The miner attributed the positive growth to operational turnaround of the company and its core focus on the Middle Orange River (MOR) Region of South Africa.

During the fiscal 2014, the company processed gravel volumes of 3,761,062m3, an increase of 28%, comprising 2,662,901m3 from own operations, and the remainder processed by the royalty mining contractors.

Rockwell witnessed a 6% grade improvement across its properties, driving a 27% increase in total carat production, that includes 14,222 carats from own operations and 13,554 carats from contractors.

Rockwell CEO and president James Campbell said that the improvements have been consistent each quarter over the last two years, as the company has now reported seven consecutive quarters of dollar denominated revenue growth.

"Rockwell reported an operating margin before amortization and depreciation of $6.0 million, compared to $1.1 million in the prior year. Economies of scale as a result of operating exclusively in the MOR also emerged, as production costs for the year increased 25% to $39.2 million, against the 52% improvement in the value of diamond sales," added Campbell.

Volumes processed from Rockwell’s three MOR mines reported year-on-year growth of 46%, with a 12% increase in average grade and carat production up 63% in the region compared to fiscal 2013.

"Looking forward, we remain firmly focussed on our medium term target to process 500,000m3 per month of quality gravels. We are conducting contiguous exploration of existing resources at the Saxendrift Extension property to increase the current life of mine, further leveraging our invested mining infrastructure at Saxendrift. We also have a focused exploration and trial mining programme at SHC to maximize the resource potential and develop contiguous areas," added Campbell.