On Underground Temperatures. 



15 



Jane Pit, 

 Hetton Colliery. 



Circula- 

 tion 

 of air 



Dis- 

 tance 

 from 

 shaft. 



Temperature of 



Temperature (the 



mean annual 

 surface being 47°) 

 calculating 



Depth 

 below surface. 



per 

 minute. 



Intake 

 air. 



Coal. 



Return 

 air. 



Coal. 



J. lOI 



60 feet 

 of depth. 



1° £™» 

 J. ior 



50 feet 



of depth. 



feet. 

 1080 

 1270 

 1320 

 1360 



cub. ft. 

 41,800 

 41,580 

 30,030 

 28,000 



yds. 

 410 

 955 

 1247 

 1640 



58|° 

 59| 

 62 

 63 



65° 

 65 

 66| 

 67 



70i° 

 71 

 69| 

 70 



68° 

 73| 

 72 

 72| 



65° 

 68 

 69 

 70 



68i° 

 72| 

 73J 

 74| 



Average 1357a 



35,352 



1063 



60f 



65f 



m 



m 



671 



72i 



from shaft the temperature of coal was = 65° F. Mr. Bryham states 

 that the reduction of temperature effected in this pit by ventilation 

 amounts to from 15° to 20° F., or even more in a strong current. 



Other returns give the column of air circulating through the pits 

 at from 50 to 150 million cubic feet in the twenty-four hours, with a 

 gain of temperature of from 10° to 20° F., which shows how great the 

 abstraction of heat from large and well-ventilated coal-pits must be. 

 These effects are rendered very apparent by some tables put in by 

 Mr. Lindsay Wood, of which the following is an abstract : — 





Depth 

 below 

 surface. 



Distance 

 from 



downcast 

 shaft. 



Intake air, 

 cubic feet 



per 

 minute. 



Temper 



Intake 

 air. 



ature of 



Ketmrn 

 air. 





feet. 



yards. 





Fahr. 





Eppleton Colliery, Durham, 



1100 



312 



78,720 



61 -0° 



70° 



13th Oct., 1869. Mean sur- 



1450 



2925 



11,550 



69-0 





face temp. - 53° F. 



1395 



4130 



4,500 



72-0 







j) 



4410 





74-0 





The same pit off work, 23rd 



1100 



312 



52,200 



57-5 



69 



Oct., 1869. Surface temp. 



1395 



4130 



3,240 



71-5 





= 52° F. 











Monkwearmouth Colliery, 



1676 



80 



38,250 



56-5 



77 



25th Oct., 1869. Surface 



1646 



1430 



71,500 



63 





temp. = 45° F. 



1638 



2850 



5,000 



75-7 







1646 



3256 





81-2 





Murton Colliery — off ivorJc. 



1339 



410 



76,160 



54-0 



68 





1374 



4400 



1,600 



70-0 





Surface temp. = 50°. 













