GET-ing to the Point
Ground engaging tools protect earthmover bucket and blade edges, and anti-wear plates and panels serve as sacrificial barriers against premature wear damage in a wide range of mine and plant applications. New materials and designs mean they’ll be around for longer tours of duty.
By Russell A. Carter, Contributing Editor
Even so, omnipresence is perhaps the only constant characteristic actually associated with wear. There are no universal remedies that solve all wear problems, and even the same anti-wear product used in identical equipment setups might not be appropriate at different locations because of variances in environment, rock properties or installation practices. This makes it hard for both vendors and users to accurately predict what product will work best without thorough, time-consuming field testing, which can lead to even more questions, such as how long it should take to collect meaningful data or whether the right metrics are being measured.
Variability also comes into play from the wide array of designs, material choices and price-versus-cost options that a potential customer encounters when shopping for wear-resistant products. Yet, whether the search is for longer-lasting GET (ground engaging tools) to protect an earthmover’s bucket or blade, hardened steel plate to armor a haul-truck body or sturdy synthetic lining to guard chute walls against impact, the process can be condensed down to a simple concept: it’s a battle to control critical surfaces.
On the Edge
As the first earthmover components to contact ore in the mining process, GET are literally the tip of the spear in this fight. Tasked with protecting structural surfaces of the bucket or blade from damage or premature failure due to wear, GET generally must be tough yet hard, substantial yet not exceptionally heavy, and fastened securely without being overly difficult to remove and replace. They can be forged, cast or fabricated from a variety of alloy steels — with prices that reflect their materials and manufacturing cost, and they often play a significant role in the opex and service life of the machine they’re attached to by helping the operator dig more efficiently, avoiding unnecessary stress on bucket, blade, boom, linkage or hydraulic systems.
Choosing an optimal GET system for a particular type of machine and location can involve selecting from a large universe of GET products with similar specs, common or unique fastening systems and prices ranging from dirt cheap to thousands of dollars per item. But what’s the best first step toward realizing maximum value from GET products? It could be just properly managing the system you currently have, according to most GET experts.
“Proactive GET inspection and maintenance is critical to reduce the risk of component loss or breakage and minimize the risk of loss or over-wear contributing to damage to permanent or semi-permanent structural components on the bucket,” said Casey Springer, global product manager, mining expendables, Weir ESCO. “For instance, failure to inspect teeth or intentionally running GET beyond its useful life could lead to wear-through to the adapter nose or lip itself. Damage to these structural elements can create fit and reliability concerns, which can in turn drive a need for unplanned maintenance and equipment downtime to execute a repair or replacement. The cost of lost production and increased maintenance typically exceeds the minimal savings in GET spend that come from running components beyond the end of their useful life.”
It’s impossible to know the number of times a broken GET component has caused a crusher shutdown at mines around the world, or to estimate the productivity losses arising from associated problems resulting from lapses in GET management and inspection. However, there are systems available that are capable of warning operators of broken or missing GET in time to prevent crusher mishaps. The newest of these are also designed to tap into IIoT and other digital technologies to provide up-to-date productivity information based on real-time analysis and reporting.
For example, Springer pointed out that ESCO’s GET Detect system can serve as an added layer of protection for the mine site by quickly detecting loss events. This not only helps reduce damage to any structural components that may be exposed following a loss, but it also provides information needed to quickly isolate a lost component and prevent it from causing significant damage downstream. GET Detect provides real-time feedback of a loss event so the mine can take immediate action. It also helps collect utilization and performance data at the bucket and tooth position level that can be used to better optimize maintenance programs and even develop predictive maintenance models.
Sensors are integrated into each Nemisys point and shroud to eliminate additional handling or installation requirements. Sensors are powered by a self-contained battery that will last the life of each component. These sensors can be removed at the end of the tooth or shroud life for recycling.
