Mine hoist gear couplings: The gift that keeps on giving

In this case study, CBC ups the ante on solutions service by providing a mine hoist coupling solution to a large mining company in New South Wales on practically record notice.

CBC product manager for mechanical drive systems and belt drives, Steve Hittmann, took the lead on delivering an expedited solution, reducing an expected lead time of 28 weeks to just a few days, and cutting the product cost in half.

A couple of days before Christmas, CBC was approached by a customer who had experienced a sudden breakdown on their mine winder, the hoisting application they were running underground.

“The mine winder is usually located in a shed nearby the recognisable scaffolded tower operation that runs the cables,” Hittmann says. “This is definitely a critical component for an underground mining operation, as without it the capacity for carrying materials up and down from the underground operation is reduced to zero.”

The coupling in question was driving the gearbox and wheel component, winding support cables through the winch and pulley arrangement in the tower.

With the wheel of the mining hoist out of action, and a replacement up to six months out, the customer was facing the possibility of extended downtime on operations, or worse, a full halt to production.

Hittmann put a call out for ex-stock in house at CBC and located a Rexnord gear coupling solution that was available to be shipped out to the customer’s site on a few days’ notice.

“Christmas came early for the customer in this instance, and it was a win on all sides,” Hittmann says.

“Not only did we have the stock on hand, but this particular coupling had a much stronger torque and higher bore capacity, and its small construction weighed about half as much as the original coupling did.”

The result was a gear coupling solution that had a much larger capacity than its predecessor, while taking up much less area, weighing less, and offered at half the price. Furthermore, it was delivered immediately to the customer’s doorstep.

“We were able to save on the production costs of having it made overseas, the shipping costs and logistics,” Hittmann says.

“We had it up and running a week after Christmas, just in time for the new year.”

When analysing these types of applications, Hittmann says the most important factors to consider are the power and the speed requirements.

“Power and speed are how we determine the amount of torque,” he explains. “The advantage of the Rexnord gear coupling solution we provided is that it accommodates high torque on low-speed heavy duty applications.”

“Examples of these type of applications on a mine site are ball mills, belt conveyors, bucket elevators, apron feeders, hammer mills, mixers, pug mills, pumps, screens, winches, agitators, and compressors.

“Because there is a lot of rough and tumble moving heavy materials on a mine site, many of the applications operate on lower speeds but require high torsional capabilities.”

When asked about tips and tricks about installation and maintenance of Rexnord gear couplings, Hittmann recommends using an induction heater on installation to cause the coupling to thermally expand for determining the right fit. He also suggests applying the Rexnord Falk Long Term Grease (LTG) to eliminate the need for lubrication intervals and ultimately extend the life of the gear coupling. 

LTG — Quick Facts:

  • Rexnord Falk engineers have spent years measuring the wear rates on coupling components using various lubricants and coatings.
  • The results of extensive research indicated that greases with high viscosities and low bleed rates produce the longest life.
  • Falk LTG is specially formulated to provide superior lubrication for flexible shaft couplings.
  • The consistency of Falk LTG changes with operating conditions. Service conditions cause the lubricant to become semifluid, while the grease near the seals will set to a heavier grade, helping to prevent leakage.
  • LTG is highly resistant to separation. This resistance to separation allows the lubricant to be used for relatively long periods of time.
  • LTG has the United States Department of Agriculture Food Safety & Inspection Service (USDA) approval for applications where there is no possibility of contact with edible products (H-2 rating).

Benefits on an Application

  • Increased coupling life.
  • Significantly extended re-lubrication intervals.
  • Reduced maintenance costs.
  • Reduced downtime.
  • Superior lubrication.
  • High load carrying capabilities.
  • Usable up to 121°C.

To keep up to date with Australian Mining, subscribe to our free email newsletters delivered straight to your inbox. Click here.