SISSINGUE MINERAL RESOURCE UPGRADE TENGRELA GOLD PROJECT, IVORY COAST NEWS RELEASE 19 JULY 2010 Perseus Mining Limited (ASX/TSX: PRU) is pleased to announce an upgrade to the Sissingue Mineral Resource at the Company s Tengrela Gold Project in Ivory Coast. Highlights include: Mineral Resource at 1g/t Au cut-off: Measured and Indicated: 9.8Mt at 2.5g/t for 782,670 oz (37% higher in grade than 2009) Inferred: 3.4Mt at 1.7g/t for 184,500 oz Mineral Resource at 0.5g/t Au cut-off: Measured and Indicated: 15.2Mt at 1.9g/t for 914,550 oz (43% additional ounces) Inferred: 7.2Mt at 1.2g/t for 274,200 oz The application of high grade cuts (grade capping) to the assays reduced the reported Mineral Resource grade above a 1g/t Au cut-off by 32%. Drilling is continuing on infill, extensional targets and on other prospects at the Tengrela Project. Definitive feasibility study on track for completion late October 2010. Optimisation studies suggest significantly higher grades in early years than previously thought. Perseus Managing Director, Mark Calderwood s Comments It s pleasing to see the significant increase in resource grade resulting from infill drilling and the subsequent increase in contained gold during conversion from Inferred to Measured and Indicated ( M&I ) Mineral Resources. There is a good chance we can significantly increase the reportable grade by infill drilling the very high grade zones to improve confidence levels, which may lead to less gold being topcut from the model. We will also continue to expand the M&I Mineral Resource base by conversion and extensional drilling, as evidenced by results received subsequent to the current data cut-off date of 14 April 2010. Preliminary pit optimisation work confirms the potential for a very robust project, with exceptional grade, low production cost per ounce, and significantly more production in the early years than we had previously anticipated. Subject to final mine scheduling, the Sissingue deposit has the potential to become a 200,000ozpa contributor in our goal to become a 450,000 to 500,000ozpa gold producer by 2013. Perseus will host a conference call to discuss this upgrade, see page 4 for details. Perseus Mining Limited ABN 27 106 808 986 30 Ledgar Road, Balcatta, Western Australia 6021 PO Box 717 Balcatta WA 6914 Telephone: (618) 9240 6344 Facsimile: (618) 9240 2406 Email address: info@perseus.com Website: www.perseusmining.com 1
Resource Estimate Independent consultant Runge Limited ( Runge ) has completed a Mineral Resource upgrade on Perseus s Sissingue deposit as part of the definitive feasibility study ( DFS ) currently in progress. Tables 1 to 3 below contain a breakdown of the Mineral Resource estimate and notes to the estimate are appended to this announcement. The total M&I Mineral Resource estimate as of July 2010, of 15.2Mt at 1.9g/t Au containing 914,550 ounces of gold (0.5g/t Au cut-off), represents a 43% increase in contained ounces of gold from the October 2009 Indicated Mineral Resource estimate. At a 1g/t Au cut-off grade, the July 2010 M&I Mineral Resource represents an increase of 37%, while Inferred Mineral Resource decreased from 5.5Mt at 1.7g/t Au to 3.5Mt at 1.7g/t Au, reflecting conversion of a portion of the Inferred Mineral Resource following infill drilling. The Measured and Indicated Resource in the top 100m total 6.9Mt at 2.7g/t Au containing 600,000oz of gold based on a 1g/t Au cut-off, of which the highest grade portion would be targeted for the initial 2 years production. High Grade Cuts ( top-cuts ) Mineralisation at the Sissingue deposit is highly variable, with an analysis of the statistics indicating that the drill composite data is positively skewed with a high coefficient of variation. The application of a top-cut to high grade intercepts is considered necessary prior to using the data for linear grade interpolation in these types of deposits. During modelling Runge applied high grade cuts ranging from 10g/t Au to 175g/t Au, depending on the sample populations within the 57 mineralised wireframes (objects) used in the modelling. Using a 1g/t cut-off, the uncut M&I Mineral Resource grade estimate is 32% higher than the top-cut M&I Mineral Resource grade estimate. This 32% difference is unusually high and is a direct result of the very high grades that have been intercepted at the Sissingue deposit. Three notable domains containing 1.37Mt of M&I Mineral Resource have an average uncut grade of 10.7g/t Au and a top-cut grade of 4.2g/t Au, representing a 60% reduction in grade from top-cutting. Current infill drilling is expected to clarify the distribution of the very high grade (+100g/t) gold mineralisation which may, ultimately, lead to an upward adjustment in the reportable Mineral Resource grade. Figure 1: Oblique View of Portion of the Sissingue Mineral Resource Coloured by Gold Grade. HG SEDIMENT Au Cut g/t 0.0-0.5 0.5-1.0 1.0-2.0 2.0-5.0 5.0-999 HG DYKE HG GRANITE * HG denotes - high grade 2
