Debswana adopts OREP to extend Orapa

MBONGENI MGUNI
Staff Writer | Tuesday June 15, 2010 00:00

 

The resource at Orapa is expected to run out in 2026 after more than half a century of high value diamond production and pivotal support to the country's economic development. However, under the Orapa Resource Extension Project (OREP), geologists and strategists at Debswana hope to tap into resources below the current level being mined.

Last week, Orapa geologists explained that drilling under Phase 2 would take place at Cut 3 phase, or at depths between 265 and 475 metres below surface. Drilling studies will enable geologists to estimate and later determine the amount of diamonds below the current mining level, which will inform the feasibility of expanding the mine and the method of extraction to be used.

A similar exercise was conducted at Jwaneng under the Jwaneng Resource Extension Project (JREP), the results of which are driving the multi-billion Cut 8 project. Quoted in Orapa Weekly, the Manager of Debswana Geological Evaluation Projects, Benjamin Letsatle, said Phase 2 of the OREP was due to start and that it would involve 16, 500 metres of drilling samples.

OREP Phase 1 ran from 2006 to 2008, involving 38, 500 metres of drill core. Phase 2 should have begun last year, but was postponed due to the negative impact of the global recession on Debswana and the diamond industry in general.

'(Under Phase 2), this core will be primarily sampled for diamond grade information to allow us to predict the value of the resource at depths beneath which we are currently mining,' Letsatle told Orapa Weekly.

'A key output from OREP Phase 1 has demonstrated that the nature of the ore at depth is quite different to that which we have mined for the past 40 years. So, it is important for us to understand if the grade is also changing.'

It is expected that after OREP Phase 2, Debswana strategists will have information on the grade, volume, density and value of diamonds beneath the current level being mined at Orapa.

'The information collected by this programme will allow the mine to start planning for life beyond Cut 3, which is another example of Mine Resource Management shaping the future of mining at Orapa,' said Letsatle.

Should Orapa's expansion proceed as Debswana did at Jwaneng, resource estimation beneath the current mining level would pave way for feasibility studies to identify the mining process, treatment and other technical requirements.

Importantly, an element called strip ratio will determine whether Debswana should go underground to tap into the resource, or expand the existing pit. Strip ratio refers to the amount of ore and the cost of extracting it when compared to the amount of diamonds recovered from treating this ore.  At Jwaneng, strip ratio and other results of the feasibility study favoured expansion of the pit rather than establishing underground mining activities.

Meanwhile, Debswana is preparing for the closure of Letlhakane Mine whose decommissioning is scheduled for 2014. According to Orapa Weekly, work is accelerating on the Preliminary Mine Closure Plan which, by law, has to be completed five years prior to mine closure.

Orapa and Letlhakane Mine Closure Project leader, Lebesani Mashabile, was quoted by Orapa Weekly as saying the mine closure project aimed to ameliorate the negative, social, economic and environmental impact of the closure on the community.

While closure plans are submitted to Government at the inception of mining activities, these are continually updated and a final decommissioning plan issued. The mine closure project will involve extensive consultation with various stakeholders, including employees and the community. Feedback from this, will guide Debswana on how to implement closure of the mine.

Orapa Mine's operations are expected to end in 2026 while Damtshaa's will end between 2014 and 2023. Closure of Orapa-Letlhakane Mines will have a devastating impact on schools, hospitals and the livelihoods of thousands of residents and business owners reliant on the mine.