The Lesotho Highlands Development Authority (LHDA) is eagerly awaiting of first of two massive Tunnel Boring Machines (TBMs) set to arrive in Durban on August 26, marking a significant step forward in Phase II of the Lesotho Highlands Water Project (LHWPII). This phase, which includes the construction of the 38-kilometer PolihaliTransfer Tunnel, is essential for advancing water supply and energy production in the region.
The TBM, which has been manufactured by CCCC Tianhein China and designed by the US -based company Robbins, will be transported to Lesotho in parts. These components, including shields and a cutter head, weigh over 900 tons and will be assembled into a machine that is 350 meters long. Once fully assembled, this enormous machine will begin its journey to excavate the PolihaliTransfer Tunnel from the Leribe side. This tunnel will connect the Polihali reservoir to the Katse reservoir, enabling the gravity-driven transfer of water between these key resources.
In keeping with tradition, the LHDA has launched a competition to name the TBM, inviting Basotho people from across the country and the diaspora to participate. The name should reflect the strength, power, and tenacity associated with the Lesotho Highlands and Leribe district, where the TBM will begin its work. Participants are encouraged to draw inspiration from local legends, leaders who have shown resilience and dedication, and figures who have contributed significantly to science, infrastructure, or peace in the region. The competition will be hosted on multiple platforms, including social media and local radio stations, starting on August 28, 2024.
A panel will select the top 10 names, and the public will have the opportunity to vote for the winning name. The person who submits the chosen name will receive recognition and prizes at the official naming ceremony, marking their place in the history of the Lesotho Highlands Water Project.
This TBM, tailored to the challenging basalt rock formations in the Mokhotlong and Leribe districts, is a marvel of modern engineering. Its design has been carefully verified by a team of LHDA senior engineers, consultants, and contractors during a recent inspection at a CCCC Tianhe plant in Changshu City, Jiangsu Province, China. This inspection, known as the Factory Acceptance Test, took place from May 8 to 11, 2024. The LHDA team, along with representatives from Metsi a Senqu KhubeluConsultants (MSKC) and the Kopano Ke Matla Joint Venture, which is constructing the tunnel, ensured that the TBM meets the specific requirements for the PolihaliTransfer Tunnel.
“The TBMs have been specifically designed to handle the challenging basalt rock formations in the Mokhotlong and Leribe districts where the transfer tunnel is being constructed,” said Neo Thinyane, Phase II Senior Projects Engineer.
The inspection included a thorough examination of the cutter heads, backup systems, and segment erection mechanisms. The team also assessed the functionality of critical systems such as muck removal, conveyor belts, power supply, ventilation, water supply, and dewatering systems.
Once the TBM arrives in Lesotho, its parts will be transported to the Katse TBM access edit at Ha Bereng, Leribe, where preparations are already underway. The assembly of the TBM is expected to take about 50 days before it starts its monumental task of tunnelling through the mountains.
The Polihali Transfer Tunnel is a crucial component of Phase II of the Lesotho Highlands Water Project. The tunnel works include intake works and a gate shaft at the Polihali reservoir, outlet works and a gate shaft at the existing Katse reservoir with an underwater connection to the lake, and access edits to the waterway. This infrastructure will significantly boost the region’s capacity to manage its water resources, supporting both local communities and broader economic development.
As the TBM makes its way to Lesotho, excitement is building among engineers, project managers, and the local population alike. This giant machine represents more than just a piece of technology; it is a symbol of progress, collaboration, and the determination of the Basotho people to build a brighter future for their country. The naming competition adds a cultural and community-driven element to the project, ensuring that this milestone will be remembered for generations to come.
The Polihali to Katse Transfer Tunnel will be excavated using a combination of tunnel boring and drill-and-blast methods, with work proceeding from both the Leribe and Polihali ends. The arrival of the second TBM, scheduled for early next year, will further accelerate the progress of this monumental project.
The LHDA remains committed to engaging with the local community and honouring the rich cultural heritage of Lesotho. The arrival of the TBM not only marks a technical achievement but also a celebration of the unity and strength of the Basotho people as they work together to achieve a common goal.
