40 MANUFACTURE OF FERTILIZING MATERIALS 



the material is broken by playing one or more 

 streams of water under a pressure of from 90 to 

 140 Ib. per sq.in. against the face of the deposit. 

 This operation causes the rock containing the 

 phosphate to crumble and flow into a ditch cut 

 in the underlying marl. The flow is aided at 

 times by additional water from a J-in. nozzle 

 ditch hose, the object being to drive the material 

 into a sump about 8 ft. square cut in the marl. 

 From the sump the material is lifted by an 8-in. 

 or 10-in. centrifugal pump and discharged into 

 the washers. Since the rock material consists of 

 firm sand and round phosphate pebbles, very 

 little of it being over 1 J in. in diameter, it is easily 

 made to flow through the ditch into the sump, on 

 a grade of 2 in. to the foot, by the use of about 

 ten times its weight of water. 



The hydraulic nozzles are connected to the main 

 water supply pipe which is usually 10 in. in diam- 

 eter. Where two nozzles are worked each has 

 from 200 to 500 ft. of 6-in diameter, flanged, 

 spiral-riveted, galvanized water pipe. Asphalt 

 roofing paper or tar board is used for flange gas- 

 kets. At one or two convenient places, in this 

 6-in. line, a ball-and-socket joint is applied to 

 facilitate the lateral movements of the nozzles. 



When two nozzles are used they are pointed so 

 as to wash the material to a central point, which 

 is the ditch leading to the sump. In case the 

 ditch clogs, an auxiliary hose is coupled just back 

 of the nozzles and the flow of water from this is 



