AVM.L Regulatory News (AVM)

5 October 2011

AVOCET MINING PLC

INATA MINERAL RESERVE INCREASED BY 40% TO 1.46 MILLION OUNCES

Avocet Mining PLC ("Avocet" or "the Company") announces a new Proven and Probable Ore Reserve ("Mineral Reserve") estimate at the Inata mine of 23.6 Mt at a grade of 1.93 g/t Au for 1,462,500 ounces of gold as at 30 June 2011. This extends the mine life to approximately 2020 at the current life of mine average annual production of 2.7 Mt of ore processed.

The new Mineral Reserve represents an increase of 417,200 ounces or 40 per cent since the last reported Mineral Reserve as at 31 December 2010 of 15.4 Mt at a grade of 2.11 g/t Au for 1,045,300 ounces, before taking into account depletion due to mining.

After allowing for depletion of 92,000 ounces between 31 December 2010 and 30 June 2011, the new Mineral Reserve represents a gross increase of 509,200 ounces or 49 per cent.

The table below reports the Mineral Reserve beneath the 30 June 2011 topographic surface and above a 0.7 g/t Au economic cut off grade. It reflects an open pit optimisation study based on revised cash costs of US$1.51/t for mining and US$22.74/t for administration and processing; and compared to previous cash costs of US$1.20/t for mining and US$22.15/t for administration and processing. The table below also uses a gold spot price of US$1,200 per ounce of gold, and compares with US$1,000 per ounce used for the previous Mineral Reserve and current gold price of approximately US$1,650.

1) The government of Burkina Faso owns 10% of Société des Mines de Bélahouro SA which owns and operates the Inata Gold Mine

2) Mineral Reserves are reported in compliance with Canadian National Instrument 43-101

The new Mineral Reserve is the result of a thorough economic analysis and revised pit design that is based on the recently announced Mineral Resource for the Inata mine license area of 3.36 million ounces, including 2.54 million ounces of Measured and Indicated Resources. This analysis and design has facilitated extensions to all of the pits at Inata. The Inata North pit in particular has increased in depth and now represents approximately 50 per cent of Inata's total Mineral Reserve. The other five pits, where mineralisation is closer to surface, have extended along strike and/or depth. The Minfo Trend in particular includes zones of Inferred Mineral Resources, which cannot yet be used for open pit designs or inclusion as Mineral Reserves.

As previously relayed, a further update on the Mineral Reserve is expected in Q1 2012 following completion of outstanding drilling in the fourth quarter of 2011 and the inclusion of approximately 16,000 assays from the 2010-2011 drilling programme that had not been received at the time of the latest Mineral Resource update.

The increase announced today supports management's objective of further increasing the production at the Inata Mine from 165,000 ounces per annum to a preliminary target of 245,000 ounces per annum through the construction of additional processing capacity.

Commenting on the Mineral Reserve upgrade at Inata, Brett Richards, Chief Executive Officer for Avocet, stated:

"The anticipated ongoing growth in Mineral Resources and Mineral Reserves at Inata demonstrates the high quality of this asset and provides Avocet with a solid cornerstone for our expansion plans both within the Inata mining license area, as well as in the greater Bélahouro region."

The parts of this press release pertaining to the Mineral Reserve estimate were reviewed by R. Dennis Bergen, P. Eng., Associate Principal Mining Engineer, Roscoe Postle Associates Inc, a qualified person as defined by National Instrument 43-101.

Notes to Editors

Avocet Mining PLC ("Avocet" or "the Company") is a gold mining and exploration company listed on the AIM market of 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 Burkina Faso (as 90 per cent owner of the Inata gold mine and 100 per cent owner of 8 exploration licences in the Bélahouro region surrounding Inata) and exploration in Guinea.

In December 2010 Avocet announced that it had signed a binding agreement for the conditional sale of its South East Asian assets to J & Partners L.P., a private company, for US$200 million. To date US$197 million of the total consideration has been received.

The substantial completion of this transaction has left Avocet as a West African gold producer and explorer, with a clear strategy for growth in that region.

The Inata deposit presently comprises a Mineral Resource of 3.36 million ounces and a Mineral Reserve of 1.46 million ounces. Inata poured its first gold in December 2009 and has now reached a production rate in excess of 13,500 ounces per month. Other assets in West Africa include exploration permits in Burkina Faso (the most advanced prospect within Bélahouro being the Souma trend, some 20 kilometres from Inata, with a Mineral Resource of 561,100 ounces), Guinea (the most advanced being the Tri-K gold exploration project with a Mineral Resource of 1.10 million ounces) and Mali.