Analysis of U.S. surface mining haul-truck-related fatalities

Powered haulage and haul-truck-related fatal accidents are among the most frequent at surface mines. Industry organizations have developed guidance on accident scenarios to address haul-truck and mobile-equipment, collision-related accidents. However, there is a need to investigate accident data to prioritize these scenarios and identify factors relevant to developing validation methods for collision warning/avoidance technologies and determining their capabilities and limitations. Standards and effective validation methods are necessary to improve system efficacy within mining operations and to promote industrywide adoption. To address these needs, researchers from the National Institute for Occupational Safety and Health (NIOSH) investigated available powered-haulage and machinery-related fatal accident reports documented by the U.S. Mine Safety and Health Administration (MSHA). The objective was to gain a perspective for developing test protocols and validation methods by determining the most prevalent accident scenarios in surface mines and related factors. The findings offer insight into addressing the most prevalent haul-truck scenarios within U.S. surface mining environments. In 2018, MSHA published a proposed rule and request for information as part of its poweredhaulage safety initiative (MSHA, 2018). This effort placed significant focus on improving safety around powered-haulage equipment, including surface-mine haul trucks. NIOSH researchers began to characterize safety and health-related issues surrounding haul trucks used at surface mines (NIOSH, n.d.). This project produced a research road map that identified validating collision-warning and avoidance systems (CXS) as a priority for haultruck- related research. A separate project was launched to investigate methods for validating the detection performance of CXS for surface-mining haul trucks (NIOSH, n.d.). Background Prior studies have been conducted to assess haul-truck-related fatalities. In 1996, Randolph and Boldt published a report on fatal and nonfatal haul-truck-related accidents from 1986 to 1995 (Randolph and Boldt, 1996). Since then, research conducted by NIOSH has continued to build on that work as new accident reports became available. Turin et al. examined dump-point-related injuries and fatalities from 1988 to 1997 (Turin et al., 2001). Although the researchers in this article discovered that dump-point-related accidents accounted for a small percentage of injuries at surface mines, the findings show these were more likely to result in death or significant lost time than other types of accidents. A study by Kecojevic and Radomsky on loader- and haul-truck-related fatalities from 1995 to 2002 revealed that the most common types of accidents were rollovers and collisions with pedestrians, and the most common root causes were mechanical failure and failure to obey warning signals (Kecojevic and Radomsky, 2004). Another study from Md-Nor et al. on haul-truck accidents from 1995 to 2006 found that mechanical failure was the most frequent cause of fatal accidents (Md-Nor et al., 2008). More recently, Bellanca et al. conducted a bowtie analysis focused on a holistic attempt to understand the causes and general actions that can be taken for lessening haul-truck-related fatalities in the U.S. mining industry (Bellanca et al., 2020, 2021). This study adopted the various levels of defensive control outlined by the Earth Moving Equipment Safety Round Table (EMESRT, 2019). Conclusions of this study allude to the need for the industry to primarily focus on low-level controls (EMESRT levels 1–6) but also suggest that reactive controls, such as CXS (EMESRT levels 7–9), may serve as a supporting line of defense in the mitigation of potentially harmful haul-truck incidents. In 2018, MSHA presented an analysis of collision-warning-system-preventable, mobileequipment- related fatal accidents occurring from 2003 through 2017 at surface mine operations (Wharry, 2018). The analysis included haul trucks, light vehicles and other surface equipment. For haul trucks, fatal incidents typically occurred in the frontal and operator cab areas, and the victims were primarily light-vehicle occupants. This article expands on this research effort and prior work in a study of 54 haul-truck-related fatalities from January 2005 through June 2021 by examining the most prevalent incident scenarios and revealing factors specifically relevant to collision-warning and avoidance-control measures. Methodology NIOSH researchers collected 54 haul-truckrelated fatal accident reports that occurred from January 2005 through June 2021 from the MSHA fatality reports webpage (MSHA, n.d.). The website’s search engine was used to identify accidents that occurred since 2008 inclusive of search criteria for the “location of accident” listed as “facility,” “surface” and “surface of underground,” and “mine categories” for “coal” and “metal and nonmetal.” The search engine does not include accident reports prior to 2008; therefore, fatal accident reports from 2005 through 2007 were individually reviewed to identify accidents that occurred on the surface of coal and metal/ nonmetal operations. Summaries within the respective fatality alerts and preliminary/final reports were reviewed to identify fatalities where a haul truck was involved. For this analysis, a haul truck is defined as an off-road rigid frame or articulated truck chassis that is typically equipped with a dump bed or utility payload (for example, water tank). After the