Power management company Eaton’s Aeroquip X-Flex high-pressure spiral hose has been meeting performance expectations, helping manufacturers that service continuous miners in South Africa – which operate in highly abrasive environments – to meet their contracted coal-extraction rate by increasing uptime and decreasing maintenance and service times.

Downtime on continuous miners could cost a mine up to $10 000/h in lost production – a cost so high that some mines measure this downtime in minutes.
Eaton notes that, while there are several factors that can cause downtime, most cases of downtime are due to the failure of hydraulic hose assemblies.

“Eaton’s route to market for South Africa’s mining industry is through a distribution network, through which we supply hydraulic assemblies, fittings and accessories,” explains Eaton’s hydraulics business team lead sales manager for Southern Africa Jorge de Lima.

“Many of these [distribution] companies are contracted by the mine to ensure that the continuous miners meet or exceed a certain rate per tonne of coal extracted, which is why avoiding downtime is of the utmost importance,” says De Lima.

Shear cylinders that move the cutting bobbin are the root of most breakdowns on a continuous miner. When the unit is serviced daily, these areas are cleared of coal debris and the assembly is checked for any cuts, signs of abrasion or visible leaks from the threaded connection.

At disciplined sites, the preferred hose used on these machines is Eaton’s GH506, which offers enhanced performance when cleaned and serviced regularly. The hose-end fitting features a special wire trap design that requires the hose to be both externally and internally skived to help ensure hose and fitting integrity under impulse conditions.

“At one particular mine site, which operated several continuous miners, the total [yearly] downtime caused by the failure of hydraulic hose assemblies was 9 000 minutes, which equated to about $1.5-million in lost production,” says De Lima, adding that the servicing regime had gradually relaxed over time and that the hose assembly had been failing.

While the supplier was contracted to ensure that the continuous miners met or exceeded the set rate per tonne of coal extracted, it could not influence the rigour of the daily service regime.

To overcome this challenge, the supplier replaced the original GH506 hose assembly with Eaton’s higher-specification Aeroquip X-Flex hose.

The X-Flex hose features a rugged, abrasion-resistant Dura-Tuff cover, which provides longer life in South Africa’s abrasive mining environment, compared with the original high-pressure hose. In addition, it provides a 46% reduction in force-to-bend ratio, which makes it easier for the supplier to handle in the shop and less time-consuming to fit onto the equipment.

When used in conjunction with one-piece Aeroquip global spiral TTC crimp fittings, the X-Flex hose assembly is also easier to build, since skiving is not required.

De Lima notes that, when Eaton replaced the mine’s original hose assembly with the Aeroquip X-Flex high-pressure spiral hose, duty time increased considerably and downtime for the mine was reduced by 2 000 minutes.

He adds that the mine has effectively saved and recovered its spend, having cut lost-production costs by $333 000 with the simple replacement of a hose.