REPORT OF DEPARTMENT OF METALLURGY. 255 



the vein to the foot-wall, taken from several levels, isolated specimens 

 showing the associates of the ore, several pieces of the copper, the chii)s 

 obtained in cutting- up the masses, and a largo and a small mass. This 

 collection includes 34 specimens. 



To represent the amygdaloid mines Mr. Kirby made a collection at the 

 Osceola Mine. On account of the more varied character of the amygda- 

 loid material this collection is much larger than the one from the Cen- 

 tral .'\line, but it is taken on the same general principle of representing 

 the vein by sections from the hanging wall across the vein to the foot 

 wall, and also in illustrating the changes of the material as one proceeds 

 down the mine. The collection includes about 80 specimens and is a 

 very complete illustration of the subject. 



To illustrate the extraction of the copper from the amygdaloid ore 

 Mr. Zukoski made a collection at the Osceola Mill. This includes the 

 average of the material sent to the mill, specimens of crushed material 

 as it passes the sieve, the headings from the mortars, and follows through 

 the process of concentration, showing the concentrated copper and the 

 waste products of each operation. 



To represent the conglomerate mines Mr. Kirby made a collection at 

 the Delaware Mine. This collection is taken on the same general plan 

 as the others, and also includes a section of 631 feet along the vein^ 

 showing the various changes that take place in the material. He also 

 collected a full series representing the concentration of the copper. 

 This collection includes 100 specimens. 



These three collections together represent in a very full manner the 

 interesting occurrence of free copper in the Lake Superior region, and 

 will be an exceedingly valuable addition to that subject. 



It was very unfortunate that the process of refining this material 

 could not have been followed out on the spot, but the proprietors of the 

 refining works at Hancock would not permit any systematic collections 

 to be taken. The only collections taken there were a short series col- 

 lected by Messrs. Kirby and Zukoski illustrating the smelting of the 

 slags obtained in refining the native copper in a McKenzie cupola at 

 the Lake Superior Native Copper Works. 



The process of refining the material from the Mass Mine is fully illus- 

 trated by a collection from the C. G. Hussey Works at Pittsburgh, Pa. 

 This collection includes the various grades of material received from the 

 concentrating works, a sample of the metal taken from the bath just 

 after the first skimming of slag, a sample taken just before beginning- 

 to rabble, a sample after rabbling, a sample just before poling, and a 

 sample of the refined metal, together with four skimmings of slag. To 

 these are added samples of the coal and charcoal used, of the sand for 

 making the bottom of the furnace, a piece of the pole used in refining, 

 and a test ingot showing the tests applied to the metal just before be- 

 ginning to cast. This collection was made by Mr. W. H. Johns. 



