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Refurbished winders attractive alternative

12th December 2014

By: Mariaan Webb

Creamer Media Senior Deputy Editor Online

  

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Refurbishing existing mine winders remains a popular practice in the mining industry, with DRA’s specialist consultant winder systems team reporting that the majority of its clients choose refurbished equipment where possible, owing to significant cost and time savings.

DRA director responsible for the winder systems business, Graham du Plessis, explains that mining companies can realise savings of between 30% and 50% on the capital cost of equipment by going the refurbished, second-hand winder route. Delivery times, which for new winders are typically in the 24-to-30-month range, are also halved.

Capital and delivery savings often make refurbished second-hand equipment a “no-brainer” for the end-user, he says in an interview with Mining Weekly.

In the last 15 years, about 65% to 70% of the winder projects DRA was involved in, have been refurbished machines.

“Old winders never die. We simply refurbish them and reuse them,” quips Du Plessis, citing the example of the oldest continuously operating winder in South Africa at the East Rand Property Mines, in Boksburg, Gauteng. The winder was in use at its original location for 94 years until the mine was closed and the winder taken out of service and scrapped in 2008.

“That’s indicative of the kind of lifetime a winder can deliver service for.”

The mechanical portion of the winder, such as drums, drum shafts and other heavy equipment, hardly wears out unless the winder was subjected to duties beyond which it was designed for, although certain wearing components are replaced in the course of refurbishing or upgrading.

New equipment is usually needed on the electrical side, particularly the electronic equipment, which has an obsolescent life of about 15 years. “When we refurbish a winder, we provide state-of-the-art electronic control equipment and new winder drive equipment.”

The hydraulics on brake control systems are also usually upgraded with modern components.

DRA’s winding systems unit has a number of firsts under its belt, including, at the time, commissioning the largest Blair Multi-Rope (BMR) winder outside South Africa, the largest Koepe winder on the African continent and supplying South Africa’s first ground-mounted Koepe winders.

Installed at a large copper mine in Zambia, the refurbished second-hand BMR-type winder has an 8.25 MW drive and is one of the biggest north of the Limpopo. The Koepe friction winder, on a platinum mine near Rustenburg, in the North West province, boasts an 8 MW drive and a drum with a 7 m diameter.

Du Plessis explains that the BMR winder performed the kibble duty, while the shaft was being sunk. It was later converted for use as one of the two permanent rock winders on the shaft.

At a large South African platinum mine expansion project, which involved the sinking of three shafts, DRA used a combination of refurbished second-hand machines and new ones. Du Plessis says this project is the first in South Africa to use ground-mounted Koepe winders.

A unique application of this expertise is to use these machines as single-drum winders during the sinking of the main shaft. Once the sinking is completed, they will be converted to their permanent duty as friction-type Koepe winders.

“There has been tremendous cost and time savings to the project in doing that,” Du Plessis says of the ten-year project, which is due to come on line in mid-2016.

Deep Roots
DRA established its winding capabilities in early 1999, after most of the mining head offices in South Africa were closed, essentially leading to the demise of the country’s unique winder engineering departments.

DRA founder Brian Dowding recognised the continued need for specialist winder engineers in South Africa and approached Du Plessis and his brother Mike du Plessis to establish DRA’s winding division. With time, the size of the department was increased by bringing in other experienced winder engineers, as well as new and younger inexperienced mechanical and electronic engineers, who have been trained up to become winder specialists. At one time, the division had grown to 21 employees. Today, DRA Winding Systems has a team of highly specialised mechanical, electrical, electronic and software engineers who continue to provide the service to the mining industry.

“There are very few winder specialist people around the world. We have by far the majority,” Du Plessis says.

The DRA winding division preserved the specialist skills developed in South Africa to cater for the country’s unique deep-level mining needs and continues to provide design, technical, consulting and project management services to the local industry. In recent years, the winder department has spread its wings further north and overseas.

Currently, it has a number of contracts in South Africa, Zambia, Tanzania, Ghana and the Democratic Republic of Congo and has operated previously in Mali and Australia.

Winder Training
To expand the winder skills pool, DRA is providing training courses to engineers and winder maintenance staff. It is mostly junior engineers and engineers in training, who are required to qualify as candidates for the government certificate of competency, who attend these classes and “hands-on” training.

The courses take the form of classroom lectures and on-site practical training. The 17-day classroom course accommodates groups of up 16 people. The practical training is an intensive, hands-on course and accommodates two people at a time.

Edited by Creamer Media Reporter

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