Dia Bras Exploration Inc.

Dia Bras Exploration Inc.

December 17, 2008 12:26 ET

Dia Bras Applies New Geologic Model at Bolivar and Produces High-Grade Intercepts in the Newly Discovered Guadalupe Area

MONTREAL, QUEBEC--(Marketwire - Dec. 17, 2008) - Dia Bras Exploration Inc. (TSX VENTURE:DIB) ("Dia Bras") is pleased to provide an update from its exploration works carried out at the Bolivar Mine in the State of Chihuahua, Mexico. New high-grade intercepts from underground exploration led to the discovery of two new mineralization zones within 100 metres of the existing workings.

Sharp decreases in base metal price during the third quarter 2008 required dramatic changes in both exploration and operational strategy for Dia Bras' pilot-mining efforts at the Bolivar Mine. Changes required application of new exploration concepts to find high-grade mineralization in proximity to existing workings, a new operational model to utilize production platforms as a base for drilling, and knowledge of district habit, structure, mineralization and alteration to identify specific targets.

Geologic Model

Massive copper-zinc sulfide bodies, known as "chimneys" and "runs" after similar structures in the Main Tintic and Gilman Districts in the United States, define the form and geometry of Bolivar mineralization. Both replace garnet pyroxene metasomatized carbonate rocks and form vertical, irregular shaped chimneys and WNW finger-shaped bodies that occupy the 450-metre-wide WNW Bolivar shear zone (the composite plan is available at the following address: http://media3.marketwire.com/docs/Guadalupe_Area_Dia_Bras.pdf). Runs plunge gently ESE toward a regional scale, NW structure known as the "Banda" fault.

Chimneys form where north-trending structures and dikes intersect the carbonate section to form vertical columns of broken and brecciated rock. High-grade massive copper-zinc mineralization occurs where garnet-pyroxene skarn replaces the brecciated carbonate rock columns. Copper-zinc runs originate at chimneys and plunge gently ESE downdip and away from their chimneys in garnet-pyroxene skarn, following the intersection of favorable carbonate beds with faults and fractures of the Bolivar shear.


A variety of exploration styles have been employed in the district since 1965 with Minera Frisco SA de CV who made a district scale reconnaissance geologic map. In 2006, a second detailed and thorough geological map was realized over 60% of the district by Dia Bras geologists. Both maps still guide district thinking. Drilling programs ranged from fan and spray holes that tested individual targets underground to a geostatistically guided grid drilling program over the property that met with limited success.

One particularly successful program that led to the discovery of the Brecha Linda Manto by Dia Bras in 2004 utilized surface geochemistry to see through overlying andesite. Dia Bras has been particularly fortunate to have had numerous visits by the noted skarn expert Prof. Larry Meinert who saw the district develop over the past five years and made numerous critical observations and recommendations, many of which need yet to be implemented.

In the third quarter of 2008, an evaluation of Dia Bras' exploration was initiated after completion of the 2008 resource drilling program. One aspect noted for pilot-mining activities to date is that underground exploration and stope development costs were inordinately high due to the large metreages of core drilling and drifting used to lay-out stopes. One example is in the San Francisco test stope where over 7,500 metres of hole advanced to develop this ground. In spite of this volume of exploration drilling, short "buggy holes" defined mineralization for test stopes. Approximately 900 metres of "buggy drilling" is conducted monthly for stope layout and production development. In addition, previous surface drilling required long holes just to reach productive horizons and yielded less than 10% discovery rate.

Dia Bras is now applying underground exploration methods of the types that were extremely successful in the Tintic district for over 100 years to explore close to workings and staying one step ahead of operations. Tintic operators drilled down plunge along "ore run" structures to their large-tonnage, high-grade chimney sources.

As at Tintic, multi-metre intercepts at Bolivar of greater than 10% copper-zinc mineralization have produced successful pilot-mining results. The Tintic strategy of combined exploration and operations eliminates the necessity of multiple, costly holes from surface and thousands of metres of overdrilling and drifting to develop new discoveries underground. For example, the new Guadalupe area is presently being developed with only 1500 metres of core hole drilling and 205 metres of development drift.

Results of fourth quarter mine exploration to date include the discovery of the Guadalupe zone and the Selena extension, two new areas within 100 metres of existing workings (see attached composite plan). Selena mineralization is on the ESE extension of the Fernandez-Selena Run. The Guadalupe area consists of a cluster of three mineralized zones at the structural intersection of the Fernandez-Rebecca Run, downdip projection of the Brecha Linda Manto, the San Angel Dike, and the NW trending Felsic Dike.

