May 30 - Johnson Crane Hire has deployed eight large capacity cranes and 20 smaller models to complete a number of heavy lifting operations at a petrochemical plant in South Africa during its annual maintenance shutdown.

The small cranes ranged in capacity from 30 tonnes to 120 tonnes; while the eight larger cranes had capacities ranging from 180 tonnes to 600 tonnes.

"We started work on the project eight months prior to arriving on site. This involved intensive studies of the lifting programme, starting with site inspection through to undertaking compaction tests to ensure the load bearing capacity of hard stands and marking the positioning of all cranes on site," said Philip Bailey of Johnson Crane Hire.

The large cranes were used on site to replace ten large vessels, each weighing between 110 and 117 tonnes and measuring up to 12 m long. In order to lift the old units out of the plant, a 600-tonne capacity crawler crane was used, operating at a radius of 42 m.

Another heavy lift operation involved the removal of a unit known as a 'submarine', which was disassembled into three 8 m long sections, each weighing 21 tonnes. A 550-tonne capacity crane was equipped with a 21 m luffing jib and positioned at a 45 m radius for this particular lift. 

"This entire project called for detailed planning and attention to detail in all aspects of the work undertaken. All components had to be carefully removed, and new units accurately placed and aligned to avoid any damage to the plant," added Bailey.