Dia Bras Exploration Inc.

Dia Bras Exploration Inc.

September 25, 2007 16:27 ET

Dia Bras Receives NI 43-101 Resources Evaluation on the Bolivar Cu-Zn Project

MONTREAL, QUEBEC--(Marketwire - Sept. 25, 2007) - Dia Bras Exploration (TSX VENTURE:DIB) is pleased to announce Mineral Resources for the Bolivar deposit. The Company has received a Resource Evaluation for the Bolivar Cu-Zn Project, dated September 22, 2007; it was conducted by Yann Camus, P.Ing.Geo., from Geostat International, independent Qualified Person under NI 43-101 standards.

"We are pleased with the results of this resource evaluation, which provide the basis for us to initiate our pre-feasibility study for a mill on site at Bolivar" said Dr. Thomas Robyn, Executive Chairman. "With a mill on site, we will have a significant reduction of our production costs, thereby lowering the cutoff grades used in the evaluation with a resultant increase in tonnage."

The Mineral Resources of the Bolivar deposit are contained within two mineralized stratabound zones, the Upper and the Lower Skarn, which display two types of Cu-Zn mineralization: 1) a typical high grade Cu-Zn "manto"-pipe-breccia mineralization (Upper Skarn); and, 2) lower grade Cu-magnetite replacement mineralization (Lower Skarn).

All these resources are contained predominantly within two major mineralized areas, the Bolivar Alta Ley deposit and the El Gallo deposit situated some 500 metres to the south.

The Bolivar Alta Ley includes the Bolivar mine that hosts the 110 degrees Fernandez trend, in which the high grade Selena and Titanic lenses are situated, and the 310 degrees Rosario trend, in which the Breccia Linda, Rosario, Rodolpho, La Foto and San Angel lenses are found (refer to included long section at http://www.ccnmatthews.com/docs/SketchLongSection.jpg).

Geostat has estimated the Mineral Resources of the Bolivar deposit using the database up to July 31st 2007, which includes 306 diamond surface and underground drill holes for a total of 68,218 metres of drilling, which Dia Bras has provided to Geostat and which were loaded in Geostat software. A total of some 10,243 metres of assayed core were used (9,758 samples) for the resources calculation. Drilling is ongoing and resources will be upgraded as new results are made available.

In the El Gallo area, only limited drilling (approx. 8,000 m) has been performed up to present, and the Upper Skarn mineralization appears more subdued and structurally controlled as in the Bolivar mine. However, the Lower Skarn mineralization is very well defined and extends over the entire area.

Resource Evaluation

The Mineral Resources estimate for the Bolivar deposit used a cut-off grade based on average prices for copper, zinc, silver and gold, production costs and expected recovery in the resource model. Geostat has used an over-all recovery of 80% for copper and 90% for zinc. This is based on the two years of production record (February 2005 to July 2007) at the Malpaso mill. Geostat has used the production costs as determined by Dia Bras for underground mining at Bolivar. These costs are reported to be similar to other copper-zinc operations of similar scale in Mexico. At prices of US$2.00/lb. Cu, US$1.00/lb. Zn, US$10.00/oz Ag, US$500/oz Au, the cut-off grade for the Bolivar Upper Skarn deposit resource estimate is calculated as 2.5% Cu Equivalent (% Cueq). Geostat recommends that this cut-off grade be used to report Mineral Resources of the Upper Skarn for processing of rock at the Malpaso mill. The cut-off grade for the Bolivar Lower Skarn deposit resource estimate is variable at this stage, because the Lower Skarn will not be mined until a mill is constructed on site.

The Mineral Resources on the Bolivar Deposit are summarized in the following table:

Table 1

Resources of the Upper Skarn of the Bolivar Project
Calculated by Yann Camus, Geostat Systems International Inc., 2007-09-22
The cutoff grade applied in the Upper Skarn is 2.5% Cueq
Mineralized SG Cu Zn Au Ag % %
Classification Areas Tonnes (t/m3) % % (g/t) (g/t) Fe Cueq(i)
Total All
Measured areas 85,900 3.52 1.75 7.01 0.11 25.7 6.04 5.46
Total All
Indicated areas 236,400 3.52 1.84 5.63 0.30 45.2 6.58 5.05
Measured+ All
Indicated areas 322,400 3.52 1.82 6.00 0.25 40.0 6.44 5.16
Total All
Inferred areas 274,600 3.52 2.04 6.36 0.35 50.5 6.73 5.67

Since mining and processing began in 2005, the Company has processed over 190,000 tonnes of mineralized rock from the Upper Skarn (US) at its Malpaso mill. Table 1 shows that the total measured and indicated resource of the Upper Skarn, based on work to date, is about 320,000 tonnes and the inferred resource is about 275,000 tonnes. Provided that the inferred resource is confirmed, at the current capacity of the Malpaso-Mill, this would provide five years of feed for the mill while additional resources may be discovered and developed.

