Greystar Resources Announces Updated Resource for the Angostura Gold-Silver Deposit, Colombia

 
TIDMGSL 
 
Greystar Resources Announces Updated Resource for the Angostura Gold-Silver Deposit, Colombia 
FOR:  GREYSTAR RESOURCES LTD. 
 
TSX, AIM SYMBOL:  GSL 
 
July 15, 2010 
 
Greystar Resources Announces Updated Resource for the Angostura Gold-Silver Deposit, Colombia 
 
VANCOUVER, BRITISH COLUMBIA--(Marketwire - July 15, 2010) - Greystar Resources Ltd. (the "Company") (TSX:GSL)(AIM:GSL) is pleased to announce an updated resource calculation for the Company's Angostura gold and silver deposit located in the California mining district in Colombia. The resource study is based on updated 3D geological and mineral models, and includes all of the technical data available as of January 2010, including 179,813 core assays from 938 drill holes representing 302,834 metres, and 1,768 muck samples from the exploration tunnels. The resource study was developed by Greystar under the overall supervision of consulting company NCL Ingenieria y Construccion S.A. (NCL) from Santiago, Chile. 
 
Additional drilling carried out in 2008 and the rigorous evaluation of the resource by Greystar's geological staff working closely with NCL has provided a robust resource model for the Feasibility study (FS). Greystar has initiated the evaluation of underground resources that lie beyond the FS pit boundary but within a proximity to allow exploitation utilizing the pit infrastructure either during or after completing the open pit operation. As the cut-off date for the data employed in these resource study was January 2010, not all of the recent Los Laches drilling data has been included. The evaluation of underground potential at Angostura is a work in progress, however early indications are that underground resources could have a meaningful impact on the project. 
 
Resource Highlights: 
 
Operational Pit(i) Resource 
 
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Measured and indicated resource of 8.9 million ounces gold and 59.6 million 
ounces of silver 
Additional inferred resource of 903,000 ounces of gold and 4.7 million 
ounces of silver 
(i)An operational pit was designed by NCL using mining, metallurgical and 
geotechnical parameters available. 
 
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Underground Resource 
 
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Measured and indicated resource of 831,000 ounces gold and 3.8 million 
ounces of silver 
Additional inferred resource of 437,000 ounces of gold and 2.0 million 
ounces of silver 
 
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Operational Pit Resource 
 
(i)An operational pit was designed by NCL using mining, metallurgical and geotechnical parameters available. 
 
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              ------------------------------------------------------------ 
                                        Category 
              ------------------------------------------------------------ 
                                                        Total 
                     Measured      Indicated   (Meas. + Ind.)     Inferred 
  ------------------------------------------------------------------------ 
                                   OXIDES 
  ------------------------------------------------------------------------ 
  Kt                   79,160         26,597          105,757        6,306 
  ----------------------------------------------------------- ------------ 
  Au (g/t)               0.39           0.45             0.41         0.44 
  ----------------------------------------------------------- ------------ 
  Ag (g/t)                  3              3                3            3 
  ----------------------------------------------------------- ------------ 
  Au (koz)                998            389            1,387           88 
  ----------------------------------------------------------- ------------ 
  Ag (koz)              8,521          2,787           11,308          555 
  ----------------------------------------------------------- ------------ 
                                 TRANSITION 
  ------------------------------------------------------------------------ 
  Kt                  104,003         20,758          124,761        5,523 
  ----------------------------------------------------------- ------------ 
  Au (g/t)               0.61           0.89             0.66         0.84 
  ----------------------------------------------------------- ------------ 
  Ag (g/t)                  6              6                6            6 
  ----------------------------------------------------------- ------------ 
  Au (koz)              2,039            594            2,633          149 
  ----------------------------------------------------------- ------------ 
  Ag (koz)             19,373          4,163           23,536        1,111 
  ----------------------------------------------------------- ------------ 
                                  SULPHIDES 
  ------------------------------------------------------------------------ 
  Kt                   94,505         33,540          128,045       14,519 
  ----------------------------------------------------------- ------------ 
  Au (g/t)               1.00           1.75             1.20         1.43 
  ----------------------------------------------------------- ------------ 
  Ag (g/t)                  5              8                6            6 
  ----------------------------------------------------------- ------------ 
  Au (koz)              3,036          1,885            4,921          666 
  ----------------------------------------------------------- ------------ 
  Ag (koz)             16,118          8,635           24,753        2,996 
  ----------------------------------------------------------- ------------ 
                     TOTAL RESOURCES IN OPERATIONAL PIT 
  ------------------------------------------------------------------------ 
  Kt                  277,668         80,895          358,563       26,348 
  ----------------------------------------------------------- ------------ 
  Au (g/t)               0.68           1.10             0.78         1.07 
  ----------------------------------------------------------- ------------ 
  Ag (g/t)                  5              6                5            6 
  ----------------------------------------------------------- ------------ 
  Au (koz)              6,074          2,868            8,942          903 
  ----------------------------------------------------------- ------------ 
  Ag (koz)             44,012         15,585           59,597        4,662 
  ------------------------------------------------------------------------ 
 
