2014

Dia Bras more than triples proven and probable reserves at its Yauricocha Mine, Peru

VANCOUVER, Sept. 6, 2012 /PRNewswire/ - Dia Bras Exploration Inc. (TSX-V:DIB) (BVL: DIB) ("Dia Bras" or the "Company") is pleased to announce new reserve and resource estimates on its Yauricocha Property, Yauyos Province, Peru.  The estimates are as of January 1, 2012.  Resource modeling and mine planning work were performed by Yauricocha staff and audited by Gustavson Associates, LLC of Lakewood, Colorado ("Gustavson"). Traditional underground estimation methods are used for mineral resources at Yauricocha. These are polygonal methods used in the longitudinal section with careful geologic controls and factors which have been established and refined over the 40 years of continuous exploitation.

Press Release Highlights:

The estimated total Proven and Probable Reserves for the Yauricocha Mine are 4,162,940 tonnes @ 420.8 g/t AgEq at a cut-off grade of 83 g/t AgEq:

Average Grade: 119.7 g/t Ag, 2.81% Pb, 0.70% Cu, 2.57% Zn and 0.92 g/t Au.

As of May 25, 2011, Proven and Probable reserves were 1,140,030 tonnes.

The estimated total Measured and Indicated Resources, inclusive of reserves, are 4,181,390 tonnes @ 420.8 g/t AgEq at the same cut-off grade:

Average Grade: 121.8 g/t Ag, 2.91% Pb, 0.72% Cu,2.54% Zn and 0.93 g/t Au.

The estimated total Inferred Resources are 1,794,330 tonnes @ 276.4 g/t AgEq at the same cut-off grade:

Average Grade: 58.62 g/t Ag, 1.57% Pb, 0,64% Cu, 1.08% Zn and 1.10 g/t Au.

Daniel Tellechea, President and CEO of Dia Bras, commented: "These results demonstrate that the aggressive exploration done by the Company over the past year have paid off with this significant expansion of reserves.  We continue with our underground exploration drilling program in the Central Mine Area and expect to add significantly to the mine's reserves and resources over the coming year because we have significant geologic potential below the known mineralization."

Gustavson has carefully audited Corona's mineral resource estimation methodology and estimations, as well as the experience of the geologic team and their adherence to a standard methodology.  Gustavson considers that the work meets industry standard practice, and considers these estimates to be compliant with CIM definitions and NI43-101 standards.  Based on the overall audit of methods and work products, Gustavson is of the opinion that the quality of Corona estimates meets criteria for classification as a "mineral resource" under the CIM definitions.

Data used in estimation of resources and reserves consist of drift, sublevel, stope, raises and exploration drilling samples. The grades are assigned within the volume defined by the Yauricocha geologists, to provide the average grade of the block. The resulting average grade is adjusted for dilution and further adjusted by reconciliation with plant data from the previous two years.

Traditional underground estimation methods are used for mineral resources at Yauricocha. These are polygonal methods used in the longitudinal section with careful geologic controls and factors which have been established and refined over the 40 years of continuous exploitation.

The bodies are exploited using 8 mining methods depending on the material and rock mechanics characteristics of the resource.  Dilution factors vary between 10% for cut-and-fill mining and 25% for wet sub-level caving.  Yauricocha exploits three different types of mineral.  Each has a unique set of parameters for mine to mill reconciliation factors, which are presented in Table 1.

All of the factors used have been refined by Yauricocha through their production history and can be verified by examination of the resource estimates and mine production reports.

Table 1  Grade Adjustment for Mine-Mill Reconciliation

Polymetallic Bodies Copper Bodies Oxide Bodies
Ag -  8 % Ag -  6 % Ag -  10 %
Pb -  6 % Pb -  0 % Pb -  10 %
Cu -  10 % Cu -  6 % Cu -  5 %
Zn -  8 % Zn -  0 % Zn -  5 %

Gustavson has audited Yauricocha's work and accepts responsibility for the resource estimate.

Yauricocha Reserve and Resource Estimates

The estimated mineral resources are reported at an average cut-off grade of 83 gpt expressed in terms of silver equivalent grade (AgEq).  This is the grade reported by Yauricocha and the result of the estimates and adjustment factors previously discussed.

AgEq= (Ag *Pag* Rag/31.1035)+(Pb*Ppb*Rpb*22.05)+(Cu*Pcu*Rcu*22.05)+(Zn*Pzn*Rzn*22.05)

(Pag* Rag)

Where the symbols represent

Metal Symbol Grade Units Price Price Symbol Recovery Symbol
Silver Ag g/t 26.28 $/tOz Pag Rag
Copper Cu % 3.491 $/lb Ppb Rpb
Lead Pb % 0.9988 $/lb Pcu Rcu
Zinc Zn % 0.9531 $/lb Pzn Rzn

Recovery Copper Bodies Lead Oxides Lead Sulfides Polymetallics
Rag 65.50% 29.50% 12.50% 66.10%
Rpb 61.72% 58.09% 6.85% 32.80%
Rcu 90.09% 11.44% 20.50% 55.92%
Rzn 85.95% 6.71% 11.34% 87.92%

*Gold is low grade and erratic and not included in the cutoff estimation.  (As of March 25, 2011, the average gold grade was 0.56 g/t in 1,140,030 tonnes of Proven and Probable Reserves.)

