2019 SME Annual Conference & Expo

Chris Pantano (Presenter), Gustavo Meza-Cuadra, Doug Oliver (Co-authors)
Geotechnical and groundwater modeling: An integrated approach for block cave mining (Session: Mining & Exploration: Geosciences: Underground Mine Geotechnical I)
Tuesday, February 26, 10:00 AM

Colorado Convention Center, Room 503Block cave mining significantly alters in-situ rock hydraulic properties, resulting in increases to hydraulic conductivity and specific yield values by orders of magnitude. Although simplistic assumptions regarding hydraulic property changes can be approximated, geotechnical modeling offers valuable data that allows for more detailed estimates of rock-mass changes, particularly with respect to timing and scale. Collaboration with geotechnical engineers and translation of this data into hydraulic property changes is valuable to improve groundwater model predictions. A case study presents the utilization of geotechnical model output and translation methods for integrated groundwater modeling, providing higher confidence predictions.

Ned Clayton (Presenter)
In-Situ Characterization and Pilot Injection Well Leach Testing to Evaluate and Optimize Secondary Recovery of Gold
From Old Heaps (Session: MPD: Chemical Processing: Secondary Value Recovery)
Wednesday, February 27, 2:00 AM
Colorado Convention Center, Room 703

Previously-leached gold ore heaps at two neighboring mines are being assessed for leach reactivation using raffinate injection wells to recover residual gold using innovative in-situ characterization, modeling, pilot testing and real-time monitoring techniques. Phase 1 involved comprehensive characterization of the heaps using sonic core drilling; core chemistry, metallurgy, mineralogy, and leachability lab analysis; advanced geophysical logging for in-situ hydrogeology and mineralogy evaluation; and 3D property and unsaturated flow injection numerical modeling to determine feasibility and best options for secondary gold recovery. Phase 2 consists of targeted injection pilot well leach testing, including intensive 3D monitoring of leach solution movement and chemistry in the subsurface.