Design and Construction of a Mining Haul...
Transcript of Design and Construction of a Mining Haul...
Design and Construction of a Mining Haul RoadDr Richard Yeo, Austroads & Max Wallis, Polymix Industries
Steve Runge
Max Wallis
Tom Wilmot
Ian Hentschke
Acknowledgement
Lady Loretta mine
51.5km haul road
13 million tonnes of minerals
8 year life
135 km from Mount Isa
Annual wet and dry seasons
Environment has a greater impact than traffic loading
Guide to Pavement Technology
Pavement design focused on mitigating the risk of saturation of the pavement and subgrade
Construction during dry season
Design Traffic
Design vehicle – quad road train
5 x 106 ESAs
• unbound ‘track’
• running surface directly on the natural subgrade or worn well below this
• alignment varied by creek crossings and areas of black soils
• uneconomic to build up above natural ground
• existing compacted materials adopted
• very high operating costs
Variable subgrade:
• laterite soils
• very reactive black soils
• weathered rock outcrops
Existing conditions
• flooding anticipated during the design period
• possible inundation for up to 2 to 3 days
• road closed during flood events
Pavement inundation
• design involved use of rock won within the road reserve rather than importing material
• criteria included Particle Size Distribution, Plasticity Index (PI), Hardness, Linear Shrinkage
Fit for purpose pavement materials
In situ stabilisation adopted:
• correct mechanical deficiencies (particle size distribution and/or plasticity)
• increase strength or bearing capacity while maintaining a flexible pavement
• reduce permeability and/or moisture sensitivity
• cost-effective new pavement
• use of non-standard gravels
• minimal maintenance
• ease of maintenance
Fit for purpose pavement materials
Dry powder polymer selected on the basis of:
• proven track record – TIPES approved
• enabled a more open grading curve suited to the local materials
• reduced capillary rise
• increased soaked CBR
• increased wet strength
• reduced permeability
• lower water required for compaction
In situ stabilisation
0
20
40
60
80
100
120
140CBR (%)
A B C D EPavement
material:Unsoaked 4 day soaked 4 day soaked - stabilised
Sprayed seal
Binder Shoulders l/m2 Inbound l/m2 Outbound l/m2 Aggregate
S4.5S 1.7 1.4 1.0 10 mm
S4.5S 1.9 1.7 1.4 20 mm
Prime: AMC00: 0.8 l/m2
Sprayed seal
In summary
• 51.5 km
• 510,000 t crushed base and subbase
• dry powder polymer in situ stabilisation
• $510,000 per km