Making the Most of Material Gains
Moving massive volumes of mine ore, waste or product is never easy, cheap or trouble-free, but new material handling tech can help smooth the bumps, cut costs and break bottlenecks.
By Russell A. Carter, Contributing Editor
That’s why successful mine operators are masters of material handling. In an industry that moves billions of tons of dirt and rock annually at surface operations and where new underground projects are targeting mining rates of 100,000 tons per day (t/d) or more, a few percentage points of material-handling ineffi ciency can translate into lower profi t margins.
The expanding scope and functionality of digitally oriented, comprehensive bulk handling packages offered by major players such as thyssenkrupp Industrial Solutions, Tenova TAKRAF, FLSmidth, Metso and others seems to point to a shift in vendor and end-user focus away from solving material-handling challenges by application of sheer physical-equipment force, to a digitalized, collaborative and often cloud-based approach that provides wider, deeper insight into bulk operations and allows end users to detect and alleviate bottlenecks, while optimizing the use of existing assets and requiring fewer workers on the ground. However, despite the trend toward digitalization, there will always be a need for new “iron” — the latest generation of conveyors, feeders, stacker/reclaimers and custom-designed special-case material handlers in a market that is expected to grow at an annual rate of 4.5% or more during the coming years. A sampling of recent material handling projects bears out this projection. For example:
Siemens and thyssenkrupp Industrial Solutions announced they will collaborate to provide high-capacity conveyors for Anglo American’s new Quellaveco copper mine in the Moquegua region of Peru. thyssenkrupp will supply a 4,700-meters (m)-long, 1,830-mm-wide overland conveyor featuring dual Siemens 5.5-megawatt (MW) gearless drives operating at a design tonnage of about 11,000 t/h. The scope of supply also includes the complete material handling system for the concentration plant, comprising eight inplant conveyors and 11 belt feeders.
The new conveyor system will initially move 127,500 tons of primary crushed ore per day from the pit to the stockpile adjacent to the copper concentrator. The conveyor will pass from one valley to another through a 3.2-km-long tunnel. At the stockpile end, the system’s stacker is designed to allow the mine to replace the discharge pulley without the need to clear out the stockpile for crane access. First production from the new mine is expected in 2022. thyssenkrupp also designed similar systems for the Antapaccay and Las Bambas mines in Peru.
Rio Tinto selected FLSmidth to supply key equipment for a new iron ore mine in Western Australia. The turn-key contract, valued at $56 million, is for design, supply, installation and commissioning of bulk material-handling equipment for the Koodaideri greenfi eld project. FLSmidth said it will design the equipment to current Australian standards and incorporate smart 3D design and a variety of advanced engineering solutions such as BulkExpert, the company’s well-established stockyard and train load-out automation package that uses 3D laser-scan technology.
Construction at Koodaideri will begin this year. Full annual production capacity will be 43 million metric tons (mt) of iron ore. A recent technical report described the general scope of the project’s plant-related materials handling requirements: Final product will be conveyed and stacked separately on to lump and fi ne product stockpiles, then retrieved by a bucket- wheel reclaimer. The product stockyard will have two slewing and luffi ng stackers of 5,700-t/h capacity, one for fi nes and one for lump products, as well as a single slewing and luffi ng boom-type bucket- wheel reclaimer with an average stockpile reclaim capacity of 4,690 m3/h. The reclaimer will collect either lump or fi nes for transfer to a load-out system capable of fi lling a 240-car train in 200 minutes.
As part of a billion-dollar capex program aimed at sustaining existing operations at its Western Australia iron ore operations, Rio Tinto Iron Ore also is spending about $50 million to replace two ageing stockpile stacker machines at its Paraburdoo mine with new units from Tenova TAKRAF. According to Rio Tinto, the old machines were part of the mine’s original infrastructure, stacking the fi rst load of iron ore from Paraburdoo in 1972. In 46 years of operation, they stacked more than 800 million tons of ore, reportedly requiring only minimal structural changes throughout that time.
