Lesotho Awards Two Geotechnical Investigation Contracts for the 120MW Oxbow Hydropower Project

en.Wedoany.com Reported - On October 6, the Lesotho Highlands Development Authority recently awarded two geological investigation contracts for the Oxbow Hydropower Project, with a total value of approximately M106 million. The first-phase contract was awarded to Open Ground Resources at M6 million, covering geophysical surveys, on-site geological mapping and related measurements, with a planned completion period of about 5 months; the second-phase contract was awarded to South Africa's GEOMECH AFRICA at approximately M100 million, covering borehole drilling, in-situ testing and laboratory testing, with an overall investigation period of about 11 months.

The second-phase geological investigation plans to drill 18 vertical, inclined and near-horizontal boreholes, with a cumulative drilling length of approximately 2,648 meters. On-site tests include hydraulic conductivity, groundwater pressure levels, Lugeon tests, hydraulic fracturing stress tests and standard penetration tests; laboratory work includes acid-soluble chloride and sulfate testing of aggregates, alkali-aggregate reaction potential, water absorption, methylene blue testing, X-ray diffraction and petrographic analysis. Subcontractors for this phase include South Africa's Skyhorse Aviation, Open Ground Resources and Germany's Sol Experts.

The Oxbow Hydropower Project is located in the Malibamatso River basin in northern Lesotho and forms part of the hydropower component of Phase II of the Lesotho Highlands Water Project. According to the Lesotho Highlands Development Authority's previous project procurement documents, the scope of works includes an approximately 100-meter-high dam, intake structures, an approximately 6.6-kilometer headrace tunnel, an approximately 3.2-kilometer steel penstock, a powerhouse, a tailrace channel, and an approximately 4.2-kilometer water transfer tunnel; the powerhouse scheme is configured with 4 Pelton turbines and 4 generators of 23.3 MVA each.

The project's engineering design and construction supervision work has already been initiated. In 2024, the Lesotho Highlands Development Authority awarded the design and construction supervision services contract for the Oxbow Hydropower Project. The ASG joint venture undertaking the relevant work consists of France's Artelia, SMEC International, SMEC South Africa and Lesotho's GWC Consulting Engineers. The contract has a duration of 92 months and a value of approximately M824 million, with engineering design work commencing in early 2025.

The project's environmental and social impact assessment work was launched on January 6, 2025, implemented by a joint venture comprising ELC, Greenway Consultancy and Green Gold Group, with the related work planned to continue until 2027. The Lesotho Highlands Development Authority's procurement records also show that the Oxbow project has separately advanced preliminary work including environmental and social assessment, resettlement planning and engineering design.