Evaluating Underground Mining Equipment Line-of … · 2012-06-22 · Evaluating Underground Mining...

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EMESRT Design Evaluation Case Study 12-02 Evaluating Underground Mining Equipment Line-of-sight and Augmented Vision Alison Godwin and Tammy Eger School of Human Kinetics, Laurentian University, Sudbury, ON, CANADA Abstract Power haulage accounts for the greatest number of fatalities in Canadian, Australian, American, In- dian, and Spanish mines, and is the fourth leading cause of fatal accidents in underground African mines. However, this rate is expected to grow with a move toward increased power haulage and less manual labour in Africa. Many of the fatal injuries have been associated with load-haul-dump (LHD) operation due to their notoriously poor line-of-sight (LOS) hampered by a sideways-seated operating position. To date, modifications to cabs, engine profiles, buckets, lights and, installation of rotated seats, have led to only moderate LOS gains. This case study reviews several approaches for LOS evaluation including computer simulation methods like the LOS boxplot. The benefits of a secondary viewing device to augment operator visibility are presented. A four-camera system was evaluated in a field trial. Placement of cameras to maximize LOS was determined on-site using field methods, and enhanced with immediate feedback provided by a custom written computer-based LOS assessment program. Prior to camera installation a 1.7m tall pedestrian was first visible to the LHD operator ~5m in front of the bucket, ~6m behind the engine and over 12m from the front right corner. With the op- timized four camera placement and moderate operator head and trunk movement, a 360-view imme- diately around the LHD to a standing pedestrian height was realized. This case study provides fur- ther support for an augmented viewing system to improve operator LOS and illustrates the benefits of using computer-based options to evaluate LOS improvements. Background Over the last three decades mining methods have moved towards mechanization and automation. While this has generally reduced the number of seri- ous injuries to miners, it has also increased the num- ber of fatalities that result from the interaction of large pieces of machinery in small, confined road- ways (Groves 2007; Kunar et al. 2010). Not only have the numbers of underground mining machinery in- creased, but there has been a concomitant increase in the size of the machines and payloads, in an effort to increase productivity. The machinery has also evolved to include full cabins rather than simple roll- over protection systems (ROPS), and while these cabs provide full environmental protection, they also drastically limit the line-of-sight (LOS) from the op- erating compartment (Figure 1.1). The inability of the mobile equipment operator to clearly see pedestri- ans, objects, or hazards around the machine has con- tributed to a number of accidents resulting in equipment damage, lost work time, and fatal injury (MASHA 2006; NIOSH, 2001). Canadian data published in 2001, by the Mines and Aggregates Safety and Health Association (MASHA) summarized accident statistics for LHD vehicles in the Ontario mining industry over a 15-year period between 1985 and 2000. During this period, 1690 ac- cidents involving LHD vehicles were reported and poor LOS was identified as a causal factor in 24% of these accidents. Hitting pedestrians, mine walls and other vehicles accounted for 16% of all accidents while unseen ground hazards (potholes, muck on the ground or falling into holes) accounted for a further 8% of these accidents (MASHA, 2001). Powered haulage continues to have the 3rd highest injury/ fatality rate for the time period of 2005-2009 in On- tario, Canada (WSN, 2011). Coroner’s inquests in Ontario, Canada continue to provide evidence that the LOS problem for seated drivers of mobile mining equipment has not been adequately addressed (OMSG 2009). 2012 - Earth Moving Equipment Safety Round Table - emesrt.com

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EMESRT Design Evaluation Case Study 12-02

Evaluating Underground Mining Equipment Line-of-sight and Augmented Vision

Alison Godwin and Tammy Eger School of Human Kinetics, Laurentian University, Sudbury, ON, CANADA

Abstract

Power haulage accounts for the greatest number of fatalities in Canadian, Australian, American, In-dian, and Spanish mines, and is the fourth leading cause of fatal accidents in underground African mines. However, this rate is expected to grow with a move toward increased power haulage and less manual labour in Africa. Many of the fatal injuries have been associated with load-haul-dump (LHD) operation due to their notoriously poor line-of-sight (LOS) hampered by a sideways-seated operating position. To date, modifications to cabs, engine profiles, buckets, lights and, installation of rotated seats, have led to only moderate LOS gains. This case study reviews several approaches for LOS evaluation including computer simulation methods like the LOS boxplot. The benefits of a secondary viewing device to augment operator visibility are presented. A four-camera system was evaluated in a field trial. Placement of cameras to maximize LOS was determined on-site using field methods, and enhanced with immediate feedback provided by a custom written computer-based LOS assessment program. Prior to camera installation a 1.7m tall pedestrian was first visible to the LHD operator ~5m in front of the bucket, ~6m behind the engine and over 12m from the front right corner. With the op-timized four camera placement and moderate operator head and trunk movement, a 360-view imme-diately around the LHD to a standing pedestrian height was realized. This case study provides fur-ther support for an augmented viewing system to improve operator LOS and illustrates the benefits of using computer-based options to evaluate LOS improvements.

