Dia Bras increases measured and indicated resources over 12-fold to 15.4 million tonnes at its Bolivar Property, Chihuahua State, Mexico

Aug 30, 2012, 06:00 ET from Dia Bras Exploration Inc.

TSX Venture Exchange - DIB
Bolsa de Valores de Lima - DIB

TORONTO, Aug. 30, 2012 /PRNewswire/ - Dia Bras Exploration Inc. (TSX-V:DIB) (BVL: DIB) ("Dia Bras" or the "Company") is pleased to announce a new resource estimate on its Bolivar Property, Chihuahua State, Mexico.  These resources are in four areas of the Bolivar operating mine: 1) Alta Ley; 2) Increíble; 3) Ell Gallo Superior; and, 4) El Gallo Inferior.  This resource estimate was prepared by Gustavson Associates, LLC ("Gustavson") of Lakewood, Colorado.

Press Release Highlights:

  • The total estimated Measured and Indicated Resources for the Bolivar Property are:
    • 15,404,000 tonnes averaging 19.4 g/t Ag, 0.79% Cu and 1.01% Zn at a mill feed cut-off grade of 0.66% CuEq.
  • Total estimated Inferred Resources are:
    • 6,164,000 tonnes averaging 18.1 g/t Ag, 0.73% Cu and 0.93% Zn at the same cut-off.
  • For the first seven months of 2012, the average mill feed grade to the Piedras Verdes mill is 2.02% CuEq.
  • Drilling continues with the objective of expanding the resources of the property, especially in the area between El Gallo and Increíble.
  • The possibility of recovering magnetite from the Lower Skarn is being evaluated.

Daniel Tellechea, President and CEO of Dia Bras, commented: "These results demonstrate that the many years of exploration and pilot mining done by the Company have paid off and our investment in the new Piedras Verdes mill is very well supported. We have sufficient tonnes to expand the mill to 2,000 tonnes per day capacity. The Company also plans to initiate a Preliminary Economic Analysis with the objective of moving some resources to reserves."

Methods of Estimation

The major structures and mineralized zones were evaluated by Gustavson using two different estimation methods.

1) The skarn mineralization within the El Gallo zone was modeled as a stratigraphic unit with pockets of mineralization. The two zones modeled were the upper and lower skarns. These units appear to be long, continuous tabular bodies that grade from proximal to distal with mineralization changing from copper dominant to zinc dominant. Both of these zones were estimated using an ordinary kriging algorithm. All drill holes that intersected the modeled horizons were coded for estimation. If a sample was not assayed it was replaced with a value equal to half of the detection limit for the analysis. This prevented the spreading of economic minerals into areas without assays. It was the assumption of Gustavson that areas that have not been assayed are not mineralized and warrant the use of a below detection limit value.

2) The mineralization within the Alta Ley and Increίble zones is very complex. To overcome the complexities of the mineralization and represent the multiple directions of mineralization Gustavson chose to use a Multiple Indicator Kriging (MIK) algorithm. This algorithm allows for the estimation of multiple grade cutoffs as probabilities of an entire block. The probabilities of a block exceeding a particular cutoff are then used to recreate the weighted average block grade. Again Gustavson replaced missing sample intervals with a value equal to half of the detection limit for the analysis.

Bolivar Property Resource Estimate

The following tables show the Bolivar Property Measured, Indicated, and Inferred Resources at various cut-off grades.  The 0.66% copper equivalent cut-off grade was selected by Gustavson as a base case.

