Making all the right choices can significantly reduce cost per ton, increase worker safety and minimize required maintenance.
|The largest loader in Cat’s LHD lineup, the R3000H shown here, has the bucket capacity and power to three-pass load the company’s largest underground truck, the AD60.|
By nature of the work environment, mechanized underground mining can’t offer the big-picture visibility of large-scale truck and shovel surface operations, and the open space needed for typical multi-truck loading patterns just isn’t available underground. However, the basic elements of surface-fleet equipment selection—such as appropriate size for site conditions, correct pass-matching between loaders and trucks, and proper machine configuration for optimal safety, reliability and maintenance—are valid and perhaps even more critical in underground operations, where fleet and individual equipment size and capacities are often constrained by work space limitations.
Equipment selection was high on the list of discussion topics during the underground segment of the 2014 Cat Global Mining Forum, held May 1–3 in Tucson, Arizona. Cat’s Global Mining product line manager, Jay Armburger, led off by noting that Cat has, since its acquisition of Bucyrus in 2011, focused on developing its underground equipment and services portfolio as a core strength for the company. Accordingly, among its recent product introductions are a half-dozen “all-Cat” machines and systems for the underground market, including the R1600H LHD—which just became commercially available—along with the R3000H, which was unveiled at MINExpo 2012 and has since entered the market, and the AD60 mine truck. The company also has developed a Ventilation Reduction Package for underground equipment and a new diesel particulate filter, and has indicated that its progress on design and testing of a two-boom development drilling jumbo is proceeding satisfactorily.
|This AD60 is equipped with Cat’s Diesel Particulate Filter (mounted on the deck above the tire). The filter medium is optimized to work with Cat’s new Ventilation Reduction Package engine hardware and software to deliver a more than 50% reduction in exhaust particulate matter.|
Measuring Up Underground
When it comes to the primary considerations for sizing and equipping an LHD, according to Cat’s senior product specialist, William Edwards, the main concerns are:
- Width and height–What’s the maximum width allowable for an LHD in an operation? Take into account not just the dimensions of the machine’s usual workspace, but all spaces in which it may have to pass through to relocate. Also, pay attention to the actual height of underground work areas by noting any hanging ventilation or mine-service structures that could interfere with machine operation.
- Loading method and bucket selection–Will the LHD be loading trucks or carrying to a dump point? Bucket selection should consider the machine’s primary use and the characteristics of the material that will be loaded; a standard bucket design may work well in many applications, but a high-penetration design will be needed for others. If a high-penetration bucket is required, keep in mind that load spillage will be somewhat higher. The bucket’s ground engaging tool (GET) system is another important factor; should it be a weld-on or a mechanically attached system? Wear liners are also available and sometimes mandatory depending on the material being loaded—but keep in mind all added-on parts and material reduce bucket payload.
- Options–Consider what conditions encountered at the work site need specific optional equipment, which can range from a choice of open or closed cab styles to remote control-ready configurations, or ride-control systems to integrated machine-recovery attachments for stranded equipment.
A similar approach should be used to size and equip underground trucks, said Craig Johnstone, Cat senior product specialist. What are the drift dimensions? Will trucks be loaded by LHD or chute? What’s the density of the material that will be loaded? If trucks are loaded by LHD, will they side- or rear-load? Does the mine layout lend itself to conventional dump bodies or is an ejector body required? Open or closed cab? And which optional features and accessories will be conducive to improved productivity and safety, such as a payload management system, onboard fire suppression equipment or fast-fill fluid service system, for instance?
After the loaders and trucks are purchased and commissioned underground, the next challenge is to identify the best approach for extracting maximum productivity from them. When planning any productivity improvement program, keep two primary issues—cost cutting and increasing tons loaded and hauled—in mind, and keep any productivity-enhancement efforts simple, said Chris Gehner, Cat’s hard rock underground marketing manager.
Although cost reduction is a legitimate and often fruitful pursuit, some costs just can’t be cut or controlled closely enough to make a sizable difference, commented Gehner—but “tons per shift” is where machine and operator efficiency improvements can lead to significant gains. “Small changes can add up,” he said.
Start by sitting in the trainer’s seat of the vehicle for half a shift and take note of any observed inefficiencies or delays; or, “sit on a rock”—observe machine activities from outside the cab and note the conditions present in the work area. Use technology to assist in evaluating operations; look at ECM data, load factors or idle time, for instance. Develop “measurables,” such as best cycle times, drawpoint and haul road condition, payload accuracy, etc. Then validate and quantify the improvements.
