Assessment of feasibility dewatering for Star and Orion South pits and hydrogeological impacts

Author(s): 
Vladimir Ugorets, Cristian Pereira
Date: 
Thursday, May 19, 2016
First presented: 
Water in Mining 2016
Type: 
Published paper
Category: 
Hydrogeology
Water Management
 
 
The Star-Orion South Diamond Project is located in Saskatchewan, Canada within the Fort a La Corne kimberlite area in complex hydrogeological settings. Two kimberlite pipes penetrate a very transmissive deep regional groundwater system which will be excavated by two proposed pits. Large scale active pit dewatering is required for the project. The purpose of the study was to assess Feasibility Level dewatering requirements and to evaluate possible hydrogeological impacts to the shallow groundwater system and surface-water bodies in the vicinity of the project.
 
This paper presents the results of a multiyear hydrogeological study to define the large scale dewatering requirements for the Star-Orion South Diamond Project in Saskatchewan, Canada, and to characterize possible hydrogeological impacts to the shallow groundwater system and surface-water bodies in the vicinity of the project. Two kimberlite pipes penetrate a very transmissive deep regional groundwater system and the proposed pit excavations require implementation of an active dewatering system with a pumping rate up to 120,000 m3/d. To assess the hydrogeological needs of the project in support of the Feasibility Dewatering and Environmental Impact Studies the authors developed a numerical groundwater flow model, which was calibrated to water level and pumping test data from numerous hydrogeological wells, including a 20 day pumping test from a prototype dewatering well with a pumping rate of about a 5,450 m3/d. Model predictions include: passive inflow to the proposed pits, the number and locations of required dewatering wells, their respective pumping rates and residual passive inflow to the pits, installation schedule of the dewatering wells, power costs for the proposed dewatering system, propagation of drawdown during proposed dewatering, backfilling of one pit and pit lake infilling of another pit, and the impact of groundwater discharge to the Saskatchewan River and creeks (during both pit excavations and infilling of the pit lake).
 

Feature Author

Dr. Vladimir Ugorets

Dr. Vladimir Ugorets, Principal Hydrogeologist, has more than 35 years of professional experience in hydrogeology, developing and implementing groundwater flow and solute-transport models related to mine dewatering, groundwater contamination, and water resource development.  Dr. Ugorets’ areas of expertise are in design and optimization of extraction-injection wellfields, development of conceptual and numerical groundwater flow and solute-transport models, and dewatering optimization for open-pit, underground and ISR mines.

Principal Consultant - Groundwater Management and Hydrogeology
PhD
SRK Denver
Cristian Pereira
Cristian Pereira is a geologist with more than 15 years of experience executing projects in the area of hydrogeology in Chile, USA, Canada, Colombia, Phillippines, Mexico and Argentina, with emphasis in conceptual and numeric modeling, as well as evaluation of underground water resources, mine dewatering requirements, environmental impacts of mining, pit lake infilling, brine extraction and pore pressure analysis. He has experience in field work, including control of Barber and Reverse Air type drilling, regional and local geological mapping, design and supervision of long and short duration pumping tests, and work with instruments with pressure transducers. He is skilled in the preparation of interpretative and compilation reports, management and creation of data bases (hydrological, bibliographic) and logistics. He has experience with hydrogeological interpretative software (Hidrochem, Aquifer Test, Aquasolve, among others), of Hydrogeological Modeling (Visual ModFlow and FeFlow) and geographic information systems (MapInfo).
Senior Hyrdogeologist
SRK Denver
SRK Worldwide