BLACK ROCK MINING LIMITED — Capital/Financing Update 2012

May 6, 2012

ASX Announcement

Company Announcements Office Australian Securities Exchange

By e-lodgement

7 May 2012

(ASX Code GRK)

Update on preparation for Backreef-1 Production Test from OBL

Please find attached ASX announcement dated 7 May 2012 from Oil Basins Limited, as operator of the Backreef Area, regarding progress with preparations for the Backreef-1 Production Test.

==> picture [74 x 33] intentionally omitted <==

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:

• Attachments • A 15% interest in EP417 in the Canning Basin with a right to earn up to 20% through a farm-in agreement with 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.An option to acquire from Oil Basins Limited (OBL) up to 20% of the Backreef Area in the Canning Basin Summary of the Terms of the Heads of Agreement

• An alliance with leading Australian renewable power developer Pacific Hydro for conventional geothermal power 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%)

==> picture [532 x 55] intentionally omitted <==

==> picture [220 x 84] intentionally omitted <==

==> picture [224 x 46] intentionally omitted <==

7 May 2012

ASX Markets Announcements Australian Stock Exchange Limited 10[th] Floor, 20 Bond Street Sydney NSW 2000

Dear Sirs

BACKREEF-1 PRODUCTION TEST

Oil Basins Limited (ASX codes OBL , OBLOA and OBLOB or the Company) wishes to make the following announcement so as to keep the market fully informed.

The Company, as operator Backreef Area, wishes to advise that subject to receiving all necessary approvals and consents from the DMP to conduct the forthcoming Backreef-1 Production Tests the anticipate timetable is as follows:

Rig-up of ADS Rig#2* 15 May^ Production testing 17 – 20 May^ Rig-down/demobilisation Circa 21 May^

Notes: * Site works were completed as expected on 4 May 2012. ^ Indicative and subject to change.

OBL will duly advise the market of the following:

• 1) When all approvals have been obtained;

• 2) When the ADS Rig#2 has arrived onsite; and

• 3) Summary of the test results at the conclusion of the Backreef-1 Production Test program.

In addition, with the significant additional costs of conducting two production tests (rather than only one as originally planned in the previous budget of $900,000) and the unforeseen additional costs associated with site works and mobilization of an appropriate camp from Geraldton (rather than Derby area), the likely revised budget is now circa $1.8 million.

Attached to this Update are the objectives of the Backreef-1 Production Test program.

Yours faithfully

==> picture [187 x 57] intentionally omitted <==

Neil Doyle SPE Director & CEO

BACKREEF-1 PRODUCTION TEST

Objectives

• 1) To conduct a production test under strict PRMS SPE guidelines.

• 2) To recover hydrocarbons to the surface either via modern (Sampler Chamber) packer test* or conventional DST.

• 3) Characterise the previously poorly defined reservoir fluid properties.

• 4) Establish steady state downhole reservoir pressure and surface fluid production rates and fluid and hydrocarbon composition.

• 5) Better define the nature of the possible contingent resources and so better define the subsequent Work Program 2012 i.e. EPT / Backreef-2 or East Blina-1

*The sampler allows a downhole reservoir fluid sample to be retrieved. It functions in sequence with the hydraulic shut-in tool. Once the hydraulic shut-in tool is opened, the sampler will be opened and it captures a sample once the shut-in tool is closed.

Backreef-1 – Present Status

• First well drilled within Kimberley Downs Embayment and first well in L6 for circa 25 years

• Safely drilled to 1800mRT in October 2010

• Cost approx $4.55 m

• Over 223m of continuous fluorescence observed 889m -1112m RT

• The zone between 910m - 965mRT being most prospective

• Well suspended at PBTD of 1155mRT

Weatherford’s proprietary Petrolog CPX Petrophysical Assessment of Backreef-1 Logs ( refer to OBL ASX Release dated 29 November 2010) delineated:

• Porosity circa 22% - much higher than Blina Oil Field reservoir equivalent units

• Reservoirs :Yellow Drum equivalent and Gumhole dolomites – porosity circa 22%

• Gross Reservoir interval 48.9m

• Net Oil Pay interval 39.2m; including (Zone 2) 22m (best interval) 918m to 940mRT

• Risked Net Free oil 3.9m pre-stimulation (Zone 1 ) (best interval) 957-961m RT

• SwIrr = 20%

2

Production Test Program

Two separate production tests will be conducted, one after another, across intervals in the Gumhole and Yellow Drum dolomites.