TAKRAF said its offi ce in Perth will manage the entire project, with support provided from the company’s offi ces in Brisbane and global competence centers. The design of the new stackers is under way and the start of fabrication is scheduled to begin later this year with installation and commissioning completed by early 2020. In April, Bosch Rexroth announced it had been selected to supply the drive system for what is thought to be the world’s largest rail-mounted bucket wheel reclaimer. Featuring an ore-moving capacity of 20,000 t/h, the reclaimer will be installed at the new BHP South Flank iron ore mine in the Pilbara region of Western Australia.
Bosch Rexroth will deliver the bucket- wheel drive system to thyssenkrupp Industrial solutions, which will design, supply, construct and commission the complete machine. The drive system will be based on Bosch Rexroth’s Hägglunds hydraulic direct drive technology, which it said offers a fl exible-drive layout that is well-suited to bucket-wheel reclaimers. The system will utilize the largest hydraulic motor ever built, the Hägglunds CBM 8000.
In addition to the bucket-wheel drive system, Bosch Rexroth will supply Hägglunds drive systems for the slew function on both the bucket-wheel reclaimer and two stacker machines at the same mine site. Each slew drive will comprise four Hägglunds CB motors with torque arms and brakes. According to Hägglunds, its hydraulic direct-drive systems provide the high torque needed for bucket-wheel reclaimers, yet remain lightweight and highly fl exible. The hydraulic motor is mounted on the boom to drive the wheel shaft, while the drive unit with electric motors and pumps can be situated in a more central position on the machine. In many cases, this lets equipment manufacturers reduce steel bulk and counterweight, which results in a leaner, more agile and more fuel-effi cient machine.
Metso used Hägglunds CBM hydraulic motors in the feed system for a new crushing plant at Boliden’s Aitik mine in Sweden, a facility that will be instrumental in reaching the company’s long-term goal to raise that mine’s production from 36 million to 45 million tons of crushed ore by 2020. One of the reasons why Boliden decided to invest in apron feeders powered by direct hydraulic drive was frequent problems with gearboxes. Another was curiosity. Jörgen Larsson, project manager at Boliden, explained the original crushing plant had feeders that “…were unreliable in every way. We had many gearbox breakdowns over the years and wanted to improve availability. This will be a test of hydraulic technology. I have seen Hägglunds drives in various reference installations around the world, and during my investigations I did not hear of any negative experiences,” said Larsson.
The new feed system, incorporating horizontal apron feeders to the crushers, is a proven design with many installations in use around the world. Metso adapted the system to suit the particular needs of the Aitik mine. In addition to improved availability, Boliden set other high performance demands for the equipment and Metso accordingly developed a design based on two CBM 2000-1400 motors sharing the load on each feed unit, with a capacity of 8,000 t/h, variable speeds from 0 rpm to 7.46 rpm and a starting torque of around 1,000,000 Nm.
“We wanted to have some power in reserve, so that’s good. It gives us a maximum capacity of 9,000 tons per hour. It also gives us redundancy for all the main components, so we can drive with one motor if needed,” said Larsson.
On the Pad
Successful heap-leach operations need consistent, controllable placement of ore on the leach pad and, in the case of dynamic (on/off pad) leach operations, the ability to remove spent ore effi ciently and relatively quickly. Recent developments at two German fi rms, FAM and thyssenkrupp Industrial Solutions, highlight equipment capabilities that cater to these needs.
thyssenkrupp introduced the lizard system for stacking ore and tailings earlier this year, explaining that it merges two established material handling technologies — the conveyor bridge and the crawler- mounted tripper car — into a new concept that features a tripper car decoupled from the conveyor bridge, allowing it to be controlled independently of the bridge. According to the company, a standalone tripper car has several advantages. Because there is no stress from a traveling tripper car on top of the bridge, the bridge’s structural components can be less bulky and truss assemblies can be of a simpler design, which results in a lighter, lower bridge confi guration with smaller bridge crawler drives and reduced ground pressure.
The bridge span’s fl exible joints aren’t stressed by the additional intermittent load of the tripper car when it is traveling over the connected bridge segments, alleviating fatigue issues caused by cyclic loading. With lighter loading on the bridge, reduced bridge construction costs balance out the cost of the additional chassis and structure of the tripper car. This design cuts capex requirements, says thyssenkrupp, and allows greater dump height and longer outreach. The same light design can be applied for the reclaiming bridge.
