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Scientific Investigations Report 2005-5202

In cooperation with the Missouri Department of Natural Resources

Assessment, Water-Quality Trends, and Options for Remediation of Acidic Drainage from Abandoned Coal Mines Near Huntsville, Missouri, 2003—2004

By: Eric D. Christensen


Water from abandoned underground coal mines acidifies receiving streams in the Sugar Creek Basin and Mitchell Mine Basin near Huntsville, Missouri. A 4.35-kilometer (2.7-mile) reach of Sugar Creek has been classified as impaired based on Missouri's Water Quality Standards because of small pH values [< (less than) 6.5]. Samples collected from Sugar Creek from July 2003 to June 2004 did not have pH values outside of the specified range of 6.5 to 9.0. However, large concentrations of iron [416 to 2,320 mg/L (milligrams per liter)], manganese (8.36 to 33.5 mg/L), aluminum (0.870 to 428 mg/L), and sulfate (2,990 to 13,700 mg/L) in acidic mine drainage (AMD) from two mine springs as well as small and diffuse seeps were observed to have an effect on water quality in Sugar Creek. Metal and sulfate loads increased and pH decreased immediately downstream from Sugar Creek's confluence with the Calfee Slope and Huntsville Gob drainages that discharge AMD into Sugar Creek. Similar effects were observed in the Mitchell Mine drainage that receives AMD from a large mine spring. Comparisons of water-quality samples from this study and two previous studies by the U.S. Geological Survey in 1987–1988 and the Missouri Department of Natural Resources in 2000–2002 indicate that AMD generation in the Sugar Creek Basin and Mitchell Mine Basin is declining, but the data are insufficient to quantify any trends or time frame. AMD samples from the largest mine spring in the Calfee Slope subbasin indicated a modest but significant increase in median pH from 4.8 to 5.2 using the Wilcoxan rank-sum test (p <0.05) and a decrease in median specific conductance from 5,000 to 3,540 µS/cm (microsiemens per centimeter at 25 degrees Celsius) during a 17-year period. AMD samples from the largest mine spring in the Mitchell Mine Basin indicated an increase in median pH values from 5.6 to 6.0 and a decrease in median specific conductance from 3,050 to 2,450 µS/cm during the same period.

Remediation of AMD at or near the sites of the three largest mine springs is geochemically feasible based on alkalinity addition rates and increased pH determined by cubitainer experiments and geochemical mixing experiments using the computer model PHREEQCI. Alkalinity values for seven cubitainer experiments conducted to simulate anoxic treatment options exceeded the targeted value for alkalinity [90 mg/L as calcium carbonate (CaCO3)] specified in Missouri's Total Maximum Daily Load program by 18 percent or more, but maximum pH values were between 6.2 and 6.3, which is less than the targeted pH value of 6.5. Treatment of AMD by mixing with stream water or sewage effluent can further increase pH as indicated by geochemical modeling, but will not totally achieve water-quality goals because of limited discharges. A combination of treatments including settling ponds, oxic or anoxic limestone drains, and possibly successive alkalinity producing systems to remediate AMD will likely be required in the Sugar Creek Basin and Mitchell Mine Basin to consistently meet Missouri's Water Quality Standards.




Purpose and Scope

Description of Study Area

Previous Studies

Water Chemistry of Acidic Mine Drainage

Mine Drainage and Stream Remediation



Water-Quality Site Selection, Sampling, and Analysis

Cubitainer Experiments, Geochemical Modeling, and Calculation of Loads

Assessment of Acidic Mine Drainage and Effects on Receiving Streams

Huntsville Gob Subbasin

Calfee Slope Subbasin

Sugar Creek

Mitchell Mine Basin

Water Quality Trends

Characterization and Options for Remediation of Acidic Mine Drainage

Cubitainer Experiment Results

Geochemical Modeling Results

Remediation Options

Summary and Conclusions

References Cited



1.   Map showing location of Sugar Creek Basin, Huntsville Gob, Middle Creek, and Calfee Slope subbasins, Mitchell Mine Basin, and sampling sites in Randolph County, Missouri

2–4. Graphs showing:

2.  Average monthly temperatures measured and recorded at Moberly, Missouri, for
July 2003 through September 2004 and for the 69-year period of record

3.  Average monthly precipitation measured and recorded at Moberly, Missouri, for
July 2003 through September 2004 and for the 69-year period of record

4.  Daily precipitation measured and recorded at Moberly, Missouri, for July 2003
through September 2004

5.  Generalized stratigraphy in the Sugar Creek Basin and vicinity

6.  Map showing location of the top of the Bevier-Wheeler coals inferred outcrop line and
reclaimed mine lands based on field observations

7.  Photograph showing acidic mine drainage in an open limestone channel downstream
from the Huntsville Gob reclamation project looking north from sampling site HG-7S

