/C O R R E C T I O N From Source -- Rockwell Diamonds Inc./

Please note that the headline of c7141 sent at 8:30 ET has been revised. Correct copy follows:

Rockwell announces positive Preliminary Economic Assessment for Wouterspan property

VANCOUVER, May 15, 2013 /CNW/ - Rockwell Diamonds Inc. ("Rockwell" or the "Company") (TSX: RDI; JSE: RDI) is pleased to announce that it has updated a Preliminary Economic Assessment ("PEA") on its Wouterspan alluvial diamond property that is located on the opposite side of the Orange River from the Saxendrift diamond mine. The PEA was carried out by a team led by Dr Kurt Petersen, an expert diamond metallurgist and Walter Bold Pr. Eng. Rockwell's Group Engineer. There was also significant input from Paradigm Project Management ("PPM") a company with a strong track record in the innovative development of new diamond mines.  All currency values are stated in Canadian dollars unless otherwise indicated.

The study indicated positive economics, sufficient to take the project to the detailed design stage. The economic model yielded an internal rate of return of between 45% and 70% for a range of scenarios based on the key inputs. The net present value ("NPV") for the base case is $91.71 million at a 15% discount rate, yielding a project payback period of 2.3 years from the start of construction or approximately 1.3 years from commencement of production. The project is most sensitive to revenue with a 5% variance in the total revenue over the 10 year life of mine, impacting the NPV by 15%. The operation is expected to employ 300 people.

Key assumptions of the study

• A plant with a capacity of 1,200 tonnes per hour ('tph') (or 354,000m³ per month), a rate that lowers the sensitivity of diamond production to the nature of the resource being mined.
• A plant design comprising of three processing streams: two Bourevestnik Bulk X-ray systems such as those that have been successfully implemented by the Company at its Middle Orange River operations to handle the coarse and mid-sized gravels; and the third stream being a dense media separation (DMS) stream to process fine material.
• A reduced water consumption rate that is suited to the environmental conditions in the Middle Orange River region.
• The use of contract mining at a fixed unit cost that reduces the capital requirements and enables Rockwell to focus on mine planning and processing.

Summary of financial model and results

The net present values in the table above are shown pre tax and were calculated in ZAR before conversion into C$ at an exchange rate of ZAR8.50 / C$. These are also net of the mining royalty that has been applied according to the Mineral and Petroleum Resources Royalty Act No 28 of 2008 (the "Royalty Act").

A Preliminary Economic Assessment ('PEA') is preliminary in nature, and includes Inferred mineral resources that are considered too speculative geologically to have economic considerations applied to them that would enable them to be categorized as mineral reserves. However, the mine design aspects of the PEA were completed at a pre-feasibility study level as per standard industry practice. There is no assurance that the PEA will be realized.

Resource summary

Estimated mineral resources for the Wouterspan property are:

The effective date of the resource statement for Wouterspan is 30 November 2010. Further details of the estimate are provided in the Company's May 31, 2011 news release.

"Completion of this study on Wouterspan is a critical milestone in Rockwell's strategy to unlock the growth potential of its Middle Orange River projects. The property was successfully mined in the past using pan plants. We now have access to more efficient fit for purpose technologies such as the Bulk X-ray system that we have incorporated into the new plant design," explains James Campbell, CEO, Rockwell Diamonds. "The study's results are based on what we are achieving in other areas of our operations. The project capital is expected to be some $42 million, including a 25% contingency, with the potential to come in substantially lower. The team that conducted the Wouterspan study was instrumental in more than halving the eventual capital budget required to recently bringing on stream a new kimberlite mine in Botswana, compared to initial estimates."

"A key element of Rockwell's strategy is to process 500,000m³ per month of high quality gravels from the Middle Orange River region. Our Saxendrift and Saxendrift Hill Complex will collectively process 250,000m³ per month," elaborates Campbell. "We recently announced our plans to bring the Niewejaarskraal mine into production at a processing capacity of 115,000m³. We are now considering taking the Wouterspan property to the next step. This will enable us to achieve our full strategy in the Middle Orange."

Commenting on the potential socio-economic benefits of the project, Campbell added that: "While the construction of a new mine at Wouterspan would add significant positive impacts to the local economy, we also project the creation of some 300 new jobs in this region which is troubled by high levels of unemployment. The plant design is based on continuous operations, running four shifts per day. This means that Wouterspan's job creation potential is over and above the 93 jobs that were recently created at our Saxendrift Hill Complex mine, which is currently being commissioned."

