The most common dust control method employed by mine operators for haul roads is the regular use of water carts 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 Australia at any time of the year will happen in a matter of minutes not hours. This inevitably leads to increased water cart 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 a number of drawbacks including:
- Water scarcity issues (especially in periods of regional drought)
- High operating costs including equipment capital, the people-hours required for operating and the water itself
- High maintenance costs including tyre damage caused by over-watered roads
- Deterioration of road quality due to constant saturation
Alternatives to using water alone for controlling dust on haul roads include adding specially developed dust suppression additives or binders such as lignosulphonates to water carts. These additives work to bind road surface dust particles together. Water evaporates from the lignosulfonate as it dries and the dust particles are trapped by the binding effect left behind.
Many mines around Australia have adopted or at least trialed the use of dust suppression products in their water carts as a total or partial replacement for using only water. The effectiveness of these products for dust control purposes on haul roads has been well-documented. (View our resources page for further evidence of this). However, some mines have found that these products have not worked as successfully as they had anticipated.
In most instances, it is the failure to understand the change in application method required, or adjusting 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 supplier provides insufficient guidance or support
A lack of support, advice or guidance from the product supplier 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 suppliers, false expectations on product performance such as “spray and forget” takes hold. Always look for a supplier 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- The mine is using the incorrect dosage of the product
Over or under dosing the amount of suppression product required for the volume capacity of the water cart will lead to poor outcomes. Under dosing with the product will result in little to no impact of the agent on the haul road – mines will often walk away from the product at this stage disbelieving the performance claims. Over dosing with the product will lead to excessive product consumption, potential equipment damage and mines abandoning the approach because costs are too high.
Suppliers that provide 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 also highly 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, someone at the mine should be responsible for monitoring these changes and adapting the dust control program accordingly.
3 - The mine is over-watering the haul roads
When a mine has relied on water alone for dust suppression over some time and then makes a change 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 a product is being used properly, 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 a suppression product is 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 over-watering roads which increases the occurrence of uncontrolled truck movements. Again, getting support from your supplier to provide operator training 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 finds over time that their resources are insufficient or availability needs to be reallocated to production or other operationally critical tasks. In short, it’s acknowledged that the dust problem must be addressed, but it’s too hard for mines to do it effectively 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 on how effective dust control measures are. Trying to spray suppression products on a badly deteriorated road with drainage issues is an uphill battle no one is going to win.
Additionally, different sections of the network have to 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 suppression products may need to be considered. Specialised knowledge is required to be able to recommend which solution is best to use on which type of road.
Rather than mine operators trying to go at it alone, a dedicated managed service or full service provided by a 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’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 cart operators on how to correctly use dosage pumps.
- Regularly driving around the road network and talking to water cart operators via the radio or sitting in the cab of the water carts 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 mine is on track for product costs and also highlight any mistakes being made by the operators.
Want to improve the effectiveness of dust suppression products at your site? Talk to Dust-A-Side.
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.