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Dia Bras Obtains 85% Recovery of Silver from Cusi Rocks
Montréal, Québec, June 10, 2009 -
Dia Bras Exploration Inc. (TSX-V: DIB) (“Dia Bras” or the “Company”) is pleased to report the results of metallurgical testing on silver-mineralized rock from its Cusi project. The testing was done under the direction of an independent engineer, Sr. Pedro Castillo C., at the Centro de Investigatíon de Materiales Avanzados (CIMAV) located in Chihuahua City, Chihuahua.
A representative sample was collected under the supervision of Sr. Castillo from 1,500 tonnes of rock (mined from the Santa Eduwiges and Santa Marina veins) stockpiled at the Company’s Malpaso mill. The sample was reduced to 5 kg mass and processed using a combination of flotation and cyanidation methods. The results are shown in the tables below:
Flotation Method
Product |
Mass |
Mass |
Assay Results |
Percent Recovery |
||
grams |
% |
Ag, g/t |
Pb% |
Ag |
Pb |
|
Concentrate |
232.8 |
4.62 |
3743.2 |
53.91 |
54.96 |
59.6 |
Flotation tails |
4808.7 |
95.38 |
148.5 |
1.77 |
45.04 |
4041 |
Cyanidation Method
Pregnant Solution |
|
99.0 |
|
66.7 |
|
|
Residual Tails |
4808.7 |
95.38 |
49.5 |
|
33.30 |
|
Total Recovery |
|
85.00 |
59.6 |
Calculated Head |
5041.5 |
100.0 |
314.5 |
4.18 |
100.0 |
100.0 |
Sr. Castillo also took photomicrographs of flotation concentrates that show grains about 100 microns in size (~140 mesh or 0.1 mm) of interlocked sphalerite and galena. From this information, it has been determined that the best economic grind for Cusi rock is 50% passing 200 mesh (-0.074 mm) and that reagents of zinc sulfate and cyanide during flotation recovery will reduce zinc contents in the lead-silver concentrates.
Bottle roll tests of cyanide leaching show that 80% of silver in the tails is recovered in 16 hours, and that continuing the tests to 48 hours resulted in 83% recovery of silver, an increase of only 3%. These results indicate that cyanide-recoverable silver is captured in a short time and that longer residence time is not worth the cost.
Based on these metallurgical data, management has decided to re-start pilot mining at Cusi during August, 2009, and process the mineralized rock by flotation method and stockpile the flotation tails while cyanidation vats are being constructed. The vats will be completed within 6 months from the start of construction. Application for permits for cyanidation processing has been made and management expects approval within six months.
Similar metallurgical tests have been initiated on rock from the Promontorio mine as management expects to initiate pilot mining of this deposit during the third quarter of 2010.
Bolivar Production
Further to its May 29, 2009 news release, the transportation of mineralized rock from the Bolivar Mine to the Malpaso mill has been resumed Tuesday. The management revised its production forecast for Bolivar pilot-mining production to approximately 100,000 tonnes at average grades of 1.47% Cu and 9.16% Zn for 2009.
The technical content of this news release has been approved by Thomas L. Robyn, Ph.D. Chairman of the Board of Dia Bras, a Qualified Person as defined in NI43-101.
Annual General Meeting of Shareholders
The Company invites you to attend its Annual General Meeting of Shareholders to be held at the Delta Hotel, 475 President Kennedy Avenue, Mozart Room, Montréal, Québec, at 10:00 a.m. (local time) today. The Company will present a review of the past year, its first quarter 2009 results and will also provide an update on its business strategy and development projects. The presentation will also be available on Dia Bras’ Website, www.diabras.com.
About Dia Bras
Dia Bras is a Canadian exploration mining company focused on precious and base metals in the State of Chihuahua, in Northern Mexico. The Company is committed to developing and adding value to its assets – the Bolivar copper-zinc project and the Cusi silver mining camp. The Company trades on the TSX Venture Exchange, under the symbol “DIB”.
For further information on Dia Bras visit www.diabras.com or contact:
Daniel Tellechea, |
|
Nathalie Dion |
Neither the 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.
Forward-looking statements:
Except for statements of historical fact all statements in this news release without limitation regarding new projects acquisitions future plans and objectives are forward-looking statements which involve risks and uncertainties. There can be no assurance that such statements will prove to be accurate; actual results and future events could differ materially from those anticipated in such statements.