CHAPTER 9.8 Automation and Robotics

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CHAPTER 9.8 Automation and Robotics

  1. 1. CHAPTER 9.8 Automation and Robotics Paul LeverINTRODUCTION Although these benefits are still appropriate today, theThe need to improve the productivity, safety, and profitability current renewed interest in automation and robotics in miningof mining is driving the widespread application of automa- is related to the following perceived additional benefits:tion technologies in mines. Automation in its many forms is • Limiting operational variance. Automation allowssomething that miners interact with on a daily basis but may be machines to be controlled so that their output is wellunaware of its existence. The current implementation of min- defined. For example, an automated shovel would loading automation and robotics has not yet significantly changed more consistent bucket payloads. This allows a truckmining processes. It has, however, begun to demonstrate its size to be selected for the shovel that will be consistentlypotential value to improve the productivity and safety of these loaded to its target payload.mining processes and associated unit operations. This has lead • Improved precision. Automation means mining tasks areto a growing vision within the industry that fully automated/ executed at their planned locations and times. For exam-robotic mining will be a major part of mining in the near future. ple, an automated blasthole drill will drill blastholes atThis vision includes mines that have the following capabilities: their precise location and specified depth as designated by • Automated personnel and equipment tracking the blast pattern (Holmes 2006). This means the outcomes • Automated materials handling—trucks, loaders, convey- of blasts are more consistent and generate the desired rock ors, sizers fragmentation, which has significant downstream benefits. • Smart drills—automated drilling of holes and recognition The more significant benefit of limiting operational vari- of material characteristics ance and improved precision is that they enable production • Accurate and automated movement and positioning of all consistency. This means that mine designs and, more specifi- mining equipment cally, mine plans, as well as production and schedules can • Automated mechanical mining systems be generated where there is a valid expectation that they can • Remote supervision from distant locations be achieved. Automation allows mining processes to be con- • Intelligent and integrated control over all mining pro- trolled more effectively (more like manufacturing facilities) cesses to optimize resource value where individual processes as well as the complete mining process can be optimized. The introduction of automationBenefits of Mining Automation is expected to serve as a catalyst for new credos for miningWhy does this vision of a fully autonomous mine exist today? similar to those that have evolved through introduction of totalTraditionally, the main perceived benefits for introducing min- quality management methodologies to manufacturing.ing automation have been • Improved safety—Removing operators from hazardous Definitions and stressful mining environments; To understand what mining automation and robotics are and • Higher productivity—Through the improved perfor- what potential impact they have on mining operations, it is mance of individual machines (more metric tons per important to define the basic terms: hour) and reduced downtime (automated machines see • Mechanized: Operations performed by machines less duty than human-operated machines); and • Automatic: Does not make decisions but completes task • Reduced labor costs—Automation removes operators by following well-defined rules from machines. Penman (2002) suggests labor accounts • Semiautomatic: Partly automatic and partly manually for approximately 20% of the cost of operating a large controlled haul truck. Paul Lever, Professor and CRCMining Chair, Mechanical and Mining Engineering School, University of Queensland, Brisbane, Australia 805
  2. 2. 806 SME Mining Engineering Handbook • Automation: Mining tasks completed by machines with- • Semiautonomous and remote-control capabilities that out human workers remove operators to safer environments, and • Autonomous: Functions independently without human • Collision-avoidance technologies that prevent accidents. supervision • Robotics: Machines with high-level capabilities to sense Mining Robotics—The Science and reason about their environment. Such machines are Field robotics is now well established in the research, com- required for successful automation of tasks in high vari- mercial, and military arenas. Mining robotics is a stream or able and unpredictable mining environments. application within field robotics. The basic science (with • Intelligent: Machines with the ability to learn, under- associate sensors, computing hardware, etc.) that drives the stand, and deal with new situations technology in this field is not being developed by the min- ing industry; however, mining robotics is using and reengi- neering this technology. Several good textbooks and journalsWhat Makes Mining Automation Challenging? explore the extensive science and technology of field robot-Automation is used extensively in many other industries ics. Buehler et al. (2010), Siegwart and Nourbakhsh (2004),and has demonstrated great value in improving productivity Everett (1995), and Ge (2006) are excellent references for(Gaimon 1985; Carlsson 1995). Its successful use in the man- more detailed information.ufacturing sector is in the automation of well-defined manu- Evidence of the close link between researchers in fieldfacturing cycles of identical components in a well-known and robotics and mining equipment manufacturers is Caterpillar’swell-structured environment. Mining is typically conducted sponsorship of the Carnegie Mellon University (CMU) par-as a series of discrete steps, or unit operations, by groups of ticipation in the Defense Advanced Research Projects Agencyequipment types working in tandem, such as drilling, blasting, (DARPA) Grand Challenge competition. This competitionloading, hauling, ground control, and materials processing. tests the performance of autonomous ground vehicles in aHere the highly variable and unpredictable mining environ- series of different outdoor environments and demonstrates thement affects the successful execution of each or sequences of state of the art in mobile robotics. CMU won the last competi-unit operations. Thus, automated mining systems must be able tion in 2007 and has been in a longstanding partnership withto sense, reason, and adapt to this unpredictable environment Caterpillar to develop automated mining equipment (Binningin order to function effectively. In addition, these systems 2009).need to operate for 365 days per year in very harsh mining A very large body of basic research into the develop-environments. For these reasons, many existing automation ment of autonomous vehicles includes major themes such astechnologies from other industries are not readily transferred route planning (Al-Hasan and Vachtsevanos 2002; Frazzoli etinto mining. al. 2002; Salichs and Moreno 2000); obstacle detection and The growth of robotics, driven primarily by the mili- avoidance (Azouaoui and Chohra 2002); close maneuveringtary, has provided the tools necessary to develop autonomous strategies (Gomez-Bravo et al. 2001); and autonomous vehi-mining systems. These developments have been driven by cle control system design (Pereira 2001).low-cost increases in computing power; new algorithms forsignal processing, perception, and control; and in particular, MINING AUTOMATION AND ROBOTICSnew sensing technologies such as Global Positioning Systems IN PRACTICE(GPSs) and radar and laser systems (Durrant-Whyte 2009). This section provides an overview of selected automationThese tools are essential to accurately locate, control, and solutions for the mining industry. Some are commerciallycoordinate the activities of robotic machines. Onboard sen- available, others are being trialed at mine sites as precommer-sors can generate real-time maps of the mine environment cial technologies, and some are still in the research and devel-(geometry and geology) around these machines so they can opment (R&D) stage. Detailed published information aboutbe optimally controlled. This spatial control information is many of these