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Title: Site-specific study on stabilization of acid-generating mine tailings using coal fly ash

Abstract

A site-specific study on stabilizing acid-generating mine tailings from Sudbury Mine using a coal fly ash from Nanticoke Generating Station is presented in this paper. The objective of the study is to evaluate the feasibility of codisposal of the fly ash and mine tailings to reduce environmental impacts of Sudbury tailings disposal sites. The study includes three phases, i.e., characterization of the mine tailings, and coal fly ash, oxidation tests on the mine tailings and kinetic column permeation tests. The results of the experiments indicate that when permeated with acid mine drainage, the hydraulic conductivity of Nanticoke coal fly ash decreased more than three orders of magnitude (from 1 x 10{sup -6} to 1 x 10{sup -9} cm/s), mainly due to chemical reactions between the ash solids and acid mine drainage. Furthermore, the hydraulic gradient required for acid mine drainage to break through the coal fly ash is increased up to ten times (from 17 to 150) as compared with that for water. The results also show that the leachate from coal fly ash neutralizes the acidic pore fluid of mine tailings. The concentrations of trace elements in effluents from all kinetic column permeation tests indicated that coplacement of coalmore » fly ash with mine tailings has the benefit of immobilizing trace elements, especially heavy metals. All regulated element concentrations from effluent during testing are well below the leachate quality criteria set by the local regulatory authority.« less

Authors:
; ; ;  [1]
  1. University of Western Ontario, London, ON (Canada). Dept. of Civil & Environmental Engineering
Publication Date:
OSTI Identifier:
20741141
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Materials in Civil Engineering; Journal Volume: 18; Journal Issue: 2
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; TAILINGS; NICKEL ORES; MINING; FLY ASH; COAL; WASTE PRODUCT UTILIZATION; PH VALUE; DRAINAGE; OXIDATION; ACID MINE DRAINAGE; HYDRAULIC CONDUCTIVITY; CHEMICAL REACTIONS; TRACE AMOUNTS; ELEMENTS; LEACHATES

Citation Formats

Shang, J.Q., Wang, H.L., Kovac, V., and Fyfe, J. Site-specific study on stabilization of acid-generating mine tailings using coal fly ash. United States: N. p., 2006. Web. doi:10.1061/(ASCE)0899-1561(2006)18:2(140).
Shang, J.Q., Wang, H.L., Kovac, V., & Fyfe, J. Site-specific study on stabilization of acid-generating mine tailings using coal fly ash. United States. doi:10.1061/(ASCE)0899-1561(2006)18:2(140).
Shang, J.Q., Wang, H.L., Kovac, V., and Fyfe, J. Wed . "Site-specific study on stabilization of acid-generating mine tailings using coal fly ash". United States. doi:10.1061/(ASCE)0899-1561(2006)18:2(140).
@article{osti_20741141,
title = {Site-specific study on stabilization of acid-generating mine tailings using coal fly ash},
author = {Shang, J.Q. and Wang, H.L. and Kovac, V. and Fyfe, J.},
abstractNote = {A site-specific study on stabilizing acid-generating mine tailings from Sudbury Mine using a coal fly ash from Nanticoke Generating Station is presented in this paper. The objective of the study is to evaluate the feasibility of codisposal of the fly ash and mine tailings to reduce environmental impacts of Sudbury tailings disposal sites. The study includes three phases, i.e., characterization of the mine tailings, and coal fly ash, oxidation tests on the mine tailings and kinetic column permeation tests. The results of the experiments indicate that when permeated with acid mine drainage, the hydraulic conductivity of Nanticoke coal fly ash decreased more than three orders of magnitude (from 1 x 10{sup -6} to 1 x 10{sup -9} cm/s), mainly due to chemical reactions between the ash solids and acid mine drainage. Furthermore, the hydraulic gradient required for acid mine drainage to break through the coal fly ash is increased up to ten times (from 17 to 150) as compared with that for water. The results also show that the leachate from coal fly ash neutralizes the acidic pore fluid of mine tailings. The concentrations of trace elements in effluents from all kinetic column permeation tests indicated that coplacement of coal fly ash with mine tailings has the benefit of immobilizing trace elements, especially heavy metals. All regulated element concentrations from effluent during testing are well below the leachate quality criteria set by the local regulatory authority.},
doi = {10.1061/(ASCE)0899-1561(2006)18:2(140)},
journal = {Journal of Materials in Civil Engineering},
number = 2,
volume = 18,
place = {United States},
year = {Wed Mar 15 00:00:00 EST 2006},
month = {Wed Mar 15 00:00:00 EST 2006}
}
  • In the present research, industrial byproducts, namely, cement kiln dust (CKD) and Class C fly ash (FAC) have been used as candidate materials along with the partial addition of sulfate-resistant cement (SRC) in the Stabilization/solidification of polymetallic sulfidic mine tailings (MT). The effectiveness of S/S was assessed by comparing laboratory experimental values obtained from unconfined compressive strength, hydraulic conductivity and leaching propensity tests of S/S samples with regulatory standards for safe surface disposal of such wastes. Despite general regulatory compliance of compressive strength and hydraulic conductivity, some solidified/stabilized-cured matrices were found unable to provide the required immobilization of pollutants. Solidified/stabilizedmore » and 90-day cured mine tailings specimens made with composite binders containing (10% CKD + 10% FAC), (5% SRC + 15% FAC) and (5% SRC + 5% CKD + 10% FAC) significantly impaired the solubility of all contaminants investigated and proved successful in fixing metals within the matrix, in addition to achieving adequate unconfined compressive strength and hydraulic conductivity values, thus satisfying USEPA regulations. Laboratory investigations revealed that, for polymetallic mining waste, leachate concentrations are the most critical factor in assessing the effectiveness of S/S technology.« less
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  • A method for the direct determination of Sn in river sediments and coal fly ash is described. Samples were decomposed by a mixture of nitric, perchloric and hydrofluoric acid. A mixture of ascorbic acid and Fe was used to reduce matrix interferences. Sn was determined using graphite furnace AAS. Between 90 and to 100% Sn was recovered. The relative standard deviation was 2% for 7 replicate determinations of Sn in coal fly ash containing 2.5 ..mu..g Sn/g.
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