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Underground Resource 
 
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              ------------------------------------------------------------ 
                                        Category 
              ------------------------------------------------------------ 
                                                        Total 
                     Measured      Indicated   (Meas. + Ind.)     Inferred 
  ------------------------------------------------------------------------ 
                                  SULPHIDES 
  ------------------------------------------------------------------------ 
  Kt                    1,283          4,761           6,044         3,762 
  ----------------------------------------------------------- ------------ 
  Au (g/t)               3.95           4.36            4.28          3.61 
  ----------------------------------------------------------- ------------ 
  Ag (g/t)                 17             20              19            16 
  ----------------------------------------------------------- ------------ 
  Au (koz)                163            668             831           437 
  ----------------------------------------------------------- ------------ 
  Ag (koz)                718          3,067           3,785         1,992 
  ------------------------------------------------------------------------ 
 
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Resource Estimate Methodology 
 
To generate the Mineral Resource Estimate the following data and methods were used: 
 
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=-  Mineral resources were estimated in conformance with the CIM Mineral 
    Resource and Mineral Reserve definitions referred to in National 
    Instrument 43-101, Standards of Disclosure for Mineral Projects. 
 
=-  The resource study is based on an updated 3D geological and mineral 
    model, and includes all of the technical data available as of January 
    2010, including 179,813 core assays from 938 drill holes accumulating 
    302,834 meters, and 1,768 muck samples from the exploration tunnels. 
 
=-  A review of the QA/QC database showed adequate levels of quality for the 
    resource estimate. 
 
=-  The resource model also includes a total of nearly 9,000 specific 
    gravity measurements from drill core. The bulk densities for oxides, 
    transition and sulfides were obtained applying appropriate factors of 
    correction to the specific gravity mean values. 
 
=-  Three oxidation alteration levels were defined, oxide, transition and 
    sulfide. The oxide material is defined where the sulfide minerals have 
    been completely or nearly completely oxidized. The transition material 
    is characterized by the coexistence of original sulfides with variations 
    in limonite content as the main indicator of oxidation level; and the 
    sulfides or "fresh" material where the oxidation has not affected the 
    rock. 
 
=-  The current model has used structural trend surfaces that follow the 
    interpreted veins throughout the deposit. The trend surfaces guide the 
    direction of the three axes of the search ellipsoid used for grade 
    interpolation on a local scale and assure that the geological influence 
    on the grade interpolation is preserved. 
 
=-  All gold assay data was split into two populations, high-grade and low- 
    grade, using a threshold of 5 g/t gold. Both populations were composited 
    to intervals of 2 meters, and grade capping was applied to the 
    composites. Capping levels for the high-grade population was 50 g/t, Au 
    for all the structural domains, 350 g/t Ag for the domains of Veta de 
    Barro and Cristo Rey, 450 g/t Ag for the domains of Perezosa fault, 
    Silencio - Laches and for Central area. 
 
