TORONTO (miningweekly.com) – Despite a 22% drop in grade, compounded by a 35% slide in realised prices, Southern Africa-focused diamond miner Rockwell Diamonds reported record diamond sales revenue of $15.8-million for the fiscal third quarter ended November 30, boosted by a 127% increase in carats sold.
The Vancouver-headquartered miner said prices during the period were impacted as a result of recovering fewer large precious gems from its operations located in South Africa’s Middle Orange River (MOR) region.
Rockwell, which has shares listed on the TSX and the JSE, said it had managed to lift the mined gravel volumes at its Saxendrift operation by 62% year-over-year, to average 180 000 m3 in the three months.
The company processed lower grades at the traditional Saxendrift mining area, now in the second half of its mine plan, and said that the remaining mining areas would require higher stripping ratios. Accordingly, gravel volumes processed increased 21%, but carat output declined 29%. The operation did, however, recover eight stones larger than 20 ct.
At the Saxendrift Hill Complex (SHC), the company lifted the volumes of mined gravel and processed by 46% and 3% over the same period of fiscal 2014, respectively. As a result of ongoing exploration, SHC's mine life had been extended into 2015.
Rockwell had implemented an earthmoving vehicle renewal plan at Saxendrift and SHC, which helped the complex process a record 1.5-million cubic metres of gravel.
Year-on-year carat output, despite being on plan, declined 63% owing to the exceptional recoveries in the previous year. SHC's bulk X-ray processing plant operated at its nameplate capacity of 80 000 m3/m throughout the third quarter, and recovered a 68 ct rough diamond, among other notable stones.
Further, Rockwell’s Niewejaarskraal operation ramped up mining by 68% and processing by 92% year-over-year. Towards the end of the quarter, the plant’s monthly capacity rose to 120 000 m3 with modifications to the front-end in-field screen.
This resulted in carat output increasing nearly threefold, underpinned by higher volumes and grades, which increased to 0.54 ct/100 m3, in line with the average grade for the mine.
Notable stones included five stones exceeding 20 ct, the largest of which weighed 68.6 ct.
The company continued with its royalty contractor-mining programme at Tirisano and in joint venture at Kwartelspan, which continued to deliver positive results, with volumes of gravel processed up 98% and carat output up 59% for the third quarter.
“Our production and sales performance continues to improve with record volumes of both gravel mined and processed and carat sales from the MOR in the third quarter. A highlight for the quarter was bedding down of the earthmoving vehicle renewal plan and ongoing optimisation of our in-field screens that helped us post a 60% increase in mining volumes and 47% increase in gravel processed. The increase in volumes processed offset the lower grades and lower prices achieved for the rough product,” president and CEO James Campbell said.