The mineral right MR143GP is held by Blyvoor Capital, a registered subsidiary (74%) of Blyvoor Resources.
The remaining 26% ownership of Blyvoor Capital is held by Blyvoor Empowerment Partners (RF) (Pty) Ltd, which represents Black persons as defined in terms of the Black Economic Empowerment (“BEE”) Act and as set out in the Mining Charter.
The MR143GP was issued prior to gazetting of the 2018 Mining Charter which requires mines to hold a 30% BEE representation, thus the 26% BEE requirement of the previous Charter remains in force.
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Summary:
Blyvoor falls within the Carletonville Goldfield, or Far West Wits Line, that, in addition to gold, produced uranium and pyrite (for sulphuric acid production) as by-products. The goldfield is stratigraphically subdivided into the Blyvooruitzicht, Main, Randfontein, Luipaardsvlei, Krugersdorp, Booysens, Kimberly and Elsburg Formations (SACS, 2006). Per Robb and Robb (1998), each formation is characterised by a regionally persistent basal unconformity-bound conglomerate and overlain by quartzites, grits and pebble bands, while argillaceous quartzites and shales are confined to the Booysens and Robinson Formations.
At the base of the Central Rand Group, the Blyvooruitzicht Formation quartzites and sporadic conglomerates occur and is disconformably overlain by the Main Formation. The base of the Main Formation in the Carletonville Goldfield is defined by the Carbon Leader Reef. The Carbon Leader is overlain by a siliceous quartzite of the Main Formation up to 3.5 m thick. Quartzites with intercalated conglomerates of the Randfontein and Luipaardsvlei Formations overlie the Middelvlei Reef. The Krugersdorp Formation quartzites grade upwards into the upward-coarsening Booysens Formation shale. The thin conglomerate of the sporadically developed Kleinfontein Reef forms the base of the quartzitic-conglomeritic Kimberley Formation. In the western sector, the Channel Shale is locally present. The Libanon Reef occurs on a marked disconformity within the Kimberley Formation. Quartzites of the following Elsburg Formation coarsen upwards. Several conglomerate horizons are developed in the Mondeor Formation.
Mineralisation and Deposit Type
Gold and uranium deposits in the Witwatersrand Basin are hosted by quartz-pebble conglomerates, which are generally less than 2 m in thickness and developed on laterally continuous unconformity surfaces. These reefs are generally characterised by shallow dips of between 10° to 25° and thicknesses of 1.0 m to 2.5 m that make them suitable for exploitation by means of typical narrow stoping techniques.
The gold deposits of the Witwatersrand Basin are considered to be associated with coalesced fluvial braidplains, where gold was concentrated within braided stream gravels developed on unconformities which have been correlated around the basin.
Most early theories on the origin of gold believed the gold to be deposited syngenetically (placer theory) with the conglomerates or by epigenetic means (hydrothermal origin), but subsequent research by Kirk et al (2004) concluded that metamorphism caused the post depositional local redistribution of gold (modified placer theory).
Generally, gold occurs in native form often associated with pyrite (less commonly pyrrhotite) and carbon, with quartz as the main gangue mineral.
At Blyvoor, two economic placer horizons have been exploited. These are namely the Carbon Leader and Middelvlei Reefs and occur in quartzites of the Main Reef Conglomerate Formation of the Johannesburg Subgroup of the Central Rand Group. The auriferous conglomerates dip uniformly at 22°S.
The Carbon Leader is a high grade, predominantly thin (<40 cm) carbon-rich reef and is the principle economic horizon at Blyvoor. The origin of the carbon is in debate as to whether it originated hydrothermally or from algae. Within the deeper southern section of the Mine, carbon is scarcer and hence likely responsible for the decline in grade.
In the western area, the Carbon Leader is eliminated by a northwest-southeast striking, 1,900 m wide erosional channel. The erosion channel is truncated to the north by the Master Bedding Fault. Its eastern boundary is well defined by mining, while the western boundary is less certain and has only been defined by drilling.
The Carbon Leader is divided into seven facies areas, namely F1 to F7, based on channel width and carbon content. Four types of Carbon Leader are recognised:
• carbon seam;
• channel reef;
• thin single reef;
• thick single reef.
Grade generally decreases down dip (south) and towards the west associated with a reduction in carbon.
The Middelvlei Reef is the second economic horizon at Blyvoor and lies stratigraphically 50 m to 75 m above the Carbon Leader. Towards the south, the separation increases due to a minor angular unconformity. The Middelvlei Reef is characterised by lower grades than the Carbon Leader. Owing to the variable payability and presence of sedimentologically controlled pay shoots, the Middelvlei Reef has been mined in scattered payable areas and is present over the whole lease area.
On the Middelvlei Reef, facies areas have similarly been identified using grade, channel direction and reef characteristics.