=-  The block model uses regular blocks of 6 x 6 x 6 metres constructed 
    using the software Datamine. Search distances for the probability and 
    grade interpolation are supported by variography results. The 
    probability of a block to contain high-grade mineralization was 
    interpolated using an indicator approach which applied a floating 
    ellipsoid with radii developed for five different domains. The 
    probability interpolation used an inverse distance to the twelfth (ID12) 
    power to minimize undue grade projection. As a result of the probability 
    interpolation, each block contains an estimate of the volume of high- 
    grade and of the volume of low-grade mineralization. To avoid over 
    estimating of high grade, a 30-metre radius was used to restrict the 
    impact of the high grade. 
 
=-  The grade interpolation was undertaken weighing the grade information by 
    the inverse of the square of the distance to the block being estimated 
    (ID2). In a first interpolation step, the low grade material in each 
    block was interpolated from surrounding low grade composites using 
    ellipses for the first search with a radius between 30 to 50 metres in 
    strike and between 30 and 62.5 m in dip, depending on the domain, and a 
    fixed 6 metres for cross strike in both searches; while the second 
    search corresponding to the range of the variograms, being 2 times the 
    first one. The grade of the high grade material in each block was 
    interpolated from surrounding high grade composites using the same 
    search ellipsoids as were used for the probability interpolation. A 
    second grade interpolation step followed for which the ellipsoid axes 
    were doubled. Blocks beyond the reach of this larger search were not 
    estimated. 
 
=-  The classification of the resources was based primarily on the number of 
    drill holes used for the interpolation. The requirement for measured 
    resources is to require at least 2 drill holes in the first search 
    ellipsoid (50% of the range of the variograms). For indicated, at least 
    1 drill hole is required using the first search ellipsoid. The material 
    interpolated with the second search ellipse, formed by 100% of the range 
    of the variogram, was classified as inferred. These classification 
    parameters are considered appropriate according to the intensity of the 
    drilling and the continuity of the mineralization in the ore body. 
 
=-  For the resources reported for US$850/oz Au and US$ 12/Oz Ag, an 
    operational pit was designed by NCL using mining, metallurgical and 
    geotechnical parameters available. 
 
=-  The portions of the block model beneath these operational pits were 
    examined to determine the zones which might support the necessary 
    capital for development. The portions that were too isolated or with 
    insufficient grade or tonnage for underground mining were categorized as 
    waste. 
 
=-  The open pit and underground resources are reported using an incremental 
    cut off grade, where each block in the model is economically evaluated 
    using the gold and silver prices, metallurgical model and processing 
    costs. The blocks with positive revenue are considered mineral. This 
    methodology is more rigorous than simply applying an overall cut off 
    grade. 
 
 
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The above information has been reviewed and approved by Mr. Rodrigo Mello, Senior Geologist with NCL Ingenieria y Construccion S.A., Santiago, Chile a "qualified person" as that term is defined in National Instrument 43-101 and Guidance Note for Mining, Oil and Gas Companies issued by the London Stock Exchange in respect of AIM companies, which outline standards of disclosure for mineral projects. The complete NI 43-101 compliant Technical Report will be filed on SEDAR at www.SEDAR.com within 45 days. 
 
Glossary of Key Terms 
 
Block Model -- The sub-division of a mineral deposit into a regular, three-dimensional grid of blocks. The grade of each block is estimated from a set of nearby sample values. 
 
Contained Ounces, Contained Gold -- Represents ounces in the ore before losses during the applicable metallurgical process. 
 
Cut-off Grade -- The minimum grade at which a unit of ore will be mined or treated. At the cutoff grade, the value is equal to the costs associated with mining and/or treating the unit of ore. 
 
Dilution -- The effect of waste or low-grade material which is unavoidably included in the mined ore, lowering the mining grade. 
 
Grade -- The amount of metal in each ton of ore, expressed as grams per tonne for precious metals (or as troy ounces per short ton in the imperial system), and as a percentage for most other metals. 
 
