GROUND SUPPORT & ROCK REINFORCEMENT
Weber Mining is a global leader in cavity filling foam solutions for mining cavities will be completely filled , a containment of the excavation is ensured due to the active filling support of the foam .
ROCSIL ® FOAM LS1 is a two component phenolic resin product used for cavity filling , air and gas sealing , fire fighting and stabilisation of highly fractured strata . Its most common use is to fill roof cavities formed by longwall roof falls . The mixing of resin and catalyst in a volume ratio of 4:1 produces an immediate foaming reaction followed by a rapid expansion of the product to as much as 35 times its original volume . After expansion , ROCSIL ® FOAM hardens in approximately five minutes .
Prior to the introduction of ROCSIL ® FOAM , foaming cement type products were used for the recovery work . The phenolic foam material is far superior to foaming cement on many critical areas such as faster application rate , improved safety , higher foaming ratios and reduced shuttering to contain the fill material .
The solution has been very successful in Australia where Mastermyne company Wilson MIning through their technology partner Weber Mining identified the benefits of ROCSIL ® FOAM in early 2000 and embarked on an extensive research and development program to introduce the product to Australia with now thousands of use cases .
ROCSIL ® FOAM is a LOBA ( Arnsberg ) approved product and has effectively eliminated foaming cements for cavity filling in Australian underground coal mining . ROCSIL ® FOAM can also be used in a wide variety of applications beyond just cavity filling . This includes sealing underground heatings and mine fires , coal rib support , and surface subsidence crack repairs . the customer a safe and efficient mining operation . But in damp and wet areas , shotcrete may be difficult to apply where fall out can occur due to the shotcrete not bonding to the wet substrate . Additionally , when shotcrete is applied over damp or wet areas water usually penetrates through the shotcrete and then onto the roads . The water damage on the roads can get very costly for the maintenance spent on the road as well as the damage caused to the equipment .
Master Builders Solutions proposed the addition of MasterLife300D , a crystalline capillary waterproofing admixture , to the shotcrete mix in conjunction with MasterLife SF100 , a dry powdered silica fume . MasterLife300D admixture is an integral crystalline capillary waterproofing admixture for concrete . It is designed for use in above- and below-grade applications and reduces concrete permeability effectively allowing the shotcrete to breathe . By supplementing MasterLife300D with MasterLife SF100 , water penetration , and capillary absorption , is reduced due to the denser matrix structure and self-healing nature
of hairline cracks . Both products are conveniently supplied in water-soluble bags , resulting in easy addition to shotcrete mixes whilst adding synthetic fibers .
A new project saw the addition of the MasterLife 300D by 2 % of weight of cementitious material , and MasterLife SF100 dosed at 20kg per / m 3 . It has been employed to combat weeping / damp troublesome ground conditions with a mining customer in South Australia ( 100 m 3 / week of shotcrete ) plus successfully used with another unnamed hard rock mine customer – 150 m 3 was applied to a geologically challenging area that was a critical infrastructure / transport route .
The MasterLife product family are a range of admixtures that provide resistance to deterioration caused by abrasion , corrosion of steel , alkali silica reaction , sulphate attack , and drying shrinkage cracking . MasterLife 300D works by reducing water penetration whilst allowing the concrete to breathe . It uses a crystalline capillary waterproofing system which effectively seals capillaries and heals hairline cracks to 0.4 mm after the concrete has passed the plastic state . MasterLife SF100 is an admixture which improves the hardened characteristics of concrete in two key ways . Firstly , it is a pozzolan which means that it reacts chemically with concrete to increase the amount of calcium silicate hydrate gel formed , thus improving the strength and impermeability of the concrete . Secondly , MasterLife SF100 is an ultrafine mineral that can physically fill voids between cement particles , therefore making the concrete dense and impermeable .
Customer benefits include a reduction in costs associated with road repairs ; maintenance on equipment reduced ; quality of shotcrete application improved in problematic damp areas ;
Admixtures for shotcrete in wet mine areas
Shotcrete is widely used in hard rock mines for ground support & rock reinforcement , allowing
Shotcrete being applied with Master Builders Solutions MasterLife300D crystalline capillary waterproofing admixture
AUGUST 2022 | International Mining