U. S. DEPARTMENT OF THE INTERIOR 

U. S. GEOLOGICAL SURVEY

Environmental Characteristics of the Abandoned Greenwood Mine Area, Prince William Forest 

Park, Virginia: Implications for Mercury Geochemistry

by

Robert R. Seal, II1 , David P. Haffher1 , and Alien L. Meier2

Open-File Report 98-326

This report is 

standards an 

only and does not imply endorsement by th

^.S. Geological Survey, 954 National Center, Reston, VA 20192

2U.S. Geological Survey, 973 Denver Federal Center, Denver, CO 80225

1998
TABLE OF CONTENTS

ABSll^CT....................................................................................................................^

SCOPE..........................................^

WATER QUALITY....................................................................................................................

IMPLICATIONS FOR MERCURY GEOCHEMISTRY ....................................................................................9

CONCLUSIONS AND RECOMMENDATIONS.......................................................................................... 12

ACKNOWLEDGMENTS.............................................................................................................

REFERENCES..........................................................................................................................

FIGURE 1: Map of Prince William Forest Park ................................................................................................3

FIGURE 2: Map of area around the abandoned Greenwood mine............................................................... 5

FIGURE 3: Plot of Fe2+ /Fetotal vs. dissolved oxygen........................................................................................7

FIGURE 4: Plot of total base metals vs. pH comparing Greenwood data to other low-sulfide

gold deposits..................................................................................................................................................

FIGURE 5: Plot of total base metals vs. pH comparing Greenwood data to the reclaimed Cabin

Branch site and other massive sulfide deposits........................................................................................11

TABLE 1: Comparison of the range of values for various water quality parameters .............................~ 6

TABLE 2: Comparison of heavy metal concentrations with water quality standards ............................ 10

APPENDIX 1: Field and Analytical Methods................................................................................................15

APPENDIX 2: Descriptions of Sample Sites................................................................................................ 16

APPENDIX 3: Water Quality Data................................................................................................................17

ABSTRACT

This report presents water quality data for samples collected in December, 1997 from the 

abandoned Greenwood mine area in Prince William Forest Park, Prince William County, Virginia. 

Data include temperature, pH, specific conductance, dissolved oxygen, alkalinity, flow, and total acid 

soluble and dissolved major and trace element concentrations for four sites around the mine workings. 

Data are interpreted in terms of their implications for the geochemical behavior of mercury.

SCOPE

The National Park Service acquired a 43-acre tract of land in Prince William County, Virginia 

for incorporation into Prince William Forest Park in July, 1997 (Fig. 1). The abandoned Greenwood 

gold mine site is located within the tract. The U. S. Geological Survey conducted reconnaissance 

sampling at the site in December, 1997 to: (1) assess water quality at the site; and (2) assess the 

environmental impact on the surrounding ecosystem. Also in December, 1997, the National Park 

Service collected six samples in a reconnaissance soil geochemical survey at the site. During this 

survey, the National Park Service identified Hg concentrations of over 40 mg/kg (C. Pollio, personal 

communication, 1998). Mercury amalgamation is known to have been used extensively in historic 

gold mining operations in the eastern United States (Callahan et al., 1994; Sweet, 1980).

The Greenwood mine is a gold property that is located in Prince William County at the 

northeastern end of the 175 km-long Virginia gold-pyrite belt, also known as the Virginia volcanicplutonic belt (Pavlides et al., 1982). The Greenwood deposit is hosted by the Ordovician 

(approximately 475 million year old) Lake Jackson pluton. The Lake Jackson pluton is a 

metamorphosed tonalitic intrusion. Tonalites consist of subequal proportions of quartz and sodiumand calcium-rich feldspar. The gold deposits of the Virginia gold-pyrite belt are typically classified as 

low-sulfide gold-quartz deposits. This type of deposit generally consists of quartz veins with minor 

amounts of pyrite and gold (Goldfarb and others, 1995). Although exposures are poor, the 

Greenwood deposit probably conforms to this classification.
77°22'30"

Cabin 

Branch Mine

38° 

37' 

30"

Figure 1: Map of Prince William Forest Park. Park boundary is shown as heavy dashed 

line. Streams are shown as thin solid lines. Ponds and lakes are shown as stippled 

patterns. The 43-acre tract containing the Greenwood site is shown as gray.
Reports in the published literature on the mine are scarce. Lonsdale (1927) reported that two 

vertical shafts were sunk, which are still identifiable. He also noted that the mine has been abandoned 

at least since 1907. The mine site is located at the headwaters of Quantico Creek, which flows past the 

reclaimed Cabin Branch mine, approximately 11 km downstream (Fig. 1). Elsewhere in Prince 

William County, Pardee and Park (1948) described placer operations at the Crawford property on 

Neabsco Creek and its tributaries, located approximately 10 km east of the Greenwood mine. The 

placer was worked around 1935 and a small amalgamation plate was used to extract the gold.

