Mussoorie, July 17 -- A 22-year-old construction worker from Jharkhand was killed after a section of the Silkyara concrete lining inside the -Barkot tunnel collapsed in Uttarkashi district during the early hours of Thursday, officials said. District magistrate Prashant Arya said the accident occurred at around 2 am, nearly 900 metres from the Barkot end of the 4.5-km-long tunnel, while construction and maintenance work was underway. "The incident occurred when a heavy section of the tunnel's concrete shotcrete lining fractured and collapsed on the worker," Arya said. The worker sustained fatal injuries after being struck by the falling debris and died at the site, he added. No other workers were trapped in the collapse and the tunnel remained accessible, Arya said, adding that the final details will be available only after the complete inquiry report is submitted. The district magistrate directed senior district officials, including the sub-divisional magistrate (SDM), Barkot, to visit the site, assess the situation and submit a detailed report....