fwm "Fire-damp in Minds* 9 



they should be hung at about two- thirds of their length 

 froni their bottom end, and counterbalanced so as to act 

 against the current of air. In mines where horses are used, 

 a man will thrust them open without delay, and they will 

 immediately shut after him. Common doors, such as shut 

 one way, are on many accounts the best ; but they arc apt 

 to be left open in situations where persons, arc not expressly 

 appointed to attend them, and indeed bk)wn open by the 

 air acting in a contrary direction, owing to the suddeii im- 

 pulses of blasts, or'shots fired, &c. &c. 



Lastly, Great care ought to be taken to preserve the 

 air-ways, &c. in good repair; aud should any part of 

 them give way, no time must be lost in securinj:^ ihem, 

 and removing the rubbish, that there be no obstruction to 

 free ventilation *. 



When all the headings are completed, or as many of 

 them as are deemed necessary, it is customary to proceed 

 in working the mine; but, for reasons already staled, it 

 would be departing from my original intention to say any- 

 thing upon this head* 



Indeed, to an intelligent miner, who has an abundant 

 supply of air at his back, little difficulty will arise in turn- 

 ing it effectually to his purpose. 



Ventilating the waste or old ivorJdngs, so as to prevent 

 an accumulation of damp, is a matter of importance. In 

 thin mines it is not necessary to do it for any lenoih of 

 time, as the roof and Jloor soon gradually close together : 

 in others, where the roof\s rock, and of such thickness as 

 to stand under any circumstances, it may be practised with 

 case : it is in mines of four feet thick and upwards, whose 

 superior strata are not capable of supporting themselves for 

 a considerable width, that tlie greatest difficulties arise. To 

 leave sufficient pillars of coal would frequently be to bury 

 the profits of a colliery, and at the same time destroy an 

 amazing quantity of valuable fuel. 



Thin pillars are in general recpiired to ventilate the 

 workings, and these are for the most part left: where they 

 happen to stand until a general weight or settlement of the 



* I have known instances, where the air-ways have been so much ncg-- 

 lectcd in this particular, as to put a complete stop to the circulation of air; 

 and, as niig-ht very uati; rally be expected, sevecal niisfortu.nos happened ui 

 consequence. ''I'he ill eflbcts attending such unpardonable inattention ar,? 

 almost incalculable : — loss of men's lives, loss of time, exfiense incurred in 

 re^iairs rendered more difficult to accompti'ih from damages sustained by 

 expli>iionE; the invariable advanie in men's wages, as some compensation 

 lor the great dangers to which thty are exposed, may all be placed to this 

 account, 



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