LONDON, UNITED KINGDOM--(Marketwire - May 11, 2011) - Orsu Metals Corporation ("Orsu" or the "Company") (News - Market indicators)(AIM:OSU), the London-based precious and base metals exploration company, is pleased to announce updated pit-constrained mineral resource estimates for its Karchiga Volcanogenic Massive Sulphide ("VMS") copper deposit, northeast Kazakhstan (the "Karchiga Project"). The mineral resource estimates have been reported according to the Canadian Institute of Mining, Metallurgy and Petroleum Standards on Mineral Resources and Reserves (the "CIM Standards") and form part of the ongoing Definitive Feasibility Study ("DFS").

The updated mineral resource estimates (the "SRK 2011 Mineral Resource Estimates") have been prepared by the Company's lead DFS consultant SRK Consulting (UK) Limited ("SRK"), and relate only to the sulphide mineralisation in both the Central and North East lodes of the Karchiga deposit. SRK has constrained the reported Mineral Resources to material with reasonable prospects for economic extraction into two optimised open pits and by applying a cut-off grade of 0.3% copper. SRK's Indicated Mineral Resources are 7.1Mt of ore, grading 1.85% copper and containing 131,860t of copper metal, and the Inferred Mineral Resources are 1.2Mt of ore, grading 1.68% copper and containing 19,860t of copper metal.

The oxide mineral resource estimates in the Central lode remain unchanged from that which was previously reported by the Company (see technical report entitled "Updated Report on the Karchiga Property held by Orsu Metals Corporation, Kazakhstan" and dated March 22, 2010) ("WAI 2010 Estimate").

Mineralisation at Karchiga occurs in the Central and North East lodes. The VMS style of the mineralisation in both lodes is hosted along the contacts between the shallow dipping alternating amphibolite and quartz mica schist units. The two lodes have a strike length in excess of 1km and have been intersected down to depths of 200m below the surface. In the Central lode, the mineralisation is located within a series of shallow-dipping massive and disseminated sulphide bodies stacked at three stratigraphic levels and primarily consists of chalcopyrite-pyrrhotite and pyrite mineralisation. In the North East lode, the 2010 drilling results revealed the mineralisation, also primarily consisting of chalcopyrite-pyrrhotite and pyrite, to be located within two subparallel shallow-dipping and moderately folded massive and disseminated sulphide lenses, whereas it was previously thought that there was only one stratigraphic level of mineralisation.

SRK 2011 Mineral Resource Estimates

SRK has interpreted and wireframed a series of narrow mineralised lenses with varying dips in both the Central and North East lodes using a nominal 0.1%Cu cut-off. SRK has also constrained the reported Mineral Resources into two optimised open pits and by applying a cut-off grade of 0.3% copper. SRK's Indicated Mineral Resource so derived is 7.1Mt of ore, grading 1.85% copper and containing 131,860t of copper metal, and the Inferred Mineral Resource is 1.2Mt of ore, grading 1.68% copper and containing 19,860t of copper metal. Table 1 shows breakdown of the Mineral Resources for each lode and resource category.

The reported Mineral Resources are relatively insensitive to moderate changes in the cut-off grade up to 0.5% copper cut-off. In addition, the deposit contains gold which is recoverable, based on the metallurgical studies conducted as part of the DFS and reported by the Company in its press release dated April 28, 2011.

Whilst SRK used the same digital surface topography model and weathered horizon to distinguish the oxide from the sulphide as previously used in the WAI 2010 Estimate, the SRK 2011 Mineral Resource Estimates are also based on the recent in-fill drilling completed by Orsu in 2010 and an updated drillhole database, the integrity of which SRK has verified (see Orsu's press releases dated December 7, 2010 and February 10, 2011). Assays for the 2010 in-fill drilling programme have been completed for Cu, Zn, Pb, and Au in the laboratory of the Eastern Institute for Base Metals, based in Ust-Kamenogorsk, Eastern Kazakhstan, which is independent from Orsu and SRK. Standard, blank, and duplicate samples were inserted after approximately every 20 ordinary core samples. The ordinary half core samples have been taken from visually mineralised intervals and 5 m of visually unmineralised material below and above the mineralized intervals. The remaining half core samples are stored at the Orsu facility in Ust-Kamenogorsk, Kazakhstan. The SRK 2011 Mineral Resource Estimate has been derived using all data available at the end of April 2011 which SRK has reviewed and which SRK is confident is sufficient in terms of both quantity and quality to support the SRK 2011 Mineral Resource Estimates.

