18 



UNIVERSITY OF COLORADO 



ORE BEDS. 



In order to analyze an ore bed, the chemist makes up a minia- 

 ture bed from the samples of the ores that formed that particular 

 bed. He is given such a list as follows: 



etc. 



The chemist has already analyzed these ores and still has the 

 samples. From these he now makes up the miniature bed, substi- 

 tuting grams for thousand pounds. Hence, on Summit No. 560, 

 above, he would weigh out 23.8 grams, and so on. Since the beds 

 average 1,000 tons, he will have a very large sample, which he will 

 mix thoroughly and quarter down to a sample of about £ pound. 

 From this he will make his analysis, saving the remainder of the 

 sample in case it is necessary to repeat the determinations. 



Where the bedding system is not carried out, the metallurgist 

 is kept pretty busy figuring his daily charges from the various lots 

 of ores received at the works. 



On all beds the following are determined : Total insoluble, true 

 silica, iron, manganese, lime, baryta and sulphur; sometimes zinc, 

 alumina, lead, copper, and other elements are called for. 



Silica, iron, manganese, lime, copper, and lead are determined 

 essentially as in ores and slags. 



Magnesium in Ores and Bed Mixtures. — Weigh 1 gram into a 

 No. 3 casserole and treat with a mixture of HN0 3 and HC1, using 

 sufficient nitric acid to completely oxidize the sulphides, and about 



*The smelter beds vary in size from one thousand tons to several thousand tons, and are 

 built up of the daily ore supplies that reach the works. This ore is spread out in 

 layers, so as to have as even a mixture as possible. When a given bed is about com- 

 pleted, it becomes necessary to determine its exact chemical composition, so that the 

 last layer can be added of ores of such nature as to bring the whole up to the definite 

 composition required for the smelter charges ; or the metallurgist can, if he so desires, 

 add the necessary ingredients to each charge. When this is done the furnaces are run 

 continuously on the given bed, receiving, of course, ore of uniform composition and 

 obtaining uniform metallurgical results. 



