Strip dozing is used in particular coal mines around the world where the coal is in close proximity to the surface. The process involves sequencing dozers in close proximity to each other to push over-burden material for distances often involving hundreds of metres. The push sequence is repeated until the coal seam is exposed. The overburden at at the Wilpinjong site in the Hunter Valleys, consists of a complex mixture of incompetent blocky shale and clay particulates.

In this application we have applied high performance computational discrete element techniques to simulate the dozing of blocky-shale material at full industrial scale. The shale material was simulated in 2D with a random ensemble of polyhedra discrete elements and disk elements. Draft force predictions were then used to calibrate full 3D dozing models, populated with mixtures of tuned spherical elements.

Project outputs

• A numerical method for modelling blocky materials on an industrial scale (2D
• plane strain through to full 3D).
• A numerical tool in the form of full-scale 3D models that predict dozing draft forces
• and power for blocky materials under steady-state dozing conditions.
• A deeper understanding of particle angularity showing that angularity has a marked effect on peak draft loads. This means that 3D spherical elements can be used for steady-state predictions but not the peak draft loads associated with the initial push and dislodgement of blocky material.
• The results have been diffused to the industry participants.
• One of the major outputs of this project is that the industry participants have
• submitted an industrial proposal through ACARP to apply numerical methods for dozer blade efficiency studies. The proposal aims to maximize dozing capacity while minimum fuel usage.

Modelling of coal dozing with spherical particles

Contact

Prof Jeff Loughran
School of Engineering, James Cook University

Industry Contact

Barry Koster - Managing Director
Jaws Buckets and Attachments Pty Ltd