• 1) Production Test 1 – Gumhole Formation (Zone 1) – 4 m interval from 957 m to 961 mRT – assessed on logs by both Weatherford and independently by RPS Energy (RPS) as best productive interval within the delineated dolomites - refer to OBL ASX Releases dated 24 November 2011 and 16 January 2012 .

• 2) Production Test 2 – Yellow Drum Formation (Zone 2) – 22 m interval from 918 m to 940 mRT – assessed on logs by Weatherford as being prospective, albeit within a tight dolomite upper section (Note: RPS did not include or consider Zone 2 in its evaluation).

==> picture [329 x 372] intentionally omitted <==

Figure 1: Backreef-1 Production Test Zones 1 and 2

Potential Impact of Production Tests

• If the lower test in the Gumhole Formation (Zone 1, Figure 1) recovers hydrocarbons, the result will be consistent with the Backreef Oil Pool contingent resource estimate determined by the earlier RPS study.

• If Zone 1 recovers oil, then this column is below the interpreted structural closure and the trap is possibly stratigraphic in nature (Figures 2 and 3) .

3

• If in addition, the upper zone in the Yellow Drum Formation (Zone 2) recovers hydrocarbons then OBL’s interpretation is that this oil column is likely contained by structural closure.

• In the event that both zones fail to recover significant hydrocarbons, the interpretation could be that Backreef-1 drilled the reservoirs just below the field oil/water contact, possibly within the transition zone between the oil column and the underlying water.

• The presence of a transition zone is supported by the observation of live oil shows in the two reservoir zones.

• If no significant hydrocarbons are recovered in the two tests, then OBL will then consider better defining the Backreef structure with additional seismic acquisition.

• Potential for structural closure up-dip of Backreef-1 does occur because the structure at present is defined by a single seismic line (Figures 2 and 3) - refer also to the RPS study.

• Future appraisal of the Backreef structure would then be aimed at penetrating the reservoirs at a structurally higher position than at Backreef-1.

==> picture [452 x 305] intentionally omitted <==

Figure 2: Backreef Structure – Top Yellow Drum Formation Source RPS

4

==> picture [452 x 286] intentionally omitted <==

Figure 3: PSDM Seismic Line BV93-17 across the Backreef Structure Source RPS

DISCLAIMER

The technical information quoted has been complied and / or assessed by Mr Geoff Geary who is a professional geologist (Bachelor Science – Geology) with over 32 years standing and who is also a Member of Petroleum Exploration Society of Australia. Mr Geary has consented to the inclusion of the technical assessment in this ASX announcement. Investors are reminded at all times refer to the appropriate OBL ASX Releases and the information in the form and context in which they originally appear and in particular to the review the risk sections of the RPS expert report.

• GLOSSARY & PETROLEUM UNITS M Thousand MM Million B Billion bbl Barrel of crude oil (ie 159 litres) PJ Peta Joule (1,000 Tera Joules (TJ)) Bcf Billion cubic feet Tcf Trillion cubic feet (ie 1,000 Bcf) BOE6 Barrel of crude oil equivalent – commonly defined as 1 TJ equates to circa 158 BOE – approximately equivalent to 1 barrel of crude equating to 6,000 Bcf dry methane on an energy equivalent basis

• PSTM Pre-stack time migration – reprocessing method used with seismic. PSDM Pre-stack depth migration – reprocessing method used with seismic converting time into depth.

• AVO Amplitude versus Offset, enhancing statistical processing method used with 3D seismic. TWT Two-way time FMT Formation testing (pressure & sampling) tool TD Total depth GIP Gas in Place RT Relative to rotary turntable OWC Oil water contact STOIIP Stock tank oil in place (stabilised crude at atmospheric conditions) – also commonly referred to as Oil in Place (OIP)

• SwIrr Irreducible water saturation

5