The $220-million recapitalisation of AngloGold Ashanti's Obuasi mine, in Ghana, is expected to lead to significant improvements over the next four years, a spokesperson tells Mining Weekly. Currently, Obuasi mines down to 1 500 m or 50 level.
Production at the mine has been hampered by a lack of capital investment during the last five years.
Since the merger of AngloGold and Ashanti last year, efforts have been concentrated on tackling poor equipment availability and a shortage of developed reserves as well as on infrastructure development.
Several steps are being taken to deal with these shortcomings and to modernise the operations above 50 level.
New trackless-mining equipment is being commissioned underground. Underground workshops have been upgraded, while the size of the underground fleet has been reduced to enhance efficiency.
To tackle the shortage of developed reserves, the development contractor has been provided with refurbished equipment and is involved in mine-planning and review processes, says the spokesperson, adding that the situation is monitored daily.
Underground access has been established between the central and southern parts of the mine, and this is expected to secure mining for the next three years.
A project team has been set up to review all aspects of ventilation and cooling, while AngloGold Ashanti's Johannesburg-based technical team is spending considerable time working with Obuasi management to improve infrastructure and productivity.
The recapitalisation of Obuasi is expected to lead to a $20/oz decrease in working costs over the next four years.
In 2003, the mine produced 513 163 oz at a cash cost of $217/oz.
The AngloGold Ashanti spokesperson says that $44-million has been budgeted over a four-year period for the Obuasi Deeps project, which is investigating the feasibility of taking mining below 50 level.
To date, 45 km of diamond-drilling has been completed in Central Deeps down to 67 level.
Drilling will now be concentrated on the northern part of the mine.
This will allow planning to start on phase one; a ramp system down to 60 level.
AngloGold Ashanti plans to drill two surface longholes down to 100 level (3 000 m) this year.
This is intended to give certainty on the continuity of mineralisation and geological structure down to this depth.
The holes are expected to take 12 months to complete, and the inform-ation gained is intended to guide future drilling.
If it is confirmed to be viable, it is expected that Obuasi Deeps will come on stream in 2015.