Suppliers hope to give miners options for moving more for less

by jesse morton, technical writer

Powder River Basin (PRB) miner investor reports released this year reveal increasing strip ratio was driving up costs at a few of the mines.

For example, the now-defunct Cloud Peak Energy (CPE) reported in an annual report that higher strip ratios, increasing at a time of “sustained low customer demand,” rendered Cordero Rojo “uneconomic.” In its Q1 2019 report, the company said that, generally speaking, “higher strip ratio” at its mines drove up cost per ton for the period.

Western Fuels Association reported in its annual report that by 2023, the strip ratio at its flagship Dry Fork mine “will have increased by over 40%.” The non-profit reported increasing strip ratio is “a challenge other mines in the PRB have experienced for several years.”

That trend shows up as increase in cost per ton, usually from blowing through more diesel and explosives to access the same seam. CPE, Arch, Peabody and Western Fuels all reported increases in costs per ton at their PRB ops for 2018 or for Q1 2019.

Recent news from suppliers in the space spotlights solutions that speak to the growing need of surface mines to move more for less, and to do it safely. Most of the solutions promoted are now field proven. And what they all have in common is they promise the miner more optionality, allowing the miner to find their own ways to cut costs.

Never Get Bogged Down

Point Lick Energy’s Camel’s Creek site in West Virginia reported it deployed three Volvo A60H 60-ton articulated haulers and a Volvo EC750E excavator to tackle 100-ft-thick overburden. The equipment is moving roughly 2,000 yd3 per day, according to Larry Grogg, general superintendent of the mine.

“We have used 40-ton trucks for reclamation but decided to go with the 60 tons,” Grogg said. “In six months, they have between 2,100 and 6,800 hours on them, and are running at 98% to 99% availability.”

Grogg described the haulers as perfect for the project because initially “we had no rock base and rough weather conditions.”

The trucks “never got bogged down in the mud, they pulled right through,” Grogg said.

They also handled the hills with ease. “Right now our haul road is 2,700 ft with 8% to 10% grades,” Grogg said. With the A60H trucks, when coming downhill, the operators don’t have to use the brakes, he said. “The engine retarder system works great at holding the trucks to a steady speed,” Grogg said. “The operators love them, especially the comfort of the ride and the backup cameras.”

Volvo told Coal Age the A60H is now widely deployed at mine sites in the U.S. similar to Camel’s Creek. The hauler was first released at bauma 2016 and announced at MINExpo later that year. MINExpo proved to be roughly the midpoint of a decade-long uptick in demand for articulated haulers in general, Eric Fatyol, product manager, Volvo Construction Equipment, said.

“By CONEXPO-CON/AGG 2017, we had Tier 4F market-ready A60H units that we began demoing with target customers throughout the United States,” Fatyol said. “From there, the A60H exceeded all expectations for sales in North America, and we’ve had to ramp up production to meet demand. Today, North America is Volvo’s biggest market for the A60H, and about 95% of those customers are using them in mining and aggregate applications.”

The A60H is the largest fully articulated hauler on the market, Fatyol said. Because it can go where rigid trucks can’t, it enables miners to “extend their working season to be year-round and work in all weather conditions, access otherwise inaccessible areas of the mine, and avoid building new haul roads,” he said.

Features include on-board weighing, Hill Assist, the Dump Support System, and the Dynamic Volvo Engine Brake system.

On-board weighing, which is fully automatic, is part of the Haul Assist system and comes standard. Fatyol described it as using load indicator lights to alert both the hauler operator and the excavator operator when the desired load has been reached and when it has been exceeded. “The hauler operator can also see, in real-time, the actual tonnage displayed on the in-cab Contronics display, which also includes a new Econometer feature showing fuel economy in the form of gallon per transported ton, per work cycle for the last 10 cycles,” he said. That data also integrates with Volvo’s telematics system, CareTrack, allowing it to be analyzed in the back office.

Hill Assist holds the truck in place on steep slopes. “The feature automatically activates when arriving at a complete stop on a hill and is disengaged when the operator accelerates,” Fatyol said.

The Dump Support System allows the operator to configure an alert system based on percentage side inclination of the truck. “This feature can be configured three ways: off, on with an alarm, and on with an alarm and a complete bed stop,” Fatyol said.

With the Dynamic Volvo Engine Brake system, the torque and shift points can be adjusted against the load, inclination and rolling resistance. “That improves brake life by reducing the need to use the brake and retarder pedal when going downhill,” Fatyol said. “It also leads to significant increases in max torque.”

Fatyol described the hauler as ideal for miners that want to upgrade from smaller trucks to bigger ones with the benefits that brings, such as increased production and lowered costs, and without many process changes. For example, the A60H puts down ground pressure similar to the A40 or A45 models, he said. “This is why the A60H works so well in less-than-pristine underfoot conditions.”

