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Weeks, R. E., Krohn, R., & Walker, T. H. (2000). Water management during the Pinto Valley removal action. In Tailings and Mine and Waste 2000, Proceedings of the Seventh International Conference, Fort Collins, US, Jan 22 26, 2000 (pp. 499–506).
Abstract: Der Bruch des Dammes einer Halde der Grube Nr. 14 des Kupfer- Bergbaubetriebes Pinto Valley in Arizona, USA, im Jahre 1997 führte zum Eintrag von 370000 yd(exp 3) Bergematerials und Tailings in das Bett des Flusses Pinto Creek, USA, wodurch letzteres blockiert wurde. Der Vorfall ereignete sich in bergigem Gelände unterhalb eines 14 Quadratmeilen großen Abschnittes des Flusseinzugsgebietes oberhalb des Sees Roosevelt Lake, USA, einer Trinkwasserquelle für Phoenix, USA. Aufgrund der Bedeutung des Gebietes wurde eine Strategie zur Verhütung weiterer Beeinträchtigungen der Wasserqualität ausgearbeitet. Diese beinhaltete Managementaspekte zur Gewährleistung einer schnellen Planung und Ausführung der notwendigen Arbeiten gekoppelt mit der Planung, dem Bau und dem Betrieb von Rückhalte und Umleitungssystemen für auftretende Wässer. Die Auslegung dieser Systeme erfolgte auf der Grundlage der Daten des Einzugsgebietes und der klimatischen Verhältnisse, wobei verschiedene Wahrscheinlichkeiten der Überschreitung der ermittelten Werte berücksichtigt wurden. Innerhalb von acht Monaten konnten die Tailings aus dem betroffenen Gebiet entfernt werden, ohne dass belastete Oberflächenwässer freigesetzt wurden.
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Watzlaf, G. R., Schroeder, K. T., & Kairies, C. L. (2000). Proceedings, 17th Annual National Meeting – American Society for Surface Mining and Reclamation. Tampa.
Abstract: Ten passive treatment systems, located in Pennsylvania and Maryland, have been intensively monitored for up to ten years. Influent and effluent water quality data from ten anoxic limestone drains (ALDs) and six reducing and alkalinity-producing systems (RAPS) have been analyzed to determine long-term performance for each of these specific unit operations. ALDs and RAPS are used principally to generate alkalinity, ALDs are buried beds of limestone that add alkalinity through dissolution of calcite. RAPS add alkalinity through both limestone dissolution and bacterial sulfate reduction. ALDs that received mine water containing less than 1 mg/L of both ferric iron and aluminum have continued to produce consistent concentrations of alkalinity since their construction. However, an ALD that received 20 mg/L of aluminum experienced a rapid reduction in permeability and failed within five months. Maximum levels of alkalinity (between 150 and 300 m&) appear to be reached after I5 hours of retention. All but one RAPS in this study have been constructed and put into operation only within the past 2.5 to 5 years. One system has been in operation and monitored for more than nine years. AIkalinity due to sulfate reduction was highest during the first two summers of operation. Alkalinity due to a limestone dissolution has been consistent throughout the life of the system. For the six RAPS in this study, sulfate reduction contributed an average of 28% of the total alkalinity. Rate of total alkalinity generation range from 15.6 gd''rn-'to 62.4 gd-'mL2 and were dependent on influent water quality and contact time.
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Turek, M. (2000). Recovery of NaCl from saline mine water in the ED-MSF system. 8th World Salt Symposium, Vols 1 and 2, , 471–475.
Abstract: A considerable part of water obtained by drainage of Polish coal-mines is saline which creates substantial ecological problems. The load of salt (mainly sodium chloride) amounts to 5 min t/year. Despite the utilisation of saline coalmine waters is considered to be the most adequate method of solving ecological problems caused by this kind of water in Poland there are only two installations utilising coal-mine waters and producing 100,000 t salt per year. In the case of the most concentrated waters, the so-called coal-mine brines, the method of concentrating by evaporation in twelve-stage expansion installation or vapour compression is applied, after which sodium chloride is manufactured. In the case of low salinity waters they are preconcentrated first by RO method. High energy consumption in above-mentioned methods of evaporation is a considerable restriction in the utilisation of coal-mine brines. An obstacle in the application of low energy evaporation processes, e.g. multi-stage flash, is the high concentration of calcium and sulphate ions in the coal-mine waters.
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Tempel, R. N. (2000). A quantitative approach to optimize chemical treatment of acid drainage using geochemical reaction path modeling methods: Climax Mine, Colorado. ICARD 2000, Vols I and II, Proceedings, , 1053–1058.
Abstract: The Climax Mine, near Leadville, Colorado treats acid drainage in a lime neutralization chemical treatment system. Chemical treatment has been successful in reducing the concentration of metals to below surface water discharge effluent limits, but lime usage has not been optimized. A geochemical modeling approach has been developed to increase the efficiency of lime neutralization. The modeling approach incorporates two steps: (1)calibration, and (2) calculation of amount of lime needed to increase pH and remove metals. Results of our work quantify the lime treatment process and improve our ability to predict overall water quality.
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Swayze, G. A. (2000). Imaging spectroscopy: A new screening tool for mapping acidic mine waste. ICARD 2000, Vols I and II, Proceedings, , 1531–+.
Abstract: Imaging spectroscopy is a relatively new remote sensing tool that provides a rapid method to screen entire mining districts for potential sources of surface acid drainage. An imaging spectrometer known as the Airborne Visible/InfraRed Imaging Spectrometer (AVIRIS) measures light reflected from the surface in 224 spectral channels from 0.4 – 2.5 mum. Spectral data from this instrument were used to evaluate mine waste at the California Gulch Superfund Site near Leadville, Colorado. Here, the process of pyrite oxidation at the surface produces acidic water that is gradually neutralized as it drains away from mine waste, depositing a central jarosite zone surrounded by a jarosite + goethite zone, in turn surrounded by a goethite zone with a discontinuous hematite rim zone. Leaching tests show that pH is most acidic in the jarosite and jarosite+goethite zones and is near-neutral in the goethite zone. Measurements indicate that metals leach from minerals and amorphous materials in the jarosite + goethite and jarosite zones at concentrations 10 – 50 times higher than from goethite zone minerals. Goethite zones that fully encircle mine waste may indicate some attenuation of leachate metals and thus reduced metal loading to streams. The potential for impact by acidic drainage is highest where streams intersect the jarosite and jarosite + goethite zones. In these areas, metal-rich acidic surface runoff may flow directly into streams. The U.S. Environmental Protection Agency estimates (U.S. EPA, 1998) that mineral maps made from AVIRIS data at Leadville have accelerated remediation efforts by two years and saved over $2 million in cleanup costs.
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