Himachal tunnel collapse: Rescue work halted again
Exactly a week after three workers of the Himalayan Construction Company were trapped inside an under-construction tunnel of the Kiratpur- Nerchowk four lane project when its roof collapsed, 20 km from Bilaspur town of Himachal Pradesh, the authorities have extended the deadline to rescue them as the drilling rig being used to bore a pathway has encountered problems.chandigarh Updated: Sep 20, 2015 07:17 IST
The ongoing rescue operation to winch up two workers trapped in an under-construction tunnel at Tihra village near Bilaspur was halted again late on Saturday evening as the heavy duty hydraulic rig developed a snag. The rescuers had earlier informed that they had reached the roof of the tunnel after digging up to 39 meters and were about the begin last phase of the rescue operation.
The rescuers said they needed to dig two meters more to reach the iron ribs on the roof of the tunnel.
“The hydraulic pipe in the rig has developed a snag. We are uncertain about how much time it will take to replace it,” said Bilaspur deputy commissioner Mansi Sahay Thakur.
Earlier in the day, the rescuers reached near the arch of the tunnel after digging a 39-metre vertical cavity. Three workers of Himalayan Construction Company were trapped in tunnel number 4 of the Kiratpur-Manali four-lane project when a part of it collapsed a week ago.
Rescuers were able to establish contact with two of them, Satish Tomar and Mani Ram, by drilling a 47-metre vertical communication channel into the tunnel three days after the disaster struck. The whereabouts of the third worker, Hirday Ram, are not known.
“The rig reached the arch of the tunnel after 39 metres of vertical drilling and now the rescuers have started the work to insert steel pipe casings,” said Bilaspur deputy commissioner Mansi Sahay Thakur.
A rescuer will be lowered into the cavity in a caged capsule with cutting tools to cut down the ribs used in tunnel construction. Rescuers would not be able to reach the trapped workers without getting rid of the steel ribs, she added. “This will be a time-consuming process. We are not certain how thick this part is and the time it will take to cut down the ribs,” she said.
Of the 1.2-km proposed tunnel, 275 metres was excavated when the disaster struck last week. The tunnel caved in around 80 metre from the opening and it is estimated that the debris has filled the tunnel up to 130 metres. Beyond that again is a cavity and this is the part where the workers are trapped.
Rescuers from National Disaster Response Force (NDRF) and Border Road Organisation (BRO) are stationed at the site for the next part of the operation. “As soon as the pipe casing is done, the rescuers will start cutting the ribs,” Thakur said.
‘Food, water being supplied’
The authorities got in touch with two workers on Wednesday after drilling a hole horizontally into the tunnel and sending in thermal cameras.
The authorities have since been supplying food, water, and oxygen for the two labourers twice a day through a vertical 47-m pipe with a diameter of 4 inches.
On Saturday morning, Thakur said khichdi, glucose, dry fruits and water were sent through the pipe. Packets of oral rehydration solution (ORS) to keep the workers hydrated were also supplied. A doctor and a psychologist were also at the site to talk to the trapped workers.
Workers Satish Tomar and Mani Ram have kept their morale high and look confident.
When Bilaspur deputy commissioner talked to them on Saturday morning, Satish seemed concerned about his family and told the officer to convey to the family that he was fine and would see them soon.
The trapped workers are being spoken to with the help of a remote camera and microphone lowered into the communication channel. “We are all with you. You need not worry. Your family is awaiting your early rescue. I will personally convey your message to them,” Thakur told Satish.
Medical team ready for job
Dr Arvind Chopra, who is overseeing the medical assistance in the rescue operation, told HT that as soon as the workers would be pulled out, the doctors would do all medical examination at the spot depending on their condition.
“We will check them for blood pressure, oxygen carrying capacity of their blood, sugar level apart from pulse examination. We have also brought blankets and will give it to them if their body temperature is found below normal,” said Dr Arvind.
Living in dark for long can have psychological effect on a person. However, if they are acclimatised to such conditions, there is a rare chance of it, he added.
Dr Arvind said, “We will allow a family member to meet them and they will be taken to hospital as some more medical examination will be needed.”
The tunnel collapse
The proposed length of under construction tunnel: 1.2 km
Length of tunnel dug so far: 275 metre
Distance of cave-in from the mouth of tunnel: 80 metre
Debris spread over inside tunnel: 50 metre
Two workers who are alive are trapped beyond 130 metre from the mouth
The vertical distance between roof of tunnel and top mountain surface: 47 metre
The distance drilled so far: 39 metre
Diameter of the drilled hole: 1.2 metre
The authorities had drilled a four-inch diameter vertical hole (47 metre) early this week and used it to lower communication equipment, camera to reach out to the trapped workers and are using it for supplying water and food
Drilling of second vertical hole of bigger diameter to winch up the workers is underway
How were the trapped workers located?
After three workers were trapped in a tunnel on September 12 (Saturday), the rescuers tried to remove the debris manually by using earthmovers. As it didn’t work, a large drilling machine, usually used in tunnel construction in the hilly area, was taken uphill to drill a vertical cavity on the third day. After two days of continuous efforts, the rescuers were able to drill a 47- meter vertical cavity into the tunnel and pipe was inserted into it on Wednesday. Contact was established with the two trapped workers — Satish Tomar and Mani Ram — after a remote camera and microphone were lowered into the cavity. Since then, rescuers are in continuous touch with the duo and talk to them at regular intervals.
Who is in charge of the rescue operation?
Project director of the Himalayan Construction Company Gurmeet Singh is overseeing the operation under the supervision of RS Rao of Border Roads organisation (BRO), who is heading the Rohtang tunnel project. Gurmeet said the company had also sought help of two European consultants who are experts in tunnel projects in mountainous region.
When was the rig brought in from Jaipur?
The rig was brought to the site on September 18 (Saturday) after the rescuers decided to dig a vertical cavity to bring out the trapped workers. The heavy duty hydraulic machine was taken uphill and drilling. For the initial 24 hours, the rescuers were able to dig up to 28 metres of vertical cavity as strata were loose and dry. However, after 28 meters, the strata hardened and the machine was struck in a sedimentary rock, which engineers say, might have been formed by lava, after a volcanic eruption many years ago. This has slowed down the drilling work. The real challenge lies when the cavity reaches the arch of the tunnel as the rescuers will have to cut down iron ribs laid to strengthen the tunnel roof.
When was the communication channel established?
The communication channel is being used to supply eatables, apart from communication with the trapped workers. The food is being provided to the trapped workers after consultation with doctors who are stationed near the site. “After establishing contact with the trapped workers, they were given juice, ORS, dry fruits and water. From second day, they are been given rice, and “khichdi”. On Friday, they were given some bananas and date palm,” said DrArvind Sharma, who is in-charge of the medical team. A psychologist has also been called in from the Bilaspur hospital for counselling the trapped workers.
What is the dimension of the rescue chute?
Round-the-clock vertical drilling is being done by heavy duty hydraulic rig to create a cavity to pull out the workers who are trapped in the tunnel. The 1,200 mm (1.2 meter) diameter cavity will be strengthened with the steel casing which is also being assembled near the drilling site. The casing will be done by inserting hard metal casing into the cavity to prevent fall of debris. After the cavity is strengthen, an NDRF member will be lowered into it the cavity who will cut iron ribs used in the tunnel construction. It is only after cutting the ribs that the rescuers will be able to reach the workers.