Aura Minerals Inc.
TSX : ORA

Aura Minerals Inc.

September 20, 2010 17:07 ET

Aura Minerals Announces New Resource Estimate for the Aranzazu Project

VANCOUVER, BRITISH COLUMBIA--(Marketwire - Sept. 20, 2010) - Aura Minerals Inc. ("Aura Minerals" or the "Company") (TSX:ORA) is pleased to announce that a new resource estimate has been completed for its wholly-owned Aranzazu Project in Zacatecas State, Mexico.

Table 1 below presents the updated resource estimate for the Aranzazu Project at a 0.5% Cu cut-off and Table 2 shows the resource estimate at a 0.8% Cu cut-off. The cut-off is based on copper values only.

The 0.8% Cu cut-off will be used for reserve definition of the Arroyos Azules, BW, and Mexicana zones, which are the first areas scheduled for mining upon startup of the operation this quarter. The 0.5% Cu cut-off will be used to continue to assess the potential of the project to be ramped up to a bulk underground operation, as results from the ongoing deep drilling program continue to demonstrate significant intercepts at depths significantly below the current resource. The new resource estimate is based on in-fill drilling of the deposit in order to increase the confidence level for the overall system, and ensure a minimum of 25 metre centres for ongoing reserve calculations. Drilling is ongoing, with an additional 205 drill holes completed subsequent to the cut-off date for the new resource estimate, many of which are outside of the current resource envelope, and five drills are currently operating on site. Since taking over the Aranzazu Project in June 2008, the Company has now completed 100,925 metres of drilling. Aura Minerals therefore expects to complete another updated resource estimate in the next four to six months.

Table 1 - Aranzazu Resource Estimate - 0.5% Cu only cut-off

Category Cutoff Tonnes (000) Copper (%) Gold (g/t) Silver (g/t) Copper lbs (000) Gold oz (000) Silver oz (000)
Measured 0.5 6,461 1.12 0.62 11.0 159,667 129.8 2,283
Indicated 0.5 18,523 1.13 0.53 14.1 459,306 314.4 8,374
Measured & Indicated 0.5 24,984 1.12 0.55 13.3 618,973 444.2 10,657
Inferred 0.5 8,130 1.19 0.46 15.6 212,780 119.3 4,085

Table 2 - Aranzazu Resource Estimate - 0.8% Cu only cut-off

Category Cutoff Tonnes (000) Copper (%) Gold (g/t) Silver (g/t) Copper lbs (000) Gold oz (000) Silver oz (000)
Measured 0.8  3,810  1.46  0.75 13.5  122,900  92.0  1,650
Indicated 0.8  10,362  1.51  0.67 18.0  345,941  223.7  5,987
Measured & Indicated 0.8  14,172  1.50  0.69 16.8  468,841  315.7  7,637
Inferred 0.8  4,940  1.54  0.59  20.3  168,183  93.7  3,222

The copper grades of the measured and indicated resources for the 0.5% Cu cut-off and the 0.8% Cu cut-off estimates have improved by 11% and 12% respectively over the previous resource estimate. Furthermore, most of the historical (pre-2007) drilling on the Aranzazu Project was not assayed for precious metals. Up to the cut-off date for the new resource estimate, Aura Minerals had completed a total of 50,208 metres of drilling, all of which has been assayed for precious metals. In the compilation of this most recent resource estimate, approximately 54% of the holes comprising the resource were assayed for gold, and approximately 64% of the holes comprising the resource were assayed for silver. As compared to the November 2009 resource estimate, the gold grade of measured and indicated resources at a 0.8% Cu cut-off has increased 38%, and the silver grade of measured & indicated resources at a 0.8% Cu cut-off has increased 41%. As drilling continues on the project, precious metals grades in future resource estimates are likely to continue to improve.

Commenting on the new resource estimate, Mr. Patrick Downey, President and CEO of Aura Minerals, stated, "We are very pleased with the results of the new resource update. We have seen a significant increase in measured resources over the previous resource estimate, the copper grades have improved, and the precious metals grades have improved substantially. We expect precious metals grades will continue to improve as drilling progresses. We have continued to advance the mine development and plant upgrades towards a startup of operations at the end of this quarter. We have now commissioned the crushing plant with ore and are currently water commissioning the grinding and flotation sections of the mill. The operation is expected to ramp up to a throughput of 2,600 tonnes per day in the first quarter of 2011. Near-term mine planning is based on the updated resource estimate at a 0.8% Cu cut-off grade, and mine design is based on the Arroyos Azules, Mexicana and BW Zones, which are near existing infrastructure and are now well defined by recent Aura Minerals drilling.

However, with the wide and continuous mineralization system, suitable ground conditions and the fact that the Aranzazu Project has a large and expanding resource base open along strike and at depth, the Company plans to commence studies in the fourth quarter of this year on staged mine and plant expansions. The expansion would be based on a low cost bulk mining scenario such as a combination of sub-level caving and long-hole stoping. The deep drilling program is ongoing and we expect that the next results from this drilling will be available during the fourth quarter."