Table 1: July 2010 Mineral Resource Estimate Sissingue Deposit at 1.0g/t Au Cut-off Measured Indicated Measured & Indicated Inferred Type Tonnes Au Tonnes Au Tonnes Au Au Tonnes Au Au T g/t T g/t T g/t Ounces T g/t Ounces Oxide 10,300 1.9 2,028,100 2.2 2,038,400 2.2 143,540 599,000 2.1 40,000 Transitional 83,400 3.0 1,134,500 2.8 1,217,800 2.8 111,240 232,000 1.6 11,800 Primary 794,200 3.2 5,755,200 2.4 6,549,400 2.5 527,890 2,646,000 1.6 132,700 Total 887,800 3.2 8,917,800 2.4 9,805,600 2.5 782,670 3,477,000 1.7 184,500 Table 2: July 2010 Mineral Resource Estimate Sissingue Deposit above 0.5g/t and below 1.0g/t Au Measured Indicated Measured & Indicated Inferred Type Tonnes Au Tonnes Au Tonnes Au Au Tonnes Au Au T g/t T g/t T g/t Ounces T g/t Ounces Oxide 0 0.0 1,701,800 0.8 1,701,800 0.8 41,260 612,000 0.7 14,700 Transitional 700 0.8 705,900 0.8 706,500 0.8 17,540 495,000 0.7 11,500 Primary 43,000 0.8 2,966,800 0.8 3,009,800 0.8 73,080 2,665,000 0.7 63,500 Total 43,600 0.8 5,374,500 0.8 5,418,200 0.8 131,880 3,771,000 0.7 89,700 Table 3: Mineral Resource Estimate Sissingue Deposit totals at 0.5 g/t Au Cut-off Measured Indicated Measured & Indicated Inferred Type Tonnes Au Tonnes Au Tonnes Au Au Tonnes Au Au T g/t T g/t T g/t Ounces T g/t Ounces Total 931,400 3.1 14,292,300 1.8 15,223,800 1.9 914,550 7,248,000 1.2 274,200 Note: rounding applied Ongoing Drilling Drilling is continuing at the Sissingue deposit to facilitate further conversion of the Inferred Mineral Resource and to test below and along strike of the US$950 pit optimization shell, which essentially bottomed out on Indicated Mineral Resource. Recent drill intercepts not included in the July 2010 Mineral Resource estimate include: SD098, which intercepted mineralisation about 30m below the current optimization shell; SLC306, which is a new discovery outside the existing model; and SLC316, which is outside the optimized shell, in an area of the current Inferred Mineral Resource estimate. Exploration drilling is also continuing on other prospects at the Tengrela Gold Project. Table 4: Significant Recent Drill Intercepts Sissingue Deposit, Tengrela Gold Project Hole East North Depth Azm. Incl. From To Width Au (m) (m) (m) ( ) ( ) (m) (m) (m) g/t SD098 806886 1154120 209.7 278-55 121 125 4 28.9 incl. 122 123 1 112.1 191 197.8 6.8 3.9 incl. 195.7 196.7 1 17.4 SLC306 807010 1154000 100 270-55 84 96 12 21.2 incl. 86 90 4 58.5 SLC316 806165 1154360 115 270-50 94 114 20 4.3 incl. 98 102 4 15.8 3
Notes 1) SLC holes are reverse circulation drill holes; SD098 is a core drill hole 2) The type of analytical or testing procedures utilized and sample size and the quality assurance program and quality control measures are consistent with those described in the technical report entitled Technical Report Tengrela Gold Project, Ivory Coast dated November 30, 2009. 3) Drill samples were assayed by 50g fire assays by Intertek Minerals Limited, an independent laboratory in Ghana. 4) Recent significant drill intercepts on the Sissingue deposit typically have true widths of 60 to 90% of drill length. Locally, drill intercept length may equate to actual true width, depending upon the variable dip of the mineralisation. Mineralisation is structurally complex, such that true thickness may occasionally be better measured as a range. Most recent drilling at Sissingue has been oriented to the west and mineralisation generally dips to the east, so true thickness is usually significantly greater than 60% of drill length. Definitive Feasibility Study The definitive feasibility study at Sissingue is progressing well and is on track for completion in October 2010. Process plant and infrastructure design is well advanced and is now awaiting pricing confirmation. The environmental baseline is being compiled and the mining study has commenced. First pass pit optimisation studies contemplate significantly higher gold grades in the early years compared to the 2009 scoping study, auguring well for the project economics. Mark Calderwood Managing Director To discuss any aspect of this announcement, please contact: Mark Calderwood at telephone +61 8 9240 6344 or email calderwoodm@perseusmining.com Brian Thornton at telephone +61 2 9332 4448, +61 411366668 or email bt@farrington.com.au (media) Nathan Ryan at telephone +0420 582 887 or email nathan.ryan@nwrcommunications.com.au Rebecca Greco at telephone +1 416 822 6483 or email fighouse@yahoo.com (Toronto) Perseus will host a conference call to discuss the results, as well as to provide an update on operations. Conference Call: Date: Time: Dial-in Numbers Wednesday, July 21 2010 8.30am Canadian Eastern Time (Toronto 8.30am) (Sydney 10.30pm) (Perth 8.30pm) To be Advised The conference call will feature Mark Calderwood, Managing Director and Chief Executive Officer and West African Exploration Manager, Kevin Thomson. A live audio webcast of the conference can be accessed through Perseus s website at www.perseusmining.com. The audio will be available for replay for a period of 60 days. 4
