 Copperstone Air Photo showing Target Zones & Development
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| | April 13, 2005
American Bonanza Drills 41.8 Grams per Tonne Gold Over 9.8 Metres-6 Metres True Thickness
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| | AMERICAN BONANZA GOLD CORP. (TSX:BZA) announces an update to the underground drilling program at its 100% owned high-grade Copperstone gold project in Arizona.
D-Zone Underground Core Drilling
Underground core drilling continues at the D-Zone. Objectives of this underground core drilling program are conversion of known historic indicated and inferred resources into measured resources and reserves, and mine planning. A total of 68 holes have been drilled with a combined length of 6,240 metres. Approximately 900 metres in 8 planned holes remain to be drilled in the program, which is about 90% complete and has a budget for the entire program of approximately US$1 million.
The most significant intercepts in the new assay results include a 9.8
metre zone grading 41.8 g/t gold in drill hole number DU5-64; a 3.0
metre zone grading 52.8 g/t gold in drill hole number DU5-65; a 3.0
metre zone grading 15.6 g/t gold in drill hole number DU5-66; and a 4.5
metre zone grading 35.7 g/t gold in drill hole number DU5-68.
As previously reported, these D-Zone drill intercepts are oblique to the mineralized Copperstone fault; true thicknesses of the D-Zone range up to 7 metres thick. True thickness of the DU5-64 intercept is 6 metres, with true thickness for the other intercepts announced here being generally between 2 and 3 metres or less.
The following table is a summary of assay results for this group of underground holes from the D-Zone drilling program:
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Hole ID From - To Intercept Gold Gold Copper
(ft) (m) (g/t) (opt) (%)
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DU5-62 9.0-14.0 1.2 15.0 0.437 0.7
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and 50.1-53.5 1.0 4.7 0.138 0.3
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DU5-63 2.0-5.0 1.0 3.7 0.107 0.4
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and 49.0-58.2 2.8 2.9 0.084 1.3
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DU5-64 4.0-8.5 1.4 32.5 0.949 TR
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and 133.0-165.0 9.8 41.8 1.219 TR
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including 152.5-158.0 1.7 90.1 2.627 TR
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and 227.4-228.9 0.5 6.7 0.194 TR
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DU5-65 0.0-18.1 5.5 4.8 0.140 TR
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and 334.0-344.0 3.0 52.8 1.541 TR
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DU5-66 78.0-88.0 3.0 15.6 0.456 0.5
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DU5-67 6.5-13.5 2.1 8.1 0.237 0.5
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and 61.1-66.3 1.6 7.6 0.223 TR
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DU5-68 4.0-18.6 4.5 35.7 1.041 0.3
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and 194.0-209.0 4.6 7.3 0.212 TR
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Surface drilling programs continue on the project with a total of 6
drilling rigs currently active.
Drill Hole Location Table:
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Hole ID T.D. (m) Northing Easting Elevation Azimuth Inc.
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DU5-62 41.0 1047547.5 332778.5 299.0 115 5
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DU5-63 34.7 1047547.5 332778.5 301.0 115 15
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DU5-64 89.9 1047547.5 332778.5 297.0 115 -15
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DU5-65 104.9 1047547.5 332778.5 296.0 115 -20
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DU5-66 45.3 1047547.5 332778.5 298.5 125 0
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DU5-67 36.3 1047547.5 332778.5 301.0 125 15
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DU5-68 106.9 1047547.5 332778.5 297.0 125 -15
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The D-Zone plan map for the drill holes is available on the Company's
website at:
http://www.americanbonanza.com/copperstone.asp
DETAILED INFORMATION
The Copperstone gold mineralization occurs within a package of sedimentary and volcanic rocks, in northwest striking, moderate to shallow dipping fault zones, principally the Copperstone Fault. Intensely sheared, altered and replaced rock characterizes the Copperstone Fault in the vicinity of the D-Zone. Alteration consisting of intense hematite and magnetite replacement, chloritization and silicification has been observed in the Copperstone Fault underground and is consistent with alteration visible in previous drilling and the current drilling from surface.
