COMPOSITION OF THE COAL. 317 



( )n account of the thick parting above the bottom bench the coal is not 

 mined except in driving entries. The top coal consists of an upper layer 

 of 10 to 15 inches of dull and quite hard coal called "anthracite," but 

 carrying quarter-inch streakings of bright coal. Below itthe coal is mixed, 

 dull and bright, down to the uppermost parting. The second bench is 

 a bright bituminous coal and, like the bench below, is an excellent fuel 

 but carries balls of pyrite that cause much annoyance in mining and 

 prevent the use of the coal for many purposes. 



Samples representing the average quality of the different benches ©f 

 coal were collected and have been analyzed for me by Dr. Stokes, of the 

 chemical laboratory of the United States Geological Survey. The analy- 

 sis of the to}» coal shows — 



H,<> 3.66 



Volatile hydrocarbon 30.88 



Fixed carbon 55.50 



Ash 9.96 



100.00 



A sample of the coal from the middle of the seam shows a very large 

 amount of ash, and is evidently the cause of so much complaint that the 

 coal output is dirty. The analysis gave — 



11,0 2.68 



Volatile hydrocarbon 26.36 



Fixed carbon 44.01! 



Ash 20.04 



100.00 



A third sample, from the lower bench, shows a cleaner coal, low in ash 

 and higher in volatile combustible matter, possessing coking qualities 

 that lit it tor many uses for which the coals of the upper bench are not 

 available. This bottom coal should be economically mined and sepa- 

 rated with present methods of working. Under the present management 

 the Large amount of ash experienced in using this fuel must be charged 

 to the coal itself and not to dirt from the partings. 



An examination of the'seam as exposed throughout the workings shows 

 that the thin partings in the upper portion are quite variable in thick- 

 ness ami position and are occasionally wholly absent. Their maximum 

 thickness is about 2 inches. The lower parting is always present and 

 can be counted upon as to both position and thickness. As a rule the 

 roof is good, there being from 6 to is inches of slate over the coal. When 

 this slate is but 6 inches thick it is dill i cult to keep the roof up. but when 

 it reaches 18 inches the roof is perfectly sale. Throughout the mine the 

 roof rolls in gentle undulations. 



\ I.I I I ■ I'.i 1 1 . Okoi,. Soi . \ n„ V.'i . :',, 1891, 



