Identification and Treatment of Potential Acid-Producing Rocks and Water Quality Monitoring Along a Transmission Line in the Blue Ridge Province, Southwestern North Carolina

Schaeffer, Malcolm F.; Clawson, Phyllis A.

doi:10.2113/gseegeosci.ii.1.35

Cited by 9 publications

(6 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Landslides are common in this lithology (Schultz, 1998), creating temporary, but catastrophic, impacts on aquatic ecosystems. The lithology also poses engineering problems because of the high potential for acid generation associated with exposing fresh pyrite-bearing rock surfaces during construction projects (Tingle, 1995;Byerly, 1996;Schaeffer and Clawson, 1996). Efflorescent sulfate salts coat freshly exposed outcrops in landslide breakaway zones.…”

Section: Great Smoky Mountainsmentioning

confidence: 99%

Secondary sulfate minerals associated with acid drainage in the eastern US: recycling of metals and acidity in surficial environments

et al. 2005

View full text Add to dashboard Cite

Weathering of metal-sulfide minerals produces suites of variably soluble efflorescent sulfate salts at a number of localities in the eastern United States. The salts, which are present on mine wastes, tailings piles, and outcrops, include minerals that incorporate heavy metals in solid solution, primarily the highly soluble members of the melanterite, rozenite, epsomite, halotrichite, and copiapite groups. The minerals were identified by a combination of powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron-microprobe. Base-metal salts are rare at these localities, and Cu, Zn, and Co are commonly sequestered as solid solutions within Fe-and Fe-Al sulfate minerals. Salt dissolution affects the surfacewater chemistry at abandoned mines that exploited the massive sulfide deposits in the Vermont copper belt, the Mineral district of central Virginia, the Copper Basin (Ducktown) mining district of Tennessee, and where sulfide-bearing metamorphic rocks undisturbed by mining are exposed in Great Smoky Mountains National Park in North Carolina and Tennessee.Dissolution experiments on composite salt samples from three minesites and two outcrops of metamorphic rock showed that, in all cases, the pH of the leachates rapidly declined from 6.9 to b3.7, and specific conductance increased gradually over 24 h. Leachates analyzed after 24-h dissolution experiments indicated that all of the salts provided ready sources), and base metals (N1000 mg L À1 for minesites, and 2 mg L À1 for other sites). Geochemical modeling of surface waters, mine-waste leachates, and salt leachates using PHREEQC software predicted saturation in the observed ochre minerals, but significant concentration by evaporation would be needed to reach saturation in most of the sulfate salts. Periodic surface-water monitoring at Vermont minesites indicated peak annual metal loads during spring runoff. At the Virginia site, where no winter-long snowpack develops, metal loads were highest during summer months when salts were dissolved periodically by rainstorms following sustained evaporation during dry spells. areas, persist in protected areas when temperature and relative humidity are appropriate, and contribute to metal loadings and acidity in surface waters upon dissolution, thereby causing short-term perturbations in water quality. Published by Elsevier B.V.

show abstract

Section: Great Smoky Mountainsmentioning

confidence: 99%

Secondary sulfate minerals associated with acid drainage in the eastern US: recycling of metals and acidity in surficial environments

et al. 2005

View full text Add to dashboard Cite

show abstract

“…In this paper, the general term ''shale'' was used to refer to all of the finegrained, sulfidic metasiltstones, shales, slates, and schists in the study area (Anakeesta Formation, Wehutty Formation). The sulfidic rocks also pose engineering problems throughout the region for construction of roads, powerlines, and stream diversion because of their high potential for acid generation (Byerly 1994Tingle 1995;Schaeffer and Clawson 1996). Schultz (1998) documented the distribution of more than 25 Pleistocene to Recent debris flows within the Anakeesta Formation in the Mount LeConte area (Fig.…”

Section: Study Areamentioning

confidence: 99%

Weathering of sulfidic shale and copper mine waste: secondary minerals and metal cycling in Great Smoky Mountains National Park, Tennessee, and North Carolina, USA

et al. 2003

View full text Add to dashboard Cite

Metal cycling via physical and chemical weathering of discrete sources (copper mines) and regional (non-point) sources (sulfide-rich shale) is evaluated by examining the mineralogy and chemistry of weathering products in Great Smoky Mountains National Park, Tennessee, and North Carolina, USA. The elements in copper mine waste, secondary minerals, stream sediments, and waters that are most likely to have negative impacts on aquatic ecosystems are aluminum, copper, zinc, and arsenic because these elements locally exceed toxicity guidelines for surface waters or for stream sediments. Acid-mine drainage has not developed in streams draining inactive copper mines. Acid-rock drainage and chemical weathering processes that accompany debris flows or human disturbances of sulfidic rocks are comparable to processes that develop acid-mine drainage elsewhere. Despite the high rainfall in the mountain range, sheltered areas and intermittent dry spells provide local venues for development of secondary weathering products that can impact aquatic ecosystems.

