Copper From Lake Superior.--It would seem as if the period had at length arrived when we are about to receive substantial returns from the large sums of money expended on Lake Superior for the last two years. We learn form Col. Sheldon McKnight, of the Sault, who arrived yesterday, that the house of Tinker & Co., of which he is a member, have shpped on the schooner "Jone [sic]" now on her way down, 44 tons of native copper for the Boston and pittsburgh Company, consigned to Boston -- that there remains at his warehouse at the Sault, ready for shipment, 90 tons more of the same metal, which he will ship as soon as a vessel can get there. He also informs us that the Propeller has returned to Eagle River for about 70 tons more, which is on the Lake ready for shipment. This copper is in masses weighing from 500 to 3,500 lbs., and is of the very richest quality of native copper, and is worth, in Boston, $400 per ton. Thus the receipts of this company for the next 60 days will repay about $80,0000 of the expenditures.
From the mine we learn that they are raising immense masses of native copper, and that the great difficulty consists in cutting up the masses into small pieces to enable the shippes to get them on and off the vessels. One mass weighing 3,700 lbs. will be sent to England as a specimen of what Yankees can do in making copper.
From the north shore of Lake Huron, the propeller "Earl Cathcart" has taken on board 250 tons of grey and yellow sulphuret of copper, taken from teh Bruce mines, which is to be sent to Baltimore to be smelted. This mine is near St. Joseph's Island, with forty rods of the wharf, is 18 feet wide, and it is said that 500 tons per month of the ore can be shipped to market.--Det. Adv.