238 



There is no relation between time of year and low asli values. This 

 indicates that the variation in ash and heating value is due to variation 

 in the quality of the coal and not to any greater carelessness in mining 

 due to rush periods, since high ash tests do not coincide with winter 

 months. 



These determinations are presented on account of their value. They 

 represent actual coal and show exactly^ the kind of coal that can be de- 

 livered to customers. Many of the samples of coal which are furnished by 

 the mine operators for analysis are improperly taken and do not rep- 

 resent the average character of the coal. A small sample taken in a 

 mine will almost always show a better analysis than a sample taken 

 from a car. The official taking the sample leaves out the slate and takes 

 only the coal. The miner puts in the car as much slate as the boss will 

 allow. A black, shiny lump of coal, picked up at random and submitted 

 for analysis will show a higher grade than the dull, lusterless pieces. 

 A United .States bulletin advises mine officials to have analyses made of 

 samples taken from cars and warns them that analyses of samples taken 

 from mines will generally show a quality which cannot be reached in 

 car lots. For example, the analyses of coals "from nineteen of the lead- 

 ing mines of the State^ (Indiana)" show an average ash of 6.09 per cent. 

 The analysis of coal from the Summit Mine as given in the same report 

 shows 5.42 per cent, ash on the dry basis. No analysis in this laboratory 

 of samples of Indiana coal, which were known to be accurately taken from 

 cars, has shown such a low ash. Of course nut and slack coal is higher in 

 ash and lower in 15. T. U. than ruii-of-mine coal, but the difference be- 

 tween 11.64 and 6.09 in ash is greater than really exists between the 

 two grades of coal. 



It is of value to compare this Indiana coal with the coal i.urchased 

 by the United States under rigid tests and specifications during the year 

 J'JOS-9. The following table shows the analyses of bituminous coals which 

 were delivered under these specifications. The analyses of the coal pur- 

 chased by Indiana University are also iii.ju.l.-d in the table. 



» The rejected cars are inchuled in the averages. 



'31st Annual Report of Indiana Dcparlmont of (ieology and Natural Resource-, 

 pairc 21 (1906). 



