REPOET OF THE DIRECTOR AND STATE GEOLOGIST 1900 rl83 



used in the mill is hauled by teams from the other mine. About 

 15,000 tons of rock gypsum are shipped annually to plate glass 

 factories at Pittsburg. These factories calcine their own 

 gypsum and use the plaster of paris to embed the plate glass 

 while it is being polished. About 10,000 tons of plaster of paris 

 are produced annually. 



The equipment consists of one Blake crusher, one nipper, five 

 kettles and five mills. The nipper resembles an old-fashioned 

 coffee mill, to a certain extent. The upper part, however, con- 

 sists of a corrugated hopper in which a corrugated cone rotates^ 

 crushing the pieces of gypsum to about the size of a hickory nut. 

 The lower part breaks them up to about the size of peas. From 

 the nipper they are taken to the mills, and from the mills to the 

 calciner. Much trouble is experienced at the mines of this com- 

 pany, as well as the other mines in this locality, on account of 

 water in the winter time. Several of the mines must be pumped 

 or abandoned during the winter season. 



The gypsum is the whitest that is found in New York state. 

 It is said that about 80 feet below the first bed another bed of 

 gypsum is found about 10 feet thick, but this has not yet been 

 opened. 



The Oakfield plaster co. operates three mines, employing 

 about 15 men at the mines and eight at the mill. The equip- 

 ment of the mill consists of one Blake crusher, two burstone 

 mills, one bolter, and two kettles of 10 tons capacity. The daily 

 capacity is about 60 tons of calcined plaster. The annual prod- 

 uct is about 10,000 tons. The material is hoisted from the mines 

 of this company by horse power. 



The Genesee plaster co. of Oakfield has just completed a mill 

 which is not yet in operation. It has two mines having steam 

 hoists. The mill equipment consists of three calciners. None 

 of the Oakfield companies have used the Cummer process. The 

 kettle process is used by all. 



To the west of Oakfield, gypsum has been found near Indian 

 Falls, which is said to be darker than the material at Oakfield. 

 Xo commercial use has vet been made of this. 



