It took nearly 23 hours to bring all 33 miners to the surface..
The world has been captivated by the rescue of 33 miners trapped 688 metres underground in the San Jose mine near Copiapo in northern Chile.
The entrance to the main tunnel collapsed on 5 August 2010, trapping the miners – 32 Chileans and one Bolivian – deep underground for over two months.
A breakthrough in October saw a rescue shaft finally reaching the miners, enabling workers to start bringing them to the surface one by one. The rescue capsule, named Phoenix, was fitted with an oxygen supply and communications facilities, and took about an hour to make a round trip. It brought the last miner up in the early hours of 14 October.
This rescue was made possible by the efforts of South African construction and engineering company Murray & Roberts through its Cementation division, Cementation’s Chilean partner Terraservice, and others.
Cementation is the engineering giant’s global mining contracting division, and is collaborating with Terraservice in a joint venture called Terracem. Murray & Roberts have been involved in many major construction projects around the world, including the Burj al Arab in Dubai, the Cape Town stadium, and the Paris-Sorbonne University in Abu Dhabi.
It was a Terraservice drill that reached the miners’ underground chamber on 22 August 2010, allowing them to attach a written message to the drill pipe confirming they were alive and well. Food, water and medication were sent down to the men through this shaft.
Murray & Roberts were the first to get a drill to the site in response to the Chilean government’s call for help. Terracem dispatched one of their raise drilling machines, the Strata 950, to San Jose to begin drilling a pilot hole to reach the miners.
This machine, which is owned by Cementation Canada and operated in Chile by Terracem, had just sunk a shaft for the nearby Andina mine and could begin drilling immediately, even though the rock was hard, which necessitated frequent interchanging of drill heads.
Murray & Roberts co-developed the rotary vertical drilling system used by the Strata 950. The pilot shaft was just 370mm wide, but was later reamed to its final diameter of 750mm, allowing for the reinforcement and stabilisation of the top section with steel casing.
Three drilling operations, running concurrently, raced to be the first to reach the trapped men. The Strata 950 was plan A, and plans B and C involved a Schramm T-130 drill and a Rig 421 oil well drill respectively.
It was the plan B hole that was finally used to extract the miners, who have become national heroes and were lauded by the world for their determination to survive.
Murray & Roberts group communications head Ed Jardim said in a statement: “This is a wonderful achievement for South Africa and Murray & Roberts. We are very privileged to have been a part of this process and it is a feather in our cap as South Africans – as leaders in underground mining.”
The first miner, Florencio Avalos, reached the surface just after 05h00 South African time on 13 October, and the last to be lifted to safety was Luiz Urzua, who was shift chief when the incident happened. The rescue took 22 hours and 37 minutes.
Jardim added: “The Chilean government has managed the rescue and drilling process exceptionally well and we have been proud to have assisted them through this process.