CHAPTER II 



QUARRY AND MILL OPERATION 



Quarry Operations. The problem of selecting a quarry 

 location is one attended by many chances of failure, and men 

 who have spent their lives in the stone business are likely to make 

 mistakes. The number of abandoned quarries in the district 

 indicates the mistakes made by stone men in the past. The 

 good building stone is not spread evenly over the stone belt as 

 has been supposed by many of the operators. The stone has 

 been laid down in large irregular lenses, and while a property 

 in operation may give a large quantity of very good stone, a 

 site only a short distance away may prove a complete failure. 

 One feature that may assist somewhat in the selection of the site 

 is the position of the quarry in the outcrop. The beds of rock 

 which carry the building stone slope gently to the west and south- 

 west so that in the eastern part of the stone belt the Oolitic beds 

 outcrop at the top of the hills and ridges. As these beds are 

 followed west or southwest they appear lower and lower down on 

 the hillsides and soon are covered by a layer of Mitchell limestone, 

 which is the next overlying member of the Mississippian rocks. 

 Still farther west the stone is found in the bottoms of the valleys 

 before it finally disappears under the overlying formations. 

 The rock in a quarry opening which is made where the stone is 

 near the tops of the hills and ridges will be found to be very much 

 seamed and weathered, and the amount of waste stone that must 

 he» rejected under such conditions often makes the quarry an 

 unprofitable venture. An example of this type of quarry is the 

 opening made just southeast of Bloomington, where there is 

 no protecting covering of overhdng rocks, and where the stone 

 is so seamed and weathered that the quarry has already been 

 abandoned. Where the quarry is opened near the bottom of the 

 valley the chance of obtaining a good grade and quantity of 

 stone is far better. 



The selection of a quarry site is determined by the amount of 

 stripping and by the quantity and quality of the stone encountered 

 in core drilling. The only method at present in use in the stone 

 belt for determining these facts concerning a quarry location is 

 vertical core drilling. This is accomplished by means of the 

 chilled shot core drill. This drill consists of a line of hollow rods 

 rotated by power thru a shaft and gearing, and fed forward either 



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