ESCO also offers a dedicated customer portal that provides a consolidated view of all operating GET Detect systems installed at the mine site. The portal can be accessed from any web browser by registered and authorized users at multiple locations. The GET Detect portal also provides weekly summary and GET performance reports that are a valuable resource to help with planning maintenance, improve productivity and manage total cost of ownership. • Overall bucket utilization for a given week; • Detect system performance and health; • Bucket performance for each day; • GET performance by location; • GET utilization hours.
CR Mining (formerly CQMS Razer), an Australian company that acquired the underground GET business assets of Keech Castings, another Australian company, in mid-2020 as a move to broaden its GET technology portfolio, also bought GET Trakka, an Australian business that developed a sensor-based GET loss detection system.
The system employs rugged, compact RFID tags that are embedded in a small recess inside GET. These collect real-time digging activity information and wirelessly transmit it to a receiver onboard the excavator. Upon getting a breakage indication, the receiver immediately triggers an alarm module in the cab or operations control center, or both. Broken components continue to transmit a unique signal, enabling rapid location with portable readers.
The sensor network also captures digging and haulage data, which can be used by the company’s Productivity Plus program to convert data into actionable information for reporting mine performance metrics.
Expanding the Range
With more than 700 machine installations worldwide, Weir ESCO’s Nemisys GET system is one of the most popular product lines of its type among mining customers, and the company said it spent the last few years expanding the line to address all mining machine classes. The initial Nemisys offering targeted large mining excavators and draglines, and the system is now available for cable shovels, wheel loaders and less than 250-ton plate lip excavators.
ESCO’s Springer explained that each machine class-specific system features unique elements to maximize its effectiveness and to address pain points found in competitor systems. For example, in the case of the Nemisys system for plate lip hydraulic excavators, advanced metallurgy and tooth design are combined with a unique adapter wear cap design that significantly reduces adapter leg wear, which, in turn, extends the life of these weld-on adapters and minimizes maintenance costs and equipment downtime.
The Nemisys system for wheel loaders, according to Springer, delivers significantly longer lasting teeth — in some applications, more than a threefold increase in wear life vs. OEM systems — and supplements that with optimized shroud designs that address retention, ease of removal and safety concerns that plagued OEM systems. The system also retains the option for mechanically attached adapters, which can be a significant benefit in certain applications where the risk of adapter breakage is greater. The mechanical adapters eliminate the need to perform any hot work associated with adapter removal and reinstallation, significantly reducing maintenance costs, equipment downtime and potential employee exposure.
Two Komatsu-owned companies — Norway-based KVX and Hensley Industries in Dallas, Texas — recently highlighted additions to their GET lines. Hensley’s GET offerings range from the budget-priced Dura DRP line up to its XS2 extreme-strength tooth system for 75-ton loaders and 80-ton-class and above excavators. KVX introduced the E2 tooth system, a line designed for up to midrange excavators that carries over much of the same technology used by KVX in its popular bolt-on adapterless tooth system.
KVX said its specialized bolting technology enables secure attachment of E2 components without welding, thus saving the bucket lip from potential heat-induced cracking over its service life, and eliminating downtime associated with welding and welding-related problems. Additional advantages of the E2 system come from use of a high toughness-rated adapter. The nose of the adapter is now better matched to the hardness of the replaceable tips and is more resistant to wear and deformation from the tooth tips and contamination between adapter and tips, according to the company. Adapters are bolted to the outside of the bucket, providing protection to the lip and bucket floor while leaving the bucket interior smooth and unobstructed to enhance optimal material flow.
Hensley’s GETPro tooth system, displayed at the CONEXPO 2020 trade show, features what is described as an intuitive, foolproof locking design that can be performed by a single worker with a wrench. The system is claimed to offer better adapter nose to tooth fit, and the strength of the adapter nose has been increased by up to 10%. Overall, the GETPro design features 15% more tooth wear material, and wear indicators have been added to assist in GET management.
