Afar Depression
In November 2009, Stratex announced the discovery of significant new low-sulphidation gold mineralization at the Megenta project in the Afar Depression region of Ethiopia (see Figs. 1 and 2). Since identifying the potential of the region for hot-spring-related gold deposits, Stratex has moved rapidly to acquire an extensive land position in the wider Afar Depression. This includes a recent expansion into Djibouti, which borders Ethiopia to the east and hosts the geological extension held within the Company's Tendaho licences in Ethiopia (Fig. 1). The Company's total land package in the Afar Depression is now 2,780 km².
Tendaho - Megenta
Tendaho is located within the Afar Depression region of eastern Ethiopia. Stratex's Exclusive Exploration Licences (EEL) here cover a total area of 2,245 km² and are valid for three years. The Megenta discovery was Stratex's first discovery within the Tendaho licence package and was identified during regional work, with alteration and mineralization observed over 5 km2. Stratex has submitted a work programme to support the application and there are no financial commitments with respect to the EEL's.
A six week detailed mapping and sampling programme has recently been completed at the Megenta hot spring gold prospect and Stratex now aims to define drill targets for Q4 2010. Initial results from the recent channel-chip sampling programme north of the Awash River have returned grades of up to 3.27 g/t Au over 0.62 m within silicified structures at the Canal Zone (Fig. 2) and 2.72 g/t Au from samples of silicified sandstone, possibly highlighting a potential.
South of the Awash River, a higher-grade zone, the “Hyena Zone” (Fig. 2), yielded a highest surface value of 16.75 g/t Au (with 8.8 g/t Ag) from a prominent 0.5 m-wide silica rib. A further lower-grade zone, the 500 m-long “Gazelle Zone”, also contains significant values including 2.46 m grading 2.29 g/t Au. Please see the exploration section below for more details.
Recognition of the Megenta hydrothermal system clearly highlights the potential of the rest of the Afar Depression for low-sulphidation epithermal gold systems, some of which have been more deeply exhumed than Megenta. A key feature of the Nevada deposits is their tendency to cluster along key controlling structures. With a greater level of understanding of the Megenta structural framework the directors believe that there is potential for further discoveries in this region.
Regional targeting of the wider Tendaho licence area, based on knowledge of controls on mineralization at Megenta, will be undertaken prior to field evaluation.
Geology
The prospect comprises high-level steam-heated sinter underlain by opaline and chalcedonic silica (see Fig. 3A) containing anomalous levels of gold (up to 57 ppb). A number of feeder structures comprising fine chalcedonic silica veins were discovered, extending over lengths of 500 m, containing highly significant gold values of 0.328 g/t Au, 0.218 g/t, 0.132 g/t Au, and 0.126 g/t. These numbers are significant as normally at this high level in such systems gold values are often negligible. Anomalous concentrations of arsenic, mercury, selenium and thallium were also identified and are typical of the trace element suite associated with this style of mineralization. The area of silicified and hematitic sediments extends as far as 300 m away from the veins. The host rocks to the feeder structures are Pleistocene lake sediments that have been intensely silicified and mineralized with hematite adjacent to the vein structures. The preservation of the steam-heated sinter demonstrates that the top of the system is preserved and therefore that there is considerable potential for the discovery of a large vertical extent to the sub-surface mineralization.
Dr. Sillitoe, subsequent to a five day field visit and review of geochemistry, reported that the high-level preservation of the Megenta prospect (Fig. 3A) is also similar to shallow exposure levels and near-palaeosurface features observed at the sites of the Midas, Hycroft and Wind Mountain mines located in the Great Basin in Nevada. Stratex therefore considers the Megenta prospect to have potential for large low-grade bulk-tonnage mineralization (Fig. 3B), similar to the Hycroft Mine in western Nevada which has produced 1.2 Moz and has a remaining resource of 393.91 Mt grading 0.4 g/t Au (using 0.17 g/t Au cut-off) for 5.095 Moz. In addition Stratex will be investigating the potential for bonanza gold veins beneath the high-level sinters (Fig. 3B). The low-sulphidation Sleeper Mine in western Nevada, for example, produced 1.66 Moz from veins grading > 15 g/t Au.
