Query: line of sight lhd

title: Study of Ripple trapped Proton Behavior on LHD by 2 line of sight Measurement of Fast Neutrals

title: Virtual design modifications yield line of sight improvements for LHD operators
abstract: Several underground mining fatalities along with numerous accidents and injuries involving load haul dump machines prompted an investigation into the line of sight issues from an operator's seated position within the cabin. Human simulation software, known as Classic JACK v.3.1, was used to assess line of sight issues in a virtual environment. After initial line of sight analysis, the computer assisted design (autoCAD) drawings of the load haul dump vehicles were modified in an effort to improve line of sight. The success of the revisions was determined via a repeated line of sight analysis. Based on the line of sight findings, several operator and pedestrian strategies and consideration for mine signage were provided in order to promote safer operation of these underground mine vehicles. Relevance to industry This paper presents a novel way of evaluating underground mining equipment in a virtual environment. Manufacturers, purchasing companies, safety specialists and ergonomists have sought a visibility standard for underground mining equipment. This method may represent an approach by which line of sight from the operators' position could be evaluated for every prototype and newly manufactured vehicle.

title: Comparison of operator line of sight (LOS) assessment techniques evaluation of an underground load haul dump (LHD) mobile mining vehicle
abstract: For many years line of sight (LOS) issues for underground mobile equipment is a growing focus of research. This research is a result of the numerous fatalities and injuries which occur in the mining industry and which are related to poor operator LOS. Three assessment methods are currently used to assess operator LOS of underground mobile equipment. The light filament (LF) method is a hands on assessment method that is performed in the field. This method is not evaluated in this paper. The laser scan (LS) method of assessing equipment is a quick and reliable method that comes from the need to evaluate vehicles already located in the field. The computer simulation (CS) method can assess LOS issues using a computer aided drawing (CAD) model, which is useful for assessing current or prototype models. The purpose of the current research is to compare and validate different operator LOS assessment methods. Comparison of the results of the LS and CS visibility plots yielded similar quantifiable results. A visual comparison of the results further illustrate that the LS and CS methods are acceptable assessment tools for mobile equipment operator LOS evaluation. The visibility assessment methods are now being prepared as guidelines for the mining industry to assess current and potential designs.

title: Study of ripple trapped proton behaviour in LHD by two line of sight measurements of fast neutrals
abstract: The behaviour of helical ripple trapped particles in large helical device (LHD) have been investigated by two line of sights natural diamond detector measurements in plasma sustained with ICRF for two types of resonance configurations, i.e. on axis and saddle shaped resonances. The tail temperature increases linearly as the Stix temperature increases and then saturation follows, indicating the effect of the finite confinement time of the energetic ions. In the linear region, the tail readily increases when the line of sight is focused on the larger resonance area. The confinement time of the energetic ions is obtained from the empirical relation based on the Stix theory. The configuration with a saddle shaped resonance has a longer confinement time than the on axis resonance. Analyses of experimental measurements are consistent with the theoretical calculations including collisional ripple induced transport.

title: Evaluating Underground Mining Equipment Line of sight and Augmented Vision
abstract: Power haulage accounts for the greatest number of fatalities in Canadian, Australian, American, Indian, 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 optimized four camera placement and moderate operator head and trunk movement, a 360 view immediately around the LHD to a standing pedestrian height was realized. This case study provides further support for an augmented viewing system to improve operator LOS and illustrates the benefits of using computer based options to evaluate LOS improvements.

title: Why vehicle design matters: Exploring the link between line of sight, driving posture and risk factors for injury.
abstract: Load haul dump (LHD) vehicles have been involved in workplace accidents resulting in fatal injuries and LHD operators also report high rates of musculoskeletal injury. Poor line of sight (LOS) and awkward postures adopted by the LHD operator increase the risk of driving related accidents and musculoskeletal injury. The purpose of this case study was to simultaneously measure point of regard (POR) driving posture and sitting position during the operation of a LHD in an underground mining environment in order to further understand the link between these variables and the design of the LHD vehicle. A 5.35 m3 bucket LHD vehicle was used and several driving tasks were analysed. The case study results showed that despite the driving task, the operator looked to the left side of the vehicle 65% of the time. Postural implications include extreme neck rotation 40 degrees) for 85% of the work cycle and the average peak compression at L4/L5 was 1843N. Despite changes in driving posture the average center of pressure location for the seated operator moved very little; however changes in peak pressure were observed. The design of the LHD vehicle dictated what the operator could see, which had a direct influence on driving postures adopted by the operator and resulted in several risk factors for musculoskeletal injury.

