Power management company Eaton says its Aeroquip X-FLEX very high pressure spiral hose “has been performing to expectations” and helping manufacturers servicing continuous miners operating in highly abrasive environments in South Africa to meet their contracted coal extraction rate terms by increasing uptime and decreasing maintenance and service times.
South Africa is one of the ten largest coal producers and the fourth largest coal exporting country in the world, with a significant proportion mined with continuous miners using the room and pillar technique. Downtime on these continuous miners could cost the mine up to $10,000/hr in lost production – a cost so high that some mines measure this downtime in minutes. There are many factors that can cause downtime, but Eaton argues that the majority of cases are due to hydraulic hose assembly failure.
“Eaton’s route to market for South Africa’s mining industry is through a distribution network for which we supply hydraulic assemblies, fittings and accessories,” explains Jorge De Lima, team lead sales for Southern Africa for Eaton’s Hydraulics business. “Many of these 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.”
The area on a continuous miner where most breakdowns occur is on shear cylinders that move the cutting bobbin. Upon daily servicing, 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. Eaton states: “In disciplined sites, the preferred hose used on these machines is Eaton’s GH506, which offers excellent 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 annual downtime caused by the failure of hydraulic hose assemblies was 9,000 minutes–this equates to approximately $1.5 million in lost production,” recounts De Lima. “Here, the servicing regime had gradually relaxed over time and the hose assembly was failing.”
While the supplier was contracted to ensure that the continuous miners met or exceeded the set rate per tonne of coal extracted, it couldn’t 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. X-FLEX features a rugged, abrasion resistant DURA-TUFF cover, which provides longer life in this abrasive environment compared with the original high pressure hose. In addition, it provides a 46% reduction in force-to-bend ratio, which made it easier for the supplier to handle in the shop, and less time consuming to fit on 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.
“On replacement of this original hose assembly with Eaton’s Aeroquip X-FLEX very high pressure spiral hose, duty time increased considerably and downtime for the mine was reduced by 2,000 minutes,” says De Lima. Squeezing lost production costs by $333,000, by simply replacing a hose, is very attractive for the mine and the supplier. With supply and service of these mine sites in the region of $50,000/mth, the mine has effectively saved and recovered its spend.