Best-Chem resolves dusts issue at Hanson Ystrad Meurig Quarry
In Early 2007 Hanson Aggregates decommissioned its crushing and processing plant at its Ystrad Meurig Quarry nr Aberystwyth. This was replaced with a complete mobile crushing and screening plant supplied by Metso Minerals. The new plant has a capacity of processing some 500,000 tonnes of greywacke stone per annum.
The crushing plant is fitted with water sprays at the head of the conveyors bringing the stone to the crushers in order to wet the stone. However, these sprays have a very limited effect in suppressing dust and there was clearly a serious dust issue that had to be addressed. The high level of fugitive dust was causing concerns relating to:
- employees' health
- the local environment
- vehicles operating in the quarry.
Best-Chem was approached in early June 2007 to see what solution could be offered in these unique circumstances. Adding more water sprays was not the answer - not only was the dust problem not being solved but the screens were blinding over.
Given the fact that this was a truly mobile installation an imaginative and innovative solution was called for.
Having surveyed the site it was clear that the dust suppression systems also needed to be "mobile" and be capable of being moved with the crushing plant. In addition given that the working area was very exposed it became apparent that the options were somewhat limited.
A mobile Foam Dust Suppression System was recommended and a full scale trial was offered using Best-Chem's Mobile Foam Generating Unit. The trial was carried out in mid June and based on the results (see before / after photos) Best-Chem was commissioned to design, build, supply and install an integrated "trailer mounted mobile foam system".
The first ever Mobile Foam System was delivered in the first week of September. The System is housed in an enclosed "Ifor Williams" twin axle trailer with roller shutters at one end and a personnel door at the other. The System comprises
- Best-Chem's unique Foam Generating Unit
- Air compressor
- Chemical storage tank
- Control panel
- Hose reels for foam delivery hoses
- Easy cam lock fittings for foam and water supply hoses
- Weather proof IP65 rated power and control connections on the exterior of the trailer.
The System is fully automated and its key features include
- Capability of applying foam at up to six different locations around the mobile crushing plant
- Low power requirement which is taken from the auxiliary supply of the mobile crushers
- On / Off signal taken from the belt scales on the conveyor leaving the primary crusher. This ensures that foam is only applied when there is material being processed and does not require any operator intervention once the System is switched on at the beginning of the day.
- Chemical supply taken from a 1,000 litre IBC which is housed in the rear of the trailer. The IBC is connected with easy operated camlock fittings which ensure that there are no spillages.
- Foam application rate can be easily adjusted to suit prevailing weather conditions. If the weather has been persistently wet the flow rate can either be reduced or turned off at one or more application points.
- Specially designed nozzles which allow the foam to be applied consistently attached to the crushing plant with easy removable fittings so that they can be taken off when carrying out maintenance.
- Flexible rubber hose used for delivery of the foam with camlock fittings for quick and easy removal and re-installation.
- Efficient interior design of trailer allows easy access to all components making the maintenance task easier.
- Trailer fitted with standard tow bar including lights allowing the system to be moved around the quarry with ease and also to another quarry if required.
The Mobile Foam System delivers approximately 20 litres of solution per minute (150 parts water and 1 part Dustrol - Best-Chem's proprietary foaming and binding agent). This solution is converted to foam as it travels down the rubber hoses to the five application points. The foam is applied
- directly in the jaws of the primary crusher
- at the head end of the conveyors taking material to the secondary and tertiary crushers
- directly in to the secondary and tertiary crushers.
The result of the foam application can be seen in the photos below. Up to 95% of the fugitive dust is captured in the crushing process. The low level of moisture added in this process ensures that the screens do not get blinded over nor is there any contamination with dust sticking to larger stone sizes.
The Manager at Hanson's Ystrad Meurig Quarry Simon Swinford was happy with the response and advice offered from Best-Chem who delivered a Mobile Foam System to solve their dust problem. He added that "the initial trial was quite impressive; it didn't take long for the foaming system to take effect when switched on. The mobile unit since supplied is very easy to move around the site and at such an early stage is proving very effective in combating the air borne dust produced from the crushing and screening process".