In some cases, improvements will be obtained only through efforts that will cost the mine money, Gehner cautioned. These expenditures must have an acceptable ROI.
|Sandvik’s new LH204 LHD, pictured here, along with the upgraded LH410, offers the Vehicle Control and Management System for faster diagnostic troubleshooting and less downtime.|
Introducing the 1600H
Cat recently launched the R1600H LHD, replacing the R1600G model. The 10.2-metric-ton-capacity 1600 series loader is the best-selling model of Cat’s LHD line, and is being manufactured in the company’s Rayong, Thailand, factory.
The H version features changes and enhancements to the engine and cooling system, operator station, safety and serviceability, durability, and equipment management. Several standard features on the H were options on the previous model.
The R1600H is equipped with a Cat C11 ACERT engine rated for operation up to 4,500 m above sea level without component changes. Two engine options, U.S. EPA Tier 3 and Ventilation Reduction (VR), are available to suit different regional needs. VR engines, through minor engine modifications and adjustments, emit lower amounts of particulate matter, which can reduce ventilation requirements.
The axle cooling system now uses the engine jacket water to cool the axle oil. The cooling capacity has been increased to meet the requirements of the C11 engine and axle cooling system.
The R1600H has improved operator and technician features with an upgrade to cluster gauges and the CMPD (Color Multi-Purpose Display) monitoring system, allowing more information to be available to the operator and technician without the use of the Cat Electronic Service Tool. The display can also be programmed by the operator or technician for different languages and measurement systems.
The Operator Present System is now provided on the R1600H. It is a safety feature that keeps the parking brake engaged and hydraulic implements disabled until the operator is present and the machine is ready for safe operation.
The VIMS Guardian Third Generation System is available as an option for the R1600H. This technology enables Cat equipment to provide detailed, up-to-the-minute data about its own health and working conditions by monitoring key temperatures, pressures and more.
Cat announced in late March that its R3000H LHD’s field follow program had been completed, with more than 2,000 hours of operation accumulated underground. According to the company, all of the LHD’s structural designs and machine features proved successful during the program. The R3000H is the largest LHD in the Cat line and is designed for a rated payload of 20 mt in both load-and-carry and truck loading applications. Cat said the R3000H offers a 16% production advantage over its predecessor, the R2900 XTRA, in truck loading applications. With its added capacity, the new model provides a three-pass match with the new 60-mt AD60 underground truck.
Cat’s LHD product line now extends from the R1300G—the smallest—to the R3000H, covering minimum underground work-space cross-sectional dimensions ranging from 3 x 2.8 m to 5 x 5 m.
Filling in the ADT Product Line
A Cat spokesman said the company’s AD60 articulated dump truck, also introduced at MINExpo 2012, has been well received in the underground market and joins the company’s AD30, AD45B and AD55 (Flat Haul) models.
At the time of its introduction, Cat said the truck’s C27 engine, rated at 776–805 gross horsepower (579–600 kW) had been significantly refined for use in the AD60, including new pistons and high-temperature fuel injectors, more durable rocker arm assemblies, a redesigned crank-shaft lubrication system, a high-efficiency engine oil cooler and a higher-capacity fuel cooler.
The latest version of the AD60 also has a remote-mounted transmission oil cooler for the seven-speed Cat planetary powershift transmission, which features a lock-up torque converter as well as an electronically controlled retarding system. The trans cooler lessens the heat load on the engine oil cooler. In addition, a new heat-shielding system isolates heat from the exhaust manifolds, turbocharger impeller, and exhaust piping to reduce engine compartment temperatures and to provide a cooler environment for surrounding components. New ventilated hoods and covers allow effective heat dissipation and assist in passive cooling of component compartments.
Other major features on the AD60 include electronic integration of the engine and drive train, providing controlled-throttle shifting, overspeed protection, and body-up shift inhibitor. And, currently, the AD60 is the only ADT model on which Cat’s Truck Payload Management System is standard equipment.
