Riverstone Resources Inc.
TSX VENTURE : RVS
FRANKFURT : 3RV

Riverstone Resources Inc.

May 11, 2009 11:50 ET

Riverstone Announces NI 43-101 Resource Estimate of 1.14 Million Ounces Gold at Karma

VANCOUVER, BRITISH COLUMBIA--(Marketwire - May 11, 2009) - Riverstone Resources Inc. (TSX VENTURE:RVS)(FRANKFURT:3RV) is pleased to announce the results of an independent, NI 43-101 compliant resource estimation for the Karma Project in Burkina Faso, West Africa. The resource estimate was calculated by Wardrop Engineering and a full report will be filed with SEDAR within 45 days.

HIGHLIGHTS

- Initial NI 43-101 compliant gold resource estimate on the Karma Project of 820,500 ounces in the indicated category and 320,300 ounces in the inferred category.

- Mineralization remains open at depth and along strike at all four of the deposits that comprise the Karma Project.

- Four gold deposits discovered to date, with numerous gold occurrences and artisanal workings not yet drill tested.

- The resource is shallow with 95% above 100 metres in depth.

- Less than CDN $10 per ounce discovery costs for new ounces.

- A follow-up reverse circulation ("RC") drilling program is planned to expand the resources in all four deposits.



TABLE 1 - SUMMARY OF KARMA RESOURCE(1)

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Tonnage Grade Contained Gold
Category (million tonnes) (g/t Au) (ounces)
-------------------------------------------------------------------------
INDICATED 21.4 1.20 820,500
INFERRED 12.2 0.82 320,300
-------------------------------------------------------------------------
(1) Resources are reported at a cut-off of 0.3 g/t for oxide and 0.5 g/t
for fresh rock Ounces are calculated assuming 100% recoveries.


Michael D. McInnis, President of Riverstone, commented, "We are extremely pleased with the results of our first resource estimate for the Karma project. We believe that there is excellent potential to significantly expand the resource and establish Karma as one of the premier gold projects in West Africa."

The Karma Project consists of four separate deposits - Kao, Rambo, GG1 and GG2. GG1 and GG2 are 8 kilometres west of Rambo, and Kao is 7 kilometres south of Rambo, allowing the company to envision the establishment of a central processing facility (to view Figure 1 please click on the following link: http://media3.marketwire.com/docs/RVS0511a.pdf). In addition, there are numerous other gold occurrences and artisanal workings in the immediate vicinity of each of the deposits which require evaluation. The Kao deposit, in particular, has demonstrable potential to significantly increase in size based on RAB drilling results and adjacent gold-in-soil geochemical anomalies (to view Figure 2 please click on the following link: http://media3.marketwire.com/docs/RVS0511b.pdf).

GG2 Deposit

The Goulagou 2 (GG2) deposit is an east-west trending, steeply-dipping lens or series of lenses which has been traced over a strike length of 2.1 kilometres and is up to 140 metres wide. The deposit thickens in the middle where the oxidation extends up to 100 metres in depth. It is hosted by a mixed sequence of sediments containing fine quartz stringers between two large intrusive masses. It has been drilled by 169 diamond and 86 RC drill holes, and the deposit remains open along strike and at depth. The deposit along with GG1 was discovered by Channel Resources and Placer Dome in the late 1990's and then expanded by St Jude Resources before its takeover by Golden Star Resources. An independent resource estimate report on GG1 and GG2 dated January 16, 2007 was previously prepared on behalf of Golden Star by SRK Consulting (UK) Ltd. and is available on SEDAR. Riverstone's work was successful in converting most of the inferred ounces in the SRK estimate to the indicated category.



TABLE 2 - SUMMARY OF GG2 RESOURCE(1)

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Tonnage Grade Contained Gold
Category (million tonnes) (g/t Au) (ounces)
-------------------------------------------------------------------------
INDICATED 6.7 1.83 390,500
INFERRED 1.4 1.10 48,600
-------------------------------------------------------------------------
(1) Resources are reported at a cut-off of 0.3 g/t for oxide and 0.5 g/t
for fresh rock Ounces are calculated assuming 100% recoveries.


GG1 Deposit

The Goulagou 1 (GG1) deposit lies approximately 2 kilometres northwest of Goulagou 1. It is northeast trending and has similar geology. Like Goulagou 2, it comprises a series of lenses, traceable over 1.1 kilometres with a width up to 175 metres. It has been tested by 52 diamond and 15 RC drill holes, mainly in the oxide zone, and it remains virtually untested at depth.



TABLE 3 - SUMMARY OF GG1 RESOURCE(1)

-------------------------------------------------------------------------
Tonnage Grade Contained Gold
Category (million tonnes) (g/t Au) (ounces)
-------------------------------------------------------------------------
INFERRED 6.9 0.63 140,400
-------------------------------------------------------------------------
(1) Resources are reported at a cut-off of 0.3 g/t for oxide and 0.5 g/t
for fresh rock Ounces are calculated assuming 100% recoveries.


Resources at Goulagou were estimated by inverse distance weighted to the second power using Gems software version 6.2. Resources were classified as indicated if at least three holes were found within a 75m search radius. All other blocks within the modeled wireframe were classified as inferred.

