Extremely competent granite creates fragmentation challenges The defining technical characteris- tic of Rheebok Quarry is the nature of its granite deposit. While the rock produces excellent aggregate products, it is extremely compe- tent and resistant to fragmentation during blasting. This creates one of the quar- ry’s most significant operational constraints. Even with carefully designed blast patterns and initiation systems, the granite frequently produces oversized boulders that cannot be handled efficiently by the primary crushing circuit without additional secondary breaking. As a result, secondary rock breaking has become a permanent and essential component of the operation rather than an occasional support activity. Rheebok currently operates two hydraulic peckers dedicated to reducing oversized material after blasting. These machines work continuously on blasted rock piles, breaking large boulders into sizes suitable for loading and primary crushing. The presence of the two peckers is not simply a convenience but a production necessity. Without them, excessive oversize material would soon create bottlenecks in the load- and-haul cycle, restrict crusher feed consistency and significantly reduce plant throughput. “The fragmentation is the big- gest challenge,” explains Clayton. “Because of the type of granite, the blasts generate large boulders and the peckers therefore become criti- cal to the operation.” Balancing blast performance and environmental control Blasting at Rheebok requires par- ticularly careful engineering due to both the geology and the quarry’s proximity to surrounding infra- structure and communities. The operation cannot simply increase powder factors aggres- sively in an attempt to improve frag- mentation because vibration control remains a critical consideration. Blast designs therefore need to strike a balance between sufficient
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Rheebok Quarry traditionally produces between 250 000 t and 300 000 t of aggregate annually which includes stone, crusher sand, base, sub-base, roadstone and ballast.
Rheebok currently operates two hydraulic peckers dedicated to reducing oversized material after blasting.
Blasting at Rheebok requires particularly careful engineering due to both the geology and the quarry’s proximity to surrounding infrastructure and communities.
Drone-assisted survey technology has become increasingly important in this process. Rheebok uses drone mapping and photogrammetry software to conduct volumetric surveys, monitor pit progression and improve stockpile management accuracy.
indicate that the quarry retains a minimum life-of-mine estimate of approximately 30 years, with the possibility of significantly extend- ing this as additional reserves are opened and future mining areas are developed.
SANRAL-linked road developments. The abrasive granite produced at Rheebok is particularly well suited to road construction applications because of its durability, hardness and resistance to wear. Recent reserve evaluations
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MODERN QUARRYING Quarter 2 | 2026
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