NEW SYSTEM OF TIMBERING MINES.

Te Aroha News, Volume VI, Issue 308, 17 October 1888, Page 2

NEW SYSTEM OF TIMBERING MINES.

TriE following new system of timbering, called the a square set," which is in operation in the Broken Hill Proprietary Company's mine, will doubtless be of interest to our readers. The old plan, which perhaps for ages has been used in most mines, consists, as is well-known to all miners, of a sole-plate with uprights of strong timber, generally in the round, slightly sloping inwards towards the top of the set, and a cap across, These sets are put in generally almost close to each other, and are backed by smaller timber placed longitudinally, which again, when required, are backed up by mullock or barren stuff, which in many cases has to be brought from the surface at a great expenditure of time and trouble, causing also considerable interuption to the taking out of the ore, all of which means in the aggregate a large money loss. The argument against the, old plan is very much stronger when applied to the working of a lode like that of the Broken Hill, which may be taken to average about 100 ft wide ; for with the old plan it would bo almost if not quite impossible to take out the centre mass of ore in such a big formation, as much of it would have to be left, as supporting pillars. The new system! of timbering consists of a succession of units, the unit being a square set of timber usually of 10 x lOin. These are put together in such a way that outside pressure only causes them to bind more tightly together. The squares are placed at intervals of 4ft from each other in the course of the drive, and stand at right angles to the walls of the lode. They are joined to (he next set by what is the same sort of square turned the other way about — that is, along the course of the lode parallel to the walls. All are tenoned and jointed in such a way that they form a complete set of cells in ev?ry direction you may choose to look, and constitute a homogeneous mass of squares. The width of the tnlckways is sft, and the height 6 or 7ft, as may be found convenient. The squares are put along the course of the lode so that any pressure that may come from the walls binds them more and more together. A floor of planking is put along the top of the sets when stoping 1 is being carried on above. One immense advantage of the system is that it can be extended in rleiinately in any wished direction, lpngthwise, laterally, or upwards. At one place I counted 10 square spts across the lode. In this way the ore can be worked out to the total width of the lode, leaving no pillars of ore and requiring no backing with mullock. When it is required to rise to a higher Wei, the sets are placed first in single tier above the others ; and as the ore is taken out the tiers can be extended in any or all directions. In this phase th?y somewhat resemble the stops of a staircase The appearance of a larsro level in the mine now gives one the appearance of being- in the 'tween docks of a very large ship. All is clean and npat. The ore when required to be sent down from ono level to another for the purpose of helna; trucked to the shafts is sent down shoot? right into the tiucks. The shoot*? fire so arranged that they can bp very easily removed when no longer wanted, and pat up elsewhere. The new system, in addition to being of much ci eater convenience in respect to erection, is said to be, considering the contingent s'xvinjrofbrinGTinsr in mullock to fill up with (as in the old), very considerably cheaper. The actual amount of timber used is less, atad no ore is lost or left in for supporting pillars. There is one point in which the new system occasions an extra con sumption of timber ; formerly chambers were scooped out when the roof stood croo<l without support, but now these vacant spaces have to be fully provided with the square sets the same as if they were still full of ore, in order to carry out the new system. It is easy to see that a lar^o quantity of timber is swallowed up in this way without any corresponding production of ore. But by the adoption of the new system, the ore faces are left constantly open and accessible through the entire opened portion of the lode, and any class cf ore that may be required for regulating the smelter charges, &c, can be taken out as and when required. Under the old sytem this openness of communication could not be maintained, as the mullock used for filling up blocked it. The advantages of the square set system are so obvious that, once seen, there can be no further doubt on the matter, and its adoption will tell very favourably on the futuro welfare of the Broken Hill Pvoprietary Company's mine. One advantage claimed for the new system must not be omitted, viz., accidents to the men are entirely avoided, or can only occur when the most ordinary precautions on their part are neglected. — Thames Star.

Professor Anderson, the well-known prestidigitator, who has been performing in Auckland with much success, announces that lie will give nn entertainment in the Te Aroha Public Hull on Saturday evening next The professor will introduce a number of awe inspiring and humorous novelties, and will be assisted by Mdele. De La Cour, the celebrated clairvoyante. Mirth and mystery will be characterestic throughout the performance, and Avill afford entertainment and* amusement for nil. The charges for admission will bo 3s and 2s, and children will be admitted half-price. Public notice is given by advertisement in another column that all persons are required on the 30th November next to fo'ward to the Property Tax Commissioner, Wellington, statements of all leal and personal pronorty belonging to them. Forms of statement will be delivered by the assessors where practicable, but if not received application must be made to the local assessor or at tho post'officc.