WATER QUALITY 

Sample Sites

To date, four surface-water samples have been collected and analyzed from the Greenwood 

mine site in Prince William Forest Park (Fig. 2). These samples included water within shafts (2), a 

man-made pond upstream from the shafts, and the small stream (headwaters of Quantico Creek) that 

flows past the site. The stream sample was taken downstream of the shafts at the boundary of the 43- 

acre tract.

One shaft (PWGM-1-1) contained abundant organic debris (sticks, leaves, etc.) and the water 

in the shaft was dark brown and covered by an iridescent bacterial film. A distinct sulfurous odor was 

also noted. The other shaft (PWGM-4-1), north of the first along a shallow trench, was filled with light 

brown water with a less well developed bacterial film. A less distinct sulfurous odor was also noted.

At each site, two splits were collected for cation analysis; one split was unfiltered and the 

other split was filtered through a 0.45 um filter. The collection of two splits was done to assess 

qualitatively the transport of heavy metals adsorbed on fine-grained suspended particulate matter. 

Field and laboratory procedures are summarized in Appendix 1. In the context of the Greenwood site, 

mercury (Hg) is notably absent from the suite of elements analyzed; future work should remedy this 

deficiency. Descriptions of the sampling sites are presented in Appendix 2.

Results

Complete analyses of all water samples are presented in Appendix 3. General characteristics 

of water quality are summarized in Table 1; salient features are highlighted below. The waters 

sampled from within the shaft depressions are considerably different from the pond and stream 

samples. The pH values of all samples were slightly acidic and ranged from 5.9 to 6.4. The specific 

conductance ranged from 112.3 to 311.0 uS/cm, which corresponds to an approximate range of total 

dissolved solids of 73 to 200 mg/L. All dissolved oxygen levels were well below saturation. 

Dissolved oxygen ranged from 5 to 7 mg/L for the stream and pond, respectively, which are 

approximately 39 to 57 % of saturation. Dissolved oxygen values for the waters in the shaft 

depressions were 0.02 and 0.9 mg/L, which are approximately 0.2 and 8 % of saturation, respectively. 

The low oxidation state of the waters from the shaft depressions is also reflected in the Fe2+/Fetotal 

ratios, where the shaft waters have values between 0.75 and 0.85. In addition, there is a broad 

negative correlation between Fe2+ /Fetotal and dissolved oxygen (Fig. 3).

Dissolved sulfate values for the stream and pond average 16.5 mg/L, whereas the sulfate 

concentration of the shaft water at PWGM-1-1 was 0.38 mg/L and that at PWGM-4-1 was 69.0 mg/L. 

Total dissolved iron values are low in the stream and pond (<0.34 mg/L); the values from the water in 

the shaft depressions are higher (7.1 and 33.0 mg/L) and presumably reflect a combination of the 

greater solubility of reduced iron (Fe2+) compared to oxidized iron (Fe3+) and the greater solubilty of 

total iron due to complexation with dissolved organic carbon (DOC) compounds. The brown color of 

the shaft waters is consistent with high DOC. Dissolved aluminum (up to 0.29 mg/L), and total base 

metals (copper + zinc + nickel + cobalt + cadmium + lead; up to 0.05 mg/L) values are generally low 

compared to waters around the Cabin Branch mine site (Fig. 4). Alkalinity values range from 23.0 to
^

JPWGM-2-1

Figure 2: Map of 43-acre tract surrounding the abandoned Greenwood mine site. Tract boundary is shown as 

heavy dashed line. Topographic contours are shown as light dashed lines, in feet. Quantico Creek is shown by 

solid line. Roads are shown as dark stippled pattern and ponds are shown as light stippled pattern. Sample sites 

are labeled.
Table 1. Comparison of the Range of Selected Water Quality Parameters for Filtered Samples.

