Refinement of Adti-Wp2 Standard Weathering Procedures, and Evaluation of Particle Size and Surface Area Effects Upon Leaching Rates: Part 1: Laboratory Evaluation of Method Performance

Hornberger, Roger J.; Brady, Keith B.C.; Cuddeback, Joan; White, William Β.; Scheetz, Barry E.; Telliard, William A.; Parsons, Stephen C.; Loop, Caroline M.; Bergstresser, Timothy W.; McCracken, Carlton R.; Wood, Duane

doi:10.21000/jasmr04010916

Cited by 6 publications

(5 citation statements)

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“…The status and results of this project are discussed in detail in Hornberger et al, (2004) presented at this meeting Selenium Selenium is a naturally occurring widely distributed element, which shows an affinity for sulfide minerals. It combines with metals and non-metals and may form both organic and inorganic compounds.…”

Section: Kinetic Test Methodsmentioning

confidence: 99%

Acid Drainage Technology Initiative: Continuing Progress in Coal Related Topics

Parsons¹,

Ziemkiewicz²

2004

ASMR

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Abstract. In 1995, the U.S. Office of Surface Mining (OSM) and the National Mine Land Reclamation Center (NMLRC) joined with the Interstate Mining Compact Commission, the National Mining Association, academia, and other Federal agencies to form the Acid Drainage Technology Initiative (ADTI). The ADTI partnership seeks to identify, evaluate and develop "best science" based practices to prevent new acid mine drainage sources and eliminate existing sources. The ADTI partnership developed a management structure to oversee the program and developed action plans to address key technical areas. The ADTI organization consists of a coal mining sector, a metal mining sector and a secretariat, overseen by an Operations Committee. The coal mining sector of ADTI is divided into a prediction working group and an avoidance and remediation working group to implement and coordinate the research strategy. This paper summarizes the results of the coal mining sector efforts since the completion of the avoidance and remediation, and prediction handbooks in 1998 and 2000, respectively, and the status of current activities. The activities have included field verification of acid drainage predictions using acid-base accounting, monitoring and follow up evaluation of acid mine drainage passive and in-situ treatment systems, developing standardized kinetic testing protocols, flooded underground mine pools, and issues related to elevated selenium in streams associated with surface mines.Additional Key Words: acid mine drainage, coal mining sector.

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Section: Kinetic Test Methodsmentioning

confidence: 99%

Acid Drainage Technology Initiative: Continuing Progress in Coal Related Topics

Parsons¹,

Ziemkiewicz²

2004

ASMR

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“…Further details are provided in Hornberger et al (2004). The addition of a CO 2 enriched atmosphere is a major departure from many other simulated weathering test methods.…”

Section: Total 100mentioning

confidence: 99%

“…Initial development in phases I and II included evaluation of different test apparatus, effects of particle size, gas composition, leaching frequency and other variables. Phases I and II results are reported by Brady et al (2004) and Hornberger et al (2004). In Phase III, a standard column leaching protocol was used by eight commercial, government and university labs to test five rocks of different lithology, pyrite and carbonate content.…”

Section: Introductionmentioning

confidence: 99%

Standard Weathering Procedure for Coal Overburden, Inter-Laboratory Study of Leachate Composition

Perry¹,

Cuddeback²,

Brady³

et al. 2008

ASMR

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Abstract. Simulated weathering tests are used to estimate leachate quality from rocks containing varying concentrations of pyrite and carbonates at mines. Five rock samples of coal overburden materials were subjected to a standardized column leaching test at eight commercial, university and government laboratories. Splits from sized, homogenized bulk samples were loaded in duplicate columns, incubated under humid air containing 10% CO 2 , and leached every 7 days for a 14 week period. Leachates were analyzed for mine drainage parameters including acidity, alkalinity, metals, sulfate and selected trace elements.Relative percent difference (RPD) and relative standard deviation (RSD) statistics show the variation within individual labs and among the group of labs. Fe, Al, Se, Zn and Acidity exhibited the greatest variability in results across all rock samples and labs. RPD's usually exceeded 30% for these parameters. The variation in Fe and Acidity increased with weathering duration. Ca, Mg, Na, SO 4, and specific conductance were the most consistent parameters. Mass weighting the chemical concentrations to account for differences in sample mass and leachate volumes did not noticeably improve the RPD and RSD statistics. Cumulative quantities leached were, however, consistent among labs for most parameters.About 2 to 6 % of the total sulfur present in the rocks was leached during the test. One rock sample was near saturation for gypsum, and some sulfate may have been retained in the column. Acid neutralizing capacity was depleted at a faster rate than acid producing potential. Carbonate dissolution varied, with 3 of 5 rocks producing solutions that were saturated for calcite, while two rocks produced under-saturated solutions. Four of five rocks had less than 5 % of total Ca and Mg leached, with similar or smaller leaching fractions for other elements. More than 90% of the iron mobilized by pyrite weathering was retained in the column for all samples. One acid forming sample leached elements more aggressively than the rocks producing neutral leachates.The inter-lab results show that the standard column test can yield consistent estimates of mine water composition, and differentiate the behavior of various rock and mineral assemblages. __________________

