Geochemical characterization of drainage prior to reclamation at the abandoned Valzinco Mine, Spotsylvania County, Virginia

Seal, Robert R.; Johnson, Adam N.; Hammarstrom, Jane M.; Meier, Allen L.

doi:10.3133/ofr02360

Cited by 6 publications

(4 citation statements)

References 4 publications

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“…Geochemical analyses included the measurement of unstable parameters on site and laboratory analysis of major, minor, and trace constituents following the procedures described by Seal et al (2002). Unstable parameters included water temperature, pH, specific conductance, and dissolved concentrations of O 2 , Fe 2+ , and total Fe.…”

Section: Methodsmentioning

confidence: 99%

“…Measured discharges at site VLZN-3 ranged widely from 4.8 to 113 L/s (Seal et al, 2002). On an annual basis, discharges tend to be highest in the late winter or early spring, and lowest in the late summer or early fall.…”

Section: Hydrologic and Climatic Settingmentioning

confidence: 99%

“…Water-quality data in the vicinity of the Valzinco mine before reclamation has been presented and discussed by Seal et al (2002) and Seal et al (2008). Prior to reclamation, the pH of Knight's Branch upstream of the site ranged between 4.4 and 6.1 (Figs.…”

Section: Before Reclamationmentioning

confidence: 99%

“…The first post-reclamation sampling was done a few months after the completion of remediation construction, the second approximately ten months later, and the last five years after the first post-reclamation sampling. Pre-reclamation characterization of the water quality and mine waste has been presented by Seal et al (2002) and Hammarstrom et al (2006), respectively. Seal et al (2008) described processes controlling the generation of acid drainage and the associated mobility of metals.…”

Section: Introductionmentioning

confidence: 99%

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WATER QUALITY BEFORE AND AFTER RECLAMATION AT THE ABANDONED VALZINCO Zn-Pb MINE SITE, SPOTSYLVANIA COUNTY, VIRGINIA

Seal¹,

Hammarstrom²,

Bishop³

et al. 2008

JASMR

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The Valzinco deposit was a massive sulfide ore body, dominated by pyrite, sphalerite, galena, and chalcopyrite. It was mined intermittently in the first half of the 20th century by underground methods. The host rocks were metamorphosed felsic volcanic rocks. Mine wastes were dominated by flotation tailings deposited in the stream channel, which were subsequently partially transported downstream by fluvial processes. Acid-base accounting results indicate that the tailings are net acid (net neutralizing potential =-268 to-138 kg CaCO 3 /tonne) and leach significant quantities of Fe, Al, Zn, Pb, Cu, Cd, and SO 4 2-. Pre-reclamation quarterly sampling of the stream below the site documented low-pH waters having elevated concentrations of Fe, Al, Zn, Pb, Cu, Cd, and SO 4 2-. Reclamation began in 2001 and major construction was completed in 2002. Reclamation included the removal and encapsulation on site of tailings, application of bactericide, installation of limestone drains, construction of wetlands, and revegetation. Results of recent sampling of the site (June 2007) indicate an increase in pH from 3.4 to 5.1, an increase in hardness of 37 %, and decreases in total dissolved solids (68 %), Fe (94 %), Al (98 %), Zn (77 %), Pb (99.5 %), Cu (97 %), Cd (94 %), and SO 4 2-(81 %) relative to mean prereclamation values. Even though significant reductions in dissolved metals have been achieved and positive biologic indicators of ecosystem health are present, the concentrations of Cu and Zn remain above hardness-based acute ecosystem toxicity criteria. The elevated concentrations, in part, appear to be a natural, premining characteristic of the watershed. The elevated concentrations also highlight the sensitivity of calculated hardness-based toxicity criteria for soft waters. The hardness-based criteria do not account for the mitigating effect of dissolved organic carbon on metal toxicity in wetland areas such as at Valzinco.

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Section: Methodsmentioning

confidence: 99%

Section: Hydrologic and Climatic Settingmentioning

confidence: 99%