GROUND SUPPORT
The MacLean 985 Abi-Bolter product development process is moving through its final stages of systems testing at the company ’ s underground Research & Training Facility in Sudbury , Ontario
MacLean focus on product development in the areas of electrification , automation , and digitalisation is in direct response to the industry ’ s greatest challenges and opportunities this century . We ’ re on the innovation frontlines with our customers .”
Epiroc progresses its autobolting with SDAs & pumpable resin
At the Epiroc World Expo 2023 in Orebro , Sweden , attended by IM , Peter Bray , Epiroc Global Product Manager – Rock Reinforcement Equipment presented the latest Boltec E10 S ABR – the latest and most advanced incarnation of its Boltec E10 and M10 models first introduced in 2021 , which introduced previously unavailable autonomous functionality to full mechanised bolting . In this case the ABR stands for Auto Bolt Reload .
Bray stated : “ Those of you that have seen a Boltec before – there are a lot of similarities but also some important differences in the bolter carrier magazine . We have the ability to have 44 bolts in the magazine , using an overhead gantry to pick up four bolts at a time and drops them into the feed magazine where a total of eight bolts can be held .”
The overall design of this set-up began in 2016 , with the first proof of concept machine delivered to LKAB ’ s Kiruna iron ore mine in northern Sweden in early 2020 . “ This was originally just a six month field trial but since that was completed successfully they decided to continue to rent that machine , which is still in operation today more than three years later .”
From that work , Bray said it has seen that the reloading system works very well and is very reliable . “ The heart and soul of the machine is the bolts themselves – self drilling anchors – used with a pumpable resin .” The back of the machine has two tanks – one white , one black . These contain the two main components of a polyurea silicate resin – Epiroc uses Weber Mining ’ s POTENTIA ® THIXO – and it isn ’ t until the components are mixed together that the chemical reaction actually starts .
There are two individual gear pumps that
Deep mine equipment cooling
Excessive heat is an issue for mechanised ground support equipment working in deep mines . UKbased EJ Bowman has been cooling hydraulically powered machinery and equipment for over 60 years and says it is renowned for the quality and efficiency of its hydraulic oil coolers , many of which are used in deep mining . Excessive heat in the hydraulic oil will reduce equipment performance and may lead to component failure , so maintaining the correct temperature is extremely important . All oil coolers are precision made in the UK using high quality materials , enabling them to operate reliably in the most challenging conditions . Most models are suitable for water and oil pressures of up to 35 bar while the shell and tube construction is suitable for using both clean and harsh cooling water . The fully floating tube stack minimises thermal stresses and aids removal for cleaning . SAE hydraulic oil flange connections are offered on larger models while tube stack materials and construction options are available to suit mine water conditions – including high salt content . The coolers also have a large heat exchange surface area to volume ratio that gives them high thermal efficiency . Bowman supplies many of the world ' s leading OEMs in mining while its heat exchangers and oil coolers are also available for retrofit to virtually any mining machinery or equipment to overcome cooling problems in the field .
pump the components via hoses to the mixing point , with the pumps controlling the flow and pumping pressure at all times – and they are controlled via the Boltec ’ s Rig Control System ( RCS ). If anything is out of the set parameters , pumping can be stopped immediately . The components are mixed using static mixers that fold them together over and over again until you have a complete mix . The mixed resin is pumped via an injection cup that is held against the base of the SDA bolt with approximately 500 kg of feed force to ensure a good injection seal as well as pushing the bolt and plate hard up against the rock surface . The mixed resin flows up inside the bolt via the flushing hole and then out through the drill bit to fill the bolt hole from the top down . When resin is seen coming out from behind the plate , it is an indication that all cracks and voids inside the bolt hole are filled and that the bolt is fully encapsulated .
There is one extra element on this machine which makes it all repeatable . “ After every injection sequence , we flush the static mixer element with biodegradable grease . If this was not done , the remaining resin inside the mixer element would harden resulting in more or less a one use item . The flushing grease is very effective , with up to 300-500 injection sequences before we need to change out the mixer element .”
The machine at the Epiroc World Expo 2023 was a new prototype bound for Boliden ’ s Garpenberg Mine , Sweden . “ What we are going to be doing there is building on what we already know works – the mechanised bolt reloading system . We also did a field trial in 2022 at Boliden ’ s Kristineberg Mine which was primarily to test the new machine software for automated drilling and installation of bolts . Now we will combine the two together for operation of the ABR at Garpenberg starting in August 2023 .”
The machine will be used for autobolting . It also has the same teleremote cameras that are used on Epiroc Simba production drills . Bray concludes : “ When it comes to the automation of bolting – we have had the technical ability to do it for many years – the first fully autonomous Simba was running in the early 1990s as well as the first Simba teleremote control system . Boomers have had the ability to conduct automated face drilling since the mid-1990s . The bolts themselves where the remaining missing piece . Because when we are installing bolts , especially in bad ground conditions , if you are trying to shoot resin cartridges into a partially broken hole with some smaller rocks inside , the cartridge gets stopped so you lose the ability to autonomously bolt . Misalignment if you are trying to bolt through mesh is another problem . But by using a self drilling anchor or SDA , the bolt is the drill string – you drill it in and inject it
44 International Mining | AUGUST 2023