systems is difficult to find as manufacturers andessential to plan and schedule the complete mining process mines are reluctant to release information that might hurt their(including machines). This will make mining operations more competitive advantage.precise and predictable (like a factory) and ultimately dramati-cally more productive. Autonomous Haulage Systems—Technology Fully autonomous mining that encompasses the complete Autonomous haulage systems are generally divided into twospectrum of mining processes will be expensive and require major divisions: site-level systems, sometimes called thesignificant technical development. More importantly, it will office site manager, and machine-level systems, sometimesonly be achieved through significant change management of called the onboard controls.mining culture to accept these innovations. Mine automationtechnologies will achieve the highest probability of success Site-Level Automationusing a multistep implementation program. The resulting The site-level systems provide an interface between the humanearly introduction of technologies can provide mining benefits (and software-based) mine planners, provide data for businesssuch as tracking, and provide optimization and control over the haul- • Operator aids that improve machine performance and age system machines. Mine planning is defined as determining reduce machine damage, the goals and priorities and communicating them to the mine • Improved mine sensing systems that can provide manag- management tools, and mine management is defined as opti- ers with better information about the state of the mine, mization of existing resources to accomplish the goals. • New mine models that allow managers to execute opera- Mine planning. This requires significant human interac- tional decisions, tion to set goals such as prioritizing production volume versus
  3. 3. Automation and Robotics 807cost factors (fuel usage, risk of machine damage) or prioritiz- levels of availability. Unfortunately, specific areas (near theing short-term production versus long-term mine efficiency. poles) and areas with blockage to the east and west can haveThe challenge in mine planning is to ensure that both explicit significant problems with GNSS coverage. However, govern-and implicit goals are accurately translated to the more auto- ments around the world have pledged strong support to themated mine management system. GNSS infrastructure; and as more satellites are put in service, Mine management. Fortunately, there is a large body of the GNSS coverage should continue to increase substan-experience with mine management systems. However, a new tially. The most well-proven technology to augment GNSSgeneration of mine management systems will be required to for short durations is using inertial sensors plus odometry.address the requirements of autonomous systems. The next Unfortunately, this technology only has short-duration accu-generation of such systems will require much more detailed racy. Other possibilities for augmentation include pseudolites,mine models and many new features to manage autonomous often called ground-based satellites, or RF-ranging beacons.equipment. These systems allow individual mines to establish their own ground-based positioning system, which, unfortunately, canMachine-Level Automation be very expensive to install and maintain.Machine-level automation requires the ability to Clearly, the more types of independent positioning sources that are available, the more robust the positioning • Understand what tasks need to be accomplished (high- solutions will be. level planning); Perception. Autonomous machines generally need a good • Determine location (positioning); understanding of their surroundings to accomplish object detec- • Perceive the environment based on the location tion and sometimes assist with positioning. The perception sys- (perception); tem usually requires information from the mine model and the • Based on the environment and position, plan future tasks positioning system to accurately determine and report the loca- to achieve the desired goals (task-level planning); tion of objects. Perception sensors can come in several different • Execute the planned primitives (primitive execution); and forms: radar, laser, vision, and sonar (not discussed here). • Handle exceptions. Radar has been used since the early 1900s to detect ships High-level planning. High-level planning is the ability and large metal objects. More recently, millimeter-wave radarsto interpret directions from the mine management system and have been developed to detect objects for adaptive cruise con-to select the appropriate behaviors. For example, if an autono- trols and autonomous machines. Radar has the advantages ofmous truck is directed to a load area, it needs to understand long range and “seeing” through dust and fog. However, radarthe path, validate the path, and ensure that it has the required suffers from relatively poor resolution when compared tobehaviors and capability to execute the plan. laser-based systems. The size of an object that can be detected Positioning. Positioning is the ability to determine the depends on the object’s radar cross section (RCS), defined asmachine’s pose, meaning its location and orientation. For the projected area of a sphere that would return the same sig-autonomous machines, an accurate reliable pose is critical. nal to the transmitter. The most effective means to increase theAlthough absolute accuracy is actually not as critical, the effect of RCS is to install corner reflectors. Commercial unitsability to accurately register the machine’s pose to the mine are sold for small boats to improve their detection ability bymodel is a requirement. Multiple types of positioning must be radar. Corner reflectors can be thought of as “tail lights” forconsidered: radar transmitters. Laser systems provide the best resolution but suffer from • For aboveground applications, the most common real- obscurants such as dust and fog. Newer lasers overcome much time kinetic Global Navigation Satellite Systems (RTK of this limitation by using multiple reflections from each point GNSSs) are or from time gating the return to ensure that small, diffused – RTK GNSS + machine sensors (such as odometers), particles (dust, fog, rain, and snow) do not obscure other – RTK GNSS + machine sensors + inertial, objects. As the density of particles increase, the effective- – RTK GNSS + machine sensors + inertial + perception- ness of this method diminishes. As with radar, retroreflectors based positioning, and (such as tail lights or reflective tape) can be added to targets to – RTK GNSS + machine sensors + inertial + pseudolites greatly enhance their visibility to laser. (ground-based satellites or reference stations). Vision has significant promise for low-cost object detec- • For belowground applications, the most common types of tion and object recognition that is most like human perception. positioning systems are There has been a tremendous amount of work in this field and – Radio frequency (RF) based distance measurement, rapid progress is being made, but so far, vision is limited to – Perception-based positioning + machine sensors, and relatively short-range applications. Vision also is sensitive to – Perception-based positioning + machine sensors + shadows, dust, fog, rain, snow, and reflective surfaces (e.g., a inertial. reflection in a puddle may be confused as a real object). These positioning systems are well known in the indus- Combining multiple spectrums has significant advan-try. Perception-based positioning systems have been used in tages. For example, combining radar and laser gives the lon-restricted environments such as factory settings for more than ger range and improved penetration of radar with the laser’stwo decades (Caterpillar 1991) and in underground mining ability to detect smaller obstacles and improved object clas-applications for nearly a decade (Ferret 2003). RTK GNSS- sification. As another example, combining laser and visionbased positioning systems have been used to provide centi- allowed the TerraMax team (in the Grand Challenge com-meter-level accuracy in construction applications for a decade petition mentioned previously) to recognize tumbleweeds in(Saghravani et al. 2009). RTK GNSSs are susceptible to poor the desert that stumped a vision-only system in earlier testsGNSS coverage and must be augmented to provide very high (Broggi et al. 2010).