Greenwood Shafts Cabin Branch*

Ground Waters

pH

Specific Conductance

uS/cm

Dissolved Oxygen

mg/L

Alkalinity

mg/LCaCO3

SO4

mg/L

Hardness

mg/L CaCO3

Fe

Mg/L

Al

Mg/L

Cu

Zn

Mg/L

Cd

Mg/L

Pb

Mg/L

Total Base Metals

High

6.1

311.0

0.9

69.8

69.0

124.2

33,000.0

290.0

8.0

27.0

0.1

8.3

0.046

Low

5.9

155.0

0.02

36.2

0.38

27.8

7,100.00

220.0

0.7

3.0

<0.02

0.4

0.014

High

7.0

2,050.0

2.6

209.4

1,200.0

1,232.5

17,000.0

5,500.0

3,300.0

11,000.0

20.0

12.0

14.434

Low

4.1

433.0

0.5

0.0

200.0

141.0

190.0

<0.01

3.0

36.0

0.2

<0.05

0.058

Cabin Branch*

Seeps

High

6.9

1,550.0

9.0

201.6

790.0

655.0

39,000.0

1,100.0

1,300.0

13,000.0

35.0

2.8

14.446

Low

5.7

557.0

0.05

1.2

260.0

250.6

85.0

<0.01

1.0

390.0

0.2

<0.05

0.452

Quantico Creek Qu

Greenwood Area Cabi

High

6.4

198.7

7.0

29.2

17.0

40.5

340.0

180.0

3.0

41.0

0.2

0.3

0.047

Low

6.2

112.3

5.0

23.0

16.0

30.2

220.0

45.0

2.0

5.0

0.03

0.2

0.008

H

13

1

1

4

4

32

6

1

33

mg/L 

*Cabin Branch data are from R.R. Seal, II, unpublished data, 1998.
 Greenwood Shafts

 Quantico Creek

E3 Cabin Branch Wells 

Jill Cabin Branch Seeps

5.0 10.0

D.O. mg/L

15.0

Figure 3: Plot of Fe2+ /Fetotai vs. dissolved oxygen (D.O.). Cabin Branch data are 

from R.R. Seal, n, unpublished data (1998). Quantico Creek data indicated by 

small circles are from the vicinity of the Cabin Branch mine and are from R.R. 

Seal, II, unpublished data (1998). Note that low oxidation states are represented 

by low D.O. levels and high Fe2+/Fet0tal values. The scatter of the Cabin Branch 

well data to low Fe2+/Fet0tal values at a fairly constant D.O. value indicates 

oxidation-reduction disequilibrium in the well waters.
U

ZHJ

O

U

U

+

.5

100,000

10,000

1,000

100

10

1

0.1 

0.01

0.001

Iron Mtnv 

California

O Quantico Creek

H Greenwood Shafts

 Cabin Branch Seeps

23 Cabin Branch Wells

-1.0 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0

pH

Figure 4: Plot of total base metals vs. pH. Increasing size of Quantico Creek Symbols 

and arrows qualitatively indicate distance downstream from headwaters. Medium 

sized symbols are for samples taken a short distance upstream of the Cabin Branch 

mine site; large symbols are for samples taken downstream of the Cabin Branch mine 

site. Cabin Branch data and Bald Mountain, Maine data are from R.R. Seal, II, 

unpublished data (1998). Iron Mountain, California data are from Alpers et al. (1994). 

Data from Iron Mountain and Bald Mountain are plotted for comparison purposes and 

represent the extremes of water quality values associated with massive sulfide deposits 

similar to the Cabin Branch mine. Iron Mountain is an U.S.E.P.A. Superfund site. Bald 

Mountain is an unmined deposit; thus, all water chemistry signatures represent natural 

background values.
69.8 mg/L CaCO3 for all samples. Hardness values for all samples vary between 27.8 and 124.2 mg/L 

CaCO3 equivalent.

Comparison with Water Quality Standards

The dissolved heavy metal concentrations of the Greenwood area waters are summarized in 

Table 2 and compared with U.S.E.P.A. (1996) water quality standards for acute effects (criterion 

maximum concentrations; CMC) in freshwater aquatic systems. For the heavy metals cadmium, 

chromium, copper, lead, nickel, silver, and zinc, the toxic effects decrease with increasing water 

hardness. For comparison purposes, CMC values for these metals are calculated for the low and high 

limits of water hardness values observed in the shaft depressions and are presented in Table 2. 

Heavy-metal water quality for all samples from the Greenwood area meet the U.S.E.P.A. (1996) 

standards with the exception of copper from sample PWGM-1-1 from the shaft depression. Here, the 

measured concentration was 8.0 Mg/L, compared to the CMC of 5.1

Comparison with Other Gold Deposits

The environmental signatures of low-sulfide gold deposits, such as the Greenwood deposit, 

have been summarized by Goldfarb et al. (1995). For the class as a whole, the potential for adverse 

environmental impacts are considered minimal from a geologic perspective because the low sulfide 

and base-metal content is not likely to result in heavy-metal laden acid mine drainage. Furthermore, 

this type of deposit can be characterized by carbonate alteration which can naturally mitigate acid 

drainage. However, the greatest potential threat to environment comes from irresponsible mineral 

processing practices, chief among these for the Greenwood site is the use of mercury amalgamation to 

concentrate gold.