In addition to the resources of the Upper Skarn, inferred resources have been calculated for the Lower Skarn in the El Gallo area. Table 2 shows the inferred tonnage at various %Cu-eq cut-off grades:

Table 2
Resources of the Lower Skarn of the Bolivar Project
The cutoff grade applied in the Lower Skarn (%Cueq) is variable
on the SG % % Au Ag % %
% Cueq Classification Tonnes (t/m3) Cu Zn (g/t) (g/t) Fe Cueq(i)
0.00 Inferred 22,230,000 3.27 0.32 0.08 0.09 6.4 6.58 0.43
0.25 Inferred 13,280,000 3.27 0.49 0.11 0.13 9.7 9.43 0.65
0.50 Inferred 6,114,000 3.27 0.76 0.13 0.20 15.1 12.50 0.99
0.75 Inferred 3,248,000 3.27 1.04 0.14 0.27 20.5 15.26 1.34
1.00 Inferred 2,320,000 3.27 1.19 0.15 0.31 23.2 16.79 1.52
1.25 Inferred 1,438,000 3.27 1.39 0.17 0.38 26.4 18.43 1.77
1.50 Inferred 936,000 3.27 1.57 0.17 0.45 29.3 19.22 1.99

It is important to note that the Lower Skarn has only been drilled within an area that encompasses less than 5% of the known extent of the Lower Skarn horizon. Considerable drilling remains to be done to test the horizon, and the Company continues to use the Yerington, Nevada, iron-copper skarns as its exploration model, for example the Northwest deposit of 3.0 mt @ 3.45% Cu and "minor" Fe, the East deposit of 7.1 mt @ 3.36% Cu and 27% Fe, the 2 deposit of 2.0 mt @ 3.60% Cu and 28% Fe, and the Pumpkin Hollow (core) of 29.0 mt @ 1.20% Cu and 40 % Fe. The mineralized zone within the resources of the Lower Skarn shown above is open laterally, and drilling directed at extending the known mineralized zone will continue.

Table 3 shows the combined inferred resource for the Upper and Lower Skarns at various %Cu-eq cut-off grades. Note that the left-most column shows the cut-off grade for the Lower Skarn on the left side and for the Upper Skarn on the right side of the column.

Note that this table shows only inferred resources, and does not include the Measured & Indicated Resources for the Upper Skarn shown in Table 1.

Table 3

Bolivar Project

Inferred resources of the Lower Skarn and Upper Skarn of the Bolivar Project
Cutoff on
the %Cueq SG % % Au Ag % %
LS - US Classification Tonnes (t/m3) Cu Zn (g/t) (g/t) Fe Cueq(i)
0.00 -2.50 Inferred 22,505,000 3.27 0.34 0.16 0.09 6.98 6.58 0.50
0.25 - 2.50 Inferred 13,555,000 3.27 0.52 0.23 0.14 10.55 9.38 0.75
0.50 -2.50 Inferred 6,389,000 3.28 0.82 0.39 0.21 16.60 12.25 1.19
0.75 - 2.50 Inferred 3,523,000 3.29 1.12 0.63 0.28 22.88 14.59 1.67
1.00 - 2.50 Inferred 2,595,000 3.30 1.28 0.81 0.31 26.08 15.72 1.96
1.25 - 2.50 Inferred 1,713,000 3.31 1.49 1.16 0.37 30.26 16.55 2.40


1. CIM Definitions were followed for the resource estimate.

2. A minimum width of 2 m was used for a mineralized zone.

3. Densities of mineralized rock are indicated in the tables.

Exploration Potential

On-going exploration by Dia Bras continues to extend known zones of copper, zinc, silver and gold mineralization along strike of the Rosario Trend as well as the Fernandez Trend, near the Bolivar Mine, as well as in other areas of the property, which encompass some 75 km2. Of particular interest are the newly defined targets of the La Montura - El Val trend that were recently drilled and have identified Upper and Lower Skarn type mineralization over a strike length of some 2 km, 2.5 km SW of the main Alta Ley mine area.

In the El Val area, drill hole DB07B209 intersected 2.0 metres at an average grade of 7.7% Zn in a Upper Skarn type environment within a broader mineralized intersection from 89 to 123 metres core length. Hole DB07B215, drilled some 500 metres to the NW in the Narizona area, also intersected a Cu-Zn mineralized zone, from 43 to 75 metres core length (assays pending) that shows Upper Skarn-type mineralization, and a second mineralized horizon, from 145 to 149 metres core length, with Lower Skarn type mineralization (assays pending). This corridor extends up to the La Montura showing where a drill hole done by Dia Bras in 2004 intersected 3 metres at 1.2% Cu, 5.4% Zn, 1 g/t Au and 147 g/t Ag in Upper Skarn type environment.

Geostat International is presently preparing a preliminary economic assessment in order to assess the economic potential of the Bolivar deposit. The complete preliminary economical assessment will be available under Dia Bras Exploration on the SEDAR website at www.sedar.com and on Dia Bras' website at www.diabras.com within 45 days of the present.

Dia Bras has already initiated systematic exploration drilling and has four surface and two underground drill rigs, testing all the mineralized structures continuously. Drill results will be issued as they become available.

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 that 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
    Thomas L. Robyn
    Executive Chairman
    Dia Bras Exploration
    Rejean Gosselin
    President & CEO
    Sun International Communications
    Nicole Blanchard
    Managing Partner