At Aalborg Portland, chalk has been dug in an almost rectangular pit next to the factory for 30 years, and due to the extent of the chalk deposit, the digging direction had to be changed to follow a circle.

 

Chalk is the most important component in cement, and the supply is continuous directly from the chalk pit. The extraction takes place using an excavator that weighs 1,256 tonnes and digs to a depth of 40 m, of which 38 are below the water surface.

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The task

Adding was in charge of planning and managing the assembly and commissioning of the new equipment, which had to be completed in just three weeks from dismantling the old equipment to commissioning the new. Everything was planned down to the last detail in collaboration with the various suppliers with a focus on doing as much work as possible before shutdown. When the replacement of a 1,400 m long high-voltage cable (10 kV) was included, there were also a number of safety considerations.

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Implementation

A major gain was achieved when the critical path through the project plan was analysed, which led to a number of changes so that there could be more parallel activities by different suppliers. During the installation, there was daily supervision of 12-14 hours with the solution of the technical challenges that arose, daily coordination with the parties involved and a strict follow-up to the schedule. A task list was also followed up on a daily basis to assist the contractors in optimizing their efforts. A significant challenge was the weather situation with snow and hard frost, which made both assembly and moving in difficult. Another was the delay of components delivered from a Polish steel supplier, as well as minor design changes during the process.

 

The result

 

• The equipment was commissioned on time and delivered chalk to the kilns immediately after start-up

• There were no workplace accidents, despite handling heavy components and a tight schedule