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Author Eger, P.; Melchert, G.; Wagner, J.
Title Using passive treatment systems for mine closure – A good approach or a risky alternative? Type Journal Article
Year 2000 Publication Min. Eng. Abbreviated Journal
Volume 52 Issue (up) 9 Pages 78-83
Keywords Pollution and waste management non radioactive Groundwater problems and environmental effects geological abstracts: environmental geology (72 14 2) geomechanics abstracts: excavations (77 10 10) acid mine drainage decommissioning mine waste open pit mine pH remediation
Abstract In 1991, LTV Steel Mining decided to close an open-pit taconite mine in northeastern Minnesota using a passive-treatment approach consisting of limiting infiltration into the stockpiles and wetland treatment to remove metals. More than 50 Mt (55 million st) of sulfide-containing waste had been stockpiled adjacent to the mine during its 30 years of operation. Drainage from the stockpiles contained elevated levels of copper, nickel, cobalt and zinc. Nickel is the major trace metal in the drainages. Before the closure, the annual median concentrations ranged from 1.5 to 50 mg/L. Copper, cobalt and zinc are also present but they are generally less than 5% of the nickel values. Median pH levels range from 5 to 7.5, but most of the stockpile drainages have pH levels greater than 6.5. Based on the chemical composition of each stockpile, a cover material was selected. The higher the potential that a stockpile had to produce acid drainage, the lower the permeability of the capping material required. Covers ranged from overburden soil removed at the mine to a flexible plastic liner. Predictions of the reduction in infiltration ranged from 40% for the native soil to more than 90% for the plastic liner. Five constructed wetlands have been installed since 1992. They have removed 60% to 90% of the nickel in the drainages. Total capital costs for all the infiltration reduction and wetlands exceeded $6.5 million, but maintenance costs are less than 1% of those for an active treatment plant. Because mine-drainage problems can continue for more than 100 years, the lower annual operating costs should pay for the construction of the wetland-treatment systems within seven years.
Address P. Eger, Minnesota Dept. of Natural Rsrces., St. Paul, MN, United States
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ISSN 0026-5187 ISBN Medium
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Notes Using passive treatment systems for mine closure – A good approach or a risky alternative?; 2285715; United-States 19; Geobase Approved no
Call Number CBU @ c.wolke @ 17539 Serial 392
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Author Wolkersdorfer, C.
Title Mine water tracer tests as a basis for remediation strategies Type Journal Article
Year 2005 Publication Chemie der Erde Abbreviated Journal
Volume 65 Issue (up) Suppl. 1 Pages 65-74
Keywords Mine water treatment Stratification Convection First flush Tracer tests Microspheres Reactive transport Groundwater problems and environmental effects Pollution and waste management non radioactive acid mine drainage remediation
Abstract Mining usually causes severe anthropogenic changes by which the ground- or surface water might be significantly polluted. One of the main problems in the mining industry are acid mine drainage, the drainage of heavy metals, and the prediction of mine water rebound after mine closure. Therefore, the knowledge about the hydraulic behaviour of the mine water within the flooded mine might significantly reduce the costs of mine closure and remediation. In the literature, the difficulties in evaluating the hydrodynamics of flooded mines are well described, but only few tracer tests in flooded mines have been published so far. Most tracer tests linked to mine water problems were related to either pollution of the aquifer or radioactive waste disposal and not the mine water itself. Applying the results of the test provides possibilities f or optimizing the outcome of the source-path-target methodology and therefore diminishes the costs of remediation strategies. Consequently, prior to planning of remediation strategies or numerical simulations, relatively cheap and reliable results for decision making can be obtained via a well conducted tracer test. < copyright > 2005 Elsevier GmbH. All rights reserved.
Address C. Wolkersdorfer, TU Bergakademie Freiberg, Lehrstuhl fur Hydrogeologie, 09596 Freiberg, Sachsen, Germany c.wolke@tu-freiberg.de
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Series Volume Series Issue Edition
ISSN 0009-2819 ISBN Medium
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Notes Sep 19; Mine water tracer tests as a basis for remediation strategies; 2767887; Germany 34; Geobase Approved no
Call Number CBU @ c.wolke @ 17499 Serial 34
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