Geochemical effects of oxidation products and framboidal pyrite oxidation in acid mine drainage prediction techniques

Weber, P.A.; Stewart, Warwick A.; Skinner, William; Weisener, Christopher G.; Thomas, Joan E.; Smart, Roger St. C.

doi:10.1016/j.apgeochem.2004.05.002

Cited by 85 publications

(49 citation statements)

References 25 publications

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“…This conversion factor is determined from the stoichiometry of the pyrite oxidation (Equation 1). Further details of these tests have been reported previously (IWRI and EGi, 2002;Weber et al, 2004). Results are presented in Table 1.…”

Section: Net Acid Production Potentialmentioning

confidence: 92%

“…Argon purged leach test To determine the readily available soluble sulfate acidity (SA) present in the sample due to oxidation of pyrite, an argon purged deionized water leach (Weber et al, 2004) was conducted on samples that had paste pH values < pH 7.0. It is assumed that minimal O 2 -induced pyrite oxidation would occur under these conditions (e.g., Equation 1), and likewise, minimal pyrite oxidation by Fe +3 would occur due to the circum-neutral pH values and the lack of O 2 that is needed as a terminal electron acceptor.…”

Section: Net Acid Production Potentialmentioning

confidence: 99%

“…Cruywagen et al (2003) stated that samples with a pH < 4.0 are classified as acid/toxic regardless of their overall NAPP or NAG characteristics as acid drainage will be immediately generated. Weber et al (2004) suggested that samples with paste pH values of < pH 5 would contain acidic SO 4 -2 salts, which would release acidity during the ANC test thereby obscuring part of the acid neutralization capacity of the sample and biasing the NAPP calculation towards positive NAPP values (e.g., classification of the sample as potentially-acid-forming).…”

Section: Introductionmentioning

confidence: 99%

“…This paper investigates acid-base accounting (ABA) data for six rock samples that were characterized as part of the Australian Minerals Industry Research Association (AMIRA) P387a project: Prediction and Kinetic Control of Acid Mine Drainage (e.g., IWRI and EGi, 2002;Weber et al, 2004;Weber et al 2005a,b); two rock samples were also assessed as part of research allied to the AMIRA P387b project: Neutralizing Mineral Reactions in Acid Mine Drainage Control (Weber, 2003); and 31 samples that were assessed as part of research projects funded by Solid Energy (NZ) Ltd (SENZ) that included work by Hughes (2004) and Connor (2005). One prerequisite for sample acceptance into this test suite was that it contained negligible quantities of sulfides other than pyrite.…”

Section: Introductionmentioning

confidence: 99%

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SHORT-TERM ACID ROCK DRAINAGE CHARACTERISTICS DETERMINED BY PASTE pH AND KINETIC NAG TESTING: CYPRESS PROSPECT, NEW ZEALAND

Weber¹,

Hughes²,

Conner³

et al. 2006

JASMR

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Abstract. The paste pH test (1 part solid: 2 parts water) is one method used to determine the acidic nature of a rock/soil sample. In conjunction with kinetic NAG testing a classification scheme has been developed for the Cypress Prospect within the Stockton coal mining region, West Coast, New Zealand. Samples having a paste pH of < 4.0 are considered potentially acid forming (PAF) and contain significant acidic sulfate salts (up to 30.1 kg H 2 SO 4 /t equivalent) that will immediately produce acid upon exposure to water. Samples with a paste pH of 4.0 -5.0 are considered PAF, but have a lower stored acidic salt content (up to 9.0 kg H 2 SO 4 /t equivalent). In the field the lithologies represented by both these rock types are likely to generate ARD immediately upon exposure to water. Circum-neutral paste pH values (> pH 5.0) for samples classified PAF indicated that they have a short-term acid neutralization capacity (ANC) that is greater than the readily available short-term acid generating capacity of the sample. This resulted in a time lag (2 -356 minutes) prior to decrease to pH 4 in the kinetic NAG test. Samples having a paste pH > 6.0 typically produced a longer lag period than those with a paste pH of 5 -6. As previous researchers have demonstrated this represents a lag period prior to the onset of laboratory acid rock drainage in larger column leach tests. These results have direct application to strategic mine planning at the proposed Cypress mine including separating waste rock into immediate acid generators (high management priority) from acid generators with a lag to acid formation (lower priority) and non-acid forming. Field validation of this classification system is still needed.

