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Patterson, B.; Robertson, B.; Woodbury, R.; Talbot, B.; Davis, G.
doi: 10.1007/s10230-006-0125-3pmid: N/A
A high density polypropylene (HDPE) and bentonite composite cover, used to reduce oxygen ingress into a sulfidic tailings facility, was evaluated over a 7 year post-installation period between 1998 and 2005, and found to be a reliable long-term barrier to oxygen ingress and rainfall infiltration. The evaluation was based on multiple lines of evidence and included (i) changes in metal and inorganic concentrations in the regional ground water immediately underlying the tailings residue; (ii) oxygen concentrations from probes installed below the composite cover; (iii) changes in pore water levels within the tailings residue, and; (iv) changes in temperature of the vadose zone below the composite cover.
doi: 10.1007/s10230-006-0126-2pmid: N/A
The net acidity of a water sample can be measured directly by titration with a standardized base solution or calculated from the measured concentrations of the acidic and basic components. For coal mine drainage, the acidic components are primarily accounted for by free protons and dissolved Fe2+, Fe3+, Al3+, and Mn2+. The base component is primarily accounted for by bicarbonate. A standard way to calculate the acidity for coal mine drainage is: Acidcalc = 50*(2*Fe2+/56 + 3*Fe3+/56 + 3*Al/27 + 2*Mn/55 + 1000*10-pH)—alkalinity, where acidity and alkalinity are measured as mg/L CaCO3 and the metals are mg/L. Because such methods of estimating acidity are derived by independent laboratory procedures, their comparison can provide a valuable QA/QC for AMD datasets. The relationship between measured and calculated acidities was evaluated for 14 datasets of samples collected from mine drainage discharges, polluted receiving streams, or passive treatment systems, containing a total of 1,484 sample analyses. The datasets were variable in nature, ranging from watersheds where most of the discharges contained alkalinity to ones where all of the discharges were acidic. Good relationships were found to exist between measured and calculated acidities. The average acidity measurement was 239 mg/L CaCO3 and the average acidity calculation was 226 mg/L CaCO3. Linear regressions were calculated for individual datasets and for the entire dataset. The linear regression for the entire dataset was: Acidcalc = 0.98 * Acidmeas – 8, r2 = 0.98. The good correlation between calculated and measured acidity is the basis for an easy and inexpensive QA/QC for AMD data. Substantial variation between measured and calculated acidities can be used to infer sampling or analytical problems.
doi: 10.1007/s10230-006-0127-1pmid: N/A
The basic chemical properties of Tertiary (T) and Quaternary (Q) aquifers near the Piaseczno opencast sulphur mine and the water in the open pit, along with the stratigraphy and hydrogeology of the area, were characterized to assess the feasibility of inundating the mine with ground water. Ground water quality varied markedly in the opencast area. A distinct stratification was noted in the pit water; total dissolved solids, calcium, chloride, hardness, and hydrogen sulphide increased from the top water level to the bottom of the pit lake. The concentrations of SO4 2- and Cl- in the opencast water were very high, especially in the hypolimnion zone. Based on our preliminary analysis, it appears that an artificial lake formed in the Piaseczno open pit could be used in the future as a fish and wildlife habitat as well as for recreational purposes.
Zamzow, K.; Tsukamoto, T.; Miller, G.
doi: 10.1007/s10230-006-0128-0pmid: N/A
Alcohol-fed, semi-passive bioreactors have been used to support the growth of sulfate-reducing bacteria (SRB) for treatment of acid drainage from mine sites. An alcohol source not previously examined for use in these reactors is the glycerol-methanol waste remaining after the production of biodiesel fuel. In the laboratory, rock-filled columns were used to investigate biodiesel waste (BDW) as a carbon source for SRB. Columns were provided with water containing 900 mg/L sulfate, and fed reagent-grade glycerol or BDW in sufficient quantity to reduce 50% of the sulfate. Addition of 246 mg/L of reagent-grade glycerol resulted in 50% sulfate reduction and production of up to 59 mg/L of soluble sulfide, while the equivalent of 246 mg/L of glycerol provided as BDW resulted in 55% sulfate reduction and the production of up to 92 mg/L of soluble sulfide. During the initial stages of acclimation, propionic, acetic, formic, and lactic acids were observed. Acid concentrations were reduced over time in the effluent, and organic carbon in the BDW was nearly completely converted to carbon dioxide.
Alakangas, Lena; Öhlander, Björn
doi: 10.1007/s10230-006-0129-zpmid: N/A
Leachate water quality from covered and uncovered unoxidised sulphide-rich tailings in six pilot-scale (5x5x3 m3) test cells was monitored during 2004 and 2005. The covers consisted of a layer of clayey till, sewage sludge, apatite or Trisoplast (a commercial mixture of tailings, bentonite, and a polymer). All layers were protected by an unspecified till except in one reference cell, where the tailings were left open. All leachate waters showed near-neutral pH as a result of neutralization by calcite in the tailings and by Ca(OH)2 added prior to deposition. Average dissolved sulphur concentrations in the leachates were ≈ 600 mg L-1, except in the cell with sewage sludge (300 mg L-1). The source of sulphur was mainly pyrite oxidation, but residual sulphur probably remained from the enrichment process. The near-neutral pH favoured precipitation of metal-(oxy)hydroxides with subsequent removal of trace elements such as Cd, Cu and Pb (< 15 μg L-1) from the solutions. High concentrations of Co, Mn, Ni, and Zn were found in leachates from the apatite, Trisoplast, and uncovered tailings cells. High As concentrations were found in the leachates in the sewage sludge and clayey till cells. The lowest metal concentrations, redox potential, and highest pH were found in the sewage sludge cell. Decreased elemental metal concentrations during 2004 suggest improved performance over time.
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