﻿Segregation in Ores and Mattes. 177 



obiter dicta. To one familiar with the unique appearance 

 of the Sudbury ores, their immense size, their geological 

 and commercial importance would seem to warrant close 

 study, long-continued observation and experimental 

 research before a sound judgment as to their origin could 

 be reached. In order to furnish some material or basis on 

 which a judgment can be made, the following data 

 concerning the similarity of segregation in mattes and 

 ores are submitted. 



Copper nickel matte, made in water-jacketed blast- 

 furnaces from roasted copper-nickel ore, consists of a 

 mixture of sulphides of copper, nickel and iron. An 

 average matte will contain, approximately, 



Cu, 24 per cent. 



Ni, 20 " " 



Fe, 28 " " 



S, 28 " " 



This matte is tapped into hemispherical or conical cast- 

 iron matte pots or moulds, in which it is allowed to set, 

 after which it is turned out on the dump to cool. These 

 moulds or matte pots are about 24 inches diameter by 14 

 inches deep. After the matte has set, and while cooling 

 on the ground, it cracks by contraction, the cracks 

 extending either radially from the centre, splitting the 

 matte into pyramidal or cuneiform fragments, or else 

 vertically through the centre, dividing the matte into 

 quarter sections. On a pot of matte broken in the latter 

 shape, concentric iridescent bands of color show the rate 

 at which the matte has cooled from outside to centre. 

 The specific gravity of matte does not vary appreciably 

 throughout a pot, it being, as a rule, from 5 to 5.2. 



After matte has been broken, two separate forms of 

 incrustations may be observed on its surface. The first 

 consists of small hairs or wiry crystals of copper, often 

 occurring in small geodes or bubbles near the top or 



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