Using Mining Waste On Roadworks

With a lack of suitable road-building materials on the Great Northern Highway between Halls Creek and Warmun, a trial was undertaken in the Kimberley Region to use mine waste rock from a local nickel mine.

Due to a lack of suitable road-building materials on the Great Northern Highway between Halls Creek and Warmun, a trial was undertaken in the Kimberley Region using mine waste rock from the Savannah nickel mine. This material was crushed to produce a rock-base pavement material and was blended with suitable local naturally occurring materials.

Laboratory testing on trial materials ascertained the best performing blend ratios and an 800-metre trial section was selected on the Ord River Bridge approach at the southern end of the work site. The trial section was constructed in two parts, each 400 metres in length; one part was constructed by grader and the remaining part by rotary hoe, with both sections then being sealed.

The new pavement has been used for 12 months and has been subjected to above average rainfall and continues to perform well. Some of the benefits from using this material are:

  • The large quantity of material available (500,000 tonne) at the location, so one crushing and screening contract can be established to deliver material for several projects at once.
  • The absence of delays through seeking environment and heritage approvals.
  • Premium-grade pavement material is used in an area of the road network that carries very heavy vehicles associated with mining activities. This should reduce maintenance.
  • Costs are reduced as the mine site is in the area of need. Suitable naturally occurring base course gravels are very scarce and would otherwise have to be sourced from locations with longer cartage distances and higher costs.
  • Construction costs are reduced because this material will not need stabilising, in contrast with other local materials that are generally substandard and require cement stabilising.

Testing continues and if results remain positive we can explore opportunities to expand this approach where it is an appropriate and viable solution.