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“…Laboratory-scale column and mesocosm-scale lysimeter experiments have been used to predict TDS release from coal industry materials (overburden, refuse, combustion byproducts) for nearly three decades (e.g., Brady et al, 1998;Clark et al, 2018;Daniels et al, 2014a;Daniels et al, 2016;Daniels et al, 2014b;Hornberger et al, 2004;Orndorff et al, 2015). These studies have shown that (1) rock type and extent of weathering influence TDS release, (2) shales and mudstones release more TDS than sandstones, and (3) unweathered rocks release more TDS than weathered materials.…”

Section: Introductionmentioning

confidence: 99%

Batch extraction method to estimate total dissolved solids (TDS) release from coal refuse and overburden

Castillo-Meza

Cravotta

Tasker

et al. 2020

Applied Geochemistry

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A rapid batch extraction method was evaluated to estimate potential for total dissolved solids (TDS) release by 65 samples of rock from coal and gas-bearing strata of the Appalachian Basin in eastern USA. Three different extractant solutions were considered: deionized water (DI), DI equilibrated with 10% CO 2 atmosphere (DI þ CO 2 ), or 30% H 2 O 2 under 10% CO 2 (H 2 O 2 þCO 2 ). In all extractions, 10 g of pulverized rock (<0.5-mm) were mixed with 20 mL of extractant solution and shaken for 4 h at 50 rpm and 20-22 � C. The 65 rock samples were classified as coal (n¼3), overburden (n ¼ 17), coal refuse that had weathered in the field (n ¼ 14), unleached coal refuse that had oxidized during indoor storage (n ¼ 20), gas-bearing shale (n ¼ 10), and pyrite (n ¼ 1). Extracts were analyzed for specific conductance (SC), TDS, pH, and major and trace elements, and subsequently speciated to determine ionic contributions to SC. The pH of extractant blanks decreased in the order DI (6.0), DI þ CO 2 (5.1), and H 2 O 2 þCO 2 (2.6). The DI extractant was effective for mobilizing soluble SO 4 and Cl salts. The DI þ CO 2 extractant increased weathering of carbonates and resulted in equivalent or greater TDS than the DI leach of the same material. The H 2 O 2 þCO 2 extractant increased weathering of sulfides (and carbonates) and resulted in the greatest TDS production and lowest pH values. Of the 65 samples, 19 had leachate chemistry data from previous column experiments and 35 were paired to 10 field sites with leachate chemistry data. When accounting for the water-to-rock ratio, TDS from DI and DI þ CO 2 extractions were correlated to TDS from column experiments while TDS from H 2 O 2 þCO 2 extractions was not. In contrast to column experiments, field SC was better correlated to SC measured from H 2 O 2 þCO 2 extractions than DI extractions. The field SC and SC from H 2 O 2 þCO 2 extractions were statistically indistinguishable for 7 of 9 paired data sets while SC from DI extractions underestimated field SC in 5 of 9 cases. Upscaling comparisons suggest that (1) weathering reactions in the field are more aggressive than DI water or synthetic rainwater extractants used in batch or column tests, and (2) a batch extraction method utilizing 30% H 2 O 2 (which is mildly acidic without CO 2 enrichment) could be effective for identifying rocks that will release high amounts of TDS.

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Refinement of Adti-Wp2 Standard Weathering Procedures, and Evaluation of Particle Size and Surface Area Effects Upon Leaching Rates: Part 1: Laboratory Evaluation of Method Performance

Cited by 6 publications

References 5 publications

Acid Drainage Technology Initiative: Continuing Progress in Coal Related Topics

Acid Drainage Technology Initiative: Continuing Progress in Coal Related Topics

Standard Weathering Procedure for Coal Overburden, Inter-Laboratory Study of Leachate Composition

Batch extraction method to estimate total dissolved solids (TDS) release from coal refuse and overburden

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