From a geologic perspective, the Greenwood waters are indistinguishable from other mine 

waters from low-sulfide gold deposits in terms of pH and dissolved base metal concentrations 

(Cieutat et al., 1994; Trainor et al., 1995; Fig. 5). Compared to waters around the reclaimed Cabin 

Branch pyrite mine, the Greenwood waters have much lower heavy-metal concentrations as would be 

expected from geologic considerations (Fig. 4).

IMPLICATIONS FOR MERCURY GEOCHEMISTRY 

Anatomy of a Mercury Amalgamation Facility

Mercury amalgamation is a common technique that has been used in gold mining operations 

historically; it is also used today in less developed countries in South America, Asia, and Africa 

(Lacerda, 1997; Sweet, 1980). For small-scale operations, it offers the advantages of being cheap, 

reliable, and portable. Its wide-spread use has resulted in adverse environmental impacts; mercury 

poisoning related to gold mining has been reported in Brazil, China, and the Philippines (Lacerda, 

1997). Pardee and Park (1948) reported the use of copper-plate mercury amalgamation around 1935 in 

Prince William County at the Crawford property east of the Greenwood site. Details of the mineral 

processing techniques at the Greenwood site are not available, but the use of copper-plate 

amalgamation at the nearby Crawford property suggests that the same process may have been used at 

Greenwood.

Mercury is used to separate fine gold particles through amalgamation in both placer and 

hard-rock mining operations. In hard-rock mining operations, the ore is first crushed, then the ore 

typically undergoes a gravimetric concentration step. The concentrate is then washed over mercury, 

or mercury amalgamated to a copper plate (generally 0.3 to 1.0 cm thick); the mercury readily alloys 

with gold. The alloy or amalgam is then typically roasted in open air to vaporize the more volatile 

mercury and leave the gold behind (Lacerda, 1997; Sweet, 1980). Interestingly, the high dissolved
Table 2. Comparison of Heavy Metal Concentrations of Greenwood Mine Site Filtered Water Samples with R

PWGM-1-1 PWGM-4-1

Hardness (mg/L CaCO3)

As(ug/L)

Cd2 (ug/L)

Cr2-3 (ug/L)

Cu2 (ug/L)

Pb2 (ug/L)

Ni2 (ug/L)

Se(ug/L)

Ag^g/L)

Zn2 (ug/L)

Standards are U.S.E.P.A.

^MC values for these ele

Shaft

27.8

0.4

0.1

<0.5

8.0

8.3

2.2

0.3

<0.01

27.0

Criterion 

iments var

Shaft

124.2

1.0

<0.02

<0.5

0.7

0.4

3.9

0.6

<0.01

3.0

PWGM-2-1

Quantico Creek

40.5

<0.2

0.2

<0.5

3.0

0.2

1.9

0.5

<0.01

41.0

Maximum Concentrations for acute toxicity 

v as a function of the hardness of the water d

PWGM-3-1

Lower Pond

30.2

<0.2

0.03

<0.5

2.0

0.3

0.9

0.4

<0.01

5.0

in freshwater aquatic 

see U.S.E.P.A.. 1996}.

Freshw

3

1

4

system

Low CM

the lowest observed hardness value; high CMC values are calculated using the highest observed hardness va

3CMC values are for Cr (III).
U

o 

U

U

c

N

100

10

o.i

0.01

0.001

 Greenwood Shafts 

O Quantico Creek 

Cabin Branch Seeps 

Cabin Branch Wells

Low Sulfide 

Gold Deposits

3.0 4.0 5.0 6.0 7.0 8.0 9.0

pH

Figure 5: Plot of total base metals vs. pH. Increasing size of Quantico Creek symbols 

and arrows qualitatively indicate distance downstream from headwaters. Medium 

sized symbols are for samples taken a short distance upstream of the Cabin Branch 

mine site; large symbols are for samples taken downstream of the Cabin Branch mine 

site. Cabin Branch data are from R.R. Seal, II, unpublished data (1998). Field for lowsulfide gold deposits is defined by data from Cieutat et al. (1994), Goldfarb et al. (1995), 

and Trainor et al. (1995).

11
copper concentrations in sample PWGM-1-1 may be a reflection of the undocumented use of the 

copper-plate amalgamation process at the Greenwood site.

Contamination of the environment with mercury occurs during at least three stages of the 

process. First, some mercury is released in the water that is used to wash the ore concentrate over the 

mercury or copper-mercury plate. Second, some mercury adheres to the processed ore and is 

disposed of on site as solid mine waste. Third, mercury is released to the atmosphere during the 

roasting of the amalgam. Thus, at the abandoned Greenwood site, the greatest potential modern 

threat from mercury used in historic mining operations comes from the solid mine wastes that may 

have been disturbed around the site.