Background

Over the last three decades mining methods have moved towards mechanization and automation. While this has generally reduced the number of seri-ous injuries to miners, it has also increased the num-ber of fatalities that result from the interaction of large pieces of machinery in small, confined road-ways (Groves 2007; Kunar et al. 2010). Not only have the numbers of underground mining machinery in-creased, but there has been a concomitant increase in the size of the machines and payloads, in an effort to increase productivity. The machinery has also evolved to include full cabins rather than simple roll-over protection systems (ROPS), and while these cabs provide full environmental protection, they also drastically limit the line-of-sight (LOS) from the op-erating compartment (Figure 1.1). The inability of the mobile equipment operator to clearly see pedestri-ans, objects, or hazards around the machine has con-tributed to a number of accidents resulting in equipment damage, lost work time, and fatal injury

(MASHA 2006; NIOSH, 2001).

Canadian data published in 2001, by the Mines and Aggregates Safety and Health Association (MASHA) summarized accident statistics for LHD vehicles in the Ontario mining industry over a 15-year period between 1985 and 2000. During this period, 1690 ac-cidents involving LHD vehicles were reported and poor LOS was identified as a causal factor in 24% of these accidents. Hitting pedestrians, mine walls and other vehicles accounted for 16% of all accidents while unseen ground hazards (potholes, muck on the ground or falling into holes) accounted for a further 8% of these accidents (MASHA, 2001). Powered haulage continues to have the 3rd highest injury/fatality rate for the time period of 2005-2009 in On-tario, Canada (WSN, 2011). Coroner’s inquests in Ontario, Canada continue to provide evidence that the LOS problem for seated drivers of mobile mining equipment has not been adequately addressed (OMSG 2009).

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Figure'1:'Example'LOS'from'the'LHD'operator'’s'position.'The'LHD'vehicle'operator'is'unable'to'see'a'5’6”'pedestrian'twenty'feet'away'from'the'cab.'Also,'the'mine'floor'only'becomes'visible'90'feet'away'from'LHD'vehicle'operator.''''Figure  1:  Example  LOS  from  the  LHD  operator  ’s  posi;on.  The  LHD  vehicle  operator  is  unable  to  see  a  5’6”  pedestrian  twenty  feet  away  from  the  cab.  Also,  the  mine  floor  only  becomes  visi-­‐

ble  90  feet  away  from  LHD  vehicle  operator.      

A recent review of MSHA records suggests that the general category of equipment represents the highest number of fatalities between 1995 and 2004, and fur-ther, that fatal injury to miners was four times higher than the average rate for other industry (Groves, 2007). Powered haulage represented 8% of the more than 190 000 accidents but along with the machinery category accounted for 51% of fatal incidents (Groves, 2007). This was higher than the reported values from the 1986-1995 NIOSH data (NIOSH, 2000), and suggests that more work must be done to improve operating conditions for mobile equipment operators. The two most frequently used machines in underground mining, the haul truck and LHD, ac-counted for 16% and 9% of fatalities (Groves 2007). Burgess-Limerick (2011) makes a case for the impor-tance of removing pedestrians from the areas where continuous miners and other large mining equip-ment is operating by identifying that being struck by, or caught between these machines represent frequent accident causes in Australian mining.

Internationally, a review by Michelo et al. (2009) found injury rates in Zambia mines to be lower than other African countries but higher than most high-income countries (USA, Australia, Canada, South Africa). The category of powered machinery ranked fourth for injury occurring in underground mines and accounted for 12% of overall injuries (and no fatalities) but the lower rate of mechanization may be keeping these numbers lower for the moment (Mi-chelo et al. 2009). Indian coal mines ranked machines (including LHDs) as the leading cause of fatalities at 19.5% (as cited by Kunar et al. 2010). In Spanish mines, 13.7% of serious or fatal accidents were caused by being run over or hit by machines (San-miquel et al. 2010) Mobile machinery for under-ground use are designed with careful consideration to the physical constraints of the mining environ-ment, which include low vertical and horizontal clearances, and the machinery is rarely designed to maximize driver sight lines.

