The Tar Creek Superfund site is located near the Oklahoma/Kansas border in far north-eastern Oklahoma in Ottawa County.
The site comprises a 40-square mile area and is part of the larger Tri-State Mining District that includes areas of Kansas and Missouri and 10 Tribal Nations.
Image: Governor's Task Force Report
The chat was disposed of in piles or in flotation or tailing ponds.
Image: Governor's Task Force Report
From the early 1900s through the late 1970s, the site was mined extensively for lead and zinc ore.
Mining companies began closing doors in 1958. Eagle-Picher was last to leave
in 1970.
The mines produced
- 1.7 MM tons of Lead
- 8.8 MM tons of Zinc
and
Left behind
- 300 miles of tunnels
- 165 MM tons of tailings
- Acid mine drainage
The site covers portions of several communities, including Quapaw Nation, Picher, Cardin, Quapaw, North Miami, and Commerce. Approximately 6,400 residents live within the Superfund site boundaries.
The milling process for the lead and zinc ore resulted in a concentrated form of the original mined material. It also resulted in mine tailings (chat) that were originally considered a waste product.
Some chat piles are as high as 200 feet and contain elevated levels of lead and other heavy metals.
The chat has been sold as a construction product, similar to limestone gravel, for many years.
The chat in flotation ponds has not been quantified.
Note: There is a baseball field between the piles of tailings to the right.
Photo: William Andrews, U.S. Geological Survey,
http://www.usgs.gov
Mine-Water Contamination
Water samples collected between 1983 and 1985 from mine shafts and boreholes in the Picher mining district had concentrations of cadmium as high as 93 µg/L, lead as high as 130 µg/L, and zinc as high as 240,000 µg/L (Parkhurst, 1987).
The U.S. Environmental Protection Agency (EPA) listed the site on the National Priorities List (NPL) in September 1983.
Initially, EPA addressed surface water contamination, which included the mine water discharge.
Water in the abandoned zinc and lead mines in Ottawa County is contaminated, having a low pH and high concentrations of sulfate, fluoride, cadmium, copper, iron, lead, manganese, nickel, and zinc (Christenson, 1995).
These concentrations are much greater than the drinking water standards. The MCL is 5 µg/L for cadmium and 50 µg/L for lead, and the secondary maximum contaminant level (SMCL) is 5,000 µg/L for zinc.
With the later refilling of the shafts with ground-water the dissolution of the sulfate ions occurred. The consequence of this is larger concentration of sulfates.
Source: Imes and Emmett, 1994
Larger concentrations of sulfate in the mining district are likely the end-result of the oxidation of sulfite minerals that developed when the mineshafts were dewatered.
(U.S. Environmental Protection Agency, 1992).
The principal groundwater-bearing units within the Superfund site are the Mississippian Boone Formation and the Cambro-Ordovician Roubidoux Formation.
Source of Image above:
http://www.owrb.state.ok.us/studies/reports/
reports_pdf/boone.pdf#search='Noel%20I.% 20OsbornTechnical%20Report%20GW2001\
The Boone Formation is an important aquifer in areas surrounding the Picher mining district and is the origin of base-flow to streams in the Picher mining district.
The shallow Boone Aquifer is contaminated (See image to left).
The contaminated water from the mining district has the capability to breakdown the quality of freshwater from vertical and lateral flow in Tar Creek and to contaminate open abandoned wells leading to the Roubidoux Aquifer, the source of municipal water supplies.
Because the groundwater flows westward in the Picher mining district area the contaminated water is likely to travel slowly to the west, too.
(Hittman Associates, 1982).
In 1995, the Environmental Protection Agency (EPA) began sampling area soils. Due to findings of elevated lead levels in soils, the EPA began yard remediation activities that are still being conducted.
The EPA have entered into an Administrative Order of Consent with several agencies to investigate the site and provide the information needed to begin cleanup of chat piles, flotation ponds, and mill ponds.
(Christenson and others, 1994; Imes and Emmett, 1994; Reed and others, 1995).
Many tribes are located in the Northeastern portion of Ottawa County. Tribal members use foods grown in contaminated soil for medicinal & ceremonial purposes.
This increases their risk of consumption.
Source: Cherokee Nation website
Quapaw Tribe Powwow grounds in Superfund Site
Oxidation of these minerals through the mining process can release soluble metals in an acidic solution, as shown in the following simplified reaction equation:
4 FeS2 + 15 O2 + 14 H20 ----> 4 Fe(OH)3 + 8 SO4-2 + 16 H +
Source: USGS website, S. Christenson report
The photo above is an example of Tar Creek's acid mine water effects on vegetation.
Similar reactions are possible with sulfides of lead (galena) and zinc (sphalerite). Other trace metals are also associated with these ores and may be released into solution by oxidation-reduction reactions.
Water, which has been discharging from the abandoned mines since the late 1970's, is a potential source of contamination for aquifers in the area and to Tar Creek, which drains much of the Picher district. Tar Creek and Beaver Creek are both impacted by acid mine drainage. (Christenson, 1995).
Contaminated mine water could flow vertically into the overlying Pennsylvanian minor groundwater basin or the underlying Roubidoux aquifer if wells are not properly cased and sealed through the Boone aquifer. Pumping wells completed in the Boone aquifer have the potential to change the direction of lateral water movement and induce the encroachment of contaminated mine water into uncontaminated water.
The headwaters of Tar Creek are located in Cherokee County, Kansas. The creek flows southward through the Superfund site and into the Neosho River. Lytle Creek is a major tributary of Tar Creek.
The headwaters of Beaver Creek are north of Quapaw. The creek flows through the Quapaw powwow grounds and into the Spring River.
There are now concerns for our lakes as well--after all, as the "Grand River Keeper" noted in the 2005 Tar Creek National Conference fish spawn in our contaminated rivers and spend the rest of the time in our lakes.
