GYPSUM DEPOSITS OF NEW YORK 63 



New York can be penetrated without much trouble, as boulders are 

 usually scattered and of no great size. 



The extraction of gypsimi by open cutting is necessarily confined 

 to the eastern and central sections. The pocket deposits are worked 

 only in a small way after the simple methods of early days. More 

 systematic operations are carried on in connection with the rock 

 gypsum of Onondaga and Cayuga counties. The beds are exposed 

 along the sides of hills with a thickness of from 20 to 60 feet. The 

 quarries at Lyndon, Jamesville and Union Springs are opened on 

 such natural exposures. The overlying hmestones and drift are 

 stripped off or allowed to fall into the excavation left by the re- 

 moval of the g};'psuim. As the work advances into the hill an 

 increasing amount of overburden is encountered and in the course 

 of time becomes a serious problem necessitating a change to under- 

 ground mining or the abandonment of work altogether. There are 

 many abandoned quarries around Fayettevihe. At Union Springs 

 the drift covering is stripped by steam shovels, and the material 

 loaded on cars for removal to a dump. The breaking of the gyp- 

 sum rock is effected by driliing and blasting with black powder or 

 dynamite. Botli hand and power drills of the percussion type are 

 used in the quarries, the latter having perhaps less than the usual 

 advantage over handwork on account of the soft nature of the 

 material. 



In the western section the gypsum is mined underground, and 

 this practice has also been introduced recently in some of the quar- 

 ries around Fayettevillie to obviate the handling of the overburden. 

 Entrance to the workings is had through an adit where the g}'psum 

 approaches sufffciently near the surface, otherwise a vertical shaft 

 is used. 



The main adits which serve for Ihaulage are driven from 5 to 8 

 feet high and from 6 to 10 feet wide. The larger dimensions refer 

 to the mines near Jamesville, where the gypsum is excavated in 

 large rooms and removed by two-horse wagons that are loaded 

 directly at the working face. With thin beds the rock is hauled 

 out on mine cars attached to a cable. In some cases a foot or so of 

 the floor rock is removed to provide the necessary 'head room, but 

 this is generally unnecessary. The size of the rooms raui^^os up to 

 30 feet square. The overlying limestone makes a firm roof and 

 little support is needed in addition to that given by the pillars ; tim- 

 bering or backing is only rarely necessary. 