Weight is often a concern in GET applications, both from payload-reduction and worker-safety perspectives (see sidebar), and for that reason, Hensley and other major GET suppliers stamp item weight on larger GET components. It’s viewed by some customers as an indication of value and wear life, but as ESCO’s Springer explained, component weight by itself is not the supreme criteria for achieving good GET life. “The over-simplification of GET selection can adversely affect system performance and machine productivity. Focusing on point weight, for instance, as a proxy for wear life can not only fail to deliver the expected wear-life improvement as not all wear material is created equal, but the unoptimized addition of wear material can also lead to blunt tooth wear profiles that inhibit penetration and can adversely affect dig cycle times and machine productivity.
“Additionally,” Springer continued, “evaluations of GET systems based on unit price seldom deliver the desired results as any unit price-driven savings will almost always be offset by increased consumption of inferior GET and/or the lost productivity that comes from more frequent maintenance events and unplanned equipment downtime.”
Buckets Underground: Bolting vs. Welding?
Replacing buckets and GET is a normal part of any operation but, as Caterpillar pointed out, underground mines with limited access points and long travel distances from the portal to maintenance areas often find it hard or impossible to bring in assembled, ready-to-install buckets. Instead, mines often have buckets delivered in pieces, which are then welded together underground. While this method solves the problem of getting the bucket where it’s needed, it comes with drawbacks. Welding takes time, skilled labor, and specialized equipment and consumables.
Cat announced last year it also had developed a new Durilock Lip Shroud System for underground loader buckets. The integrated bucket system features hammerless installation and maintenance-free GET retention with elastomer compression retainers. According to the company, the Durilock system delivers 50% faster installation and removal of GET compared to legacy, mechanically attached systems, and, because there is no need to re-torque bolts periodically, maintenance time for GET is reduced by more than 50%. Additionally, integral corner guards extend bucket in-service time by about 30%.
The Durilock system has three shroud styles: The D50S Standard is a traditional wedge shape used in most production and development applications. The D50A Abrasion has a contoured design and repositions more material on the shroud base, and the D50P Penetration has less leading-edge material to deliver easier penetration in dense material.
The lip assembly provides the mounting surfaces for the shrouds and corner protectors, which balance corner and center station wear rates. Cast corners are welded to the base edge assembly to create the lip assembly. The corners incorporate a stepped design that eliminates corner shroud torsional loads. According to Cat, the integral corner design boosts corner life by 15% and improves penetration compared to systems that experience corner erosion and shortened bucket life due to corner rounding.
A Quicker Route to Advanced Alloys
Many mines choose to have GET components reinforced with hardfacing material. Some order hardened GETs directly from the OEM and others send components out to hardfacing services. Either approach involves increased costs — for purchase expense or logistical arrangements. This is an area in which the use of “big data” analysis methods has the potential to offer benefits for both vendors and customers. As an example, hardfacing materials recently developed by surface solutions provider Oerlikon Metco using its Scoperta Computational Rapid Alloy Design Process are claimed to have comparable abrasion resistance to tungsten carbide with the impact strength of manganese steel, while eliminating the need for specialized welding capabilities for proper application.
In a recent webinar, Oerlikon Metco’s mining-applications manager explained how the Scoperta process provides advantages in the design of new industrial materials such as its 8247 hardfacing wire. Benefits include: 1) a rapid process that allows the company to formulate new solutions in months instead of years; 2) development of innovative material compositions with unique service characteristics to solve application issues that conventional alloy development process cannot; and 3) formulations designed specifically for surface applications —avoiding a common problem in that while a bulk alloy may have the desired wear, corrosion or other characteristics, those properties often don’t carry over completely when the same alloy is used as a surface solution.
“These new material technologies provide significant improvement in component operational performance and are the future of maintaining plant sustainability,” said Adolfo Castells, global product portfolio manager for hardfacing products at Oerlikon Metco. “Metco 8247 is an iron-based composite wire for use as a non-cracking hardfacing material applied to bucket teeth. We discovered that components hardfaced with Metco 8247 showed an increased component life of 200% to 400%. Teeth lasted approximately 1.5 to 2 times longer than unhardfaced teeth, leading to less frequent change-outs of components, reducing machine downtime and lowering labor costs. The use of a wear-resistant, non-cracking hardface materials such as Metco 8247 can eliminate GET failure while maintaining the designed geometry of the GET.”
