Geotechnical Investigations on Tailings
Geomech Africa was recently contracted to conduct a geotechnical investigation of a Tailings Storage Facility (TSF) at a mine in South Africa. The project involved a combination of in-situ testing and core drilling to assess the subsurface conditions.
Scope of Work
Scope of Work
- CPTu testing and dissipation tests at 15 locations.
- Rotary core drilling (RC drilling) at 13 locations, with core extraction extending to bedrock.
- Installation of standpipe piezometers at each drilling location, complete with concrete blocks and lockable stands.
Technical Challenges Overcome
Due to the sensitive nature of the investigation at the tailings storage facility (TSF) site, the team had to modify the water pumping rate during the conventional rotary core drilling to minimize the amount of water injected into the TSF. This adjustment, necessary for cooling the coring bit and lubricating the hole, led to challenges such as stuck rods and casing. Through a collaborative effort between the client and Geomech Africa, the team effectively addressed these issues, ensuring both high-quality core recovery and the maintenance of safe operational procedures.
During the CPTu testing, the team faced another challenge: extremely high cone tip resistance values that exceeded the Pagani CPTu probe’s 50 MPa limit, reaching up to 88 MPa. Consequently, the team had to terminate these tests and extract the rods. To overcome this, a rotary core drill rig was mobilized to drill through the hard layers at the exact test locations. Following this, the CPTu rig was repositioned to resume testing and achieve the target depth.
The primary goal of the CPTu testing at this TSF site was to determine the phreatic water level through dissipation testing. The team completed a total of 1242 minutes of dissipation tests and conducted 456 meters of CPTu probing. This testing provided valuable subsurface information, including soil classification, strength measurements, deformation characteristics, and permeability of foundation soils, which was crucial for timely feedback to the client
Safety First
Geomech Africa prioritises safety on all projects. Daily toolbox talks and a strong focus on safety procedures ensured a successful completion with zero incidents or accidents. On this project, there were zero accidents and zero harm. Positive results when you have an experienced SHE rep on-site and a supervisor ensuring all safety procedures and safe work procedures are followed.
Project Outcome
The project successfully achieved all objectives, including:
Due to the sensitive nature of the investigation at the tailings storage facility (TSF) site, the team had to modify the water pumping rate during the conventional rotary core drilling to minimize the amount of water injected into the TSF. This adjustment, necessary for cooling the coring bit and lubricating the hole, led to challenges such as stuck rods and casing. Through a collaborative effort between the client and Geomech Africa, the team effectively addressed these issues, ensuring both high-quality core recovery and the maintenance of safe operational procedures.
During the CPTu testing, the team faced another challenge: extremely high cone tip resistance values that exceeded the Pagani CPTu probe’s 50 MPa limit, reaching up to 88 MPa. Consequently, the team had to terminate these tests and extract the rods. To overcome this, a rotary core drill rig was mobilized to drill through the hard layers at the exact test locations. Following this, the CPTu rig was repositioned to resume testing and achieve the target depth.
The primary goal of the CPTu testing at this TSF site was to determine the phreatic water level through dissipation testing. The team completed a total of 1242 minutes of dissipation tests and conducted 456 meters of CPTu probing. This testing provided valuable subsurface information, including soil classification, strength measurements, deformation characteristics, and permeability of foundation soils, which was crucial for timely feedback to the client
Safety First
Geomech Africa prioritises safety on all projects. Daily toolbox talks and a strong focus on safety procedures ensured a successful completion with zero incidents or accidents. On this project, there were zero accidents and zero harm. Positive results when you have an experienced SHE rep on-site and a supervisor ensuring all safety procedures and safe work procedures are followed.
Project Outcome
The project successfully achieved all objectives, including:
- Completion of 15 CPTu tests and dissipations
- Rotary core drilling, core extraction, and piezometer installation at 13 locations, with accurately drilling through hard layers ensuring no missing data when the CPTu testing will continue.
This project demonstrates Geomech Africa's expertise in challenging environments, their ability to overcome any obstacles, and their unwavering commitment to safety.
Plot 28 Central Road
Sunrella, Lanseria
Gauteng
South Africa
Tel. +27 (0)11 966 7760
Email. info@geogroup.co.za