ROCK REINFORCEMENT
A close bond
Weber Mining & Tunnelling Group through its partnership with Epiroc recently assisted in the bolting operation of a mine using Epiroc ' s new Boltec with automated resin injection capabilities
For this year ’ s ground support review , Paul Moore focuses on the chemical and concrete side of the business including the shotcrete , resin and fibre technology that supports bolting in many underground mining situations
Consolidation is at play in many mining technology markets today and ground support / rock reinforcement is no exception . With the acquisition of MBCC Group in May 2023 , Sika further enhanced its strength in rock reinforcement solutions underground in many parts of the world . But the global picture for the acquisition is complex which deserves some explanation .
To comply with regulatory requirements , Sika sold MBCC Group ’ s Admixture Systems business including assets in the UK , the USA , Canada , Europe , Australia , and New Zealand to the international private equity firm Cinven . In those countries only the Construction Systems portfolio of Master Builders Solutions is part of Sika ( except for Australia and New Zealand , where also the Construction Systems portfolio of Master Builders Solutions has been sold to Cinven ). In all other countries , the portfolio remains unsplit and both businesses , Admixture Systems and Construction Systems , are fully owned by Sika . Sika uses the trademark ‘ Master Builders Solutions ’ under license from Construction Research & Technology GmbH , Germany .
Under the Master Builders Solutions brand in the applicable regions including South America , Africa and Asia , MBCC Group offers a unique set
of high-performance products for the mining sector .
Looking at admixtures for sprayed concrete , while the MasterEase range provides superior rheological properties ( good pumpability , low viscosity ), the MasterSuna SBS / RCA range is specifically designed to utilise manufactured sands with high fines and / or clay minerals . The hydration control system MasterRoc HCA is capable of maintaining an open time of up to 72 hours , allowing for total flexibility of site logistics . The viscosity modifying admixtures ( VMA ) of the MasterMatrix range allow the modification of rheological properties to prevent segregation .
MasterRoc MS microsilica improves the pumpability and workability of sprayed concrete mixes in the fresh state while reducing permeability and increasing density as well as long-term strength in the hardened state . MasterRoc TCC is a concrete improving admixture which enhances the quality in the hardened states by reducing shrinkage and improving bonding .
MasterRoc SA alkali-free accelerators are added at the nozzle and accelerate the setting and hardening of the sprayed concrete . They provide high early strength gain and long-term strength development , as well as enhanced durability . Furthermore , they reduce dust and rebound levels . The accelerators are also suited for applications where extremely thick layers of sprayed concrete are required .
Fibre reinforced sprayed concrete is a widely used rock support measure which replaces the conventional mesh reinforcement and can be applied safely , fast and highly mechanised . The structural synthetic macrofibres from the MasterFiber product range form an internal network and add superior tensile properties to the sprayed concrete system . MasterFiber structural reinforcing fibers greatly improve the load bearing capability and cracking resistance of sprayed concrete . In comparison to steel fibres , the synthetic fibres are not prone to corrosion and show a better CO2 footprint .
The use of synthetic fibres guarantees a very ductile behaviour of the concrete structure , which ensures very big deformation before failure . In hard and soft rock mining , changes in humidity and temperature affect weak strata , causing rock falls and rib degradation . Effective surface support and protection against weathering of rock and strata are critical to the safety , efficiency and longevity of any mining operation . Master Builders Solutions provides systems for supplementary surface support to strategic areas of a mine , thus increasing safety for people and infrastructure .
Sika also has its own concrete and shotcrete technologies which contribute to efficient mine
International Mining | AUGUST 2024