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PREVENTION OF ACID MINE DRAINAGE GENERATION FROM OPEN-PIT MINE HIGHWALLS
Citation:
Bless*, D R., L. McCloskey, J. LeFever, AND D. Jordan. PREVENTION OF ACID MINE DRAINAGE GENERATION FROM OPEN-PIT MINE HIGHWALLS. Presented at Natl Assoc. of Abandoned Mine Land Programs 25th Annual Conference, Louisville, KY, September 28 - October 01, 2003.
Impact/Purpose:
To inform the public
Description:
Exposed, open pit mine highwalls contribute significantly to the production of acid mine
drainage (AMD) thus causing environmental concerns upon closure of an operating mine. Available information on the generation of AMD from open-pit mine highwalls is very limited. Most likely, this is due to the difficulty and danger of physically working on or near the face of the highwall. Four innovative technologies were evaluated under the U.S. Environmental Protection Agency's Mine Waste Technology Program (MWTP), Prevention ofacid Mine Drainage Generationfrom Open-Pil Mine Highwalls Project. The objective of the field demonstration was to evaluate the technologies ability to decrease or eliminate acid generation from treated plots in comparison to an untreated plot on the highwall.
The field demonstration was performed at the Golden Sunlight Mine (GSM), a subsidiary of Place Dome U.S., located near Whitehall, Montana, GSM is currently an operating mine.
For this demonstration, four technologies having potential to passivate the AMD from a highwall were selected. The highwall was divided into five plots measuring 50 feet by 50 feet. Each technology was assigned a plot with the fifth plot designated as the background plot. The four technologies were spray-applied by the technology vendors. The applied in-situ treatment technologies were: 1) a modified, furfuryl alcohol resin sealant, utilizing wood and agricultural byproducts to coat the rock surface; 2) EcobondTm ARD, a phosphate based process that forms a stable, insoluble compound, coating the rock surface; 3) two ARD passivation technologies, magnesium oxide and the Dupont technology developed to create an inert layer/coating on the pyrite, preventing oxidation.
The technologies were evaluated by: analysis of residual highwall rinse samples from treated plots, Accelerated Weathering of Solid Materials using Modified Humidity Cells; microscopy and other methods.
This project was funded under the EPA's Mine Waste Technology Program (MWTP). The MWTP is conducted under an interagency agreement, IAG ID No. DWS9938513-01-0, between the U.S. EPA and the U.S. DOE, Contract Number DE-AC22-96EW96405