Common to all the Nevada project areas is the strong structural control on mineralization, proximity to hot-spring activity, and a typical geochemical association of gold with arsenic (‘As’), mercury (‘Hg’) and antimony (‘Sb’). The trace element association at Megenta is typical of hot spring low-sulphidation epithermal gold systems with arsenic , mercury and antimony being reported. However, it must be noted that the levels of these elements is low. As is commonly greater than 50 ppm with a maximum value to date of 184 ppm, Hg is commonly greater than 0.1 ppm with a maximum value to date of 2.28 ppm and Sb is commonly greater than 1 pm with maximum value to date of 5.58 ppm.
Furthermore, fluid boiling textures associated with white banded chalcedony, akin to those of Midas have been observed at Megenta. These are key indicators of potential high-grade gold and silver precipitation.
Exploration
Following initial reconnaisance work at Megenta, Stratex has recently undertaken detailed geological and structural mapping, along with channel chip rock sampling.
Of the total 817 samples collected to date, over a total sampling area of 5,000 m by 500 m, only 20 (2.4%) returned non-detectable gold (<0.005 g/t Au), 253 (31%) returned equal or greater than 0.1 g/t Au, with further 54 (6.6%) returning equal or greater than 0.5 g/t Au.
Sampling focussed on silica structures, specifically on zones containing chalcedonic ribs and veinlets, which potentially indicate the top of wider veins at depth. North of the Awash River, sampling of the so-called Canal Zone (Fig. 2) that permits access to the deepest exposure in the system, some 20 metres below the surface, returned significant and encouraging grades including 0.62 m grading 3.27 g/t Au. In addition, samples of silicified sandstone taken from this zone returned 2.12 and 2.72 g/t Au and highlights the potential for bulk-tonnage mineralization at the property.
South of the Awash River two further zones have been identified, the Hyena and Gazelle Zones (Fig. 2). The Hyena Zone yielded a highest surface value of 16.75 g/t Au (with 8.8 g/t Ag) from a prominent 0.5 m-wide silica rib and appears to be related to intersecting structures defining an area of maximum dilation and hence fluid circulation, which is a common gold foci within epithermal systems. Further detailed mapping will be undertaken to test this concept prior to defining drill sites for testing this major new low sulphidation discovery. The 500 m-long “Gazelle Zone”, located 500 m to the north-east of the “Hyena Zone”, also contains significant values including 2.46 m grading 2.29 g/t Au.
History
Stratex conceived the original programme in association with leading independent economic geologist Dr. Richard Sillitoe who wrote an article "Rifting, Bimodal Volcanism and Bonanza Gold Veins" in 2002. The rifting environment of western Nevada with bimodal volcanics was used as model for this setting. The Main Ethiopian Rift shares many characteristics with this environment including intracontinental rifting and bimodal (rhyolite and basalt) volcanism.
Djibouti
In June 2010 the Company expanded its activities into Djibouti, having been awarded six licences covering an area of 535 km². These licences cover the geological extension of the Company’s Tendaho licences in Ethiopia where the initial discovery of the Megenta gold occurrence has led to the identification of a number of Rift settings with the potential for hosting gold.
The Djibouti licences have been granted for an initial period of two years and thereafter are extendable for two further periods of eighteen months each. Stratex holds a 90% interest in the licences, with the Djibouti government retaining a 5% interest and has the right but not the obligation to purchase a further interest, up to a maximum of 35% by funding the costs of the required capital investment for mine construction, following completion of a successful exploration programme and a feasibility study. Stratex also has an agreement with the founding partners of former Djibouti-focussed exploration company Green River Geology for their entire exploration database in return for a 5% interest in any concession. This interest can be purchased by Stratex for US$2 million upon a decision as to production.
Historical surface sampling and drilling on alteration targets by Green River Geology has already confirmed presence of Megenta-type gold mineralization in Djibouti and Stratex’s management believe that, like Megenta, this extension to the Afar Depression play could hold similar epithermal systems as those found at the Cerro Vanguardia mine in Patagonia, and the Sleeper mine in Nevada. The Company's total land package in the Afar Depression is now 2,780 km².
To expedite the administration and management of the Djibouti holdings and exploration Stratex has appointed Dr. Franco Maranzana as lead consultant for the Djibouti project. He has 40 years experience in project management and assessment of natural resources, evaluation of mineral potential, natural risks mitigation, and environmental factors. Franco has had longstanding international exposure, and has been involved with Governments and international organisations in projects world-wide.
The directors have found the government authorities to be very supportive of Stratex’s plans and anticipate that exploration will commence in the near future.