The bulk of injuries in underground mining occur on the ubiquitous Load-Haul-Dump (LHD) machine

(Burgess-Limerick et al. 2011), a machine that re-quires the operator to maintain a sideways-seated position, which further restricts their ability to see people, objects or hazards around the machine (Jeffk-ins et al., 2004). In response to the reported fatalities among operators of underground mobile machinery, past research has focused on identifying machine components and driving scenarios that lead to de-creased LOS on LHDs (Boocock et al., 1996; Boocock and Weyman, 1994; Eger et al., 2004; Godwin et al., 2008). Marx (1987) found that the following vari-ables influenced viewing conditions: vehicle outline and orientation of outer corners, obstructions caused by air filters, tanks and other add-ons, proper light-ing of working conditions and canopy/cabin sup-port structures. Rushworth (1996) listed canopy supports, fixed seat positions, headlights, mud-guards and hydraulic control units as being respon-sible for restricted forward sight lines.

Eger et al. (2004) reported that complete blind spots were linked to cab posts, the back of the operator cab, lights and light brackets. An operator question-naire further identified wheel well covers, bucket lip shape or oversized bucket, light posts, radiator cover, booms and hoses, engine style, air intake cylinders and add-on features such as fire extinguishers and radio remote boxes to be related to restricted LOS (Eger et al, 2004). Once the design of the machine was identified as less than optimal for safe and effi-cient operation, several investigations attempted to identify the components most likely to produce a substantial improvement to LOS. Although some innovative ideas have been presented, more than one research group has suggested that a complete redes-ign of the mining machine concept would be re-quired to substantially improve LOS (Godwin et al. 2007; Schutte and Shaba, 2003).

The information available for other types of under-ground machinery is not as extensive, but haul trucks in general (underground, surface, open-pit) have been recognized to be the single-most hazard-ous piece of mobile mining equipment, causing 22.36% of mining equipment fatalities in the United States (Kecojevic, 2007). It is known that under-ground haulage trucks contribute to those overall numbers of mine fatalities (Kecojevic et al., 2007; MSHA, 2009).

Poor operator LOS resulting from machine design appears to be a contributing factor in a significant number of equipment-related fatalities. For this rea-son, measuring and evaluating LOS continues to play an important role in understanding how indus-try can reduce the incidence of accidents involving

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mobile equipment. This case study describes several computer-based options for measuring operator LOS, and introduces the evaluation of a secondary viewing aid using these methods.

Evaluting Line-of-Sight

Several standards have been developed to evaluate earth-moving machinery, including the International Organization for Standardization (ISO) 5006-1, which evaluates masking widths on a 12m radius circle at ground level as well as a rectangular perimeter lo-cated 1m away from the machine at a height of 1.5m. The machine is considered to have acceptable or un-acceptable visibility based on the number and width of the masking shadows. The Society for Automo-tive Engineers (SAE) has created a variation to the ISO 5006-1 standard, labeled XJ1091. The Forest En-gineering Research Institute of Canada (FERIC) de-veloped a similar method to the ISO 5006-1 Standard to measure visible and non-visible areas around a 12 meter radius using a mirror mounted on a 45 degree angle measuring stick (Golsse, 1994).

Research by Eger et al (2004) used a hybrid of the FERIC and ISO standards to document LOS around a customized rectangular perimeter using a light fila-ment in the operator’s seat to represent the eye posi-tion of a 170-centimeter, 65-kilogram person and a mirror-mounted measuring device. Based on results obtained around the rectangular perimeter, research-ers extrapolated a line of sight to ground, 1 meter and 1.7 meters above ground in order to create line-of-sight diagrams (Eger et al. 2004). In this manner, both visibility impairments and complete blind spots were plotted around the vehicle (Figure 2).

A variation on LOS evaluation was developed for shuttle cars and involves representing the visual re-quirements for operators using Visual Attention Lo-cators (VALs). These positions were specified from known fore-aft, side-side lateral and up-down height reference locations on the machine (Sanders and Kel-ley, 1981), and divided into priority one VALs (n=70) that included points that had to be observed by the operator to provide information on the position of the machine in the roadway, location of obstacles and hazards and position of vehicle relative to roof bolts during tramming, loading and dumping. Additional priority two, three and four points (n=24) related to less critical aspects of operating shuttle cars and could be associated with some degree of neck or trunk deviation. Human factors research completed on underground mobile mining equipment by the Pittsburgh Research Laboratory used 54 specific VALs identified for shuttle cars that represented 95%

of all visual features necessary for operation (Sanders and Kelley, 1981).