For another example, for over-the-road transport, the hauler can be moved fully assembled on a beam-style trailer.

The A60H is backed by a lifetime frame and structure warranty, under which the frame and articulation joints are protected for the entirety of the initial period of ownership or for the life of the machine. The company also offers ActiveCare Direct, a machine monitoring service.

“ActiveCare Direct is a pretty dramatic shift in our industry’s approach to telematics,” Fatyol said. Typically telematics entails sending the customer every undiagnosed fault code, burdening the customer with the responsibility to analyze the raw data and determine what steps to take, he said. “Instead, Volvo ActiveCare Direct sends not just the fault code, but also the probable cause, recommended solution and potential consequences of not taking action,” Fatyol added.

The level of interest from customers like Camel’s Creek mine in bigger articulated trucks has Volvo looking at possibly designing a bigger unit than the A60H. For the near term, however, it will likely remain the largest available, Fatyol said. “We’re currently restricted by the capability of tires to handle higher loads in off-road conditions,” he said. “So, until tires advance, we’re likely capped out at 60 tons for articulated haulers.”

Pursue Continuous Improvement

FLANDERS reported in a white paper that field results show a miner who adopted its Freedom Level 3 shovel control system package saw a 24% increase in productivity.

With the system, a lower-performing shovel became one of the highest performing units in the fleet without increased maintenance costs.

Such results are the norm when upgrading a shovel with a Freedom package, company leadership reported. “In mining, the bottom line boils down to producing for the lowest cost-per-ton,” Doug Patterson, global business development director, FLANDERS, said. “By selecting the proper electrical upgrade, not only can productivity increase, but also reliability, which drives maintenance costs down and availability up,” he said. “The total cost of ownership and cost per ton are notably reduced.”

Released in 2012, Freedom, an open architecture platform, centers on shovel control software designed to enable optimized shovel performance. The software leverages a cycle decomposition algorithm that helps determine when certain functionalities should be used. Those functionalities include dig force control, boom jack reduction, and production monitoring.

Dig force control offers assistance in controlling digging motion in the bank, which decreases time spent in the bank and increases boom and gantry life, the company reported.

The boom jack reduction functionality alerts to the early signs of a boom jack event. “Preliminary testing shows a dramatic reduction in the number of Stage 2 boom jack events,” the company reported.

The production monitoring functionality tracks cycle times and truck times, and builds shift time breakouts.

Other functionalities include an auto brake, swing impact detection and control loss detection.

Freedom is offered in three packages that include component changeouts with OEM and aftermarket solutions, such as FLANDERS’ high-performance excavator-duty motors.

With the Freedom Se base package, FLANDERS replaces obsolete shovel control components, such as field drives, with DCS800 hardware and a specialized screen, typically installed in one day.

With the Freedom Si package, analog technology is upgraded to digital, and hardware, software and the control cabinet is replaced.

For both, the Freedom software jibes with existing systems “and provides enhanced troubleshooting capabilities,” the white paper stated.

With the Freedom Level 3 system package, a FLANDERS M21 or F22 crowd motor is deployed. “FLANDERS motors outperform all other competitors by increasing available power significantly within existing frames to increase operating speeds and production volumes,” the white paper states.

Offered with the Freedom Level 3 package is Optimized Bank Performance (OPB), a machine monitoring system that captures and reacts to data from the boom and gantry structure. “This real-time monitoring enables enhanced performance and increased productivity while staying within the machine’s existing OEM limits,” FLANDERS reported. “Using Freedom Level 3, structural abuse to the machine is reduced while hoist power is optimized during a portion of the dig cycle.”

Patterson said OBP goes beyond enhancing baseline production capability. “The inherent operator assist function allows even a newer or mediocre operator to improve his productivity, while still protecting the machine mechanically and structurally,” he said.

Freedom upgrades are proven to up overall performance while contributing to extended longevity of mechanical and structural components, the company reported. “The FLANDERS OBP product relies on continuous structural monitoring through the use of strain gauges in the boom and gantry, as well as torque control for each motion,” Patterson said. “These feedbacks are not just for monitoring but are actually used in the algorithms for adaptive control of each motion. Stress on the shovel is actually decreased.”

After years in the field at mines around the world, the Freedom packages effectively prove that “innovators and those who are passionate for continuous improvement more often outperform the market, no matter what is happening in specific sectors,” Patterson said. “Its proven track record over many years minimizes the natural concern many people might have with trying something new or different.”

Lose Some Weight

Field results from coal mines in Australia prove Columbia Steel’s TwistLink Chain for draglines offers optimal performance while weighing significantly less than standard chain, the company reported. Naturally, going forward TwistLink is expected to see more widespread adoption at sites in North America, Mark Barton, manager, Columbia Steel, told Coal Age.

