Ventilation underground is a critical constituent of mining, and the construction of a new ventilation shaft can be extremely complex.
Murray & Roberts Cementation is completing a massive ventilation shaft installation project for Aquarius Platinum. The entire project consists of three separate phases, in which Murray & Roberts Cementation has been involved since the project’s conception.
Phase 1 began three years ago, and involved the installation of nine ventilation shafts at Aquarius’s Kroondal mine on the western limb of the Bushveld Complex.
The project took seven months to complete and was a “complete success”.
Phase 2 consists of a drilling of a further 13 ventilation shafts at Aquarius’ Kroondal and Marikana Mines and MRC was again contracted by Aquarius because of the successful completion of phase 1 – this project started in September 2006.
“Murray & Roberts Cementation’s ability to establish and maintain excellent client relationships, meet production targets and stay up to date with the latest technological developments in the drilling field is a reputation Murray & Roberts Cementation prides itself in,” says Purves.
The company’s expertise and drilling project portfolio extends beyond South African borders. It has completed two big ventilation shafts in AngloGold Ashanti’s Cuibá gold mine in Brazil.
“The ventilation shafts are the biggest holes in the whole of South America,” says Oosthuizen.
The project was completed in July 2006, and is a big contributor in enabling AngloGold Ashanti to increase gold production.
Following completion of the project, total air supplied was raised from 400m³/s to 720m³/s.
The project came as a result of AngloGold Ashanti’s need to start mining at deeper levels.
Opening up new ventilation ducts to penetrate clean air into the mine was the only hindrance to extending the mine to new depths, says Cuibá geologist, Paulo de Tarso.
Between 2006 and 2010, the mine will be extended from level 11 (800m deep) to level 21 (1,400m deep).
The first shaft will be used to send clean air into the new area, and the second shaft will serve to remove polluted air from underground.
The project commenced as two pilot holes, which were completed in December 2005. Reaming of the holes began last January.
Shaft sizes have an accuracy level of 0.15% and the entire process was completely injury-free.
“Despite the underground rock in Brazil being extremely prone to deflection”, says Oosthuizen, “Murray & Roberts Cementation was still able to complete the project on time.”
Murray & Roberts Cementation is already present in Zambia, Tanzania and Botswana, and is looking at Ghana, says Oosthuizen.
It has also completed various projects in Chile during the last seven years in a number of copper and gold mines.
Murray & Roberts Cementation will start another three ventilation shaft drilling projects at Anglo Platinum’s Townlands mine. Work is due to start in March.