Using pilot trials to test geochemical treatment of acid mine drainage on Stockton Plateau

Coal mine drainage chemistry on the West Coast of the South Island is highly variable; pH ranges from about 2Á8, and chemical concentrations vary by several orders of magnitude. Factors that influence mine drainage chemistry on the West Coast include regional geology, mine type, hydrogeology, and local geology. At a regional scale, mine drainage chemistry is bimodal and relates to geological formations. Mines within the Paparoa Coal Measures have neutral mine drainage, whereas those within the Brunner Coal Measures have acid mine drainage. This is related to the availability of SO 4 during coal measures deposition and, in combination with Fe and organic material, the subsequent formation of pyrite during burial. Paparoa Coal Measures were deposited in alluvial to lucustrine environments where SO 4 was relatively unavailable, whereas Brunner Coal Measures were deposited in alluvial to estuarine to marginal marine settings where marine SO 4 was abundant. Brunner Coal Measures acid mine drainage chemistry is influenced by mine type; open cast mines have Al-and trace element-rich acid mine drainage compared to underground mines. Acid mine drainage forming reactions that release trace elements and Al proceed more rapidly and completely at open cast mines where mine waste has a higher reactive surface area compared to waste rock at underground mines. Brunner coal mine drainage chemistry is also influenced by hydrogeology where flooded underground mines release less acid than free-draining mines because there is less oxygen available to react with pyrite. In addition, local geology overprints mine drainage chemistry where differences in acid mine drainage chemistry arise from changes in contributing lithologies either within a single mine or between different coalfields. Identification of factors that control mine drainage chemistry enables prediction of mine drainage chemistry. These predictions have application to the mining industry for managing, mitigating, monitoring, and remediation of mine drainages that would otherwise cause negative environmental impact.

Section: Amd Chemistrymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Factors that influence coal mine drainage chemistry West Coast, South Island, New Zealand

Pope

Newman²,

Craw

et al. 2010

“…Trumm et al (2005Trumm et al ( , 20082010) summarised AMD chemistry and results from shortterm mesocosm field studies for remediating AMD from Sullivan Mine, an abandoned underground coal mine within the Brunner Coal Measures, other sites at Stockton Coal Mine, and in the Pike River area. In general, results of this study showed comparable or better metal removal rates and efficiencies to those presented by Trumm et al (2005Trumm et al ( , 20082010) and others (e.g. Gusek 2002;Gusek & Wildeman 2002;Rose & Dietz 2002;Thomas & Romanek 2002b;Gusek 2004;Watzlaf et al 2004;Reisman et al 2008).…”

Section: Variability Of Stockton Coal Mine Drainage Chemistry 219mentioning

confidence: 99%

Variability of Stockton Coal Mine drainage chemistry and its treatment potential with biogeochemical reactors

McCauley¹,

O’Sullivan²,

Weber³

et al. 2010

Thirteen acid mine drainage seeps emanating from waste rock dumps and associated sediment ponds were monitored at Stockton Coal Mine near Westport, New Zealand to identify and quantify metal loads and delineate their spatial and temporal variability. Dissolved metal concentrations ranged from 0.05Á1430 mg/L Fe, 0.200Á627 mg/L Al, 0.0024Á0.594 mg/L Cu, 0.0052Á4.21 mg/L Ni, 0.019Á18.8 mg/L Zn, B0.00005Á0.0232 mg/L Cd, 0.0007Á0.0028 mg/L Pb, B0.001Á0.154 mg/L As and 0.103Á29.3 mg/L Mn and the pH ranged from 2.04Á4.31. Currently this acid mine drainage is treated further downstream by a number of water treatment plants employing a combination of ultra fine limestone and Ca(OH) 2 . However, in the interest of assessing more cost-effective technologies, biogeochemical reactors were assessed in the laboratory as potential cost-effective passive treatment options. Results of mesocosm-scale treatability tests showed that biogeochemical reactors incorporating mussel shells, pine bark, wood fragments (post peel) and compost increased pH to 6.7 and sequestered ]98.2% of the metal load from the Manchester Seep located within the Mangatini Catchment. Laboratory results demonstrated that the maximum loading rate was 0.8 mol total metals/m 3 substrate, and an average of 20.0 kg/day (7.30 tonnes/year) of metals could be removed by appropriately sized biogeochemical reactors.

“…Alarcon 1997;Lindsay et al 2003;Hughes et al 2004;Black et al 2005;Pope et al 2010), few studies have focused on treatment Weber et al 2007;Trumm et al 2008;Weber et al 2008;McCauley et al 2010). Neutralisation of AMD can be accomplished by either active or passive treatment systems.…”

Section: Introductionmentioning

confidence: 99%

Results of small-scale passive system trials to treat acid mine drainage, West Coast Region, South Island, New Zealand

Trumm¹,

Watts²

2010

Successful passive treatment of acid mine drainage can be improved through the use of small-scale pilot treatment systems to confirm appropriate system selection. Small-scale reducing and alkalinity producing systems were tested at two acid mine drainage sites in the West Coast Region, South Island, New Zealand: the Sullivan Mine and the Pike River Adit. A laboratory trial consisting of a limestone leaching column was conducted on the Blackball Mine acid mine drainage, West Coast Region. All three sites contain low pH (Sullivan Mine, 2.9; Pike River Adit, 3.2; Blackball Mine, 3.1), elevated Fe (Sullivan Mine, 47 mg/ L; Pike River Adit, 34 mg/L; Blackball Mine, 10.6 mg/L), elevated Al (Sullivan Mine, 14 mg/L; Pike River Adit, 1.6 mg/L; Blackball Mine, 14.1 mg/L) and minor concentrations of Mn (0.35Á0.51 mg/L), Ni (0.005Á0.13 mg/L) and Zn (0.14Á1.1 mg/L). The percentages of metals removed by the Sullivan Mine reducing and alkalinity producing system were: Fe (97%), Al (100%) and Ni (66%). The percentage metal removals at the Pike River Adit reducing and alkalinity producing system were: Fe (99%), Al (96%), Ni (95%) and Zn (99%). Percent metal removals for the Blackball Mine acid mine drainage were: Fe (87%), Al (91%), Mn (21%) and Zn (68%). Interpretation of data from these small-scale systems suggests that a reducing strategy may be successful at the Sullivan Mine and Pike River Adit and that an oxidising strategy may be appropriate for the Blackball Mine.