researchers identified the 54 surfaceand haul-truck-related fatal accident reports, each was given a more thorough, in-depth review to summarize various data including the victim(s) location, whether a seatbelt was worn, haul-truck data (year, make, model and payload capacity), hazard-related data (type, scenario, location and speed/direction), date, mine, preliminary report overview and additional information (such as root cause or weather contributing factors). The 54 identified accidents were then classified by type into four categories: pedestrian/ vehicle-related, berm-related, dump-point-related and other-type incidents. The four researchers used a consensus-based approach. Pedestrian/ vehicle-related fatalities include interactions that involve pedestrians, vehicles or other similar objects that are struck by a haul truck moving forward or in reverse and resulting in one or more fatal injuries. These exclude interactions with berms and dump-point features. Accidents classified within this category were further assessed in terms of their relevance to CXS. In terms of being CXS-relevant, each pedestrian/ vehicle-related incident was specifically determined as “yes,” “potentially” or “no,” where CXS technology has clear application, potential application, or no relevance in terms of mitigation and prevention of related events. The berm-related incidents include mechanical failure or loss-of-control incidents that resulted in a haul truck traveling through a berm or boundary and over a high wall, into water or another hazardous area, resulting in operator/ occupant fatalities. NIOSH researchers identified several factors that led to the berm-related incidents including mechanical failure, absent/inadequate berm, loss of control, and impairment of the haul-truck operator. Inadequate maintenance of the haul-truck braking system could be a reason for mechanical failure. Absent/inadequate berm refers to the absence or deficiency of a berm in a hazardous area like a high wall. Loss of control could be the result of speeding, road conditions, inadequate training or a combination of various factors. An impairment of the haul-truck operator could be the result of alcohol and/or drug consumption. A combination of these factors could result in the haul truck traveling through or over a berm. Berm-related incidents were also assessed with respect to how CXS implementation could affect the outcome. Incidents at dump points include situations where a ground failure or reverse over resulted in a haul truck falling or overturning, and consequently the haul-truck operator/occupants being fatally injured. Even though many dump-point incidents involve berms, there are a few differences between berm-related and dump-point-related incidents. Dump-point incidents involve a haul truck backing up to a potential hazard. The operator is usually aware of the berm, which may serve as a visual reference and, if necessary, a contact point to indicate it has been reached (MSHA, 2001). By contrast, in berm-related incidents, the haul-truck operator inadvertently strikes the berm after veering off an intended path. Also, most berm-related incidents occurred while the haul truck was traveling forward. Once the dump-point-related incidents were classified, the researchers identified the main contributing factors in each accident based on information in the report. These factors included absent/inadequate berm, using the berm as a bump stop, undercutting of the stockpile, and not wearing a seat belt. Dump-point-related fatal incidents were also assessed in terms of being CXS-relevant. Finally, an other-type category included the remaining haul-truck-related incidents that did not satisfy the criteria of the previous three categories. The other-type category includes slip/ trip/fall, pinning/crushing of a victim working on a stationary haul truck, fires and other incidents that are not related to collisions, berms or dump points. While the nature of these accidents was irrelevant to CXS, they were included to present a complete overview of fatal accidents involving a haul truck. Results The researchers classified data obtained from MSHA fatal accidents documented since January 2005 through June 2021. A total of 54 incidents involving a haul truck were identified and classified according to incident type as pedestrian/ vehicle-related, berm-related, dump-point-related, or other-type. Using this classification resulted in 13 pedestrian/vehicle-related, 21 berm-related, 12 dump-point-related incidents, and eight incidents classified as other-type (Fig. 1). Figure 1 Incident types for haul-truck-related fatalities. Pedestrian/vehiclerelated incidents. We classified a total of 13 incidents as pedestrian/ vehicle-related having either a pedestrian, vehicle, or similar object that was struck or crushed by a moving haul truck and resulted in one or more fatalities. Figure 2 shows a breakdown of these 13 incidents separated among the four subcategories used within the analysis: pedestrian, light vehicle, haul truck and other. Among these results are five incidents that involved a light vehicle (LV): that is, a pickup truck or passenger van. One of these five incidents resulted in a double fatality and had the potential for additional fatalities. Three involved a pedestrian on the ground in the vicinity of the haul truck, and three involved an interaction with another haul truck. The two incidents classified as other include a collision with a moving railroad freight car, and the crushing of a portable toilet and its occupant. Of these 13 incidents, 12 involved a