Figure'2'LOS'plot'represents'obstructed'line'of'sight'to'ground'level'for'a'seated'operator.'The'black'rays'represent'complete'blind'spots'resulting'from'cap'and'light'post'design.'Scale'in'meters.

Figure 2 LOS plot represents obstructed line of sight to ground level for a seated operator. The black rays repre-sent complete blind spots resulting from cap and light post design. Scale in meters.

A discussion on the limiting aspects of these various methods is warranted. It is largely inappropriate to use the ISO or SAE standards for evaluation of un-derground mobile equipment because the acceptable width of maskings has not been specifically defined for underground mining machinery (ie. LHDs, haul trucks). The greatest limitation of the other field line-of-sight methods was the time required to produce one analysis. The adapted FERIC method required three hours of onsite measuring time, in addition to lab calculation time to produce the plots for each ve-hicle (Eger et al, 1999).

The results did not specifically identify what pieces of the machine were causing the restriction, and did not facilitate design recommendations. Limitations exist for the use of VALs to determine operator visi-bility. The VAL system also lacked robustness since it was difficult to identify or judge which locations were crucial for operation, and even more question-able to evaluate a machine based on the ability or inability to see a few locations. There are certain VAL’s that will be impossible to see under the best underground circumstances and a machine may re-ceive an undeserved poor assessment.

For this reason our research team sought a way to predict and accurately model the LOS available to an operator and a reproducible, efficient method to test modifications or design prototypes. Based on this, a computer simulation method was developed in a specialized program, and subsequently validated

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against a laser scanner method (Bhatthacherya et al. 2006) with results shown in Figure 3.

Figure 3 The LOS Boxplot to the left was generated using the laser scan (LS) method to evaluate operator sight lines. The blue areas represent sight lines that are visible to the LHD vehicle operator. The checkered areas represent space where sight lines are not visible. The LOS Boxplot to the right was created using the Computer Simulation (CS) method. The green areas represent sight lines that are visible to the LHD vehicle operator. The red areas repre-sent space where the operator has no visibility.

Our research group chose the software known as Classic JACK as the optimal tool for conducting LOS computer analysis, because of its ability to position human avatars in the seated driving position of a machine, in addition to several eye view and visibil-ity functions that were built in to the available Task Analysis Toolkit (TAT). Specifically, the coverage plane tool in Classic JACK was used to generate red and green plots as observed in Figure 3. Coverage planes are flat surfaces that can be scaled to any size and oriented in any direction in the environment. The basis of the visibility analysis is that a line is placed at the eye point of the virtual operator and extended to each nodal point on the coverage planes. The number of nodal points can be specified by the user for more or less resolution where a very high resolution results in a solid appearance. When the hypothetical line between the eyepoint and a nodal point does not intersect any part of the vehicle, a clear LOS exists and the nodal point is represented in green. If the line intersects the vehicle before it reaches the intended nodal point, there is no LOS exists and the nodal point is represented in red.

Based on industry feedback, the initial approach for computer LOS analysis was done on a series of con-nected coverage planes that created a boxplot shape of customizable size (Eger et al. 2010). The boxplot approach was then expanded to a more standardized computer line of sight evaluation (CLOSE) depicted in Figure 4, which includes relevant planes situated at positions like the necessary stopping distance (West et al. 2005). Percentage of available LOS for each coverage plane is also provided by the program as a quantitative assessment. The various boxplots methods have been used to evaluate potential design

modifications (Godwin et al. 2008), prototype de-signs (Henry and Godwin, 2010), and most recently, camera systems for navigation purposes (Godwin 2012).

Figure 4: Computer Line of Sight Evaluation (CLOSE) de-picts restricted LOS (red) and available LOS (green) on a 1 meter perimeter around the machine, as well as at impor-tant stopping distances ahead and behind the operator.

Strategies to improve line-of-sight

Current mobile mining equipment designs have been associated with impaired lines-of-sight, cramped operator’s compartment, and inadequate seat adjustability (Eger et al., 2004; Godwin et al., 2007; Kittusamy and Buchholz, 2004), all of which contribute to the asymmetric seating postures adopted by LHD vehicle operators. This statement is echoed by McPhee (2004) who concluded in her re-view of the state of ergonomics in mining by saying: “the link between prolonged sitting, poor cab design, and vibration, with back and neck pain is being rec-ognized but has yet to be addressed in any system-atic way by the mining industry”. As reviewed ear-lier, several researchers have studied the components of the machines that result in impaired LOS. Addi-tional work has been done to identify interventions that minimize awkward working postures, as well as maximize LOS.

