Two workers died and eight suffered injuries when concrete lining fell off an adit wall during tunnel clearing works in late January at Dulhasti hydropower project in India.
T&TI was told by the client, National Hydroelectric Power Corp (NHPC), that the workers were removing dewatering pipes from the wall of the adit when the fatal accident happened.
Investigations are underway into what caused a stretch of nearly 6m of mass concrete lining, 300mm-400mm thick, to fall from the tunnel wall during the labour-intensive work.
The men were working near the headrace tunnel plug when the accident happened. Some five-to-six pipes of 180mm diameter were being removed.
Excavation works on the much-delayed hydro scheme in the Himalayan state of Jammu & Kashmir were finished, but the upstream adit had been used for a TBM drive.
Tunnelling works on the project involved driving 7.46m and 7.7m diameter stretches along the 10.6km headrace, and excavation of a 7.46m diameter tailrace barely 300m long.
Work on the 390MW project originally started in the early 1980s but the scheme was beset with financial, construction, contractual and political problems. Commissioning works are underway.
