copper. This is metallic copper, precipitated from the waters of the mine by means of scrap iron thrown into the vats in which these waters are collected. The iron being taken up by the acids which hold the copper in solution, the latter is set free, and deposited in fine metallic powder. The ore is smelted in furnaces constructed on the German plan, and being put through twice, produce a regulus of 55 per cent. As soon as the proper furnaces and refineries can be constructed, it is intended to make ingot copper, and by working more of the mines belonging to the company it is expected the monthly production will soon be raised to 2,000 tons of 10 to 12 per cent. ore. crease in the supply of the metal will be derived from this source. The existence of native copper on the shores of Lake Superior, is noticed in the reports of the Jesuit missionaries of 1659 and 1666. Pieces of the metal 10 to 20 lbs. in weight were seen, which it is said the Indians reverenced as sacred; similar reports were brought by Father Dablou in 1670, and by Charlevoix in 1744. An attempt was made in 1771 by an Englishman, named Alexander Henry, to open a mine near the forks of the Ontonagon, on the bank of the river, where a large mass of the metal lay exposed. He had visited the region in 1763, and returned with a party prepared for more The two other companies have erected ex- thoroughly exploring its resources. They, tensive smelting works; and the mines of however, found no more copper besides the the Burra Burra are producing 450 to 500 loose mass, which they were unable to retons per month of 14 per cent. ore, and move. They then went over to the north those of the Polk County Company about shore of the lake, but met with no better 300 tons of 15 per cent. ore. Both com- success there. General Cass and Mr. H. R. panies will soon be able to make ingot cop- Schoolcraft visited the region in 1819, and per. The report of the Union Consolidated reported on the great mass upon the OntonCompany for the first year of their opera- agon. Major Long, also, in 1823, bore wit tions presents, against expenditures amount- ness to the occurrence of the metal along ing to $307,182.77, receipts of $457,803.73, the shores of the lake. The country, till leaving a profit of $150,620.96. A large the ratification of the treaty with the Chipportion of the regulus is shipped to England for sale. The profits of these mines were greatly reduced the first few years of their operation by the necessity of transporting the ores 40 miles to a railroad, and thence more than 1,000 miles by land and water to the northern smelting works. The establishment of furnaces at the mines not only reduces this source of loss, but renders the great body of poorer ores available, which they were not before. A railroad is now in process of construction to connect the mines with the Georgia railroads. West of the Alleghanies, the only copper mines, besides those of Lake Superior, are in the lead region of Wisconsin, Iowa, and Missouri. A considerable number of them have been worked to limited extent, and small blast furnaces have been in operation smelting the ores. These were found only near the surface, in the crevices that contained the lead ores; and in Missouri, in horizontal beds in the limestone, along the line of contact of the granite. The ores were mixed pyritous copper and carbonate, always in very limited quantity. The amount of copper produced has been unimportant, and it is not likely that any considerable in pewa Indians in 1842, was scarcely ever visited except by hunters and fur-traders, and was only accessible by a tedious voyage in canoes from Mackinaw. The fur companies discouraged, and could exclude from the territory, all explorers not going there under their auspices. Dr. Douglass Houghton, the state geologist of Michigan, in the territory of which these Indian lands were included, made the first scientific examination of the country in 1841, and his reports first drew public attention to its great resources in copper. His explorations were continued both under the state and general government until they were suddenly terminated with his life by the unfortunate swamping of his boat in the lake, near Eagle river, October 13, 1845. In 1844 adventurers from the eastern states began to pour into the country, and mining operations were commenced at various places near the shore, on Keweenaw Point. The companies took possession under permits from the general land office, in anticipation of the regular surveys, when the tracts could be properly designated for sale. Nearly one thousand tracts, of one mile square each, were selected-the greater part of them at random, and afterward explored and aban doned. In 1846 a geological survey of the region was authorized by Congress, which was commenced under Dr. C. T. Jacksop, and completed by Messrs. Foster and Whitney in 1850. At this time many mines were in full operation, and titles to them had been acquired at the government sales. and nowhere in quantities to justify the continuation of mining operations that were commenced upon them. The veins on Keweenaw Point cross the ridges nearly at right angles, penetrating almost vertically through the trap and the sandstones. Their productiveness is, for the most part, limited to cerThe copper region, as indicated by Dr. tain amygdaloidal belts of the trap, which Houghton, was found to be nearly limited to alternate with other unproductive beds of the range of trap hills, which are traced from gray compact trap, and the mining explorathe termination of Keweenaw Point toward tions follow the former down their slope of the south-west in a belt of not more than two 40°, more