EARLY IRON MINING

The Onset of Mining.
    To determine the land boundaries that would properly establish mining locations, it was necessary that a linear survey be made by federal authorities. Such a survey party, headed by US surveyor William Austin Burt, discovered the first iron ore deposit of the Lake Superior region-near present-day Negaunee, Michigan. The survey party had stumbled into the heart of one of the richest iron ore districts in the world.   On September 19, 1844, near Marquette County’s Teal Lake, William Austin Burt and his survey crew watched as the needle of their compass fluctuated wildly.  Burt had no idea that this accidental discovery would provide the foundation for America’s Industrial Revolution when he called out....."Boys, look around and see what you can find."
    On the heels of the surveyors came the government geologists. The iron formation in the Marquette Iron District commonly consisted of thin layers of silica-rich rock, such as slate or chert, alternating with thin layers of almost pure iron minerals-mainly magnetite, specularite and hematite-"whose purity and magnitude are unrivaled." Foster and Whitney’s geological map showed iron formations occurring in a belt eight miles across at its widest and extending west for some thirty miles to Lake Michigamme. Here a branch extended southward eight miles along the Michigamme River.
    The prospectors and miners followed the government geologists. The first iron mines in the Marquette District were in Negaunee and Ishpeming. Initially, only the near-surface concentrations of magnetic hard ore were discovered and extracted. The early mines were relatively small, shallow open pits (below), which often were soon exhausted. By 1875 some of the near-surface ore bodies were being followed underground. Early mining operations were carried on primarily by manual labor. After drills and hammers created holes for blasting, the blasted ore was then loaded into wagons that were hauled by mule or horse to the railroad.

    Development of the district began slowly but was hastened by the opening of the Soo Locks in 1855 and the building of railroads from Lake Superior to the mines during the late 1850s. Other key factors in the development of the district were the rapid expansion of New England manufacturing plants and the increased demands for iron caused by the Civil War. As a result of this need for iron, the entire Marquette District was eagerly explored with test pits. The number of new mines proliferated. By 1873 annual iron ore production from the Marquette District reached 1,000,000 tons.

    Some 60 km south of the Marquette District were the three segments of the Menominee District, the second great iron-producing area to be discovered in the Upper Peninsula. But development of the district was impeded by the lack of cheap transportation. Only when a rail line was built in 1877 to carry the ore from the mines to Lake Michigan docks could the ore in this area be mined profitably.
    Throughout the early phase of production, the ore was smelted on the mine site, using charcoal from local hardwoods, and then shipped via the Great Lakes. The needs of the smelting operation, combined with the activity of the lumbermen, succeeded in stripping the Upper Peninsula of most of its timber. It was perhaps fortunate, then, that during the 1870s, the center of the iron and steel industry moved to the markets, smelters, and coalfields of the Ohio Valley.
    During the 1870s high-grade ore was so abundant and mining and furnace methods were so crude that only the hard specularite and magnetite ores, mined in the Marquette District, were considered valuable. The soft hematite, which later came to comprise the bulk of the ore shipped from the Lake Superior area, was contemptuously called Lake Superior mud. By 1874, with the employment of more sophisticated smelting procedures, some furnace operators began using the more abundant, soft hematite ores.
    Transportation of the ore to Lake Michigan shipping docks, closer to the blast furnaces of Gary and Chicago, also proved difficult. Only when a rail line was built in 1877 to carry the ore to the Great Lakes shipping docks could the ore be mined profitably.
    At the west end of the Upper Peninsula lies the Gogebic District, the third great iron ore region to be discovered in Michigan. Here again, a lack of transportation and the general disdain for the soft hematite ores delayed the development of the Gogebic District into an ore-producing area until 1884.

Source: Unknown

Finding the ore.
    When prospecting for iron ore, attention was first paid to outcropping rocks to determine whether a region contained the iron formation. Once in proximity to the iron formation, the prospector looked for an outcropping of ore, or for signs that ore might be nearby, such as the presence of a boulder containing ore, a red, hematite-rich soil in the roots of a fallen tree, or the deflection of the compass needle by local magnetic attraction. Because bedrock is often buried, the prospector habitually examined the banks and beds of streams and the cavities under overturned trees for bedrock exposures.
    When an iron ore deposit was found, careful work was necessary to determine the quantity of ore present (defined by the deposit’s length, width and thickness) and its richness. The majority of mining-company failures occurred because their iron ore deposits were not rich enough to be mined profitably. A lesser number of failures happened because the ore deposit was too small, even though the ore was high quality.
    Only those parts of the iron formation where some natural process had concentrated the iron ore to at least 50% of the total rock to be removed could be mined at a profit. About 6% of the iron-formation area met this requirement. These rich, natural concentrates, called direct-shipping ores, were considered the only profitable ores until the 1950s.
    To determine an ore deposit’s boundaries, the area was first roughly mapped, noting all outcrops, then traversed with a dip needle to trace the deposit’s underground outline. The dip needle is a hand-sized, circular box with a glass top and bottom that allows the needle movements to be easily seen. The needle is counterpoised, resting horizontally when there is no local attraction but dipping in a vertical plane when attracted. The direction in which the dip needle points is due to the combined magnetic effect from both the earth and the local ore deposit. Since magnetic ore attracts the needle at the same distance with equal strength whether covered by rock, earth, air or water, this instrument was of great service to prospectors. The dip needle was successful in locating and tracing the boundaries of iron ore deposits because most iron ore was magnetic enough to produce an appreciable deflection in an ordinary compass bearing.
    The intensity of a local attraction depended upon the amount of magnetite in the rock and was measured by the number of needle vibrations in a unit of time. While a dip or defection was frequent, it usually did not signify a profitable iron ore deposit since there were many more lean ores than rich ones.

    The first iron ores usually discovered were hard magnetite and specularite. These dense ores were more readily found because of their resistance to erosion, their tendency to form outcrops and their ability to magnetically deflect compass needles. However, most of the ore mined in the Michigan districts has been the soft hematite ores. Although more abundant, this earthy ore was more susceptible to erosion and tended to recede into the subsurface, becoming harder to find. The location of subsurface iron ores was difficult to predict. Folds, faults and igneous intrusions caused the ore to appear capriciously in pockets within the iron formation.

Today the mine headframe (shafthouse) still stands as a local monument to this glorious era in Michigan's mining past.

Source:  Photograph by Randy Schaetzl, Professor of Geography - Michigan State University

By the turn of the century mines in Ishpeming were producing more than 2 million tons of ore per year. Shaft mines like this one were extremely prosperous and productive during the early 20th century.

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Some of the images and text on this page were taken from various issues of Michigan History magazine.

This material has been compiled for educational use only, and may not be reproduced without permission.  One copy may be printed for personal use.  Please contact Randall Schaetzl (soils@msu.edu) for more information or permissions.