The wet season presents challenges to even the most efficiently run iron ore mine. Both productivity and profits are negatively impacted whenever there are extended periods of rain. Staff and expensive machinery are forced to sit idle, waiting for the weather to pass.
Rain is a particularly prominent concern in relation to a mines' haul road network. Wet weather is a leading cause of underperformance of haul roads and has an impact on mining productivity and road-related costs. Movement of ore from the pit to stockpiles are affected due to visibility issues and poor rolling resistance.
Valuable time that should be used for the actual transportation of iron ore is instead spent fixing slippery and muddy roads. This often leads to targeted trips not being made according to set schedules.
It can therefore be concluded that productivity, the safety of operations and equipment life all depend on a properly designed and well-maintained haul road network.
Improving bounce back after a wet weather event
Whilst there’s not a lot that can be done during adverse weather conditions, it’s a different story once the skies have cleared. Bounce back can vary greatly depending on the strategy adopted in the post rain clean-up period.
When the downpour ends on an iron ore mine site, the graders come out to grade the muddy mess off the top of the haul roads in an attempt to dry them out to prepare them for safe use again.
There are five main problems with this approach:
- The mine loses even more production time
- The grader destroys much of the road surface material
- The haul roads must be rebuilt once the materials are dry
- Additional work may need to be undertaken such as cleaning out drains
- Materials that have washed away have to be replenished
Each problem takes time and costs money – neither is a good outcome for the mine.
Delays and costs can both be minimised with a little forward planning. After all, the next wet season will always come around. Iron ore mines can implement solutions to improve bounce back, creating a more efficient process for future weather events.
A more stable haul road leads to a faster recovery time
During a substantial rain event, water often begins to pool and is then absorbed into the road surface. This can happen quite quickly and lead to the compacted top layer of the wearing course – the fines and pavement material - washing away and exposing the larger, coarser rocks in the sub structures. This is not an ideal surface for road haulage and will inevitably lead to uncontrolled tuck movements as well as tyre blowouts.
In order to stabilise and improve the running surface of haul roads, iron ore mines can apply spray-on treatments which contain binding and sealing properties such as Dust-A-Side’s flagship product - DAS Product.
What is DAS Product and how does it improve haul road bounce back after rain?
DAS Product is an emulsion of bitumen in water, specifically designed and formulated to physically bind road materials together to suppress dust in dry weather and dry substantially faster after wet weather than unsealed roads.
After application the surface water is shed, rather than pooling or being absorbed. This makes for a faster wet weather recovery time.
Along with application of the DAS Product, Dust-A-Side recommends road camber to ensure that water is shed from the surface to the edges of the road, as well as sufficient drainage to get the water away from the sides of the road and prevent it from soaking back into the sub layers of the pavement.
These services are all part of Dust-A-Side’s holistic haul road management solutions.
Waterproofing roads improves efficiency – whatever the season
Whether it’s minimising the damage to roads in the wet season or reducing the need for water carts on the road in the dry season, waterproofing makes sense for any iron ore mine.
Waterproofing mine roads will decrease downtime and increase productivity after the rain as well as reduce on-going haul road maintenance costs compared to relying on unsealed roads.
Mine operators can greatly reduce the washout of fines and good quality wearing course material, as well as the ingress of water into the sub layers of the pavement. Haul truck drivers will find there are fewer soft spots and potholes on the road network, which means less maintenance and more time for hauling.
Implementing solutions to stabilise haul roads is ultimately all about improving bounce back with the least amount of interruption – all year round and no matter the weather.
Here’s what some of our customers have to say:
“We can start up 20 – 60 minutes after the average rain event on Dust-A-Side roads with production at about 50% of capacity and 100% capacity when the non Dust-A-Side roads are graded or dried adequately. The recovery time difference between Dust-A-Side and non Dust-A-Side roads is around 1.3 to 1.8 hours as it takes longer for non Dust-A-Side roads to dry to a point where they can be graded/re-sheeted.”
- Mining Manager, Anglo American
“Dust-A-Side roads offer a huge benefit during heavy rainstorms as these roads stand up well to wet conditions allowing less production disruptions as a result of inclement weather.”
- Head of Production, BHP - WAIO
“In general, the main haul road is trafficable sooner after rain events. A 144mm rain event post Dust-A-Side had a 24-hour recovery versus a pre Dust-A-Side 150mm rain event for 80 hours recovery.”
- Technical Services, Anglo American
“After rain events, Dust-A-Side surfaces dry faster than untreated surfaces providing a higher level of surface friction more quickly.”
- Managing Director, Road Safety Training Services
Interested in learning more about stabilising the haul road network at your iron ore mine?
Simply get in touch with us today or click here to arrange an on-site technical consultation and report.
We’ll provide you with a detailed cost analysis based on the size of your haul road network.
We’ll also provide you with figures showing how soon you’ll break even by engaging our services and how much you will be likely to go on and save on operating costs.