Dia Bras Exploration Inc.

Dia Bras Exploration Inc.

April 29, 2010 13:46 ET

Dia Bras Continues Drilling High-Grade Silver Mineralization at Cusi

MONTREAL, QUEBEC--(Marketwire - April 29, 2010) - Dia Bras Exploration Inc. (TSX VENTURE:DIB) is pleased to announce further results of exploration drilling and underground sampling at the Santa Eduwiges and Promontorio mines http://www.diabras.com/en/newscenter/2010/Cusi_Silver.pdf of Dia Bras' Cusi property, in Chihuahua State, Mexico, which are being conducted in support of the pilot-mining that recommenced in early October, 2009.  The objective of the drilling of the San Antonio and San Antonio A veins of the Santa Eduwiges mine vein system is to identify blocks that will be pilot-mined during 2010 (San Antonio vein; see attached long section http://www.diabras.com/en/newscenter/2010/Long_SanAntonio.pdf).  Drilling and sampling at the Promontorio mine (El Gallo vein; see attached long section http://www.diabras.com/en/newscenter/2010/Long_El_Gallo.pdf) is designed to support development of a mine plan for 2011, when pilot-mining is scheduled to begin at this mine and its output added to that of Santa Eduwiges.

The Cusi property contains 12 historical mines, and Dia Bras is focusing its efforts on two of them at the present time, the Santa Eduwiges and Promontorio mines.  A third historical mine, San Juan, will be drill tested during June for possible re-opening and pilot-mining during late 2010.   

Both the Santa Eduwiges and Promontorio mines contain clusters of veins, each of which has a different name.  The mines and veins are:   

  • Santa Eduwiges mine (or area) contains the veins Santa Eduwiges, Santa Marina, Santa Marina Alto, San Antonio, San Antonio A, Tascate, Mexicana, San Bartolo, Moctezuma and Soledad. 

  • Promontorio mine (or area) contains the veins El Gallo, El Gallo Back, Promontorio, the "alphabet" veins C, H, J, K & L (subsurface), Transversal (subsurface), Veta del Contacto, Minerva, San Nicolas and San Ignacio. 

  • San Juan mine contains only the San Juan vein.

Pilot-mining Development

Dia Bras' objective is to continue pilot-mining the multiple veins in the Santa Eduwiges mine area and to develop the Promontorio mine and San Juan mines in a sequenced fashion so that production is gradually increased. Silver-mineralized rock produced from these mines, as well as other mines as they are developed, will be shipped to the Corporation's mill at Malpaso and processed. The objective is to have pilot-mining production of 400-500 tonnes per day within 2-3 years.

For this reason, Management decided not to remove one of the processing circuits at the Malpaso Mill to install it in the new mill being constructed at the Bolivar Mine. Considering that production from the Cusi mines will be significant in a relatively short time, Management decided it was best to leave the Malpaso Mill as is and concentrate on raising production from Cusi so that the mill will be operating at capacity strictly with Cusi rock.

Table 1. Cusi project - Latest assay results from drill samples:

Hole ID From (m) To
Interval (m) Estimated
True Width (m)
Ag (g/t) Pb (%) Zn (%) Vein
DC10B274 160.70 162.10 1.40 1.01 290 0.74 1.18 San Antonio
DC10B277 78.85 79.30 0.45 0.30 255 0.02 0.01 El Gallo
DC10B278 59.80 61.30 1.50 0.90 298 0.12 0.13 Transversal
DC10B279 107.20 107.80 0.60 0.45 418 0.19 1.34 Transversal
  124.60 125.50 0.90 0.75 941 0.12 0.02 El Gallo
  126.90 129.00 2.10 1.50 129 0.30 0.09 FW** El Gallo
DC10B280 31.15 32.90 1.75 1.30 406 0.42 0.18 San Antonio*
  32.90 34.20 1.30 1.00 625 0.27 0.05 FW S. Antonio
Includes 33.60 34.20 0.60 0.45 930 0.29 0.02 FW S. Antonio
DC10B281 84.90 86.20 1.30 1.10 495 0.05 0.08 El Gallo
DC10B282 44.50 46.40 1.90 1.20 257 0.14 0.08 FW S. Antonio
All assays from ALS Chemex                
* Possibly backfill                
** FW = footwall                

