Guiding Final Closure Options through Quantification of Internal Mine Rock Stockpile Conditions

Mining companies often hold legacy mine rock stockpiles (MRSs) that pose some level of environmental risk through contaminant release or erosion. Okane conducted a drilling program across five MRSs to investigate the physical and chemical characteristics of mine rock within each MRS, as there were no dumping records. Instrumentation was installed within the boreholes during drilling to monitor internal conditions. The program’s objectives were to understand and quantify the nature and scale environmental issues so that effective closure options could be developed for the legacy site

Okane developed a sonic drilling program, involving 19 boreholes, which were logged onsite and sent to the laboratory for physical and geochemical analysis. Geochemical testing included a kinetic testing program for materials collected during drilling to provide key parameters associated with reactive wastes. Over 90 downhole sensors were fitted into the boreholes during drilling, reaching depths of up to 40 meters. These sensors included galvanic oxygen probes, soil matric potential sensors, temperature sensors, and vibrating wire piezometers. Monitoring internal MRS conditions in response to environmental factors, combined with internal MRS characteristics, allowed Okane to inform potential closure options for the site.

The investigation has provided the client with a comprehensive understanding of the site’s geochemistry, hydrology, and geophysical properties to produce effective closure options.