A well maintained haul road network is the backbone of any South African mine, so its condition and subsequent productivity needs to be kept at an optimal level. Therefore, high maintenance and operating costs for haul roads is quite often accepted as a necessary burden by the mine operator.
A major contributing factor to high maintenance costs is the tendency of mine sites to rely solely on spraying water using water bowsers for dust control purposes. This approach is often seen as the easiest and most cost-effective solution.
However, when haul roads require constant watering to keep wheel-generated dust down, mines (and especially large open cut operations) need to invest in a significant water bowser fleet (with associated running costs) to keep the roads dust free. Constant watering also rapidly degrades the road wearing surface. Excessive watering will wash away the compacted top layer of the wearing course – the fines and pavement material – which exposes the larger, coarser rocks in the sub structures below.
Additionally, excessive water will sit on roads with poor shape and drainage and will eventually seep through the pavement and into the sub-base structures over time, causing further road failures.
To repair these failures, graders are required to remove contamination, repair defects such as potholes, corrugation and rutting on the road frequently. This drives up the road maintenance opex further. Once repaired, roads inevitably dry out again, they need to be watered again. And so, the cycle of constant watering and the need for maintenance works continues.
For mine operators wanting to reduce road maintenance costs and increase profits, there are more effective dust control solutions available.
Rather than continuously spraying water on haul roads, mines should consider the use of specialised road binders (such as DAS Product) to actively reduce the amount of water which needs to be sprayed on roads.
There are a range of dust control sprays and treatments available such as lignosulphonate binders, bitumen emulsions and synthetic polymers. These products are usually supplied in a liquid form, ready to use and diluted in water bowsers on-site to the required application concentration.
These formulations are much more effective at suppressing dust than plain water and can reduce water usage by up to 90%. Furthermore, when used at the correct dosage levels at correct intervals, mines will realise a significant reduction in the frequency of spraying required.
As demonstrated in the video below, rather than having water bowsers running 24/7, a mine using binder products can instead expect to only require water bowsers to spray roads once or twice over the course of a shift.
Dust suppression binders work by binding road surface dust particles together. Once sprayed onto surfaces via a water bowser, water evaporates, then the solid content of the product is left behind as it dries. The soil particles are subsequently bound together and sealed into the road surface.
With bitumen emulsions and polymers, a water impermeable seal is also formed so that roads remain dust and mud free in all weather conditions. Preventing water ingress over time also helps reduce road defects such as potholes, corrugations, and rutting.
As haul road networks are not continuously being over-watered, roads do not degrade as quickly as they would when they were being sprayed with water, which further saves on grading, general surface repairs and road re-capping costs. Consequently, maintenance opex is significantly reduced.
An additional benefit for mines which adopt the use of binders as dust palliatives is being able to reduce the size of water bowser fleets or increase the equipment availability of a smaller fleet. Mines can also redeploy water bowser operators to perform other, more high yielding activities, such as operating mine equipment in production.
Simply click here to arrange an on-site technical consultation and report.
We will provide you with a detailed cost analysis based on the size of your haul road network.
We will also provide you with figures showing how soon you will break even by engaging our services and how much you will be likely to go on and save on operating costs.