A phosphate mine in Morocco has tested a haul-road pavement made entirely from waste rock produced during phosphate extraction, according to the study.
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mine → test → study
Researchers examined whether the material could withstand the extreme loads created by mining trucks while also reducing dust from the road surface.
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material → examine → surface
They designed a three-layer pavement using crushed phosphate mine waste rock and phosphated flint.
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They → design → rock
According to the research published in Mining, titled ‘
Innovative Pavement Design for Heavy-Haul Mining Roads Using Phosphate Mine Waste Rock: Dust Emission Control, Mechanical and Operational Performance Improvements’, the pavement included a 0.35-metre sub-base, a 0.25-metre base and a 0.07-metre asphalt wearing course.
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pavement → accord → base
How did the Moroccan mine build a heavy-truck road from phosphate waste rock
Researchers designed the pavement for a heavily trafficked haul road at the Benguerir phosphate mine.
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Researchers → build → mine
The road carries about 22.35 kilotonnes of material each day and is used by large mining trucks.
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road → carry → trucks
The proposed structure had three layers.
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structure → propose → layers
The sub-base was 0.35 metres thick and used crushed phosphate mine waste rock graded from 0 to 100 millimetres.
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base → use → millimetres
The 0.25-metre base layer was made from 0 to 63-millimetre crushed screening waste rock.
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layer → make → rock
The surface layer was a 0.07-metre BBSG 0-20 millimetre wearing course made with phosphated flint aggregates and modified bitumen.
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layer → wear → aggregates
The pavement was designed to withstand permanent deformation and structural rutting under heavy loads while controlling dust and keeping construction costs economically viable at Benguerir.
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pavement → design → Benguerir
How did the pavement perform under heavy mining traffic
Laboratory tests were used to assess whether the proposed materials could withstand heavy mining traffic.
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materials → perform → traffic
The asphalt mixture was tested at three bitumen contents: 4.9%, 5.1%, and 5.3%.
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mixture → test → contents
At 5.1%, the mixture reached its selected balance of mechanical and volumetric performance.
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mixture → reach → performance
It recorded a stiffness modulus of 9160 MPa and fatigue resistance of 139.6 microstrains at failure.
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It → record → failure
Field testing then examined the bearing capacity of the compacted pavement layers.
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testing → examine → layers
The sub-base recorded an average EV2 value of 153 MPa.
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base → record → MPa
The base reached 181 MPa.
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base → reach → MPa
These measurements confirmed the load-bearing capacity recorded in the experimental pavement.
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measurements → confirm → pavement
The new haul-road surface reduced dust and improved visibility
The field trial also measured dust before and after the pavement was constructed.
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pavement → reduce → dust
Measurements covered PM2.5 and PM10 at two locations along the experimental haul road.
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Measurements → cover → road
The unpaved section represented the mine's existing practice, which included daily watering and routine grading.
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which → represent → watering
Its average dust concentration reached 91,730.16 micrograms per cubic metre.
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concentration → reach → metre
After the full pavement structure was installed, the asphalt-treated section recorded an average concentration of 8570.10 micrograms per cubic metre.
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section → instal → metre
The study calculated a reduction of about 91%.
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study → calculate → %
This exceeded OCP Group's target of reducing airborne dust emissions by more than 80%.
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This → exceed → %
The researchers also reported a smoother and more stable road surface after paving, with improved visibility and reduced surface roughness during truck operations.
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researchers → report → operations
How did the paved road affect mining productivity and maintenance
The proposed pavement was estimated to cost about €23.97 per square metre for the experimental section.
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pavement → affect → section
The calculation included the required construction work and a 25% allowance for bulking and wastage.
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calculation → include → bulking
The study assumed the crushing unit would be within 5 kilometres of the works and the asphalt plant within 25 kilometres.
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unit → assume → kilometres
After 15 months of continuous operation under actual mining traffic, an internal assessment by OCP indicated that wider use could produce an estimated annual productivity gain of about 15%.
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use → indicate → %
The study linked the expected gains to higher truck speeds, fewer spare-part replacements, including tyres and wheel motors, longer fleet service life and less daily haul-road maintenance.
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study → link → tyres
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