forwardmoving haul truck that collided with a vehicle, pedestrian or related object in its forward path. The other incident involved a haul truck that backed into another haul truck, crushing the cab and operator who was standing on the deck just outside the cab. Further consideration was given to these 13 incidents in terms of their relevance to CXS; the results are summarized in Table 1. Of these, 10 were identified as CXS-relevant including the five incidents where a light vehicle was crushed by a forward-traveling haul truck. Of these five incidents, two occurred in front of a haul truck that was transitioning from a stopped “idle” state to moving forward, two involved a light vehicle that was parked in the forward path of a haul truck traveling along a haul road, and one involved a haul truck and light vehicle that were approaching each other. It was determined that one of these 13 incidents was potentially CXSrelevant since it involved a loss of control under adverse weather-related road conditions. In this case, it is unclear if CXS technology would have a role in mitigating or preventing adverse interaction induced by road conditions. The remaining two incidents that were determined to be unrelated to CXS involved a stopped haul truck that unintentionally moved or rolled forward and crushed a person on the ground. The 13 pedestrian/vehicle-related collision incidents are summarized in Table 1. Of the 10 incidents identified as CXSrelevant, subject haul-truck payload capacities were distributed among four classification ranges that were defined for this analysis. These are: < 91 t (100 st), two incidents; 91 to 182 t (100 to 200 st), four incidents; 182 to 272 t (200 to 300 st), two incidents; and 272 to 362 t (300 to 400 st), two incidents. It is notable that 40 percent (4) of the 10 incidents classified as CXS-related involved a haul truck with a payload capacity within the 100- to 200-t range. Figure 2 Collision types for pedestrian/vehiclerelated fatal haul-truck incidents. Berm-related incidents. To analyze the 21 berm-related incidents, five subcategories of contributing factors were used: absent/inadequate berm, impairment of the haul-truck operator, loss of control, mechanical failure, and a combination of mechanical failure and absent/inadequate berm. As shown in Fig. 3, loss of control accounted for nine of the berm-related incidents. The second largest contributor to berm-related incidents was impairment on six accounts. Mechanical failure accounted for three, and the absence of berm or inadequate berm contributed to two incidents. One incident came from a combination of both mechanical failure and an absent/ inadequate berm. Consideration was also given to determine if CXS technologies could have affected the outcome of these 21 incidents; the results are summarized in Table 2. One of the nine incidents classified as loss of control was CXS-relevant and the eight others were potentially CXS-relevant. It was determined that CXS may have relevance to the outcome for one of the two incidents involving an absent or inadequate berm and the six where operator impairment was a factor. For the three incidents caused by mechanical failure and the one incident involving both mechanical failure and an absent/inadequate berm, it was concluded that CXS would have no relevant effect. Dump-point-related incidents. Researchers identified 12 fatal accidents occurring at dump points that involved a haul truck. All 12 of the dump-point-related fatal incidents were classified as potentially CXS-relevant. Each accident resulted in one fatality — the driver of the haul truck. The dump-point accidents were divided into two subcategories: reverse-over and ground failure. In reverse-over incidents, the haul truck driver backed over the edge of the dump point, often due to the mine operator failing to ensure that proper impeding devices such as berms or bumper blocks were in place at the dump site. Of the 12 dump-point accidents, six were classified as reverse-over. The other six were due to ground failure in which the ground underneath the haul truck gave way, causing the truck to fall or overturn the edge of the dump point. Figure 4 shows the contributing factors that were identified in the 12 dump-point accidents and the number of times each factor was identified. Some incidents involved more than one contributing factor. In most of these accidents, the berm at the dump point was either inadequate or absent. There were 10 accidents with this factor. In two of the absent/inadequate berm scenarios, the drivers were using the berm as a bump stop. The constant pounding of the rear wheels of the haul truck pushed the berm back until it eventually became too close to the edge of the dump point. Undercutting of the stockpile was identified as a root cause for two of the ground-failurerelated incidents. When material is removed from the bottom of the stockpile, the ground at the dump location can become unstable. In one dump-point incident, accident investigators could not determine how the accident occurred. In this case, there were no witnesses when the accident occurred, there was no evidence of unstable ground or mechanical failure, and the berm was considered adequate. Subsequently, this accident was classified as loss of control. Of the 12 dump-point incidents, the investigations revealed that the driver was not wearing a seat belt on seven occasions (Fig. 5). In two of the incidents, the driver was wearing a seat belt. In the other three incidents, the report either did not state whether a seat belt was worn, or it could not