  4. 4. 808 SME Mining Engineering Handbook Unfortunately, there are currently no practical standard- mine in Chile, has been operating 11 autonomous haul trucksized tests by which to easily determine the capabilities of since 1997. More recently, Rio Tinto, at its West Angelas mineobject-detection systems under all conditions. in Western Australia, has been operating five trucks since late Another consideration for the practical use of autono- 2008 (Cribb 2010). Both sites are using 930E-4 electric-drivemous systems is that none of the obstacle-detection systems trucks with a payload of 300 t, and the trials are intended toavailable today have the ability to differentiate a pile of small test autonomous trucks in high-production scenarios. In bothloose rocks (e.g., a windrow left by a motor grader) from a cases, the ADTs are not working on the same haul roads withsingle large rock that could damage tires. manually driven trucks. Task-level planning. Task-level planning is defined as Komatsu’s FrontRunner autonomous haulage systemestablishing a sequence of task or behaviors to accomplish a operates as a comprehensive fleet management system forgoal and is generally rule- or constraint-based. As expected, mines. The haul trucks are equipped with vehicle control-task planning varies significantly based on the type of goal, the lers, high-precision GPS, obstacle-detection technology, andnumber of constraints, the variability of the environment, and a wireless network communication system. The system hasthe flexibility of the automated system. One of the common the capability to navigate a haul route, dump automaticallymachine-level planning tasks is object avoidance. to hoppers or to the ground, and work with some (but not all) Primitive execution. Executing planned primitives is loading equipment. The system leverages off several maturethe fundamental machine operation; some examples include technologies, notably the GPS and inertial navigation systemsdrilling, tramming, loading, grading, stability control, dump- for navigation, and millimeter-wave radar and laser systemsing, and ripping. These operations generally require continu- for safety and collision detection.ous closed-loop control and are probably the closest machine These technologies are integrated using largely fixedoperation to a human skill. automation strategies. Trucks navigate from a so-called pit Exception handling. Handling exceptions is the ability database, which serves the purpose of a haulage map andfor an autonomous machine to recognize that it does not have contains largely geometrical information, notably the bound-the means or required primitive ability to handle the exist- aries of the haul road, the truck’s travel path, and the bound-ing situation, and thus it resorts to fail-safe behavior—usually aries of the loading and dumping areas. The boundariesstopping and asking for help. represent the extent of the ADT’s allowed safe operation and The building blocks for autonomous haulage system are established by driving a light vehicle fitted with high-technology have been developed over the past two decades to precision (differential) GPS around the haulage perimeter.the point where commercially viable automation systems for The safe-working-area boundaries in load areas are updatedunderground mining are now available, and commercially via- as the shovel moves. As an ADT is manually driven alongble haulage systems for surface mines will be available within the required haul route at the required speed, the truck’s con-the next few years. In the near future, autonomous and intelli- trol computer records position, speed, and direction, defininggent remotely operated machines will provide the opportunity the truck’s travel path. The truck’s control system (steer-for remote operations centers that allow miners to work in the ing, braking, engine, and dumping functions) has the truckrelative comfort and safety of an office environment. These “replay” this path to navigate from the load area to the dumpfirst-generation systems should rapidly evolve to provide con- zone and back again. The use of the teach–replay approachtinuous improvement in efficiency, productivity, and machine used in current ADTs simplifies the problem of planning theavailability. truck’s course or path. The truck doesn’t need to plan its path; it knows its path having learned it in the training run.Autonomous Surface Dump Trucks The repeatability of the replayed paths under this approachOne of the principle benefits from using fully automated dump is high, but it is necessary to add “dither” (a small error intrucks (ADTs) is the direct reduction of labor costs. Penman truck path control so that the truck does not always follow(2002) found that for two-axle dump trucks in the 220-t (met- the exact same path on the road for every trip, thus caus-ric tons) class, labor accounts for approximately 25% of oper- ing wear over a broader surface of the road) to the steeringating costs, fuel approximately 45%, and tires approximately action to distribute road wear.30%. For the larger, 300-plus-t class truck, Penman found the A central control computer manages the ADTs on aapproximate cost split is labor 15%, fuel 30%, and tires 55%. particular haul. Each ADT continuously communicates keyOther benefits include improved safety through the removal data (position, speed, and heading) back to the central con-of operators from hazardous areas and reductions in machine trol computer, which provides general haulage managementduty (rate of accumulated damage), and fuel consumption including tracking each truck’s trajectory and anticipatingthrough more consistent operation. For example, the world’s collisions. An onboard safety and collision-avoidance sys-first fully automated straddle carrier system at the Port of tem based on millimeter-wave radar and laser-sensing tech-Brisbane has reduced energy costs per container move by 40% nologies is used. This system has an overriding authority to(Kalmar Industries 2007). bring the truck to a stop if an obstacle or safety hazard is The enabling technologies (navigation, truck control, detected.and collision detection) for ADTs exist in a semimature form,and prototype ADTs integrating these technologies have been Automated Underground Loading and Haulagedeveloped and tested. Commercial ADT systems are not yet In underground mines, the restricted environment in whichavailable. Of the major haul truck manufacturers, Komatsu equipment operates has aided in its automation. In addition,and Caterpillar have both developed and demonstrated auton- some of the greatest potential hazards to miners occur whenomous dump truck technologies. operating in and around underground mobile equipment. This Komatsu currently has two sites operating its ADT tech- was an early driver to automate primary underground mobilenology, called FrontRunner. Codelco, at its Gabriela Mistral materials handling equipment. Load-haul-dump units (LHDs)
  5. 5. Automation and Robotics 809and trucks operating underground follow well-defined routes function of the individual task needs, such as the followingin repetitive operating cycles. These, coupled with a well- examples:structured underground operating environment, made deploy- • Adjusting ripper depth and angle, and dozer speed andment of early autonomous vehicle technologies feasible. As direction, to ensure good ripping performance is key forearly as 1988, King (1988) predicted a positive economic an automated ripping dozer. Here, interaction with otherreturn for the use of semiautonomous LHDs. Caterpillar machines is often limited.Global Mining (2008) describes recent trials of automated • In many cases, dozers create structured profiles for otherLHDs at the Malmberget mine in Sweden showing an increase machines to work on or from. Here, material movementin productivity of between 10% and 20%. accuracy may be important. Autonomous LHDs and underground trucks are now • Dozers that undertake utility work such as dragging pipesavailable from several manufacturers. These are the Caterpillar and cables, moving power boxes, and pushing scrapersMineGem system (Caterpillar Global Mining 2008), Sandvik’s may have dedicated sensors and automation capabilities.AutoMine system, and Atlas Copco’s Scooptram Automation Here, the dozers require the ability to rapidly move fromsystem. At this time, more than 10 mine sites worldwide are one application to another.operating or plan to operate either or both autonomous LHDs • Interaction with other machines, and detecting whereand underground trucks. These include De Beers’ Finsch and what to clean up, is important for dozers requireddiamond mine in South Africa (Faurie 2007), Codelco’s El to undertake cleanup tasks. An automated dozer wouldTeniente mine in Chile, and the Stalwell gold mine in Australia have to detect when and what to clean up and interact(Caterpillar 2007). with other machines (shovels, trucks, etc.) in a variety Both systems have the underlying premise of removing of modes.the operator from the machine to a remote operating station,where the machine can be teleoperated. This station could The automation of dozers to remove operators frombe located underground, on the surface at the mine site, or machines appears feasible for dozer operations where interac-at some distant location. Operation requires onboard cam- tions with other machines is limited, and complex sensing anderas, computer control of machine functions (steering, brak- recognition of subtle changes in the machine’s environment areing, acceleration, bucket motions [LHDs], etc.), high-speed not required. These cases do not require development and usenetwork communications, and associated safety systems. of complex sensing systems, advanced automation infrastruc-However, simple teleoperation