In-situ testing in Piet Retief

Geomech Africa completed a project in the KwaZulu-Natal town of Piet Retief, which involved the drilling of six boreholes around a dam to conduct Lugeon testing and install standpipe piezometers. The primary goal of the project was to assess the rate of water seepage through the soil surrounding the dam. Each borehole, ranging from 22 to 38 meters in depth, required an average of four Lugeon tests. 

Lugeon testing is a standard hydrogeological method used to determine the permeability of rock mass. By measuring the rate of water injection into the borehole under pressure, engineers can assess the potential for water leakage and make informed decisions of dam safety measures based on the data collected.

One of the primary challenges faced by the Geomech Africa team was the presence of a soft, saturated soil layer beneath the top layer. This layer proved difficult to drill using traditional rotary core drilling methods, as the soil was too soft to support core recovery. To overcome this obstacle, branch Manager Dries de Beer devised a creative solution. By pausing the drilling process when reaching the soft layer and using the rig to push the core barrel into the ground, the team was able to achieve 100% core recovery.

The project was further complicated by a week of extreme cold weather, with temperatures plummeting to -3 degrees Celsius. Despite the harsh conditions, the team persevered, utilising appropriate cold-weather protective equipment to ensure safety and productivity.

To ensure the long-term integrity of the project, each standpipe location was marked with a prominent yellow concrete pole. These markers serve as visual indicators for both vehicular traffic and data retrieval teams, preventing accidental damage and facilitating future monitoring efforts.

The successful completion of this project was a result of effective teamwork and innovative problem-solving. By working in tandem, the drilling and testing teams were able to optimise efficiency and minimise project timelines. The 100% core recovery achieved is a testament to the team's technical expertise and dedication to delivering high-quality results under difficult drilling conditions.