Geochemistry of Mercury

Dissolved mercury can be found in several forms in nature including elemental mercury 

(Hg°), inorganic free mercury (Hg2+), inorganically complexed mercury, organically complexed 

mercury, and methylmercury (CH3Hg+ ), among others. Of these species, methylmercury is the most 

hazardous because it is a neurotoxin, which tends to biomagnify in the food chain in aquatic systems.

Several factors tend to enhance mercury methylation in freshwater aquatic systems; these 

factors include pH, and concentrations of dissolved organic carbon (DOC), oxygen, and sulfate 

(Gilmour and Henry, 1991). The significance of these factors in mercury methylation are related to 

their effects on sulfate-reducing bacteria, such as Desulfovibrio desulfuricans, which are the principal 

methylators of mercury in aquatic systems (Compeau and Bartha, 1985; Gilmour and Henry, 1991; 

Gilmour et al., 1992). In general terms, the metabolic processes of sulfate-reducing bacteria consume 

sulfate and organic compounds to produce hydrogen sulfide and carbon dioxide; methyl complexes 

which can combine with mercury are a byproduct of this process. Thus, sulfate-reducing bacteria 

tend to thrive in environments that are low in dissolved oxygen, and high in sulfate and organic 

matter. However, in terms of enhanced methylation of mercury, these factors have competing effects. 

At low sulfate concentrations, mercury methylation is inhibited because the metabolism of sulfatereducing bacteria is limited by sulfate availability; at high concentrations, excessive sulfide product 

can sequester mercury from methylation through the formation of mercury sulfide (Gilmour and 

Henry, 1991). Gilmour and Henry (1991) suggested that the optimum range of sulfate concentrations 

for maximum mercury methylation is between approximately 20 and 50 mg/L. Research in the 

Florida Everglades suggests that the optimum range of sulfate concentrations might be lower, from 

approximately 2 to 20 mg/L (W. Orem, written communication, 1998). Likewise, organic matter is 

essential to the metabolism of sulfate-reducing bacteria, and is abundant in the shaft depressions.

In the case of the Greenwood site, the environment documented in the shaft depressions is 

conducive to mercury methylation: dissolved oxygen levels are low, and organic matter is abundant. 

The distinct hydrogen sulfide odor noted at PWGM-1-1 and PWGM-4-1 indicates that sulfatereduction is actively occurring. At PWGM-1-1, the sulfate concentration is abnormally low (0.38 

mg/L) compared to the stream and pond values (16.0 and 17.0 mg/L, respectively) and may indicate 

that the system became sulfate-limited. In contrast, the sulfate concentration at PWGM-4-1 (69.0 

mg/L) was higher than the surrounding stream and pond values. The dissolved oxygen 

concentration at PWGM-4-1 (0.9) was also higher than PWGM-1-1 (0.02) and may suggest that the 

elevated sulfate concentrations are due to secondary oxidation of hydrogen sulfide. Therefore, the 

potential for significant mercury methylation in the shaft depressions is significant.

CONCLUSIONS AND RECOMMENDATIONS

With the exception of copper in PWGM-1-1, the concentrations of heavy metals meet water 

quality standards for freshwater aquatic systems. The pH and heavy metal values from the 

Greenwood area are very similar to those for other low-sulfide gold deposits. Thus, acidity and heavy

12
metals appear to pose no significant environmental threat around the abandoned mine site. However, 

the case for mercury may be different.

Dissolved mercury concentrations were not measured in the present study. However, 

significant mercury concentrations would not be surprising considering the high mercury level 

reported in soils around the site by the National Park Service, and the fact that mercury amalgamation 

historically was an important gold processing technique. Furthermore, the geochemical environment 

defined for the shaft depressions on the property is condicive to the production of methylmercury, the 

most toxic species of mercury in aquatic systems.

Future work at the site, and downstream, should evaluate the speciation of dissolved mercury 

to determine methylmercury concentrations. Mercury concentrations of fish (whole-body and (or) 

liver) at the site and downstream may be useful in determining the extent of contamination. 

Assuming that the mercury contamination is due to mercury amalgamation used in gold recovery, 

then long-term problems may be associated with residual mercury in solid mine wastes around the 

site. To assess the nature and extent of the problem, soil sampling survey on a grid around the site 

should be conducted to determine the mineralogy and geochemistry of the soils.

ACKNOWLEDGMENTS

The cooperation and assistance of Carol Pollio and Ann Brazinski of the National Park Service 

is greatly appreciated. Gregory Wandless assisted in the water sampling.

