Lead Industry

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LEAD INDUSTRY

LEAD INDUSTRY first became commercially important to the United States in 1750 when sustained lead mining and smelting began in Dutchess County, New York, and at what later became known as the Austinville mine in Virginia. The demand for lead bullets and shot in the Revolutionary War prompted the working of several small deposits in Massachusetts, Connecticut, Maryland, Pennsylvania, and North Carolina. The domestic availability and relative ease of smelting of lead ores greatly contributed to early frontier development and to sustaining the revolt against the English Crown.

Although reports exist of some petty lead production in connection with a 1621 iron furnace project in Virginia, later investigators have never found evidence of lead occurrences in the vicinity. French trappers discovered lead in the upper Mississippi Valley about 1690, and by 1763 the district near Galena, Illinois, had become a regular lead producer. The French-Canadian, Julien Dubuque, arrived in 1774 and made peace with the local Indians. He operated lead mines and furnaces in Iowa, Wisconsin, and Illinois until his death in 1810. The Fox and Sauk Indian tribes continued to mine and smelt the ore until the 1820s, when white venturers, using black slaves and under strong military protection, largely dispossessed them. This situation, in part, caused the Black Hawk War.

In 1797, Moses Austin migrated from the Virginia district bearing his name (Austinville) to southeast Missouri, where lead had been mined sporadically since about 1724 at Mine La Motte and other mines by early French explorers. Austin set up a large furnace and shot tower on the banks of the Mississippi River in 1798 and by 1819 was producing 3 million pounds of lead per year. With the Louisiana Purchase in 1803, these areas came under the control of the United States.

The simple log furnace—consisting of a crib of logs piled with lead ore, topped by more logs—was of poor smelting efficiency. Thus, when Peter Lorimier built a Scotch hearth in 1834 near Dubuque, Iowa, this new technology greatly lowered production costs and improved productivity within the lead industry. The frontier lead region from Galena into southern Wisconsin and Dubuque developed rapidly, so that by 1845 the district had a population of nearly 10,000 people and reportedly produced 54,495,000 pounds of lead, which was shipped by boat to New Orleans, or by prairie schooner to the Erie Canal and then by boat to eastern markets. Perhaps more than any other factor, early mining and commerce in lead accounted for opening the upper Midwest to American settlers.

From 1845 until the 1860s, domestic lead production continued primarily from shallow galena (lead sulfide) workings within three districts: Austinville, Wisconsin-Illinois-Iowa, and southeast Missouri. Deeper mining had to await renewed exploration during the war periods of the twentieth century. Throughout the Civil War, all these areas were largely controlled by the Confederacy, so that the Union had to melt lead gutters, pewter housewares, and lead pipe for its lead supplies, along with purchasing lead from foreign sources.

In the 1860s and early 1870s, new developments rapidly shifted the locus of the lead industry. With the westward surge of miners and prospectors to the Rocky Mountains following the gold rush of the 1850s came discoveries of lead as a host mineral for some silver and gold. In 1863, lead associated with silver was discovered in Little Cottonwood Canyon in Utah. Completion of the transcontinental railroad in 1869 gave the needed impetus to the growth of the intermountain lead-silver industry, including several smelters in Montana, Idaho, Utah, Nevada, California, and Colorado. Rich silver-lead ore was discovered at Leadville, Colorado, in 1876, and, for a time, this was the world's largest lead-producing area. The large high-grade ore body found at Bunker Hill, Idaho, in 1885 was the basis for the development of the Coeur d'Alene as an important lead-silver-zinc–producing area.

Mining these western lead carbonate ores proved to be much more hazardous to health than mining the lead sulfide ores of the central and eastern states. The human body assimilated carbonate dust more easily than lead in its traditional forms, causing "lead colic," which was most debilitating. In response to the problem, the lead industry initiated the practice of industrial hygiene, using dust respirators and providing a free ration of milk daily to the mine and smelter workers.

At the same time that prospectors were making many new discoveries of lead ore in the West, the shallow occurrences in the southeast Missouri district began to run out. In 1869, the first diamond drill used in the United States arrived from France to the Missouri district, where engineers used it to locate deeper, horizontally bedded deposits of lead ore with thicknesses of up to 500 feet at depths of 120 feet and more. This area of nearly pure lead ore was destined to become one of the largest in the world and a source of great strength to the United States through the wars of the twentieth century. Since 1904, southeast Missouri has been the leading lead-producing area in the United States.