The benefits of installing a rotating seat were demon-strated as early as 1978 by Bottoms and Barber who reported an 11º decrease in trunk rotation and a 16º decrease in neck rotation, when a 20º swivel seat was installed in a tractor. In 2001, Toren and Oberg con-firmed the benefits of a rotating tractor seat by show-ing a 50 % reduction in extreme trunk twisting dur-ing plowing tasks. Rotating seats have also been installed in fork-lifts resulting in more neutral driv-ing postures and reduced postural loading (Taoda et al., 2002). Similarly, operators of forestry and crane machines with rotating compartments had signifi-cantly lower mean head rotation angles (7º and 14º

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respectively) than when working without rotating operator compartments (22º and 34º respectively) (Eklund et al., 1994).

Based on this past research, Godwin et al. (2007) demonstrated that a 45º seat rotation resulted in a significant reduction in LHD operator neck rotation, trunk rotation, and trunk lateral bend while simulta-neously improved line-of-sight to areas in the work environment that were critical for safe operation. Hence, there is an opportunity for mining equipment manufacturers and the mining industry to evaluate the traditional design of LHD vehicles, in order to enable the LHD operator to utilize more neutral working postures. This approach will be even more important with the introduction of Tier IV engines being introduced to meet diesel-emission standards, the anticipated effect being another increase in the size of underground machinery.

Secondary viewing devices implemented elsewhere in industries have not only improved visibility out-comes, but also improved operator posture. Tobisch et al. (2005) reported that using a GPS navigation system with a computer screen during mulching tasks in the forestry industry could reduce operator head rotations by 90%. A rear-view mirror to aid in detecting hazards was able to reduce the number of right and left glances used by a forestry logger (Cloutier, 2002). A virtual study by Godwin and Eger (2009) showed the benefits of adding cameras to LHD vehicles, in order to allow operators to main-tain a neutral sitting posture and still see areas of the working environment that were previously not visi-ble when in a neutral sitting posture.

Secondary viewing devices have been recommended to aid operators in spotting dangers around their machine, such as ground hazards, and pedestrians and to improve opposite-side vision, especially when driving into corners (Schutte and Shaba, 2003). In an effort to improve operator LOS, several new tech-nologies have been tested in both surface and under-ground mining applications.

Ruff (2001) tested a variety of technologies (closed-circuit video cameras, radar or radio-frequency iden-tification (RFID), ultrasonic, infrared or thermal cameras, GPS) on surface haulage trucks and used reliable detection zone, risk of false alarms, coverage area and adjustability, and weather proofing as measures of usefulness for the application. Although they do not come to a consensus on the best available technology, they do document the pros and cons of a variety of systems. The GPS system is not feasible for underground use, and the RFID approach has not

been widely accepted due to the need to have all possible objects tagged. Closed circuit television sys-tems (CCTV), including variations with infrared, and thermal imaging options are making their way into mainstream automobile driving, and may represent a realistic approach to solving the LOS restrictions on large, underground machinery.

Case study - Augmented vision

This paper will demonstrate the impact that the four-camera PROVIX system has on LOS for a seated op-erator of a mid-sized, enclosed-cab LHD. The exist-ing LOS for the operator of a machine with a 4.8m3 bucket capacity was depicted in Figure 2. The solid rays extending from the seated position reflect sev-eral blind spots caused by the design of the cab posts, and the light brackets situated on the front booms. The research team uses a customized pro-gram to plot the available LOS observed in Figure 2 on a field-based laptop so that immediate feedback is available to the camera installer. For comparison, based on field work with an average-sized male op-erator in the machine seat, a plot can be produced that represents the LOS when moderate amounts of head, neck and trunk movement are used to view the area around the LHD (Figure 5). Although the dis-tance to ground is not altered, several complete blind spots resulting from the cabin posts can be removed from the plot.