Another important element of the lizard is its multi-crawler drive system. thyssenkrupp said it has applied a unique solution to optimize productivity: A multi-crawler chassis is attached to the tripper car. The individually controlled crawler tracks allow movement in all directions without constraint. This system can be attached to any crawler to eliminate the wide steering radius commonly required by conventional gearing systems that are normally attached to these machines.
The system is designed to offer greatly improved overall fl exibility. As shown in the accompanying diagram, when the stacking bridge fi nishes a row, the tripper car will be at the bridge head or tail end. Before moving to the next row, the tripper car turns its crawlers 90° in the direction of bridge movement without impact on the system’s performance. The tripper car moves in concert with the stacking bridge as an integrated stacking system.
In the Yard
The massive bauma 2019 trade show held earlier this year in Munich, Germany, provided a showcase for vendors to highlight not only new equipment, but new concepts in automated stockyard and port systems bulk material handling systems. For example, thyssenkrupp Industrial Solutions’ full package comprises four components:
Operator-less and remote operation – Machines, with minor exceptions, included in thyssenkrupp’s smart stockyard and port solutions will be fully automated; they can be remotely operated from a central control room, allowing the number of workers involved to be reduced because no direct human interaction or presence on the machinery is required.
Maintenance Assistance System (MAS) – MAS visualizes, plans and schedules maintenance tasks. Usage-based maintenance intervals are calculated automatically, and necessary maintenance tasks are assigned to personnel. Locations requiring maintenance are displayed visually. MAS is mobile device-ready and has secure user authentication and an authorization management system. The system’s easy confi gurability allows maintenance tasks to be modifi ed based on company policies, according to thyssenkrupp Industrial Solutions.
Stockpile Management System – This pairs material-fl ow detection with pile-scanning instrumentation to create an accurate and robust “digital stockpile” that is updated in real time and allows multiple machines to work simultaneously on the same stockpile. Through 3D map visualization of stockpile condition and shape, pile gaps can be quickly detected and corrected. The coordination of all stockyard machines reduces unnecessary machine movement, resulting in higher effi ciency.
Drone-based inspection – With drones being touted as the perfect tool to inspect hard-to-access assets, this capability allows customers to get quick, cost-effective, safe and thorough insight into stockpile conditions without need of workers scrambling on the piles. The 3D scans from the drones can be supplemented with additional information gathered by thermal cameras mounted on the drones. Thermal information can be used for condition monitoring or for identifying temperature- related damage.
thyssenkrupp said it can evaluate, in detail, machine and process data from plants worldwide with a state-of-theart analysis system. Data is stored and pre-processed in a structured manner on site to ensure data quality. The structured data base is transmitted in encrypted form to the thyssenkrupp IoT cloud, where it can be further analyzed to detect anomalies or recognize patterns. Through careful technical evaluation, thyssenkrupp said it can determine optimization potentials for a plant, its machines and operations, and can provide recommendations for achieving improvements.
ABB unveiled the latest version of its Ability Stockyard Management System, designed to provide fully integrated, digitally based and collaborative stockyard and port operations by connecting all available information and process data for status monitoring and performance analysis. ABB said the system enables seamless integration in production planning, providing real-time information on handled material, and supports the management of single or multiple inputs and outputs of different material qualities, storage, mixing and blending. It is a confi gurable system that can be used to digitalize the complete material handling chain. The material fl ow can be modeled across all belt conveyors and transportation equipment with material properties and quality information via automated data interfaces.
Major features include:
• A calculated stacking model built up
according to the tracked material and
acting as a “digital twin” of the stockyard.
This provides the operator with an
inventory overview at any time, without
the need of an extra survey. All data can
be used for operational optimization
such as effi cient space utilization in a
yard, better planning and scheduling, or more accurate mixing and blending
• Control and prediction of material fl ow in various lines with material forecast, tracking and production history.
• The ability to coordinate all excavators in the mine or yard machines in the plant at the right position with the right timing, offering proactive production control, which enables online mixing of material according to tracking, forecasting and online quality control.
• Laser scanning or drone inspection enable a nearly real-time update of the pile surface even after material movements due to environmental infl uences or due to the use of mobile machines.
