Dust Suppression Solutions.

Traditional haul road dust suppression has been to use water carts. The disadvantages of this approach are the high ongoing cost of water carts and the labour to operate them. Wet Earth offers an automated sprinkler solution using high quality sprinklers, valves and an automated control system.

The addition of wetting agents and polymer binders to the water used for haul road dust suppression can decrease both the application frequency and the amount of water required. The wetting agents improve the performance of the water in wetting the surface material thoroughly. The polymer binders cause the surface particles to hold together reducing their likelihood of becoming airborne (dust). It also makes the haul roads more compacted with less loose surface material. Dust suppression chemicals can be used with both water carts and sprinkler based solutions.

Increasing the moisture level of material through pre watering can reduce the dust generated by mining and blasting. Wet Earth has a range of high volume sprinklers for this operation.

Above ground mining and blasting in particular generate large amounts of airborne dust. The only solution to suppress this large scale open air dust once it is already airborne are Fog Cannons ™. Fog Cannons™ are high volume mist generating machines with throw distances of up to 250m which blanket the area in a fine mist which suppresses any airborne dust. They are designed specifically for this type of large scale airborne dust suppression. Wet Earth is the exclusive distributor of Fog Cannons ™ in Australia.

Stockpile dust suppression is simply a case of stabilising the surface of the material. This is usually done with regular watering. Wet Earth has a range of long throw, high angle sprinklers which are suitable for stockpile dust suppression. We can also provide the full solution including sprinklers, valves and control system.

In cases where either the material can not get wet or the action of adding or removing material generates an unacceptable amount of dust then Fog Cannons ™ are the recommended solution. Wet Earth is the exclusive distributor of Fog Cannons ™ in Australia.

When using either high volume sprinklers or Fog Cannons the addition of a polymer based crusting agent can dramatically reduce the frequency of application and also improve the dust suppression performance in high wind conditions.

Once dust is airborne then a misting based solution is most practical approach.

For small scale applications then misting nozzles can be used. Wet Earth offers two types of misting nozzles to suit different applications

- Hydraulic atomising misting nozzles are the most common misting nozzles. They require a well filtered high pressure (10-20bar) water supply. They can also be supplied as cluster nozzles where large amounts of mist are required ;

- Air assisted ultrasonic atomising misting nozzles are a newer approach and use a combination of water (2-5bar ) and compressed air (2-5bar) to make a fine mist. These nozzles have a smaller droplet size which improves dust suppression performance and a large mist cloud. They also only require low pressure water, but they require a supply of compressed air.

For large scale applications then a Fog Cannons ™ is the most practical solution. Pointing one of the smaller Fog Cannons directly where the the high concentration dust is being generated is a very successful approach.

To improve the performance of misting dust suppression an ionic wetting agent can be added to the water. The ionic element can be selected to improve the attraction between the dust and water particles and the wetting agent increases the likelihood of the water and dust particles combining.

The action of dumping can generate a large velocity of air which can result large amounts of airborne dust. The use of nozzles spraying water opposing the exiting air/dust can reduce the amount of dust.

In cases where spray nozzles are not practical or do not adequately suppress the dust then a misting solution needs to be used to address the airborne dust. See the solutions recommended for Dust generated during and transfering, discharging, crushing and processing.

The most efficient approach for dust suppression of conveyor belts and transfer points is to build a structure to physically contain the dust.

Where physical containment is not possible then reducing the materials likelihood to suppress dust is a preferred first option. This can be done by increasing the materials moisture level or by putting foam on the top of the material. Increasing the moisture level can be simply done by an array of nozzles or cluster nozzles over the conveyor applying an appropriate amount of water to increase its moisture level so that it is less likely to generate dust. The addition of wetting agents to the water can be used to improve the thoroughness of wetting. Applying a foam coating to the material can also reduce dust creation. The application of foam requires specialist nozzles spraying water with a foaming agent additive.

When dust is generated at transfer points and the the wetting/foaming is not appropriate or successful then the approach used in Dust generated during and transfering, discharging, crushing and processing should be used.

In cases where there is a desire to wet the area (ie fire protection, water disposal) then a network of sprinklers can be used. Wet Earth offers an automated sprinkler solution using high quality sprinklers, valves and an automated control system.

In most open areas it is possible to prevent the dust becoming an issue through applying a dust suppression chemical spray.

In areas where there is no vehicle movement a polymer based crust can be used. If the surface is not disturbed then this can provide from 9 to 18 months of dust control. This crust is water permeable and allows plants to grow through it.

In areas where there is high vehicle traffic then a biodegradable vegetable oil based water spray can be applied. This solution gives up to 3 months control of dust.

In cases where it is not possible to prevent the source of the dust through water or chemicals then the Fog Cannon ™ is the recommended solution. Wet Earth is the exclusive Australian distributor of Fog Cannons ™.

The control of underground dust generated by vehicle movement is usually based on wetting the surface to minimise the dust. For large areas then high volume sprinklers can be used. For smaller areas and underground haul roads then either roof mounted sprinklers (Senninger i-mini-Wobblers) or wall mounted sprays (PNR J type nozzles) are appropriate solutions.