or less, toward the north. The miles in width, gradually receding from the thickness of the veins is very variable, and lake shore. The upper portion of the hills also their richness, even in the amygdaloid. is of trap rock, lying in beds which dip to- The copper is found interspersed in pieces ward the lake, and pass in this direction of all sizes through the quartz vein stones under others of sandstone, the outcrop of and among the calcareous spar, laumonite, which is along the northern flanks of the prehnite, and other minerals associated with hills. Isle Royale, near the north shore of the quartz. These being extracted, piles are the lake, is made up of similar formations, made of the poorer sorts, in which the metal which dip toward the south. These rocks is not sufficiently clear of stone for shipment, thus appear to form the basin in which the and these are roasted by firing the wood in portion of Lake Superior lying between is termixed through the heaps. By this procheld. The trap hills are traced from Kewee- ess the stone entangled among the copper naw Point in two or three parallel ridges of is more readily broken and removed. The 500 to 1,000 feet elevation, crossing Portage lumps that will go into barrels are called lake not far from the shore of Lake Superior, "barrel work," and are packed in this way and the Ontonagon river about 13 miles from for shipment. Larger ones, called "masses," its mouth. They thence reach further back some of which are huge, irregular-shaped into the country beyond Agogebic lake, full blocks of clean copper, are cut into pieces 120 miles from the north-eastern termina- that can be conveniently transported, as of tion. Another group of trap hills, known as one to three tons weight each. This is done the Porcupine mountains, comes out to the by means of a long chisel with a bit threelake shore some 20 miles above the mouth fourths of an inch wide, which is held by one of the Ontonagon, and this also contains man and struck in turns by two others with veins of copper, which have been little de- a hammer weighing 7 or 8 lbs. A groove is veloped until the explorations commenced thus cut across the narrowest part of the near Carp lake in these mountains in 1859. mass, turning out long chips of copper oneThese have resulted in a shipment of over 20 fourth of an inch thick, and with each suctons of rough copper in 1860, and give en- ceeding cut the groove is deepened to the couragement to this proving a copper-pro- same extent until it reaches through the mass. ducing district. The formations upon Isle The process is slow and tedious, a single cut Royale, which is within the boundary of the sometimes occupying the continual labor of United States, although they are similar to three men for as many weeks, or even longthose of the south shore, and contain copper er. This work is done in great part beveins upon which explorations were vigor- fore the masses can be got out of the ously prosecuted, have not proved of impor- mine. The masses are found in working the tance, and no mines are now worked there. vein, often occupying the whole space beThe productive mines are comprised in three tween the walls of trap rock, standing updistricts along the main range of the trap on their edges, and shut in as solidly as if hills. The first is on Keweenaw Point, the all were one material. To remove one of the second about Portage lake, and the third very large masses is a work of many months. near the Ontonagon river. All the veins It is first laid bare along one side by extendare remarkable for producing native copper ing the level or drift of the mine through alone, the only ores of the metal being the trap rock. The excavation is carried chiefly of vitreous copper found in a range high enough to expose its upper edge and of hills on the south side of Keweenaw Point, down to its lower line; but on account of ir regular shape and projecting arms of copper, a trace of the other. It is evident from this which often stretch forward, and up and down, that they cannot have been in a fused state connecting with other masses, it requires long in contact. The quantity of silver is small; and tedious mining operations to determine the largest piece ever found weighing a little its dimensions. When it is supposed to more than 8 lbs. troy. This was met with be nearly freed along one side, very heavy at the mines near the mouth of Eagle river, charges of powder are introduced in the rock where a considerable number of loose pieces, behind the mass, with the view of starting together with loose masses of copper, were it from its bed. When cracks are produced obtained in exploring deep under the bed of by these, heavier charges are introduced in the stream an ancient deposit of rounded the form of sand-blasts, and these are re-boulders of sandstone and trap. The veins peated until the mass is thrown partly over on of even the trap rocks themselves of this loits side as well as the space excavated will admit. In speaking further of the Minesota mine, the enormous sizes of some of the masses, and the amount of powder consumed in loosening them, will be more particularly noticed. cality exhibited so much silver that in the early operations of the mines a very high value was set upon them on this account. But at none of the Lake Superior mines has the silver collected paid the proprietors for the loss it has occasioned by distracting the attention of the miners, and leading them to seek for it with the purpose of appropriating it to their own use. Probably they have carried away much the greater part of this metal; at least until the stamp mills were in operation. To separate the finer particles of copper