Lead and Zinc Mining

The discovery of blackjack (a kind of zinc ore) on the Cook Forty in Galena in 1870 marked the beginning of a century of lead and zinc mining in the Kansas part of the Tri-State mining district. The Tri-State mining district of southwestern Missouri, southeastern Kansas, and northeastern Oklahoma was one of the major lead and zinc mining areas in the world. For one hundred years (1850-1950), the district produced 50 percent of the zinc and 10 percent of the lead in the United States.

Lead and zinc deposits in Kansas occur within the region called the Ozark Plateau in extreme southeastern Cherokee County. This region is defined by outcrops of Mississippian rocks (the oldest surface rocks in the state), which formed about 345 million years ago. The Ozark Plateau covers about 55 square miles in Kansas and includes the towns of Baxter Springs and Galena.

The first commercial ore discovery in the district was made in southwest Missouri around 1838. Production from the Tri-State district peaked between 1918 and 1941. There were more than 11,000 miners working in the area, and perhaps three times as many were involved in support work and industries.

Although zinc was much more common than lead throughout the Tri-State mining district, production up to 1869 was confined to lead, which could be easily smelted in homemade furnaces. Zinc production took off in the early 1870's, following the completion of railroad lines and the construction in 1873 of a coal-fired zinc smelter at Weir City, Kansas (fueled by coal from nearby mines). In 1878 another smelter was built at Pittsburg, Kansas. In the early 1900's, smelting costs were reduced by the discovery of a shallow gas field in southeastern Kansas. Using this cheap fuel source, new gas-fired smelters were built in southeast Kansas, displacing the coal-fired smelters.

During the life of the district, more than 4,000 mines produced 23 million tons of zinc concentrates and four million tons of lead concentrates. The Kansas part of the Tri-State district produced more than 2.9 million tons of zinc, with an estimated value of $436 million, and 650 thousand tons of lead worth nearly $91 million.

In general, mining was done underground, using room and pillar methods, in which room-shaped areas are mined and similarly shaped areas are left for roof support, resulting in a checkboard-like arrangement of alternating rooms and pillars. Underground rooms had walls 25 to 100 feet high and pillars 20 to 50 feet thick. In the eastern part of the district, however, the ore was closer to the surface. Surface mining was common around Galena, Kansas, which became known as a poor man's mining district because small claims could be easily worked.

Many of the rock layers that were mined for ore were also aquifers, or water-bearing formations. Thus, water often came into the mines through these rock layers. To keep the mines from filling with water, as many as 63 pumping plants operated 24 hours a day to remove huge amounts of water. For example, in 1947, more than 36 million gallons of water were pumped from the mines every day (this is enough to cover one acre of ground with water 110 feet deep).

After World War II, production in the Tri-State mining district gradually declined until 1970 when the last active mine, located two miles west of Baxter Springs, Kansas, shut down due to environmental and economic problems.

Environmental Consequences

Lead and zinc mining left behind a number of physical hazards and environmental problems. Over the years, physical hazards such as open mine shafts, collapsed mine shafts, and subsidence areas have claimed lives, caused property damage, and created avenues for water to enter and leave the mines. Subsidence was often a result of the final phase of mining, known as "robbing the pillars," which involved mining the pillars that supported the mine roof. Without these supports, the mine collapsed, eventually causing subsidence at the surface.

color photo of collapsed area filled with stagnant water

Subsidence feature from collapse of one of the deeper lead and zinc mines in Cherokee County.

In the early 1980's, the U.S. Bureau of Mines, in cooperation with state geological surveys, conducted detailed studies of the physical hazards associated with the old mining areas. The studies identified more than 1,500 open shafts and nearly 500 subsidence collapse features in the Tri-State. A total of 599 mine hazards were found in and around Galena, many of which were concentrated in an area known as "Hell's Half Acre." In 1994 and 1995, the U.S. Enivironmental Protection Agency (EPA) and local citizens filled in all the mine collapses and shafts in the town of Galena, Kansas. New top soil was hauled to cover the chat and boulders in the area.

color photo of greatly disturbed landscape outside Galena before reclamation

Galena area before reclamation.

  color photo of smooth, grass-covered landscape outside Galena after reclamation

Galena area after reclamation.

The hundred years of mining also left the region with serious environmental problems. When the mines closed, the pumping stopped, and the abandoned tunnels filled with water. The water in these tunnels became contaminated by iron sulfide (from pyrite and marcasite), which remained in the mine walls or was left behind by the miners, as well as by other metallic sulfides found in the mines. In addition to becoming very acidic, the water contained dissolved metals, some of which are very toxic. This water, in turn, contaminated local ground water, springs, and surface water.

color photo of stream with band rust-colored water flowing into it

Water contaminated by iron sulfide flows into stream across the state line near Picher, Oklahoma.

Lead and zinc production involved crushing and grinding the mined rock to standard sizes and separating the ore. This left behind piles of leftover rock called tailings that covered 4,000 acres in southeastern Cherokee County. These wastes were also a source of contamination. Lead, zinc, and cadmium from the tailings leached into the shallow ground water, contaminating local wells, and runoff moved contaminants into nearby streams and rivers. Wind also blew fine metal-bearing dust (from tailings piles and roads made of tailings) into the air, spreading the contamination to nearby non-mined areas. Radon gas from the mining operations was detected in the air around Galena. During the 1980's, this area was considered one of the most environmentally blighted in the nation.

Some of the cleanup efforts are funded by the U.S. Environmental Protection Agency's Superfund. The EPA began working in the area in the early 1980's and work is ongoing. The EPA divided the Cherokee County Site into six subsites that correspond to six general mining locations, including the areas around Galena, Baxter Springs, and Treece, Kansas.

Because the area in and around Galena had some of the worst contamination, early cleanup efforts were centered there. Chief among these was the provision of safe water supply for rural residents whose wells had been contaminated. Two new wells were constructed in the deep aquifer, and a new rural water district was formed that currently provides over 500 households with a long-term source of clean drinking water.

From 1997 to 1999, contaminated soil was removed from 602 residential properties in Galena and replaced with clean backfill and grass sod or seed; fifty additional properites were remediated in 2000 and 2001. Remediation of residential soils has been completed in Treece and is ongoing in Baxter Springs. Cleanup continues at other sites in southeastern Kansas. For more information, check the EPA Region 7's website: http://www.epa.gov/region07/index.html.

Sources

Buchanan, Rex C., and McCauley, James R., 1987, Roadside Kansas--A Traveler's Guide to Its Geology and Landmarks: Lawrence, Kansas, University Press of Kansas, 365 p.

EPA Region 7, Programs, Superfund, National Priorities List Fact Sheet, Cherokee County, Kansas: http://www.epa.gov/region7/cleanup/npl_files/ksd980741862.pdf (May 5, 2005).

McCauley, J. R., Brady, L. L., and Wilson, F. W., 1983, A Study of Stability Problems and Hazard Evaluation of the Kansas Portion of the Tri-state Mining Area: Kansas Geological Survey, Open-file Report 83-2, 193 p.

Pierce, Robert, 1995, Southeast Kansas--Coal Mines and Fossils: KESTA 4th Annual Fall Conference and Field Trip, October 20 and 21, 1995, Guidebook, 23 p.

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