SEMAFO Discovers High Grade Siou Zone at Mana Including Values of Up to 12.56 g/t Au (20.08 g/t Au Uncut) Over 12 Meters
Montreal, Quebec, August 29, 2012, 09:30 EDT – SEMAFO (TSX, OMX: SMF) today announced the discovery of the new high grade Siou zone, located approximately 15 kilometers east of the Mana Mill and 22 kilometers North-East of Fofina. To date, initial results have returned consistent high grade values over more than one kilometer along strike and the Siou zone remains open. Preliminary metallurgical tests are underway.
The Siou zone is located along the Kokoi Trend, a north-northeast trending magnetic lineament, which can be traced over a distance of approximately 30 kilometers. Recent auger drilling results from along the trend showed a coincident gold geochemical anomaly, including the Siou anomaly that can be traced for a minimum of one kilometer. Follow-up drilling on the Siou anomaly included a total of ten sections covering two kilometer strike length (Figure 1). Sections are generally 200 meters apart. Three core holes were also drilled near the center of area in order to obtain geological information on the new discovery.
Drilling to date indicates that the Siou area is covered by a thin overburden cover followed by a saprolitic and transitional horizon measuring approximately 50 to 80 meters thick, before transforming to fresh bedrock (Figure 2). The mineralization occurs at the contact between a sedimentary unit (wackes and shales) to the west and a granodioritic intrusive unit to the east. The contact between the two units is characterized by shearing, quartz veining, and sericite alteration over thicknesses of 5 to 25 meters; the sheared contact dips approximately 45 to 60 degrees to the east. The shallower dip of the zone therefore remains within the oxidized horizon’s approximate 100-meter down dip.
Gold mineralization is associated with abundant quartz veining and silicification principally within the intrusive side of the contact. Although sulphide mineralization appears relatively weak, gold values obtained have generally been high, particularly within the most silicified areas. One core hole (WDC-513) also shows traces of visible gold grains, indicative that coarser gold occurs within the vein.
The limited drilling completed to date shows a one-kilometer section of the shear zone containing abundant quartz veining and high gold values, albeit some pinching and swelling is to be expected with this type of mineralization style. Parallel zones have also been identified locally, while their continuity will require additional drilling to establish their significance. In addition, the Siou trend seems to correlate with the Kokoi zone where limited drilling completed in 2010 returned values of up to 2.57 g/t Au over seven meters. The Kokoi zone is located approximately four kilometers south of the Siou discovery. The four-kilometer strike length between the Siou and Kokoi areas remains untested.
“The Siou zone once again shows the
geological potential at Mana with yet another mineralization style
discovered on the property,” said Michel Crevier, SEMAFO’s
Vice-President Exploration and Mine Geology,
“Further diamond drilling is currently in progress between the Kokoi and Siou areas. Once completed, closer spaced drilling will be carried out along the more strongly mineralized areas.”
Michel Crevier, P.Geo MScA, Vice-President Exploration and Mine Geology and SEMAFO’s Qualified Person has reviewed this press release for accuracy and compliance with National Instrument 43-101.
All individual samples represent approximately one-meter in length of core, which was sawn in half. Half of the core is kept on site for reference and its counterpart is sent for preparation and gold assaying at the ALS Minerals Lab in Ouagadougou, Burkina Faso or at SEMAFO’s Mana Mine Lab which uses separate sample preparation equipment exclusive to exploration samples. For RC and air core drilling, all individual samples represent approximately one-meter in length of rock chips homogenized and riffle-split to roughly a two-kilogram subsample, which is sent for preparation and gold assaying at the ALS Minerals Lab or at SEMAFO’s Mana Mine Lab. Each sample (core, RC, and air core) is fire-assayed for gold content on a 50-gram subsample. In addition to ALS Mineral Division’s own QA/QC (Quality Assurance/Quality Control) program and Mana Lab’s own QA/QC program, an internal quality control and quality assurance program is in place throughout the sampling program, using blind duplicates, blanks and recognized industry standards at both ALS samples and Mana Lab samples.
Figure 1 (Click to enlarge)
Figure 2 (Click to enlarge)
August 29, 2012 (Source: SEMAFO)
Disclosure: SEMAFO is a Vulture Bargain Candidate of Interest (VBCI). Members of the GGR team may hold long positions in SMF.T or SEMFF.