The most common dust control method employed by mine operators for haul roads is the regular use of water bowsers spraying water to keep the surface of the road network damp and free of dust.
This method is only effective until the road dries again, which on many mines across South Africa at any time of the year will happen in a matter of minutes not hours. This inevitably leads to increased water bowser activity to keep the roads damp but will also lead to increased operating costs and potentially unsafe roads if over wetting occurs. Mines therefore are increasingly looking for alternatives to just spraying water. This is because reliance on water alone has several drawbacks including:
- Water scarcity issues
- High operating costs including equipment capital, the people-hours required for operating and the water itself
- High maintenance costs including tyre damage caused by overwatered roads
- Deterioration of road quality due to constant saturation
Alternatives to using water alone for controlling dust on haul roads include adding specially developed road dust suppression chemicals or binders such as lignosulphonates to water bowsers. These dust palliatives bind road surface dust particles together and thus allow water to evaporate leaving the residual lignosulfonate as it dries and the dust particles are trapped by the binding effect left behind.
Many mines around South Africa have adopted or at least trialed the use of dust suppression products in their water bowsers as a total or partial replacement for using only water. The effectiveness of this product for dust control purposes on haul roads has been well-documented. View our resources page for evidence of this. However, some mines outcome was not as satisfactory as anticipated.
In most instances, it is the failure to understand the change in application method or having not adjusted the maintenance program, not the products themselves that is the cause of poor results.
Here are four common reasons dust suppression products fail to work on haul roads:
1 - The product and service provider provides insufficient guidance or support
A lack of support, advice or guidance from the product and service provider on how best to use the dust suppressant purchased and what to expect from the product often leads to the other common reasons for failure presented in this article.
Unfortunately, in the absence of suitable support from the service provider, false expectations on product performance such as “spray and forget” takes hold. At all times look for a service provider who provides clear instructions and expectations on product performance, has the capability to provide site-based application services and demonstrates a strong background in haul road dust control applications.
2 - Mine is using incorrect dosage of product
Over or under dosing the amount of dust suppression product required for the volume capacity of the water bowser will lead to poor outcomes. Under-dosing products will result in little to no impact on the customer’s haul road – mines will often walk away from the product not believing the performance claims. Overdosing dust palliatives will lead to excessive product consumption and mines abandoning the approach because of excessive costs.
Product and service providers that offer application training, infrastructure for product storage and transfer and help their clients develop an ongoing dust control maintenance program to direct the spraying activities will help mines avoid this problem. Using controlled product dosage pumps and remote telemetry systems on product tanks are recommended to help control and monitor product usage. It’s also worth noting that the required product dosage may change throughout the year due to weather patterns, haul road usage or equipment changes. Ideally, dedicated personnel at the mine should be responsible for monitoring these changes and adapting the dust control program accordingly.
3 - The mine is overwatering the haul roads
When a mine has relied on water alone for dust suppression over some time, and then switches to using dust suppression products, the continual spraying on roads can become a difficult habit to break. Mines get used to spraying a road when it’s dry, but when dust palliatives are sprayed at the recommended applications , a dry road won’t mean a dusty road. In fact, a treated road which is dry is the best outcome!
Mines don’t need to continuously re-water treated haul roads throughout a shift when dust palliatives are being used. Typically, roads only need to be watered once or twice during a shift, provided the correct dosage of additive has been applied. If the mine fails to make a change in their spraying procedures or continues to use water only after dust control treatments have been applied, they risk diluting the treatment, consuming more product or overwatering roads which increases the occurrence of uncontrolled truck movements.
Again, getting support from product and service providers, train operators and providing a programmed maintenance service or a dedicated supervisor to oversee the haul road maintenance will help eliminate this problem.
4 - The mine lacks the resource or ongoing inclination to focus on managing haul road dust control
Too often we hear of a mine purchasing bulk quantities of a dust suppressant under the assumption that they have the capabilities to successfully apply the treatment with their existing labour and equipment. The mine then realises over time that their resources are insufficient or needs to be reallocated to production or other operational critical tasks. In short, it’s acknowledged that the mine’s dust problem must be addressed, but it’s hard or not always possible for mines to do it effectively and efficiently themselves.
For example, haul road networks often change with the evolving nature of mining and these roads need constant maintenance to keep trucks operating efficiently and haul cycles maximised. The changing condition of a haul road will directly impact the effectiveness of the dust control program. Trying to spray dust palliatives on a badly deteriorated road with drainage issues is an uphill battle no one is going to win.
Additionally, different sections of the network must cope with different levels of traffic. One type of dust suppressant or binder which is specially designed for permanent, high traffic primary haul roads will not be effective on temporary or low traffic service roads. A combination of dust palliatives may need to be considered. Specialised knowledge is required to be able to recommend a fit for purpose solution for a specific road.
Rather than mine operators trying to go at it alone, a dedicated managed service or an experienced leader in the industry should be considered.
How a managed service will guarantee the effectiveness of dust suppression products on haul roads.
A managed haul road service will mitigate the most common reasons dust suppression products fail to work on haul roads.
As part of Dust-A-Side South Africa’s managed service offering, a highly experienced on-site project supervisor will be responsible for:
- Implementing change management to prevent overdosing. This includes comprehensive training and supervision of water bowser operators on how to correctly use dosage pumps.
- Regularly driving around the road network and talking to water bowser operators via the radio or sitting in the cab of the water bowsers to deliver one-on-one training, in order to coach them as to where they should/shouldn’t be watering. They have the experience to know how and when roads should be treated with suppression sprays.
- Identifying sections of a haul road network which can be improved upon through maintenance work on a day-to-day basis.
- Providing site reports on how much product is being used in order to qualify whether this usage aligns with the project management plan. These reports will highlight whether the actual product used is in with the recommended one and also highlight areas requiring further improvement.
Want to evaluate and improve the effectiveness of your current road dust control program on your site? road? Talk to Dust-A-Side South Africa.
We understand the numerous challenges faced by mines in relation to dust suppression on haul roads.
The aim of our services is to be on site for as long as a mine exists to help decision makers ensure a haul road network is as effective and cost-efficient as it can possibly be.
To learn more about our managed service solutions, click here to arrange a no obligation technical consult and report.