The road outside the tunnel, which became uneven due to regular movement of heavy vehicles over the past fortnight was being repaired and a fresh layer of soil was being laid for smooth movement of ambulances.
Senior police officers briefed the security personnel outside the tunnel to spring into action the moment workers start coming out of the escape passage being prepared for them.
Pipes have been inserted up to 52 metres through the rubble at Silkyara tunnel, Uttarakhand Chief Minister Pushkar Singh Dhami said on Tuesday as efforts to rescue the 41 workers trapped there continued for the 17th day.
The breakthrough point is 57 metres, he told reporters in Silkyara.
Rescuers need to dig through around 10 metres of rubble using rat-hole mining technique to bring out the workers. This drilling was earlier carried out by a huge auger machine that got stuck in the rubble on Friday at around 47 metres.
A skilled team of workers began removing the muck by hand using the rat-hole mining technique on Monday while 800-mm diameter pipes were being pushed through the rubble by an auger machine.
"Pipe has gone in up to 52 metres. Earlier, it was at 51 metres. It was pushed one metre further in my presence. It will be pushed two metres more to 54 metres after which one more pipe will be laid," Dhami said.
When asked whether there were hurdles on the way, he said steel and iron girders were not being encountered. "Stones are coming in the way but they are being broken using cutters," the chief minister said.