is stressful for operators and ture, or control of complex machine–material interactions.less productive than manual operation. Automated dozers are not commercially available today. The solution is operator-assisted automated steering Several original equipment manufacturers (OEMs) and third-during teleoperation. Here the operator does not physi- party providers have GPS-based dozer operator aids. Thesecally steer the system but views the machine’s location in include, from Caterpillar for example, “an in-cab display thatreal time on a mine plan (typically on a computer screen) gives operators easy to understand color diagrams of whereand then uses a joystick to give the machine the direction to cut and fill. The system uses onboard computers, software,of travel. In Caterpillar’s MineGem system, this is called data radios and centimeter-level GPS receivers to constantlycopilot mode. monitor work and update the plan” (Caterpillar 2006b). Finally, in autonomous mode the remote operator pro- Remote-control solutions have also been available for dozersvides a goal for the machine (LHD or truck) and the self- for many years. These are typically retrofits by third parties.guidance system controls the vehicle. In Caterpillar’s Research into better solutions for remote-control dozersMineGem system this is called autopilot mode. Typically, the continues. A recent project funded by the National Instituteoperator fills the LHD’s bucket in remote mode and then enters for Occupational Safety and Health in the United States devel-autopilot mode to tram to the dump point, empty the bucket, oped a remote vision system for dozers on coal stockpiles.and return to the loading point. Thus, in autopilot mode, sev- The project involved Consol Energy and Caterpillar as par-eral machines can be operated by a single operator. For safety ticipants. This work is described in Schiffbauer et al. (2007).reasons, remotely controlled and autonomous machines need Many of the enabling technologies (dozer control, posi-to operate in exclusion zones that strictly control access. tioning, and navigation) for automated dozers have been used The key to operator-assisted automated steering and in remote-control applications for some time and thereforeautonomous navigation for LHDs and trucks is the use of exist in a semimature form. It is expected that automated doz-a laser–radar range-sensing system. This system maps the ers with the complete capability to build profiles, clean up,location of objects (typically walls) around the machine and and rip will be achievable in the next 5 to 10 years.determines their location by comparing the measured profiles Dessureault et al. (2007) and Holmes (2006) describe anto an existing database provided from the mine map. This automated dozer project at Freeport-McMoRan’s San Juantechnique is known as simultaneous localization and map- (Arizona, United States) test site. The target application forping. Thus, knowing the location on the map relative to the this dozer is ripping. The dozer sensors include GPS, Sicknearest walls, the control system can drive the LHD to the lasers, and cameras (for teleremote operation).desired location. Automated Blasthole DrillsAutomated Dozers Automated blasthole drills (ABDs) have the potential to gen-Dozers are typically used for a wide range of applications in erate a number of benefits. These includemining. These include profile construction, cleanup around • Reductions in machine duty (rate of accumulated damage)other machines, ripping, and utility work. Thus the level through smoother computer-controlled operations, andof complexity required to automate a dozer is very much a
  6. 6. 810 SME Mining Engineering Handbook improved blasting performance through more accurate Remote Operations Centers and consistent drilling; A remote operations center (ROC) enables supervision, con- • Reduced labor costs; and trol, analysis, and data acquisition from afar. In simplest • Improved safety through removal of the operator from a terms, an ROC can be regarded as a platform for enabling hazardous and dusty environment. process automation and business integration. An ROC enables Automation can also optimize drilling performance • Enhanced occupational health and safety by removingthrough control of bit loading, drill rpm, and torque param- operators and maintainers from risk exposure;eters. Increased penetration rates, lower bit wear, and reduced • Reduced labor costs by relocating high-cost, knowledge-drill costs will result. It is also desirable that holes are drilled at intensive labor away from mine sites to urban centers;locations specified by the designed blasting pattern. Inaccurate • Increased productivity throughholes can lead to poor blasting fragmentation, inappropriate – Identification of inefficiencies at operating interfaces,muck-pile shape for loading, and so on. – Collaborative planning between functions (operations, ABDs also have the potential to generate benefits that maintenance, and procurement),include implementing drill-based, high-level rock recognition – Sharing of experience and knowledge across minesystems to provide detailed rock type and structure informa- sites,tion that can be used in blast design. Consistent drill operation – Process visibility along the process chain; andthrough computer control of the drilling process enables these • Potential to lock in benefits through knowledge capturesystems to operate effectively. and reuse. Thus, the enabling technologies (navigation, drill control, Implementing an ROC provides an important catalystand remote control) for ABDs have existed in a reasonably for change within an organization. Current workflow patternsmature form for some time. Prototype ABDs integrating these must be evaluated and modified or adapted. Implementingtechnologies are currently under development. Holmes (2006) ROCs therefore provides an important stimulus for changingdescribes the development in 2005 of an automated blast- work practices and driving an organization to achieve higherhole drill called the Advanced Rotary Drill Vector Automated levels of labor productivity.Radio Control (ARDVARC). Holmes states, “Preliminary Interest in applying ROCs is growing within the min-results of ARDVARC trials as compared to normal manual ing industry. Examples of early adopters within the miningdrilling operations has shown a +15% productivity gain, industry are Rio Tinto Iron Ore (RTIO) in Western Australiaimproved pattern and hole quality, and lower machine duty and Freeport-McMoRan in their Arizona (United States)cycle. Additional gains achieved from hole-to-hole position- operations.ing are expected.” The technology was tested on a BE49R drill Schweikart (2007) outlines the business drivers forbut has been transferred to the Atlas Copco PV271 drill. RTIO’s implementation of an ROC: Rio Tinto has also been developing an automated blast-hole drill that is currently operating at its West Angelas iron • High cost of supporting remote staffore mine. (The outcomes of this project are described in detail • Desire for increased staff retentionlater in this chapter.) This machine is designed to drill auto- • Business integrationmatically in both rotary and rotary-percussion modes. In addi- • Faster, better decisionstion, the drill is capable of performing rock recognition during The ROC will also supervise the autonomous systemsthe drilling process in order to build a rock mass description operating at RTIO’s West Angelas iron ore mine site. A fleetof the area to be blasted. This description is then used in the of five autonomous 320-t Komatsu haul trucks are operatingblast-design process. This drill also has full video remote- at West Angelas, as well as one automated blasthole drill rigcontrol capabilities. (Trounson 2007). The typical attributes of autonomous blasthole drills cur- The removal of the need to maintain a large work forcerently under development are on-site saves ancillary camp expenses; remote working allow- • Automatic drilling of the hole from collaring though pipe ances; and fly-in/fly-out expenses, which can account for sig- removal when either manned or autonomous; nificant costs. Additionally, integration of operations (site, • Navigation from hole to hole within a drill pattern; transport, and infrastructure) in one center removes “silo men- • Completion of drill pattern autonomously including accu- tality,” where people are focused only on the component of the rate setup, relocating holes (due to hole failures or impos- operation they are involved in and fail to see the effects on the sible collaring), inclined holes, and drill bit changes; whole mining process, creating bottlenecks at interfaces. • High-level task instructions from a drill-and-blast Improved telecommunications infrastructure, in par- management system; ticular telephone networks and fiber-optic links, are cited • Monitoring of self-condition (e.g., airflow and pressure, by Dicker (2007) as key technology enablers for the ROC oil pressures, rpm, component failures) and appropriate development. RTIO is evaluating the remote support of reaction (e.g., report bit failure back to drill-and-blast maintenance personnel via head-mounted displays and management system); wearable computers. Support would make extensive use • Monitoring of drill parameters (thrust, rpm, vibration, of video conferencing, remote desktop access, and voice- and other active and passive geosensors) and using this over IP technologies. RTIO is also evaluating remote col- information for rock-recognition information that can be laborative planning via the use of augmented reality (virtual fed into a drill-and-blast design system; and reality based on real sensor information) and touch tables • Video remote control of all drilling functions. (Schweikart 2007).