The Yauricocha mineral resource estimation for January 1, 2012 is presented in Tables 2 through 5.  Mineral resources at Yauricocha are inclusive of mineral reserves.

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

Table 2 - Yauricocha Measured Mineral Resources

ORE TYPES MEASURED RESOURCES METAL CONTENT
m-ton AgEq (gpt) Ag(gpt) Pb(%) Cu(%) Zn(%) Au(gpt) Ag(kg) Ag(oz*106) Pb(m-ton) Cu(m-ton) Zn(m-ton) Au(g)
 Polymetallic Ores 1,026,840 374.66 85.02 1.86 0.70 4.33 0.47 87,302 2.807 19,099 7,188 44,462 478,487
 Copper Ores 117,130 376.97 86.29 0.38 2.08 1.21 0.40 10,107 0.325 445 2,436 1,417 46,852
 Oxide Ores 475,560 776.66 323.11 8.23 0.23 0.98 2.36 153,658 4.940 39,139 1,094 4,660 1,122,322
TOTALS 1,619,530 492.87 155.02 3.62 0.66 3.12 1.02 251,067 8.072 58,683 10,718 50,540 1,647,661

Table 3 - Yauricocha Indicated Mineral Resources

ORE TYPES INDICATED RESOURCES METAL CONTENT
m-ton AgEq (gpt) Ag(gpt) Pb(%) Cu(%) Zn(%) Au(gpt) Ag(kg) Ag(oz*106) Pb(m-ton) Cu(m-ton) Zn(m-ton) Au(g)
 Polymetallic Ores 1,717,320 261.37 46.16 0.97 0.61 2.87 0.55 79,278 2.549 16,605 10,442 49,334 950,994
 Copper Ores 296,180 382.44 66.15 0.34 2.08 0.83 0.99 19,592 0.630 1,007 6,154 2,463 292,083
 Oxide Ores 489,860 758.79 318.53 9.23 0.23 0.46 1.95 156,035 5.017 45,214 1,105 2,253 955,227
 Copper Oxide Ores 58,500 468.57 19.25 0.54 3.19 2.49 0.40 1,126 0.036 314 1,866 1,454 23,384
TOTALS 2,561,860 375.21 99.94 2.46 0.76 2.17 0.87 256,031 8.231 63,139 19,566 55,504 2,221,688

Table 4 - Yauricocha Measured + Indicated Mineral Resources

ORE TYPES MEASURED + INDICATED RESOURCES METAL CONTENT
m-ton AgEq (gpt) Ag(gpt) Pb(%) Cu(%) Zn(%) Au(gpt) Ag(kg) Ag(oz*106) Pb(m-ton) Cu(m-ton) Zn(m-ton) Au(g)
 Polymetallic Ores 2,744,160 303.76 60.70 1.30 0.64 3.42 0.52 166,580 5.356 35,704 17,629 93,796 1,429,482
 Copper Ores 413,310 380.89 71.86 0.35 2.08 0.94 0.82 29,699 0.955 1,452 8,591 3,880 338,935
 Oxide Ores 965,420 767.59 320.79 8.74 0.23 0.72 2.15 309,693 9.957 84,353 2,198 6,914 2,077,549
 Copper Oxide Ores 58,500 468.57 19.25 0.54 3.19 2.49 0.40 1,126 0.036 314 1,866 1,454 23,384
TOTALS 4,181,390 420.78 121.28 2.91 0.72 2.54 0.93 507,098 16.303 121,822 30,284 106,044 3,869,349

Table 5 - Yauricocha Inferred Mineral Resources

ORE TYPES INFERRED RESOURCES METAL CONTENT
m-ton AgEq (gpt) Ag(gpt) Pb(%) Cu(%) Zn(%) Au(gpt) Ag(kg) Ag(oz*106) Pb(m-ton) Cu(m-ton) Zn(m-ton) Au(g)
 Polymetallic Ores 444,740 302.92 64.91 1.96 0.44 3.83 0.28 28,868 0.928 8,702 1,937 17,047 126,152
 Copper Ores 624,880 231.02 27.40 0.10 1.46 0.32 0.59 17,122 0.550 640 9,126 2,013 369,336
 Oxide Ores 204,710 698.43 288.33 9.17 0.17 0.11 1.77 59,024 1.898 18,778 342 233 361,927
 High Grade Gold Ores (Adrico) 520,000 142.05 0.34 0.00 0.00 0.00 2.16 177 0.006 0 0 0 1,123,200
TOTALS 1,794,330 276.38 58.62 1.57 0.64 1.08 1.10 105,191 3.382 28,119 11,405 19,294 1,980,615