be determined. Table 1 Summary of pedestrian/vehicle-related incidents. Other-type incidents. Eight other-type accidents involving a haul truck that resulted in nine fatalities were identified. This category was divided into the following subcategories: fire, falling material/inundation, bumping, pinning/ crushing, and slip/trip/fall. The other-type category may not be strictly limited to these subcategories. However, these were the five observed subcategories from haul-truck- related incidents that occurred from January 2005 through June 2021. Figure 6 indicates the number of occurrences for each of these subcategories. These eight accidents were considered unrelated to CXS. One accident involving a fire was caused by a ruptured hydraulic hose and subsequent fire near the engine. The haul truck was equipped with a fire suppression system, but its hoses, which were not fire-jacketed, were routed through the engine compartment and consequently damaged by the fire. In this accident, it was also found that the primary-egress hydraulically operated stairway’s hydraulic hose was likely damaged by the fire, and the alternative-egress ladder was guarded with a chain that was improperly secured using fasteners that could not be removed by hand. The falling material/inundation incident occurred at the bottom of a pit wall. The two victims and their equipment were inundated by falling material. Figure 3 Contributing factors for berm-related fatal haul-truck incidents. Three slip/trip/fall accidents occurred with the victim falling from an elevated location such as an access ladder or operator’s deck. One bumping incident occurred when a mechanic bumped his head on an unknown object while performing maintenance under a haul truck. It was assumed that the victim was not wearing a hard hat. Lastly, the two pinning/crushing incidents occurred because of inadequate blocking to prevent motion of machine components. In one case, an operator was investigating an oil leak between the operator’s cab and dump body with the dump body raised. The dump body control was left in the float position with no blocking in place. In the second incident, a mechanic was removing a strut cap. Since no blocking was in place, the truck frame dropped abruptly when the cap was loosened. Data resulting from the classification of the 54 incidents since January 2005 through June 2021 are summarized in Table 3. The table includes a comprehensive listing of subcategory results determined among the four categories involving a haul truck defined as pedestrian/vehicle-related, berm-related, dump-point- related and other-type. Discussion The primary objective of this study was to gain a perspective for developing test protocols and validation methods for CXS. The basis for the approach was to determine the most prevalent scenarios and related factors relevant to U.S. surface mining. The following sections will review the results for pedestrian-/vehicle-related, bermrelated, dump-point-related and other-type incidents. Further information will be presented as related to preventing these incidents, including consideration of the application of CXS and relevant technologies. Pedestrian/vehicle-related incidents. In total, 13 pedestrian/vehicle-related fatal incidents involving a haul truck were identified from January 2005 through June 2021. Of these, 10 were determined to be CXS-relevant and of interest to research and evaluation efforts aimed at testing and validating CXS applied within U.S. surface-mining operations. Nine of these incidents involved a forward-moving haul truck, and the other occurred during a reverse haultruck maneuver. Four of these incidents involved the haul truck initiating movement while the victim(s) were located within a 50-ft proximity. In these cases, CXS could have alerted the haultruck operator and affected persons when the pedestrian or vehicle was approaching, entering and within hazardous proximity of the haul truck. Eight of the 10 CXS-relevant cases involved the victim(s) in the forward path of a haul truck that was in motion or starting from a stopped position. The other two incidents involved, in one case, a haul truck initiating a reverse maneuver striking the cab and operator of another haul truck, and in the other case, the haul truck being hit on the side after failing to yield to moving railroad freight cars. In all 10 cases, CXS could have detected when the haul truck was approaching the asset or on course for an exclusion zone. It is important to understand that CXS may need to account for scenario-specific conditions such as the haul truck’s state of operation and ability to stop or change course. Human-related and technological factors such as detection performance are also critical to the ability of CXS to effectively prevent these incidents. In five of the eight CXS-relevant instances where the victim(s) were in the forward path, a light vehicle was crushed by the haul truck. Two of the five light-vehicle incidents involved the haul truck driving over a parked pickup truck where the light vehicle’s strobe light had been switched off. In one of these cases, inadequate illumination was a factor affecting visibility. In the other, it was determined that visibility of the victim’s pickup was momentarily obstructed by the haul truck’s cab pillar. Table 2 Summary of contributing factors for berm-related incidents. Figure 4 Contributing factors for dump-point-related incidents. These two cases exemplify that visibility is an issue concerning smaller vehicles in the vicinity of moving haul trucks and indicate that leveraging