  7. 7. Automation and Robotics 811 Schweikart outlines a 4-year plan to achieve remote- Capabilities of the Autonomous Diggerintegrated operations. The first step of this plan is to integrate The autonomous diggerdisciplines (planning, operations, and maintenance functions) • Excavates material and loads trucks with minimal humanat site level, and to begin the transfer of people from site to intervention;ROC. The second step is integration per asset (site operations • Plans and executes repositioning moves using high-levelintegration) through the transition to remote operation and mission statements referenced to the mine plan;deployment of operations models. The third step is integration • Feeds up-to-date information garnered from onboard sen-across sites. Because of safety concerns and relatively static sors back to the mine plan including terrain information,operating environments, it is likely that ROC technology will material diggability, and productivity indicators;be implemented first on fixed assets, such as beneficiation • Manages the dig face and floor to optimize productivityplants. and maintain favorable bench structure; RTIO is investing particular attention to aspects of change • Automatically executes ancillary functions includingmanagement and reevaluation of workflow. Scweikart empha- management of the trailing cable (on electric shovels),sizes that changing to a remote supervision and operations machine park-up for access, and so on;model necessitates a change in the way that work and informa- • Has advanced status monitoring capabilities to identifytion flow is managed, and that replicating existing workflows situations associated with the machine or the environ-may not improve productivity. ment requiring attention. This includes monitoring struc- Coyle and Holmes (2007) indicate that the installation of tural and electrical heath trends for early prognosticationFreeport-McMoRan’s ROC on-site was justified on the elimi- of events and failures;nation of inefficiencies across operational boundaries. The • Manages overall activity in the load area including theROC is also seen as playing an important role in “institutional- scheduling and dispatch of trucks, cleanup activities, andizing the knowledge” of maintenance and operations experts. so forth; andHere, the vision of the future has tactical operations personnel • Provides an information-rich teleoperation mode thatco-located in a “room of truth.” Verified information is made allows recovery from exceptional situations to be com-available on a real-time basis so that subject-matter experts pleted remotely.can assist less-skilled operatives in the field. Crosspollinationof ideas and shared operational awareness are forecast to lead Benefits of the Autonomous Diggerto significant efficiency gains for the organization. The benefits of the automated digger stem from the increased consistency and reduced variation that automation brings toAutomated Digging equipment operation, resulting in productivity and reliabilityLarge-capacity shovels and hydraulic excavators (called diggers improvements and the ability to have the machinery operatein this section) with bucket capacities to 70 m3 are critical pro- under its most favorable conditions. Ultimately this translatesduction units at most open-cut mine sites, and there is an ongo- to increased productivity with lower production costs anding imperative to improve their productivity. Automation is seen energy consumption.as one of the strategies by which improvements can be realized. The business case for the autonomous digger is likely to The automation of diggers presently stands at an interest- be built around the following benefits:ing nexus. Most of the technology needed to realize the auto-mated digger exists (albeit at varying levels of maturity), and • Consistent and accurate loading of haul trucks. Whendevelopments in other sectors, including industrial robotics trucks are loaded to their rated payloads and the loadand the automotive and aerospace industries, are delivering is correctly distributed across the tray, then the chassis,further advances that enhance technical feasibility. transmission, and tire life are significantly improved and However, the cost and risk of introducing automated dig- operating costs reduced.gers to mining operations currently outweighs the perceived • Increased digger availability. Automation brings con-benefits. An automated digger must operate as part of the sistency that stands to increase equipment availabilityoverall operation of a mine with implications on mine infra- through lower duty loadings.structure, operational practice, work-force skills, and site cul- • Safer operation. Most safety incidents associated withture. The gap is significant and no mining company is actively diggers are linked to operator error (e.g., digger–truckpursuing the introduction of automated diggers to their opera- collision). By marginalizing the root cause, automationtions, notwithstanding the several significant mine automation has the potential to reduce the frequency of accidents andinitiatives taking place worldwide (e.g., Rio Tinto’s Mine of near misses.the Future at the West Angelas mine site). The transition to automated diggers will likely occur over Technology Gapsthe next 20 years. It will almost certainly be staged through Four broad technology gaps must be bridged to realize theincremental stepping-stone technologies that, in themselves, autonomous digger:bring productivity and reliability benefits and allow the risks 1. Control strategies must be developed to enable automatedto be understood and controlled and the technology to mature machines to operate interdependently with other equip-and be proven and accepted in mining environments. ment (manned and automated). This section attempts to identify, at a fairly high level, 2. Situational awareness capabilities must evolve to the pointautomation capabilities that might serve as planks in the bridge where they can replace the many and varied functionsto realizing the autonomous digger over the next two decades.