Mr Glenn A Norton (Pr. Sci. Nat.), Group Technical Manager and Walter Bold (Pr. Eng (Mech)), Group Engineer, who are both employees of Rockwell supervised the PEA and have reviewed and approved the contents of this release. Further details will be provided in a technical report that will be filed on the Company's profile at www.sedar.com.

About Rockwell Diamonds:

Rockwell is engaged in the business of operating and developing alluvial diamond deposits, with a goal to become a mid-tier diamond production company. The Company has two operational mines, which it is progressively optimizing, as well as a third mine which will come into production in the first quarter of 2013. Rockwell also has two development projects and a pipeline of earlier stage properties with future development potential. The operations are based on high throughput processing capability and Saxendrift, the flagship mine has among the lowest unit costs in the industry, as a result of implementing fit for purpose technologies.

The Company is known for producing large, high quality gem stone diamonds comprising a major portion of its diamond recoveries and has a beneficiation joint venture that enables it to participate in the profits on the sale of the polished diamonds.

Rockwell also evaluates merger and acquisition opportunities which have the potential to expand its mineral resources and production profile and would provide accretive value to the Company.

No regulatory authority has approved or disapproved the information contained in this news release.
Forward Looking Statements
Except for statements of historical fact, this news release contains certain "forward-looking information" within the meaning of applicable securities law. Forward-looking information is frequently characterized by words such as "plan", "expect", "project", "intend", "believe", "anticipate", "estimate" and other similar words, or statements that certain events or conditions "may" or "will" occur. Although the Company believes the expectations expressed in such forward-looking statements are based on reasonable assumptions, such statements are not guarantees of future performance and actual results or developments may differ materially from those in the forward-looking statements.

Factors that could cause actual results to differ materially from those in forward-looking statements include uncertainties and costs related to exploration and development activities, such as those related to determining whether mineral resources exist on a property; uncertainties related to expected production rates, timing of production and cash and total costs of production and milling; uncertainties related to the ability to obtain necessary licenses, permits, electricity, surface rights and title for development projects; operating and technical difficulties in connection with mining development activities; uncertainties related to the accuracy of our mineral resource estimates and our estimates of future production and future cash and total costs of production and diminishing quantities or grades of mineral resources; uncertainties related to unexpected judicial or regulatory procedures or changes in, and the effects of, the laws, regulations and government policies affecting our mining operations; changes in general economic conditions, the financial markets and the demand and market price for mineral commodities such and diesel fuel, steel, concrete, electricity, and other forms of energy, mining equipment, and fluctuations in exchange rates, particularly with respect to the value of the US dollar, Canadian dollar and South African Rand; changes in accounting policies and methods that we use to report our financial condition, including uncertainties associated with critical accounting assumptions and estimates; environmental issues and liabilities associated with mining and processing; geopolitical uncertainty and political and economic instability in countries in which we operate; and labour strikes, work stoppages, or other interruptions to, or difficulties in, the employment of labour in markets in which we operate our mines, or environmental hazards, industrial accidents or other events or occurrences, including third party interference that interrupt operation of our mines or development projects.

For further information on Rockwell, Investors should review Rockwell's home jurisdiction filings that are available at www.sedar.com.

Information Concerning Estimates of Indicated and Inferred Resources
This news release also uses the terms 'indicated resources' and 'inferred resources'. Rockwell Diamonds Inc advises investors that although these terms are recognized and required by Canadian regulations (under National Instrument 43-101 Standards of Disclosure for Mineral Projects), the U.S. Securities and Exchange Commission does not recognize them. Investors are cautioned not to assume that any part or all of the mineral deposits in these categories will ever be converted into reserves. In addition, 'inferred resources' have a great amount of uncertainty as to their existence, and economic and legal feasibility. It cannot be assumed that all or any part of an Inferred Mineral Resource will ever be upgraded to a higher category. Under Canadian rules, estimates of Inferred Mineral Resources may not form the basis of feasibility or pre-feasibility studies, or economic studies except for Preliminary Assessment as defined under 43-101. Investors are cautioned not to assume that part or all of an inferred resource exists, or is economically or legally mineable.

SOURCE Rockwell Diamonds Inc.