130 NEW YORK STATE MUSEUM 



The mill concentrates average : 



First grade 70 to 80 per cent carbon 



Second grade 60 to 70 per cent carbon 



Third grade 25 to 30 per cent carbon 



Fourth grade 8 to 12 per cent carbon 



They are bagged (a bag weighing about no pounds) and shipped 

 to the refining mill. 



A concrete example of milling practice. It was not possible for 

 the writer to secure data for a complete account of the milling 

 practice in the Adirondacks. The wet process of the Empire 

 Graphite Company, now the Flake Graphite Company, has, how- 

 ever, been clearly set forth by F. C. Nicholas. 1 The writer can 

 do no better than to abstract the article. 



The mill, which is arranged on the gravity principle, has a 

 capacity of 200 tons in 24 hours. 



The material from the mine is delivered to a rock breaker and 

 reduced to 1^2 to 3 inches in size. The broken rock then drops to 

 the rolls, which are 20 feet long by 2^ feet in diameter, which 

 reduce it to a fine sand. This is fed to a second pair of rolls more 

 closely set. The fine powder is then ready for the buddies. The 

 buddies are constructed of reenforced concrete and lined with 

 matched boards, 18 feet in diameter and 4 feet high. The concen- 

 trates from the first operation are sent to a second set of buddies. 

 A set of wet screens is next in order, where the graphite flake is 

 divided into two sizes. A rotary steam dryer then removes the 

 moisture. The final process makes use of silk cloth screens that 

 classify the flakes into four sizes. 



Since this was written, two banks of five stamps each, manu- 

 factured by the Allis-Chalmers Mfg. Co., and another set of buddies 

 have been installed. It is believed that the stamps have replaced 

 the rolls. Final treatment is accomplished in Hooper air jigs, manu- 

 factured by the Ticonderoga Machine Company. A classifier is 

 being constructed and will serve to recover some of the graphite in 

 the buddle tailings. A change in the type of the crusher is also 

 being made. 



Such changes in the equipment for the concentration of an ore 

 as are found here are evidence of the experimental state of graphite 

 milling. 



1 Min. World, Jan. 4, 191 8, p. 18 



