April 28, 2011

As part of ongoing Definitive Feasibility Study, Orsu announces positive results of the final metallurgical test work for its Karchiga Project in Eastern Kazakhstan. The test work indicates that the composite ore material from the two lodes should produce a 27.9% Cu concentrate, with 95.76% recovery, and the ores from the North East and Central lodes should produce a 21.6% and 24.15% Cu concentrate, with 91.59% and 96.2% recoveries, respectively.

Orsu Metals Corporation (TSX:OSU), the London-based precious and base metals exploration and development company, is pleased to announce the results of the final metallurgical test work, which was carried out by the Eastern Research Institute for Base Metals ("VNIITsvetMet") based in Ust-Kamenogorsk, Kazakhstan as part of ongoing Definitive Feasibility Study ("DFS"). All test work was conducted under the direction of Orsu personnel and our lead consultant SRK Consulting (UK) Limited, Cardiff, UK ("SRK").

The metallurgical test work was conducted on 1.5 tonnes of metallurgical samples, selected from the drill core of metallurgical holes drilled in late 2010 as part of the DFS in both the Central and North East lodes of the deposit. Test results indicate an amenability to produce marketable copper concentrates (see technical report entitled "Preliminary Assessment of The Karchiga Copper Project, East Kazakhstan Region, Kazakhstan", dated May 25, 2010). The recent testwork is the most representative study to date, which was focussed on:

Froth Flotation
A testwork programme, staged in three phases, was performed on a composite sample of sulphide ores from both the Central and North East lodes, mixed in the proportion of 40% to 60%, respectively (the "Main Composite").

During Phase 1, various grinds, reagents and flow sheets were tested. During Phase 2, combinations of the Phase 1 tests with improved parameters were examined. Phase 3 tests were finally comprised of variability testing of the optimised process on spatial diversity of the lodes plus locked cycle testing on composite samples, individually representing the massive and disseminated ores from the Central and North East lodes (the "Central and North East Composites", respectively).

For the Main Composite, reduced quantities of the flotation collectors (Butyl Xanthate and Aerofloat) and the Na2S (Sodium Sulphide) modifier, coupled with extended flotation times in rougher, scavenging and cleaning sections of the flow sheet, gave the desired improvements in the copper concentrate grade. The result for the locked cycle test performed on the Main Composite is given in the Table 1 in comparison with the result from locked cycle test, performed by VNIITsvetMet in 2009 on a similar composite sample.

Table 1 - Locked cycle tests for Main Composite

Table 1 shows a significantly improved copper recovery into concentrate from 91.05% to 95.76%, achieved during the Phase 3 test work programme. At the same time, the copper grade of the concentrate produced from the Main Composite has increased from 19.9% Cu to 27.9% Cu, whereas the overall mass recovery into the concentrate has been lowered from 10.11% to 8.86%, which will ultimately translate to reduced transportation costs.

The zinc recovery has been lowered from 83.84% to 81.54% while the zinc grade in the concentrate has increased, partly due to the higher zinc head grade, still remaining at an acceptable level of 5% Zn. The greater flotation selectivity, achieved in this round of testwork, affords the opportunity to operate at a lower concentrate grade of, for instance, 25% Cu, which would result in an increase in the copper recovery and a decrease in the zinc grade in the concentrate.

In addition, the gold grade in the Main Composite concentrate was 1.57 g/t Au, with 50.44% recovery.

Table 2 shows results from locked cycle tests performed on the samples, representing the Central and North East Composites of the two individual lodes and respective potential pits of the Karchiga deposit. The Central Composite is a blend of 15% massive and 85% disseminated ores, whereas the North East Composite is a blend of 25% massive and 75% disseminated ores.

Table 2 - Locked cycle test for the Central and North East Composites

The results for the Central Composite are on a par with those of the Main Composite in terms of copper and zinc grades. The gold grade in the Central Composite concentrate is 0.34 g/t Au.

In the North East Composite, however, the copper grade in concentrate is 21.6%, with the gold grade of 1.65 g/t Au. The level of zinc in the concentrate was higher than expected. This is thought to be related to a build up of frother in the locked cycle test, leading to poor selectivity between the copper and zinc sulphides. This might be simple to rectify. For instance, the ore from the Central pit may be processed alone in the Year 1. A blend of ores from the Central and North East pits may then be processed during Years 2 to 6, and this may be followed by just over 4 years of further processing of ore from the North East pit only. Optimization for mine planning and milling will be undertaken as part of the DFS to determine the best way to blend and treat these ores.

Variability testing using the optimised flotation process has been performed on nine different samples from different locations in the deposit or their composite make up. The variability test results did not highlight any major behavioural deviation in metallurgical response from that of the standard composite in terms of recovery and grade.

Heap Leaching
The Central lode of the Karchiga deposit has an indicated resource of the oxide ore in the amount of 0.923Mt (at 0.5% Cu cutoff) grading 1.39% Cu and containing 12,868 t Cu (see technical report entitled "Updated Report on the Karchiga Property held by Orsu Metals Corporation, Kazakhstan" and dated March 22, 2010). Three acid leach columns were loaded with a blend of oxide and transitional secondary sulphide from the Central pit area and subsequently irrigated with a weak acid solution. Of the three columns, one, which contained added bacteria and which was aerated at the base, significantly outperformed the other two columns. This result was not unexpected and serves to demonstrate the efficiency of bacterial leaching for this type of ore. After 100 days, this column had achieved 68% Cu recovery, which corresponds very closely to 100% of the total material that was available in the sample for leaching.

The reported results of the metallurgical test work are part of the ongoing DFS. Completion of DFS is expected in September 2011.

Dr Sergey V Kurzin, Executive Chairman of Orsu commented: "The sulphide ore flotation tests demonstrate a possibility to achieve a significantly higher copper grade in concentrate and copper recoveries into concentrate from the Karchiga ores than indicated in the May 2010 Scoping Study. They show a marked improvement over all previous test work. These positive results will allow progressing further a detailed engineering design of the ongoing Definitive Feasibility Study. In addition, the positive results of the leaching test work of oxide and transitional ores demonstrate an additional potential economic benefit for the Karchiga Project, which is likely to be realized from the cash flow generated during mining and production of copper from the sulphide ores."

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For further information please contact:

Ray Oates, Technical Director, Orsu Metals Corporation
Tel: +44 (0) 20 7518 3999

Ryan Gaffney / Andrew Chubb, Canaccord Genuity Limited
Tel: +44 (0) 20 7050 6500

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