• A “slice view” feature, which gives operators a view inside a pile to check material mix and quality, determine its arrival time, or observe changing material properties.
• Modeling for intra-supply-chain quality optimization allowing operations staff to view tons and grade by digging position and belt-scale values according to information gleaned from geological models and online analyzers.
• Automated interfaces to other systems provide a seamless workfl ow from ERP to control system for mine, plant and stockyard operations. An integration of PIMS, MES, production, maintenance and downtime planning or laboratory management systems combines all available information for analytics at the right time.
ABB noted that the system employs sophisticated data collection and confi guration management to interface with various information technology applications and platforms. This includes connectivity to IT and ERP systems through Web services, TCP/IP socket communication or direct database access; as well as data interfaces with OT automation systems through OPC — and if OPC is not supported, through low-level data interfaces based on data wrappers.
Inside the System Although material handling equipment and systems typically employ large, robust and powerful machinery, the sum total of a given system’s performance depends largely on how well its individual components — including everything from sensors to software — have been integrated into its overall design and how effectively each of those components performs its assigned role. Here are a few examples.
ABB’s recently-introduced Ability Smart Sensor for Dodge mounted bearings enables “health checks” for bearings. Smart-sensor technology provides an early indicator of potential problems by assessing the condition of bearings from vibration and temperature information. This helps to prevent downtime on applications such as bulk material handling conveyors, according to the company.
ABB said the Smart Sensor uses the latest algorithms to assess, manage and ensure performance of components. Eighty percent of bearing failures are lubrication related and a bearing “running hot” can indicate that proper lubrication procedures are not in place. Monitoring a bearing’s vibration can indicate potential system problems.
The smart sensor is designed to easily mount to the bearing and communicates wirelessly via a smartphone or other device. This capability enables convenient access to the health data of bearings in hazardous or hard-to-access locations.
WEG announced it has just developed a new line of motors that incorporate special features and a new system of brushes and slip rings (wound rotor motors) making them suitable for operation in severe applications. WEG said its M Mining motors are designed with features that provide toughness, strength and long-lasting operation under aggressive environments typically encountered in mining. The motors offer IP66 protection and are suitable for handling critical loads in applications that require high starting torque. Slip ring motors are widely used in mining since they are specifi cally designed to drive high-torque load demands at low speeds, combined with low inrush current.
The number of parts and components has been signifi cantly reduced throughout the M line, and the use of non-stop pressure springs helps to minimize brush wear. In its liftable brush confi guration, the motor is equipped with a control and automation system for the brush-lifting operation, which is preset at the factory with full logical operation and fault monitoring via integrated HMI or from a remote location.
WEG claims the motor line allows users to simplify startup settings, reduce operating and maintenance costs, and increase the reliability of their systems. Dtect, another tool geared toward maintaining reliability in rotating machinery, was introduced by Voith. It’s an intelligent monitoring system that provides real-time data of driveline performance and coupling status, enabling an operator to take actions to prevent potential problems and avoid unplanned downtime. The company claims that by supporting better decision making, Dtect helps to increase productivity as well as signifi cantly lower production and maintenance costs. It is specifi cally designed to work with couplings such as Voith’s SmartSet, but also may be compatible with other existing couplings.
Through continuous measurement of the slip angle, Dtect accurately identifi es and monitors coupling slippage caused by high torque peaks in a driveline. According to the company, it uses an updated quadruple sensor setup that increases the sensing range without affecting the resolution of the measurement. By analyzing the slip behavior of the coupling, the operator can evaluate if the system is running at full capacity and if not, adjust the parameters accordingly. If necessary, proactive coupling maintenance can be performed to avoid costly downtime.
Dtect, said Voith, also makes it possible to monitor multiple couplings at the same time. It assesses each coupling individually and communicates the different parameters via a common interface. In this way, Dtect allows for simultaneous monitoring of all connected drivelines. Operators benefi t from comprehensive real-time status information provided by one central system.
Voith further explained that because Dtect has Modbus TCP/IP communications, it can be integrated into established process information networks and also paired with an integrated HMI touch panel for highest usability and control, with status monitoring at a glance. Visual warning indicators assist operators in making decisions and taking the necessary actions in any given situation.