Minister Pemmy Majodina launches tunnel boring machine for Polihali water project in Lesotho
Ministers Majodina and Moleko unveil tunnel boring machine to kickstart excavation of 38.5 km Polihali Water Transfer Tunnel
The Minister of Water and Sanitation, Pemmy Majodina, along with Deputy Minister David Mahlobo and Lesotho’s Minister of Natural Resources, Mohlomi Moleko, has unveiled the Tunnel Boring Machine (TBM) at the Polihali construction site in Mokhotlong, Lesotho.
The TBM will be used to drill the 38.5 km tunnel connecting the Polihali and Katse dams. The unveiling took place on Monday, April 20, 2026, marking a key step forward in the project’s implementation.
Following the successful launch of the first TBM at Katse Dam in February last year, the introduction of this second machine represents a significant milestone in Phase 2 of the Lesotho Highlands Water Project. It signals the transition from preparation to full-scale tunnelling along one of the region’s most ambitious water transfer routes.
The Polihali tunnel is a critical component of the project, stretching 38.5 kilometres to link the Polihali and Katse dams into a single gravity-driven system. This design allows water to be transported efficiently without the need for pumping. As such, the TBM plays a vital role in physically connecting the two nations through a shared water infrastructure system.
“Measuring roughly 423 meters in length and featuring a 5.38-meter cutterhead and engineered to work continuously even in the toughest underground conditions, the two TBMs will excavate the belly of the Maluti mountains that will connect Polihali and Katse reservoirs, advancing simultaneously from each end of the alignment to create a tunnel. During this process, the machine will also install precast concrete lining segments, seamlessly transforming raw rock into a completed structure in one uninterrupted process,” reads a statement from the Department of Water and Sanitation.
Construction of the Polihali tunnel is currently underway. Once completed, it will enable the transfer of significantly larger volumes of water, thereby strengthening regional water security and supporting hydropower generation in Lesotho.
