BLACK ROCK MINING LIMITED — Capital/Financing Update 2012

Apr 30, 2012

ASX Announcement

Company Announcements Office Australian Securities Exchange

By e-lodgement

1 May 2012

(ASX Code GRK)

Green Rock acquires 20% interest in Backreef Area in Canning Basin

Highlights

• Option exercised and payment made to acquire 20% interest in the Backreef Area in the Canning Basin for $2.5 million

• Cased Hole Production Test scheduled for mid- May 2012

• Re-entry into existing well with indications of oil on the logs

• Payment funds further work which may include an exploration well to be drilled Q3 of 2012

• Backreef Area is directly adjacent to the producing Blina Oilfield, currently owned and operated by Buru Energy Limited

• This acquisition builds on the Company’s existing hydrocarbon interests in the Canning Basin

Green Rock Energy Limited (ASX:GRK) (“Green Rock” or “the Company”) is pleased to advise that it has executed a Share Sale Agreement with Oil Basins Limited (ASX:OBL) (“Oil Basins”) to acquire a subsidiary company of OBL which holds beneficial rights to a 20% joint venture interest in the highly prospective Backreef Area in the Canning Basin. This acquisition has enabled Green Rock to increase its footprint in the Canning Basin and gain exposure to a near term production test for oil in the Backreef-1 well. Other commercial oil discoveries in the area include the

producing Blina Oilfield and the Ungani Well, both operated by Buru Energy Limited. A map of the area and the Backreef-1 well location is below.

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Location of Backreef Area in Canning Basin (courtesy of Oil Basins Limited) Note: Derby block not included in this transaction.

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Location of Backreef-1 within yellow shaded Backreef Area (courtesy of Oil Basins Limited

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----- Start of picture text ----- Backreef-1 Oil Pool----- End of picture text -----

OBL announced on 26 April 2012 (as Operator of the Backreef Area) that it expects the Backreef-1 Production Test to commence in mid May.

The acquisition of beneficial rights to a 20% joint venture interest in the Backreef Area increases Green Rock’s interest in the Canning Basin. Specifically it adds the potential for significant increase in value for the Company and Shareholders if the production test demonstrates a discovery by de-risking the leads and prospects in the area, and through the potential production of the Backreef-1 Well.

In 2011 Green Rock farmed into EP417 in the Canning Basin with New Standard Energy Limited (NSE), earning a 15% interest in the licence area with a right to earn up to 20%. In addition to the farm-in Green Rock and NSE executed an Area of Mutual Interest (40% and 60% respectively), whereby the parties actively pursue new exploration opportunities for unconventional hydrocarbons. This includes the Seven Lakes Special Prospecting Authority adjacent to EP417 awarded to NSE. The Seven Lakes work program is expected to be completed during 2012.

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Nigel Hodder Company Secretary

Investors and Media T: +61 (0) 9482 0482 E: info@greenrock.com.au

About Green Rock Energy Limited

Listed on the ASX in 2005, Green Rock (GRK) is a geothermal and hydrocarbons explorer and developer with geothermal interests in Western Australia, South Australia and Hungary and hydrocarbons interests in Western Australia. Its key projects are:

• A 15% interest in EP417 in the Canning Basin with a right to earn up to 20% through a farm-in agreement with

• Attachments New Standard Energy (NSE) together with an Area of Mutual Interest Agreement for other potential

• opportunities including the Seven Lakes Special Prospecting Area awarded to NSE

• • 1.The beneficial right to a 20% JV interest in the Backreef Area in the Canning Basin operated by Oil Basins Summary of the Terms of the Heads of Agreement Limited (OBL)

• • 2.An alliance with leading Australian renewable power developer Pacific Hydro for conventional geothermal power About Oil Basins Limited generation in GRK’s permits in the Mid West of WA and GRK’s and Pacific Hydro’s licences in the Great Artesian Basin in SA

• A joint venture with MOL in Hungary for geothermal power generation (GRK 50%)

ABOUT OIL BASINS LIMITED (OBL)

OBL is involved in exploration and development of oil and gas in the offshore Gippsland Basin, Victoria, the onshore Canning Basin of Western Australia and the offshore Carnarvon Basin, Western Australia.

Presently, the Company’s portfolio includes:

• 12.5% Rights to Vic/P41 situated in offshore Gippsland Basin,

• 17% interest in Vic/P66 situated in offshore Gippsland Basin,

• 100% Beneficial Rights and operator Backreef Area, onshore Canning Basin

• 50% interest in EP5/07-8 situated in onshore Canning Basin (designated operator CSG and USG).

• 100% interest and operator R3 situated in offshore Carnarvon Basin

OBL regularly performs inhouse and external geological and geotechnical assessments of oil and gas sector farmin, investment and acquisition opportunities and remains interested in expanding its portfolio in both upstream and downstream opportunities within Australia and internationally.