Mineral Resource -- A mineral resource is a concentration or occurrence of natural, solid, inorganic or fossilized organic material in or on the Earth's crust in such form and quantity and of such a grade or quality that it has reasonable prospects for economic extraction. The location, quantity, grade, geological characteristics and continuity of a mineral resource are known, estimated or interpreted from specific geological evidence and knowledge. Mineral resources are sub-divided, in order of increasing geological confidence, into inferred, indicated and measured categories. 
 
Inferred Mineral Resources -- An inferred mineral resource is that part of a mineral resource for which quantity and grade or quality can be estimated on the basis of geological evidence, limited sampling and reasonably assumed but not verified geological and grade continuity. The estimate is based on limited information and sampling gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes. 
 
Indicated Mineral Resource -- An indicated mineral resource is that part of a mineral resource for which quantity, grade or quality, densities, shape and physical characteristics can be estimated with a level of confidence sufficient to allow the appropriate application of technical and economic parameters, to support mine planning and evaluation of the economic viability of the deposit. The estimate is based on detailed and reliable exploration and testing information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes that are spaced closely enough for geological and grade continuity to be reasonably assumed. 
 
Measured Mineral Resources -- A measured mineral resource is that part of a mineral resource for which quantity, grade or quality, densities, shape and physical characteristics are so well established that they can be estimated with confidence sufficient to allow the appropriate application of technical and economic parameters, to support production planning and evaluation of the economic viability of the deposit. The estimate is based on detailed and reliable exploration, sampling and testing information gathered through appropriate techniques from location such as outcrops, trenches, pits, workings and drill holes that are spaced closely enough to confirm both geological and grade continuity. 
Mineral resources, which are not mineral reserves, do not have demonstrated economic viability. 
 
Tonne -- Equal to 1,000 kilograms. 
 
Underground -- Where the minerals are explored or mined entirely from tunnels, shafts or drifts. 
 
About Greystar Resources Ltd. 
 
Greystar Resources Ltd. is a precious metals exploration and development company that is currently completing a feasibility study on its wholly owned, multi-million ounce Angostura gold-silver deposit in northeastern Colombia. A positive prefeasibility study announced on March 25, 2009 envisions average annual production at Angostura of 511,000 ounces of gold and 2.3 million ounces of silver over a 15 year mine life. 
 
Forward-Looking Statements 
 
Certain statements in this news release are "forward-looking" within the meaning of Canadian securities legislation. They include statements about future management and the Company's anticipated transition from a gold exploration company to a gold production company. Forward-looking statements are necessarily based upon a number of estimates and assumptions that, while considered reasonable by the Company, are inherently subject to significant business, economic, competitive, political and social uncertainties and other contingencies. Many factors could cause the Company's actual results to differ materially from those expressed or implied in the forward-looking statements. These factors include, among others, conclusions or realization of mineral resources, the actual results of exploration activities, possible variations in ore grade or recovery rates, fluctuations in the price of gold and silver, risks relating to additional funding requirements, political and foreign risks, production risks, environmental regulation and liability, government regulation as well as other risk factors set out under the heading "Risk Factors" in the Annual Information Form dated March 26, 2010 which is available on SEDAR at www.sedar.com. Investors are cautioned not to put undue reliance on forward-looking statements due to the inherent uncertainty therein. 
 
 
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FOR FURTHER INFORMATION PLEASE CONTACT: 
 
Greystar Resources Ltd. 
Geoff Chater 
[phone] 
[e-mail] 
www.greystarresources.com 
 
OR 
 
Renmark Financial Communications Inc. 
John Boidman 
Investor Relations Contact 
[phone] or [phone] 
[e-mail] 
 
OR 
 
Renmark Financial Communications Inc. 
Dan Symons 
Investor Relations Contact 
[phone] or [phone] 
[e-mail] 
www.renmarkfinancial.com 
 
OR 
 
NCB Stockbrokers Limited 
Christopher Caldwell 
London NOMAD Contact 
[phone] 
[e-mail] 
 
Neither the Toronto Stock Exchange nor the AIM Market of the London Stock Exchange has reviewed and neither accepts responsibility for the adequacy or accuracy of this news release. 
 
 
Greystar Resources Ltd.