TORONTO (miningweekly.com) – Toronto- and Johannesburg-listed Rockwell Diamonds had lifted diamond production for the second quarter ended August 31 by 14% year-on-year by processing 23% more gravel, despite a temporary mining suspension at its Tirisano operation.
The South Africa-focused diamond miner said production at the Saxendrift complex, located near the Middle Orange River, in South Africa’s Northern Cape province, including production from the newly acquired Jasper project had achieved a combined 26% year-on-year increase in volumes processed at 476 825 m3. This resulted in a 6% increase in diamond production to 1 996 ct.
The company noted that Saxendrift had, over the past two quarters, moved to processing lower-grade sandy gravels that made up most of the remaining resources. This required better mining efficiencies and in-pit screening to maintain a profitable production profile for this part of the greater Saxendrift, Saxendrift Hill and Jasper deposits.
The miner’s focus at the bulk X-ray plant was the reprocessing of recovery tailings as well as the implementation of continuous operations and optimising the materials preparation area, to convert the pilot sampling plant to meet the needs of a continuously operated production plant.
A grade of 2.5 ct per 100 m3 was achieved from processing 4 808 m3 of tailings material.
Initiatives to increase and extend the mine life of Rockwell's package of Middle Orange River properties and the associated operational footprint were ramping up and included introducing the Jasper project, Wouterspan project and Saxendrift Hill project into the operation.
Rockwell said the right-sizing strategy being implemented at the Orange-river located Tirisano project, since early July, saw mining operations put on hold and work concentrated on reconfiguring the processing circuit to rationalise the project.
The new wet front-end was commissioned early in the second quarter and had been integrated into the new processing plant, which would give it increased capability to process the clay-rich Tirisano gravels.
Volumes processed at Tirisano during the first six weeks of the quarter declined by 11% to 57 803 m3, with the 558 ct recovered being 8% lower on a year-on-year basis.
“Through the concerted efforts of Rockwell's executive and mine management teams, we quickly right-sized the Tirisano mine to adjust to the current diamond market, positioning it to provide positive returns,” Rockwell CEO James Campbell said in a production update.
The company said the plan was on track and Tirisano mining operations were scheduled to resume at a monthly mining rate of 50 000 m3 by the end of this month.
Further, the company’s Klipdam operation, also located in the Northern Cape, achieved a 27% year-on-year increase in volumes processed to 209 081 m3 for the second quarter. However, it fell short of the quarterly throughput target owing to continued plant and mining limitations.
Nevertheless, the mine's diamond production increased by 31% year-on-year to 2 274 ct as a result of an improved overall size distribution and quality from mining more of the paleaochannel gravels and primary Rooikoppie-material.
“At Klipdam, we were able to mine a better resource-area and the mine delivered a good operational performance. We still have some way to go in order to achieve our production targets, which is a high priority for Klipdam in coming months."
The company’s stock was priced at 28 Canadian cents apiece on the TSX on Wednesday morning.