In addition to incorporating design changes aimed at reducing maintenance costs and improving efficiency, OEMs like Hitachi are refining machine-health predictive analysis capabilities that warn fleet operators in advance of potential equipment problems.

Embedded sensor arrays, constant connectivity and rapid data analysis tools help maintenance organizations examine a machine’s past, understand its present status and look into the future to avoid unplanned downtime

By Russell A. Carter, Contributing Editor

Like many other essential links in the mining chain, the nature of maintenance is changing. Industry-wide, there’s a transition under way, at least philosophically, from conducting maintenance as a primarily reactive, localized nuts-and-bolts, boots-on-the-ground function focused on responding to wear-and-tear damage or sudden equipment failures, to one in which worker and machine connectivity, leverage of IoT capabilities and data analysis are becoming as important as a mechanic having the right wrench at the right time.

Although the industry has steadily expanded its maintenance perspective from time-based methods to more proactive, preventive and predictive strategies, its drive to implement better maintenance planning and performance strategies was kicked into a higher gear in 2020 by the urgent need to deal with severely constrained staffing/scheduling options, global travel restrictions and parts availability concerns related to the COVID-19 pandemic.

The economic pain companies may have endured during this period to inject novel solutions into maintenance planning and performance seems to be a price they’re prepared to pay into the future. A recent report by GlobalData forecasts that interest in improving productivity and reducing downtime will lead to further investment by mining companies in predictive maintenance for both mobile and plant equipment in the next two years. A mine-site survey reveals that while more than three-fourths of surveyed mines have already made at least minor investments in predictive maintenance, 48% of those surveyed expect to either invest in the technology for the first time or invest further in the coming two years.

The report, Global Mine-Site Technology Adoption Survey 2020, noted that across the regions studied, predictive maintenance adoption was highest overall in Australasia, and this region is expected to see the highest levels of investment over the next two years, followed by the Americas. Regardless of where and to what extent companies will invest in maintenance, it seems likely that the structure and strategy of tomorrow’s successful mine maintenance programs will be strongly influenced by several factors, including:

• Improvements in asset design, such as new products, features or capabilities introduced by equipment OEMs, service providers and other industry vendors.

• Advances in technical and practical support offerings, from maintenance planning and analysis software to “smarter” diagnostic equipment and tools.

• Organizational objectives that reflect the evolving role of the maintenance work-force in an increasingly digital world.

Here’s a look at a few recent examples of each.

Komatsu’s new ZJ21 jumbo drill rig and ZB21 bolting rig feature a boom design that permits swapping of a drill feed system for a bolting setup and vice versa. The machines are based on a common platform that optimizes operator familiarity, maintenance efficiency and parts inventory requirements.

1 Rig, 2 Roles

Komatsu’s recently introduced ZB21 underground bolting rig and ZJ21 jumbo drill rig illustrate how OEM design philosophy can concurrently simplify both operational functionality and machine maintenance. Both rigs are based on a common platform: the ZB21 bolter’s inner boom can be swapped out for a drilling feed system, effectively converting it to a jumbo, and vice versa with the ZJ21; its inner boom can be changed out for bolting.

Komatsu pointed out that the common platform approach goes beyond just the attachment: the controls are similar as well. A hydraulic pilot control system with universal bolting and drilling controls simplifies user training and adoption across both models. Platform universality also provides advantages with job site efficiency, leveraging common parts, service and maintenance. Komatsu said it also re-engineered the feed system to enhance maintainability and productivity, with new lightweight polyurethane components added for flexibility. Timing ropes are identical lengths with common part numbers and come with a standard quick-attach feature to make changing the ropes easier in an underground setting.

The polyurethane hose drum is bearingless and the graphite-impregnated drum is self-lubricating. Guide strips have been designed with maintenance in mind: they are common from left to right and thicker than those on competing models, but use a slightly softer material to reduce cracking. A single technician with hand tools can change them out, according to the company. Diesel versions of both the ZB21 bolter and the ZJ21 jumbo are available now, while a battery option will be available sometime in 2021.

And in another design breakthrough, Komatsu also plans to introduce two new jumbo boom designs — one with only six hoses that will be commercially available in spring 2021, and a completely hoseless design that handles all fluid and communication transfer within the boom cylinder. The company said its ZJ32Bi jumbo with hose-free booms, which will be introduced at an unspecified later date, eliminates the need to account for hoses in its automation algorithms, and also eliminates wear between the inner and outer boom tubes.

Cat Gears Up

As a maintenance-related benefit for high-volume surface mine operators, Caterpillar incorporated numerous improvements in component design and serviceability features into the latest version of its 90-ton to 120-ton-payload 7495/7495HF electric rope shovels. Among the major changes to the 2021 models are a new propel gear case that is claimed to offer nearly double the life of previous units in extreme operating conditions. The company said precise adjustments to gearing geometry and advancements in tooth hardening have enhanced gear case durability and productivity, resulting in lower total cost of ownership. An ecology drain simplifies oil draining and enables kidney-loop flushing, which reduces abrasion-causing contaminants and oil change frequency.