CXS to detect the presence of light vehicles within the potential forward path of a haul truck will further control efforts taken for preventing pedestrian/vehicle-related incidents. Control measures have inherent challenges and require a thorough understanding of their capabilities and limitations. For example, in many of the incidents classified as pedestrian/vehiclerelated, regulations on establishing and following rules for traffic control are cited in terms of ensuring safe operation of mobile equipment (CFR, n.d.). As an added measure of control, regulations require warnings prior to moving large equipment, inclusive of haul trucks (CFR, n.d.). These requirements are typically addressed using horns and backup alarms. The investigation reports for incidents involving a haul truck initiating a forward/reverse maneuver indicate that a warning was given by sounding the horn prior to initiating movement. Despite these warnings, it appears to be critical that the operator could not feasibly see the hazard, either directly or indirectly, due to obstructions and limited coverage afforded by installed mirrors and, in some cases, cameras. Not being able to see obstacles and assets, especially in hazardous proximity, is a recurring factor for most of these vehicle/pedestrian-related fatalities. As a best practice, flags and strobe lights are often used in conjunction to increase the visibility of smaller vehicles operated in the vicinity of haul trucks. Despite the significant benefits afforded by established rules and the use of technology, controls must be implemented with careful consideration and a comprehensive understanding of the associated impacts, benefits and limitations. For example, in one case, a flag installed on the victim’s light vehicle was barely visible from the haul-truck operator’s position while within the determined range that the accident occurred. In hindsight, this would have been improved by increasing the flag visibility and height. In another case, visibility of the victim’s light-vehicle flag to the haul-truck operator was potentially impaired by a lack of adequate illumination at the accident scene. In another example involving camera technology installed on the haul truck, it was noted that the coverage was likely inadequate to capture the victim’s light vehicle. In a separate case, the victim’s vehicle was in view of the forward camera; however it was determined as unlikely to be detected by the haul-truck operator. The researchers concluded that additional measures afforded by higher-level technology like CXS may serve to further mitigate and prevent fatal injury in cases involving pedestrians, light vehicles and related objects. In this study, incidents involving a light vehicle in the forward path of a moving haul truck account for 50 percent (5) of CXS-relevant incidents. Thereby, focusing on CXS test and validation methods specific to detecting light vehicles in the forward path of a haul truck may yield the greatest benefit. The incident data investigated in this study further suggest the significance of knowing the capabilities and limitations surrounding haul-truck and CXS performance, especially as afforded for their intended use and application. It is of equal importance and significance to address the efficacy of CXS to prevent the occurrence of false/nuisance events when a system is expected to refrain from providing an alarm or taking action (Kok et al., 2021; Ruff, 2007). To address these points, there are various standards and guidance that establish a means for testing and evaluating the performance of CXS and other technologies intended to prevent and mitigate the occurrence and consequences of potentially harmful haul-truck incidents. (Kok et al., 2021; Ruff, 2007; ISO, 2020; ISO 2021). However, additional measures are needed to validate factors relevant to detecting light vehicles, pedestrians and related objects, especially within the scope of scenarios and related factors disclosed within the fatality reports that were considered in this study. Control measures surrounding haul trucks primarily focus on improving operator awareness to overcome challenges associated with impaired and limited visibility. Typically, technology-based control measures are centered around making smaller vehicles more visible to haul-truck operators by implementing low-level technology including the use of mirrors and cameras installed on the haul truck, and flags and strobe lights on light vehicles. Collision-warning and avoidance systems (CXS) are available technology specifically intended to address pedestrian/vehicle-related collisions among surface mining haul trucks; however, implementation is sparse in the U.S. mining industry. Figure 5 Seat-belt usage for dump-point-related incidents. Figure 6 Occurrences of other-type fatal haul truck incidents. Berm-related incidents. Berm-related incidents accounted for 21 of the 54 haultruck- related fatalities identified from January 2005 through June 2021. Results indicate that CXS could have influenced the outcome of 15 incidents reviewed for this timeline. Researchers further identified possible remedies that could be combined with CXS or used as stand-alone remedies to potentially influence the outcome of these incidents, depending on the five identified contributing factors. They reviewed possible remedies for each of the factor subcategories that contributed to the berm-related incidents. NIOSH researchers first considered loss of control — the largest contributor of bermrelated incidents — as an area for technology advancement or other remedies