https://padlet.com/zev_jagalur/mtj9nzg0ovnh Made with ♥ en-us 2016-12-23 02:35:21 UTC 2025-10-08 06:35:42 UTC hello@padlet.com zev_jagalur https://padlet.com/zev_jagalur/mtj9nzg0ovnh/wish/144725224 This film was very interesting. It is about how a mine in Chile collapses and there are 33 men trapped. There is about half a mile of the hardest rock between the miners and the surface. There were in fact three separate drilling operations.
    On August 5, 2010, in the San Jose mine in Northern Chile, there was a terrible collapse. The 33 missing were originally feared dead, since nobody knew they were alive deep under the surface. Some early rescue attempts failed because the path was blocked. They tried to drill 6 inch holes into the tunnels below the collapsed section to make contact. They brought in big rigs with diamond drilling bits.  The high speed drills can drift off course. The engineers had to reduce the error rate in order to reach the deep refuge where they thought the miners might be. On the 17th day they had almost given up hope. The rigs were ordered to start shutting down. Then someone heard something.  Also, there was a note strapped onto the end of the drill bit. The 33 miners were alive !  
    Now the question was how to reach them. They were about half a mile down. They made 6 inch holes to supply provisions. The miners had survived because the leader had made them ration food. They only had one sup of milk and one spoon of tuna every 2 days. The medics first sent a glucose solution. The Strata 950 arrived. It had 3 rotating tungsten steel discs. It needed a lot of water to cool the bit on a constant basis. The American rig arrived - the SRAM t135.  Plan B was that instead of grinding the rock, the drill would smash it. This drill head was made of hardened tungsten steel points. It would hammer into rock 20 times a second. It was twice as fast as the Strata 950. At one point thouth, after 879 feet, the drill broke when it hit an iron roof bolt. Plan B was temporarily dead because they had to retrieve broken metal which was blocking the way. 
    Plan C was a monster new drill. It used land the size of a football field. 
    Plan B started working again. They got through to the access tunnel. Now they had to widen it from 12 to 28 inches. They used a new drill head which was USA made. Brandon Fisher's specially designed drill worked. They got through. There was a risk of collapse at the final stages. The miners were winched up, one by one, in a capsule vehicle which was specially made. 
It is amazing that they survived such an ordeal. It is equally amazing that the technology exists to cut through hard rock to such depths.    ]]> 2016-12-23 02:49:24 UTC https://padlet.com/zev_jagalur/mtj9nzg0ovnh/wish/144725224