OPERATIONS
OPERATIONS
Impala entered the global arena when it strategically acquired the Canadian PGM miner,
North American Palladium.
At the Rustenburg operation, both the Merensky and UG2 Reefs, which are
contained in the Rustenburg Layered Suite, a well-layered ultramafic to mafic
igneous succession on the 2-billion-year-old Bushveld Complex, are present
throughout the lease area. Both reefs sub-outcrop on the mining area and dip
about 10 to 12 degrees towards the centre of the complex, although locally dips
may increase to 15 degrees. The vertical separation between the Merensky and
UG2 reefs varies from about 125m in the south to some 45m in the north.
Platinum in the eastern limb
Marula is one of the first operations to have been developed on the relatively
under-exploited eastern limb of the Bushveld Complex in South Africa. Mining
activities target only the UG2 reef, which is accessed via two decline shaft
systems. Driekop Shaft uses a hybrid mining method, while at Clapham Shaft,
both hybrid and conventional mining methods are used. In the hybrid sections,
all main development is done on reef, and stoping is carried out through
conventional single-sided breast mining from a centre gully. Panel face lengths
are approximately 16m to 24m and the stoping width averages 1.25m. For
the conventional operation, the footwall drives are developed on strike about
25m below the reef horizon with crosscut breakaways about 220m apart.
Development is undertaken with drill rigs and dump trucks, while stope face
drilling is done with handheld pneumatic rock drill with air legs.
Both the Merensky and the underlying UG2 reefs are present and sub-outcrop
in the Marula mining right area. The reefs dip generally in a west-southwest
direction at 12 to 14 degrees with a vertical separation of some 400m between
them. Potholes represent the majority of the geographical losses encountered
underground, while a small dunite pipe also disrupts the reef horizon.
At Two Rivers, on the southern part of the eastern limb of the Bushveld Igneous
Complex, both the Merensky and underlying UG2 Reefs occur on the property.
However, only the UG2 is currently exploited. The UG2 outcrops in the Klein
Dwarsrivier valley over a north-south strike length of 7.5km and dips to the west
at about seven to 10 degrees. The vertical separation between the Merensky and
UG2 Reefs is about 140m to 160m.
Due to the extreme topography, the Merensky reef outcrops further up the
mountain slope and also results in the UG2 occurring at a depth of 1650m
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African Mining January 2020
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African Mining January 2020
www. africanmining.co.za