Background Traditionally, quarry and road stone producers throughout Europe have used conventional asphalt plants to manufacture the majority of asphalt products. However, such plants have limitations: - They are designed to produce coated products in large quantities as required for commercial viability only; - The continuous nature of the process causes waste when product recipes are changed and makes such changes more difficult; - Plants are stationary and have a significant environmental footprint; - Plants also require large storage areas to maintain operational levels of feedstock; - Wastage problems occur because of operational difficulties in matching the various elements of the process; - Systems have high fuel consumptions, wasting both electricity and gas/oil through an inability to modulate burners and dryers and; - Plants have high maintenance costs. Batch-heater coating plants were historically designed for particular applications for a small sector of the British market. However, progressive development of production features, involving additional mechanical components and updated process control systems, means that these plants now offer a high degree of control for the production of coated roadstone. The advantages of batch heaters are that they are: - able to produce the product in variable quantities from 0.5 to 5.0 tonnes, on a batch- by-batch basis; - able to offer a range of 150 product mixes; - suitable for urban locations; - require a smaller storage area; and - leave a smaller environmental footprint. However, like large asphalt plants, batch-heater coating plants use large motors to operate conveyors, fans and burners to heat the aggregate to the required temperature. They use high levels of power and consume a considerable amount of fuel. This is further exacerbated by the difficulty involved in modulating the burners or fans when lower temperatures are required. Objectives The overall objective of the REF project was to produce the first environmentally friendly modular batch-heater plant, which could be disassembled, moved and reassembled with minimum cost and effort. Specific objectives were to: - build and demonstrate an innovative industrial process to produce asphalt-coated products; - demonstrate an innovative filtration system, reducing emissions to below 10mg/m³; - reduce the consumption of power (electricity) and fuel (gas/oil) of this industrial process by up to 75%; - increase the use of recycled materials within the process to 50%, reducing the level of virgin product required; and - significantly reduce noise levels of the process. Results The REF project has successfully redesigned every major aspect of batch heaters, making them portable, clean enough to use in urban environments and powerful enough to produce any required roadstone recipe. It could be considered a success story. The main quantitative results are: - up to 75% reduction in electricity consumption; - up to 30% reduction in gas and fuel oil consumption; - reduced particulate emissions to below 10mg/M3; - 50% increase in the level of recycled materials that can be used in the process; - a reduction in raw aggregate materials from the quarry when replaced by recycled materials; - reductions in landfill usage when recycled materials are utilised; - increased acceptable quality of commercial end products (asphalt etc.) with a range of 400 product mixes; - a reduction in the cost of and emissions from fuel in transporting end products to their point of use; - reduced visual impact by lower height of plant and; - a further reduction in environmental impact when plant is located adjacent to significant road works. It is worth noting that the maximum particulate output permitted for asphalt plants in the UK has recently been reduced from 100 mg/m3 to 50 mg/m3. As the REF plant was already demonstrating particulate output of This project has been awarded the title of "Best of the Best" from a shortlist of 22 "Best" LIFE Environment projects in 2006-2007