^^ IMAGE EVALUATION TEST TARGET (MT-S) % // A ,»* ■-^%^l^- c ^ f^. f/. 1^ 1.0 I.I 11.25 ■ 25 2.0 1.8 1.4 U o % > Sciences Corporation 23 WiST MAIN STREET WEBSTER, N.Y. 14580 (716) 872-4503 .v^x* .^ t/. . (meaning "CON- TINUED"), or the symbol V (meaning "END"), whichever applies. Un des symbolee suivants epparaftra suria dsrnlAre image de cheque microfiche, selon ie cas: Ie symb&Se — ► signlfie "A 8UIVRE", Ie symbole ▼ signlfie "FIN". Maps, plates, charts, etc., may be filmed at different reduction ratioe. Those too large to be i*ntlrely Included In one exposure are filmed beginning In the upper left hand corrver, left to right end top to bottom, as many frames as required. The following diagrams illustrate the method: Les cartes, planches, tableaux, etc.. peuvent Atre filmAs A d@e taux de rAduction diff Arents. Lorsque Ie document est trop gra;id pour Atre reproduit en un seul clichA. 11 est fllmA A partir de I'angle supArleur gauche, de gavnhe A droite. et de haut en bas, en prenant Ie nombre d'Images nAcessaire. Les diagrammes suivants illustrent la mAthode. 1 2 3 5 6 (4rt righia reserved.) ADVANCE PROOF-iSubjecttorevition.) This proof Is sent to you for discussion only, and on the express understanding that it Is not to be used for any other purpose whatever.— (£>eA>o 40. a/' the Ccnttiiuiion.) INCORPORATED M»7, TRANSACTIONS. K. B.— Tlil.1 Society, ns iv bwlr, does not hold Hii\t responaibli for the fact! and opinions Btated in any of ita publieationa. TJIE USE OF SAFE EXPLOSIVES IN MINES. I'AKT II. THB BESULT8 OP EXPERIMENTS. By E. Gilpin Jun., M. Can. Soo. C. E. To bo road on Friday, lllli Octoboi-, 1892. Tho question of tho use of explosives in tho provincial coal mines was forced on tho attention of tlio Nova Seotiu legislature by tho explosion at Springliill. Hero apparently no trouble had boon spared by tho Company to protect its workmen. Tho localily in which (ho xnlosion oiiginated was worked with safety lamps, the shuot, were fii'ed under tho diieclion of skilled men rtpoi-ially appointed for tho pui'pose, and then at long intor- val.-!, not lor loosening the coalj but to romovo a few inches of Btono in part of the roof. Copious watering was reiiorted to for laying the dust wliorevor the workings woie not naturally damp. In spite of those precautions it appeared upon a careful enquiry that a charge of gunpowder had partially done i's work, had flamed out, and tlie heat acting upon an atmosphere containing dust and gas gave rise to a very serious explosion. This showed that the mining practice of firing charges of gunpowder in plac38 where dust and gas could be present was dangerous in spite of tho precautious regaiding its use. After deliberation the Logi.-latuie enacted that when gas was found in any mine, in quantity sufficient to show in a safety lamp in three consecutive days, no explosive could bo used for two months. Provision was however made, that the Governor-in Counc'l could, upon the recommendation of a commission, including the Inspector and persons skilled in tho use and composition of explosives, that any explosive was safe, relax tho act in respect to explosives in favor of such safe explosive. In considering the practical application of the use of explosives in coal mines, the first point to bo settled is what constitutes a "gassy" mine, that is a inino in which the use of gunpowder becomes unsafe. The theoretical definition is that any mine in which gas is known to be given oil' may present it in volume sufficient to be ignited either alone or in connection with dust by the explosion of gunpowder. As a matter of fact small percent- ages are known by special tests to be present almost continuously in mines, although they cannot be detected by the best safety lamps in use. In all parts of the world in v^ell ventilated mines, gunpowder has been continuously used for years with impunity in tho presence of these minute percentages of gas. In such mines provided that they are damp, and free from dust, there is little danger even from excessive chaiges, or blown out shots of powder, so long as the ventilation is ml equate. Such mines when carefully managed and under proper discip- line gradually and by imperceptible degrees, pass, as they are worked at an iucroa,ied depth, into what may bo termed the Bocond stitgo, that of an increased ev-lutiou of gas, and usually of a greater degree of dryness. When this stage is reached a deficiency of ventilation in any district, coupled with dryjiess of the workifgs, produces a state of affairs higliiy dangerous in the event of flaming or blown ut shots. The th it'll slage Ih that of deep workings, which add to the dangew of incrousod exudation of ga?, and genural dustiness, those of extended fracture of the strata suddenly introducing volumes of gas directly into the workings oppressing it out of the old goaves. Under these con- ditions prudent management introduces safety lamps and abolished the use of gunpowder. The second stage is the most dangerous, as when the condition'* of safety and danger .are bal- anced, a tritling mishap pftvos the way for a disaster. Mining practice has so long sanctioned the use of open lights and high explosives in mines that have reached the second stage, that the reactio.i now setting in, in favor of their resti-iction, promises to seriously att'ect the economic exploitation of some coal beds. The Prussian Commission went so fur as to classify as "gassy," mines in which gas had been detected once in two years. It is therefore iipparont that in almost every di.itiict there are mines vai-ying in their degree of danger. Any hard and fast rule, for e.vamplo, precluding the use of high e.Kplo.iives when- ever gas is found, would not ntfect the mines of the third stage, but would greatly incrcaric the cost of the coal from the comp.xr- atively non-gaeeous mines. In the case of nianj' mines giving oif little gas, there are serious expenses, otT setting the cheapness with which the coal is mined, such as faults, steepness of dip, the presence of stone, weakness of the roof, etc. Su'ih mines would find it difficult to produce coal, if explosives were abol- ished. As it was apparent that a mine at any given time fairlv clas- sed as not " gassy" might in a few days on cutting a fault, giving off gas, or entering a disturbed section of coal, become decidedly "gassy" it was considered that the limitation imposed in the act would give a fair warning of danger arising in the usual conditions of mining. In the case of mines naturally damp, and decidedly free from gas, permission was also made in the act that any local and tcmporury detection of gas would not exclude the use of powder UMtil it became evident that the incroa-