152 Journal of the Mitchell Society [March 



the limestone ore may be replaced by silicate ore such as was found 

 in the old Wauphbank opening above the present mine, in which case 

 it may be valuable or worthless, dependino- upon the width of the vein. 

 The limestone ore is merchantable even when its iron content is as low 

 as 35%. The silicate ore must carry much more iron l^efore it will be 

 accepted at the furnace, and most of it therefore must be concen- 

 trated. 



Urbana, III., July, 1921. 