8.  Photograph showing iron and possibly aluminum flocculants and precipitates that clog
stream beds on the east side of the Huntsville Gob reclamation project

9.  Flow chart showing options for the passive treatment of acidic mine drainage

10. Graph showing relation of dissolved total iron concentrations determined by inductively
coupled plasma methods and by colorimetric methods

11. Schematic of a cubitainer setup used for experiments to evaluate alkalinity addition rates

12. Graph showing comparison of pH and calculated net alkalinity for acidic mine drainage
measured at mine springs and receiving streams, Sugar Creek, and sewage effluent

13–16. Graphs showing discharge, specific conductance, pH, and net alkalinity, and iron,
        manganese, aluminum, and sulfate concentrations for:

13. Huntsville Gob subbasin with distance downstream

14. Calfee Slope subbasin with distance downstream

15. Sugar Creek Basin with distance downstream

16. Mitchell Mine Basin with distance downstream

17–19. Boxplots of pH, specific conductance, and alkalinity, and sulfate concentration for
        sampling sites with multiple samples collected from 1987 to 2004 in the:

17. Calfee Slope subbasin

18. Sugar Creek Basin

19. Mitchell Mine Basin

20. pe-pH diagram of the system Fe-O-H2O-S-CO2 at 25 degrees Celsius, assuming ferrihydrite as the Fe(III) oxy-hydroxide phase, activity of SO42- equal to 0.05, and PCO2 equal to 10 kilopascals

21–23. Graphs showing changes in effluent pH and alkalinity concentration with elapsed time for
        cubitainer experiments conducted under:

21. Closed or open conditions with acidic mine drainage in contact with limestone from mine spring sites HG-2M (A-C) and CS-5M (D-F) and surface-water site HG-7S (G, H)

22. Open conditions with acidic mine drainage in contact with limestone from minespring site CS-5M (I) and surface-water site HG-7S (J, K)

23. Closed conditions with water in contact with limestone from monitoring well sites MW 04-01 (L), MW 04-02 (M), and MW 04-03 (N)



  1.    Location of surface water, mine springs, and underground mine sample sites near Huntsville, Missouri, sampling schedule, and constituents analyzed during 2003–2004
  2.    Values for selected physical properties and dissolved constituent concentrations used in the computation of saturation indices and geochemical mixing calculations
  3.    Values for selected physical properties and saturation indices computed by the program PHREEQCI for selected minerals dissolved in mine springs and ground water
  4.    Values for selected physical properties and dissolved constituent concentrations, and calculated loads for stream water and acidic mine drainage
  5.    Values for physical properties and constituent concentrations for stream water, abandoned mine drainage, and underground mine water
  6.    Influent and effluent measurements of selected physical properties and results of analyses of dissolved constituent concentrations from cubitainer experiments
  7.    Selected physical properties, dissolved constituent concentrations, and saturation indices of selected minerals dissolved in surface water and acidic mine drainage used in geochemical mixing experiments and results
Conversion Factors and Datum
Multiply     By


To obtain
centimeter (cm)   0.3937   inch (in.)
millimeter (mm)   0.03937   inch (in.)
micrometer (µm)   0.0000394   inch (in.)
meter (m)   3.281   foot (ft)
kilometer (km)   0.6214   mile (mi)
square meter (m2)   0.0001   hectare
hectare (ha)   2.4710   acre
square kilometer (km2)   0.3861   square mile (mi2)
liter (L)   0.2642   gallon
liter (L)   0.03531   cubic foot (ft3)
    Flow Rate    
liter per second (L/s)   15.85   gallon per minute (gal/min)
liter per second (L/s)   0.03531   cubic foot per second (ft3/s)
liter per minute (L/min)   0.2642   gallon per minute (gal/min)
kilogram   2.205   pound avoirdupois (lb)
kilogram per day (kg/d)   0.001102   ton per day (ton/d)
metric ton   1.1023   ton, short (2,000 lb)
Kilopascal (kPa)   0.009869   atmosphere, standard (atm)

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:
° F = (1.8 x °C) + 32

Specific conductance is given in microsiemens per centimeter at 25 degrees Celsius (µS/cm at 25 °C).

Concentrations of chemical constituents in water are given either in milligrams per liter (mg/L) or micrograms per liter (µ/L).

Vertical coordinate information is referenced to the North American Vertical Datum of 1988 (NAVD 88).

Horizontal coordinate information is referenced by the North American Datum of 1983 (NAD 83).

Elevation, as used in this report, refers to distance above the vertical datum.


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For more information about USGS activities in Missouri contact:


U.S. Geological Survey

Missouri Water Science Center

1400 Independence Road

Rolla, Missouri 65401

Telephone: (573) 308-3667

Fax: (573) 308-3645

or access the USGS Missouri Water Science Center home page at:

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