ACARP ACARP ACARP ACARP
Open Cut

Optimisation of Structural Performance of Trucks

Open Cut » Maintenance & Equipment

Published: March 06Project Number: C13043

Get ReportAuthor: Gerard Chitty, Priyath Amaratunga, Alan Hon, Brian Kerezsi, Daya Dayawansa, Hui Jiao, Henry Bartosiewicz, Osvaldo Cortes, Tom Rucinski | MTI, Monash University

The majority of truck and shovel operations in the Australian coal industry use Caterpillar 789, 793 or Komatsu 830, 930 trucks. These trucks are at various stages of their service life and many of them have experienced fatigue cracking at several locations after a relatively short duration of time in service (in some instances as low as 15,000 hrs). The life of a truck is generally limited by the life of its chassis.

The key objective of ACARP project C13043 was to optimise the structural performance of mining trucks in the Australian Coal industry. Industry monitors nominated the Caterpillar 793 truck type for the study. The main objectives of this research project were:

  • Develop a thorough understanding of the structural performance of critical areas of the truck during normal mining operations and estimate service life.
  • Outline the influence of mine operating conditions such as haul road conditions on the service life of the chassis.
  • Recommend best practice procedures for the normal mining operations, including haul road condition, to maximise the life of the chassis.
  • Recommend a cost effective repair procedure for 2-3 critical components on the chassis.
  • Recommend an overall repair strategy to maximise the life of the chassis.
  • Produce guidelines that can be used for preparation of risk management strategies for optimising the structural performance of the truck.

The study included a comprehensive instrumentation and test program of the RD1 – CAT 793C truck at Saraji mine, detailed FE analysis of the truck chassis, review and analysis of past failures of several CAT 793 trucks at BMA mines and a detailed fatigue assessment. The Saraji mine site provided a CAT793 truck for the instrumentation and test program.

Following the review and analysis of the history of failures, the industry monitors nominated the torque tube to main rail connection and the front strut beam connection areas for developing a modified repair procedure to improve the repair life at these locations, as their repair life was lower than 2,000 hours.

The following conclusions can be made from the study:

  • Cracking was observed in several areas of the CAT 793 truck chassis (torque tube to main rail connections - top and bottom, front strut beam connection, vertical welding in main rail etc.) after 12,000 hours of service. Significant cracking in several areas was observed after approximately 25,000 hours of service.
  • The service life of components after repairs was extremely low in most areas. At the torque tube to main rail area the service life after repairs was around 600 – 900 hours. In most areas, the service life after repairs was greater than 2,500 hours.
  • Extremely high peak stresses, stress ranges and a significant number of stress cycles were observed in several locations of the truck chassis during normal operations. Stress ranges of up to 650MPa and peak tensile stresses of up to 434MPa were recorded during the test period which would be above the yield stress of the material. The highest stresses were observed due to racking/twisting, pitching/bouncing and rolling when driving out of the pit and dump area, and during dumping.
  • The payload distribution during the test period was within the rated capacity of the truck.
  • The stresses obtained from the FE analysis for the critical load cases were similar to those observed during the measurement.
  • Fatigue assessments conducted based on BS7608 [1] for several critical locations provided results similar to the service hours to when the first crack was observed.
  • The fracture mechanics approach for fatigue life estimation [2] clearly showed that initial flaw size has a major influence on the component life.
  • For the torque tube to main rail connection, the Caterpillar repair manual [6] does not refer to a specification for the repair welds and no repair weld qualifying criteria is specified. This is the most highly stressed/critical area of the chassis and the repair welds should conform to a stringent welding standard.
  • For all other areas, the manual specifies that weld repairs should conform to the AWS D14.3 [5] standard.
  • Several repairs observed during the inspection of the trucks clearly showed poor weld repair quality which do not comply to the AWS D14.3 [5] standard.
  • In order to improve the fatigue performance of the CAT 793 truck chassis the following should be addressed:
    • The peak stresses, stress ranges and number of stress cycles experienced by the truck during operations should be reduced.
    • Critical areas where repeat cracking has been observed should be modified/redesigned to reduce stresses to acceptable levels.
    • Weld quality during repairs should be maintained to a very high standard as the initial flaw size has a major impact.

It is recommended that the following studies be performed to improve the structural performance of the CAT 793 trucks:

  • Assess the impact of stress relieving on the torque tube area following weld repairs.
  • Re-design specific areas such as the torque tube to main rail connection to reduce stresses to an acceptable level.

Underground

Health and safety, productivity and environment initiatives.

Recently Completed Projects

C26059Proof Of Concept Of The Electronic Spark Test Apparatus On Existing Known Power Supplies

This project continued a long running research program into an elect...

C26070Industrialisation Of Proof Of Concept Wall-Flow DOC + Filter System

The need to protect workers from diesel particulate matter (DPM) had...

C25001Ventilation And Gas Management - Underground Coal Mines

This planning guideline has been prepared to assist mine operators t...

Underground

Open Cut

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

Recently Completed Projects

C26034Coking Properties Deterioration In Small Samples

Accurate evaluation of coking coal parameters at the exploration sta...

C23029Alternative And Sustainable Explosive Formulations To Eliminate Nitrogen Oxide Emissions

This technical report describes the technology of a novel mining exp...

C25005Site Based Trials Of Alternative Explosive Formulations To Eliminate Nitrogen Oxide Emissions

This report documents the outcomes of Phase 3 of this project and b...

Open Cut

Coal Preparation

Maximising throughput and yield while minimising costs and emissions.

Recently Completed Projects

C26009Improved Precision Of Determining Coal In Urban Dust

Dust samples collected in coastal locations using High Volume Air Sa...

C26015Novel Characterisation Of Coal Petrography For Improving The Dewatering Of Fine Coals Using Chemicals

This project aimed to develop alternatives to existing mechanical de...

C26014Low Cost Online Measurement Of Particle Size And Density For Diagnostics Across The Fine Coal Circuit

This project has developed a novel prototype optical system for prof...

Coal Preparation

Technical Market Support

Market acceptance and emphasising the advantages of Australian coals.

Recently Completed Projects

C26045Mineralogy Effects On The 3D Porosity Evolution Of Coke And Coke Reactivity

CRI/CSR CO2 combustion data are key metrics of coke quality and perf...

C25049Fusibility Of Coal Blends And Minerals In Coking

The CSIRO optical reflected light imaging CGA (Coal Grain Analysis) ...

C25045Stage Two - Assessment Of In Situ High-Temperature Strength Of Cokes

Stage I of this project established a reliable and repeatable proces...

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