Chiquimula, Guatemala — Zeroing in on a major regional crustal feature that offers a favourable setting for hosting large epithermal-type gold deposits, the geological team of
Radius has focused its attention on a Tertiary belt of volcanic rocks in a 100-km-wide tectonic suture zone that occurs between the colliding North American and Caribbean plate boundaries. The area of interest comprises a series of deep-seated regional fault systems that extend east-west across central Guatemala and neighbouring Honduras.
“It’s a confused mixing zone,” said Robert Wasylyshyn, the company’s vice-president of exploration, who spoke with The Northern Miner on-site. “It’s two continents that aren’t slamming into each other but are rubbing past each other, so there is a lot melanging and mixing going on. There’s a lot of misunderstood stratigraphy and structure.”
The deep-seated structural history, combined with favourable rock types, provides a ripe setting for plumbing systems and the introduction of silica-rich, precious metal fluids. In the two and a half years since Radius did its first deal in Guatemala, the Vancouver-based junior has acquired more than 3,000 sq. km of mineral concessions covering 150 km of strike length along the Jocotan regional fault system. “It’s pretty hard to find a prospective epithermal belt this size that nobody has worked, and no competition,” enthused President Simon Ridgway. Recognizing the potential of the underexplored Central American country early on, Ridgway led Mar-West Resources to Guatemala in 1997, following the end of a 36-year civil war. (Mar-West was subsequently taken over by
Flushed from its success in Honduras with the discovery of the San Martin gold deposit, Mar-West followed in May 1998 with the Cerro Blanco gold discovery in southeastern Guatemala after targeting hot-spring-style occurrences.
At Cerro Blanco, Glamis has since defined a potentially minable open-pit resource of 1.8 million oz. gold-equivalent in 21.7 million tonnes grading 2.3 grams gold and 16 grams silver per tonne. Glamis recently began a drilling program at Cerro Blanco as part of the first steps in moving the project forward to the feasibility stage.
Following the Mar-West takeover, Ridgway returned to Guatemala at the helm of Radius, and, in December 1999, acquired the right to a 100% interest in the Tambor project, 40 km northeast of the capital city. Radius spent the better part of the next two years concentrating its efforts in and around Tambor, uncovering gold mineralization in various settings. After completing a first pass of drilling on three prospects that failed to match surface expectations, Radius optioned the westernmost portion of its holdings to
The Gold Fields option has given Radius the freedom to begin exploring its eastern Guatemalan holdings covering some 2,700 sq. km of underexplored terrain. An experienced 6-man team of geologists has been hitting the ground hard since November 2001, identifying and following-up on several epithermal gold occurrences in a highly prospective belt of Cretaceous carbonates overlain by Tertiary volcanics in a 75-by-50-km area of interest.
Radius has made a grassroots discovery at the Holly project, a 3-hour drive east of the capital city. Initial reconnaissance sampling along a cut of the main highway returned a couple of 1 grammers from a red-stained colour anomaly in weathered clay altered volcanics. Radius returned to the showing and took 10 more chip samples, hitting 33 grams and 9 grams. “We then dropped a crew on it and started soiling and mapping,” says Wasylyshyn. “It initially looked like it was going to be something east-west and related to this Jocotan system, and it was looking like a bulk-target, given the style of alteration.” Continuous channel-sampling along a road-side exposure, just off the highway cut, returned 55 metres of 1.34 grams gold.
Radius made a deal with the underlying property holder, Mayan Minerals, to purchase all their rights and concessions in Guatemala, including the Holly and Jocotan properties, for US$30,000. The money would be put into escrow until all their concessions had been brought up to speed by paying all back taxes and filing all back reports, which have now been done. A Guatemalan exploration licence is good for three years and can be renewed twice, each renewal period being two years.
Further sampling
The geochemical data from more than 700 soil samples have revealed anomalous gold concentrations over an area of 1,200 by 1,000 metres and a vertical range of 450 metres. Still open for expansion, Radius is pushing the soil grid a further 500 metres to the south and a couple hundred metres to the north, with another 700 samples. The soils show a north-south orientation to the mineralization.
After discovering the Highway showing, Radius starting finding narrow quartz vein mineralization on the ridge tops and down the hillsides, including some bonanza grades. One showing on the Holly Ridge prospect returned 321 grams gold and 216 grams silver across 6 metres of chip sampling. “Rock-grabs are part of our standard prospecting,” said project geologist Jock Slater. “We use the soils to get grid data. We’re finding a new discovery or a small zone every week.”
The quartz veins are oriented north-south along a predominant 160 azimuth across the property and appear to be related to a north-south graben extensional feature coming off the east-west-striking Jocotan structure. Clay alteration and quartz veining have been mapped over an 8-sq.-km area. The quartz veining is observed in quartzites atop the ridges and phyllites down-slope.
“While we haven’t [ruled out] a bulk-style target, our sampling has indicated more of a high-grade bonanza vein-type target,” said Wasylyshyn. The company’s work to date has identified roughly six north-south-striking vein swarms or corridors. Limited outcrop exposure has Radius attempting to confirm and track the vein mineralization through hand-trenching, with varying degrees of success.
Karen
Trenching on the Karen zone returned 132 grams gold and 7,500 grams silver across 0.75 metre at a site several hundred metres down-slope from the Holly Ridge showing. Although the soil anomalies of the two prospects are oriented along a 160 azimuth, the two veins appear to be striking in different directions. “It’s still very much at the discovery stage right now,” cautioned Slater.
Added Wasylyshyn: “We’re still trying to connect the dots. Maybe there is a fault offset, or maybe there is pinching and swelling. Our objective is to get a few trenches on each of the zones, make sure they line up, and then drill a fence of holes across them and see what this thing does at depth.”
In the meantime, Radius is carrying out reconnaissance work farther to the east along the Jocotan regional structure, while paying close attention to crosscutting north-south graben extensions in Miocene rhyolitic volcanics. “These seem to be the three keys to the mineralization,” said Slater.
Initial work on the Agua Zarcas, Jocotan and La Cieza properties have all yielded encouraging numbers, indicative of a high-le
vel epithermal signature. Each of these prospects is targeted for follow-up work.
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