that could help improve the outcome. CXS combined with geofencing, technology-based geographic boundaries, could help the haul-truck operators maintain control in incident scenarios related to poor road design, excessive speed and inadequate berm designs. As some of the narratives suggest, one reason operators lost control of their haul trucks, resulting in a berm collision, was inadequate stopping sight distance due to excessive road curvature. Geofencing combined with CXS could have alerted the haul-truck operator to this hazard or taken action to reduce the vehicle speed. Incident scenarios where haul-truck operators are descending grades greater than 9 percent at excessive speed place the retarder at a disadvantage (MSHA, n.d.). In these types of incidents, appropriate speed is necessary to reduce the momentum and probability of the haul truck traveling through or over a berm. CXS combined with geofencing can alert the haultruck operator of these conditions and advise the appropriate speed. In addition, other remedies such as reducing road curvature, implementing speed governors, minimizing grades and providing adequate training could have helped operators to maintain control of their haul trucks. Berm-related reports indicate that six incidents were due to impairment of the haultruck operator. In some of these incidents, a speeding haul truck overturned when it struck the berm. In others, the haul truck tipped over a berm or ran through a berm into a body of water. In these cases, CXS may have improved the outcome by alerting the impaired haul-truck operator, reducing the speed, or bringing the haul truck to a complete stop. Technological remedies could be limited in terms of influencing the outcome of some berm-related incidents, such as those involving a mechanical failure. One possible solution for this type of problem is to conduct routine preventative maintenance of braking systems before operating a haul truck. In addition, NIOSH researchers could consider berm-related incidents as a topic for further investigation beyond technology. For example, researchers could make the case for further investigation into berm design to help improve the outcome when no other options exist for stopping a haul truck. Dump-point-related incidents. CXS and other technology, as well as administrative controls, could have prevented each of the dumppoint- related fatalities identified in this review. MSHA has published a handbook that provides information related to dump-point hazards and how to recognize when dump-point conditions or practices are unsafe (MSHA, 2001). Miners and mine operators can use this handbook to ensure safe practices at their dump-point operations. The handbook describes many possible unsafe dumppoint conditions. A few of these conditions were prevalent in the analysis of dump-point-related incidents, including an inadequate or nonexistent berm, weakened edge conditions, hitting into the berm, and operating equipment while not wearing a seat belt. Regular inspections of the dump-point area can identify issues with ground stability before they can cause an accident. According to MSHA, there are four main features that suggest a dump point may not be able to support heavy equipment: Tension cracks or settlement in the area where equipment operates near the edge of the pile.A dump-point berm that is inadequate.Dumping at the edge in an area where the pile has been loaded out and made steeper than the material’s angle of repose.Movement of the slope material below the dump point. In many of the dump-point fatal accidents, an examination of the dump area could have resulted in recognizing hazardous conditions. The handbook also includes requirements for berms and restraints at dump points to serve three functions: (1) to provide a visual indicator of the location of the dump point, (2) to provide a contact point so that, if necessary, the driver knows when the berm has been reached, and (3) to impede equipment from traveling over the edge. To achieve these functions, the handbook (MSHA, 2001) requires that berms meet a minimum size, thickness and firmness. They need to be at least mid-axle height of the largest piece of equipment that will use the dump area. MSHA notes that the mid-axle criterion is only a minimum; it is good practice to make the berms as large as practical. Earthen berms need to be firm enough so that they are not easily penetrated by tires, and they must have a steep inside slope. If fine-grained material is used for the berm, then the material needs to be compacted, or the berm should be made larger. In situations where the berm is inadequate or nonexistent, the haultruck operator should dump the load short of the dump point and a dozer should carefully push the material over the edge. MSHA also encourages this practice for every dump point, regardless of berm status, for maximum safety. To avoid undercutting hazards, MSHA states that loading procedures should ensure that a truck never attempt to dump where material has been loaded out and the pile has become oversteepened. One practice that has been shown to be effective is for the loader operator to use the initial buckets of material to block the access ramp to the top of the pile while material is being loaded. When loading out is complete, the loader operator should push material from the top of the pile to reduce the slope and then construct an adequate berm before haul trucks can resume dumping at the top of the pile. Many dump-point accidents in this review could have been prevented by following the procedures and guidelines in