Gold mineralization is restricted to these fault zones, with little to no gold mineralization present in the wallrocks. Future exploration and development efforts will target these mineralized faults to follow up along strike and dip from the current results and previously drilled
mineralization.
Drilling services are being provided by international drilling contractors: Layne Christensen Company of Chandler, Arizona. The drilling and assaying are conducted under the supervision of Gregory French, CPG #10708, a Qualified Person as defined in Canadian National Instrument 43-101.
Underground core is NQ size, equaling 2 inches in diameter. The core samples are collected by Bonanza personnel at the drill for each drill hole. All of Bonanza's facilities are secure, inside the fenced compound. The core is transported to Bonanza's core processing facility on site at Copperstone by Bonanza personnel.
All core is logged for recovery and other geotechnical features, prior to being sawed lengthwise in half by Bonanza personnel. Individual core samples are selected on a geological basis to characterize the gold mineralization associated with various rock types, alteration types and structural horizons. Subsequent to sawing and sampling, the remaining half core is geologically logged and stored on site as reference samples.
Assay sample sizes average 5.3 pounds for the underground drilling. The core samples are bagged, labeled and tied at the Copperstone project site by Bonanza personnel. Geologic information is recorded on standardized sample description forms which included color, rock type, alteration, mineral species and abundance. Samples are stored in a secure facility at the Copperstone project site.
DATS Trucking, Inc. collects samples from the secure facility at Copperstone and transports the samples to representatives of American Assay Laboratories (AAL) in Sparks, Nevada. There, representatives of American Assay Laboratories (AAL) in Sparks, Nevada receive the samples and take custody of the samples. AAL is ISO / IEC 17025 certified and has successfully completed Canadian proficiency testing (CCRMP).
At the AAL laboratory, the core samples are dried, crushed to -10 mesh, pulverized to -150 mesh, split to 1,000 gram pulps, and fire assayed for gold two times using 2-assay ton fire assay charges with a gravimetric finish. Reported gold grades are the average of these two assays for each sample. A total of 402 core samples from the underground drilling were assayed in duplicate. There is good correlation between the duplicate assays. All samples greater than 0.100 opt, standards, and blanks are routinely submitted to additional labs for verification. An additional 28 standards were inserted for assay for the drill holes announced here.
Check assays are routinely submitted to BSI-Inspectorate, Sparks, NV 5-assay ton gold analysis. BSI-Inspectorate is ISO 9002 certified. Bonanza personnel deliver the samples to the check labs.
Additional information about Bonanza can be obtained at: www.americanbonanza.com
AMERICAN BONANZA GOLD CORP.
Brian Kirwin, President and Chief Executive Officer
This news release includes certain statements that may be deemed "forward-looking statements". All statements in this release, other than statements of historical facts, including the likelihood of commercial mining, possible future financings are forward-looking statements. Although the Company believes the expectations expressed in such forward-looking statements are based on reasonable assumptions, such statements are not guarantees of future performance and actual results or developments may differ materially from those in the forward-looking statements. Factors that could cause actual results to differ materially from those in forward-looking statements include unsuccessful exploration results, changes in metals prices, changes in the availability of funding for mineral exploration, unanticipated changes in key management personnel and general economic conditions. Mining is an inherently risky business. Accordingly the actual events may differ materially from those projected in the forward-looking statements. For more information on the Company and the risks and challenges of its business, investors should review the Company's annual Form on 20F filing with the United States Securities Commission and its home jurisdiction filings that are available at www.sedar.com
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CONTACT INFORMATION
FOR FURTHER INFORMATION PLEASE CONTACT:
American Bonanza Gold Corp.
Wayne Marsden
Toll Free: 1-877-366-4464
www.americanbonanza.com
or
American Bonanza Gold Corp.
Suite 1606-675 W. Hastings St.
Vancouver, BC V6B 1N2 |
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