Kao Deposit

The Kao deposit is a near-surface, gently-dipping tabular zone that has been defined over an area of approximately 800m by 400m. The deposit remains open in most directions, particularly to the north and below a depth of 85 metres. Shallow RAB drilling on the northern edge of the deposit indicates that the deposit may continue in this direction for at least another 750 metres, but at a slightly greater depth. The Kao deposit is hosted entirely in intrusive rock and it lies near the southern end of a six kilometre long soil anomaly. This same intrusive is exposed throughout the soil anomaly where gold values have been confirmed in numerous locations by rock chip sampling and RAB drilling. RAB drilling approximately 3 kilometres northeast of the Kao deposit intersected 1.54 g/t gold over 12m, with RAB holes 1 kilometre further northeast grading 1.68 g/t gold over 3m, 1.86 g/t gold over 12m and 6.73 g/t gold over 3m. The chances of expanding the Kao deposit and of finding other gold deposits within this six-kilometre long soil anomaly are considered to be very high.



TABLE 4 - SUMMARY OF KAO RESOURCE(1)

-------------------------------------------------------------------------
Tonnage Grade Contained Gold
Category (million tonnes) (g/t Au) (ounces)
-------------------------------------------------------------------------
INDICATED 14.7 0.91 430,000
INFERRED 3.7 0.65 76,400
-------------------------------------------------------------------------
(1) Resources are reported at a cut-off of 0.3 g/t for oxide and 0.5 g/t
for fresh rock Ounces are calculated assuming 100% recoveries.


Resources at Kao were estimated by ordinary kriging using Gems software version 6.2. Resources were classified as indicated if at least three holes were found within a 70m search radius. All other blocks within the modeled wireframe were classified as inferred.

Rambo Deposit

The Rambo deposit is a steeply dipping gold zone that has been traced for 300 metres along strike and to a depth of 100 metres. It is hosted in mixed sediments and volcanics along the southern margin of a major intrusive. The deposit remains open at depth and along strike. The possibility of discovering separate gold zones is highlighted by vertical RAB holes grading 1.9 g/t gold over 36 metres (including 2.59 g/t gold over 21m) located 750 metres northwest of the Rambo pit, and 1.24 g/t gold over 9 metres located 400 metres northeast of Rambo.



TABLE 5 - SUMMARY OF RAMBO RESOURCE(1)

-------------------------------------------------------------------------
Tonnage Grade Contained Gold
Category (million tonnes) (g/t Au) (ounces)
-------------------------------------------------------------------------
INFERRED 0.3 7.02 56,900
-------------------------------------------------------------------------
(1) Resources are reported at a cut-off of 2 g/t. Ounces are calculated
assuming 100% recoveries.


Resources at Rambo were estimated by inverse distance weighted to the second power using Gems software version 6.2. All blocks within the modeled wireframe were classified as inferred.

The Kao, Rambo, GG1 and GG2 resource estimate was prepared under the supervision of Dr. Gilles Arseneau, P. Geo. of Wardrop Engineering, who is a qualified person as defined under National Instrument 43-101, using computer-generated wireframe models, based on 52 diamond (4,755m) and 15 RC (1,367m) drill holes at GG1, 169 diamond (17,951m) and 86 RC (7,086m) drill holes at GG2, 173 RC (17,741m) drill holes at Kao, and 14 diamond (2,477m) and 17 RC (2,268m) holes at Rambo.

The RC drill programs and sampling conducted by Riverstone were supervised by Paul G. Anderson, P. Geo., a qualified person and Exploration Manager for the Company. The Company maintains a rigorous quality control program involving the use of repeat assays, check assays at independent labs, inserted blanks, and the use of verifiable standards from an accredited Canadian laboratory. All RC samples were assayed using standard fire assay with atomic absorption techniques, with samples grading in excess of 2.00 g/t gold re-assayed with a gravimetric finish, at the independent Abilab Burkina SARL laboratories in Ouagadougou, Burkina Faso, which is part of the ALS Chemex group. All assay results were reviewed by Dr. Giles Peatfield, P.Eng., an independent consulting engineer, in order to verify that quality control protocols were honoured.

Riverstone Resources Inc. is active in gold exploration in Burkina Faso, West Africa, where the Company holds an extensive portfolio of high-quality exploration permits covering 2,610 square kilometres. For further information about the Company and its activities, please refer to the Company's website at www.riverstoneresources.com and under the Company's profile at www.sedar.com.

ON BEHALF OF THE BOARD

Michael D. McInnis, P.Eng., President & CEO

Dr. Giles Peatfield, P.Eng., is an Independent Qualified Person for Riverstone Resources and has reviewed and approved the contents of this release.

Certain statements made and information contained in this news release and elsewhere constitutes "forward-looking information" within the meaning of the Ontario Securities Act. Forward-looking statements are subject to a variety of risks and uncertainties which could cause actual events or results to differ from those reflected in the forward-looking statements, including, without limitation, risks and uncertainties relating to the interpretation of drill results and the estimation of mineral resources, the geology, grade and continuity of mineral deposits, the possibility that future exploration, development results will not be consistent with the Company's expectations, accidents, equipment breakdowns, title matters and surface access, labour disputes, the potential for delays in exploration activities, the potential for unexpected costs and expenses, commodity price fluctuations, currency fluctuations, failure to obtain adequate financing on a timely basis and other risks and uncertainties, including those described under Risk Factors in each management discussion and analysis. In addition, forward-looking information is based on various assumptions including, without limitation, the expectations and beliefs of management, the assumed long term price of gold, that the Company will receive required permits and access to surface rights, that the Company can access financing, appropriate equipment and sufficient labour and that the political environment within Burkina Faso will continue to support the development of environmentally safe mining projects. Should one or more of these risks and uncertainties materialize, or should underlying assumptions prove incorrect, actual results may vary materially from those described in forward-looking statements. Accordingly, readers are advised not to place undue reliance on forward-looking statements.

Neither TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.

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