The Reko Diq Project is owned by the Reko Diq Mining Company (Private) Limited (RDMC) which is indirectly owned 50% by Barrick and 50% by Pakistani stakeholders.
The 50% Pakistan stakeholder interests in RDMC comprise a 10% free-carried, non-contributing share held directly by the Provincial Government of Balochistan (the GoB), an additional 15% held by the GoB indirectly through Balochistan Mineral Resources Limited (BMRL) a special purpose company wholly owned by the GoB and 25% indirectly owned by the Government of Pakistan (the GoP) through three Pakistani state-owned enterprises (the SOEs), Oil & Gas Development Company Limited (OGDCL), Government Holdings (Private) Limited (GHPL) and Pakistan Petroleum Limited (PPL). The SOEs hold their interests (in equal thirds) through Pakistan Minerals (Private) Limited (PMPL).
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Summary:
Deposit Types
Copper, gold, and molybdenum mineralization is interpreted to be associated with a regional scale porphyry system. On a global scale, porphyry deposits are concentrated around the Pacific Rim, China through Uzbekistan and into Eastern Europe, Iran and Pakistan. These regions coincide with convergent plate boundaries and include oceanic island arcs and continental (Andeantype) arcs. Groups of deposits or clusters occur within a few kilometers of one another and close or within major fault zones. Multiple deposits can form in belts over 100 km long, with the dimensions of each cluster up to 10 km laterally. Some deposits are within porphyry intrusions, whereas others are proximal to, or even distal from, intrusions.
Wide alteration haloes surround porphyry deposits, with estimates that some are 10 km3 to 100 km3 in volume and extend to at least 2 km from the core (Kouzmanov & Pokrovski, 2012). Alteration zones are typically referred to as potassic, sodic–calcic, sericitic and argillic, with a chlorite–sericite zone as well (Figure 8-1). More distal alteration includes chloritic and propylitic zones. The majority of these zones have been identified at Reko Diq.
Vein networks are a fundamental component of porphyry deposits and have multiple orientations and cross- cutting relationships that may allow local distinction of veins by their relative ages and by the vein and wall-rock alteration mineral assemblages. Individual veins may be only millimetres thick, and it is the frequency and grades of such veins that are important economically.
A supergene system like the one found at Tanjeel is uncommon in the Chagai region. This is a copper hypogene deposit with a moderately well developed, sub-horizontal, supergene enrichment blanket. The system is relatively small compared to the Western Porphyries. Tanjeel is a pyritechalcocite system with pyrite-chalcopyrite hypogene underlying system.
The Western Porphyries display a minor, <50 m, leach cap with primary mineralization occurring at surface. Rapid uplift of the system, lower sulphide content, and limited exposure to meteoric fluids have frozen the development of the system and limited the extend of leaching.
Property Geology
The main outcropping units within the Project are sub-aerial volcanic units within the Reko Diq Formation. These units contain porphyritic andesites, autoclastic volcanic breccias and pyroclastic lapilli and breccias which can be 400 m in thickness locally. This formation was dated between 23 and 25 Ma and was based on K-Ar and U-Pb zircon samples (Perello et al., 2008).
The Reko Diq Formation sits conformably above the Dalbandin Formation with a transition zone of interfingered lava flows, breccias, and conglomerates. The Dalbandin Formation is a volcanogenic sedimentary unit of sandstone, siltstone, and mudstone with local lenses of gravel units.
Mineralization is hosted in a series of intrusive rocks of diorite to quartz-diorite composition that have intruded the Dalbandin and Reko Diq formations. These intrusions are fine to medium-grained with porphyritic textures. The alteration halos radiate from these units outwards with mineralization occurring within the intrusive and altered wall rock. The intrusions occur as stocks, dykes, sills, and dyke swarms, with units typically ranging in size but have diameters less than 3 km. Multiple intrusive events are recognized based on changes in chemistry, texture, metal content, and spatial distribution, with the main mineralized intrusions dated between 10 Ma and 23 Ma.
Mineralization
Mineralization at the Western Porphyries is primary hypogene mineralization. The dominant copper mineral is chalcopyrite with an increase in bornite at depth. Extensive pyrite is found in the system (generally less than 4%) with minimal oxide mineralization identified. Where oxide mineralization has been defined it typically occurs in the top 50 m within the weathering horizon. Weathering is seen as minor oxidation and increased fracturing, with very little saprolite occurring.
The copper concentration >0.2% occurs at the surface with increasing grades at depth towards the bornite rich zones. A range of sulfide zoning has been identified and separated by pyrite dominant to chalcopyrite dominant to bornite dominate with various intermediate stages.
There is no direct correlation globally between copper and gold with gold typically associated with the bornite where it is found within the crystal matrix. Gold is also found in pyrite in HS/LS type mineral assemblages at shallow depths. Within the bornite rich zones, gold is approximately 1:1 on a % copper to g/t gold ratio. Where copper has been leached, or gold is present in pyrite this ratio can increase to over 2:1.
Gold is also associated with quartz in the system however is not recoverable due to its limited occurrence, low grade, and cost of recovery. Please refer to Section 13 for additional information.
Tanjeel is a distinctly supergene system with surface copper oxide common which occurs as malachite, copper wad, as well as chalcanthite where exposed chalcocite has oxidized. The HCC zone represents the richest of the supergene blanket and is dominantly chalcocite and pyrite. The pyrite content at Tanjeel can reach over 10% accounting for the required generation of sulphur to mobilize copper in the supergene system.
Within the EN and ENL zones there is minor covellite along with the more dominant chalcocite. These zones also exhibit strong pyrite zoning and veining. At depth the hypogene system is characterized by chalcopyrite and pyrite.
The MIX zones at Tanjeel that follow down dip structures are surface fluid pathways that allow oxidation to occur. These zones are characterized by oxide development at depth with malachite and chalcocite co-existing in the same structures. These zones also show chalcanthite infillings where oxidation of the chalcocite have occurred.