An Injection Technique for/N-S/Turemediation of Abandoned Underground Coal Mines

Canty, Geoffrey A.; Everett, John W.

doi:10.21000/jasmr98010690

Cited by 6 publications

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“…The slurry was injected in alternating densities (0, 10 and 12 lb ash/gallon slurry) in order to maximize the movement of the material and to promote the creation of the "buffered zone". For a more thorough discussion of the process, refer to Canty and Everett (1998).…”

Section: Methodsmentioning

confidence: 99%

Acid Mine Drainage Treatment via Alkaline Injection Technology

Canty¹,

Everett²

2002

JASMR

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Abstract. The Oklahoma Conservation Commission conducted a demonstration project to investigate the feasibility of treating acid mine drainage by chemically altering the characteristics of the mine water. The treatment method involved the injection of an alkaline coal combustion byproduct directly into a flooded underground mine. The project was based on the premise that the alkaline materials in the ash would create an in-situ chemical condition that would result in acid neutralization, metal precipitation, and would impart alkalinity to the mine drainage. Alkaline injection technology (AIT) was successful at raising pH and alkalinity, while reducing acidity and metals loading, but the duration of the treatment and the environmental significance was temporary. After 15 months, the water quality characteristics appeared to approach pre-injection conditions. However, after reviewing the water quality data from the past 4 years there are statistically significant reductions in acidity (23%), iron (18%), and aluminum (47%), and an increase in pH (0.35 units). Presumably, the mine environment has reached equilibrium with the alkalinity introduced to the system. A second study is currently underway to determine if the total amount of alkalinity was actually limited in the system or if there are other factors involved that limit the effectiveness of AIT.

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Section: Methodsmentioning

confidence: 99%

Acid Mine Drainage Treatment via Alkaline Injection Technology

Canty¹,

Everett²

2002

JASMR

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“…As discussed previously (Canty and Everett, 1998a), the concept of injecting CCBs into a mine is not necessarily new; other studies have been conducted using a variety of CCBs. In most instances, CCB grouts and slurries were injected to fill mine voids to prevent the formation or acidic mine drainage or to seal off acid-generating areas.…”

Section: Alkaline Injection Technology Conceptmentioning

confidence: 99%

“…Chemical Theory (The chemical concept involved with AIT was initially presented in Everett 1998a andupdated in Canty andEverett, 2002. The following paragraphs were adapted or taken directly from these papers.…”

Section: Alkaline Injection Technology Conceptmentioning

confidence: 99%

“…Field demonstration began in July 1997 with initial positive results (Canty and Everett, 2002;Canty and Everett, 1999;Canty and Everett, 1998a;and Canty and Everett, 2002). However, the amount of alkalinity added to the system appeared to be insufficient and resulted in finite treatment; that is, noteworthy water quality improvements were observed for only 15 months.…”

Section: Introductionmentioning

confidence: 99%

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The Use of Coal Combustion by-Products for in Situ Treatment of Acid Mine Drainage

Canty¹,

Everett²

2004

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In 1994 a demonstration project was undertaken to investigate the effectiveness of using CCBs for the in situ treatment of acidic mine water. Actual injection of alkaline material was performed in 1997 with initial positive results; however, the amount of alkalinity added to the system was limited and resulted in short duration treatment. In 1999, a CBRC grant was awarded to further investigate the effectiveness of alkaline injection technology (AIT). Funds were released in fall 2001. In December 2001, 2500 tons of fluidized bed combustion (FBC) ash were injected into the wells used in the 1997 injection project.Post injection monitoring continued for 24 months. During this period the mine chemistry had gone through a series of chemical changes that manifested as stages or "treatment phases." The mine system appeared to be in the midst of reestablishing equilibrium with the partial pressure of mine headspace. Alkalinity and pH appeared to be gradually increasing during this transition. As of December 2003, the pH and alkalinity were roughly 7.3 and 65 ppm, respectively. Metal concentrations were significantly lower than pre-injection levels, but iron and manganese concentrations appeared to be gradually increasing (roughly 30 ppm and 1.25 ppm, respectively). Aluminum, nickel, and zinc were less than pre-injection concentrations and did not appear to be increasing (roughly

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“…In general, the utility of AMD treatment using CCPs has been examined by injecting grouts into underground mines ( e.g., Canty and Everett, 1998). However, they have not been used as an alkalinity source in passive treatment systems.…”

Section: Introductionmentioning

confidence: 99%

Alkalinity Generation and Metals Retention in Vertical-Flow Treatment Wetlands

Nairn¹,

Mercer²,

Lipe³

2000

ASMR

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Designs of constructed wetlands for acid mine drainage (AMD) treatment have evolved substantially during the past decade. Current research focuses on the study of vertical-flow treatment systems containing labile organic substrates and limestone. Also known as successive alkalinity producing systems (SAPS), these systems emphasize contact of acidic waters with the substrate, thus maximizing biological alkalinity generation via bacterial sulfate reduction, and abiotic alkalinity generation via carbonate dissolution. In this study, alkalinity generation and metals retention were evaluated during the initial year of operation for a modified successive alkalinity producing system (SAPS). The system consists of four l 85-m 2 in-series cells comprised of alternating vertical-flow anaerobic substrate wetlands (VFs) and surface-flow aerobic settling ponds (SFs). The substrate in the VFs consists of spent mushroom substrate (SMS) and limestone gravel (LS), supplemented with hydrated fly ash (HFA) in a 2: I :0.1 ratio by volume. Approximately 15±4.4 L/min of acid mine drainage (AMD) from an abandoned underground mine in southeastern Oklahoma was directed to the pilot-scale treatment system in October 1998. Mean influent water quality was characterized as follows: 660 mg L-1 net acidity as CaC0 3 eq., pH 3.4, 215 mg L-1 total Fe, 36 mg L-1 Al, 14 mg L-1 Mn, and 1000 mg L-1 so,-2 • Flow through the first vertical-flow wetland cell (VF!) resulted in substantial alkalinity increases, metal concentration decreases and circumneutral pH (6.33±0.34). Alkalinity was produced in VF! by a combination of processes, including LS and HFA dissolution and bacterial sulfate reduction (BSR), to 258±84 mg L-1• Adequate alkalinity was added to the AMD in the VF cells so that final discharge waters were net alkaline on all sampling dates (mean net alkalinity -136 mg L-1 ). Total Fe and Al concentrations decreased significantly in VF! from 216±45 to 44±28 mg L-1 and 36±6.9 to 1.29±4.4 mg L-1 , respectively (p<0.05). Approximately 600 kg of iron and 120 kg of aluminum were retained in VF!. Sequential extractions of VF! substrate samples fractionated metals by form (water-soluble, exchangeable, organically-bound, carbonate, oxide or oxide-bound or residual). Manganese concentrations did not change significantly in the first two cells, but decreased significantly (p<0.05) in the second two cells (from 15.41±3.26 to 5.69±0.91 mg L-1 ). Mean acidity removal rates in VF! (51 g m-2 daf 1 ) were considerably higher than previously reported values. Sustainable acidity removal rates of this magnitude would result in design criteria leading to considerable savings in system construction and land acquisition costs.

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An Injection Technique for/N-S/Turemediation of Abandoned Underground Coal Mines

Cited by 6 publications

References 0 publications

Acid Mine Drainage Treatment via Alkaline Injection Technology

Acid Mine Drainage Treatment via Alkaline Injection Technology

The Use of Coal Combustion by-Products for in Situ Treatment of Acid Mine Drainage

Alkalinity Generation and Metals Retention in Vertical-Flow Treatment Wetlands

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