TORONTO, Sept. 4, 2011 /CNW/ - Gran Colombia Gold Corp. (TSX: GCM, GCM.WT, GCM.WT.A) is pleased to announce a new National Instrument 43-101 mineral resource estimate for its Marmato Project containing 10.0 million ounces of gold in the Measured and Indicated categories and an additional 2.4 million ounces of gold in the Inferred category at a cut-off grade of 0.3 g/t (see table below). In addition, there are an estimated 64 million ounces of silver in the Measured and Indicated categories and a further 11 million ounces of silver in the Inferred category. This new in-pit mineral resource represents a 51% increase in measured and indicated gold ounces and a 73% increase in measured and indicated silver ounces compared to the previous mineral resources dated January 6, 2011.

Commenting on these results, Serafino Iacono, Executive Co-Chairman of Gran Colombia noted, "We are extremely pleased with the success of our infill drilling program, which has significantly increased both the quantity and the quality of our mineral resources, as well as the overall gold grade, all of which will be incorporated in the pre-feasibility study that is currently underway."

In addition to this in-pit resource, SRK Consulting (UK) Ltd., which performed the mineral resource estimate, has also identified an underground mining resource of 2.1 million tonnes at a gold grade of 1.8 grams per tonne representing 120,000 ounces of Measured and Indicated gold resources plus 6.4 million tonnes grading 2.3 g/t gold or 500,000 ounces of gold in the Inferred resource category.

The above estimate is based on over 180,000 metres of diamond drilling and cross-cut samples. The updated estimate reflects results from an additional 157 drill holes or 52,500 metres, plus 732 metres of cross-cut sampling, collectively representing a 53% increase in the assay database since the previous mineral resource estimate was announced.

The complete NI 43-101 Technical Report will be filed within 45 days and will be available on the Company's website and www.sedar.com. A webcast/conference call will be scheduled at that time to provide further details about this updated resource.

In May of this year, the Company filed a Preliminary Economic Assessment, also prepared by SRK, indicating that the preferred mining method is open pit with contractor mining.  Based on processing 283 million tonnes of ore at a rate of 40,000 tonnes per day, production would average 340,000 ounces of gold and 1.3 million ounces of silver per year over a 21-year mine life.  The cash operating cost is expected to be US$524 per ounce of gold, net of silver credits. Assuming a life of mine capital cost of US$550 million, total cost per ounce is estimated to be US$643.  These estimates assume an average gold grade of 0.9 g/t, a stripping ratio of 3.3:1 and a metallurgical recovery of 88% for gold and 60% for silver.  The complete Preliminary Economic Assessment is available on www.sedar.com as well as the Company's website.

Gran Colombia has retained the services of Hatch Ltd. to conduct a Pre-feasibility Study for the Marmato project utilizing the mineral resources reported today, with the final report expected in the first quarter of 2012.

Qualified Person:

Ben Parsons, Senior Resource Geologist with SRK Consulting (UK) Ltd. prepared the Marmato Project mineral resource estimate. For detailed information on the key assumptions, parameters and methods used to estimate the mineral resources, along with other information about the properties, please refer to the Technical Report.

About Gran Colombia Gold Corp.

Gran Colombia is a Canadian-based gold and silver exploration, development and production company with its primary focus in Colombia.  Gran Colombia is currently the largest underground gold and silver producer in Colombia with six underground mines in operation.  In addition, Gran Colombia is also developing a large-scale, open-pit gold and silver mine at Marmato.  The Company also has a highly-prospective land position in Colombia as well as an advanced stage property in Venezuela and earlier stage properties in Mali.

Additional information on Gran Colombia can be found on its website at www.grancolombiagold.com and by reviewing its profile on SEDAR at www.sedar.com.

Cautionary Statement on Forward-Looking Information:

This news release contains "forward-looking information", which may include, but is not limited to, statements with respect to the future financial or operating performance of the Company and its projects. Often, but not always, forward-looking statements can be identified by the use of words such as "plans", "expects", "is expected", "budget", "scheduled", "estimates", "forecasts", "intends", "anticipates", or believes" or variations (including negative variations) of such words and phrases, or state that certain actions, events or results "may", "could", "would", "might" or "will" be taken, occur or be achieved. Forward-looking statements involve known and unknown risks, uncertainties and other factors which may cause the actual results, performance or achievements of Gran Colombia to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements. Forward-looking statements contained herein are made as of the date of this press release and Gran Colombia disclaim, other than as required by law, any obligation to update any forward-looking statements whether as a result of new information, results, future events, circumstances, or if management's estimates or opinions should change, or otherwise. There can be no assurance that forward-looking statements will prove to be accurate, as actual results and future events could differ materially from those anticipated in such statements. Accordingly, the reader is cautioned not to place undue reliance on forward-looking statements.