from the stones in which they are contained, these, after being roasted, are crushed under heavy stamps to the condition of fine sand, and this is then washed after the usual method of washing fine ores, until the earthy matters are removed and the metallic par- The principal mine of this district is the ticles are left behind. This is shovelled into Cliff mine of the Pittsburg and Boston Comsmall casks for shipment, and is known as pany, opened in 1845, and steadily worked ever stamp copper. The stamping and crushing since. In 1858 the extent of the horizontal machinery, such as have long been used at workings on the vein had amounted to the mining establishments of other countries, 12,368 feet, besides 831 feet in cross-cuts. were found to be entirely too slow for the Five shafts had been sunk, one of which was requirements of these mines, and they have 817 feet deep, 587 feet being below the adit been replaced by new apparatus of Amer-level, and 230 feet being from this level to the ican contrivance, which is far more efficient summit of the ridge. The shaft of least than any thing of the kind ever before ap-depth was sunk 422 feet. plied to such operations. The stamps heretofore in use have been of 100 lbs. to 300 lbs. weight, and at the California mines were first introduced of 800 lbs. to 1,000 lbs. weight. At Lake Superior they are in use on the plan of the steam hammer, weighing, with the rod or stamp-leg, 2,500 lbs. and making 90 to 100 strokes in a minute. The capacity of each stamp is to crush over one ton of hard trap rock every hour. It falls upon a large mortar that rests upon springs of vulcanized rubber, and the force of its fall is increased by the pressure of steam applied above the piston to throw it more suddenly down. The The quantities of the different sorts for stamp-head covers about one-fourth of the the year 1857 are as follows:face of the mortar, and with every succeeding stroke it moves to the adjoining quarter, covering the whole face in four strokes. The only other metal found with the copper is silver, and this does not occur as an alloy, but the two are as if welded together, and neither, when assayed, gives more than The production of the mine from the year 1853 is exhibited in the following table: Mineral Year produced. lbs. 2,268,182 2,832,614 Price per lb. Value realized. 1853, 1,071,288 smelting. 47.83 cts. 27.82 $292,647 05 1854, 1,815,808 56.85 :4.38 820,783 01 2,995,837 1,874, 197 62.56 25 33 475,911 26 3,291,239 1857, 1858, 1859, 1860 places copper occurs in masses scattered through the trap rock with no sign of a vein, not even a seam or crevice connecting one mass with another. They appear, however, to be ranged on the general course of the strata. At the Adventure mine they were so abundant, that it has been found profitable to collect them, and the cliffs of the trap rock present a curious appearance, studded over with numerous dark cavities in apparently inaccessible places leading into the solid face of the mountain. Cliff mine on the same range of hills. This region is of more recent development, the explorations having been attended with little success previous to 1854. The veins are here found productive in a gray variety of trap as well as the amygdaloidal, and instead of lying across the ridges, follow the same course with them, and dip in general with the slope of the strata. Some of the larger veins consist in great part of epidote, and the copper in these is much less dense than in the quartz veins, forming tangled masses which are rarely of any considerable The great mine of this district for fifteen size. On the eastern side of this lake are years was the Minnesota, two miles east from worked, among other mines, the Quincy, the Ontonagon river. The explorers in this Pewabic, and Franklin, and on the opposite region in the winter of 1847-48, found parside the Isle Royale, Portage, and Columbian allel lines of trenches, extending along the mines. The most successful of these has trap hills, evidently made by man at some been the Pewabic. Operations were com- distant period. They were so well markmenced here in 1855 upon an unimproved ed, as to be noticed even under a cover of tract, requiring the construction of roads and three feet depth of snow. On examination buildings, clearing of land, etc. etc., all in- they proved to be on the course of veins volving for several years a continued heavy of copper, and the excavations were found outlay. The immediate and rapid produc- to extend down into the solid rock, portion of the mine required the construction of tions of which were sometimes left standing costly mills, without which a large propor- over the workings. When these pits were tion of the copper would be unavailable for afterward explored, there were found in the market. The first three years the as- them large quantities of rude hammers, made sessments were $50,000, and the shipments of the hardest kind of greenstone, from the of barrel and mass copper were in 1856 trap rocks of the neighborhood. 