Quality Assurance and Quality Control ("QA/QC") Procedures for the Aranzazu Project

The resource estimation has been prepared by Aura Minerals, under the direction of William J. Lewis, B.Sc., P.Geo. of Micon International Limited, an independent Qualified Person for the purpose of NI 43-101. A report under NI 43-101, disclosing the updated resource for the Aranzazu Project, is being prepared by Micon International Limited Inc. and will be filed by Aura Minerals on SEDAR within 45 days. Mr. Lewis has also reviewed and approved the contents of this news release as applicable.
The mineral resource for the Aranzazu Project was estimated by ordinary kriging for copper, gold and silver constrained by six 3D solid models based on a 0.30% Cu grade shell within the skarn complex. Block dimensions were 5 x 5 metres horizontal and 5 metres vertical. The deposit has been tested by 855 core holes and 136 reverse circulation holes drilled between 1963 and May 2010. Grade estimation was based on analyses of 20,272 two-metre composites from 851 drill holes. Statistical analysis indentified high-grade outlier composites and a total of 87 Cu, 58 Au and 119 Ag composites were capped. Capping reduced the total Cu metal content by 2% and the total Au and Ag metal content by 3%.

Exploration at the Aranzazu Project is being conducted under the supervision of Alan Hitchborn, PGeo, who is the Company's qualified person as defined by National Instrument 43-101. Mr. Hitchborn has also reviewed and approved the contents of this news release as applicable.

Aura Minerals is presently drilling at the Aranzazu Project using both core and reverse circulation drill rigs. The drilling is conducted by Layne de Mexico. The reverse circulation drill uses a bit sized from 5.5 inches to 4.75 inches. The core program uses HQ-sized core and then stepping down to NQ-sized core as required. Samples are collected on a 1.5-metre sample interval. The reverse circulation drill cuttings are split at the drill rig. The samples collected consist of an approximate 25-percent split of the total material recovered from the interval sampled. This material is shipped directly to the Stewart Group de Mexico sample preparation facility in Zacatecas, Mexico, and processed using the same sample preparation protocol as used for the core samples discussed below. Assays are completed at the ISO 9001-2008-certified Eco Tech Laboratory Ltd., a subsidiary of the Stewart Group Ltd., in Kamloops, B.C., Canada. Diamond drilling core is logged, photographed and then split in half using a diamond core saw. Half the core is retained off-site in a secure storage facility, and the other half is sampled, secured in sealed, labelled bags and then transported to the Stewart Mexico facility in Zacatecas, Mexico, and processed using the same preparation protocol discussed below. Assays are completed at the Eco Tech Stewart laboratory in Kamloops, B.C. The entire half-core and reverse circulation drill cuttings are crushed to 95 percent passing two millimetres, split and pulverized to 95 percent passing 150 mesh, split again, and a 150-gram sample sent for assay. Gold assays are determined by fire assay with an AA finish, over-limit assays are determined by fire assay with a gravimetric finish. Silver, copper, lead and zinc assays are determined by a four-acid digestion with an ICP-MS finish. Molybdenum assays are determined by aqua regia digestion followed by an ICP-OES finish. Silver over-limits are determined by a fire assay with a gravimetric finish. The Company systematically inserts certified standard samples, sample duplicates in a non-sequential order and blank samples in all batches of samples sent to Stewart Mexico and Eco Tech Stewart as a means of quality control. Additionally, Stewart Mexico and Eco Tech Stewart have their own stringent internal QA/QC protocols. Check samples are systematically sent to the ALS Chemex lab in Vancouver, Canada. Chain of custody of drill samples is maintained throughout the process with the use of numbered seal tags closing sample bags and third party professional transportation of samples to the laboratories. Each stage of sample handling is recorded in log sheets and receipts obtained from each party involved.

About Aura Minerals Inc.

Aura Minerals is a Canadian mid-tier gold production company focused on the acquisition, exploration, development and operation of gold and base metal projects in the Americas. The Company's producing assets includes the San Andres gold mine in Honduras, and the recently acquired, Sao Francisco and Sao Vicente gold mines in Brazil. The Company is also developing the copper-gold-silver Aranzazu Project in Zacatecas state in Mexico, which will commence operation in the second half of 2010. Other significant assets include the feasibility-stage Serrote Deposit at the copper-gold-iron ore Arapiraca Project in Brazil.

For further information, please visit Aura Minerals' web site at www.auraminerals.com.

Cautionary Statement

This news release contains forward-looking statements that are not historical facts. Forward-looking statements involve risks, uncertainties and other factors that could cause actual results, performance, prospects and opportunities to differ materially from those expressed or implied by such forward-looking statements. Factors that could cause actual results to differ materially from these forward-looking statements include those risks set out in Aura Minerals' public documents filed on SEDAR at www.sedar.com. Although Aura Minerals believes that the assumptions and factors used in preparing the forward-looking statements are reasonable, undue reliance should not be placed on these statements, which only apply as of the date of this news release, and no assurance can be given that such events will occur in the disclosed time frames or at all. Aura Minerals disclaims any intention or obligation to update or revise any forward-looking statement, whether as a result of new information, future events or otherwise.

No stock exchange, securities commission or other regulatory authority has approved or disapproved the information contained herein.

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