  8. 8. 812 SME Mining Engineering Handbook Machine Situational Shovel Automation Load Area Situational Awareness Capabilities Capabilities Awareness Capabilities Automated load-area management 2025 Automated excavation systems, including digger repositioning Load area situation awareness covering and optimal dig planning perception of the layout of and equipment operating in the load area, and comprehension of other equipment Automation support functions (e.g., activity and the projection of this activity trail cable management for electric Into the near future shovels, automated park for access, etc.) Teleoperation/remote machine 2020 Bilateral fusion of spacial terrain operation incorporating information with the mine map shared mode control Automated machine cycle—dig, swing, load, dump Fit-for-purpose site visualization of load area activities suitable for Identification of automation-critical Automated swing loading— remote operation of diggers machine faults (e.g., failed dipper trip) automation of the swing, dump and return phases of machine cycle External collision avoidance 2015 systems that avoid collisions Automated identification of roads, with bank, trucks, etc. cable bridges, rock spillage, trail Automated structural health cables, berms, etc., In terrain maps monitoring and prognosis Dig assist—tools that assist operator dig more effectively Automated identification of trucks Intermachine data and information and ancillary equipment from Electrical health monitoring sharing frameworks digital terrain maps and prognosis 2010 Digger self-collision avoidance systems (e.g., P&H Trackshield) Shovel geolocation capability— Ranging sensor-based integration of RTK GPS/GNSS, intertial terrain acquisition Intramachine data and information navigation, and onboard sensors to sharing frameworks monitor from where material is excavated Automation-ready machine control system (e.g., P&H Centurion for 2005 Productivity monitoring tools—payload, P&H shovels) cycle times, dig energy, etc. Established Under Future Capability Development DevelopmentFigure 9.8-1 Autonomous digger capability plan to 2025 currently performed by human operators in planning and integrate their proprietary systems by ad-hoc methods on an actions, and monitoring the status of the machines. as-needed basis under pressure applied by the end user (the 3. Technologies are required that enable effective integra- mining companies), or one provider will come to dominate the tion of automated machinery into mine systems. market and set a de facto standard for integration. 4. Work-force skills must be enhanced to support deploy- The long time horizon for achieving a fully automated ment of high-end automation technologies. digger system mandates a multigenerational technology plan with commercial outcomes that prove technology com- A significant component of the shovel automation prob- ponents and support and maintain the development effortlem is systems integration, including management of interac- toward its end goal. Figure 9.8-1 gives a digger automationtions with trucks and other equipment and integration of the capability plan to 2025 with capabilities divided into threeautonomous shovel into the mine plan. Although in the long categories:term there will, almost certainly, be multiple technology pro-viders working to agreed automation standards, at this time the 1. Machine situational awareness capabilities. Theseproblem is not sufficiently well defined for effective standard- include such things as machine performance monitoring,ization efforts. The likely scenario for the short-to-medium functional safety capabilities support automation require-term is that various equipment and technology providers will ments, electrical and structural health monitoring.
  9. 9. Automation and Robotics 813 2. Shovel automation capabilities. These incrementally autonomous LHD products, but not for large-surface loading build from operator assists such as collision-avoidance machines. A considerable body of research in automated dig- tools through automated digging to management of the ging exists. Singh (1997), Hemami and Hassani (2009), and load area. Lever (2001) provide reviews of this research area. 3. Load area situational awareness capabilities. These build an evolving richer situational awareness model of Longwall Automation the load area with knowledge of digger and truck posi- Two basic control systems exist in a longwall operation. One tioning at the lowest level, building toward the full per- control system operates in the horizontal plane to control the ception of elements in the load area, the comprehension plan-view geometry of the longwall face, and the second oper- of their meaning, and the projection of their status in the ates in the vertical plane to control the roof- and floor-cutting near future. horizons within the coal seam. Added to these functions are systems for armored face conveyor (AFC) control, including Implicit in this capability map is that machine and load chain tensioning and load sharing, and shearer haulage control.area situational awareness capabilities feed into shovel- In simplest terms, in plan view, the longwall face shouldautomation capabilities. The timeline is indicative as is the be straight and perpendicular to the gate roads. If the face isordering, but it is generally expected that capabilities will flow straight, both mechanical stresses on the armored face con-in this order. veyor and roof support geotechnical issues are minimized. The plan has been organized so that each identified capa- The process to achieve this situation is known as face align-bility could, in principle, serve as a commercialized outcome. ment. As the longwall retreats, the assembly of supportsThe continual delivery of technology products that have pro- should not creep toward either main or tailgates. To achieveductivity or maintenance benefits in their own right and con- this result in practice, often the face line is angled, introducingtribute incrementally to the autonomous digger represents the so-called tailgate lead or lag with respect to the main gate soonly practical strategy. R&D-based innovation at all levels of that in sloping seams, the same creep-minimizing result canthe plan is strongly needed, and the most likely scenario is be obtained. Managing the lateral position of the longwallthat R&D will be completed by consortiums made up of an equipment in the panel is called creep control. Automatic faceequipment manufacturer, the end user, and one or more third- alignment and automatic creep control are two functions thatparty technology providers including research organizations can be applied to effectively provide automation of longwalland universities. plan view geometry. Available systems are discussed in this section.Current State of Automation In the vertical plane, the automation situation is moreFully automated shovels are not commercially available. complex. The goal of the longwall, similar to any miningHowever, shovel automation has been the focus of extensive operation, is to maximize extraction of product and minimizeresearch over the past few years. Dunbabin and Corke (2006) extraction of waste. This means the longwall shearer shoulddescribes automation work completed on a 1/7-scale model operate so that roof- and floor-cutting horizons are entirelycable shovel that demonstrated the ability to automatically within the seam, or in some cases within a selected band withinperform multiple truck-loading passes that included excava- the seam. Achievement of this goal is known as horizon con-tion of the dig face, swinging with obstacle avoidance, iden- trol. Automated horizon control needs to at least emulate andtifying an awaiting truck tray, determining an optimal loading at best entirely replace human-operator strategies for steeringstrategy, and dumping the material. the shearer within the seam. Again, the available automation McAree et al. (2007) describe collaboration between the solutions for horizon control will be discussed.Cooperative Research Centre for Mining (CRCMining) and Undeniably, longwall automation has the potential toP&H to develop advanced technologies leading toward shovel deliver significant advantages in both productivity and safetyautomation. A P&H/CRCMining laboratory has been set up in (Henderson 2007). Interruptions to the mining process area quarry north of Brisbane, Australia, and includes a full-sized basic causes of decreased productivity. Continuous automaticP&H 2100BLE electric cable shovel. This laboratory is used face alignment, for example, can virtually eliminate stop-to develop and evaluate technologies that increase the produc- pages caused by current string line–based manual alignmenttivity of electric mining shovels. processes, and optimal alignment of AFC components mini- The Australian Coal Association Research Program mizes wear and reduces