About Perseus Mining Limited Perseus Mining Limited (ASX/TSX: PRU) has forged a reputation as one of the West Africa s most successful gold explorers. Focused on under-explored gold belts in West Africa, Perseus is on track to become a producer during 2011 at its Central Ashanti Gold Project in Ghana. It is also working on a definitive feasibility study at its Tengrela Gold Project in Ivory Coast, subject to which production is targeted for late 2012. The information in this news release that relates to Mineral Resources is based on information compiled by Mr Paul Payne, who is a Member of The Australasian Institute of Mining and Metallurgy. Mr Payne is an employee of Runge Limited. Mr Payne has sufficient experience, which is relevant to the style of mineralisation and type of deposit under consideration and to the activity which he is undertaking, to qualify as a Competent Person as defined in the 2004 Edition of the Australasian Code for Reporting of Mineral Resources and Ore Reserves ) and to qualify as a Qualified Person under National Instrument 43-101 Standards of Disclosure for Mineral Projects ( NI 43-101 ). Mr Payne consents to the inclusion in this news release of the matters based on the information compiled by him in the form and context in which it appears. Pursuant to NI 43-101, a technical report containing the July 2010 estimate described above will be prepared and filed on SEDAR within 45 days. For a description of the effective date, details of the key assumptions, parameters and methods used, and the extent to which the October 2009 estimate of Mineral Resources may be materially affected by any known environmental, permitting, legal, title, taxation, socio-political, marketing or other relevant issues, readers are directed to the technical report entitled Technical Report Tengrela Gold Project, Ivory Coast dated November 30, 2009. For a description of the effective date, details of the key assumptions, parameters and methods used, and the extent to which the July 2010 estimate of Mineral Resources may be materially affected by any known environmental, permitting, legal, title, taxation, socio-political, marketing or other relevant issues, readers are directed to Appendix 1 of this news release. The information in this news release that relates to exploration results under the heading Ongoing Drilling is based on information compiled by Mr Mark Calderwood, who is a Member of The Australasian Institute of Mining and Metallurgy. Mr Calderwood is a Director and full-time employee of the Company. Mr Calderwood has sufficient experience, which is relevant to the style of mineralisation and type of deposit under consideration and to the activity which he is undertaking, to qualify as a Competent Person as defined in the 2004 Edition of the Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves ) and to qualify as a Qualified Person under NI 43-101. Mr Calderwood consents to the inclusion in this news release of the matters based on the information compiled by him in the form and context in which it appears. Caution Regarding Forward Looking Information: This news release contains forward-looking information which is based on assumptions and judgments of management regarding future events and results. Such forward-looking information, includes but is not limited to information with respect to the development of a mine at the Central Ashanti Gold Project, completion of a definitive feasibility study at Tengrela and development of a mine at Tengrela subject to the results of that study. Forward-looking information involves known and unknown risks, uncertainties, and other factors which may cause the actual results, performance or achievements of the Company to be materially different from any anticipated future results, performance or achievements expressed or implied by such forward-looking information. Such factors include, among others, the actual market price of gold, the actual results of current exploration, the actual results of future exploration, changes in project parameters as plans continue to be evaluated, as well as those factors disclosed in the Company's publicly filed documents. The Company believes that the assumptions and expectations reflected in the forward-looking information are reasonable. Assumptions have been made regarding, among other things, the Company s ability to carry on its exploration and development activities, the timely receipt of required approvals, the price of gold, the ability of the Company to operate in a safe, efficient and effective manner and the ability of the Company to obtain financing as and when required and on reasonable terms. Readers should not place undue reliance on forward-looking information. Perseus does not undertake to update any forward-looking information, except in accordance with applicable securities laws. 5
