﻿Segregation in Ores and Mattes. 



18^ 



of nickel more perfect on the lower levels than on the 

 upper. This is in reality the case. The nickel-bearing 

 portion of the Sndbury ores consists of magnetic pyrr- 

 hotite containing more or less intermixed pentlandite. 

 Mckel may be considered to exist in the pyrrhotite as 

 a foreign element, replacing a certain portion of the iron. 

 Pentlandite, on the other hand, is a true nickel mineral 

 (Fe + Ni), S, containing, approximately, Ni, 35 per cent.; 

 Fe, 30.25 ; S, 34.75. While it is true that the percentage 

 of nickel in the picked nickel ore does not vary much 

 with the depth, yet the deeper the mine the more perfect 

 will be the separation of nickel as a true nickel mineral. 



This nickel min- 



FiG. 7. 



eral does not oc- 

 cur in separate 

 massive form, but 

 as small crystals 

 or patches, vary- 

 ing in size from 

 that of a pin's 

 head to a hazel 

 nut, intimately 

 associated with 

 the pyrrhotite. 

 By crushing to a 

 rather coarse 

 powder and sort- 

 ing with a mag- 

 Ratio of nickel to copper in ores. Vertical line = copper \iq\j the minerals 

 taken as unity. Heavy line = ratio of nickel. Light line 



shows average variation of nickel ratio. Vertical distance CaU bc Separated 

 shows depth from surface. p t 



lor analysis. 

 In ore from near the surface the crystals of pyrrhotite 

 are small-grained, bright and sharply lustrous, containing 

 more than one-half of the total nickel as an element 

 replacing iron ; while in ore from a depth of several 

 hundred feet the pyrrhotite is largely in soft, dull crystals 





*w. . 



o\ 





\ 





\ 



\ 



Vertical central line of ores. 



