HIGH PROFILE
Fredrik Björk , Product Manager for Top Hammer Surface Tools ; Right : Robert Grandin , Product Manager for Top Hammer Underground Tools
automation in the next four to five years .” Some of the plus points from the previously available Sandvik Alpha™ 330 have been carried forward – the short thread and the guide behind it . The new Alpha product – Sandvik Alpha™ 340 – began rollout in the market in late 2022 . It is applicable to rod lengths of 2.4-6.4 m ; bit sizes of 43-76 mm ; and reaming bit sizes of 102-127 mm . Then you have Sandvik Alpha™ 360 which has the same design changes but is larger – it combines a robust short thread with a sturdy guide system . This increases resistance to bending stresses , improves bit guidance and ensures effective energy transfer .
On market rollout he commented : “ Considering that we are a major player and that Sandvik
Alpha™ 330 has been our flagship product pretty much sold everywhere , it has been and is a huge project to upgrade all of these customers to the new concept . And because of the degree of higher performance and service life , Sandvik Alpha™ 330 is being completely replaced . We started this process in November 2022 and by June 2023 had reached halfway – to date this has nearly been completed . All these customers are already implementing it at site level . And while we expected some teething issues , so far we have actually had none , which is quite something for such a new product and solution . We have had at least a 30 % longer service life versus competitor solutions and on average 15-20 % versus Sandvik Alpha™ 330 . Increased service life results in increased productivity and reduced cost per metre advanced ; plus of course we have had much higher customer satisfaction because it is so much easier to use for operators .”
Autobit for the masses
The new thread concept goes hand in hand with improved drill bits . High performance PowerCarbide ® grades are now more widely available in the standard bit assortment , with many bits having received design upgrades with more gauge angles or larger buttons for increased robustness .
But the most significant product here is
Autobit . Brungs : “ Automation is something that everyone is interested in . What we saw was that drilling over shift changes using autonomous drilling technology in medium abrasive ground , that the previous bits were not going to last an entire shift change . This is because the level of wear on the carbide starts to slow down drilling significantly and you need to change the bit . And actually , auto bit changers are not popular with customers as they see it as another machine with fine mechanics they need to maintain underground in often wet and challenging conditions .”
Grandin adds : “ At Sandvik , we said OK , lets develop at bit which you can use for a longer period of time . We engineered the design , looking
at the fundamentals – why do bits wear out , how do they wear and what stops them drilling ? We changed the button design including the geometry around the buttons and not only that but also the carbide grade . In simple terms we delayed all the factors that start to make bit functionality drop off . We also reduced the amount of excess steel that can come into contact with the rock by making the insert protrude more to maximise the length of time carbide is in play . And in other areas we carved out a recess in the steel to enhance this even more .”
Autobit was designed to work with autonomous drilling and this is where it started in the market but in fact it has now been deployed in many non autonomous drilling situations as well simply due to its performance . Grandin
Autobit comes with a new , innovative bit design , which combines a strong gauge row , fully ballistic button profile and carved-out front design continues : “ All the things I have described are pretty attractive in non autonomous as well as autonomous drilling . The design and reduced steel area means you can drill the carbide inserts to near flat and the bit will still work . And we are utilising PowerCarbide ® – while competitors have made investments in PCD technology , it comes with a much higher cost , and our unique carbide grades deliver similar performance because they drill with 30 % higher drill speed . Not only that but PCD as a material does not allow you to do some of the things we have done , notably the greater insert protrusion and aggressive geometry , because by nature PCD is very sensitive to breakages .”
He says the market for Autobit has grown exponentially since Sandvik launched it . “ There is no question it has the potential to become the dominant solution in the market – you could almost rename it The Bit not just Autobit ! There is no real reason to use anything else . We are seeing it for example being used in African mines that have no autonomous drills but appreciate the penetration rate and longer service life .”
In terms of use strategy in those mines that do use autonomous drilling , the idea is that when the shift is over , then you put on a new Autobit for autonomous drilling . Then you regrind it and drill it during the manual drilling shift . The grinding interval declines after several regrinds but that is all relative – the overall life improvement is still very high . This all reflects the fact that many mines operate drilling manually during normal shifts and only use autonomous mode between shifts – they are not running their drills autonomously all the time .
While Autobit was first rolled out for autonomous production ie fan drilling in stopes , in late 2023 , it was also introduced into autonomous development drilling applications .
The power of PowerCarbide ®
We also talked to Petter Bengtsson , Director Marketing & Communications – Rock Tools Division about the important role played by Sandvik ’ s in-house tungsten carbide production facility in Västberga ( which was also visited by IM and will also be the subject of a follow up article ): “ We are really grateful for Västberga and the carbide R & D we have there – without its innovations , the new Autobit design would just not be feasible in harder rocks . The carbide development is really an enabler to us on the rock tools teams . Competitors by comparison have to buy standard carbide products on the open market . New carbide grades are traditionally made by changing the grain size and binder used . You want to achieve maximum hardness along with maximum toughness . We have moved away from the standard XT48 which have similar hardness throughout the body of the insert
MARCH 2024 | International Mining 41