Malbex Resources Inc. (TSX VENTURE:MBG) announced results today from two holes at the Rojo Grande target on the Company's Del Carmen gold-silver project in San Juan province, Argentina.
The Rojo Grande target consists of reddish, iron oxide-stained silicified rocks outcropping on the north side of the massif that cores the Del Carmen Norte hydrothermal alteration system. Gold-silver mineralization at Rojo Grande occurs over a minimum strike length of approximately 500 metres (m) and remains open along strike and at depth. Holes DDHC-10-040 and -042 were collared between sections containing previously reported intercepts that include those about 100 m to the south.
"Today's results confirm the presence of high-grade zones within Rojo Grande," said Tim Warman, President and CEO. "Such high-grade areas bring us closer to our goal of defining a potentially economic, near-surface, oxidized mineral resource at Rojo Grande in the current drill campaign. We're currently planning a scissor hole through the high grade zone discovered in hole 42 in order to better understand its geometry."
With today's release, nine holes totalling 1,601 m have been reported from the 10,000 m program budgeted for the 2010/2011 field season at Del Carmen Norte. While one drill rig is delineating the Rojo Grande mineralization, the second rig is testing the controlled source audio-magneto-telluric (CSAMT) anomalies that appear to extend from Rojo Grande over a kilometre to the southwest under steam-heated alteration at Cerro Amarillo.
Malbex also reports today that 1,368 metres of diamond drilling were completed in six holes at its Despoblados project. Targets tested at Despoblados consisted of a CSAMT resistivity anomaly associated with a pull-apart basin (two holes) and outcropping low-sulphidation epithermal veins (four holes). No significant mineralization was encountered, with best assays of 0.66 g/t gold and 22.0 g/t silver (separate samples, 1.0 m core lengths). Malbex is currently reviewing all data from Despoblados to determine the future of the project.
Del Carmen results
DDHC-10-040 (azimuth 330°, dip 60°) and DDHC-10-042 (vertical) were drilled from the same platform. Both holes passed through less than 10 m of overburden and quartz-alunite alteration before entering typical Rojo Grande vuggy silica and silicification. Hole 040 intersected over 140 m of strongly silicified dacitic tuffs, volcanic breccia and probable hydrothermal breccias. Vuggy silica textures and variable degrees of goethite and jarosite coating fractures are observed in the silicified zone. The silicified rocks are succeeded below by strong clay alteration and significantly less competent core. Hole 042 passed through mainly vuggy silica with variable goethite and jarosite coating fractures and as disseminations until about 94 m before entering clay-rich and incompetent rock similar to that at the bottom of hole 040. Hole 042 was abandoned at 139.5 m due to drilling problems, and hole 040 was stopped at 204.5 m due to the challenging conditions of incompetent rocks and strong clay alteration.
Del Carmen Norte and Rojo Grande
Rojo Grande consists of prominent reddish weathering silicified outcrops on the northern flank of the massif of high sulphidation hydrothermal alteration at Del Carmen Norte. Silicified outcrops and geophysical data identify a shallow-dipping northeast-southwest striking, near-surface silicified ledge at Rojo Grande measuring approximately 800 m long by up to 300 m wide. Six diamond holes at Rojo Grande in the previous campaign intersected near-surface gold-silver mineralization in silicified rocks over an area about 200 m by 150 m.
Mineralization at Rojo Grande is generally hosted by vuggy silica and massive silicification with red-brown staining due to disseminations of fine-grained hematite, goethite and jarosite and as veinlets. Selective chip sampling of northeast-striking zones of hydrothermal breccias cemented by chalcedony and very fine-grained quartz that cut pre-existing silicification yielded samples with up to 10 g/t gold.
The silicified reddish outcrops at Rojo Grande are interpreted to be part of a sub-horizontal ledge (sheet) formed by preferential silicification and quartz-alunite alteration of volcanic breccias within the strongly argillic (illite) to advanced argillic (kaolinite) altered tuffs and fine-grained flows that dominate the andesitic volcanic sequence. The alteration is cut by northeast-, north-northwest- and east-striking fault zones. The mineralized intersections are bounded by changes in style of alteration, by faults or both. While some faults abruptly truncate silicification and thereby clearly post-date the hydrothermal events, hydrothermal feeder structures that controlled alteration and mineralization are inferred to preferentially coincide with one or more of these directions.
Del Carmen work program
The 147 km2 Del Carmen concession package is located near the southern end of the El Indio Gold Belt, and hosts the Del Carmen Norte and Del Carmen Sur high sulphidation epithermal gold-silver systems. The Del Carmen Norte hydrothermal alteration system covers approximately 9 km2. A second, less exposed, high sulphidation epithermal system occurs at Del Carmen Sur some 5 km to the south of Del Carmen Norte.
Del Carmen Norte consists of a strongly altered, sub-horizontal sequence of andesitic volcanic rocks that is cut by numerous faults. Volcanic breccias appear to be selectively silicified with silicification hosting mineralization sandwiched between less favourable argillic altered volcanic layers. Steep faults have strongly influenced hydrothermal fluid flow within the volcanic sequence. High-sulphidation alteration is therefore zoned outward from the combination of both lithological and structural controls on silicification. Controlled source audio-magneto-telluric surveying (CSAMT) in the previous field campaign identified elevated resistivity coincident with silicified rocks at Rojo Grande. Other larger CSAMT resistivity anomalies to the southwest are directly associated with steam-heated siliceous alteration at high elevations at Cerro Amarillo but continue to the depth limits of detection of the survey (roughly 500 m vertically).
In addition to Rojo Grande, other zones of vuggy silica and other styles of silicification, and enargite-bearing quartz veins on surface were drill tested in the 2009-2010 field campaign. The current drilling campaign at Del Carmen Norte is focused on defining the extent of gold-silver mineralization at Rojo Grande, testing CSAMT resistivity anomalies (including the large anomaly between Rojo Grande and Cerro Amarillo), and following up on encouraging initial drill results from Naciente Quebrada Pedregosa south of Cerro Amarillo.
Diamond drill hole samples consist of core that is sawn in half by electric saw on site. Core samples are sealed in new plastic bags, which are inserted into rice sacks for transport by Malbex personal or commercial trucking service to ALS Global prep lab in Mendoza. All samples are crushed and pulped and powders sent by ALS to one of their laboratories (typically La Serena, Chile or North Vancouver, BC). Fire assay for gold is conducted on 30 gram (g) pulps with atomic absorption finish. Over limits (>10 g/t gold) are fire assayed with gravimetric finish. In addition, all samples receive multi-element analysis including silver by ICP after aqua regia digestion and mercury by cold vapour atomic absorption.
Malbex's quality assurance-quality control (QA-QC) program consists of the insertion in every 20 samples of at least one certified standard of known gold content, one blank (sample known to consist of very low levels of gold to ensure adequate cleaning of the sample preparation equipment between samples) and one field duplicate. Samples of significant drill intercepts will be sent to two additional independent laboratories to verify gold and silver analyses when necessary. Metallic screen fire analyses for gold will also be run regularly on discovered mineralization as an additional QA-QC check. The half core remaining after sampling is stored in a Malbex-run facility in San Juan for verification and reference purposes.
Peter Stewart, PhD, Vice-President Exploration of Malbex Resources Inc., is a Professional Geoscientist in the Province of Ontario, and is the Qualified Person as defined by NI 43-101 responsible for the technical information presented in this news release.
Source: Malbex Resources Inc.