Emission control is one of the major articles in the February issue. Space constraints resulted in cuts to the Dust-a-Side and ECOLOGY news in the dust suppression article. There was also a consideration of how the sounds eminating from an operation and the look of it can be disguised. SLR Consulting is delivering an exemplary solution to an operation in the UK. A new hill is being developed to block out sight and sound. Don’t forget the water management article in the March issue – we are still accepting interesting editorial contributions to that article. Until next Wednesday.
When properly designed and installed the Dust-a-SideTM High Pressure Mist System produces a high concentration of 10 μm fog droplets. The size of the water droplets provides optimum performance for attraction and
suppression of PM 10 and smaller dust particles. The system can effectively remove breathable and fugitive dust, the company says. Dust surrounded by dense fog has little chance to escape. All systems are customdesigned with corrosion resistant components.
Modular design allows for easy system installation and includes completely programmable controllers with remotely located sensors.
ECOLOGY SRL’s Fog Cannon is another option to tackle airborne particles and dust. The company says “the patented Fog Cannon® suppresses up to 90% of airborne dust particles. It is available for manual use or fully automated to suppress dust in the open air and suppress dust concentrations (loading/unloading trucks, transfer by conveyor belt, unloading hoppers, etc.). The machine emits a powerful fog jet of fine droplets of water/air and, if required, also a surfactant. Two kinds of surfactant are available: agglomerating and film-forming.
Surfactant ECS89 (certified by the German Ministry of Health, VDI 2584 and Ta-Luft.) creates a harmless fog capable of quickly suppressing airborne particles. The film-forming type ECS90 is saline-based combined with natural biological glue. It creates a crust formation capable of containing the dust particles.
There are several models of Fog Cannon available with different projections and reach capabilities: from a range of 30 to 250 m , a rotation angle of approximately 270° laterally and a continuously adjustable height. This
means that a single machine is capable of covering a level area of up to 130,000 m2. Water consumption varies from just 210 up to 1,000 litres/min, while the maximum consumption of surfactant is proportionally set at 1:400 relative to the flow of water.
Similarly, WLP, another Italian company, in order to develop an efficient and lasting system has reduced the size of drops through the nebulisation of water. It has created nozzles which can eject droplets, whose diameter is smaller than 80 μm (mist is made up of droplets with a diameter between 10 and 50 μm and raindrops have a diameter between 1 and 7 mm). In this way, it has managed to maximise the processes of rainout and washout, which are the most effective in dust suppression.
Particles act as nuclei for the condensation of cloud droplets. Some of these droplets become larger and fall to the earth’s surface as raindrops. The particles (condensation nuclei) deposited in this way are said to have been rained out. Washout is the removal of particles by cloud droplets. Particles are incorporated into an already existing drop. The difference between washout and rainout is the pre-existence of a collecting drop.
Mining’s emissions can also be sound and just the look of an operation. SLR Consulting is delivering an exemplary biodiversity offsetting scheme as part of the extension of the 160-ha Bardon Hill quarry in Leicestershire, England. The extension will involve the removal of up to 20 million m3 of overburden and, due to the sensitive location of the operation, the landscape design is forming a key component of the development approach.
SLR’s scheme involves the creation of a new hill to the north of the future working area, which will accommodate all of the initial overburden and help to screen the new operation. Mirroring the landscape in the surrounding Charnwood Forest, the new hill will exceed 240 m and cover 90 ha. With the upper slopes restored to heathland and the lower slopes used for agriculture, the new landscape will be comparable with other local high spots in the National Forest.
SLR is now moving ahead with the detailed design which will involve the translocation of species rich hedgerows, lichen covered rocks and lowland wet grassland as well as the creation of critical habitats for protected species such as amphibians, badgers and bats and the creation of a Biodiversity Action Plan for the whole estate.
“This project is a great example of how sensitive landscape design can help to overcome local concerns while also providing biodiversity enhancements,” said SLR Principal Sarah Planton. “Our scheme provides a complimentary balance between the impact of quarrying on the landscape and allaying the concerns of local people.”
Working closely with the in-house team SLR has provided landscape, restoration and ecological advice including population surveys of amphibians, reptiles, badgers, birds and lichens. Over 20 km of hedgerow were also
surveyed and a monitoring regime for important remnant grassland habits has been established.