Total Bolivar Measured Resources
Cutoff Tonne Copper Equivalent Silver Copper Zinc
%CuEq (x 1000) % lbs. (x 1000) gpt oz. (x 1000) % lbs. (x 1000) % lbs. (x 1000)
0.85% 6,394 1.59% 223,658 26.4 5,431 1.00% 140,780 1.20% 169,658
0.75% 7,584 1.46% 244,605 24.2 5,891 0.93% 155,501 1.08% 181,048
0.66% 8,847 1.35% 264,205 22.3 6,333 0.87% 169,423 0.98% 190,851
0.55% 10,800 1.22% 290,252 19.9 6,917 0.79% 188,163 0.85% 203,091
0.45% 12,927 1.10% 313,629 17.8 7,410 0.72% 204,787 0.76% 215,594
Total Bolivar Indicated Resources
Cutoff Tonne Copper Equivalent Silver Copper Zinc
%CuEq (x 1000) % lbs. (x 1000) gpt oz. (x 1000) % lbs. (x 1000) % lbs. (x 1000)
0.85% 3,898 1.41% 121,079 19.2 2,401 0.81% 69,412 1.26% 108,330
0.75% 5,075 1.27% 141,788 17.2 2,806 0.74% 82,669 1.15% 128,432
0.66% 6,557 1.14% 164,706 15.6 3,285 0.67% 97,316 1.05% 151,389
0.55% 9,190 0.99% 199,624 13.5 4,003 0.59% 120,449 0.89% 179,440
0.45% 12,611 0.85% 237,264 11.9 4,824 0.52% 145,938 0.75% 207,845
Total Bolivar Measured & Indicated Resources
Cutoff Tonne Copper Equivalent Silver Copper Zinc
%CuEq (x 1000) % lbs. (x 1000) gpt oz. (x 1000) % lbs. (x 1000) % lbs. (x 1000)
0.85% 10,292 1.52% 344,738 23.7 7,832 0.93% 210,192 1.23% 277,987
0.75% 12,659 1.38% 386,393 21.4 8,697 0.85% 238,170 1.11% 309,480
0.66% 15,404 1.26% 428,912 19.4 9,619 0.79% 266,739 1.01% 342,240
0.55% 19,990 1.11% 489,876 17.0 10,920 0.70% 308,613 0.87% 382,530
0.45% 25,538 0.98% 550,893 14.9 12,234 0.62% 350,725 0.75% 423,440
Total Bolivar Inferred Resources
Cutoff Tonne Copper Equivalent Silver Copper Zinc
%CuEq (x 1000) % lbs. (x 1000) gpt oz. (x 1000) % lbs. (x 1000) % lbs. (x 1000)
0.85% 3,824 1.42% 119,675 22.2 2,729 0.88% 74,558 1.17% 69,448
0.75% 5,035 1.27% 140,846 19.9 3,222 0.79% 87,390 1.05% 75,437
0.66% 6,164 1.17% 158,434 18.1 3,590 0.73% 99,796 0.93% 106,444
0.55% 7,772 1.05% 179,615 16.1 4,033 0.67% 114,431 0.81% 129,273
0.45% 9,120 0.97% 194,470 15.1 4,413 0.62% 124,009 0.74% 144,754
*     CuEq(%) = Cu % +
Zn % * Zn price * Zn recovery
Cu price * Cu recovery
Ag gpt * Ag Price * Ag recovery
22.0462 * Cu price * 31.10348 * Cu recovery

Quality and grade are estimates and are rounded to reflect the fact that the resource estimate is an approximation.

Mineral Resources are not Mineral Reserves and do not demonstrate economic viability.  There is no certainty that all or any part of the Mineral Resource will be converted to Mineral Reserves.

The property is currently in full commercial production. Mining started at Bolivar as a pilot project to evaluate the deposit's technical and economic viability.  This has gradually expanded to the current commercial production status of over 1,000 tpd, which represents a three-fold increase over our 2011 capacity.  No feasibility study has been completed, however, which may lead to increased technical and economic risks.

The Company is continuing an aggressive drilling program between the El Gallo and Increíble deposits with the objective of expanding the resources of both deposits as well as discovering high-grade copper deposits at the intersection of the Upper and Lower Skarn horizons with the Increíble breccia pipe.

During the period January through end-July, the Piedras Verdes mill processed 170,609 tonnes averaging 19.0 g/t silver, 1.15% copper, and 2.54% zinc, which equates to a CuEq grade of 2.02%.

The Lower Skarn contains abundant magnetite, ranging from 10 to 30% by volume with occasional lenses and pods of massive magnetite.  The Company is evaluating the feasibility of recovering the magnetite as a by-product through metallurgical testing and consideration of the additional recovery equipment required.

Method of Analysis

Samples were prepared at the ALS 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 analyzed by Induction Coupled Plasma (ICP) at ALS Chemex.

The technical content of this news release has been approved by Thomas L. Robyn, Ph.D., CPG, RPG, a Qualified Person as defined in NI 43-101 and Head of Exploration for Dia Bras Exploration, Inc.  Zachery Black of Gustavson Associates was responsible for the resource estimate.  Mr. Black is a Qualified Person as defined in NI 43-101 and an Associate Senior Resource Geologist.

About Dia Bras

Dia Bras Exploration is a Canadian mining company focused on precious and base metals in Chihuahua State, other areas of northern Mexico, and at its Yauricocha silver-lead-zinc-copper-gold mine in Peru. The Company is accelerating exploration at the Yauricocha property as well as pursuing the development and exploration of its most advanced Mexican assets - the Bolivar Property (copper‐zinc‐silver) and the Cusi Property (silver) and is exploring in Mexico several precious metal targets such as La Sidra gold project at the Bolivar Property, the Las Coloradas silver project at Melchor Ocampo (Zacatecas State), the Bacerac silver project (Sonora State), and the La Verde gold project at the Batopilas Property (Chihuahua State).  Dia Bras is also exploring base metal projects in Mexico such as the Corralitos intrusion-hosted molybdenum deposit (Chihuahua State).

The Company's shares trade on the Bolsa de Valores de Lima and TSX Venture Exchange under the symbol "DIB".

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 news 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.

SOURCE Dia Bras Exploration Inc.