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HAUL ROADS
transient nature of many haul roads often
means the scale of investment is not recovered
from increased all-weather resilience and fleet
up-time.
Work in Western Australia is currently
underway using conventionally-constructed
(unsealed) gravel surfaced mine haul roads to
isolate those factors that differentiate a resilient
road from a more vulnerable road. Using these
characteristics, an analysis of the sustainable
economics of the construct/maintain/
rehabilitate decision evaluates the cost and
practicality of options identified to increase
resilience, against the benefits described above.
Mine Haul Road Optimisation Alliance
The Mine Haul Road Optimisation Alliance
(HROA) is an Australian industry-academia
collaboration which has been developed to
support mine haul road operators by fully
integrating mine road design research solutions
with industry end-user service providers to
design, assess, implement and monitor the various
equipment, materials and road management
strategies required to optimise the safety,
environmental and economic performance of a
haul road. The group includes Proof Engineers
(PE); RoadSafety Training Services (RSTS);
Australian Diversified Engineering (ADE), and
Reynolds Soil Technologies (RST).
An example of informal collaboration between
HROA and academia through Roger Thompson’s
Curtin University Western Australian School of
Mines Mining Engineering and Metallurgical
Engineering (WASM ME2) is in the development
of design guidelines for the discussed wet
weather trafficability issue and skid resistance
of mine haul roads. This work stems from an
Australian Coal Association (ACARP) 2015
research priorities listing under: Mining – Opencut, seeking “improving the productivity of
trucks (uptime in wet conditions); and
improving equipment operator interfaces,
collision avoidance, improved automation and
remote control.” The collaboration was
presented at SME 2016 in Phoenix.
The paper states: “Haul road wearing course
material selection and engineering guidelines
developed through collaboration with HROA will
assist in defining ‘high-risk’ wearing course
materials, increase haul road up-time in adverse
climates (ie minimise re-mobilisation times),
facilitate the use of sub-standard construction
materials to improve wet trafficability and
reduce haul road provision, road maintenance
and road-user costs.”
Whilst guidelines exist for haul road wearing
course selection, construction and maintenance
for semi-arid environments and materials,
surface mining in tropical/challenging
environments is characterised deep weathering
and regolith, such that suitable road
construction materials are not always readily
available and, when coupled with higher
frequency and intensity of rainfall, results in
excessive haul road down-time and delays in remobilisation.
The research methodology involves an
analysis of the engineering characteristics of a
number of open-cut mine site haul road wearing
course materials and the associated skid
resistance and wet trafficability. Through RSTS,
skid resistance test data already exists for many
sites, but has yet to be referenced to wearing
course material engineering controls and
selection parameters.
Collaboration for this particular project
involves both the use of existing RSTS data,
supplemented with additional site wearing
course sampling and in-situ strength
evaluations, initially through technology and
process transfer from WASM ME2 to RSTS,
followed by skid resistance performance data
transfer from RSTS to WASM ME2,
supplemented with site production data, to
identify the characteristics and construction and
road maintenance requirements of wet-weather
resilient wearing course materials.
“The methodology is focused on a site-based
approach to data collation and assessment so
that wearing course material factors
contributing to wet-weather down-time and poor
friction supply are grounded firmly in current
practice and infrastructure, and will provide a
sound basis for expansion, enrichment and
validation of the wearing course selection
guidelines and engineering controls developed.
It is this overall process that the HROA
collaboration facilitates, where the industry
data, per se, has no value in the creation of new
knowledge until it is synthesised with additional
parameters and analysed through the research
process, to generate the new knowledge
required. The guidelines and engineering
controls thus produced are fed back into the
HROA for further development and application,
for example through ADE, RSTS and PE.”
Caterpillar’s views on haul roads
Kent Clifton, Mining Applications Specialist, at
Caterpillar Global Mining says of haul roads:
“The critical variables are influenced by mine
planning and operations management, but every
aspect of truck haulage offers continuous
improvement opportunities for miners. Proper
road design is the first step in ensuring good
truck productivity and low operating costs.
Critical elements are grade, cross-slope and
superelevation of curves. The goals are to
maintain proper weight distribution of the load
and to minimise lateral forces on tyres. The
same design that enhances truck productivity
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JUNE 2016 | International Mining 49