According to the company, 8247 wire only requires conventional welding (GMAW or MIG) on Q & T steels and can be applied in much thinner overlays that provide significantly longer service life when compared with tungsten carbide hardfacing. The company also offers another Fe-based hardfacing material, 8223, for use on GET components made from manganese steel.
Making a Trade
When the word “tradeoff” appears in a product evaluation, it usually means giving up something to gain something else — possibly cost vs. reliability, weight vs. strength or convenience vs. functionality, to name a few. When it comes to the choice of abrasion-resistant steel products for mining applications, Swedish steelmaker SSAB believes it can offer a win-win tradeoff proposition involving its Hardox wear steel plate that enables customers to choose a desired advantage without incurring a corresponding penalty.
Hardox 500 Tuf is a fairly recent addition to the family of Hardox wear plate products originally introduced by SSAB in the 1970s. SSAB’s technical development manager, Maurice Picard, outlined the technical and practical advantages. “Hardox 500 Tuf enables users to replace thicker and lower hardness steels that are often harder-to-handle in the workshop,” Picard explained. “It can be installed in thinner sheets when compared with Hardox 450 for example, and Hardox 500 Tuf offers a Charpy impact toughness of 33 ft-lb at -40° F, comparable to that of Hardox 450 (37ft-lb). This rating, he noted, provides very good cracking resistance in extremely cold environments.”
Picard also noted that Hardox 500 Tuf offers advantages to OEMs and service facilities. Because it can be substituted for thicker steel plating, a shop won’t need the high press brake machine capacity required to work on thicker sheets, and 500 Tuf requires a much lower welding preheat temperature (167°F for 5/8-in. plate) than either Hardox 450 (257°F for 1-in. plate) or Hardox 500 (347°F for ½-in.). For plates less than 5/8 in. thick, Hardox 500 Tuf requires no preheating at all.
As an example, a team from Car- Wil, a Hardox Wearparts center in Nevada, worked with engineers at SSAB’s Knowledge Service Center to develop a haul-truck body liner design that signifi- cantly reduced liner-package weight and increased overall wear life. Upgrading from standard thickness abrasion-resistant steel to thinner liners of Hardox wear plate allowed CarWil to design a weight-efficient package that offers the highest wear resistance in the right places.
CarWil used ½-in.-thick Hardox 500 Tuf in the body liner’s main flooring sections, replacing a 5/8-in.-thick liner of standard AR. For the tail section, where the most damaging sliding wear occurs, they specified ½-in.-thick Hardox 550. These changes more than doubled the liner’s wear life and reduced the weight by 20%, according to the company, which translates into a higher capacity potential and lower fuel costs per trip.
“That means one less liner replacement over the lifespan of a heavy hauler in an aggressive mining operation or a $75K cycle savings,” said Shane Havens, CarWil general manager.
Austin Engineering, which engineers and manufactures various types of mining equipment including surface and underground haul truck bodies, began using Hardox plate in its body designs in the 1980s, employing Hardox 400 and 450 as a means to cut dead weight and increase payload capacity. Austin has turned to Hardox 500 Tuf as the next step in weight-saving design.
Austin formerly used 1-in. thick Hardox 450 to create custom body designs, but when it switched to 3/4-in. Hardox 500 Tuf, it was able to reduce component weight by 25%, according to SSAB. “With these type of projects, it is a matter of going through every little detail to make sure that the result is as expected. We offer many tools and expertise to assist our customers. It is not only looking at increased service life or reduced weight, but also examining all steps when it comes to welding, supply of test material or stress calculations that needs to be carefully investigated before starting serial production,” said Jonas Allebert, wear specialist at SSAB.