SRK produced new solid models (wireframes) constrained at 0.1%Cu cut-off grade and domaining for each individual mineralised zone and capped high copper grades where it considered this to be appropriate based on a statistical analysis of the available assay results.

A total of six domains have been modelled in the Central lode, three of which contained a separately modelled high grade zone, and three domains have been modelled in the North East lode. 3D wireframes were created from 2D sections which were spaced at a 25m interval in each of the Central and North East lodes. SRK and Orsu interpreted four post-mineral faults which run across the deposit and SRK used these faults as terminations to the mineralised domains. No more than 2m of waste has been included in the 2D sections used to produce the 3D wireframes.

The grade interpolation was carried out on 2m downhole composited drillhole samples selected within a hard boundary 0.1% Cu grade wireframe. Material types and samples data were subsequently extracted and subset within these discrete domains and grade interpolation was constrained to each individual domain separately.

SRK used a block size of 25m (X) by 25m (Y) by 5m (Z). Cu, Zn, Pb and Au grades were interpolated into the blocks using an Ordinary Kriging algorithm based upon the results of geostatistical modelling completed for the relevant sulphide data sets.

Specific gravity measurements were carried out for the different material types collected from Karchiga Diamond drill core and an in-situ bulk density value assigned to the block model based on the relationship between grade and bulk density below the weathered surface revealed by a regression analysis. Data from the Company's 2008 and 2010 drilling has enabled density regression plots to be established for the Central and North East lodes.

Table 2 shows the pit optimisation parameters that were used to define a pit outline which was then used to constrain the Mineral Resource to material with reasonable prospects for economic extraction. The slope angle parameters are the result of the geotechnical study undertaken by SRK. The Mining, Processing, and Operating Cost and the Net Smelter Return ("NSR") parameters have been taken from the technical report entitled "Preliminary Assessment of The Karchiga Copper Project, East Kazakhstan Region, Kazakhstan", dated May 25, 2010 and prepared by Micon International Co. Limited ("Micon 2010 Study"). A long term metal price of $2.95/lb Cu was assumed by SRK, in contrast to $3.00/lb Cu used in the Micon 2010 Study. Currently, no mineral reserve has been estimated as part of SRK's work, although a mineral reserve estimate is planned as part of the DFS on the basis of the SRK 2011 Mineral Resource Estimates.

Comparison with Previous Pit-Constrained Estimates

Table 3 shows a comparison between the SRK 2011 Mineral Resource Estimates and previously reported mineral resource estimates in the Micon 2010 Study, both pit-constrained. The cut-off grade of 0.34% copper used in the mineral resource estimates in the Micon 2010 Study was back-calculated based on the economic parameters used in the Micon 2010 Study and shown in Table 2 above. It should be noted that the SRK 2011 Mineral Resource Estimates are reported without dilution and loss while the mineral resource estimates contained in the Micon 2010 Study were reported allowing for 5% mining loss and 5% mining dilution.

The reported results are part of the ongoing DFS for the Karchiga Project the completion of which is expected by October 2011.

Dr Alexander Yakubchuk, COO and Director of Exploration of Orsu, commented: "While the SRK 2011 and the WAI/Micon 2010 Mineral Resource Estimates and Study were prepared using two different methodologies, especially in respect of the capping of the high grade assays, they have revealed comparable results which demonstrates once again the robustness of the Karchiga Mineral Resource. We are looking forward to completing a Mineral Reserve estimate for Karchiga as part of the DFS. The Company is pleased that the new Karchiga Project pit-constrained Mineral Resources have revealed an increase in both the resource tonnage and contained copper metal. This is expected to increase the life of mine to 11 years and reduce the stripping ratio, both of which are to be confirmed during the ongoing DFS."

