July 22, 2017

Tackling hazards particle by particle

dust-suppression-2

Managing dust on haul roads in mines still remains a challenge despite “cutting edge” products that are being released regularly to make the task easier. African Mining Brief finds out from Sebastian Karsas, an extensively experienced dust control expert from dust control solutions developer, 88Chemco, about factors behind this worrying trend.

In spite of an appreciable level of commitment to comply with requisite dust control obligations on haul roads, worryingly, reports indicate that lapses on mining sites in most African countries are still persistent. Interestingly, some, if not most of the oversights, would require what could be considered “routine” interventions to be adequately addressed. So, possibly, what could be going wrong?

This state of affairs should not be entirely surprising,says Sebastian Karsas.

After years of consulting in dust control requirements for mines globally, lamentably, he has noticed that sites have three common challenges.

Firstly, inundated by hundreds of products which are on the market, mines are finding it difficult to ascertain the veracity of claims by some marketers and make rational decisions on which solutions would address their specific dust control requirements effectively, Karsas notes. “You would find a product being punted as a cure-all solution while it just won’t deliver the required results.”

Secondly, some organisations face problems in establishing which particular products are appropriate for their temporary and permanent road dust control requirements. According to Karsas, this is because products can be different both in chemistry (composition) and application.

Thirdly, a vital but often misunderstood area in dust control is re-surfacing and road material management. Yet, as roads deteriorate, they need to be resurfaced with material. The correct selection of this material is of high importance.

Informed decisions

To address the aforementioned issues appropriately, Karsas suggests the adoption of two main interventions, as any oversight might result in waste of invaluable resources and increase in miners’ exposure to hazardous dust.

“Firstly, a mine should ensure that it acquires a cost effective product that is specific to its needs on haul roads,” he says.

“With reference to temporary and permanent road requirements, understanding what material is available is very important because, if for example, the silt content is too high it will create a major dust problem. This simple but effective method of managing surfacing materials can reduce major dust problems significantly.”

dust-suppression

Why low compliance?

Ideally, new legislation, which underlines zero tolerance, correspondingly, should lead to better compliance in mines, but, in reality, it has not. One might ask: Why is this the case?

Karsas has identified two main factors – lack of specific impact contribution and a requirement for better information surrounding dust control and the associated products.

  • Lack of specific impact contribution

One plausible explanation behind poor compliance, Karsas says, is that it is difficult to apply any ambient legislative requirements, specifically to haul roads, as there is typically a general rule for dust emissions at the boundary of the mine in a concentration/m3/24-hour average. Basically, this encompasses the total contribution from the mine activities i.e. culmination of loading, hauling, dumping, blasting etc.

Nevertheless, Karsas points out, for roads which are known to have a high impact contribution, a benchmark (measuring method) for compliance has not been established. And as a consequence, it is a challenge to isolate particular activities such as hauling in terms of compliance. Thus, he believes that a specific impact contribution would help mines identify sources of dust at the boundary.

  • Requirement for better information

Minimal access to information in the industry is resulting in lower compliance. This can be reflected by the way dust suppression is viewed. It is often considered noncore to business and an annoyance, which is a drag and drain to their overstretched financial resources at the present time.

Although cutting edge technology is available, all products come at a cost and the allocation of resources to manage the dust doesn’t have to impact on opex/capex significantly.

These challenges, Karsas proposes, should be managed in two ways.

“Concerning dust control solutions, mines should do their homework and ensure the company they are dealing with isn’t selling just one product but rather a variety that is purpose orientated.”

“To remove the burden of dust control from their operations, mines should assign dust control specialists, for them to provide knowledge, expertise and products, while they focus on their core business,” he explains.

The “multipurpose” myth

How often have we heard about products being flaunted as multipurpose? Karsas cautions that claims of a solution being supposedly versatile should always be taken with a pinch of salt.

“Just because there are types of products that can be used in all types of dust suppression and will effectively mitigate dust, that doesn’t mean they are the best,” he says. “For example, you could use a bitumen based product to stop dust on a road and it will, but it may not be the most cost effective. It may not be suitable on that particular road as there are other chemistries that can have the same performance at a much better cost to the client. There is much more than just applying a product to stop dust.”

“Fine particle” engineering

The merits and demerits of a number of dust control systems have been proven in demanding conditions. However, through “fine particle engineering”, says Karsas, the available chemistries applicable to a mine’s dust control needs can be assessed accurately, mainly encompassing:

  • Effectiveness to stop dust
  • Environmental approval
  • Cost per unit
  • Logistical requirements
  • On site application challenges

Eventually, the client would understand what is available, the expectation, and what is involved before purchasing.

Mobile dust monitor

Meanwhile, undeterred by effects of weak commodity prices, original equipment manufacturers are not slackening. And one such organisation is 88Chemco which, recently, developed a mobile dust monitor that can be installed onto a bakkie. Whilst driving on haul roads, the mobile dust monitor measures dust and presents a colour scale printed on the site map to indicate which roads are dusty assisting in better dust management. This is now part of their haul road management system which is a turnkey solution, including water bowsers, graders, dust suppression product and monitoring equipment.

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