Openpit mining and underground solutions provider Tenova Takraf is currently supporting four continuous ship unloaders (CSUs) under two service contracts awarded to the company in April last year by Italian power generation company Enel SPA.

Each contract services two bucket-chain CSUs previously supplied by Tenova Takraf Italy, located at Civitavecchia, near Rome, and, Brindisi, in the south of Italy, respectively to feed coal to two of Italy’s largest power plants.

Both support contacts are 24-month duration extensions of previous contracts, flowing from maintenance support originally supplied by the company to the two CSUs at Civitavecchia. The original support was mainly geared towards maintaining the reliability and reaching the planned annual output of 4.5-million tons a year at the coal terminal.

This has been consistently achieved at Civitavecchia, where the CSUs are the only source of input coal. At Brindisi, the CSUs handle coal in conjunction with grab unloaders.

Tenova Takraf Italy MD Alberto Dardano asserts that all four CSUs have achieved excellent performance since installation.

He adds that Enel recognises the importance of detailed and planned maintenance in consistently achieving optimum performance from their machines, which are of strategic importance in maintaining coal feed to the power plants.

Dardano notes that these service contracts are an expression of Tenova Takraf’s enduring relationships with its clients.

“In Enel’s case, the relationship dates back to the 1980s when Tenova Takraf Italy was then known as Italimpianti.”

Dardano highlights that Tenova Takraf’s aftermarket services are a crucial element in its total service delivery, as support to the client does not simply cease at project handover. “We believe in building long-term client relationships through living with and supporting our products over their complete life cycle.”

Machine Specifications
The CSUs at the Civitavecchia project have an operating capacity of 1.5-million tons an hour, while those at Brindisi have a capacity of 1.8-million tons an hour. The CSUs have the ability to download vessels of up to 130 000 t of dead weight.

The machines are equipped with a 38-m-high bucket-chain elevator and a slewing/lifting boom, which includes the transfer conveyor of 42 m in length.

One of the major advantages of these CSUs is their low environmental impact, as the power plants are under special control and supervision of the Italian government to upgrade system equipment to reduce all emissions. The CSUs minimise dust and noise emissions during the discharge cycle.

Tenova Takraf Italy developed the bucket chain continuous ship unloader in the 1980s and, since then, with ongoing enhancement to the technology, has supplied 15 machines worldwide.

The most sophisticated part of the machines is the articulated-type digging foot for which Tenova Takraf Italy owns the patent. Through the coordinated movement of dedicated hydraulic cylinders, the digging foot can modify its geometrical configuration to obtain the best bucket filling and reach the walls to remove the material residual.

Repeat Order for Apron Feeder
Meanwhile, in May last year, Tenova Takraf Africa successfully completed the supply of an underground apron feeder to the Wessels mine, which forms a part of BHP Billiton’s Hotazel manganese mines, in the Northern Cape.

The contract for the Tenova Takraf apron feeder was placed in September 2013, with commissioning completed in May 2014. The contract scope covered the design, manufacture, delivery to site and assistance. with installation and commissioning of the 1.25-m-wide by 6-m-long D4 apron feeder.

The 500 t/h feeder receives manganese ore of 500 mm maximum lump size to feed to a jaw crusher.

This was the second Tenova Takraf apron feeder to be ordered by Wessels mine within the past three years, with a 1.25 m × 15 m D4 apron feeder delivered in July 2012.

The apron feeder was supplied as a routine replacement of an existing one, also supplied by Tenova Takraf, which has been operating successfully at the mine since the 1990s.

The new apron feeder features a number of enhancements over the older design, including the use of standard undercarriage parts, which means that spares are readily available and more cost effective.

A design challenge was to ensure that the size and mass of the apron feeder assemblies were such that they could be easily transported underground through an incline.

This was achieved by splitting the frame in two longitudinal sections without the need to remove the flights or any other parts.

Tenova Takraf apron feeders are designed for demanding materials handling work in mineral, ore, coal and aggregate mining, as well as processing operations, combining robust, heavy-duty frames and rugged short pitch flights to provide extremely long service life.

They can be installed below any bulk solids storage or transfer facility of any capacity, with the feeder slope downwards, horizontal or upwards.