In 2008, MARINI made a high-profile return to the British market by attracting a top-ranking client: CEMEX. This Mexican cement manufacturer - one of the world leaders in its field - has recently diversified, especially in the United Kingdom, where it has taken over several road building firms. To support its growth strategy, CEMEX has purchased the latest addition to the FAYAT Group's line of batch-mix asphalt plants - the TOP TOWER 3000 - for its Shap site in Cumbria.
Behind the scenes on the project
This commercial success is closely linked to the new organisational structure that has been established for the United Kingdom in conjunction with the Scottish company CORMAC Ltd. A novel aspect of this partnership is that in addition to acting as an agent, CORMAC also manufactures some of the plant's components locally, such as the aggregate feed bins and the binder storage tanks, in addition to carrying out all of the electrical wiring, assembly and commissioning operations, and bringing the equipment into line with the stringent local regulations.
Regulatory requirements in the United Kingdom
Electrical cables must be armoured, i.e. clad in an additional metal sheath designed to reduce the risk of accidental damage. They must also be fitted with special brass ends. These requirements significantly increase the cabling time, primarily because of the increased stiffness of the cables.
Employee safety regulations are also very stringent:
- All technicians working on site must hold a range of qualifications and permits relating to their specialist fields.
- Every day, a risk assessment covering the work to be carried out must be submitted to the Health & Safety Manager who is always present on site.
- As British safety standards sometimes exceed the rules imposed by the European Machinery Directive, special safety guards are also required (see photo).
Adapting the plant to local requirements
CEMEX has opted for a TOP TOWER 3000 with 70 m3 of offset storage, mounted on weighing scales, for real-time monitoring of hot-mix asphalt availability. The plant is equipped with a recycling ring and a pneumatic system is used to add fibres to the mixer. CEMEX was particularly impressed by the following results:
- Energy performance and savings due to the short gas circuit - a direct benefit of the filter being positioned above the dryer drum.
- Versatility, due to the plant's ability to produce all modern special and low-energy asphalt formulas.
- Adaptability, thanks to the TOP TOWER's ability to incorporate alternative recycling solutions, such as the direct addition of RAP to the mixer.
Nevertheless, local standards governing hot mix formulations have required modifications to the plant. Thus, whereas the TOP TOWER's conventional fines recycling circuit has the fines weighing hopper fed directly by the under-filter hopper, CEMEX wanted all of the recovered fines to be stored in a dedicated vertical silo that would allow the recovered fines to be either removed or added back into the final mix.
Initial results
So far, due to the postponement of the large scale projects that had initially been planned, only 25,000 tonnes of asphalt have been produced since the plant was commissioned in September 2008. Nevertheless, several tests have already been performed at full output and the contractual commitment to provide a production rate of 160 T/h at 5% water content has easily been satisfied. These conclusive results allow CEMEX to contemplate the future night-time motorway projects for which it is bidding with confidence.