97,856 2000 tons; in 1857, 209, 328 tons; in were of all sizes, ranging from four to forty 1858, 402 tons; in 1859, 813,7 tons. The pounds weight, and of the same géneral proceeds from the sales up to this time paid shape-one end being rounded off for the off all the expenditures, and left besides a end of the hammer, and the other shaped considerable surplus. The Franklin Com- like a wedge. Around the middle was a pany, working the same lode upon the ad-groove-the large hammers had two-evijoining location, commenced operations in dently intended for securing the handle by July, 1857, and that year shipped 20 tons 2000 of copper, the next year 110 tons, and in 1859, 218 tons; the total amount in capital furnished by assessments was $10,000. These two mines have been the most rapidly developed of any of the Lake Superior mines. The Ontonagon river crosses the trap hills about forty miles south-west from Portage lake, and the mines worked in the Ontonagon district are scattered along the hills north-east from the river for a distance of nearly twenty miles. The outlet for the greater number of them is by a road through the woods to the village at the mouth of the river. The veins of this district also lie along the course of the ridges, and dip with the trap rocks toward the lake. As they are worked, however, they are found occa STONE HAMMER. These sionally to cut across the strata, and neighbor- which they were wielded. In every instance ing veins to run into each other. In some the hammers were more or less broken, evi dently in service. One of them brought from the mine by the writer, and now in the collection of the Cooper Union of New York, is represented in the accompanying sketch. It measures 6 inches in length, the same in breadth, and 24 inches in thickness. The quantity of hammers found in these old workings was so great that they were collected by cart-loads. How they could have been made with such tools as the ancient miners had, is unaccountable, for the stone itself is the hardest material they could find. And it is not any more clear, how they applied such clumsy tools to excavating solid rock nearly as hard as the hammers themselves. Every hammer is broken on the edge, as if worn out in service. The only tools found besides these were a copper gad or wedge, a copper chisel with a socket head, and a wooden bowl. The great extent of the ancient mining operations indicates that the country must have been long occupied by an industrious people, possessed of more mechanical skill than the present race, of Indians. They must also have spread over the whole of the copper region, for similar evidences of their occupancy are found about all the copper mines, and even upon Isle Royale. It is not improbable that they belonged to the race of the mound builders of the western states, among the vestiges of whom, found in the mounds, various utensils of copper have been met with. But of the period when they lived, the copper mines afford no more evidence than the mounds. Some of the trenches at the Minesota mine, originally excavated to the depth of more than twenty-five feet, have since filled up with gravel and rubbish to within a few feet of the surface, a. work which in this region would seem to require centuries; and upon the surface of this material large trees are now standing, and stumps of much older ones are seen, that have long been rotting. In clearing out the pits a mass of copper was discovered, buried in the gravel nearly twenty feet below the surface, which the ancients had entirely separated from the vein. They had supported it upon blocks of wood, and, probably by means of fire and their hammers, had removed from it all the adhering stone and projecting points of copper. Under it were quantities of ashes and charred wood. The weight of the mass, after all their attempts to reduce it, appears to have been too great for them to raise; and when it was finally taken out in 1848, it was found to weigh over six tons. It was about ten feet long, three feet wide, and nearly two feet thick. Beneath this spot the vein afterward proved extremely rich, affording many masses of great size. The veins worked by the Minesota Company all lie along the southern slope of the northern trap ridge, not far below the summit. Three veins have been discovered which lie nearly parallel to each other. The lowest one is along the contact of the gray trap of the upper part of the hill and a stratum of conglomerate which underlies this. It dips with the slope of this rock toward the northnorth-west at an angle of about 46° with the horizon. The next upper vein outcropping, 80 or 90 feet further up the hill, dips about 61°, and falls into the lower vein along a very irregular line. Both veins are worked, and the greatest yield of the mine has been near their line of meeting. The position of the veins along the range of the rocks, instead of across them, gives to the mines of this character a great advantage, as their productiveness is not limited to the thickness of any one belt which proves favorable for the occurrence of the metal; and the outcrop of the vein can be traced a great distance along the surface, affording convenient opportunities for sinking directly upon it at any point. The Minnesota Company, having abundant room, were soon able to sink a large number of shafts along a line of outcrop of 1,800 feet, and several of the levels below extended considerably further than this entire length. In 1858 nine shafts were in operation, and ten levels were driven on the vein, the deepest at 536 feet down the slope. The ten fathom level at that time was 1,960 feet in length. This mine has been remarkable for the large size and great number of its masses. The largest one of these, taken out during the year 1857, after being uncovered along its side, refused to give way, though 1,450 pounds of powder had been exploded behind it in five successive sand-blasts. A charge of 625 pounds being then fired beneath it, the mass was so much loosened that by a succeeding blast of 750 pounds it was torn off from the masses with which it connected, and thrown over in one immense piece. It measured fortyfive feet in length, and its greatest thickness was over eight feet. Its weight was estimated at about 500 tons. What it proved to be is not certain, as no account was preserved |