GEOLOGICAL SOCIETY OF PENNSYLVANIA. 



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feet; Rowlet's and some others extending towards the 

 Appomattox river. 



I am aware of the incomplete state of the details of 

 many important mines, and of divers omissions : but I 

 have not undertaken to describe all, or to particularize 

 more than I saw^, or derived from the best sources. 



The Bell and Rise shafts are now troubled with water, 

 chiefly arising from the fractured state of the superin- 

 cumbent strata, and the partial falling in of the galleries 

 in 1833. Mule power alone is employed to raise this 

 drainage water. An engine drains the water from the 

 Mid-Lothian mine. The Maidenhead mine is remarka- 

 bly dry. The sink or cistern at the bottom of the shaft 

 is only six feet deep, which suffices to collect all the 

 water during twenty-four hours, and is pumped out 

 every morning. 



Brown's mine is said to be wet, and to employ steam 

 power in pumping. 



The Black Heath mine has been on fire for some time, 

 causing a suspension of the works. 



Mills's Bell shaft, or rather some of the workings there, 

 have been on fire for twenty-five years, and it has now 

 advanced into some of the old workings of the Rise shaft 

 mine: but the works are still carried on, and communi- 

 cation with the fire is for the present stopped by walling. 



It is not known how this combustion originated — whe- 

 ther spontaneously, by decomposition of pyrites, or by 

 accidental causes. 



Fire damp does not now prevail in the Richmond mines 

 to an inconvenient extent. I could only hear of one tri- 

 fling accident that has occurred by this circumstance. 



Very little wood is employed in the working of these 

 mines, on account of the great thickness of the veins. 

 The w^eightof the roof is therefore necessarily to be sus- 

 tained by pillars, which in the Chesterfield mines vary 



