How The Trapped Miners in Chile Will be Rescued
This is an article about the options that the Chile collapsed mine rescuers have as they try to hoist the miners.
On August 22, 2010, a retrieval mission quickly turned into a rescue mission when trapped miners tied a note to a drill that was probing a collapsed mine in Atacama, Chile. This was a pleasant surprise; a modern day miracle that set rescue teams into action.
Engineers, rescuers, government agencies and international experts were locked up in meetings at the site of the collapse and beyond, trying to draw up plans of action and evaluate all the available options of getting the miners out without any further delay.
First and foremost, there were three-6cm wide- drill holes that were initiated in order to get the trapped miners connected to the outside world. The first was the purpose of aiding in communication. Rescuers above the ground needed to find out more about the conditions below. The second drill hole has been likened to the umbilical cord because the miners are being sent food, water and medication through this hole and the third is for ventilation purposes.
The rescue team devised what came to be known as plan A. This was the starting point in the rescue process; Later on, two more plans (plan B and C) would be developed along the way. The rescue team decided that it was important to have a number of plans going in order to avoid disappointments. It would be heartbreaking to go all the way only to realize that the plan is not feasible and so send the team back to step one.
Plan A involves drilling directly above the shelter where the miners are trapped .A Strata 960 water drill is being used for this plan. The distance to be covered by the drill is 700m.The plan entails drilling a 13-inch pilot hole. The hole will then be doubled in width using a special drill. The rescuers must exercise utmost precaution lest they cause another collapse right above the miners. A rescue capsule will then be lowered through the man-hole and it will be used to hoist the miners one at a time.
Plan B is the fastest. It involves digging towards where the miners are trapped, at an angle. This is commonly referred to as an inclined vertical shaft. However, it will not lead the rescuers directly to where the miners are trapped but to an adjacent shelter believed to have been used as a workshop by the miners before the collapse. A T-130 drill will be used for this rescue plan. The distance to be covered is rather shorter at 640 Meters.
Plan C will cover the shortest distance of only 600m. An oil drill will be used to reach the miners. However, the hardest part is setting up the drill. It took more than a month to get the oil drill up and ready.
All the three plans are being carried out concurrently as the rescuers try to reach the trapped miners from three different directions. The geology of the Atacama desert is relatively unstable. Therefore, the drilling can not be rushed. Because of the poor quality of the bedrock, a steel sleeve (culvert) will be required. Installing the sleeve is a very delicate process otherwise it would lead to another collapse.
The trapped miners are also expected to join in their own rescue as they clear debris that will be falling from the drilling process. Another reason, why the drilling should be slow is to prevent the hole from deviating and not hitting the target. This is normal in all forms of mining.
This is not the first time that such a rescue procedure will be carried out. The technique of pulling out trapped miners through a man-hole was successfully tried in 1963 in Pennsylvania where 2 miners were pulled out of a collapsed coal mine.
The final rescue will be carried out at night in order to protect the miners from the sun’s light. It will take approximately one and a half hours (1 ½ hrs) to pull up each of the 33 miners over the distance of 700m. That translates to more than 2 days before the last miner is rescued. It might take a single day if all the 3 plans will be working at once. Of course the sickest and weakest of the miners will be pulled up first and the strongest will come out last. However, it has been subject of debate on whether the most technical and most qualified miners should come out first or last. Either way, every one of them who makes it to the surface will be celebrated by humanity.