MINERAL TARGET: GOLD
Moderate topography and good rock outcrop are typical at the Oweinat block.
The Oweinat property encompasses an expansive 1,245 square kilometre block (481 square miles) in Western Desert, of the Arab Republic of Eqypt.
The Oweinat block is north of the border between Egypt and Sudan, near the Libyan border. This area was essentially unexplored geologically prior to a program of regional scale mapping and prospecting jointly initiated in 1992 by the EGSMA (Egyptian Geological Survey) and IRC Libya. This work, which produced a geological map at a scale of 1:100,000 identified highly favourable Archaean terrain with abundant bodies of BIF (banded iron formation) within highly metamorphosed gneiss. Gold was found to be common within the BIF bodies, and in certain quartz veins, shear zones, dykes and alteration zones in the same areas. The Archaean rock outcrop constitutes about 10% of the exposures scattered about the block, but are thought to underlie at least half of the area. These rocks are locally intruded by younger granitic rocks, overlain by Cretaceous sedimentary rocks, and covered by sand sheets, wadi deposits and sand dunes.
Outcrop of BIF (banded iron formation). Note the distinct bands that are iron-rich or silica-rich.
Only two other companies are currently active in mineral exploration and development in the country. The International Finance Corporation, a private sector arm of the World Bank is working with Egyptian authorities to modernize mining laws over the next year.
According to various accounts, with Egypt's rich and diversified culture and history, ancient mining would have definitely played a major role in the development of high grade ore-bodies. None-the-less, modern exploration has not been carried out in Egypt, and as a result, the country has excellent potential for significant gold discoveries in particular. Egypt's mineral resource development is coordinated by the Egyptian Geological Mining and Survey Authority (EGMSA).
Isoclinal folding in BIF (banded iron formation). Folding in BIF is considered to be a favourble factor associated with gold mineralization. (pen for scale)
30 favourable areas within the Oweinat block identified by the regional work program were selected for follow-up work in 1996 to 1998, and again in 2000, including mapping at scales of 1: 50,000, 1:20,000 or 1: 5,000, trenching, grab sampling and channel sampling, and limited ground geophysical surveys. A bulk sample of 2.5 tons was collected and processed by carbon in pulp cyanidation, and returned 6.8 g/t gold. Ore microscopy identified fine-grained visible gold, which was confirmed by scanning electron microscopy. The favourable areas cover hundreds of square kilometers, and are generally focussed on Archaean rocks containing BIF and/ or quartz veins. Ultramafic rocks constitute a small percentage of the terrain, but are often spatially associated with gold enriched areas. The iron formations consist of magnetite, hematite and goethite, which is thought to be derived at least locally from pyrite. The terrain is not thought to be deeply weathered, as sulphide minerals are reported from surface samples in many areas, along with relatively fresh, easily identifiable metamorphic rocks.
Tight folding in BIF (banded iron formation). Gold mineralization is better developed in the folded portions of BIF. (pencil for scale)
Rock samples were initially analyzed by spectral analysis, and anomalous samples were re-analyzed by fire assay for gold. All analytical work was performed by EGSMA; their quality assurance, quality control procedures were not reported. Values up to 53 g/t gold over 20 metres were reported. Iron analyses are mostly in the 20 to 50% Fe2O3 range, with some large samples averaging 32%, however there may be potential for enriched areas among the dozens of BIF bands that are up to hundreds of metres thick, and extend for kilometers. Much of the favourable terrain is overlain by thin sand deposits; geophysical exploration methods will be beneficial for exploring in these areas.
Of the 30 widely separated blocks studied and sampled in detail, 11 areas returned analyses above 10 g/t gold and 25 returned gold analyses above 1 g/t by fire assay. Gold is reported from many geological environments within the Archaean terrain:
- most iron formation samples, including tabular sections of the strata in addition to structurally complex areas associated with dykes and veins;
- quartz veins typically described as smokey quartz with sulphides and breccia textures, 0.5 to 6 meters wide (1.6 to 20 feet) and several hundred metres long;
- quartz-sericite-pyrite (iron oxide) zones adjacent to veins, up to 10 meters (33 feet) wide;
- shear zones cutting serpentinite containing breccia cemented by iron oxides and quartz veins
- mafic and acid pyritic dykes;
- quartz-chlorite-sulphide masses hosted by serpentinite.
