JOHANNESBURG (miningweekly.com) – Paragon Diamonds has completed a high-level scoping study at its prospective Lemphane operation, in Lesotho, which outlined the expectation for a ten-year openpit mine.

The mine life included a six-month trial mining phase of 100 000 t with a 12- to 18-month construction period, followed by mining at a rate of 1.5-million tons a year for two years and full-scale production of three-million tons a year for a further eight years.

The study was based on openpit mining of some 27-million tons of kimberlite to a depth of 280 m below the surface with a waste-to-ore ratio of 1.3:1.

Total mining costs were calculated at $15/t.

“The drilling is progressing as planned and we look forward to bringing the plant up to full capacity and updating the market on the bulk sampling and eventual trial mining programme over the coming months," Paragon chairperson Martin Doyle said in an operational update on Wednesday.

Further, the company had prepared a mining lease application in accordance with the Mines and Minerals Act, which it said had been submitted to and acknowledged by the Lesotho Ministry of Mines.

Meanwhile, drilling continued, with the first two holes intersecting kimberlite at 280 m and 370 m respectively, indicating that the wall rock contacts tapered at between 82° and 85°, in line with projections.

Some 775 m of kimberlite had been drilled, to date, with over 2 000 m of drilling planned for the initial stage.

In anticipation of undertaking trial mining of 100 000 t of material in the second half of 2013, stripping had started over the central portion of the Lemphane kimberlite.

A corridor 100 m wide and 250 m long was being stripped of up to 12 m of top soil and basalt debris to expose surface kimberlite for subsequent mining, while over 10 000 t of material had been removed and stockpiled outside the pit perimeter.

Paragon reported that the water pipeline installed at the beginning of the year was performing well and was capable of pumping 500 m³/d of water to the process plant.

Bulk sample processing continued at a rate of between 800 t and 1 000 t a week, with processing of the outstanding 15 000 t of sample to be completed by June 2013.