According to Cat, reconfiguration of the shovels’ crawler carriage now allows drive shaft and tumbler replacement from the outboard side without removing the propel transmission. With this design, thrust loads are evenly distributed on large, tapered roller bearings rather than bronze thrust plates, increasing durability to align with 25,000-hour planned rebuilds, even in harsh environments.

Improvements to the swing mechanism include an upgraded third rail that makes access easier for inspection and retightening and adds support to the thrust rail during operation. New swing girder bushings and girder-to-chassis shim designs offer improved access, reducing service time.

The 7495 and 7495 HF shovels include as standard equipment Cat’s Product Link Elite, which transmits critical machine operating data such as utilization, location and condition via cellular or site internet connection. And to further assist maintenance planning and efficiency, Cat now provides a full bill of materials for each model as an aid for streamlining the parts ordering process and improving parts availability.

Avoiding the Unexpected

In both surface and underground operations, an unexpected failure of a production machine can have mine-wide consequences: a track drill that breaks down in the pit and can’t be moved might delay an important production blast, for example. Underground, getting repair parts to a broken scoop in a distant drift can take precious time, but having that rig fail while tramming in a main passage can clog operations on an entire production level, elevating the problem to a new order of magnitude. Both of those possibilities are strong incentives for mine management to know what condition a machine is in, either in real time or on a rapidly updated basis, and what’s likely to fail first. Vendors such as Sandvik, Epiroc and Hitachi, among others, offer programs that can provide solutions to the problem in various ways.

Sandvik, for example, collaborated with IBM to incorporate IBM’s Watson AI platform into its OptiMine Analytics information management solution, which leverages IoT and AI capabilities to enable real-time decision making, equipment failure forecasting and the ability to predict and simulate various options.

As explained by Sandvik, OptiMine Analytics, through visualization of Overall Equipment Effectiveness (OEE) — a measure, basically, of how much a machine is working effectively within a given time frame — intuitively pinpoints bottlenecks and areas for fleet improvement in terms of mechanical availability, utilization and the quality of its use by operators. From a maintenance standpoint, OptiMine Analytics can inform users about what it expects will occur regarding breakdown of key components throughout an equipment fleet, allowing a mine to efficiently schedule maintenance and optimize mechanical availability.

Meanwhile, Epiroc’s RigScan audit service leverages various technologies to make the equipment audit process faster, less intrusive and more comprehensive, according to the company. Experienced technicians using thermal cameras can find early signs of wear or part stress invisible to the human eye, and unseen internal leaks.

The RigScan audit process is completely digital and conducted on a tablet, allowing the service to incorporate many functions into a single tool that stores images, videos, parts catalogs and equipment manuals. The audit process is tracked internally by the tablet and all data are recorded and fed back into a central server to ensure that nothing is overlooked.

Last year, Hitachi Construction Machinery Co. and its subsidiary, Wenco International Mining Systems, announced ConSite Mine to assist in identifying and resolving equipment problems by remotely monitoring surface mining machinery and applying IoT and AI-based analysis of equipment operational data. Detailed information from predictive alerts is provided on a web-based ConSite Mine dashboard.

In the ConSite Mine system, Wenco provides the IoT digital platform and software technology by which data are collected and displayed on a dashboard customized for each customer, while HCM leverages its expertise on applied analysis technology for structural parts of excavators and haul trucks.

ConSite Mine is an extension of the data-reporting system HCM originally developed for its construction machinery customers. HCM said it currently is piloting the mining-related technology in Australia, Zambia and Indonesia and will use customer feedback from the field sites to refine the system before its commercial release.

Hitachi said ConSite Mine, when released to the market, will offer:

Load Index, an AI technology designed to monitor and predict the possibility of cracks in excavator booms and arms. ConSite Mine collects data from sensors on EX–7 series 190- to 800-ton excavators and analyzes cumulative loads of the boom and arm by utilizing AI and applied analysis technologies.

Pending failure of hydraulic pumps.
ConSite Mine will be able to detect signs that presage failure of hydraulic pumps on EX-7 series excavators and send alerts. HCM said applicable components will be added in the near future.

ConSite Oil, an oil condition-monitoring service initially offered in the construction-machinery version and suitable for application to mining-class equipment. Sensors will monitor an excavator’s hydraulic and lubrication systems, providing data that will enable evaluation of the fluids and associated components.

RCT’s vehicle-mounted Smart Service Monitor alerts operators and maintenance personnel to an upcoming need for service, based on user-selectable parameters.

Getting Smarter

RCT, an Australia-based provider of mine automation and control solutions, introduced the Smart Service Monitor to expand the range of its Muirhead equipment-protection products.

The new expands upon the role of the original Service Monitor — a countdown timer used to indicate when a vehicle is due for service. That device has two stages of warning. The first stage, an amber LED, indicated that the service is due. The second stage, a red flashing LED, indicated that the service is 10% overdue. Both stages also activate an output that can operate a visual and audible alarm. The Smart Service Monitor has four warning stages.

