Pluton Resources Limited (ASX:PLV) Metallurgical Tests Give Positive Results On Irvine Iron Ore

Melbourne, Mar 22, 2011 AEST (ABN Newswire) - Pluton Resources Limited (ASX:PLV) are pleased to announce that initial results from the dry magnetic separation test work program undertaken on drill core samples from the Hardstaff Peninsula on Irvine Island have been successful in meeting the company's objectives.

HIGHLIGHTS

- Dry magnetic separation test work on diamond drill core composite samples from the Wonganin Sandstone and Yampi Member indicate that the iron ore is amenable to upgrading to a +40% iron pre-concentrate at 1 millimetre.

- Mass recoveries range from 50% (at the lowest sample iron feed grade) up to 90% mass recovery.

Metallurgical Test Work Objectives

As part of the current pre-feasibility study, a number of different processing options are being considered. These options include full beneficiation processing on Irvine Island (wet and dry), gravity separation, and production of pre-concentrate using dry methods, with final processing to a high grade concentrate to be undertaken offshore.

Each option is being considered as it offers differing capital and operating cost profiles that may impact project economics in a positive manner.

This announcement details the procedure and test work results for dry magnetic separation methods on both the Wonganin Sandstone and Yampi Member drill core samples taken from the Hardstaff Peninsula.

The objective of this particular test was to confirm that a +40% iron pre-concentrate could be produced from both the Wonganin Sandstone and the Yampi Member at a grind size of 1 millimetre. A preconcentrate of +40% iron meets the requirement for shipping to offshore beneficiation facilities.

Beneficiation to a final high grade concentrate utilising spare capacity in Asia would have a significant impact on both capital and operating costs. The following results have met this objective.

Results from the gravity separation test work are pending.

Results

Three diamond drill core composite samples of the Wonganin Sandstone were selected from drill holes ID29, ID33, ID6A and ID6B located at the southern end of the Hardstaff Peninsula. The weighted average % iron head grades for the three composite samples (PLV_MET_1, PLV_MET_2 and PLV_MET_3) prior to test work being conducted were 24.0% Fe, 28.8% Fe and 32.9% Fe respectively.

An additional three diamond drill core composite samples of the Yampi Member were selected from drill holes ID29, ID33, ID33B, ID6A and ID6B located at the southern end of the Hardstaff Peninsula. The weighted average % iron head grades for the three composite samples (PLV_MET_4, PLV_MET_5 and PLV_MET_6) prior to test work being conducted were 32.9% Fe, 31.0% Fe and 52.3% Fe respectively.

Each sample was crushed and screened to 1 millimetre. The material was then fed dry to a bench scale laboratory dry magnetic separator (MECAL). The material is passed through the magnetic separator at a range of increasing magnetic strength to attract the magnetic material.

The bench scale tests indicate that the optimal iron recovery of the Wonganin Sandstone samples (PLV_MET_1 to PLV_MET_3) occurred at a medium magnetic intensity (4000 gauss). The Yampi Member samples achieved optimal iron recovery at a low magnetic intensity (1000 gauss). The iron grade versus head iron from 1000 gauss to 4000 gauss is plotted in the following graph (see link at the bottom of the release).

The bench scale test work indicates that samples are amenable to upgrading to a +40% pre-concentrate by dry magnetic separation provided the minimum average feed grade is 28% Fe. The mass recoveries of these tests range between 50% for the lower iron feed grade to 90% for the highest iron feed grade.

One sample included in the test work was above the 40% feed and produced a pre-concentrate nearing 60% iron.

Comments

Managing Director Tony Schoer said: "The results of the dry magnetic separation test work on the Wonganin Sandstone and Yampi Member are significant in that it demonstrates we can potentially produce a pre-concentrate with grades above +40% iron at a 1millimetre grind size. These results will allow us the opportunity to further examine the application of dry magnetic separation techniques in the current pre-feasibility study.

Producing a pre-concentrate by dry methods offers significant benefits to the Irvine Project as it would eliminate the need for wet tailings storage on the Island and offer the opportunity of producing a final high grade concentrate product in the order of 69% iron with low impurity levels, including silica (refer ASX announcements February 22nd and February 25th 2010), utilising spare capacity in Asian beneficiation plants. Ultimately, this would reduce overall capital and processing costs of the Project.

The pre-feasibility results will determine the optimum processing method to create the best return for stakeholders while meeting our corporate social responsibilities"

For the complete Pluton announcement including graphs, please refer to the following link:
http://www.abnnewswire.net/media/en/docs/352247.pdf

Contact

Mr. Tony Schoer Managing Director and Chief Executive Officer Mob: +61-0411-232-711 Email: tschoer@plutonresources.com