Orsu Metals Corporation

April 28, 2011 07:03 ET

Orsu Metals Corporation Announces Positive Metallurgical Test Work Results for the Karchiga Project



April 28, 2011

Orsu Metals Corporation Announces Positive Metallurgical Test Work Results for the Karchiga Project

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.

LONDON, UNITED KINGDOM--(Marketwire - April 28, 2011) - Orsu Metals Corporation ("Orsu" or the "Company")

(TSX:OSU)(AIM: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:

-- Improvement of copper grade in concentrate without loss of copper

recovery and improved zinc rejection in the ores from the Central and

North East lodes and their composite samples ("Froth Flotation");

-- Development of a copper heap leaching process to potentially treat the

oxide ores and transitional secondary sulphide components of the Central

lode ("Heap Leaching").

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


Test % % Cu Grade % Zn Grade % Cu % Zn

Year Mass in in Recovery Recovery

Concentrate Concentrate


2009 10.11 19.90 3.32 91.05 83.84


2011 8.86 27.90 5.00 95.76 81.54


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


% %

% Cu Zn g/t

Mass Grade Grade Au % % %

of in in in Cu Zn Au

Lode Ore Concentrate Concentrate Concentrate Recovery Recovery Recovery


Central 10.34 24.15 1.28 0.34 96.20 73.97 28.18



East 9.98 21.60 7.20 1.65 91.59 86.93 54.95


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


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."


1. The technical report related to the Scoping Study referred to in this

press release entitled "Preliminary Assessment of The Karchiga Copper

Project, East Kazakhstan Region, Kazakhstan", dated May 25, 2010 and

prepared by L S Carroll, MIMMM CGeol FGS, G Harris, MAusIMM, I L Owen,

CGeol EurGeol FGS, J Steedman, MAusIMM and D O Wells, MIMMM CEng of

Micon International Co. Limited is available under the Company's profile

on SEDAR (www.sedar.com).

2. The indicated mineral resource estimates (March 22, 2010) referred to in

this press release are contained in the technical report entitled

"Updated Report on the Karchiga Property held by Orsu Metals

Corporation, Kazakhstan", dated March 22, 2010 and prepared by I L Owen

and L S Carroll of Wardell Armstrong International Limited, which is

available under the Company's profile on SEDAR (www.sedar.com).


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 Company's expectations with respect to

updating and upgrading current mineral resource estimates and the possible increase in tonnage; the timing for

the completion of an updated NI 43-101 compliant resource estimate; and the timing of the Company's receipt of

results from and timely completion of the ongoing Definitive Feasibility Study.

Factors that could cause actual results to differ materially from those described in such forward-looking

information include, but are not limited to, risks normally incidental to exploration and development of

mineral properties, uncertainties in the interpretation of drill and test results, the possibility that future

exploration, development and/or mining results will not be consistent with expectations (including the

possibility that gold may not be able to be economically recoverable from the North East lode), 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, 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 24, 2010, 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 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 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. Inferred mineral resources are too

speculative geologically to have economic considerations applied to them to enable them to be categorized as

mineral reserves. 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.


Orsu Metals Corporation

Ray Oates

Technical Director

+44 (0) 20 7518 3999



Canaccord Genuity Limited

Ryan Gaffney / Andrew Chubb

+44 (0) 20 7050 6500


Vanguard Shareholder Solutions

+1 604 608 0824

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