REFERENCES

Alpers, C.N., Nordstrom, D.K., and Thompson, J.M., 1994, Seasonal variations of Zn/Cu ratios in acid 

mine water from Iron Mountain, California: in Environmental Geochemistry of Sulfide Oxidation, 

C.N. Alpers and D.W. Blowes, eds., Amer. Chem. Soc. Symposium Series 550, p. 324-344.

Callahan, J.E., Miller, J.W., and Craig, J.R., 1994, Mercury pollution as a result of gold extraction in 

North Carolina, U.S.A.: Applied Geochemistry, v. 9, p. 235-241.

Cieutat, B.A., Goldfarb, R.J., Borden, J.C., McHugh, J., and Taylor, C.D., 1994, Environmental

geochemistry of mesothermal gold deposits, Kenai Fjords National Park, south-central Alaska, in 

Till, A.B., and Moore, T., eds., Geological Studies in Alaska by the U.S. Geological Survey, 1993: 

U.S. Geological Survey Bulletin 2107, p. 21-25.

Compeau, G.C., and Bartha, R., 1985, Sulfate-reducing bacteria: principal methylators of mercury in 

anoxic estuarine sediments: Applied and Environmental Microbiology, v. 50, p. 498-502.

Gilmour, C.C., and Henry, E.A., 1991, Mercury methylation in aquatic systems affected by acid 

deposition: Environmental Pollution, v. 71, p. 131-169.

Gilmour, C.C., Henry, E.A., and Mitchell, R,., 1992, Sulfate stimulation of mercury methylation in 

freshwater sediments: Environmental Science and Technology, v. 26, p. 2281-2287.

Goldfarb, R.J., Berger, B.R., Klein, T.L., Pickthorn, W.J., and Klein, D.P., 1995, Low sulfide Au quartz 

deposits: U.S. Geological Survey Open-File Report OF95-831, p. 261-267.

Lacerda, L.D., 1997, Global mercury emissions from gold and silver mining: Water, Air, and Soil 

Pollution, v. 97, p. 209-221.

Lonsdale, J.T., 1927, Geology of the gold-pyrite belt of the northeastern Piedmont, Virginia: Virginia 

Geological Survey, Bulletin 30,110 p.

Pardee, J.T., and Park, C.F., Jr., 1948, Gold deposits of the southern Piedmont: U.S. Geological Survey 

Professional Paper 213,156 p.

13
Pavlides, L., Gair, J.E., and Cranford, S.L., 1982, Central Virginia volcanic-plutonic belt as host for 

massive sulfide deposits: Economic Geology, v. 77, p. 233-272.

Sweet, P.C., 1980, Processes of gold recovery in Virginia: Virginia Minerals, v. 26, no. 3, p. 29-33.

Trainor, T.P., Fleisher, S., Wildeman, T.R., Goldfarb, R.J., and Huber, C.S., 1995, Environmental 

geochemistry of the McKinley Lake gold mining district, Chugach National Forest, Alaska: U.S. 

Geological Survey Bulletin 2152, p. 47-57.

U.S. Environmental Protection Agency, 1996, Water quality standards, Federally promulgated water 

quality standards: Federal Register, 40 CFR Part 131, p. 611-640.

14
APPENDIX 1: FIELD AND ANALYTICAL METHODS

Water samples were collected in one-liter high-density polyethylene bottles that were doublyrinsed with sample water prior to collection. Samples were divided into four splits for chemical 

analysis: two for cation analysis, one for anion analysis, and one for alkalinity determination. The 

cations splits included filtered (dissolved) and unfiltered (total acid soluble) aliquots. Samples were 

filtered through 0.45 um nitrocellulose filters. Cation splits were stored at ambient temperature in 

acid-washed (10 % HC1) high-density polyethylene bottles and preserved with 1 drop of ultra-pure 

nitric acid per each 10 ml of sample. Anion and alkalinity splits were stored high-density 

polyethylene bottles that were not acid-washed and were refrigerated until the time that they were 

analyzed.

On-site measurements at the time of collection included air temperature, water temperature, 

pH, specific conductance, dissolved oxygen, dissolved ferrous iron, dissolved total iron, dissolved 

sulfate, dissolved nitrate, and water flow. The pH was measured using an Orion 230A pH meter with 

a 91-07probe, calibrated with pH = 4.00 and 7.00 buffer solutions. Specific conductance was measured 

with an Orion 135 specific conductance meter. Dissolved oxygen concentrations were determined 

with Chemetrix high-range ampoules or with an Orion 250A meter with an Orion 97-08-99 oxygen 

electrode. Dissolved total iron, ferrous iron, sulfate, and nitrate concentrations were determined in the 

field using a Hach DR2000 spectrophotometer. Alkalinity samples were analyzed by Gran titration 

with0.18NH2SO4.