the handbook. Even if mine workers intend to follow the proper safety protocols at dump points, there is still the possibility for accidents to occur due to inattention or unforeseen hazards. In these cases, technology can further assist in accident prevention. For reverse-over incidents, CXS can notify the driver with an alarm when he or she gets too close to the edge. For example, technology may be able to detect the point at which it is not safe to travel beyond or to detect a void or absence of ground when preparing to dump a load. A rear-view camera could also help prevent over-travel by allowing the driver to see the area behind the truck in real time while backing. Sensors and cameras can also inform drivers when they are approaching the berm, helping to avoid the unsafe dumping practice of using the berm as a bump stop. In ground-failure incidents, fatalities can be prevented with technology in addition to the previously reviewed administrative controls. It is also possible to use geotechnical instruments such as extensometers, which are used to detect landslides, to warn mine workers of ground instability. In these cases, the haul-truck operator can directly observe in passing or use a rear-view camera to detect cracks, sunken areas or other signs of unstable ground before backing. Sufficient camera resolution would be required for the operator to notice these details: for example, highresolution cameras. Other-type incidents. While the other-type incidents were not related to CXS, contributing factors were identified and recommended practices are made. Recommendations for the other-type accidents are general but should be considered to prevent similar accidents in the future. Ensuring that proper procedures are followed is critical for safety. For the other-type incidents, this includes, but is not limited to, properly installing all equipment components, conducting workplace examinations, using proper personal protective equipment (PPE) and adequately blocking the motion of machine components. For example, the fire incident may have been prevented if the fire-suppression-system hoses were not routed through the engine compartment or properly fire jacketed. It also may have been prevented if the proper, hand-removable fasteners were used to guard the alternative egress ladder. The inundation incident may have been prevented if the potentially hazardous unstable slope was recognized prior to the accident. Using the appropriate PPE during maintenance and other activities likely would have reduced the severity of the bumping incident. Likewise, ensuring that adequate blocking was in place prior to performing repairs or inspection may have prevented both pinning accidents. Remaining vigilant and exercising caution during work activities has proven to significantly improve worker safety. Similarly, maintaining awareness of one’s surroundings will decrease the likelihood of an incident. Lastly, ensuring that initial, task-specific and refresher trainings are adequate and completed by the appropriate personnel will improve the safety of all operational activities. Table 3 Summary classification data of haul-truck-related fatal accidents from January 2005 through June 2021. Conclusions From January 2005 through June 2021, berm-related incidents represented the most frequent among haul-truck-related fatal accidents in the U.S. mining industry. The application of CXS for preventing and mitigating these types of accidents has potential but is mostly uncertain, primarily due to insufficient data to support its efficacy. CXS technologies combined with geofencing could advise a haul-truck operator or assist with potentially harmful conditions that may result in a berm-related incident. For pedestrian/vehiclerelated incidents, visibility is one of the most significant contributing factors to accidents, and most of these incidents were determined to be CXS-relevant, where technology shows promise in terms of their prevention. In addition, CXS technology is applicable to preventing over-travel at dump points and may play a role in detecting conditions that indicate the potential for ground failure. The objective of this study was to gain a perspective for developing test protocols and validation methods for CXS. In conclusion, the researchers recommend focusing on detecting light vehicles in the path of a haul truck during startup maneuvers and forward travel. Following this priority is preventing over-travel while backing a haul truck at a dump point. While there are several documented incidents involving berms, especially associated with a loss of control, berm-related incidents may present significantly greater challenges in terms of determining the application-specific suitability of available technologies and their efficacy. It is important to recognize that low-level controls are the foundation and consequential requirement for successful implementation of any technologybased control, especially CXS. Limitations The findings presented in this article represent a broad overview of fatal incidents involving haul trucks at U.S. surface mines. The scope of this analysis is to ensure research and evaluation efforts are aimed at effectively addressing prevalent scenarios and relevant factors related to haul-truck accidents. The approach used for this analysis was limited to the details provided within fatal accident reports made available by the Mine Safety and Health Administration. This study is further limited by the lack of data pertaining to nonfatal injuries and near-miss incidents involving a haul truck. Individual scenarios and incidents must be thoroughly investigated to accurately determine the specific relevance of CXS and other technologies that may mitigate or prevent their occurrence. The categories and subcategories used within this analysis should not be considered all-inclusive, and the scope of analysis, along with new or additional information, may require changes. Disclaimer The findings and conclusions in this article are those of the authors and do not necessarily represent the official position of the National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention. Mention of any company or product does not constitute endorsement by NIOSH. References Mine Safety and Health Administration (MSHA). 