 | |
Banderas is a classic low sulphidation epithermal gold-silver vein system located in eastern Guatemala. Sampling of banded quartz veins returned values up to 28 g/t Au and 553 g/t Ag in trenches. A two phase program of core drilling, totaling 2545m, was completed in early 2004. Best results from core included 18g/t Au over 1.5m and 332 g/t Ag over 1.6m. Radius joint ventured Banderas to Glamis Gold in late 2004 but Glamis recently withdrew from the joint venture after drilling on the project.
Location and Access
Banderas is located about 3 hours drive from Guatemala City, close to the town of Chuiquimula. Infrastructure is excellent and the project is just a 45 minute drive up into the hills surrounding Chiquimula. The project is accessible by dirt road followed by a short walk (click here for location map).
History
Banderas was discovered in early 2002 during follow up of regional stream sediment sampling anomalies. An 8km2 area of altered volcanics was discovered and a number of outcrops of silicified, pyritic breccias were found associated with a large (ca. 15km2) gold in soil anomaly.
The project was mapped in detail, some 2080 soil and 1500 rock samples were collected and 24 hand trenches excavated. Subsequently work included two phases program of core drilling, totaling 2545m, completed in early 2004. The hand trenching returned values up to 28 g/t Au and 553 g/t Ag from banded veining. Best results from drilling included 18g/t Au over 1.5m and 332 g/t Ag over 1.6m.
In November 2004, Radius signed an agreement with Glamis Gold that gave Glamis the right to acquire a 51% interest in the properties by spending US$4-million over a four year period. Glamis completed a number of drill holes on the project before withdrawing from the joint venture mid-2006. Radius now controls 100% of the project.
Geology
The Banderas property is underlain by Tertiary volcanics consisting of andesitic flows and tuffs, overlain by rhyolitic flows and tuffs, which may form part of a larger volcanic dome field. Amygdaloidal textures are seen in andesite flows, and classic flow banding is evident in rhyolitic flow units.
Structurally, the area is dominated by 140° to 160° trending normal faults, interpreted to represent extensional features related to formation of the Ipala Graben. This is same structural environment as at Holly, located 9km to the NW. Several rhyolitic flow domes occur along this 140-160° trend at Banderas, coincident with the mineralized vein zones, which may have been localized by the same structures.
Vein Zones
Mineralization at Banderas occurs in two parallel NNW trending zones, the Zapote and Lomas trends, about 1500m apart. Exploration to date has largely focused on the eastern trend, where two main structures -the Pyramid Hill and M28 zones- have been identified. These are roughly parallel, striking about 140-160°, and each consist of multiple veins.
The Pyramid Hill zone consists of at least 3 veins which dip sub-vertically, one of which has been traced over 1800m in strike length. The M28 zone (so named for the 28 g/t Au discovery sample) consists of at least 2 veins, which dip shallowly to the west near surface and steepen at depth. This zone has been traced over 800m strike length.
The veins are generally 2-5m thick, and are commonly situated within a stockwork vein zone up to 50m thick, comprised of cm scale quartz veinlets. Silicified pyrite rich hydrothermal breccias are also associated with the main veins, typically occurring in the hangingwall. Grades higher than 1 g/t Au are generally restricted to the main veins, whereas stockwork and breccias zones typically run below 1 g/t Au.
Best assays from trenches in the M28 zone included 30 g/t Au over 1.5m, and 41 g/t over 1m. Best assays from trenches in the Pyramid Hill zone included 10.3 g/t Au over 2.1m and 4.3 g/t Au over 2.7m. The full trench results can be viewed by following this link.
Mineralization and Alteration
Mineralization consists mainly of pyrite, argentite and electrum, hosted by multiphase, banded silica-adularia veins and hydrothermal breccias. Quartz after calcite textures are ubiquitous and up to 15% adularia is locally present. Finely banded chalcedonic quartz with black sulphidic "ginguro" bands is usually associated with the highest grades.
Argillic (clay) alteration is widespread and affects volcanic rocks over an area of at least 12 sq. km. Illite and kaolinite are most closely associated with mineralization, which is interpreted as being low temperature, and near the top of the gold deposition zone, with good potential for mineralization at depth.
Drilling
A total of 2545m of core drilling was completed in 22 holes at Banderas in 2 phases conducted during late 2003 and early 2004. Phase 1 focused on the M28 trend with 10 holes, and Phase 2 concentrated on the Pyramid Hill trend with 12 holes.
Best assays included 21.5 g/t Au (+147 g/t Ag) over 0.6m in hole BDD-003, and 18.7 g/t Au (+64 g/t Ag) over 1.5m in hole BDD-008. The highest silver assay was 332 g/t (+8.5 g/t Au) over 1.6m in hole BDD-014. Silver results typically add 1-2 g/t Au equivalency.
The M28 zone was drilled on 3 sections along 350m strike length, and up to 180m down dip. Drilling confirmed a shallow western dip, and good continuity down dip. The Pyramid Hill zone was drilled on 4 sections along 1500m of strike length to 130m down dip. Drilling confirmed a sub-vertical dip and good continuity along strike.
Table 1. Banderas Trench results
Table 2. Banderas Phase 1 Drill results
In late 2004 through late 2005, Glamis completed a number of small drill programs at Banderas. The results of Glamis' drilling included hole BRC-04-024, drilled on the RAT zone, which intersected 9.5m @ 12.4g/t Au + 95g/t Ag from 165.0m to 174.5m downhole, including 3.0m @ 36.5 g/t Au and 274 g/t Ag from 167.0 to 170.0m associated with massive or semi-massive quartz veining within a moderately to shallowly, southwest-dipping zone. All other intercepts returned less than 1.5 g/t Au. A drill collar map showing the locations of all holes drilled by Glamis is available below. The intercept is approximately 300m southeast along strike from PilaGold's drilling on the M28 zone which returned a best intersection of 2.7m @ 6.8 g/t Au + 95 g/t Ag.
Based on the results of their program, Glamis withdrew from the JV in mid-2006 and returned the project to Radius.
Conclusions
Drilling at Banderas has confirmed a robust epithermal vein system with good strike and down dip continuity. Veins have been exposed over 300m vertical relief and traced over 2000m in strike length, and the system is open along strike to the north and south.
The Banderas property has been merged with the Holly land package, forming a highly prospective area of at least 7 x 13 km. The intervening area contains strike extensions of key faults and graben features that trend between the 2 prospects, and has seen 1st pass prospecting but no significant follow up.
At Banderas, 2545m of diamond drilling has been completed in 22 holes, and additional drilling completed by Galmis, returning assays up to 18.7 g/t Au over 1.5m and silver values up to 332 g/t from core and 3.0m @ 36.5 g/t Au and 274 g/t Ag in RC. Trenching has resulted in values up to 41 g/t Au over 1m, and float samples have returned values as high as 374 g/t Au and 3524 g/t Ag. The source of this high grade float has yet to be identified and Radius' technical team believe that additional work is warranted.
Planned Work
Glamis have now withdrawn from the Banderas joint venture and returned the project to Radius. Radius is assessing how to proceed with the project.
Click Here to View Banderas Photo Gallery
Maps
| |
|
){kind=link}
){kind=link}
){kind=link}
){kind=link}