Regions: South Slave Region
Tags: contaminants, water quality, geochemistry, diamond mining, waste rock, acidity
| Principal Investigator: | Blowes, David W. (24) |
| Licence Number: | 17247 |
| Organization: | University of Waterloo |
| Licensed Year(s): |
2023
|
| Issued: | Apr 28, 2023 |
| Project Team: | David Wilson, Jeff Bain |
Objective(s): To characterize the geochemical evolution of the waste-rock contained in Pigeon waste-rock storage area to refine management solutions for this waste stream.
Project Description: This licence has been issued for the scientific research application No.5492. The objective of this project is to characterize the geochemical evolution of the waste-rock contained in Pigeon waste-rock storage area to refine management solutions for this waste stream. The proposed research activities will involve field collection of Pigeon waste-rock samples and installation of monitoring equipment at the Ekati site. Waste-rock samples will be collected from depth discrete and laterally- discrete zones within the waste-rock pile. Instrumentation for determination of physical and chemical conditions within the waste-rock pile will be installed on horizontal benches and extended laterally beyond the anticipated footprint of the pile. The instrumentation will measure temperature (thermistor strings), water quality (soil-water suction samplers; SWSS), moisture content (EcH2O probes), and pore-gas O2 and CO2 concentrations (gas-sampling bundles). Many of the instruments will be connected to data loggers to provide frequent measurements throughout the year. The results of the humidity-cell tests will provide insights into sulfide-mineral weathering, acid generation, and metal(loid)-leaching properties of the waste rock. Pore water will be extracted from the waste-rock matrix and characterized, including measurement of pH, Eh, alkalinity, conductivity, dissolved cations (via inductively coupled plasma – mass spectrometry, ICP-MS, and inductively coupled plasma – optical emission spectroscopy, ICP-OES), and dissolved anions (via ion chromatography, IC). Mineralogical composition of the waste-rock samples will be determined through optical microscopy and powder X-ray diffraction (XRD). Solid-phase elemental composition and morphological characteristics will be evaluated using scanning electron microscopy – energy dispersive X-ray spectroscopy and X-ray fluorescence (XRF). Carbon/sulfur analysis and acid-base accounting will be used to assess the acid-generating characteristics of the waste rock. Results from the waste-rock sample characterization will be integrated into the reactive transport model, MIN3P (Mayer et al., 2002), and will be used to simulate drainage-water quality at the field scale, including potential acid generation and metal(loid) leaching. The research team will provide Arctic Canadian Diamond Company with progress reports, which will include detailed research progress updates and data summaries. In addition, the results of this research will be described in academic theses, conference presentations, conference proceedings papers, and refereed journal articles. The research team will interact directly with personnel involved in site operation at Ekati Diamond Mine. The fieldwork for this study will be conducted from April 30, 2023 to December 31, 2023.