Underground Force, part of Idaho, USA-based mining utility vehicle builder Ground Force Manufacturing, a Cat business partner, recently introduced its line of articulated dump trucks that includes 10-, 15- and 20-ton payload capacity models, filling the gaps in Cat’s underground haul truck product line. The underground trucks are offered in ejector, side dump and end dump models with Tier 4 and LRC engine options. The trucks, according to Under-ground Force, include AR400 steel components for durability and employ 65% Cat parts in their design.
|Atlas Copco’s ST18 is designed for high-rate development and production applications.|
Sandvik LHD for the Chinese Market
In March, Sandvik Mining announced the introduction of its LH204, a 4-ton-capacity LHD designed for narrow-vein underground mining applications and developed initially for the fast-growing Chinese market.
“The LH204 operates productively and profitably in confined applications while still handling larger payloads than similar-sized competitor units,” said Mika Pöyri, Sandvik Mining product manager. “The increased 4-ton payload capacity results in a productivity increase of at least 13% compared with other LHDs in this size class.”
The LH204, now available in China and in other global markets later this year, features powertrain, engine and transmission improvements that translate into higher penetration rates for efficient loading of the 2-m3 bucket, according to Sandvik.
“It also offers the highest levels of safety and ergonomics in this size class,” Pöyri said. “For example, the operator’s compartment is located in the rear frame and we can offer the option of a fully enclosed cabin for extra operator safety and comfort.”
Unique in this class of LHD, said Sandvik, is its Vehicle Control and Management (VCM) system, which monitors all loader parameters, including tramming speeds, operating temperatures and pressures. This expedites troubleshooting and minimizes unscheduled downtime. In addition, all daily check and fill points are at ground level, facilitating safe and easy maintenance.
“This loader is the result of a design process that combines local market requirements with 30 years of Sandvik Mining experience in designing safe, reliable LHDs and applies our core technology benefits to a machine tailored for developing markets,” said Pöyri.
Concurrently with the announcement of the LH204, Sandvik introduced an upgrade of its LH410 LHD earlier this year, aimed at improving the machine’s operational flexibility and productivity. Feature enhancements include a complete re-design of the front end to improve the loader’s capability to load trucks—it’s now able to three-pass load Sandvik’s TH430 underground mine truck.
Changes to the loader bucket and arm geometry have elevated the bucket pin height 312 mm to 3,863 mm. The LH410 features a strong, lightweight box-construction boom, designed for strength, reliability and durability while minimizing fuel-wasting dead mass, according to Sandvik. Improvements to the LH410’s optional boom suspension system have been designed to deliver a smoother ride in bumpy underfoot conditions, resulting in more operator comfort, reduced machine wear and better load retention.
The loader also has a larger boom/bucket pump for better control and faster dump speeds and an improved bucket-shaking system to increase dump speeds, particularly with muddy or sticky materials. To optimize load distribution and facilitate dumping, it now has a redesigned bucket with an improved profile for easier bucket filling and faster dumping.
Additional enhancements include ergonomic improvements to the accelerator and brake pedals, an upgraded oil cooler and improved transmission and torque converter cooling, and a relocated air filter that is easier to access.
An optional monitoring system for tire pressure provides early warning for potential tire problems.
“The LH410 is automation-ready, enabling it to be integrated into a Sandvik AutoMine operation by installing an available upgrade kit,” said Minna Pirkkanen, Sandvik product manager for mass mining underground loaders.
Atlas Copco LHD Aims for Top Productivity
Late last year, Atlas Copco launched a new, 18-mt-capacity underground loader for large operations, including development work as well as production mining. Designed to match the company’s 60-mt-capacity Minetruck MT6020T, Atlas Copco said it expects the Scooptram ST18—which completes its range of LHDs in this segment—to be the most productive LHD on the market. The company also noted that the ST18 and the MT6020 share many common parts and control system components, which can substantially reduce total cost of ownership.
Describing one of the LHD’s key features, Ben Thompson, product manager at Atlas Copco, said “[An] optimized bucket means better muck pile penetration, faster acceleration and faster dumping. The result is a better load factor on the truck and, in the end, a higher tonnage per month.”
A new bucket and a unique boom design, combined with variable displacement pumps, plus the Atlas Copco Rig Control System, which monitors and controls all aspects of the operation, results in superior muck pile penetration, less wear and tear on the machine, and an overall faster and more productive loading cycle, according to the company.
The operator is secure inside a FOPS/ROPS-approved, air conditioned cab and has extra leg room thanks to a unique footbox. Atlas Copco said the layout of the controls is ergonomically efficient and operator visibility—even toward the rear—has been improved by the LHD’s sloping design and shorter power frame structure.