show abstract

“…9a). A 1:1 ratio (acid/ base) is plotted and assumes that the tested samples that plot below this ratio are net acid consumers (e.g., Schoeffer and Clawson 1996). However, Lawrence and Scheske (1997) noted that different mineral groups have different relative reactivities (i.e., carbonate minerals react faster than feldspar minerals), and hence the control on neutralization varies with mineralogy and a more suitable value for the neutralizing potential is 0.54.…”

Section: Acid Generation Predictionmentioning

confidence: 99%

“…The production of acid and hence acid rock drainage (ARD) results from the oxidation of naturally occurring sulphide minerals in the rocks, and is a major issue facing development in the metropolitan portion of HRM. The environmental impacts associated with exposed or disturbed sulphide-rich rocks during routine construction activity (i.e., not related to metal or coal mining) are not unique to HRM and have been documented in many parts of the world (e.g., Piispanen and Nykyri, 1997;Morin et al 2003;Peng et al 2005;Schoeffer and Clawson 1996;Kwong et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Lithogeochemistry, petrology, and the acid-generating potential of the Goldenville and Halifax groups and associated granitoid rocks in the metropolitan Halifax Regional Municipality, Nova Scotia, Canada

White

Goodwin²

2011

atgeol

View full text Add to dashboard Cite

Detailed geological mapping of the Goldenville and Halifax groups in metropolitan Halifax Regional Municipality, Nova Scotia, resulted in two-fold subdivision of both groups. The Goldenville Group was divided into the metasandstone (feldspathic wacke)-dominated Taylors Head formation and the overlying, metasiltstone-dominated, Mn-rich Beaverbank formation. The Halifax Group was divided into the Cunard formation, dominated by sulphide-rich slate, and the overlying Bluestone formation, consisting of mainly metasiltstone and metasandstone. Lithogeochemical and petrological studies resulted in the characterization of the Beaverbank, Cunard, and Bluestone formations as potential acid-producing units with pyrrhotite as the main iron-sulphide mineral. The presence of acid rock drainage (ARD) is governed by bulk-rock chemical composition and mineral assemblage. To test the predictability of ARD production, a portable XRF instrument was used to obtain relatively inexpensive whole-rock and sulphur data that were used in conjunction with conventional XRF analyses and acid-base accounting tests. Results from the three methods compare favourably. Use of the portable XRF instrument facilitates a timely and cost-effective approach to predicting ARD but does not replace the legally mandated acid-base accounting procedure. RÉSUMÉUne cartographie géologique détaillée des groupes de Goldenville et de Halifax dans la municipalité régionale de Halifax, en Nouvelle-Écosse, a donné lieu à deux divisions de ces deux groupes. Pour ce qui est du groupe de Goldenville, les deux formations suivantes ont été établies: la Formation de Taylors Head, composée principalement de métagrès (wacke feldspathique) et la Formation de Beaverbank sus-jacente, composée principalement de métasiltite riche en Mn. En ce qui concerne le groupe de Halifax, les deux formations que voici ont été identifiées: la Formation de Cunard, composée principalement d'ardoise riche en sulfures, et la Formation de Bluestone sus-jacente, composée surtout de métasiltite et de métagrès. Les études lithogéochimiques et pétrologiques ont permis d'établir que les Formations de Beaverbank, de Cunard et de Bluestone étaient susceptibles d'agir comme précurseurs acides, la pyrrhotite étant le principal minéral à sulfure de fer présent. La présence d'un drainage rocheux acide (DRA) est régie par la composition chimique de la roche brute et l'association minérale. Pour vérifier la possibilité d'un DRA, de concert avec des analyses traditionnelles à fluorescence X et de bilan acide-base, un appareil portatif à fluorescence X a été utilisé pour recueillir de manière relativement économique des données sur la roche brute et les sulfures. Les résul-tats obtenus par les trois méthodes se comparent bien. L'utilisation d'un appareil à fluorescence X portatif permet de prédire de manière économique et rapidement la possibilité du DRA, mais cette technique ne saurait se substituer à l'analyse du bilan acide-base prévue par la réglementation.[Traduit par la redaction]

show abstract

Identification and Treatment of Potential Acid-Producing Rocks and Water Quality Monitoring Along a Transmission Line in the Blue Ridge Province, Southwestern North Carolina

Cited by 9 publications

References 0 publications

Secondary sulfate minerals associated with acid drainage in the eastern US: recycling of metals and acidity in surficial environments

Secondary sulfate minerals associated with acid drainage in the eastern US: recycling of metals and acidity in surficial environments

Weathering of sulfidic shale and copper mine waste: secondary minerals and metal cycling in Great Smoky Mountains National Park, Tennessee, and North Carolina, USA

Lithogeochemistry, petrology, and the acid-generating potential of the Goldenville and Halifax groups and associated granitoid rocks in the metropolitan Halifax Regional Municipality, Nova Scotia, Canada

Contact Info

Product

Resources

About