Gustavson has audited the detailed mine planning performed by the Yauricocha staff and has determined that the quality and level of detail of the work is sufficient to support a "mineral reserve" under the CIM definitions.  In addition to the dilution and reconciliation factors applied to resources, a mine recovery factor, differentiated by mining method is applied to the reserves.  This factor varies from 90% for sub level caving to 70% for sub level caving in the presence of water.

The estimated mineral reserves are reported at an average cut-off grade of 83 gpt expressed in terms of silver equivalent grade (AgEq).  This is the grade reported by Yauricocha and the result of the estimates and adjustment factors previously discussed.

The proven and probable reserves are inclusive of the measured and indicated resources.  Tables 6 through 8 summarize the Yauricocha mineral reserves.  The mineral reserve estimation for January 1, 2012 is presented in Tables 6, 7 and 8.

Table 6  Yauricocha Proven Mineral Reserves 

ZONE PROVEN RESERVES
m-ton AgEq (gpt) Ag(gpt) Pb(%) Cu(%) Zn(%) Au(gpt)
CACHI CACHI & MINA CENTRAL 1,013,350 534.04 189.40 4.46 0.52 2.40 1.29
 Polymetallic Ores 517,350 353.69 87.40 1.83 0.64 3.98 0.38
 Copper Ores 48,610 328.86 73.80 0.18 1.96 0.62 0.41
 Oxide - Mascota Lower Levels 428,730 755.77 317.00 7.75 0.23 0.66 2.50
 High Grade Oxides 18,660 974.27 385.40 13.04 0.23 3.41 1.12
MINA IPILLO (Polymetallic) 0            
MINA VICTORIA (Copper Ore) 0            
TOTALS 1,013,350 534.04 189.40 4.46 0.52 2.40 1.29

Table 7 Yauricocha Probable Mineral Reserves

ZONE PROBABLE RESERVES
m-ton AgEq (gpt) Ag(gpt) Pb(%) Cu(%) Zn(%) Au(gpt)
CACHI CACHI & MINA CENTRAL 3,024,310 373.24 97.10 2.33 0.73 2.60 0.80
 Polymetallic Ores 2,295,920 287.29 52.00 1.10 0.68 3.21 0.53
 Copper Ores 254,970 379.80 63.90 0.22 2.06 0.86 1.05
 Oxide - Mascota Lower Levels 437,440 774.22 332.20 9.29 0.24 0.17 2.06
 High Grade Oxides 35,980 935.67 348.00 10.62 0.24 6.07 0.96
MINA IPILLO (Polymetallic) 65,830 503.88 119.50 1.14 1.06 5.45 1.15
MINA VICTORIA (Copper Ore) 59,450 367.79 80.60 0.83 1.98 0.80 0.49
TOTALS 3,149,590 375.86 97.20 2.27 0.76 2.63 0.80

Table 8 Yauricocha Proven + Probable Mineral Reserves

ZONE TOTAL PROVEN + PROBABLE RESERVES
m-ton AgEq (gpt) Ag(gpt) Pb(%) Cu(%) Zn(%) Au(gpt)
CACHI CACHI & MINA CENTRAL 4,037,660 413.79 120.20 2.86 0.67 2.55 0.93
 Polymetallic Ores 2,813,270 299.84 58.50 1.24 0.67 3.35 0.51
 Copper Ores 303,580 371.25 65.50 0.21 2.04 0.82 0.95
 Oxide - Mascota Lower Levels 866,170 765.02 324.70 8.53 0.23 0.42 2.28
 High Grade Oxides 54,640 949.65 360.80 11.45 0.24 5.16 1.02
MINA IPILLO (Polymetallic) 65,830 503.88 119.50 1.14 1.06 5.45 1.15
MINA VICTORIA (Copper Ore) 59,450 367.79 80.60 0.83 1.98 0.80 0.49
TOTALS 4,162,940 414.56 119.70 2.81 0.70 2.57 0.92

*Reserves from the Ipillo and Victoria Mines are conditional to negotiations with the local community and permit from the authority.

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, EIT, SME-RM of Gustavson 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.




Custom Packages

Browse our custom packages or build your own to meet your unique communications needs.

Start today.

 

PR Newswire Membership

Fill out a PR Newswire membership form or contact us at (888) 776-0942.

Learn about PR Newswire services

Request more information about PR Newswire products and services or call us at (888) 776-0942.