The discovered holes by area are as follows:

Underground % % Ag Au
Drill Hole Workplace From To True Width Cu Zn g/t g/t
DB04B102 Brecha Linda 135.0 136.0 1.00 0.54 14.05 20.3 0.05
148.6 153.6 5.00 0.88 8.13 49.9 0.19
166.65 174.6 7.95 0.65 8.01 43.34 0.32
DB04B119 Brecha Linda 118.0 122.0 4.0 1.84 20.24 16.33 0.03
DB08BM189 Brecha Linda 116.7 120.17 3.47 5.98 43.49 74.74 0.13
DB08BM190 San Angel 63.07 64.85 1.78 2.94 18.34 34.48 0.05
75.85 80.3 4.45 2.74 24.14 40.46 0.08
DB08BM196 Selena II 7.55 13.87 6.32 4.63 21.01 68.26 0.07
DB08BM202 Selena II 6.8 16.0 9.2 Massive Cpy, Sph
(Assays Pending)

Ramps to explore and develop these new mineralized areas are advancing on Levels 2 and 7. Ramp 2-840E advanced 65 metres along the southeast contact of the San Angel dike through garnet diopside skarn with massive and disseminated bornite-chalcopyrite-sphalerite mineralization. Ramp 7-940 is planned to advance south from Rebecca to test high-grade intercepts in hole DB08BM189 that underlie the Guadalupe chimney, encountered at the intersection of the San Angel granodiorite dike, the downdip extension of the Brecha Linda Manto, and the Rosario-Rebecca Run.

In the Main Tintic District, specifically five north-south ore runs such as the Mammoth Chief and Gemini were mined for over four kilometres and led miners to eight chimneys such as the Billings, Apex, and Ajax. At Gilman, Colorado four ore runs were mined down plunge for 1.5 kilometres and discovered nine chimneys. Individual targets in these districts produced massive sulfide copper, zinc, silver, gold ores ranging in size when individual ore shoots were totaled from 4 to 20 million tons of high-grade ore. The WNW, ESE orientation of the Bolivar deposit suggests that additional deposits are a prospective downplunge of those discovered to date. Using carbonate hosted models such as those from Tintic, Utah, Gilman, Colorado, and throughout the Mexican chimney and manto base metal silver province, it is believed that the Bolivar district offers the potential for similar large tonnage, high-grade discoveries.

In addition to pilot-mining exploration, larger scale "headframe" exploration is also being done for similar copper-zinc runs and disseminated copper-silver-gold open pittable targets. Current head-frame exploration centers on compilation and re-examination of the Dia Bras database, an evaluation of Dia Bras' extensive core library, application of successful work by Meinert using low-cost alteration mapping and geochemical sampling that will be utilized to define a prioritized target list. Lastly, the precise testing of quality, prioritized drill targets from surface will be completed to add to Dia Bras' current resource base.

Method of analysis

Samples were prepared at the Chemex lab facility in Chihuahua, Mexico, and analyzed by ICP and AA methods at their facilities in Vancouver, Canada. Diamond drill samples sent for analysis consisted of half NQ-size and BQ-size diamond core split on site, prepared by the ALS Chemex sample preparation laboratory in Chihuahua, Mexico, and assayed for Au by 50 g fire assay with AA finish, and for Ag by AA on 50 g split sample at the ALS Chemex North Vancouver Laboratory. Assays for Pb, Zn and Cu are done by Induction Coupled Plasma (ICP) at Chemex.

Quality control

The quality assurance-quality control (QA-QC) of Dia Bras has been described in detail in both Scott Wilson Roscoe Postle Associates 43-101 reports of December 2006 at Cusi and October 2005 for Bolivar.

The technical content of this news release has been approved by Eugene Schmidt, RPG and Vice-President of Exploration and Geology for Dia Bras, a Qualified Person as defined in NI43-101.

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".

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.

The TSX Venture Exchange does not accept responsibility for the adequacy or accuracy of this press release.

Contact Information

  • Dia Bras Exploration
    Daniel Tellechea
    President & CEO
    Dia Bras Exploration
    Eugene Schmidt
    Vice President of Exploration and Geology