Charles Sturt University
Charles Sturt University

Mine Site Operations: Rock Fragment Size Detection in Drawbells (Rock Piles)

Industry Partner: Newcrest Mining Ltd 

J. Gao, M. Antolovich, A. Benter

Background

After blasting, a Load Haul Dump (LHD) loader collects the broken ore which is then taken to the primary crusher to further reduce the size of the ore material. The ore material should be small enough to pass through the crusher otherwise large fragments will jam the crusher creating a bottleneck in the production line.

The driver of the extraction vehicle makes an assessment of the size of the fragments at the draw. If a fragment is too big for the primary crusher, the collection of the ore material is suspended and the area is closed until a secondary crusher crew arrives to break the large fragment.

Cadia East Cave 1 Primary CrusherCadia East (near Orange) Panel Cave 1 Primary Crusher (Image: Newcrest Mining Limited)

The Challenge

The driver can only see large fragments at the surface in the draw as shown in the following figure.

Draw Point in an Underground MineDraw Point in an Underground Mine

The challenge is to determine whether large fragments that cannot be seen are present inside the pile before the LHD vehicle arrives.

Method

Ground Penetrating Radar (GPR) is an imaging technique that uses radar pulses to probe the subsurface.

GPR unit  Chris Lewis from the CSIRO Materials Science and Engineering Division demonstrating the use of a GPR unit (Image: Newcrest Mining Research Laboratory - CSU)

GPR was used to identify large fragments within the pile by looking at the reflected radar signal: small fragments surrounded by air pockets have a different electromagnetic signature compared to a large rock fragment. The group developed sophisticated algorithms to refine and enhance the analysis of the GPR images.

Benefits

Identifying large fragments at the draw point before collection of the ore allows the operators of the mine to plan the closure of the draw, prevent unnecessary vehicle movements, and equipment shutdown. This technique reduces costly shutdowns and enables a more efficient operation of the mine site.

Selected Publications

  • Benter, A.; Antolovich, M.; Moore, W., "Determining bulk density of mine rock piles using ground penetrating radar frequency downshift, "6th International Workshop on Advanced Ground Penetrating Radar (IWAGPR 2011)", vol., no., pp.1,6, 22-24 June 2011.
  • Benter, A.; Xu, R.; Moore, W.; Antolovich, M.; Gao, J., "Fragment size detection within homogeneous material using Ground Penetrating Radar", Radar Conference – Surveillance for a Safer World (RADAR), pp. 1-5, 2009, ISBN 978-2-912328-55-7.

Research papers are not for general public distribution.

Contacts

Prof. Junbin Gao, Dr Michael Antolovich, Dr Allen Benter
School of Computing and Mathematics, Charles Sturt University

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