The corresponding plot that depicts LOS to a stand-ing pedestrian is also plotted in Figure 6 with a much smaller scale used. The ability to see a standing pe-destrian (1.7m tall) is reasonable for this machine: LOS to the front (~5m) and rear (~6m) while the lights produce obstruction to ~12m mark to the right front area, and the air cylinder on the rear obstructs LOS to ~6m to back right corner. Based on the 2D plots generated, the key areas around the machine that were targeted for improved LOS via the four-camera (PROVIX) system were identified. Since the plots were produced while onsite, the research team could consult with the installer to optimize place-ment and angles used, as well as an experienced un-derground hardrock miner, who could provide feed-back on appropriateness of the chosen locations.

The four camera locations included: Front Camera located under the Cab roof structure pointing for-ward, Front Right Camera located on the back half of the machine angled outwards to the front right, Rear Camera positioned in the grill on the rear of the ma-chine, and a Back Right Camera located under the step on the front half of the machine pointing to the back right corner of the machine (Figure 7).

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Figure 5: LOS plot represents obstructed line of sight to ground level for a seated operator using moderate amounts of head, neck and trunk flexion. Relying on some operator movement reduces the number of blind spots resulting from the cab posts. Scale in meters.

Figure 6: The green area represents the obstructed LOS to a standing pedestrian (1.7m) tall from the operator’s seated position when using moderate amounts of head, neck and trunk movement . Scale in meters.

The cameras were temporarily mounted in these lo-cations, allowing the research team to perform a sec-ond assessment on the rectangular perimeter, from the perspective of each camera. The LOS results us-ing the PROVIX Camera System in conjunction with best operator LOS for the rectangular perimeter are plotted in Figure 8. When comparing to the plot in Figure 5, it is evident that the PROVIX Camera Sys-tem eliminates all blind spots with the exception of the area directly behind the operator. The projected LOS to ground level has been nearly eliminated, with the exception of three areas: directly in front of the machine is still obstructed since the Front Cam-era attached to the cab cannot provide complete LOS over the bucket and front half of the machine; the

area to the back right because the Back Right Camera was positioned under the step for protective pur-poses but the step is recessed from the body of the machine; and the area directly across from the opera-tor on the right side, which can be eliminated with optimal angling of the Front Right Camera.

Figure'7Camera locations depicted in red blocks for the PROVIX quad-camera system. Top: Back Right Camera. Middle: Front Right Camera on body and Front Camera under Cab

Figure 7: Camera locations depicted in red blocks for the PROVIX quad-camera system. Top: Back Right Camera. Middle: Front Right Camera on body and Front Camera under Cab Canopy. Bottom: Rear Camera on back of ma-chine.

A more realistic scenario was also evaluated for LOS, in which the bucket was rolled back into the empty tramming position. The results are depicted in Fig-ure 9. The Front Camera and Front Right Camera reduced the obstructed area to ground level directly in front of the machine, although substantial block-ages still exist out as far as 35-45m in front of the LHD. However, when evaluating obstruction to a standing pedestrian (1.7m), Figure 10 demonstrates (on the same scale used in Figure 9) that the PROVIX Camera System in combination with moderate head, neck and trunk movement essentially provides a 360! view around the machine to a standing pedestrian height.

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Figure 8: The obstructed LOS to ground when using the PROVIX Camera System in conjunction with operator head, neck, trunk movement. Scale in meters.

Figure 9: LOS to ground using the PROVIX camera system when bucket is in raised position

Summary

Over the last three decades mining methods have moved towards mechanization and automation, which has increased mobile equipment operation underground. With more mobile equipment under-ground, LOS from the operating compartment has turned into a legitimate safety concern. It will con-tinue to be a concern as manufacturers increase the size of the machines operating in small, narrow pas-sages. The inability of the mobile equipment opera-tor to clearly see pedestrians, objects, or hazards around the machine has contributed to a number of accidents resulting in equipment damage, lost work time, and fatal injury. In an effort to prevent future accidents related to poor LOS, researchers have util-ized a number of methods to evaluate operator LOS during mobile equipment operation. The computer simulation methods presented in this case study

provide a compelling way to analyze LOS on exist-ing or prototype machines. Until a convincing redes-ign addresses the severe LOS issues that exist, a rea-sonable way to improve the operator’s view around the LHD may be through the use of camera systems, as demonstrated in this paper.

Figure 10:LOS to a standing pedestrian (1.7m tall) using the PROVIX camera system when bucket is in raised posi-tion on same scale as Figure 9 for comparison

Acknowledgements

The LOS research team of the Center for Research in Occupational Safety and Health wishes to thank the mining industry for their ongoing interest and sup-port, and Winsted Group Inc. for their partnership with respect to testing the PROVIX camera system.

References

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