Spotlight Feature Articles GROUND SUPPORT & ROCK REINFORCEMENT | Page 9

GROUND SUPPORT & ROCK REINFORCEMENT
8 ° oscillation and a robust manipulator with 8.5 m vertical and 9 m horizontal spraying reach at 4 m distance from the working face . The BIS20 is 10.35 m long , 2.3 m wide and 2.55 m high . For dry-mix applications the BKS9 is available with 7 to 9 m 3 / h concrete spraying capacity .
MAPEI Underground Technology customised solutions
MAPEI says its Underground Technology Team ( UTT ) offers a comprehensive range of chemical , mineral , and cementitious grout options to help its underground mining customers solve challenging problems in ground consolidation , soil stabilisation , and anchoring . Chemical injection resins include Polyurethane ( PUR ) and Polyurea Silicate ( PUS ) variations for quick and permanent stabilisation applications . Bill Cheatham , Business Development Leader , MAPEI UTT North America told IM : “ Filling cavities and voids is a common challenge in mining and underground construction . When Part-A and Part- B of a chemical grout are combined , there is an exothermic reaction during which the product turns into a foaming adhesive mass that will stop water , fill voids , and glue unstable rock into a solid mass . With our expertise and years of experience , we assist our clients in choosing the right technologies for specific uses .”
The heat reaction delta is drastically different between PUR and PUS products , with the PURs being the hotter of the two . “ In our application experience , we have learned that when filling voids in coal mines , MAPEI UTT ’ s SilicaJet EXP NA ( North America ), is the ideal product , because it expands 20 to 40 times but produces around half the heat as other PUR products on the market . PURs do have a critical role to play in underground mining , and MAPEI UTT ’ s FoamJet T NA has been a work horse when it comes to stopping water , consolidating dikes or filling voids created by naturally forming vugs or faults .”
MAPEI UTT ’ s solution for anchoring cable bolts is found in a PUS technology , SilicaJet ANK NA . This product does not expand and has a short reaction period , making it ideal for use when installing cable bolts . SilicaJet ANK obtains all its strength in the first hour after installation ; therefore , miners have been able to get underneath installed cable bolts in a matter of hours , instead of days . “ This reduces the amount of downtime – and lost revenue – for the mine . Our miners have also found that SilicaJet ANK NA can be pumped into hollow bar . Hollow bar is usually filled with pumpable cementitious grouts .”
Cheatham says , “ Our customers have been coming to us looking for an alternative to sausage-style polyester resin cartridges simply because the cartridges are becoming increasingly tough to find . The issues with the global supply chain have not been kind to
PAUS ’ s perfect match for underground concrete
PAUS says its UNI 50 series offers a perfect match in combination of concrete mixer and shotcrete
solutions . “ If high hardened concrete qualities are required and high outputs are demanded , then the UNI 50-3 BS as a wet shotcrete vehicle is exactly the right vehicle for your tasks . With more than 20 m 3 / h spraying capacity , the concrete pump of the Uni 50-3 BS fulfils the highest demands and has an extremely high area coverage with small vehicle dimensions .” With precise measuring technology , the PAUS UNI 50-3 BS allows control of the amount of water and aggregate added , “ promising excellent concrete spraying results with the highest durability properties .” The UNI 50- 3 BS is also available as an electric version for the sustainable shotcrete process . To support the shotcrete sprayer , and also based on the UNI 50 ( or UNI 40 for smaller headings ), PAUS also offers different possibilities for the transport of concrete in mining and tunnelling . “ Whether as free-fall or transport mixer – our vehicles convince by high drive power and high driving comfort at low operating costs . PAUS transport mixers are available with a mixer volume of 2.5-7.5 m and thus we can offer suitable vehicles for almost every requirement .”
At the bauma 2022 show , PAUS is set to launch the UNI 50-5 BM-TM concrete mixer , which is optimised for underground mining operations . With a 7.5 m 3 drum PAUS says it is the ideal mixer for small to medium sized diameters in mining and tunnelling . It also features the PAUS MinCa suspension system , which has already proven itself many times over in mines . Loaded or empty , the front axle suspension gives the UNI 50-5 BM-TM ideal ground contact - even at high speeds on poor road surfaces . Paus delivers the UNI 50-5 with an engine power of up to 173 kW with Deutz or Mercedes Benz engines and further engine variants on request ex-works Emsbüren . Long distances , also with up to 35 % gradient , to the operating site and back again can be easily managed by the vehicle with installed APC transmission control ( automatic gear shift ). The concrete mixer with a total weight of 32 t can also be optionally equipped with Stage V engines . These engines have lower emissions and thus contribute to reduced ventilation requirements in the mine . The basic configuration and the improved cooling concept are designed for operation in the environmental temperature range from -20 ° C to + 40 ° C . The vehicle safety system , which is designed to operate in mines , includes integrated fire protection solutions , hydraulics that mainly use pipes and only a few flexible hoses , an interference-resistant electrical system and material thicknesses that are designed for demanding operating conditions and high corrosion , heat and water resistance .
polyester resin , some key ingredients are very difficult to source right now . Miners can be very risk adverse . Silicajet ANK NA also ensures that the components are completely and correctly mixed before they ’ re injected , while with sausage cartridges the quality of the mix is heavily dependent on the rod and the expertise of the operator . Bad mixing can lead to groundwater pollution since the single components can dissolve in it when left out of the reaction due to bad mixing .”
He adds : “ We spent two years testing our chemical grout technologies with numerous stakeholders . In doing so , we have validated that our chemical grout technologies are not only useful , but better in many ways than traditional competitive technologies .”
MAPEI UTT also offers its clients a complete line of cementitious grouts . Stabilcem T and Stabilcem AG are bagged grouts designed to be used with anchor bolts and cable bolts for the stoppage of water ingress or stabilising weak ground . “ Our clients have also had success with our microfine cement line , Microcem 8000 and Microcem 12000 . The Blaine fineness is measured in terms of the specific area of cement expressed as total surface area in square
centimetres per gram . Microcem 8000 has a cement Blaine of 8000 and Microcem 12000 has
a cement Blaine of 12000 . All of MAPEI UTT ’ s cementitious grouts have excellent pot times and the incredible high early strengths .” IM
AUGUST 2022 | International Mining