a trace of the other. It is evident from this that they cannot have been in a fused state in contact. The quantity of silver is small; the largest piece ever found weighing a little more than 8 lbs. troy. This was met with at the mines near the mouth of Eagle river, where a considerable number of loose pieces, together with loose masses of copper, were obtained in exploring deep under the bed of the stream an ancient deposit of rounded regular shape and projecting arms of copper, which often stretch forward, and up and down, connecting with other masses, it requires long and tedious mining operations to determine its dimensions. When it is supposed to be nearly freed along one side, very heavy charges of powder are introduced in the rock behind the mass, with the view of starting it from its bed. When cracks are produced by these, heavier charges are introduced in 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 its 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. of even the trap rocks themselves of this locality 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 particles are left behind. This is shovelled into small casks for shipment, and is known as stamp copper. The stamping and crushing machinery, such as have long been used at the mining establishments of other countries, were found to be entirely too slow for the requirements of these mines, and they have been replaced by new apparatus of American contrivance, which is far more efficient than any thing of the kind ever before applied to such operations. The stamps herctofore 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 1855 each stamp is to crush over one ton of hard 1858, hour. It falls trap rock a large 1860 every upon 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 stamp-head covers about one-fourth of the the year 1857 are as follows:— The principal mine of this district is the Cliff mine of the Pittsburg and Boston Company, opened in 1845, and steadily worked ever since. In 1858 the extent of the horizontal workings on the vein had amounted to 12,368 feet, besides 831 feet in cross-cuts. Five shafts had been sunk, one of which was 817 feet deep, 587 feet being below the adit level, and 230 feet being from this level to the summit of the ridge. The shaft of least depth was sunk 422 feet. 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 :Price per lb. Mineral Refined Yield deducting copper. per cent. cost of Ibs. smelting. 1,071,288 47.88 cts. 27.32 1,315,808 56.85 2,995,837 1,874,197 62.56 3,291,289 2,220,934 67.48 Year. produced. 1853, 1854, 1855, Value realized. $292,647 05 :4.38 820,783 01 25 33 475,911 26 24.12 535,848 67 1857, 8,363,557 2,563,850 70.28 20.44 497,870 47 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 size. On the eastern side of this lake are worked, among other mines, the Quincy, Pewabic, and Franklin, and on the opposite side the Isle Royale, Portage, and Columbian mines. The most successful of these has been the Pewabic. Operations were commenced here in 1855 upon an unimproved tract, requiring the construction of roads and buildings, clearing of land, etc. etc., all involving for several years a continued heavy outlay. The immediate and rapid production of the mine required the construction of costly mills, without which a large proportion of the copper would be unavailable for the market. The first three years the assessments were $50,000, and the shipments of barrel and mass copper were in 1856 973 tons; in 1857, 209, 328 tons; in 1858, 402 tons; in 1859, 81377 tons. The proceeds from the sales up to this time paid off all the expenditures, and left besides a considerable surplus. The Franklin Company, working the same lode upon the adjoining location, commenced operations in July, 1857, and that year shipped 20 tons of copper, the next year 110 tors, 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 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. The great mine of this district for fifteen years was the Minnesota, two miles east from the Ontonagon river. The explorers in this region in the winter of 1847-48, found parallel lines of trenches, extending along the trap hills, evidently made by man at some distant period. They were so well marked, as to be noticed even under a cover of three feet depth of snow. On examination they proved to be on the course of veins of copper, and the excavations were found to extend down into the solid rock, portions of which were sometimes left standing over the workings. When these pits were afterward explored, there were found in them large quantities of rude hammers, made of the hardest kind of greenstone, from the trap rocks of the neighborhood. These were of all sizes, ranging from four to forty pounds weight, and of the same general shape-one end being rounded off for the end of the hammer, and the other shaped like a wedge. Around the middle was a groove-the large hammers had two-evidently intended for securing the handle by 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 64 inches in length, the same in breadth, and 24 inches in thickness. 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. mit. 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 veins worked by the Minesota ComThe quantity of hammers found in these pany all lie along the southern slope of the old workings was so great that they were col-northern trap ridge, not far below the sumlected 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 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 among the copper has amounted in one year to about $1,000. of the pieces into which it was cut, but it is 384,394 1,626 71 515,786 120,000 ... 8 months to Sept. 1...... 1,431 1860, Estimate, for the year.. 2,250 In consequence of recent discoveries of masses of copper running into the sandstone off from the vein itself, the product of the year 1860 will considerably exceed that of any other year; the profits, however, are not proportionally large, owing to the low price of copper. To this the diminished profits of 1858 and 1859 are partly to be attributed. The product for 1857, 1858, and 1859 was divided as follows: Barrel work. Stamp work. lbs. lbs. Besides the dividends named, the original stockholders have derived large profits from the sale of portions of the extensive territory, three miles square, which belonged to the company, and the organization upon these tracts of new companies. Before the completion of the St. Mary's Canal, no exact records were preserved of the amount of copper sent from Lake Superior. But up to the close of navigation in 1854 it is supposed the total shipments from the commencement of mining in 1845 had been about 7642 tons of pure copper. Since that time, the annual product of rough copper has been as follows: 333,352 5,357 The condition of the Lake Superior mines at the close of the year 1860 is well presented in the business circular of Messrs. Dupee, Beck, & Sayles, of Boston, received since the preceding pages passed through the hands of the printer and stereotyper. From this we introduce the following additional matter. The depreciation in the price of copper from a maximum of 29 cents a pound of the few preceding years to a maximum of 24 cents and a minimum of 19 cents, had induced increased economy and care in the administration of the mines, the good effects of which were already beginning to be experienced : 6,094 5,896 6,041.0 8,543.4 "Freights to and from the mines from May to September were 25 per cent. less than in 1859. The transportation of a ton of copper from the lake shore to Boston, cost, after the opening of St. Mary's Canal, 1855, $20; in 1860, to Boston, $11, and to New York, $9. The substitution of bituminous coal for wood, which has been delivered during the past summer at the wharves of Portage Lake for $3.25 per ton, will save much money and leave the forests of the country for building materials and for timbering of the mines. With the wants of a rapidly increasing population, new and cheaper sources of supply are constantly amount brought down to Marquette, the port of shipment, in 1860, was: of iron ore from the Jackson Company, 62,980 tons; Cleveland Company, 47,889; Lake Superior Company, 39,394; total, 150,263. Of pig iron, Pioneer Company, 3050 tons; S. R. Gay, 1800; Northern Company, 650; total, 6500. Ore valued at $3; pig at $25; aggregate value, $588,289." The following statistics are presented of the principal mines :— COMPARATIVE TABLE OF SHIPMENTS OF ROUGH COPPER The weights of the barrels have been deducted, and the Central. opening in the region itself. Many agricul- Lake during the past season has been one of KEWEENAW DISTRICT. Copper Falls. Northwest... Pittsburg and Boston.. C. C. Douglass. Hancock. Mesnard. the greatest improvements in the navigation Adventure.. Bohemian. "In the Ontonagon district, a plank road has been completed recently, facilitating to a very great extent the transportation to and from the Minesota, National, Rockland, and Superior mines. "The iron interests of Lake Superior are rapidly attaining great importance. The Toltec.... Keweenaw District. |