The Tasiast deposit is located in north-western
Mauritania, within the Archean-aged
Aouéouat greenstone belt, a 70 km by 15 km north-south trending belt situated
within the SW sector of the Reguibat Shield. The property is approximately 300 km north of
the capital Nouakchott and 250 km southeast of the major
city of Nouâdhibou.
From 1960 to 1975, the area was subject to exploration work carried out
by the Mauritanian government. Soil
sampling conducted by the European Development Fund between 1993 and 1996 first
identified the Tasiast area as being anomalous in gold. Subsequent drilling, sampling and mapping by
various companies has resulted in a defined gold reserve of 26.47 Mt at 2.22
g/t gold with a further 8.90 Mt at 1.9 g/t (reported in 2008).
A series of four north-south trending greenstone belts fall within the
Tasiast licenses. Of these four, only Aouéouat contains large amounts of the
banded iron formations (BIFs) within which the deposit is hosted.
Mineralisation at Tasiast occurs on both limbs of a broad regional
antiform defined by BIF and cored by rhyo-dacitic to rhyolitic volcanics. The
two defined mineralised zones (the Piment Zone on the east limb and the West
Branch on the west limb) are approximately 1km apart. All mineralised zones
identified at Tasiast dip steeply to moderately to the east.
(Source: Technical Report on the
Tasiast Gold Mine, Islamic Republic or Mauritania for Red Back Mining Inc., May