Safety features incorporated into the Scooptram ST18 include automatic brake test, protection guards, three-point access system, redundant steering system, safety latches, boom lock up, fire suppression systems, machine protection system and others. It can be configured to run semi-autonomously or by radio remote control.
Features such as automatic ride control and automatic declutch are claimed to increase the service life of the loader and to reduce spillage from the bucket. Automatic traction control can reduce tire wear and fuel consumption and the addition of soft stops on the boom, bucket and steering reduce unnecessary stress on the machine.
The ST18 comes with a number of Atlas Copco Service products that are intended to contribute to trouble-free operations. One example: the RigScan, an advanced audit service product that offers a real-time, non-intrusive look at the equipment’s operational condition and performance. Another is the Remote Monitoring system, providing production and maintenance data through a Web interface.
Atlas Copco said it also offers a training program consisting of classroom, simulator, and on-site training. By using the Scooptram ST18 training simulator, new operators are given the opportunity to practice harmlessly on machines and systems before entering the mine environment.
|The Paus PFL 8 Z LHD at work in a Ukrainian iron-ore mine.|
Paus’ LHD Offers Big Performance in Small Spaces
German-based Hermann Paus Maschinenfabrik GmbH launched its PFL 8 Z LHD in 2013. The machine, according to the company, has since then established a niche for itself among customers pleased with the performance of what Paus calls its “little powerhouse.”
As an example, Paus cited its recent experience with Ukrainian iron and steel producer ZZhRK, one of Paus’ customers for the PFL 8 Z, which had for many years used obsolete, pneumatic-drive mining machines from the Soviet era in much of its underground mining program, particularly for work in remote tunnels or tunnels with a small cross-section.
Those machines, built over half a century ago, were inadequate to meet modern requirements in terms of safety, technical development and cost-effectiveness. As part of an expansion of its mining operations in the late 1990s, the company began to acquire new, more productive machines, and more recently commissioned a PFL 8 Z LHD at its NN iron-ore mine.
According to Paus, the Ukrainian company is pleased with the machine’s performance. Compared with the older machines, the PFL 8 Z provides improved safety during transport and loading, while its compact dimensions enable it to be placed in underground spaces without major disassembly—only the LHD’s bucket and swing arms had to be removed when it was brought into the Ukrainian ore mine, making travel to the work area a much simpler process.
Citing such features as advanced ergonomics in the operator cabin, good visibility and easy access for maintenance and service encountered in the trial unit, the Ukrainian producer has since ordered additional machines, according to Paus.
Profiled in E&MJ earlier this year (See Mining Machines for Small Spaces, p. 28, E&MJ, March 2014), the PFL 8 Z incorporates design elements drawn from Paus’ experience building loaders and other mobile equipment for use in hard-rock mining at altitude and in extreme conditions. With an unladen weight of 5,300 kg, a payload of 1.8 mt and bucket volume of 0.8 m3, the PFL 8 Z is intended for ultra-small-scale mining environments. The loader is powered by a 69-kW air-cooled Deutz diesel engine, available with different emission-control levels for specific markets and offering high torque, excellent exhaust emission levels and low fuel consumption, according to the company, which also noted that the loader’s Power Drive System automatically adjusts traction power and speed to current mining conditions, reducing tire and brake wear and thus overall operation and maintenance costs
In addition to its standard configuration, the PFL Z 8 is available with a variety of bucket versions for specific job applications. An optional quick-change system allows the machine to be fitted with specialized items such as fork arms, crane hooks or even a work cage, according to the company.
GHH Busy with Equipment Updates
GHH Fahrzeuge GmbH, in Gelsenkirchen, Germany, has been manufacturing LHDs, trucks, special purpose vehicles such as scaling rigs, and drills and bolters (in cooperation with its subsidiary MineMaster in Poland) for underground mining and tunneling applications since 1964.
GHH Fahrzeuge is part of the Schmidt, Kranz & Co. (SK) Group, and currently maintains subsidiaries in Australia, Chile, China, Russia, Poland and RSA while covering most of the other countries through a comprehensive network of agents.