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Section: Net Acid Production Potentialmentioning

confidence: 92%

Section: Net Acid Production Potentialmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

SHORT-TERM ACID ROCK DRAINAGE CHARACTERISTICS DETERMINED BY PASTE pH AND KINETIC NAG TESTING: CYPRESS PROSPECT, NEW ZEALAND

Weber¹,

Hughes²,

Conner³

et al. 2006

JASMR

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“…The MAP value (in kg CaCO 3 /t) was calculated according to the formula proposed by Sobek et al (1978): MAP = S (wt%) × 31.25. This calculation assumes that all S is contained in pyrite, which is a reasonable approximation (Sobek et al 1978;Weber et al 2004Hughes et al 2007). …”

Section: Standard Acid-base Accountingmentioning

confidence: 99%

Prediction of acid mine drainage generation potential of various lithologies using static tests: Etili coal mine (NW Turkey) as a case study

Yücel

Baba

2016

Environ Monit Assess

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The Etili neighborhood in Can County (northwestern Turkey) has large reserves of coal and has been the site of many small-to medium-scale mining operations since the 1980s. Some of these have ceased working while others continue to operate. Once activities cease, the mining facilities and fields are usually abandoned without rehabilitation. The most significant environmental problem is acid mine drainage (AMD). This study was carried out to determine the acid generation potential of various lithological units in the Etili coal mine using static test methods. Seventeen samples were selected from areas with high acidic water concentrations: from different alteration zones belonging to volcanic rocks, from sedimentary rocks, and from coals and mine wastes. Static tests (paste pH, standard acid-base accounting, and net acid generation tests) were performed on these samples. The consistency of the static test results showed that oxidation of sulfide minerals, especially pyrite-which is widely found not only in the alteration zones of volcanic rocks but also in the coals and mine wastes-is the main factor controlling the generation of AMD in this mine. Lack of carbonate minerals in the region also increases the occurrence of AMD.

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Functionalization of microcapsules for the removal of heavy metal ions

Sánchez-Silva

Alcázar

Lucas

et al. 2010

J of Chemical Tech & Biotech

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BACKGROUND: Solvent extraction and ion exchange technologies have been widely used for the recovery or removal of heavy metals from aqueous phases. However, different problems have been encountered on applying these techniques. Although the extractants are highly selective, this technique requires a high level of mechanical agitation to improve the kinetics of the process, a requirement that promotes leakage of the extractant from the aqueous/organic interface to the aqueous phase during separation of the two phases. On the other hand, ion exchangers can easily be regenerated but gel form resins have low selectivity and those with high selectivity (chelating resins) have low diffusion coefficients, a characteristic that leads to low mass transfer rates. An interesting alternative to overcome these limitations is the microencapsulation of extractants within a functionalized polymeric shell. This new type of material would be expected to combine the advantages of the aforementioned methods and improve selective removal of heavy metals from an aqueous phase.

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Geochemical effects of oxidation products and framboidal pyrite oxidation in acid mine drainage prediction techniques

Cited by 85 publications

References 25 publications

SHORT-TERM ACID ROCK DRAINAGE CHARACTERISTICS DETERMINED BY PASTE pH AND KINETIC NAG TESTING: CYPRESS PROSPECT, NEW ZEALAND

SHORT-TERM ACID ROCK DRAINAGE CHARACTERISTICS DETERMINED BY PASTE pH AND KINETIC NAG TESTING: CYPRESS PROSPECT, NEW ZEALAND

Prediction of acid mine drainage generation potential of various lithologies using static tests: Etili coal mine (NW Turkey) as a case study

Functionalization of microcapsules for the removal of heavy metal ions

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