The usual whim employed in the mines is exhibited in the annexed cut:

Fig. 19.

A vertical axis supports a drum on which a rope is wound and unwound the rope passing over fixed pulleys, called poppet-heads, and being attached to the two kibbles or buckets, one of which descends as the other ascends. In raising the heavy masses of copper at the Cliff mine, a powerful capstan is used, in connexion with suitable tackle, by which a weight of several tons can be raised.

Having thus briefly noticed the general nature of the exploration, we will now proceed to describe the principal mines in this district; and to illustrate the method of working, and the progress of the under-ground operations, we have prepared several sections, taken principally from surveys and measurements of M: Hill.

CLIFF MINE.

The Cliff mine is situated on Keweenaw Point, about three miles from the lake shore, in the southwest quarter section 36, township 58 north, range 32 west. A range of elevated hills sweeps round in a crescent form, trending in a south westerly direction, and forming the western boundary of the valley of Eagle river. In places these hills attain an elevation of 500 feet, and towards the valley present bold mural escapments, while on the side exposed to the lake the slope is gradual. This range is composed of trappean rocks. The summit is capped by a hard crystalline greenstone, as at the Cliff mine, passing into a feldspathic porphyry, as at the Almon. Below, and forming the base of the ridge, is a belt of granular ap, oc casionally amygdaloidal. Between the two there is a thin belt of slaty chlorite about twelve feet in thickness. These belts dip to the north at no angle of 45°, conforming in this respect to the inclination of the dental Jocks which flank the range on the north. Wherever veins are observed in the greenstone, they are found to be pinched and barren; but where they enter the compact or granular trap they expand in width, and becone charged with metal. This trap has a good degree of firmness, and "consists of labrador feldspar, and chlorite. It has been reinarked that the best rock in this region for productive veins is neither a crystalline greenstone nor a soft porous amygdaloid, but a granular trap, with occasional amygdules scattered through it, and possessing a good degree of consistency. Where veins enter the greenstone, as before remarked, they become pinched; where they penetrate the soft amygdaloid, they beconie scattered and lose themselves.

The lode of the Cliff mine is seen to occupy a break or depression in the hill, and thence can be traced to its base. It was discovered in the summer of 1845, and during the succeeding fall a drift was carried into the greenstone about one hundred feet, (see plan, A,) and between that point and the summit several others were opened. When first discovered, the vein could only be seen in the upper belt of greenstone, the metalliferous zone being concealed by detritus. No one could have inferred from its appearance at that time that the enormous masses of copper existed but a short distance below which subsequent explorations revealed. It was examined by Dr. Jackson and Mr. Whitney conjointly, about the time of its discovery, who reported that the surface indications were not highly favorable at the points where the vein was exposed, but that, as it became wider and richer in its downward course, the company should by all means make a thorough examination by uncovering and examining the vein at the base of the cliff. At the summit it appeared hardly more than an inch or two in width: the gangue was mostly prehnite, with copper associated with silver, incrusted with beautiful capillary crystals of red oxide. Further down the vein was again exposed; here it had expanded to the width of nearly two feet, the veinstone consisting of a series of reticulations of laumonite.

Up to this period the sandstone and conglomerate were supposed by many to afford the best mining-ground, and that to this source they were to look for permanent supplies of the sulphurets of copper.

During the winter of 1845-46, some German miners, in clearing away the talus near the base of the cliff, discovered a small loose specimen of mass copper. This stimulated them in their researches, which resulted in the discovery of the vein in the belt of granular trap (b) about twelve feet to the east, showing that it had been subjected to that amount of heave or dislocation. From that point a level was carried into the hill seventy feet before anything valuable was developed, when the great mass, so called, was struck-a fortunate circumstance, not only to the company, but to the whole mining interest on Lake Superior. It gave encouragement to those engaged in these pursuits, and induced them to persevere. It also demonstrated the true source from which the loose masses occasionally found on the lake shore had been derived. It demolished the fanciful theory advanced by at least one geologist as to the transport of the Ontonagon mass from Isle Royale, and showed that it was not necessary to resort to icebergs and changes in the relative level of land and water to account satisfactorily for its position. From that time to the present day, hardly a month has elapsed without developing new masses; and their occurrence, so far from creating wonder, is regarded as a matter of course. The largest single mass hitherto exposed weighed about fifty tons. The position of the mass copper in the vein is indicated by the spaces between the dotted lines marked M, while the intervening spaces, marked S, afford stamp work.

