

IN THE NICTAUX IRON FIELD WEATHERBE. 353 



The "calyx," or as it has been aptly termed the "chip 

 barrel," is also a tube of the same diameter as the core-barrel, 

 and surrounds the lower drill lod. ]t rests on the reducing plug, 

 and is open at the upper end. Water being fed down the drill 

 rods, passes out at the bottom of the hole, and is forced up 

 between the rock wall and the core-barrel and calyx. 

 This water naturally carries with it the sand and rock chips 

 formed during the process of cutting the core, until when the 

 top of the calyx is reached, the pressure is lessened by the space 

 being increased, and the chips fall into the calyx, thus forming 

 a perfect, though inverted record of the formation passed 

 through. To the top of the pulley-head is screwed the feed pipe, 

 and to the bottom a square rotating rod which is screwed to the 

 highest drill rod, and fitting through the rotating device is held 

 by a clutch, and thus the motion is given to the drill. 



Method of Operation. 



After setting up the drill, the first operatiou is to insert the 

 pipe-casing an iron tube slightly larger in diameter than the 

 outside of the core-barrel through the loose surface material, 

 and a short distance into the bed rock. 



This is done by placing on top of the pipe-casing a wooden 

 block (about 12" thick), and using a pounder worked with the 

 hoisting gear. A heavy, flanged iron pipe, weighing probably 

 400 Ibs. has been used for this purpose with success. Great 

 care must be taken to keep the piping plumb, as mistakes at this 

 stage will probably necessitate abandoning the hole. 



Another error that is sometimes made, and which by experi- 

 ence has been corrected here, is the digging of a shaft in which 

 to sink the casing. Even with the greatest care being exercised, 

 it is found that though the shaft outside the pipe may be filled 

 and thoroughly tamped, there is great liability of the hole being 

 blocked, and of the top of the calyx catching on withdrawal of 

 the drill. 



Having successfully placed in position the casing, the cutter, 

 and core-barrel, or if the rock is very hard, the shot bit is intro- 



