large amount of timber is used, , Frpm the same .cause Idon^'think^all the stopps will ever be got out. ',' The workings fashe,st,to, the" 'rise stand now on a! big fault, about four, phains fr'omHhe dip workirigs°of the ,old .mine, now closed up and full- of water, and it' is not in'td'nddd to p'p'en 'up communigation with fit.; The men are' pai'dj a . .certain , pricq . per , ton to get' the coal, fill' it in' ike 'litfte .truck?,, and, take ; it to the bottom of the 'shaft', Jighti tramroads . being] laid into 'each working place ;f,or purppse' • • i

In ithe payment of the [miner* the present manager has introduced a Sliding scale; which seems; to give general , satisfaction, one miner we spoke to declaring that itisithei'fairest' schenje that could be adopted. The system isi this, j A. certain, rate per ton has been fixed; bblp.wj this the pripe.. never descends.' .Then the tHickness of- coal in each working' place. is measured once a week, and if it reaches a certain fixed standard .this price' is paid, and a penny extra per ton is allowed for, every inch it may be under it, no account being taken for anything over the standard thickness. • This certainly seems fair to liberality, always provided' that the standards are 'high enough ; but these we did not hear.

In the ventilation of the mine no special appliances are' used, the natural current being depended upon to a large extent. There'being no second outlet, 1 of course the one shaft must, perforce, serve the purpose of upcast and downcast, and.for this purpose is divided into two by a strong partition in the centre', the air current passing down one side, round the workings, and up the other. I must explain what is meant by the natural current for the' sake of those who are not miners. It is found, on going into the bowels of the earth, that the heat increases the farther you go down, and when workings are opened out and a_ number of men are 'at work, the heat increases still more, the air gets lighter and wants to rise to the level of air its own weight. But if all the air were to rise up out of the mine there would be a vacuum, and Nature won't allow this ; the cold air from the surface rushes down to fill the space vacated by the hot air, and if care be taken to keep a clear passage for each, so that they shall not mingle, there is a constant current passing round the workings, of course feebler in summer and stronger in winter ; because down below the temperature is always the same, no matter how it may vary on top, and if a very warm day came, so that the temperature at the surface was the same as down below, there could be no current; such is the natural current. There are several appliances used to aid the natural ventilation, the chief of which is a furnace, placed usually at the bottom "of the upcast, or a fan ' revolving rapidly,' sometimes placed at the mouth of the downcast to propel the air, more often placed at the top of tho upcast to draw it. Sometimes, but rarely, a jet of steam is introduced into the upcast, but this is not generally approved of, and is objectionable. Springfield having but one shafy, it is used for downcast and upcast, and the exhaust steam from the pump ascends the upcast, assisting tho ventilating current 'to a certain extent, and this is all the mechanical power used. This engine, was stopped for repairs while we went round the workings, which partly accounts for the bad state in which we found the air, ihe current being vory weak. Not having seon-the upper seam, F cannot speak authoritatively upon tho stateof tho ventilation there, but was informed that it was very had, much worse than tho lower scam, and' that was bad enough in all conscience. No fire-damp has been found in the workings, acircumstaiicepo.rhapstoberegietled, the health of the men employed in the mine is tho chief consideration, because wore there only a lifctlo of that dangerous paa present the v^ itiiatiou would to a certainty he. belter, and i thero would be less blaciv-damp gas, which is certainly moro deadly to breathe than ixvo.damp, and on the whole more dangerous^ in consequence of less attention being paid to it. (To be Continued,)