1866.] MACPARLANE — ON CUPRIFEROUS BEDS. 15 



are to be found within say five miles of the towns of Hancock and 

 Houghton on Portage Lake. Even the professional visitor, who 

 has given previous attention to the subject, cannot but be astonished 

 as he rounds the point beneath these towns, and sails up to them, 

 at the scene of life and activity which suddenly opens up before 

 him. Having only spent ten days in the district, it would be im- 

 possible for me to attempt to describe with a moderate degree of 

 minuteness even its principal mines. There are at least twelve mines 

 in operation within a short distance of the lake, and of these the 

 majority are producing copper in quantity varying from 20 to 120 

 tons of the pure metal monthly. The mines which have the lar- 

 gest production are those of the Pewabic lode, and it will be suffi- 

 cient to refer briefly to their mining and dressing operations. 



In exploring the cupriferous bed in the Quincy mine, as in fol- 

 lowing the other beds in the district, the miner has only its litholo- 

 gical character to guide him, there being no distinct joints or 

 walls on either side. The shafts, levels and winzes of the mine 

 are all opened within the bed so that the amount of dead loork done 

 is the very least possible. At the 100-fathom level the strike is N. 

 30° E., and the dip 70° north-westward. The shafts on the Quincy 

 mine are from 200 to 300 feet apart, and the levels from 72 to 75 

 feet beneath each other on the incline of the bed, and 60 

 feet perpendicularly. The width of the bed is from 6 to 30 

 feet and the average thickness ten feet. According to the 

 general experience at the mine, the thicker the bed the richer 

 is the rock in copper. About two-thirds of the area of the bed 

 is removed as remunerative ; the other third, although it may 

 contain some copper, is left standing, as unworthy of excava- 

 tion. The amount of ingot copper yielded by the ground actually 

 removed in 1864 was 562 lbs. per cubic fathom. Assuming the 

 sp. gr. of the rock of the lode to be 2.7, it thus yielded 1.4 per 

 cent. Of course the copper was unequally distributed through 

 the bed rock, and the true per centage would be at many places 

 above, and at others below that just mentioned. The bed is exca- 

 vated by a very judicious combination of over-hand and under-hand 

 stopping. The rock is removed to the shafts in waggons containing 

 about one ton each, and hoisted in skips or waggons of a peculiar 

 shape, running on tracks in the inclined shafts. The contrivance 

 whereby these skips are emptied on their reaching the surface is 

 without doubt the simplest and most beautiful anywhere in use. 

 There are six shafts ; the deepest, No. 4, is 660 feet vertically, 