consequent equipment breakdown or(ACARP) is currently funding a project to develop, to proof- change-out delays. Close control of face geometry can alsoof-concept, an automated swing-loading technology for elec- improve geotechnical performance of the roof-support systemtric mining shovels at this facility. A joint CRCMining and where an automation system can ensure that shields are setAustralian Commonwealth Scientific and Industrial Research consistently.Organisation (CSIRO) team are developing technologies for a Automatic horizon control can more effectively steer theshovel that cycles the swing, dump, and return functions. This longwall in the seam to minimize product dilution and can alsoincludes automatically identifying the location of a truck or contribute to more-effective strata control by accurately leav-in-pit crusher–conveyor to be loaded; planning and executing ing coal on the roof and/or floor to protect weaker strata. In thea minimum path from dig to dump location without the dip- safety context, automation provides the ability for the mine toper colliding with the truck, crusher, or bank; and dumping remove people from hazardous areas, minimizing exposure towithout spillage and swinging back to tuck position for the dust, heat, noise, and danger from roof and face falls.next dig. Automated digging is probably the most complex com- Automatic Face Alignment and Creep Controlponent of loader automation. Automation technologies to Automated face alignment is now a mature technology, andassist digging are commercially available for several of the all longwall roof support manufacturers offer systems that
  10. 10. 814 SME Mining Engineering Handbookdeliver effective face alignment automation solutions. These It is difficult to accurately quantify productivity benefitssystems allow desired face profiles to be entered into shield- due to contribution from specific automation system ele-control systems through appropriate graphical user interfaces, ments. However, in the case of LASC-based face alignment,and shield-control systems are capable of moving individual sustained productivity improvement of 130 t/h was reportedshields by calculated distances and are thus also able to coor- (Reid 2008). Other productivity improvement information isdinate the motion of assemblies of shields to achieve desired company-confidential to individual equipment suppliers.profiles along the entire face. Shield hydraulic control systemshave been enhanced to allow accurate control of double-acting Automated Horizon Control(D/A) ram motion, and sensors to reliably measure D/A ram Longwall horizon control—manual or automated—is a chal-travel have been incorporated into shield designs. lenging task. Whereas the overall goal of horizon control is to Until recently, the major defect in automatic face align- ensure that as far as possible only coal is extracted, there arement has been the inability to automatically and reliably mea- a multitude of site-specific considerations that detract from asure the actual geometry of the longwall. True closed-loop mine’s ability to achieve that goal. It might not be possiblecontrol of face alignment can only be achieved by comparing to detect seam boundaries effectively in order to prevent thethe physically measured location of the face with the target shearer drums from cutting surrounding rock. In the case oflocation and then minimizing the resultant error. Previous thick seams where visible or other cues to indicate seam tra-methods were largely based on measuring the accumulated jectory are absent, it is difficult to steer on a consistent pathmotion of shield D/A rams to indicate face geometry, which between the gate roads. In other cases, seam undulations alonggave only an approximate solution with increasing accumula- the face or into the panel might mean that equipment cannottion errors. This situation has been remedied recently through articulate sufficiently to track the actual horizons, and roof orthe development of the LASC (Longwall Automation Steering floor is cut as a consequence. Problems in detecting fault con-Committee) technology, which measures three-dimensional ditions ahead of mining could mean it is necessary to mineshearer position directly through an inertial navigation-based through the faulted zone at short notice.SPMS (shearer position measurement system). Because the Automation of horizon control is in the developing stages.shearer actually cuts the face, direct measurement of shearer The most successful strategy so far has been based on trainingposition is the best indicator of face geometry. Open speci- an automation system using a human operator employing tra-fications for SPMS data outputs have been devised enabling ditional manual cues for horizon detection and control to steerLASC technology to be applied to any combination of face the shearer. The learned extraction process is then repeatedequipment. The reader is referred to www.lascautomation.com automatically until some departure from the horizon-controlfor details of LASC specifications and more-detailed LASC strategy is observed, such as roof or floor being cut. The train-technology descriptions. All face equipment manufacturers ing process is then repeated. The advantage of this process isnow offer LASC technology to the market. that operator exposure to face conditions is at least reduced. Sensors that measure the position of longwall face equip- The accuracy of this process has been improved by the avail-ment relative to the gate-road ribs can be used to provide a ability of the LASC technology, which gives high-accuracymeasure of automatic creep control. If motion of gate-end floor-horizon measurements. All shearer manufacturers offerequipment relative to the ribs is detected, appropriate lead or systems that are variations on this basic strategy.lag of the face can be introduced into the basic face geometry The next stage in the process is to use sensors that caninput to the automation system. Although LASC laser-based replace the horizon-sensing capability of human operators,creep sensors are now available to provide this measurement, or bring to bear new horizon-sensing results. Coal interfacetransformation of this information directly into tailgate lead or detection (CID) sensors based on natural gamma emissionlag values is highly site dependent and requires operator input. by surrounding strata, thermal infrared detection, ground- penetrating radar, optical marker band tracking, and otherFace Alignment Control System Example methods have been developed with varying results. The onlyContemporary graphical user interfaces (GUIs) for longwall commercial CID sensors currently available are based onroof support control systems can be used to display the state natural gamma radiation and detection of electromagneticof sections of a complete longwall face that can exceed 200 propagation differences between coal and surrounding strata;shields in current operations. They can also display the leg several of the other methods are still in the research stage.hydraulic pressures. This display gives immediate information Figure 9.8-2 shows a GUI for an interactive automatedregarding the hydraulic performance of the supports and can horizon control system based on the LASC technology. Thealso show through color change when particular shields are not GUI accepts and displays horizon information over the fullset correctly or are being excessively loaded by the roof strata. face length. The upper screen enables an operator to enter When the face has become misaligned with respect to adjustments to a nominal extraction-height setting that hasthe target face line, it is seen as an uncut wedge develop- been independently set in the shearer control system. The flating between the desired profile of the unmined coal and the line shows that no operator adjustments have been selected.AFC. To realign the face, a wedge cut must be executed in the The lower screen enables the operator to view recom-current shearer run to realign the supports perpendicular to mended floor profiles and to input adjustments manually. Thethe longwall block. This is achieved by making proportional system then automatically generates LASC-recommendedchanges in the shield advance distances programmed to intro- floor-height adjustment for the next complete shearer run. Induce a compensating wedge shape in the face, eliminating the its simplest form, this adjustment is generated by extrapolat-misalignment as the shields advance after the shearer passes. ing the average floor profile from the previous five shears. AtThe success of this kind of control depends on accurate mea- this stage of development of automated horizon control, thesurement of face profile and D/A ram extension as outlined in operator is in the loop. The operator has the ability to inputthis chapter. manual floor-height adjustment on a per-shield basis.
