THE MINING AND QUARRY INDUSTRY I9I4 39 



The furnace tests are the subject of a very complete report 1 by 

 F. E. Bachman, who as metallurgical expert and manager of the 

 company was present during the trial. It appears that the magne- 

 tites involved no special difficulties in treatment, at least when em- 

 ployed to the extent of one-third or one-fourth of the charge, and 

 therefore their use will not require any important modifications of 

 present methods or equipment. For the metallurgical details, on 

 which the conclusions here given are based, the report should be 

 consulted. 



The tests were made with concentrates prepared in a small experi- 

 mental mill at the mines and also at the commercial mills (Nos. i, 

 2 and 4) at Mineville. In none of the plants was the treatment 

 of the crude ore very successful, since the iron content was not 

 raised above 55 or 56 per cent, while the titanic acid averaged 

 around 12 or 13 per cent. The quality of the concentrates may be 

 considerably improved, when once the mill practice has been modi- 

 fied to meet the physical conditions of the ores which are not the 

 same as those characterizing the nontitaniferous class. Previous 

 experiments on a fairly. large scale indicate that the iron may be 

 brought up to about 60 per cent with a titanium content of 10 per 

 cent or less. 



In so far as the furnace tests are concerned, the results indicate 

 that the Lake Sanford magnetites are no more refractory than the 

 ordinary magnetites. The fuel consumption in the reduction of the 

 iron actually may be lower, although counterbalanced by the some- 

 what greater proportion of slag produced to the unit of iron. The 

 titaniferous slags are more fluid than those free of titanium, con- 

 trary to what has been commonly supposed, and there is less ten- 

 dency for the furnace to hang and slip when operated on a titani- 

 ferous charge. The quality of the iron is good, numerous tests indi- 

 cating that it is stronger than ordinary pig of the same silicon 

 content. It contains less sulphur and. the silicon is lower by an 

 amount corresponding to one-half of the titanium content. The 

 latter ordinarily does not exceed about one-half of 1 per cent. 

 The iron contains up to one-tenth of 1 per cent of vanadium. 



MILLSTONES 



Millstones are quarried from the Shawangunk grit of Ulster 

 county, one of the few sources of these materials in the United 

 States. The industry was established there many years ago, and 



1 Amer. Iron and Steel Inst., Oct. 1914. 