Appendix 1 Notes on the Sissingue Mineral Resource estimate 1) The Mineral Resource estimate for the Sissingue gold deposit at the Tengrela Gold Project was completed on 16 July 2010 by Runge Limited for Perseus Mining Limited ( Perseus ). Perseus has an 80% interest in the Tengrela Gold Project, which can be increased to 85% through the exercise of an option. 2) The Sissingue deposit is located within altered Lower Proterozoic Biriman (2.17-2.18 billion years) rock of the Syama-Boundiali greenstone belt, comprising undifferentiated granitoids, flysch sediments, intermediate volcanics, and small occurrences of mafic intrusives and molasse sediments. Gold mineralisation at the Project is associated with an altered granitic intrusive, porphyritic dykes and their alteration halo in Lower Proterozoic Birimian metasediments. 3) The drill database for Sissingue for the purposes of the July 2010 Mineral Resource estimate contains 1,285 Reverse Circulation ( RC ) drill holes totalling 103,894m and 119 diamond drill holes totalling 25,578m. Sample recovery is considered to have been to industry standard for both RC and diamond cored drilling. Within the resource wire frames there are 533 RC holes totalling 11,026m and 77 diamond drill holes totalling 4,466m. 4) RC and core drilling was routinely analysed for gold using fire assay and BLEG methods. Standards, spikes, blanks and repeat samples have been randomly submitted during all drilling programs. Sufficient QAQC and data validation has been carried out to verify the integrity of the assay data. 5) The relative position of all drill hole collars is related back to the original project grid using a total station theodolite. Holes are considered to be accurate to within 1m horizontally and 0.5m vertically. The surface topography of the deposits used for resource modelling was generated using lattice gridding of survey data points and is considered to be sufficiently accurate for the generation of an Indicated and Inferred Mineral Resource estimate. Down-hole surveying is routinely used in the deeper percussion drilling and diamond core holes. The down-hole sample location data for the Sissingue deposit is considered adequate to allow for the estimation of Measured, Indicated and Inferred Mineral Resources. 6) Drilling was carried out along east-west fences which were nominally spaced at 20 to 40 metre intervals with holes at 15 to 40 metre centres. All drill-holes were inclined at between 50 and 60 at grid east and west azimuths. The gold value used for plotting and grade estimation was the first fire assay determination presented by the laboratory. 7) Bulk densities were assigned to the resource based on the results of 97 bulk density determinations within the mineralised envelope. The determinations were recently conducted by Perseus. 8) Wireframes were constructed using cross sectional interpretations based on geology or a nominal 0.5g/t Au cut-off grade. 9) Samples within the wireframes were composited to 2.0m intervals. Multiple high grade cuts applied to various domains ranged from 10g/t to 175g/t Au. 10) A Surpac block model was used for the estimate, with a block size of 20m NS by 5m EW by 10m vertical with sub-cells of 5m by1.5m by 2.5m (y, x, z). 11) The deposits were interpolated using Ordinary Kriging (OK). The estimate was run in three passes. The search ellipse was based on kriging parameters defined from directional variography, and lode geometry. The first pass radius varied from 25m to 100m. The second pass radius varied from 45m to 120m and a third and final pass radius varied from 75m to 150m. The majority of blocks were estimated in the first two passes. 6
12) The Mineral Resource was classified as Measured, Indicated and Inferred based on the quality of the drilling data and the demonstrated geological and grade continuity defined by recent drill programs. 13) To the best of their knowledge, Perseus Mining Limited and Runge Limited are not aware of any environmental, permitting, legal, title, taxation, socio-political, marketing or other relevant issues which may materially affect the July 2010 estimate of Mineral Resources. No assumptions have been made about the mining and processing methods likely to be employed at the Sissingue deposit. 7