title: Using visibility tools in Classic JACK to assess line of sight issues associated with the operation of mobile equipment
abstract: Several methods exist for measuring line of sight (LOS) associated with the operation of operator controlled mobile equipment but there is no consistent criteria used for all machine types or operating scenarios. Moreover, the standards that do exist are not particularly applicable for carrying out LOS analysis on mobile mining equipment. This paper describes a new method to evaluate LOS associated with the operation of mobile equipment, the LOS boxplot. The human simulation program, Classic JACK was used to analyse LOS from the operating position of five different load haul dump (LHD) vehicles, typically used in underground hardrock mining. The LOS boxplot method was able to demonstrate LOS associated with five LHD vehicles, and it was able to illustrate LOS improvements associated with the design modifications tested. The examples provided also show the applicability of the method for evaluating operator LOS from other types of heavy equipment.

title: Using virtual computer analysis to evaluate the potential use of a camera intervention on industrial machines with line of sight impairments
abstract: A medium sized Load Haul Dump (LHD) mining vehicle was evaluated using visibility tools in a computer simulation environment. The line of sight (LOS) available to the operator of a medium sized LHD was calculated and displayed in a boxplot. Severe LOS restrictions were observed to several areas around the vehicle. A modified LHD design, aimed at improving LOS resulted in a marginal improvement in driver LOS (20 36% Secondary viewing systems have not been widely accepted in the mining industry but several potential locations can be easily evaluated using computer simulation. This paper tested three camera locations for their ability to increase LOS to areas around the LHD vehicle that were very difficult to see from the operator's position. All camera locations were able to significantly improve LOS to 60% or greater while combinations of forward facing and rear facing cameras could improve LOS by as much as 80% Relevance to industry Several industries have successfully added closed circuit camera systems as a driving aid for vehicles with poor LOS from the operator's compartment. The mining industry has yet to adopt a widespread camera intervention on all vehicles. This paper demonstrates the potential utility of using computer simulation to evaluate camera locations on a vehicle and discusses some outstanding issues behind the ergonomics of implementing and using camera views on industrial vehicles.

title: Postural implications of obtaining line of sight for seated operators of underground mining load haul dump vehicles
abstract: Operators of load haul dump (LHD) vehicles use awkward postures that may be held statically and at extreme ranges of motion for long shift periods to spot hazards in underground mining. This study examined postural variables associated with three amounts of seat rotation intended to maximize line of sight during forward driving. Three different models, representing the 1st, 50th and 99th percentile male for height and weight, were positioned with appropriate hand and foot constraints in the virtual LHD cab modelled in Classic JACK v4.0. A total of 15 virtual movement strategies were developed to model the postural behaviour of typical workers and each virtual subject was tested, first with the seat in a neutral 0deg position and then with it rotated counter clockwise to 20deg and 45deg. Results revealed that reductions in trunk rotation, trunk lateral bend and neck rotation were associated with the seat rotation intervention. The general relationship observed was that as seat rotation increased, view of critical visual attention locations and visible line of sight area increased while postural load variables decreased. For the most part, 20deg of seat rotation was beneficial but 45deg produced significantly greater changes to postural load and visible visual attention locations.

title: Factors influencing load haul dump operator line of sight in underground mining.
abstract: The inability of load haul dump (LHD) equipment operators to see people, objects or hazards around the LHD machine they drive is a causal factor in a number of serious accidents. Line of sight evaluations were conducted on 11 different LHD models. Results indicated blind spots were caused by cab posts, and vehicles lights and light brackets. Line of sight impairments were caused by wheel well covers, buckets, fire extinguisher, light posts, radiator covers, booms, radio remote boxes, elevated engine profiles and air intake cylinders. These results were supported by questionnaires completed by 130 LHD operators. The operators indicated the bucket, lights and light brackets, boom and cab impaired line of sight. Line of sight testing and LHD operator feedback indicated line of sight to the right front corner and back right corner were typically worse than line of sight to the front left side of the vehicle. Results of this study have been used to conduct awareness campaigns within the Ontario mining industry and to suggest vehicle design modifications to LHD manufacturers.