1

It will be seen, by reference to the plan, that the levels 1, 2, and 3 have been extended northwardly into the greenstone before described, but in no instance has the vein been found after having pierced that rock. This arises probably from the lateral dislocation before referred to, the true position of the vein being twelve feet to the west. As a matter of curiosity even, it would be desirable to cross-cut to determine the extent of this fault, and the character of the vein where it enters the greenstone. It will,

without doubt, be found less metalliferous at that point than in the granu lar trap which contains the present workings.

The deepest shaft in this mine has been sunk 270 feet below the surface. The other two are little less in depth. The adit, which drains the mine to the depth of 100 feet below the first gallery, has been extended 750 feet. The amount of stopeing and timbering, and the disposition of the attle, or rubbish, will be seen by inspecting the plan.

The force employed in this mine at the present time consists of 160 men. The mine is under the management of Capt. Jennings, who has displayed much energy and judgment in developing it. If any criticism may be allowed, it would be to the effect that there has been no increase in the force for the last eighteen months. The openings in the mine should be in advance of the stope-work. By pushing these forward the country is explored, ample space is given to the miners to work, and op portunities from time to time afforded to increase the force.

The machinery employed for raising the ore and freeing the mine from water is admirably contrived; but the mine is now so thoroughly opened that the company will soon substitute a steam-engine in the place of horse-power. The stamps erected here were the first which operated successfully, and have served as a model for the mines in other parts of the district.

The connexion between the different parts of the mine is exhibited in Plate VIII, which is to be regarded as a plan, rather than a landscape. The cliff in the back ground consists of the crystalline greenstone before described. The vein traverses it in a nearly perpendicular direction, pierced by several galleries which extend no great distance, as will be seen by reference to the section, Plate VII-the vein here proving to be contracted and meagre in metal. The mining ground, represented in Plate VII occurs below the cliff of greenstone in a belt of amygdaloidal trap, and the relations of the two rocks are exhibited in the plan last referred to. The poppet-heads and whims for raising the ore and water are seen at the entrance of the shafts. The building near the centre is use1 for calcining the rock preparatory to stamping it, assorting the ore, and cutting the mass copper. The building on the extreme right contains the stamps and washing apparatus, which will be described in detail in another chapter. The productiveness of this vein may be inferred from the amount of stopeing which has been done, which is represented by the dark portions in the section, Plate VII. The disposition of the attle is also there represented.

From the reports of the trustees rendered in 1849 and 1850 we gather the following information:

The amount of capital stock paid in by the stockholders = $110,000. The personal effects of the company on the 1st of December, 1848, were $140,982, leaving a surplus of $111,105-a sum a little more than equivalent to the entire capital stock. This statement does not include the mine, with its fixtures and improvements, such as the stamping-mill, furnace, &c.

9

The net products of the mine, and the expenses of mining proper, from the commencement, are given below:

The

This embraces such expenses only as were incurred at the mine; those of insurance, commissions, freights, &c., are excluded. cost of transportation to Boston is $15 per ton; to Pittsburg, $7 50. The incidental expenses amount, to about 20 per cent., in addition to those of mining,

'The company have erected the necessary works at Pittsburg for smelt. ing and refining the copper, and they estimate that the shipments for the year ending December, 1849, will amount to 660 tons of refined copper. The product of silver for the year 1849 was $2,365 30.

The following table exhibits the monthly products of the mine for the two years ending December 1, and the character of the ore. It will be seen that, while the amount of the barrel and stamp-work has increased. the amount of mass copper has slightly diminished.