64 NEW YORK STATE MUSEUM 



The mines at Akron and Oakfield, as well as those of the Con- 

 solidated Wheatland Co. at Wheatland and the Garbutt Gypsum 

 Co. at Garbutt are entered through vertical shafts from 50 to 70 

 feet deep. The shafts have either two or three compartments, one 

 of wlhich serves for a ladder and airway. The undergrounid work- 

 ings follow the room and pillar system but are more regularly 

 planned than those of the adit mdnes and are based on accurate, 

 surveys. The early methods of extending the drifts radiately from 

 the shaft or in a haphazard manner are -no longer pursiued to any 

 extent. The mines are often electrically lighted, ventilated by 

 forced draft and when necessary are drained by pumps wlhich raise 

 the water from a sump at the shaft bottom. Gas, electricity and 

 steam are' used for power purposes, tlhe fo-rmer being supplied from 

 the natural gas belt of west-ern New Yo^rk. Electric locotmotives 

 have been recently introduced for underground haulage, but in most 

 mines the cars are either pushed by hand or drawn by mules. The 

 hoisting is accomplished in various ways. At the Garbutt mine a 

 derrick and boom raise the rock which is loaded into a metal scoop. 

 The American G3^p5iim Co. has installed at Akron a bucket elevator. 

 Single and balanced platform hoists which raise the gypsum in the 

 mine cars are most generally employed. 



The rock is broken by drilling and blasting. Auger drills are 

 used in some mines and percussion drills in others, the former being 

 employed when the rock is suffioiently soft. With hard or tough 

 rock they are apt to become heated and to bind in the holes. Some 

 companies prefer to let the mining on contract, while others main- 

 tain the wage system. The miners represent all nationalities but 

 are mainly from southern Europe. A few Indians from the New 

 York reservations are employed. 



The mines are usually connected with the milling plants by 

 tracks. In the Fayetteville district, however, the rock is teamed, 

 except in one case where a traction engine is used to draw a 20-ton 

 wagon, and the haulage is here an important item of the woirking 

 costs. Much of the output of this section is shipped in lumps or 

 ground form to cement and plaster mills outside the district. 



ORIGIN OF GYPSUM 



General principles and theories 



Gypsum is formed by the combination of sulfuric acid with lime 

 in the presence of water. The sulfuric acid need niot necessarily be 

 in free state, since almost any soluble sulfate may react upon lime 



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