Mance: Quarry Industry of Southern Indiana 11 



or azimuth of the seams, several seams would usually be crossed 

 by a single drilling. It would be well for the company interested 

 in a piece of land, with the idea of opening a quarry, to look more 

 fully into the possibilities of this form of drilling. Much valuable 

 data on cost of drilling furnished by Mr. Gunsolus of the DuPont 

 Powder Companj^ will be found in connection with the part of 

 this study devoted to the cement industry. 



After the location has been determined upon, there comes the 

 work of stripping and of levelling the floor. The disintegrated 

 material is removed in most cases by a stream of water, the 

 process being known as hydraulic stripping. The water is usually 

 driven by a large reciprocating pump, the most common in use 

 being manufactured by the Laidlaw Dunn Gordon Company or 

 the Worthington Company. The water is distributed to the 

 quarry in a 6-inch line, and this is reduced at the nozzle to a 

 1-inch or a IJ-inch stream. The nozzle is held in position on 

 a jack, and the operator controls the stream by means of levers 

 on the jack. The water is allowed to flow into a catch basin 

 where the material carried by the stream is deposited and the 

 water can be used over and over again. These reused waters 

 are usually heavily charged with fine material in suspension and 

 since they are never given time enough to settle, the material 

 must pass thru the pump many times. Under these conditions 

 the life of a reciprocating pump is very short, since the wear on 

 the cylinders is very rapid. In this respect the work could be 

 accomplished better by centrifugal pumps where the clearance 

 could be so adjusted as to handle water with any amount of dirt 

 in it, without excessive wear on the pump. Centrifugal pumps 

 are now constructed that will give any desired head, and since 

 their motion is well adapted to electric drive, they should soon 

 displace reciprocating pumps in quarry-stripping operations. 

 The securing of an adequate water supply for hydraulic stripping 

 is a serious problem in many of the quarries, and a catch basin 

 is used so that as little as possible of the water is lost. Most of 

 the work of stripping is done in the spring when the water supply 

 is relatively large. 



After the floor has been stripped of waste material the work 

 of leveling follows. This is often accomplished by- means of drill- 

 ing and wedging or drilling and blasting. In the former process 

 the holes are drilled by means of steam or compressed air drills 

 to a depth of about 8 inches, about a foot apart in the direction 

 in which it is desired to split the rock. In these holes steel 



