USGS Professional Paper 144 p 63

PART 2. ORE DEPOSITS

     HISTORY

     That the existence of native copper in the Lake Superior district was known to early Indians and that copper was mined by them is shown by numerous ancient pits containing masses of native copper in various stages of removal, together with the crude stone tools used in mining, and by the implements made from copper that are found in the region. (See pl. 1.)

     The earliest visits to the district by white men were made about the middle of the seventeenth century. In 1672 two Jesuit priests published a map of Lake Superior, and from time to time the Jesuit missionaries and others brought accounts of copper found along its shores. The names of these early explorers - La Salle, Allouez, Mesnard, Marquette, and Du Luth have been preserved in the geographic nomenclature of the region.

     In 1771 Alexander Henry, an Englishman, began the first mining operations on the banks of Ontonagon River near the present Victoria mine, where a great boulder of copper had been found. This boulder attracted much attention and was eventually sent to Washington, where it is still on exhibition at the National Museum. This work was soon abandoned, however, for the country rock was the unproductive Jacobsville ("Eastern") sandstone, the boulder as it later appeared being a glacial erratic derived from lodes that crop out farther north.

     The Lake Superior copper industry had its real beginning in 1830, the year in which Dr. Douglass Houghton, Michigan's first State geologist, made his initial visit to the region. His report, published in 1841, aroused a general interest in the district. In 1844 the Federal Government began a land survey at the instance and under the direction of Doctor Houghton, which was combined with the geologic and topographic surveys he was then making for the State of Michigan. These surveys, though interrupted by the death of Doctor Houghton late in 1845, were pushed to rapid completion. and served both to increase interest in the district and to facilitate its early exploration and development. Mining permits were issued by the Federal Government, the first in 1844, but they were abolished in 1846, and all mining lands were placed on sale.

     The Pittsburgh & Boston Mining Co., organized in 1844, began operations at Copper Harbor, where a few tons of black oxide of copper was mined. In the following year it opened the first successful mine, the Cliff mine, on a cross fissure vein in the north end of the district; the first dividend was paid in 1849. The Minesota mine was opened on a strike fissure toward the southwest end of the district in 1849 and paid its first dividend in 1854, followed by the neighboring National mine with a dividend in 1861. The Central mine, operating on the Central fissure, northeast of the Cliff mine, made its first shipment in 1856 and began to pay dividends in 1864. These fissure mines were noted for the enormous pieces of "mass" copper encountered in them. Several of these masses were estimated to weigh about 500 tons each.

     The Pewabic and Quincy mines were the first successful mines on an amygdaloid lode. They were opened on the Pewabic amygdaloid, in the Portage Lake region, in the central part of the district, in 1856; both mines began paying dividends in 1862.

     The Isle Royale lode,¹ also in the Portage Lake region, had been opened as early as 1852 by the Isle Royale Mining Co., incorporated originally to mine on Isle Royale, in Lake Superior. Although worked intermittently by a number of companies, this lode yielded no dividends until 1913.

     The Atlantic lode was discovered in 1864 and explored by the South Pewabic Mining Co. Intensive development was begun by the Atlantic Mining Co. in 1872.

     The famous Calumet & Hecla conglomerate was opened in 1864, and the company paid its initial dividend in 1869. Ten years later the Kearsarge and Osceola lodes were opened.

     The Baltic lode was discovered in 1882 but remained unexplored until 15 years later. This was the last important lode to be opened.

     Most of the fissure deposits have long since ceased to be productive. Of the lode deposits, all that have been largely productive are still producing or may be expected to produce under favorable conditions, though some of the mines on the lodes have been worked out or consolidated with others.

NOTE

     1 The terms "lode" and "fissure deposit" are here applied in accordance with local usage. Strictly speaking, the "fissure deposits" are lodes, and the so-called "lodes" are not so, being rather in the nature of bed-replacement deposits. The latter, however, will consistently be called lodes in the present report; for the word is convenient and readily understood, and its use in this sense is perhaps not positively incorrect. As much can hardly be said of other applications of the term that are current in the district, where the word is used to designate (1) lava tops or conglomerates, or parts of them, which, though susceptible of mineralization, are not actually mineralized; (2) rock substance that has been mineralized; and (3) rock substance that is susceptible of mineralization. In general the use of the word in any of these senses will be avoided in this report, as being not only illogical but likely to cause confusion where the word is used in two or more senses in the same sentence.

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