Cations were analyzed at U.S. Geological Survey (Central Mineral Resources Team) 

laboratories in Denver, CO by inductively-coupled plasma mass spectrometry (ICP-MS). Anions were 

analyzed at U.S. Geological Survey (Water Resources Division) laboratories in Ocala, FL by ion 

chromatography (chloride, and sulfate) and by ion-selective electrode (fluoride).

15
APPENDIX 2: DESCRIPTIONS OF SAMPLE SITES

PWGM-1-1 (NFS GM002): 38° 37.8' N, 77° 26.0' W; Water in main mine shaft at Greenwood Mine; 

deep brown color and iridescent bacterial film on surface; abundant organic debris in 

water; sulfurous odor.

PWGM-2-1:38° 37.8' N, 77° 26.0' W; Quantico Creek downstream from Greenwood Mine area; water 

had clear appearance and no odor; flow rate = 0.3 L/min.

PWGM-3-1:38° 37.9' N, 77° 26.8' W; Lower pond upstream from Greenwood Mine area.

PWGM-4-1 (NFS GM001): 38° 37.9' N, 77° 26.0' W; Water in small mine shaft north of main shaft;

brown color, less distinct sulfurous odor compared to PWGM-1-1, and abundant leaves.

16
SAMPLE NUMBER

Description 

NFS Location 

Collection Date 

Field Parameters 

Air Temperature °C 

Water Temperature °C 

pH

Conductivity |4.S/cm 

Dissolved O2 mg/L

Dissolved (<0.45 (4m) Concentrations 

Alkalinity mg/L CaCO3

N03 mg/L

SO4 mg/L

Fmg/L

Clmg/L

Hardness mg/L CaCO3

Lijig/L

Na mg/L 

Mg mg/L

SiO2 mg/L

Ca mg/L

Cr^ig/L 

Mnjig/L 

Femg/L 

Fe2+ mg/L

Cu^ig/L 

Zn|Ag/L

Pb^ig/L

As |Ag/L 

Se^ig/L

Sr^ig/L 

Y^ig/L 

Zr^ig/L

APPENDIX 3:

PWGM-l-l

Shaft

GM002

12/8/97

6.6

5.2

6.1

155

0.02

s 

36.2

0

0.38

<0.1

1.5

27.8

0.6

0.05

1.7

1.9

290

14

550

2100

8.0

0.5

1.1

0.6

<0.5

720

33.000

22.4

0.64

2.2

8

27

0.1

8.3

0.03

0.04

0.4

0.3

3.3

54

1.3

0.1

WATER-QUALITY DATA

PWGM-2-1 PWGM-3-1

Stream

12/8/97

6.6

4.6

6.2

198.7

5

29.2

1.5

16

<0.1

32

40.5

0.5

<0.05

24

3.9

45

19

51

1800

9.8

<0.1

0.2

<0.1

<0.5

99

0.220

0.07

0.3

1.9

3

41

0.2

0.2

<0.02

<0.02

<0.2

0.5

1.5

57

0.2

<0.05

Pond

12/8/97

6.5

5.9

6.4

112.3

7

23

2.6

17

<0.1

7.4

30.2

0.5

<0.05

12

2.8

180

12

52

1300

7.5

<0.1

1.3

<0.1

<0.5

120

0.340

0.05

0.2

0.9

2

5

0.03

0.3

<0.02

<0.02

<0.2

0.4

1.1

41

0.4

0.07

PWGM-4-1

Shaft

GM001

12/8/97

6.8

7.6

5.9

311

0.9

69.8

4.6

69

0.1

7.2

124.2

3.0

0.2

24

12

220

43

370

1600

30

12

1.3

4

<0.5

260

7.100

8.3

5.8

3.9

0.7

3

<0.02

0.4

<0.02

<0.02

1

0.6

1.5

170

0.73

<0.05

17
SAMPLE NUMBER PWGM-1-1 

Dissolved (<0.45 |Am) Concentrations (cont.)

