JOHANNESBURG (miningweekly.com) – The plan to save the 33 Chilean mineworkers trapped 688 m from the surface in a space no bigger than a sitting room, was not a “guaranteed process”, said Murray & Roberts CE Brian Bruce on Thursday.

One of the 108-year-old company’s subsidiaries, Cementation, was working to free the miners, trapped since August 5, at the San José gold and copper mine, near Copaipó.

“Our network is intensely involved in finding solutions,” noted Bruce.

He said that Murray & Roberts was using “experience in a hundred years of deep-level mining in South Africa” to save the miners.

As a mining contractor, with vast experience in shaft-sinking, Cementation was also active in South America.

Murray & Roberts Cementation MD Henry Laas told Engineering News Online that there was not sufficient time to establish access to the miners by “conventional means”.

He said that specialised machinery, which could drill down to the required depth, was already on site.

“We are thinking to drill down to the trapped miners, and to then ream it to a diameter hole of around 700 mm. We can then use this shaft to hoist people to the surface.”

However, Laas warned that this was only the concept as it currently stood, and that there was still “lots of design work” under way, and “lots of options to consider”.

“We are still looking at the risks in establishing the holes, and then the design required for a hoisting solution.”

Laas noted that if this option presented itself as the preferred solution, it would take “three to four months” before the miners could be freed.

He said that South Africans would be responsible for the drilling this rescue shaft, as they had just completed shaft construction at another mine in Chile.

Three small shafts had already been established to the miners, namely for provisions, communication and ventilation.

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