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Aug. 26-28, 1996. https://www.cdc.gov/niosh/mining/works/coversheet1076.html Turin F.C., Wiehagen W.J., Jaspal J.S., Mayton A.G. “Haulage Truck Dump Site Safety: An Examination of Reported Injuries.” U.S. Department of Health and Human Services (DHHS), Centers for Disease Control and Prevention (CDC), National Institute for Occupational Safety and Health (NIOSH). Pittsburgh, PA. IC 9454. Mar. 2001. https://www.cdc.gov/niosh/mining/works/coversheet1018.html Kecojevic V., Radomsky M. “The Causes and Control of Loader- and Truck-Related Fatalities in Surface Mining Operations.” International Journal of Injury Control and Safety Promotion 11(4):239-251. Dec. 2004. https://www.researchgate.net/publication/7838778_The_causes_and_control_of_loader-_and_truck-related_fatalities_in_surface_mining_operations Md-Nor Z.A., Kecojevic V., Komljenovic D., Groves W. “Risk Assessment for Haul Truck-Related Fatalities in Mining.” Mining Engineering Mar. 2008. https://www.researchgate.net/publication/259739129_Risk_assessment_for_haul_truckrelated_fatalities_in_mining Bellanca J.L., Ryan M., Orr T.J., Burgess-Limerick R. “Why Do Haul Truck Fatal Accidents Keep Occurring?” Society for Mining, Metallurgy, & Exploration (SME) Annual Conference & EXPO. Preprint 20-003. Phoenix, AZ. Feb. 23-26, 2020. Bellanca J.L., Ryan M.E., Orr T.J., Burgess-Limerick R.J. “Why Do Haul Truck Fatal Accidents Keep Occurring?” Mining, Metallurgy & Exploration 38, 1019–1029 Feb. 22, 2021. https://doi.org/10.1007/s42461-021-00410-1 Earth Moving Equipment Safety Round Table (EMESRT). “PR-5A – Vehicle Interaction Systems,” Revision 2.0. Aug. 2019. http://emesrt.org/wp-content/uploads/2019/10/EMESRT-PR-5A-Vehicle-Interactions_v2_20190902.pdf Wharry, M. “Collision Avoidance Systems and Collision Warning Systems, Reducing Surface Mobile Equipment Accidents Through Technology – Mine Safety and Health Administration (MSHA) Powered Haulage Initiative.” MSHA Annual Training Resources Applied to Mining (TRAM) Conference. Oct. 9-11, 2018. https://www.msha.gov/sites/default/files/events/Collision%20Warning%20TRAM%2010_3_2018.pdf Mine Safety and Health Administration (MSHA). Fatality Reports. https://www.msha.gov/data-reports/fatality-reports/search Mine Safety and Health Administration (MSHA). Dump-Point Inspection Handbook. MSHA Handbook Series, Handbook Number PH01-I-6. Sep. 2001. https://arlweb.msha.gov/readroom/coal%20handbook/PH01-I-6%20Dump%20Point%20Inspection%20Handbook.pdf Code of Federal Regulations (CFR) Title 30 – Mineral Resources § 56.9100 Traffic control. https://ecfr.io/Title-30/Section-56.9100 Code of Federal Regulations (CFR) Title 30 – Mineral Resources § 77.1600 Loading and haulage; general. https://ecfr.io/Title-30/Section-77.1600 Code of Federal Regulations (CFR) Title 30 – Mineral Resources § 56.14132 Horns and backup alarms. https://ecfr.io/Title-30/Section-56.14132 Code of Federal Regulations (CFR) Title 30 – Mineral Resources § 56.14200 Warnings prior to starting or moving equipment. https://ecfr.io/Title-30/Section-56.14200 Code of Federal Regulations (CFR) Title 30 – Mineral Resources § 77.410 Mobile equipment; automatic warning devices. https://ecfr.io/Title-30/Section-77.410 Kok J., Grandone S., Dunn M. “PDS Validation Framework.” Australian Coal Association Research Program (ACARP) Project C26028. Jan. 19, 2021. https://acarp.com.au/abstracts.aspx?repId=C26028 Ruff, T.M. “Mining Publication: Recommendations for Evaluating & Implementing Proximity Warning Systems on Surface Mining Equipment.” U.S. Department of Health and Human Services (DHHS), Centers for Disease Control and Prevention (CDC), National Institute for Occupational Safety and Health (NIOSH). Spokane, WA. RI 9672. Jun. 2007. https://www.cdc.gov/niosh/mining/works/coversheet202.html International Organization for Standardization (ISO) “ISO 21815-1: Earth-Moving Machinery – Collision Warning and Avoidance – Part 1: General Requirements.” Draft International Standard, Geneva, Switzerland. 2020. https://www.iso.org/standard/77302.html International Organization for Standardization (ISO) “ISO 21815-2: Earth-Moving Machinery – Collision Warning and Avoidance – Part 2: On-Board J1939 Communication Interface.” Draft International Standard, Geneva, Switzerland. 2021. https://www.iso.org/standard/77303.html Mine Safety and Health Administration (MSHA). Surface Haulage Accidents… Ways to Prevent Them. https://arlweb.msha.gov/techsupp/techexchange/Haulroad/Haulroadsafety.pdf

Analysis of U.S. surface mining haul-truck-related fatalities

Authored by:
Joseph Bickson, Cory DeGennaro, Matthew Girman, John Homer

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From sessions to strategy: Revealing long-term and emerging innovation trends in data analytics, intelligent systems and automation

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