GHH’s range of products spans machines employing fundamental, relatively simple technology up to hydrostatic drive train-based machines and super-low profile-loaders. Its LHDs, available in capacities of 5 to 20 t, are designed to be used in extreme mining conditions and low and narrow galleries. The current LHD portfolio includes 15 different diesel- and electric-driven LHD models. Its super-low-profile loaders—the SLP product line—with a machine height of 1.5 m, can operate in galleries less than 1.7 m high. According to the company, African mine operators have shown high interest in compact GHH LHDs from the LF and the SLP product range, and South Africa-based GHH MM provides machinery as well as extensive services and training to the growing African market.
GHH also offers seven mine truck models for mining and tunneling applications, with payloads ranging from 15 to 55 t. All GHH models are designed around the robust GHH frame and system design aimed at providing low operating costs.
Recent developments include a new version of the compact, 5-mt-payload LF-5 LHD, which is now in production. This upgrade features a water-cooled Deutz TCD 2012 Tier 3 / COM IIIa-compliant diesel as standard equipment, with a Deutz TCD 4.1 Tier 4i and 4f-compliant version available as an option that significantly reduces required underground ventilation rates, according to the company. The new LF-5 also has ROPS/FOPS and CE certification, as well as various ergonomic improvements to provide maximum performance and flexibility in narrow (1.8 m) hard-rock mining or tunneling conditions.
The company said its 10-mt-payload LF-10 LHD has proven to be a durable and versatile LHD with an excellent power to weight-ratio and a simple, efficient design. The latest version of the LF-10 features engine improvements (water-cooled Deutz TCD 2013 diesel complying with Tier 3/COM IIIa), as well as improved operator ergonomics and controls. Visibility from the ROPS/FOPS-certified operator cabin has been enhanced significantly.
The company also announced a new version of its 20-mt-payload MK-A20 truck, featuring new dump body options, ROPS/FOPS certification and a water-cooled Cummins QSB6.7 engine complying with Tier 3/COM IIIa emission standards, as well as various operator ergonomic improvements. Its dimensions (9.4 m long x 2.2 m wide x 2.55 m high) and high power-to-weight ratio allow operations in narrow conditions. The MK-A20 shares the same platform with the MK-A5m3 mixer truck, a compact and versatile concrete mixer.
GHH also offers electric LHDs with payloads ranging from 10 to 20 mt. Its newest generation of electric units is equipped with the GHH-designed Efficient Drive System (EDS), an innovative hydrostatic continuous variable transmission concept combined with a constant-speed electric motor. Electric LHDs are equipped with a horizontal active-controlled cable drum, and the company claims that its precise cable-winding combined with low cable tension allows the service life of the cable to be extended significantly. The electric LHDs are suited for applications where production capacity must be increased without ventilation modifications.
The newest model in the electric line, the LF-18HE, is currently working in potash mines under extreme conditions with gradients up to 28% and temperatures above 40°C, demonstrating the capability and potential of EDS in combination with electric drives, the company noted.
EDS can also be applied to diesel-driven LHDs, offering advantages such as savings in fuel consumption, reduced tire and brake wear, better muckpile penetration, and easy handling in a single system.
|GHH’s LF-5 has been upgraded with new engine and ergonomic improvements.|
RDH Conveyor Truck Excels in Low-seam Ops
In late 2013, Ontario, Canada-based RDH Mining Equipment announced its Haul-master 600-7LPC conveyor haul truck, designed specifically for mining in low-headroom environments such as potash operations.
According to the company, the 600-7LPC’s chain-driven, sealed-bearing conveyor, built into the chassis, unloads to the rear, eliminating side spillage associated with the unloading of traditional haul trucks. The load mass is evenly supported by a series of robust crossbeams. The conveyor’s hydraulic power and control system allows the operator to adjust conveyor speed or stop it quickly.
Because the load body is never lifted, the truck can work in low seams or under obstacles such as ventilation or electrical structures—RDH said units were working in a 70-in.-high heading. The unit is stable, can unload on uneven surfaces and takes less time to unload than traditional dump trucks.
According to RDH, prior to the introduction of the conveyor belt truck, a mining customer used LHDs to carry potash from the face to a conveyor system. After the conveyor truck was commissioned, the operation reported a 400% increase in productivity due to quicker unloading time.
The Haulmaster 6007LPC’s load body can carry up to 6.3 m3 (8.3 yd3) of material and is rated at 6.4-mt (7-t) payload capacity. It is powered by a Deutz 914L06 air-cooled diesel.