The completion in 1872 of a railway linking Saint Louis and Joplin, Minnesota, in the vicinity of which new ore bodies had been discovered, caused zinc-lead mining activity to accelerate. About 1895, natural gas discoveries were made in the Kansas and Oklahoma part of the Joplin, or tristate, district, providing cheap fuel for zinc smelting and further stimulating mining activities. Since lead was a coproduct of zinc in the ore, lead production also grew, allowing several smelters to be constructed in the area and in the vicinity of Saint Louis.

The lead blast furnace first came into use in the United States in the late 1860s in areas of Nevada, Utah, and Montana, where lower-grade and more-complex lead ores required new technology. Gradually, in the older mining regions, the old furnace, reverberatory, and hearth methods of smelting became outdated. With new concentrating methods of tabling, jigging, and selective flotation, the fine grinding of the ore required to permit upgrading produced unsuitable feed material for the smelters. Adoption of a new technique—sintering (desulfurizing and agglomerating) the fine ore concentrate, then reducing it to lead bullion in a blast furnace—solved the new problems and again gave the lead industry an economic boost. Because the new technologies required greater amounts of capital, they acted as catalysts for a period of consolidation into a few large companies within the lead mining and smelting industry around the turn of the century.

Having provided the lead needs of the nation during the first half of the twentieth century, the older mining districts (Illinois-Wisconsin, Joplin, southeast Missouri "Old Lead Belt," Austinville) gradually became depleted, so that a new find was most welcome. Such was the case with the discovery of a "New Lead Belt" (some 50 miles from the Old Lead Belt) called the Viburnum Trend in southeast Missouri during the late 1950s. As companies developed the mines and came into full production between 1966 and 1974, Missouri lead output more than tripled, approaching a half million tons, or 80 percent of the total U.S. lead production. Two new lead smelters were built in Missouri and the capacity of a third was doubled, while two historic western smelters were being abandoned, indicating the extent of this major shift in mine production.

Once made into a metal, lead is almost indestructible. Water pipes, cisterns, and baths of the pre-Christian era in Rome, and artifacts of the earlier Egyptian and Phoenician civilizations, have been found almost completely intact. Large-scale peacetime reuse of lead became significant in the United States about 1907. Since the 1960s, secondary recovery has accounted for half the domestic lead supply. In 1974, the United States used 1.5 million short tons of lead, which was supplied by 510,000 tons recycled from scrap, 670,000 tons from domestic mines, and the remainder from imports (31 percent from Peru, 26 percent from Canada, 18 percent from Mexico, 11 percent from Australia, and 14 percent from other countries). By the year 2000, more than 60 percent of the industry's production came from recycled materials, primarily because of the large number of scrapped lead batteries.

Historically, lead has been widely used in a variety of consumer products, such as lead-acid storage batteries and organic lead gasoline additives in automobiles. Lead-tin alloys are used for soldering radiators, electrical connections, and tin cans. Sheet lead appears in shielding from nuclear and X-ray radiation and from noise. The corrosion resistance of lead to acids, moisture, and atmosphere accounts for its use in chemical process equipment, electrical cable sheathing, plumbing, and architectural units. Lead compounds have been used as paint pigments, metal primers, ceramic glazes, and insecticides. Because of its density, metal use varies from ballast in the keel of sailboats to shot and bullets for military and sporting ammunition.

Lead and lead compounds can constitute a biological hazard if not properly handled, however, and with the rise of the environmental and consumer movements, this fact has given lead something of a bad reputation. Excessive ingestion and inhalation of lead compounds can result in illness or even death in humans. As a result, increasingly strict regulations have been established for permissible levels of lead in paints and emissions into the atmosphere, particularly in leaded automotive gasoline. This resulted in a dramatic shift in consumer use of lead. As demand for lead in paints, gasoline, and water systems has declined, the use of lead in all battery types expanded to account for 88 percent of the market by the early 2000s. The next-largest demands for the metal are for ammunition and oxides in glass and ceramics—both of which account for about 3 percent of the market.

BIBLIOGRAPHY

Blaskett, Donald R. Lead and Its Alloys. New York: Ellis Horwood, 1990.

Cotterill, Carl H., and J. M. Cigan, eds. Proceedings of AIME World Symposium on Mining and Metallurgy of Lead and Zinc. Vol. 2, Extractive Metallurgy of Lead and Zinc. New York: American Institute of Mining, Metallurgical, and Petroleum Engineers, 1970.

Rausch, D. O., F. M. Stephens, Jr., and B. C. Mariacher, eds. Proceedings of AIME World Symposium on Mining and Metallurgy of Lead and Zinc. Vol. 1, Mining and Concentrating of Lead and Zinc. New York: American Institute of Mining, Metallurgical, and Petroleum Engineers, 1970.

Carl H.Cotterill/c. w.