ACARP ACARP ACARP ACARP
Open Cut

Reflective Material for Improving Night Time Driving on Haul Roads

Open Cut » Health and Safety

Published: September 97Project Number: C5041

Get ReportAuthor: Graham Lumley, K Lindus | CRA Advanced Technical Development

The objective of this project was to identify materials that could be used to enhance the night time driveability of coal mine haul roads. Materials that could be used as either a reflective coating on haul roads or roadside berms or as part of the road bed itself were examined.

 The literature review carried out by the Australian Road Research Board (ARRB) and ATD uncovered a number of articles dealing with retroreflective materials, guide posts and lane marking paint. Few relevant articles were found that related to haul road luminescence and design. These papers emphasised the need for thorough haul road design and maintenance and the influence of mobile lighting plant positions on truck productivity.

 Many haul truck drivers have concerns about the safety of driving at night time. These mostly relate to visibility of the haul road and surrounding terrain. Glare from the various artificial light sources are also a concern to some drivers.

 About 79% of accidents which occur at night are due to haul road conditions. During daylight operations a similar proportion of accidents are also related to haul road conditions (Queensland Dept. of Mines safety records). These figures are limited in scope and do not include any events where no immediate damage to persons or machines occurred. No data was found that could be used to determine the possibility (or extent) of long term damage that night time driving conditions may be having on workers (e.g. eye strain).

 Several different delineation methods were investigated, these included: glass beads; paint; roadside markers; light sensitive dyes and various white minerals. Roadside markers such as bollards, guideposts and reflective cones were thoroughly investigated. Further investigation was carried out on the two most promising surface coating options: fly-ash, a by-product of coal combustion; and light sensitive dyes.

 The production benefits to be gained from improved night time driving conditions are small. It was determined that the reduction in productivity at night is about 0.5% on main haul roads, and about 4% on in-pit temporary roads. The investigation did not assess the production losses due to equipment wear and damage. This damage could affect production in two ways: reduced operating efficiency; and increased maintenance time.

The cost of the small productivity increase gained through improved night time vision is high. Total costs for using fly-ash are anticipated to be $770 000 pa, and for light sensitive dyes to be $252 000 pa, with a $50 000 set up cost for this option. It is estimated that these road enhancements would return about $250 000 by way of improved truck productivity. Due to the unfavourable economics, it is unlikely that mines would implement either option, regardless of field trial results.

Environmental testing revealed that run-off and seepage water could potentially be contaminated by fly-ash leachate, and would need to be carefully contained. Fly-ash may create dust problems in dry conditions, adversely affecting mine operations and worker safety.

Results

This project was conducted in two stages. Stage one was planned as an evaluation of any work previously done which may assist in meeting the objective including:

>evaluating the production losses when driving at night;

>an assessment of delineation and surface treatments potentially available;

>evaluating the safety issues concerned with night time driving as opposed to daytime driving on mine haul roads.

This report outlines the outcome of stage one of the project. On the basis of stage one findings, it is recommended that the project be discontinued, with no field trials.

 Safety Issues

There are two safety issues related to night time hauling: the long term problem of driver comfort and fatigue; and the constant danger of a vehicle accident.

Experience suggests that for a variety of reasons a haul truck driver is more prone to experience discomfort and fatigue when driving at night. Due to the unnatural light conditions, such as isolated, high powered light towers and glare from oncoming trucks, drivers need to concentrate more to make out the edge of the road and irregularities in the road surface. This causes fatigue to set in more rapidly than during daylight operations. Because it is harder for the drivers to distinguish pot-holes and rises in the road surface, they inevitably have a rougher ride than drivers during day shift. Over a long period of time this can aggravate back complaints and other health problems.

The danger of a truck colliding with another vehicle or a stationary object (such as the road berm) is increased at night because it is harder for drivers to see where they are going. Locating the edge of the road and judging distances to oncoming vehicles were the principle concerns expressed by truck drivers.

Queensland's Dept of Mines attributes haul truck accidents as being due to either driver error or road conditions. A study of their safety records shows that approximately three quarters of accidents are caused by road condition, as opposed to driver error (table 1). These figures were calculated from lost time injury records for the Queensland coal mining industry since 1991.

It is likely that the lesser total number of accidents during the night is due to fewer numbers of vehicles operating during the night. Unfortunately it was not possible to collate these numbers to confirm this or to calculate the proportion of night time and day time accidents as a percentage of truck operating hours.

 The ratio between the attributable cause of the truck accidents does not vary significantly between day and night driving. At first glance this suggests that night driving is not substantially different from day time driving. However there are many other factors that are not considered such as truck speed and it would be wrong to draw these conclusions. Certainly, most truck drivers feel that driving at night is more dangerous than during the day.

 The accident figures also fail to take into account the effects of fatigue and stress that drivers experience driving at night.

 Conclusions

A suitable surface treatment for in-pit haul roads could possibly deliver the following gains:

>up to 3% cycle time reduction on in-pit haul routes;

>as yet unmeasured, decrease in equipment damage and downtime;

>a possible increase in vehicle running efficiency;

>increased driver confidence;

>possible decrease in driver fatigue and long term back problems.