Nb^ig/L 

Mo (Ag/L

PWGM-2-1 PWGM-3-1 PWGM-4-1

In^ig/L 

Sn^ig/L

Te ng/L 

Cs^ig/L 

Ba^ig/L

Nd ng/L 

Sm^ig/L 

Eu^ig/L 

Tb^ig/L

Dy ng/L 

Ho ng/L 

Er^ig/L 

Tm^ig/L 

Yb^ig/L

Hf>g/L

Ta^ig/L

Re ng/L 

Au (Ag/L

TMg/L

Total Acid Soluble Concentrations

Be ng/L 

Na mg/L

Mg mg/L

SiO2 mg/L

K^ig/L 

Ca mg/L

Sc^ig/L

V^ig/L

Cr^ig/L

Mn|Ag/L

<0.02

0.1

<0.01

<0.01

1

0.2 

<0.1

<0.01

49

1.6

3.6

0.48

2.0

0.38

0.061

0.04

0.35

0.24

0.053

0.12

0.02

0.1

<0.05

<0.02

0.04

<0.02

<0.01

<0.05

0.02

0.62

0.05

0.6

0.05

1.7

1.9

290

14

730

2100

8.0

<0.1

1.1

0.7

<0.5

730

<0.02

0.07

<0.01

<0.01

<0.05

0.1 

<0.1

<0.01

31

0.2

0.4

0.05

0.23

0.04

0.01

0.006

0.060

0.050

0.008

0.02

< 0.005

0.03

<0.05

<0.02

0.02

<0.02

0.02

<0.05

<0.01

0.03

0.03

0.7

<0.05

24

3.9

91

19

62

1700

9.9

0.3

0.1

<0.1

<0.5

100

<0.02

0.07

<0.01

<0.01

<0.05

0.2

<0.1 

<0.01

22

0.3

0.63

0.09

0.38

0.06

0.02

0.01

0.091

0.052

0.02

0.04

< 0.005

0.03

<0.05

<0.02

0.05

<0.02

<0.01

<0.05

<0.01

0.10

0.06

0.5

0.08

12

2.9

300

12

69

1300

7.5

<0.1

0.9

4

<0.5

180

<0.02

0.4

<0.01

<0.01

<0.05

0.09

<0.1 

<0.01

32

0.75

2.0

0.2

0.75

0.1

0.03

0.02

0.13

0.14

0.03

0.072

0.008

0.08

<0.05

<0.02

0.03

<0.02

0.03

<0.05

<0.01

0.15

0.14

2.9

0.2

22

9.6

370

42

450

1500

30

15

2.7

4

<0.5

250

18
SAMPLE NUMBER

Total Acid Soluble Concentrations (cont.)

Femg/L

Co jig/L 

Ni jig/L 

Cu |4.g/L 

Zn|4.g/L 

Cd^g/L 

Pb|ig/L

PWGM-1-1 PWGM-2-1 PWGM-3-1 PWGM-4-1

As |4.g/L 

Se|Ag/L 

Rb ng/L 

Sr |4.g/L

Zr^ig/L

MofAg/L

Ag M-g/L

In|4.g/L 

SnfAg/L 

Sb fAg/L 

Te |4.g/L 

Cs^ig/L

La^ig/L 

Ce fAg/L 

Pr |Ag/L 

Nd |Ag/L 

Sm|Ag/L

Tb|Ag/L 

Gd|Ag/L

Ho|Ag/L

Er|Ag/L

Tm|Ag/L

Yb^g/L 

Hf^g/L

Ta|ig/L

w^g/L

Re ^g/L 

Au fAg/L

^n^g/L 

Bi^g/L 

Th^g/L

34.0

0.63

2.2

13

52

0.2

14

0.04

0.04

0.5

0.5

3.3

54

1.3

0.05

<0.02

0.1

<0.01

<0.01

1

0.2

<0.01

50

1.7

3.8

0.51

2.1

0.37

0.056

0.050

0.36

0.26

0.05

0.14

0.02

0.1

<0.05

<0.02

0.06

<0.02

0.02

<0.05

0.02

0.57

0.05

0.420

0.3

1.8

2

40

0.08

0.4

<0.02

<0.02

<0.2

0.3

1.5

57

0.3

<0.05

<0.02

0.08

<0.01

<0.01

<0.05

0.07

<0.01

31

0.3

0.58

0.08

0.33

0.06

0.01

0.008

0.060

0.050

0.007

0.03

< 0.005

0.03

<0.05

<0.02

0.02

<0.02

<0.01

<0.05

<0.01

0.04

0.03

0.620

0.3

0.8

2

5

0.03

0.61

0.02

<0.02

<0.2

0.4

1.2

40

0.54

0.06

<0.02

0.08

< 0.01

<0.01

<0.05

0.06

<0.01

24

0.62

1.2

0.2

0.61

0.1

0.03

0.02

0.12

0.097

0.02

0.050

0.008

0.06

<0.05

<0.02

0.09

<0.02

<0.01

<0.05

<0.01

0.07

0.06

7.100

5.6

3.8

1

20

0.04

0.76

0.03

0.02

2

0.3

1.6

170

0.76

0.07

0.02

0.4

<0.01

<0.01

<0.05

0.04

<0.01

32

0.81

2.1

0.20

0.81

0.2

0.03

0.02

0.16

0.13

0.03

0.070

0.01

0.06

<0.05

<0.02

0.05

<0.02

0.07

<0.05

<0.01

0.20

0.14

19