  11. 11. Automation and Robotics 815 Courtesy of CSIRO Division of Earth Science and Resource Engineering. Figure 9.8-2 A prototype automated horizon control system user interface The operator’s task is to input manual horizon inputs to consistency that was possible when operation was based on amatch the recommended profile as closely as possible. The fixed programmed sequence and not subject to variable opera-operator is also able to take into account off-system inputs tor inputs.such as physical observations along the face or known condi-tions that would preclude the shearer being able to execute the Challenges to Overcomeautomation system’s recommended track. Close matching of The automation technologies described in this chapter are ablemanual to automatic settings is shown on the left-hand side of to successfully automate the routine operations of a longwall.the display in Figure 9.8-2. On the right-hand side, the opera- The major problems encountered in longwall automation aretor has chosen a floor profile that does not closely follow the concerned primarily with the management of exceptions topredicted floor alignment. normal operations caused by the fact that an underground Figure 9.8-2 shows the smooth profile that the automation mine is actually not a factory environment and is subject tosystem generates compared to the manual inputs. This profile the vagaries of nature. To achieve full automation and thethen becomes the floor-height adjustment target for the OEM’s “workerless face,” many more sensors need to be developedshearer-control system. to replace the observing roles carried out by face operators at present. Additionally, there are issues with ensuring that“State-Based” Shearer Automation equipment operates to the standards required for automationIn recent years, one of the most successful initiatives has in a harsh, hazardous environment.been the development of programmed shearer automationon a logical state basis. The concept is similar to the train- Mine Requirements for Longwall Automationing method of horizon control described earlier. The operating The face alignment and programmed shearer automation sys-parameters required for the shearer to completely execute a tems can be implemented in most mines. In the case of hori-single pass of a particular cutting sequence are defined as a zon control, it is necessary to establish whether local seamseries of logical states that encompass combinations of rang- conditions exist that allow horizon sensors to be effective.ing arm positions, haulage speeds, and various sensor outputs Equipment manufacturers can offer advice as to which sen-including motor currents, position measurements, and so on. sors will be appropriate.As the shearer travels along the face, it sequences through the For modern automation systems, high-quality data com-previously defined states. If no anomalous states are encoun- munications links to sensors and face equipment are required.tered, the pass will be executed successfully and the machine Longwall manufacturers now provide Ethernet connectivitywill commence the next pass. Error states can be defined to on face equipment as a matter of course. For these systems tohandle operational exceptions, but some errors will cause the be effective at a mine, corresponding communications infra-system to halt when human intervention is required. When this structure must be available between the face, the surface, andsystem was first introduced, significant productivity improve- wider into the mining company’s and its service providers’ments resulted immediately. This was attributed largely to the data communication networks.
  12. 12. 816 SME Mining Engineering Handbook Optimal longwall automation results can be achieved hence the angle the bucket-rope plane made with the verticalonly if all elements in the mining process are operating reli- boom plane (Roberts et al. 1999).ably and at peak performance. Automation systems requireparticular attention to engineering and maintenance standards Automation of BE1370 Dragline Demonstrationat the mine to ensure that all components of the system are A full-scale proof-of-concept automated swing-control sys-effective. An automation culture must be developed and main- tem was developed on a BE1370 dragline at the Tarong coaltained in the work force so that automated operation is funda- mine in South East Queensland, Australia. It performed a fullymental to production. automatic dig-to-dump-to-dig motion, whereas bucket filling remained the responsibility of the operator. A key componentDragline Automation of the system was active controls—the joysticks and pedalsThe rate of overburden removal is almost always the bottle- were driven by small motors to affect computer control ofneck in open-cut coal mining, and draglines (the most cost- the dragline, but the operator could override at any time andeffective means of overburden removal) are the tools of regain control by moving one of the joysticks. This systemchoice. To address this production bottleneck, various strate- was further developed on a BE1350 at the Boundary Hill pit ingies have been adopted. First, manufacturers have increased in central Queensland, where in 2002 a 2-week production trialsize and power over the past 40 years, but there appears to be was undertaken (Corke et al. 2003). In total, 12,235 cyclesa physical limit in just how large these machines can become were performed, 3,042 using the automation system and 9,193before they are impractical. Second, mines have put substan- fully manually. More than 250,000 t of material were movedtial effort into operator training and production monitoring autonomously during this trial. In summary, three significantwhile also routinely overloading the machines. These strate- conclusions were reached. First, the system performed moregies are unable to yield further improvement, but continually than half of its cycles in better time than the average of theincreasing stripping ratios (which have increased from 2–5:1 operators working over that period. Experienced operatorsto 8–15:1 today) mean that the need is still acute. observing the dragline could not tell a manual cycle from an Automation is therefore increasingly seen as the next automatic one. Second, the performance of the automationphase in the evolution of the dragline and the industry’s quest system was compromised by the system’s lack of accurate ter-for increased production. In addition, many in the industry rain information. The system relied on the operators markingbelieve that automation can also offer the possibility of lower the position of the spoil piles, highwall, and any other obsta-maintenance costs through the control of the machine within cles. This was done by placing the bucket over these locationsits design limits (a task that human operators often struggle and pressing a button on the joystick controller. However, awith). Finally, automation systems can deliver consistency and safety margin was introduced to ensure that the bucket neveran equivalent skill level that can result in a system that overall collided with the terrain, and this typically added a 5%–10%will outperform human operators—it may not be as fast as time penalty to each automated cycle (due to overhoisting).the best operator at the beginning of a shift, but because of its Third, it was clear that the automation system treated the drag-consistent operation, it will on average outperform the pool line more gently than the human operators. No specific main-of human operators. Automation further promises a means of tenance benefits could be derived from such a short trial, butovercoming this skill shortage and would seem inevitable in the time history of control outputs from the automation systemthe mining industry. were far smoother than the human operators. The same CSIRO team between 2002 and 2006 addressedAutomation Development the lack of real-time situational awareness around the draglineThe history of dragline automation can be traced back to the where they developed a digital terrain mapping (DTM) sys-late 1980s when BHP Billiton performed a series of trials at a tem. As well as allowing an automation system with a smallermine in central Queensland, Australia (Allison 1992). These safety margin, the accurate knowledge of terrain can be usedtrials attempted to show that a dragline could be partially auto- by the automation system to plan optimal bucket trajectories.mated by replaying the control signals of an experienced oper- The successful use of 2-D laser scanning systems for ropeator. However, one of the conclusions of these trials was that location (Roberts et al. 1999) inspired the CSIRO research-the instantaneous swing angle of the bucket beneath the boom ers to trial a longer-range scanner on the boom tip, giving itmust be taken into account, making the simple replay strategy a view of the terrain immediately beneath the boom. Withinfeasible; that is, there must be some kind of bucket swing this arrangement, all the terrain around the dragline could befeedback into the control system. In 1993, CSIRO researchers mapped as the machine rotated (Roberts et al. 2003). Initialfunded by the mining industry began to investigate bucket- standalone trials (without the automated swing control) provedswing sensing and the subsequent automatic control of a the concept, and a 4-week production trial was undertaken indragline’s swing motion. Initial experiments determined that 2006 on the Boundary Hill BE1350. A DTM produced dur-vision systems, touted at the time as the solution to the bucket ing this trial is shown in Figure 9.8-3. This trial showed thatswing-angle sensing issue, could not operate around the clock DTMs could be produced routinely in a production environ-in the adverse weather and visibility conditions typically ment and that the DTMs themselves were useful to the mineexperienced at mines. Instead, these camera-based prototypes planners and surveyors, even without an automated draglinewere replaced by two-dimensional (2-D) scanning laser range control system. Further, a level of detail never envisaged wasfinders, which became commercially available in 1995. These obtained in that the material movement of every cycle couldsensors proved to be very robust and adaptable to the weather be recorded if desired.and lighting conditions as well as the mechanically harshenvironment experienced at the end of a dragline boom where Automated Dragline Digging and Precision Dumpingthey were mounted. With such a system it became possible In 2005, the CSIRO team demonstrated a fully autonomousto accurately measure the swing angle of the hoist ropes and tenth-scale model dragline that incorporated bucket-swing

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