Mining operations are geared to achieve daily optimal production. But efficiency and productivity can be drawn to a sudden halt, or otherwise dramatically slowed, during and after significant weather events.
Mines will often experience production delays of hours when it rains (or even days at a time during major storm events). Delays will be extended if permanent haul roads have not been built, formed, and shaped well. Flooding and road surface washouts can inevitably occur and prevent quick recovery of the haul road network.
In these conditions, inadequate binding and sealing of the haul road pavement will exaggerate road closures and lengthen road recovery. Additional to further cost to the time delays, it will often be necessary for mining services crews or contractors to scramble to repair, rebuild or potentially divert the haul road to get haul trucks moving again.
As many mine site managers in South Africa will attest, when haul trucks cannot safely navigate haul road networks, just about every step of the production process is affected, causing costly delays for the mine.
What are mines currently doing to mitigate wet weather delays?
While we cannot control weather, there are strategies and solutions that mines can implement to prevent costly production delays caused by wet weather. Despite the availability of such solutions, most mines in South Africa have a ‘wet weather budget’ incorporated into their annual plans. This will account for any stand down days or low production days directly caused by wet or poor weather conditions.
Each mine will apply a site-specific policy to account for wet weather days and how much rain needs to fall before production is halted. For example, one mine may have an allowance of 20 days a year to treat as a ‘write off’ if there is too much rain to continue production, whereas another mine in an area where there is low yearly rainfall may only have an allowance of 10 days.
However, any stoppages can be extremely costly. As noted at the beginning of this article, mines need to operate as productively as possible and tons per hour must be maximised. Just because a mine has rain delays budgeted for, it makes more economic sense to try to minimise any delays and to ‘save up’ these budgeted days for extreme weather events where delays are essentially unavoidable.
Wherever possible, haul roads and especially life of mine roads should be designed, constructed, and maintained to be ‘all weather roads’, thereby truly minimising production delays.
So, while mining operations may have gotten used to the fact that there are annual rain day allocations for lost or low production, it does not have to be this way. There are a range of solutions available that can help mines minimise, or almost eliminate, wet weather delays on their haul road networks.
Here’s a look at two key solutions that mines can implement to reduce wet weather delays
One - Correct road preparation and establishment
As mentioned earlier, many haul roads are designed and constructed without adequate camber, leading to poor drainage.
If carefully designed and built, the road can be established in a way that minimises water pooling and significant flooding after rain events.
To achieve a quality haul road the following should be considered:
- Construction of haul road subgrade and sub-base layers to ensure that the haul road has sufficient underlying strength to support the weight of the loaded equipment that will be travelling along it.
- Incorporation of adequate crossfall and superelevation, as well as appropriate camber for optimal drainage.
- Development of a surface layer (base course).
- Incorporation of a purpose spec road binder and stabilising product (such as DASProduct) into the wearing course layer to stabilise the pavement material and provide a surface seal that won’t allow the ingress of water. This treatment will also eliminate the need for water bowsers to continuously keep the road surface wet to suppress dust during dry periods
Two - Use of road stabilisation technologies and binder products
If the mine roads are already established and well-shaped with good wearing course material, consider introducing a haul road stabilising and binding product to protect and seal the haul road. A stabilised, sealed haul road sheds water and prevents flooding and washouts that contribute significantly to the wet weather delays.
The most effective technologies used to achieve stabilisation are specifically formulated bitumen emulsions for haul roads. They work introducing the binder into the wearing course layer and seal the road to prevent water ingress. Other binder technologies can be prone to leaching or excessive regression in wet conditions.
Proprietary bitumen emulsion technologies (such as DASProduct) allow rapid and even distribution of bitumen content into the wearing course material, which cures and binds material under grading and compaction to form a water-impermeable functional layer. The result is a haul road that drains quickly, is less prone to blow outs, defects or washouts caused by water ingress and will be operational again in a fraction of the time compared to untreated roads after wet weather.
Choosing a reputable supplier such as Dust-A-Side with the capability of delivering a range of application services and road maintenance programs does help our customers and potential customers achieve desired haul road conditions much more quickly and at lower overall operating costs
Benefits of creating all-weather haul roads:
- Quicker road recovery for production.
- Increases to overall tonnage per hour and average daily haul cycles to boost productivity.
- Reduced ongoing haul road maintenance costs.
- Safer running surfaces that reduce uncontrolled movements of haul trucks, thereby increasing safety.
- Reduced water consumption and water bowser costs (95%+).
- Operational dust reductions in dry conditions (90%+)
Looking to reduce wet weather production delays at your site? Talk to Dust-A-Side South Africa
It is never too late to implement all weather road solutions for haul road networks, even if many sections of road have already been long established.
Dust-A-Side can treat all road types on a mine site and are experienced haul road managers and maintenance contractors.
To learn more about our range of holistic dust control services, call us on+27 12 648 8900. Or you can request a no obligation consultation by clicking here.