FORWARD-LOOKING INFORMATION

This press release contains forward-looking information which is not comprised of historical facts. Forward-looking information involves risks, uncertainties and other factors that could cause actual events, results, performance and opportunities to differ materially from those expressed or implied by such forward-looking information. Forward-looking information contained (or referred to) in this press release includes, but may not be limited to statements relating to: mineral resource estimates; the future price of copper; the potential recoverability of gold at the Karchiga Project; anticipated costs relating to mining, processing and operating; the expected completion of the DFS and the timing related thereto; the anticipated completion of a mineral reserves estimate for the Karchiga Project; the potential for an increase in the life of mine and a reduction in the stripping ratios at the Karchiga Project.

Factors that could cause actual results to differ materially from those described in such forward-looking information include, but are not limited to, uncertainties in the interpretation of drill and test results, risks normally incidental to exploration and development of mineral properties, the possibility that future exploration, development and/or mining results will not be consistent with expectations, uncertainty of mineral resources estimates, the Company's inability to obtain, maintain, renew and/or extend required licences, permits, authorizations and/or approvals from the appropriate regulatory authorities and other risks relating to the regulatory framework in Kazakhstan, adverse changes in the political environment in Kazakhstan and the laws governing the Company, its subsidiaries and their respective business activities, uncertainties in the assumptions used, and the methodologies employed in, the SRK 2011 Mineral Resource Estimates and in the Micon 2010 Study, adverse changes in commodities prices, as well as certain other risks set out in the Company's public documents, including its annual information form dated March 22, 2011, filed under the Company's profile on SEDAR at www.sedar.com.

The forward-looking information in this press release reflects the current expectations, assumptions and/or beliefs of the Company based on information currently available to the Company. In connection with the forward-looking information contained in this press release, the Company has made assumptions about: the Company's business, the economy and the mineral exploration industry in general; the parameters used in defining the pit optimization for the Karchiga Project, as detailed above; the Company's ability to raise any required additional financing, as needed; the regulatory framework in Kazakhstan with respect to, among other things, the Company's ability to obtain, maintain, renew and/or extend required permits, licences, authorizations and/or approvals from the appropriate regulatory authorities; the political environment in Kazakhstan; and the Company's ability to continue to obtain qualified staff and equipment in a timely and cost-efficient manner to meet the Company's demand. The Company has also assumed that no unusual geological or technical problems or unexpected developments occur, plant and equipment work as anticipated and no significant events occur outside of the Company's normal course of business. Although the Company believes that the assumptions inherent in the forward-looking information are reasonable, forward-looking information is not a guarantee of future performance and accordingly undue reliance should not be put on such information due to the inherent uncertainty therein.

The mineral resource figures contained and/or referred to in this press release are estimates only and no assurances can be given that the indicated levels of minerals will be produced. Such estimates are expressions of judgment based on knowledge, mining experience, analysis of drilling results and industry practices. Valid estimates made at a given time may significantly change when new information becomes available. While the Company believes that the mineral resource estimates contained and referenced herein are well established, by their nature, mineral resource estimates are imprecise and depend, to a certain extent, upon statistical inferences which may ultimately prove unreliable. If such mineral resource estimates are inaccurate or are reduced in the future, this could have a material adverse impact on the Company. Due to the uncertainty that may be attached to inferred mineral resources, it cannot be assumed that all or any part of an inferred mineral resource will be upgraded to an indicated or measured mineral resource as a result of continued exploration. Inferred mineral resources are estimated on limited information not sufficient to verify geological and grade continuity or to allow technical and economic parameters to be applied. The Micon 2010 Study, and the information contained herein derived therefrom, are preliminary in nature and the Micon 2010 Study includes inferred mineral resources that are considered too speculative geologically to have the economic considerations applied to them that would enable them to be categorized as mineral reserves. There is no certainty that the conclusions of the Micon 2010 Study will be realized. Mineral resources are not mineral reserves and do not have demonstrated economic viability. There is no certainty that mineral resources can be upgraded to mineral reserves through continued exploration.

Any forward-looking information speaks only as of the date on which it is made and, except as may be required by applicable securities laws, the Company disclaims any intent or obligation to update any forward-looking information, whether as a result of new information, future events or results or otherwise.