According to RCT, the new monitor expands the capability of the basic device, which only gave an estimate on when a machine needs service, and delivers a more complete information system with data collected from multiple inputs. The new device “allows the monitoring of up to eight measurable components,” RCT Mining and Resources Product Manager Mick Tanner said. “Information is power and having accurate information delivered in an easy and concise manner allows management to ensure machines and their individual components are serviced correctly, therefore significantly increasing machine availability and extending the lifespan of equipment.”

RCT noted that, for example, the monitor could intelligently log engine run hours. By monitoring the RPM, the device can monitor time in idle and time in a work state off the same input. The counter can count up or down depending on what is required.

The monitor’s expanded logging capabilities can help customers ensure that machine servicing is carried out when required to ensure optimal performance. According to the company, monitoring a specific machine component via the Smart Service Monitor only requires a frequency input, PWM input or a simple digital or analog voltage. The device is configured through an internal programming tool, using a WiFi-connected smart device, PC, laptop or cellphone. The connection is password-protected to prevent unauthorized changes or resetting of the device.

RCT also introduced a system designed to monitor operational and service data from an enterprise’s light-vehicle fleet, an asset that generates significant maintenance demands but sometimes gets overlooked as companies focus on opex associated with their large production machines. The EarthTrack Light Vehicle Machine Monitoring delivers machine and operator data from multiple light vehicles across a site.

“It empowers management with the information needed to improve light vehicle operations to lower maintenance costs from damage, reduce unplanned maintenance and deliver an overall safer operation by encouraging better driving habits,” said RCT’s global operations manager, Dave Holman.

“We’ve had reports from some clients that they are seeing about $10K a month in damage due to vehicle abuse and driving conditions and that is on top of the programmed maintenance costs. So, the EarthTrack Light Vehicle Machine Monitoring aims at eliminating these costs,” he said.

The solution is scalable and consists of automated reporting, operator login, pre- and post-start checklists, engine, speed and impact monitoring. The end-user receives an automated summary report on events and violations, early warnings on engine conditions to ensure preventative maintenance can be carried out. Reports can be delivered daily, weekly or monthly depending on preference.

The system, according to the company, can monitor as many vehicles as required with website access hierarchy. Companies can monitor an entire company fleet based on regions or sites if deployed at multiple locations.

The Human Factor

Futuristic scenarios envision machines diagnosing and repairing themselves, but successful mine maintenance organizations will always need a human presence, including a workforce organized and trained to accommodate rapid technological advances.

For example, the role of maintenance managers could change significantly as companies eventually transition to AI-supported prescriptive maintenance methods in which the AI platform would not only monitor and recommend an overhaul for a pump based on temperature and vibration readings, but would also initiate a work order to authorize the repair and then oversee the workflow.

Maintenance teams might comprise a variety of specialists ranging from on-the-spot repair technicians — the “first responders” — to 3D printing specialists trained in industrial design and rapid parts production. As mine equipment design trends move increasingly toward modular design concepts, a core of highly skilled maintenance technicians might be supported by a growing number of generalist workers qualified to perform “plug and play” repairs and tasks of a general nature.

In the current environment, the pandemic-induced inability to allow maintenance teams and specialists to travel freely to mine sites as needed has increased focus on the use of mixed-reality technologies that allow off-site engineering and maintenance teams to observe and instruct on-site crews during equipment installations, repairs and inspections. Travel restrictions prompted BHP, for example, to initiate a program in mid-2020 it calls Remote In, Remote Out (RiRo) for maintenance support at its Western Australia Iron Ore operations.

The core of the program involves an expedited collaboration with Microsoft to outfit mine maintenance workers with the HoloLens 2 — a head-mounted computer with a see-through display running Microsoft’s Dynamics 365 Remote Assist service, which allows off-site supervisory personnel or consultants to immediately see what on-site workers can see, send needed documentation, videos and schematics on the fly, and use digital ink and arrows to annotate real things in the physical world in order to help complete tasks and inspections on remote sites.

In a similar vein, last November, Hexagon’s PPM division announced it was continuing to advance development of interoperability between its Xalt Connected Worker solution and RealWear’s HMT family of wearable, hands-free devices.

Hexagon’s Xalt | Mobility is a cloud-based enterprise software platform designed to allow users to quickly build robust mobile workflows to solve daily challenges. Its technology connects with a customer’s existing enterprise applications, systems and sensors providing front-line workers with necessary data from a single app. Through this approach, said Hexagon, maintenance teams can have real-time access to current work orders, maintenance history, associated engineering documentation, manufacturers’ schematics, permits, safety documentation and best practices. Data integrity, smoother operations and dramatically reduced administration costs are ensured with low initial overhead, according to the company.

RealWear’s voice-enabled headset solutions allow workers to remotely perform live inspections via two-way video as supervisors watch on a laptop.

This approach to maintenance-related digital workflows is designed to optimize a technician’s “time on tool,” according to Hexagon, and improve important metrics such as Mean Time to Repair (MTTR), First Time Fix Rates (FTFR) and overall reliability.