“Most TwistLink chain users are based in Australia and it is installed on at least five draglines in North America,” Barton said. “In the coming years, Columbia Steel anticipates more TwistLink chain trials and adoption by North American dragline operators.”

Offering the benefits of standard chain, TwistLink weighs almost a quarter less, allowing operators to increase the load of overburden in every swing of the bucket, he said. “Reducing chain weight can potentially allow for the use of a larger bucket,” he said. “Some dragline operators choose lighter weight rigging to reduce the load on their dragline.”

The chain is cast from the same H-series steel alloy as the company’s XtraLife chain, which is described by the company as the industry standard. The material offers “high tensile strength and toughness,” and provides “good resistance to abrasion and excellent ability to handle impact” and shock loading, Columbia Steel reported.

TwistLink is available with Columbia Steel’s Xtend Process high-carbide overlays and manganese overlays.

Company literature described the chain as contoured for smooth operation and increased flexibility. Other benefits include increased surface area in the bite region, increased cross-sectional strength, the resulting cost savings, and the availability of weld-in repair links.

Barton said the solution should speak to American customers seeking to optimize their rigging. “Any dragline rigged with 2 ¼-in. to 4 ½-in.sized chain can make the switch to TwistLink,” he said.

Since its release in 2002, the solution has helped the company build a reputation for making chain with “superior reliability and long wear life,” Barton said. “TwistLink chain is an example of Columbia Steel’s commitment to help dragline customers improve productivity and safety with innovative wear part solutions.”

Match Performance to the Task

With higher horsepower and its improved controls, Komatsu America Corp.’s newly released PC2000-11, equipped with a Tier 4 Final engine, can strip more overburden and load more trucks per hour than its predecessor, the PC2000-8, the company reported.

Announced in September, the excavator uses “EPC valves to control the work equipment, which optimizes hydraulic flow for improved multifunction performance,” Robert Hussey, product marketing manager, Komatsu America, said. “The machine also has 9% more net horsepower,” he said. “The direct benefit of these two changes are more power when digging and faster cycle times when loading trucks.”

Enabling the miner to best match performance capability to the task, the PC2000-11 offers four working modes.

Power Plus mode is “for customers who need the maximum available production,” Hussey said. It offers 12% more productivity than the PC2000-8.

Economy 1 mode provides the maximum amount of fuel savings, up to 15% in comparison to the predecessor unit.

Between the two are Power mode and Economy mode.

The excavator has auto-idle and auto-idle shutdown, both of which save fuel, Hussey said. “For other support work around the coal mine, the PC2000-11 has a heavy-lift functionality, which initiates the maximum power of the boom circuit, increasing lift force by 10%.”

Compared to the PC2000-8, it features stronger boom plates and castings, strengthened track and center frames, larger-diameter carrier rollers, and improved hydraulic cylinder seals. Thus, components are built to last, the company reported.

When maintenance is required, “a ground-level service center reduces the labor hours for preventative maintenance services,” Hussey said. “Standard engine pre-lubrication, an automatic greasing system, and hydraulic filter bypass detection increase long-term durability and reliability, ensuring the customer is receiving maximum value for each hour the unit is in production and reducing maintenance costs.”

As a Tier 4 final machine, the excavator requires “the use of additional technology and aftertreatment to achieve compliance with EPA emission mandates,” Hussey said. However, the maintenance routine and amount of consumables used is less than other Tier 4 Final aftertreatment solutions in the marketplace, he said.

“Unlike some other Tier 4 Final solutions, Komatsu’s PC2000-11 does not require a selective catalytic reduction system and therefore does not require diesel exhaust fluid as an additional consumable fluid,” Hussey said.

KomVision is a standard feature on this machine. It is a seven-camera system that provides the operator with a bird’s-eye view of the working area on a dedicated 10.4-in. LCD touch screen in the cab, Hussey said. “In overburden stripping applications, there are often a high number of haul trucks involved, so the KomVision system helps improve operator awareness in the working area.”

The excavator is designed to load 70-ton to 200-ton haulers.

Decrease Downtime

Caterpillar announced a drive system upgrade for the 7495 rope shovels that, the company reported, increases durability and component life, decreases downtime, and reduces costs. The upgrade reconfigures the crawler undercarriage to allow drive shaft and tumbler replacement from the outboard side.

The upgrade is designed to be a direct replacement, requiring no machining of the crawler frame.

With the upgraded drive system, “thrust loads are evenly distributed on large tapered roller bearings as opposed to bronze thrust plates,” the company reported. Bearings are sealed and continuously coated with fresh grease. “The result is increased durability in harsh environments and alignment with 25,000-hour planned rebuilds.”

The system is field tested, the company reported.

The 7495 has a 120-ton dipper payload and features an IGBT Acutrol drive system that comes standard. The original equipment is described by the company as being comprised of components that ensure system performance and “a long, trouble-free life.”