The Red Sea Hills

GEOLOGY

The Red Sea Hills of NE Africa correspond to a broad stretch of hilly to mountainous terrain along
the west coast of the Red Sea, from Egypt in the north through NE Sudan into NW Eritrea. They are
part of the Arabian-Nubian Shield (ANS), which consists of a collage of oceanic island arcs and
oceanic crust (ophiolite) between 1 billion and 550 million years (Ma) old, that was amalgamated
around 600-550 Ma ago during the so-called East African orogeny. Large granitoid intrusions were
emplaced during the latter. The Red Sea Hills’ mineral potential includes a.o. gold, copper, zinc,
lead, manganese, chromium, iron and tantalum in a range of mineralisation environments. A
present-day simile of the ANS before final amalgamation is the Western Pacific rim, including
Indonesia, the Philippines, the Japanese islands and the Western Pacific subduction zones.
The Derudeb South EPL is situated in the E-W trending remnant of an oceanic island arc in the
tectonic unit that is known as the ‘Haya terrane’. Island arc lithologies include mafic (silica-poor)
volcanic rocks of basaltic composition (lava flows and tuffs) and subordinate felsic (silica-rich)
volcanic lithologies (rhyolitic domes, flows, tuffs). Intrusive rock types include smaller, syn-volcanic
felsic and mafic bodies (granitoid, gabbro), large syn-orogenic granitoids, and smaller, wellindividualised
post-orogenic granitoids. The eastern part of the EPL is cross-cut by a small, N-S
trending rift basin of Tertiary age (Oligocene, 30-27 million years old) that is partly filled up with
mafic and felsic volcanic flows.
MINERAL POTENTIAL
Remote sensing desktop studies identified a major, 20 km-long felsic volcanic belt in the EPL with
good potential for base metals- and/or gold-bearing volcanogenic massive sulfides (VMS)
5
Ghazal Minerals Nov 2010 Snapshot
2 Defined in the CA as the “Exploitation of a Commercial Discovery for 90 consecutive days at 60% of full design
capacity as set forth in the construction program pursuant to which the Mine was built”
mineralisation, similar to the Ariab deposits further north in the Red Sea Hills. Gossans and/or
gossanous units of varying size, representing the weathered surface expressions of VMS bodies,
mostly composed of iron oxides but with anomalous base metals and gold values, were identified in
the field in all parts of the belt visited to-date. Similar felsic belts with similar potential occur in
other parts of the EPL, but have not yet been checked in the field.
The main prospect is the 750 m-long Abu Mahmud gossanous ridge in Target Zone 1 (TZ1, named
after the Jebel Abu Mahmud ridge to the south). Other promising targets occur in TZ2 and TZ3. At
surface at least, the Abu Mahmud prospect is in all aspects (size, rock facies, gold and base metals
grades) a near-perfect copy of the Hassaï deposit in the Ariab mining district. Deep meteoric
weathering in the Ariab area has leached base metals in the VMS to uneconomic values in the top
100 m of the profile, but has also concentrated gold to economic grades (see figure on page 11). Past
production at Ariab has focussed exclusively on this supergene gold potential and has led to the
extraction of some combined 2.2 Moz of gold in the various deposits (1 Moz at Hadal Awatib, 4-500
koz at Hassaï, the remainder from smaller bodies). Recent drilling in the unweathered VMS below
the Ariab open pits has produced the following resource figures (September 2009; currently being
upgraded and expanded with a high-density drill programme):
• Hassaï South: Inferred resource of 20.150 Mt of ore, containing 1 Moz Au, 561.674 Mlbs Cu and
79.295 Mlbs Zn, from 100 m depth (bottom of open pit) down to 300 m depth (and 400 m in the
central portion). The deposit remains open at depth, as is demonstrated by a deep drillhole that
intersected VMS mineralisation at 500 m below the pit floor, i.e. at 600 m below surface. There’s
also potential for a lateral extension to the west, particularly at depth.
• Hadal Awatib East: Indicated + inferred resource of 31.428 Mt of ore, containing 1.159 Moz Au
and 695.594 Mlbs Cu, from about 100 m depth (bottom of open pit) down to 400 m. The deposit
remains open both laterally and at depth.
In addition to the recognised VMS potential, the Derudeb South EPL contains large numbers of
several generations of quartz veins, some of which may host mesothermal, syn- to late-orogenic gold
mineralisation. Two small, high-grade magnetite bodies, associated with gabbroid intrusions, are also
known in the area. One of these has been estimated by earlier workers at 5-6 Mt of ore grading
65-69% Fe. Our previous fieldwork has further revealed the existence of significant tracts of marble
of various colours and has also identified large quartz-kyanite hills, some of which may contain a
significant kyanite resource.