Report of Board appointed to inquire into the prevalence and prevention of lead poisoning at the Broken Hill silver-lead mines to the Honourable the Minister for Mines and Agriculture.

  • New South Wales. Legislative Council.
Date:
1893
Catalogue details

Licence: Public Domain Mark

Credit: Report of Board appointed to inquire into the prevalence and prevention of lead poisoning at the Broken Hill silver-lead mines to the Honourable the Minister for Mines and Agriculture. Source: Wellcome Collection.

Provider: This material has been provided by London School of Hygiene & Tropical Medicine Library & Archives Service. The original may be consulted at London School of Hygiene & Tropical Medicine Library & Archives Service.

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    purposes of ventilation only, the Letter is the ventilation of the main galleries ; but in every roine any recess carried olf a well-ventilated passage must of necessity become less and less well ventilated until it has been carried far enough to open into another well-ventilated passage, or in the case of stopes, until they have been raised high enough to open into a level above that from which they started. The ore is broken by blasting, or sometimes' with the pick, according to its character, and thus great quantities of dust are raised which settle upon the timbers, and which are raised again and again by every fresh concussion. In addition to dust, the air becomes mixed with carbonic acid from the earth itself, from candles which are burnt for light, from human respiration, and from combustion of explosives; and the fumes of dynamite form a serious impurity of another kind. The character of the dust, the extent to which it is sometimes present in the air of the stopes, and an idea of one way by which it enters the stomach from this source, may be gathered from the quotation already made at page 18 from Appendix L; in which latter, also, a note is made of the warm and oppressive feeling of the air met with in some of the less well-ventilated stopes and passages. This matter of ventilation is one of great importance, both in general and as regards presence in confined air, not only of lead-dust, but also of dynamite fumes. Natural forces are relied upon to ventilate metalliferous mines, and as regards main galleries are here sufficient; however, they must be supplemented in the recesses just referred to, and generally by forced currents of air. Now, in the first place, it seems necessary to furnish the Mining Inspector with a criterion of good ventilation, and not leave it, as at present it is left, entirely to his judgment, which practically means to his personal sensations—in this matter misleading, and therefore worse than useless. We have concluded that in such mines as these, where the main galleries furnish a nearly normal atmosphere, and the earth but little carbon dioxide, a criterion may be found in the proportion of carbon dioxide present, and that where the proportion exceeds one part in 1,000 parts of air the Inspector should have power to order work to cease in that place until, either by putting in a blower or by some other means, the proportion shall have been reduced to less than one part per 1,000 parts of air. Then as regards the laying of dust and dispersion of dynamite fumes, we draw attention to the following matters : —Water is at present led (in carefully managed mines) so that it can be scattered over lead faces, and it is usually run from an ordinary rubber hose; secondly, the fans by which the forced ventilation just declared necessary is best effected are most conveniently and most economically worked by air compressed at the surface and conducted below in pipes. Then, what is wanted to lay dust is not the slop of w^ater which issues from a hose, but a fine spray which shall damp without wetting ; and such a spray if properly produced would have the farther effect of washing the air as it passed through it, and so of clearing it of suspended dust particles. To produce this spray why should the compressed air not be turned into the water-pipe ? But it is especially desirable to kill the dynamite fumes, and for this purpose it would be easy to devise a spray- apparatus which should be worked from the compressed-air pipe, and which should be fed with a solution of proto-sulpliate of iron. Thus the three main objects might be gained at one operation, and gained quickly; the dynamite fumes would be killed, the dust would bo washed out of the air, the face and dis- lodged fragments would be damped, while no superfluous water would drip through the floors, &c., &c.; and there cannot be doubt that so far from its being costly to secure these advantages to the workmen it would prove profitable—by actual saving of time after shooting, and, less directly, by the improvement in w^orking power and energy which attends upon a pure atmosphere when it is substituted for a foul one. 16. The dangers due to dust (aggravated in the stopes underground by the other causes of ill-health which attend on faulty ventilation), are continued at the surface, in as far as ore is there handled after being raised, although in a minor degree, no doubt. Other and fresh dangers arc now added, however— they are those which attach to the operation of smelting. The way in which this part of the business is conducted is the following:—The smelting furnaces are structures which have an area of 47 square feet, and which are 14 feet high ; they are fed at the top; a for(!ed draught is supplied to them at a pressure of about 8 ounces; they stand in a row, and parallel with them runs the (champion) flue which leads