Drilling in the Santa Eduwiges mine area continues with the objective of filling the gap of information above elevation 1970 in the Santa Marina Alto vein and the upper levels of the San Bartolo. Hole DC10B280 was completed over the Santa Marina stope and cut a vein that can be correlated with the San Bartolo vein, which was intercepted after crossing the San Antonio vein stope. Another narrow zone hosting quartz veinlets with weak-to-moderate sulphide association was also intercepted over the hanging wall of the Santa Marina stope. Results of the sampling demonstrate high-grade mineralization in the foot wall of the stope. One section of the core appears to be backfill, with over 400 g/t Ag (see Table 1. above). The second hole, which is DC10B282 crossed the San Antonio stope and a mineralized zone with over 250 g/t Ag in the foot wall. A hole in progress is designed to cut projections of the San Bartolo, Santa Marina Alto and Santa Marina veins. An additional 12-15 surface drill holes and 5-6 underground holes are planned at Santa Eduwiges.

Drilling at El Gallo vein is in progress with two rigs. To date, a total of 15 holes has been completed in this area. These holes cut the El Gallo vein, and one of the last holes intersected a wider mineralized zone that does not correspond with the known veins. This zone was cut by hole DB10B286 and contains sphalerite and chalcopyrite mineralization, with a narrower section where silver mineralization is present; sampling of this core is in progress. This drilling has added volume to the mineralized volume of rock with an average of 331 g/t Ag. An additional 12-15 surface drill holes and 5-6 underground holes are planned at El Gallo.

Table 2 below shows results of assays from underground sampling of the El Gallo vein of the Promontorio mine. Samples were collected from the backs of the drift on Level 6 and from the access ramp at two metre intervals along the indicated length of samples. The Blocks of mineralized rock indicated in the table are shown on the accompanying section of El Gallo.

Table 2. Promontorio mine - El Gallo vein – Underground Sample Assays 

Block No. Length
Avg. Width (m) No. of Samples Weighted Avg. Ag g/t Weighted Avg. Pb % Weighted Avg. Zn %
1 21.5 0.98 11 204.4 0.06 0.20
2 30.0 1.41 28 353.7 0.17 0.39
3 16.0 0.53 9 293.2 0.11 0.56
4 13.0 1.13 16 737.6 0.18 0.99
5 17.0 1.50 23 955.2 0.26 0.39
6 23.0 1.35 12 451.2 0.41 0.59
7 17.5 1.27 13 341.0 0.35 0.71
All assays from ALS Chemex

Dewatering of the Promontorio mine has lowered water to the 7th level of the mine, and the Promontorio shaft is now being rehabilitated. The combination of drilling the El Gallo vein and shaft rehabilitation is part of the program to commence pilot-mining at Promontorio in early 2011.

Malpaso Mill Leach Circuit

Construction of the fourth vat has been completed and the vat loaded with mill tailings. Four vats are now operational, and each vat has a treatment capacity of 200 tonnes. Given the cycle time of six days, the four vats can process 800 tonnes of tailings per week, for a monthly treatment capacity of about 3,200 tonnes per month. A fifth vat will be constructed during May. 

The quality of doré bars has been improved, with recent bars assaying 90% silver. With the four operational vats, the Corporation expects to produce 20 bars of doré of 12 kg mass each per month, for a monthly production of about 216 kg of silver in doré.

43-101 Update

Dia Bras has commissioned Geostat (SGS Canada, Inc.) of Montreal, Quebec, to update the resource calculation for the Cusi project that Geostat completed in May, 2008 (please see Dia Bras' News Release of May 1, 2008). This calculation resulted in 2.12 million ounces of AgEq in the Measured plus Indicated categories and 14.6 million ounces of AgEq in the Inferred category for Santa Eduviges and Promontorio. 

Method of Analysis

Samples sent for analysis are 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 completed by Induction Coupled Plasma (ICP) at ALS Chemex.

Quality Control

The quality assurance-quality control (QA-QC) of Dia Bras has been described in detail in both RPA's NI 43-101 reports of December, 2006, at Cusi and October, 2005, for Bolivar.

The technical content of this news release has been approved by Thomas L. Robyn, Ph.D., RPG, CPG and Director of Dia Bras, a Qualified Person as defined in NI 43-101.

About Dia Bras

Dia Bras Exploration Inc. is a Canadian exploration mining corporation focused on precious and base metals in the State of Chihuahua and other areas of northern Mexico. The Corporation is committed to developing and adding value to its most advanced assets – the Bolivar copper-zinc project and the Cusi silver mining camp. The Corporation's shares trade 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.

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.

Contact Information

  • Dia Bras Exploration Inc.
    Daniel Tellechea
    President & CEO
    514-393-8875 ext. 241
    Dia Bras Exploration Inc.
    Karl J. Boltz
    Vice President, Corporate Development