Uttarkashi, Nov 27 : Sixteen days have passed since the Silkyara tunnel accident took place in Uttarakhand's Uttarkashi, but no visible success has been achieved as several agencies with 200 employees continue rescue operations to bring out 41 workers trapped in the tunnel. After repeated interruptions in the auger machine, vertical drilling work has been started from the top of the hill from Sunday. And till now drilling up to 30 meters has been completed. Meanwhile, in a positive development, broken parts of the auger machine have been taken out. Now manual drilling work will be started here, which will proceed under the supervision of the engineering group of the Indian Army, Madras Sappers. The rat hole mining technique will be adopted for manual drilling, in which small tunnels are dug. Such tunnels are made in coal mines. Former PMO advisor Bhaskar Khulbe and PMO Deputy Secretary Mangesh Ghildiyal have reached the Silkyara tunnel site to take stock of the situation. General VK Singh (retired) also reached the site where he offered prayers in the temple of Baba Bokh Naag Devta built outside the tunnel. Two days ago, the Meteorological Department had issued a yellow alert for three days. Light snowfall has also started in Uttarkashi, which may hamper the rescue operation. Recently, Chief Minister Pushkar Singh Dhami met the family of Pushkar Singh Airi, a worker from Tanakpur, who is one of the 41 workers trapped in the tunnel. During the meeting, Dhami consoled the family members. He also said that the rescue work will be completed soon and all the workers will come out soon. /IANS