Saving Time, Trouble and Money
The expansion of market-ready wear material choices and component design has opened the door to a wider possibility of savings for mining customers. SSAB’s Picard noted that the possible weight-saving benefits of Hardox 500 Tuf isn’t limited to truck bodies. It can be used in excavator and loader buckets to reduce overall bucket weight and increase payload while reducing the need to bolt or weld additional wear components to the bucket. This can provide easier digging and tangible opex savings in fuel and maintenance. SSAB pointed to a real-life example of a 5.2-yd3 bucket mounted on a 60-ton excavator: the use of Hardox 500 Tuf resulted in a 14% weight reduction overall when compared with conventional steel construction, a 10% increase in steel plate service life and an approximate 3% savings in fuel amounting to 634 gal/year.
Weir ESCO’s Springer said the company had seen a high level of interest in its Nemisys cable shovel system by North American iron ore producers. Multiple customers in that area have opted to convert their entire cable shovel fleets over to Nemisys thanks in part, said Springer, to the system’s ability to deliver a cost-perton that was as much as 15% lower than the system they’d run previously.
“Nemisys systems for cable shovels have proven to be successful outside of iron ore as well, having delivered comparable wear life and cost-per-ton results in copper mines in Peru, a gold mine in Australia and coal mines in Western Canada, to name a few,” he continued.
“Similarly, Nemisys for wheel loaders has also delivered favorable results in hard rock applications. A gold mine in North America recently trialed Nemisys loader points and saw wear life extended by more than three times vs. OEM GET (185 hours per tooth increased to 685 hours per tooth). This extended wear life helped the mine reduce its annual GET spend and improve site safety by significantly reducing employee exposure through fewer GET changes and maintenance events. Additionally, the extended wear life yielded sustainability improvements for the mine as the reduced tooth consumption translated to a savings of more than 39 tons of steel produced and 16 tons of material that must be recycled at end-of-life on an annualized basis.”
Ceramic Panels Extend Service Life
FLSmidth introduced its FerroCer ceramic wear panel line in 2017, offering it as a 44-mm-thick but lighter, easier-to-handle yet durable alternative to conventional metallic anti-wear liners. They followed up with FerroCer 22 two years later — a thinner panel by half, designed for use in applications that need or can benefit from weight savings. The company recently reported a success story involving FerroCer 22 at a major iron ore producer in Western Australia.
“Thanks to our close working relationship with the mining company, encompassing an installed base of more than 50 stockyard machines, we were invited to inspect the worn buckets and propose a solution. After visiting various sites, we suggested adding FerroCer wear panels to the areas of high wear,” Bozward said.
Each FerroCer panel comprises a set of abrasion-resistant ceramic inserts enclosed in a matrix of malleable steel. The matrix ensures only the top surface of the inserts is exposed to material impact. The sides of the inserts are tapered within the matrix, keeping the inserts in place and preventing material particles and fluids from damaging the panels.
To test the ability of FerroCer to meet the mining company’s objectives, FLS supplied three buckets — two with the FerroCer panels and one with the existing design as a control. The upgraded panels also included WearMax epoxy ceramic coating, applied inside the bucket around the FerroCer panels, as well as to the outside of the bucket to protect the FerroCer panel hold-down fixings. “We monitored and documented bucket wear at each shutdown interval. Although in the end, two inspections were missed: one due to disruption caused by a cyclone, and one due to COVID-19 travel restrictions,” Bozward said. “In doing so, we had to work closely with the site team to coordinate our inspections during the shutdowns to ensure we could gain access to the buckets.
The upgraded buckets were still in service after 48 weeks — the service life of the existing solution; at 60 weeks, the target set by the mining company; and remained in operation as the mine approached a scheduled shutdown at 94 weeks. This performance, Bozward reported, almost doubled the service life of the existing buckets, extending it by four shutdown cycles, and discussions were ongoing to push the buckets past 94 weeks to the 106-week service point and beyond.