Improved use of roadside markers in the form of guideposts or reflective cones will help delineate the haul road, but is not a complete solution. Markers do not help the driver's perception of the haul road surface and irregularities. They merely guide the driver along the road by making the road edge more discernible.

 The materials investigated for the purpose of treating the haul road surface are too expensive or difficult to obtain to make their use worthwhile. Further investigation showed the two most promising candidates - fly-ash and fluorescent dyes - to be uneconomical, and uncovered potential environmental problems.

Recommendations

It is recommended that the project not proceed to the field trial stage.

Roadside markers are not a complete solution, and in-pit haul routes are too transient for useful implementation. Surface treatments have been proved uneconomic and could create undesired environmental or safety problems.

Underground

Health and safety, productivity and environment initiatives.

Recently Completed Projects

C25060Development Of Borehole Shear Monitoring Device For Routine Application In Coal Mine Roadways

This project outlines the development of a cost effective, routine s...

C26063Reliable Estimation Of Horizontal Stress Magnitudes From Borehole Breakout Data

The main objective of the project is to develop a reliable and simpl...

C26053Predict Stress State And Geotechnical Conditions Near Major Geological Structures Using Microseismic Technology And Distinct Element Modelling

Stress state and geotechnical conditions often change significantly ...

Underground

Open Cut

Safety, productivity and the right to operate are priorities for open cut mine research.

Recently Completed Projects

C25031Developing Closure Criteria For River Diversions: An Alternative To Reference Sites

The use of reference sites for establishing closure criteria in area...

C25025Guidelines For Estimating Coal Measure Rock Mass Strength From Laboratory Properties - Report A Empirical Approach And Report B Synthetic Rock Mass Models

This report combined different approaches to investigate the estimat...

C27074Tyre Integrity Monitoring

Driving mine trucks with underinflated and overloaded tyres subjects...

Open Cut

Coal Preparation

Maximising throughput and yield while minimising costs and emissions.

Recently Completed Projects

C25019Adaptation Of Coal Grain Analysis To Improve Flotation Yield Estimation

This project involved sampling of full-scale flotation circuits at ...

C250083D Flotation Of Fine Particles

In this project a process for the continuous, selective agglomeratio...

C25012Dewatering Of Ultrafine Coals And Tailings By Centrifugation: Pilot Scale Studies

Dewatering of ultrafine coal and tailings is a big challenge to the ...

Coal Preparation

Technical Market Support

Market acceptance and emphasising the advantages of Australian coals.

Recently Completed Projects

C27047Combustion Characteristics Of Australian Export Thermal Coal Using Advanced Imaging Techniques

During pulverised fuel combustion, coal particles are rapidly pyroly...

C26044Physical And Chemical Interactions Occurring During Cokemaking And Their Influence On Coke Strength

This project builds onto a previous project , C24055 in which macera...

C27056Imaging Gas Penetration Inside Coals And Cokes And Determining Influence On Coke Reactivity

The suitability of cokes for use in a blast furnace is determined by...

Technical Market Support

Mine Site Greenhouse Gas Mitigation

Mitigating greenhouse gas emissions from the production of coal.

Recently Completed Projects

C27058Technological Assessment Of A Recycle Reactor For VAM Abatement

Underground coal mining emits high volumes of methane, diluted in ve...

C27008Selective Absorption Of Methane By Ionic Liquids

The connection of a ventilation air methane (VAM) abatement plant di...

C24061Proof-Of-Concept Photocatalytic Destruction Of Methane For Coal Mining Fugitive Emissions Abatement

Australia's fugitive emissions in 2015 were 41 Mt CO2-e (representin...

Mine Site Greenhouse Gas Mitigation

Low Emission Coal Use

Step-change technologies aimed at reducing greenhouse gas emissions.

Recently Completed Projects

C17060BGasification Of Australian Coals

Four Australian coals were trialled in the Siemens 5 MWth pilot scale ga...

C17060AOxyfuel Technology For Carbon Capture And Storage Critical Clean Coal Technology - Interim Support

The status of oxy-fuel technology for first-generation plant is indicate...

C18007Review Of Underground Coal Gasification

This report consists of a broad review of underground coal gasification,...

Low Emission Coal Use

Mining And The Community

The relationship between mines and the local community.

Recently Completed Projects

C16027Assessing Housing And Labour Market Impacts Of Mining Developments In Bowen Basin Communities

The focus of this ACARP-funded project has been to identify a number...

C22029Understanding And Managing Cumulative Impacts Of Coal Mining And Other Land Uses In Regions With Diversified Economies

The coal industry operates in the context of competing land-uses that sh...

C23016Approval And Planning Assessment Of Black Coal Mines In NSW And Qld: A Review Of Economic Assessment Techniques

This reports on issues surrounding economic assessment and analysis ...

Mining And The Community

NERDDC

National Energy Research,Development & Demonstration Council (NERDDC) reports - pre 1992.

Recently Completed Projects

1609-C1609Self Heating of Spoil Piles from Open Cut Coal Mines

Self Heating of Spoil Piles from Open Cut Coal Mines

1301-C1301Stress Control Methods for Optimised Development...

Stress Control Methods for Optimised Development and Extraction Operations

0033-C1356Commissioned Report: Australian Thermal Coals...

Commissioned Report: Australian Thermal Coals - An Industry Handbook

NERDDC