Group Mineral Resource Increases 23% to 7.70M oz.

Group Mineral Resource Increases 23% to 7.70M oz.

Avocet Mining PLC ("Avocet" or "the Company"), a leading West African gold mining and exploration company, today announces that its total Mineral Resources have increased to 7.704 million ounces across its operations. This represents an increase of 1.440 million ounces or 23% over its previously stated total Mineral Resource of 6.260 million ounces as at December 2011. The revised Mineral Resource estimates reflect completion of modelling of the drill results from the 2011/2012 field seasons at the Company's exploration projects in Burkina Faso and Guinea.

Burkina Faso

Avocet owns 90% of the Inata Gold Mine in north-east Burkina Faso, with the Government of Burkina Faso owning the remaining 10%, as well as 100% of the eight surrounding exploration licences. Over the 2011/2012 field season 246 drill holes for 28,503 metres were drilled and the results were included in the revised Mineral Resource estimate.

The Mineral Resource within the Inata mining licence area is now estimated at 3.985 million ounces, which represents an increase of 530,000 ounces, or 15%, over the previous estimate. With the addition of Filio, which is located on an exploration licence adjacent to the mine licence area, the Mineral Resource in the immediate vicinity of Inata has grown to 4.126 million ounces, which is an addition of 671,000 ounces or 20%. This overall increase represents a 26% increase in total tonnes and a 5% decrease in grade to 1.37 g/t Au.

The increase in Mineral Resources is largely attributable to the expansion of the Minfo trend to the east where the Minfo East deposit extends to include a maiden resource at Filio, as well as the identification of additional ore intersections almost parallel to the main orebody at Inata South. There are also a number of parallel zones to the north of the Minfo trend. These zones all add oxide material to the Mineral Resource.

Drilling has been ongoing at Filio since early 2011. The deposit lies 5.5km south-east of the existing processing plant and it is expected that it could be processed by the current Inata facility.

The table below reports the Mineral Resource estimate for Inata and Filio beneath the 30 September 2012 topographic surface and above a 0.5 g/t Au cut-off grade. This estimate has been made and reported in accordance with the Australasian code for the reporting of Exploration Results, Mineral Resources and Ore Reserves (JORC Code). The Mineral Resource has also been estimated and in accordance with the principles of the Canadian NI 43-101.

The Company owns 90% of Société des Mines de Bélahouro, owner of the Inata Gold Mine and 100% of the eight exploration licences within the Bélahouro region.

Note: rounding errors may occur.

In addition to the Mineral Resource of 3.985 million ounces of Mineral Resource at Inata and 0.141 million ounces at Filio, an Inferred Mineral Resource of 0.561 million ounces exists at Souma where Avocet holds an exploration licence. Accordingly Avocet's total Mineral Resource in Burkina Faso is now 4.687 million ounces.

The Company is re-estimating its Mineral Reserves at Inata using current cost levels and lower forecast metallurgical recoveries. These factors are likely to negatively influence the estimate, with the result that Mineral Reserves are expected to decrease from the 1.85 million ounces previously announced.

Guinea

Avocet owns 100% of a block of exploration licences in the north-east of Guinea, collectively referred to as Tri-K. Tri-K consists of three main areas namely Koulékoun, Kodiéranand Kodiafaran. The Ministry of Mines and Geology in Guinea has recently extended the Koulékoun licence until October 2013 by which time Avocet intends to have completed its Feasibility Study on the development of a mine at Koulékoun and Kodiéran.

Exploration drilling was undertaken at Koulékoun and Kodiéran from December 2011 until June 2012 and the Mineral Resource estimate is updated as follows:

This estimate has been made and reported in accordance with the JORC Code. The Mineral Resource has also been estimated and in accordance with the principles of the Canadian NI 43-101.

Overall the Tri-K resource has grown by 773,000 ounces or 34% to 3.017 million ounces. Of this increase 319,000 ounces were at Koulékoun, where the Mineral Resource has grown by 17%. The Mineral Resource has also been upgraded by infill drilling across the northeast trending structure that bisects the deposit. Of the total Mineral Resource at Koulékoun, 65% is now in the Indicated category. In total 271 holes for 23,380 metres were drilled at Koulékoun in the 2011/ 2012 field season that contributed to this revised estimate. The average grade for the Koulékoun deposit is 1.27g/t Au which is in line with the previous estimated grade of 1.29 g/t Au. The cut-off for this Mineral Resource estimation has remained at 0.5 g/t Au. Weathering of the ore body at Koulékoun extends to a depth of approximately 80 metres. There is a very narrow transition zone and the remainder of the ore body is fresh rock.

In Kodiéran, the Mineral Resource has increased 110% to 865,000 ounces with deposit growth both along the strike of the ore body and at depth. In total 264 holes for 25,470 metres were drilled at Kodiéran in the 2011/2012 field season that contributed to this revised estimate. Drilling results indicate that weathering of the deposit at Kodiéran extends down to between 100 and 150 metre depths and that accordingly 57% of the Mineral Resource is oxide or transition.

Drilling at Kodiéran is at 50 metre intervals. According to best practice, the Mineral Resource is therefore categorised as Inferred, although the geological continuity along strike is very good. Infill drilling will commence as part of the Feasibility Study scheduled to start shortly. The average grade at Kodiéran has declined from 1.76g/t Au to 1.45g/t Au as volumes of lower grade ore on the periphery of the ore body have been included in the Mineral Resource model. The cut off for this Mineral Resource estimation has remained at 0.5g/t Au.

The information in this announcement pertaining to the Mineral Resource is based on information compiled by Mr. John Milovanovic (FAusIMM), Chief Resource Geologist for Avocet and Mr. David Williams (MAusIMM, MAIG), Principal Consultant, CSA Global Pty Ltd. Mr. Milovanovic and Mr. Williams have experience relevant to the style of mineralisation and type of deposit under consideration and qualify as Competent Persons as defined by the JORC Code , and Mr. Milovanovic and Mr. Williams as Qualified Persons as defined by the Canadian National Instrument 43-101 (NI43-101), for the reporting of Exploration Results, Mineral Resources and Mineral Reserves. Mr. Williams and Mr. Milovanovic consent to the inclusion of the technical information in this announcement in the form and context in which it appears.

FOR FURTHER INFORMATION PLEASE CONTACT

NOTES TO EDITORS

Avocet Mining is a gold mining and exploration company listed on the London Stock Exchange (Ticker: AVM.L) and the Oslo Børs (Ticker: AVM.OL). The Company's principal activities are gold mining and exploration in West Africa.

In Burkina Faso the Company owns 90% of the Inata Gold Mine. The deposit at Inata currently comprises a Mineral Resource of 3.985 million ounces and a Mineral Reserve of 1.85 million ounces. The Inata Gold Mine poured its first gold in December 2009 and produced 167,000 ounces of gold in 2011 and is expected to produce 135,000 - 140,000 ounces of gold in 2012.

Other assets in Burkina Faso include eight exploration permits surrounding the Inata Gold Mine in the broader Bélahouro region. The most advanced of these projects are Souma, some 20 kilometres from the Inata Gold Mine, and Filio, adjacent to the mine licence area, where Mineral Resources of 0.56 million ounces and 0.141 million ounces respectively exist.

In Guinea, Avocet owns twelve exploration licences in the north east of the country. Mineral Resource development has been ongoing since 2005 and the project at Tri-K is the most advanced. Within the Tri-K project, Koulékoun has a Mineral Resource of 2.152 million ounces and Kodiéran of 0.865 million ounces.