An extensive reference base of successful heavy lifts, an experienced design, rigging and operational crew, a cost effective 50 ton 38m radius capability, and the ability to mobilise quickly and efficiently were all deciding factors in the award of a heavy lifting contract to Johnson Crane Hire. The company started work on the removal and replacement of a number of components on Debmarine Namibia’s !Gariep offshore diamond mining vessel.
Although Johnson Crane Hire has supplied a number of smaller cranes to various De Beers Marine projects in the past, this is the first time that the company has performed a heavy lift for the organisation. Cornelis Grotius, general manager of the Johnson Crane Hire Heavy Lift Division, explains that the company is able to leverage its extensive experience with a wide spectrum of clients across the petrochemical, civil engineering and construction, power, mining and heavy manufacturing sectors.
“Working conditions on a marine vessel heavy lift could be compared to the congested conditions and space constraints experienced on petrochemical contracts. The emphasis on safe operating conditions, while always a priority for Johnson Crane Hire, is magnified in such environments. Careful planning, reliable equipment and a well trained and experienced operational team are critical factors in the success of these projects,” Grotius points out.
The !Gariep was acquired by De Beers in 1998, redesigned, re-equipped and then deployed to the Atlantic 1 mining concession area near the mouth of the Orange River, off the Namibian shoreline. The vessel is now owned, operated and managed by Debmarine Namibia and is registered at the Namibian Port of Lüderitz. The vessel houses 50 people, has a gross tonnage of 8,471, a deadweight of 5,939 tons and measures 118.969m long by 24.56m wide. Scheduled maintenance and upgrading of the Debmarine Namibia vessels is undertaken every three years, when the vessels berth at the dry dock in Cape Town.
The scope of work for the project comprised removal and installation, in this specific order, of the 24 ton crown, the 45 ton lifting guide beam complete assembly, the 42 ton compensating guide beam complete assembly, including spout and upper universal; the 42 ton stabiliser guide beam, including the lower universal, power swivel, water rotor and elevator; the 22 ton gimbal; two 50 ton drill bits; and various mining system equipment.
Eugene Lamont, De Beers Marine senior mechanical engineering officer, explains that plant and equipment upgrades are instituted to improve the performance of the vessel and require extensive forward planning. “Once the !Gariep is placed in the dry dock, it is critical that all repairs and upgrades are expedited quickly, to allow the vessel to return to base as rapidly as possible. We have already started planning the next round of upgrades for 2018.”
Johnson Crane Hire selected its Liebherr 750 ton all terrain hydraulic crane for the !Gariep contract, due to the sheer size and weight of the components to be lifted. The crane was deployed from Johannesburg under its own power and the counterweight and 28 metre luffing jib were transported separately on low bed trucks. Travelling time was two days and set up on the quayside at the Sturrock Dry Dock in Cape Town harbour took three days. “We were cognisant at all times of the tight contract period so the team quickly sprang into action to ensure that deadlines were adhered to. The sometimes excessive winds in the harbour area were an aggravating factor but, due to careful planning and our ability to work in challenging environmental conditions, we were able to abide by the project schedule without incident. Working between 10 to 12 hours each day, the team successfully completed the project within the revised forecasted period of 55 days,” says Grotius.
Grotius says that conditions at the Sturrock Dry Dock were extremely congested, with several marine contractors vying for space to work on the !Gariep at one time. “Proper planning of the lifts and open communication lines with the client and other contractors was paramount to the success of the project. It was incumbent on the Johnson Crane Hire team to remain adaptable and adept at all times.”
Lamont says that De Beers Marine is very pleased with the professional and flexible attitude that Johnson Crane Hire exhibited in the original planning stages and in the face of the rigorous schedule and unplanned scope changes. “The team exhibited a safety focused attitude towards the lifts and successfully expedited the heavy lifts with expertise and aplomb.” “Every contract in which Johnson Crane Hire is involved is an opportunity to gain experience and improve our skills in our striving towards service excellence. The !Gariep contract provided us with additional expertise which we will be able to transfer to future projects in the marine and other industry sectors,” Grotius concludes.