Free and easy

Bulk handling, long associated with grab-equipped luffing jib cranes, was given a much needed kick up the backside with the advent of the mobile harbour crane. Flexibility has been even further enhanced through the introduction of hydraulic material handlers, while specialist agribulk companies continue to favour mobile shiploaders.

The Scottish Ports division of Forth Ports took an interesting decision in 2008: it acquired four Sennebogen 870M material handlers in response to a need to decommission life-expired fixed-rail equipment.

Business development manager, Nik Scott-Gray explains that a study the company had undertaken at its seven Scottish ports over a period of 18 months had determined that 80% of its general cargo business was carried by vessels of 6,000 dwt or smaller.

“It became evident that there was no point in buying massive cranes when other options were available, especially when utilisation of the fixed units over the past five to ten years hadn’t been that great,” recalls Mr Scott-Gray.

With the exception of Leith, where three specialist cranes handle around 1.5m tonnes of coal per annum, the majority of other bulks being handled by the company’s Scottish ports consists of agribulk, timber and pulp, for which a hydraulic material handler was deemed more than adequate.

According to Mr Scott-Gray, Forth Ports looked at five possible suppliers, before eventually choosing Sennebogen.

Asked what factors influenced the initial purchase, he says that the company looked at a wide range of things, including whole life cost, encompassing such elements as reliability, productivity, ease of maintenance, ability to work with quay loadings, and flexibility in terms of health and safety. The ability to transport the cranes easily by road was also a significant factor.

Given that the company’s ports are at a maximum travelling distance of no more than 2½ hours, it was decided to acquire the units centrally and move these between facilities as and when required. Even so, one will invariably be found at Leith, Dundee, Rosyth and Grangemouth, although an average of seven movements between ports are made each month. Operators are centrally contracted, with maintenance also managed by a dedicated team, albeit with external support.

“Cycle times of 50 seconds means that the Sennebogens are highly suitable for bulk handling, particularly agribulk, which is a speciality of both Dundee and Leith. We can achieve loading rates of 420 tons per hour with one handler, effectively the work of two cranes. In addition, we no longer need hoppers, which in itself is a big saving,” says Mr Scott-Gray. “For the type of business we run, we have found the Sennebogens to be exceptional.”

He explains that the material handlers can also shift easily between quays, which means bulk vessels are no longer limited to those quays equipped with rail-mounted equipment. So any free quay can be used, or that closest to the most suitable storage area.

Asked whether any high profile accidents have occurred when manoeuvring the units around the various ports, he says that, being on wheels, rather than tracks or rails, means that driving is relatively simple and takes place at quite slow speeds, hence risk of collision is minimal. A specialist contractor moves units between ports using a low-loader, with the boom tucking underneath the main body of the unit. Loading requires little more than an hour.

Nevertheless, being hydraulic, he does concede that the Sennebogens are somewhat more complicated than a two-rope grab crane, which he describes as “a pretty basic machine”. While the hydraulics can be very sophisticated, after 18 months of operations, Forth Ports reports no major problems.

UK-based Gleadell Agriculture Ltd, meanwhile, is in the process of acquiring its third mobile shiploader. Managing director, David Sheppard, says that shiploaders have proved both cost effective and reliable, while handling and environmental performance easily matches that which can be achieved with far more expensive fixed installations.

Port Strategy asked David Sheppard to give an insight into his company’s thinking when it purchases new equipment. Is it the initial cost of the machine that determines the acquisition, or does Gleadell take into account whole life costs?

“The prudent thing to do is to look beyond the initial cost and consider what the whole life costs will be. However, in our experience, mobile shiploaders have proved themselves to be cost effective in both the short and long term,” he says.

Gleadell handles wheat, barley, pulses and oilseed rape, commodities for which mobile shiploaders are extremely suitable. Productivity, notes Mr Sheppard, is certainly equal to that available when using fixed equipment. For this reason, Gleadell’s new venture at the UK east coast port of Great Yarmouth will once again feature a mobile loader, which is to be supplied by B&W in May 2010.

“We decided to buy from B&W yet again given that productivity levels achieved with that company’s equipment at our existing Immingham operation, which began in 2002, have been extremely good. This is because B&W’s mobility and receiving concepts enable us to discharge up to four wagons simultaneously. There, we have hit peak handling rates of 2,000 tons per hour, while even average rates of 1,200 tons per hour are being achieved. At Great Yarmouth, we are aiming to handle 1,000 tons per hour when the ship loader is working at full capacity,” says Mr Sheppard, noting that this is more than adequate for the handysize ships that will call there.

Environmental considerations are also very important to Gleadell, so dust control systems will be fitted to both Samson feeders and at transfer points. In addition, a Cleveland Cascade telescopic chute at the loading boom end will eliminate dust and help to protect the product from degradation. A permanent magnet and mesh grills fitted will also help to remove unwanted tramp and metals, thereby helping to ensure product integrity.

Asked whether the in-built mobility of a shiploader might result in damage during repositioning manoeuvres, Mr Sheppard says that, in 30 years of operating mobile equipment, Gleadell had experienced no major incidents of this type. He puts this down to the robust nature of the B&W units, as well as the easy-to-control movement systems that enable complete machines, weighing up to 450 tonnes, to be precisely located in even quite restricted quay areas.

Part of the reason for the enviable safety record is down to the operator training that is given by manufacturer B&W Mechanical Handling Ltd. This, says Mr Sheppard, is comprehensive, with the operators proficient within days.

Andrew Mitchell, B&W managing director, notes that it requires just one person to move a complete machine. No other equipment is required, since everything is controlled from a conveniently located operator cabin.

“When considering the relocation of one of our shiploaders between terminals, an operator has to take into account both distance and access. However, I would stress that these are not the size and type of machine you can drive along the road, because they are far too big and heavy.”

Mr Mitchell claims that an operator can keep a B&W shiploader in front line service for 20-30 years, depending upon application and duties performed. Compared to similar fixed installations, mobile loaders are little different in this respect.