Maximizing Shovel Rope Life

Every WireCo WorldGroup wire rope has been designed to offer efficient, dependable service to overcome the rugged conditions of surface mining. But no wire rope will last forever. We've developed the following tips to make the most of your shovel ropes' service life.

• Reduce downtime during changeover.  To install new ropes in less time and with less expense, many mines order their ropes "hairpin wound." This leaves both ends of the rope on the top of the reel so they can be pulled back to the drum at the same time. However, if the two ends are not removed from the reel in the proper order, the result will be rope wrapped around the drum of the shipping reel. This will cause an unnecessary increase in installation time.  To solve this potential problem with hairpin-wound ropes, we link them with seizing strand. For proper unreeling, do not remove the seizing strand until you've pulled both ends of the rope from the reel. If you need further help with this procedure, WireCo WorldGroup can provide assistance.  Drum ferrules or buttons are also available. Simply specify the ferrule size and tolerance when you order.
• Minimize dampening on drums.  When a slack rope is quickly tensioned, there's a vibration created in the rope. This vibration is dampened where the rope contacts the sheaves or drum, which can lead to rope fatigue.  To help minimize the vibration on the rope when the bucket starts its digging cycle, we recommend improving digging techniques to reduce sudden load on ropes. These include starting the cut slowly and smoothly, then loading the rope gradually while reducing slack on the rope. Do not "cowboy" the ropes, in other words.
• Examine for uneven wear on twin sheaves.  If one groove wears deeper than the other of a twin sheave, the rope is forced to slide because of the difference in sheave groove circumference. Frequently when this happens beyond the hardened surface of the sheave, you'll notice a rapid change in the sheave, causing more serious problems later. The result is a decrease in rope performance and service life as well as accelerated sheave wear.  To help prevent this problem, always make sure both grooves of twin sheaves are the same depth. If they aren't, replace or repair the sheave. Refer to the shovel manufacturer's instructions for tolerances on groove depth wear.

Maximize Dragline Rope Life

To help you get the most service life from your WireCo WorldGroup hoist and drag ropes at the lowest cost, we've developed the following recommendations for use with your draglines:

Recycle used ropes.  If hoist and drag ropes are the same diameter you can extend the service life of selected ropes through recycling. Take your used hoist ropes -- making sure they pass your inspection – cut them to the proper length and install them as drag ropes for your machine. You can also use old drag or hoist ropes for dump ropes if they're the right size and still have useful service life. When's the best time for that? Your experience is your best guide.

Resocket drag ropes regularly.  Drag ropes tend to show the heaviest wear at two different locations. Look for broken wires at the base of the wedge socket, where dampening vibration can lead to fatigue. Or watch for a section of localized wear directly in front of the fairleads.  Either way, you should resocket at approximately every 20 percent of the rope's expected service life until the rope either becomes too short to use, wears out or until you decide to replace it. Simply cut the rope at the wedge socket and make a new end attachment. This way, you're moving a new rope section into the biggest wear area and extending the service life of your overall rope.

Switch dragline ropes end for end.  Drag rope wear normally occurs in the area that operates through the fairleads. This may affect about one-third to one-half of the rope's overall length. We recommend that when your rope reaches approximately 30 to 40 percent of its service life, you should switch ends of the rope. In other words, place the bucket end on the drum, and vice versa. By switching one end that shows significant wear for the other end, you're helping to distribute the wear pattern along the rope, thus allowing you to get maximum rope service.

Check for proper fairlead operation.  To help assure maximum service from your straight-through or reverse-bend fairlead systems, you need to check these critical areas:

•  Groove contour. Grooves that are too small or tight can cause pinching and increased wear while grooves that are too wide can cause flattening of the rope -- both of which can reduce your rope's life.
• Proper sheave alignment. Fairlead systems have three different kinds of alignment: between the vertical and horizontal, between vertical and the bucket, and the alignment of the sheaves themselves -- vertical to vertical, or horizontal to horizontal. The grooves of each of these fairleads can wear down over time as a result of continual rope contact, leading to reduced rope service life.  You can help maximize rope service life by aligning the sheaves properly with the bucket. The small space between the sheaves, however, may cause the rope to jump back and forth, so you need to be aware of possible impact fatigue or martensite and take steps to prevent them. One way is to shim up the sheave to restore proper alignment. It's best to check with your equipment manufacturer for proper alignment procedures.
• Sheave movement. All sheaves should rotate freely. Make sure that sheave housings that are required to pivot can move freely.
• Roller operation. Guide rollers in front of vertical sheaves should move freely to maximize rope life. If rollers become grooved or flat on one side, they should be replaced.
• Overspinning. A proven remedy is to put a heavy, tacky lubricant in the throat of the vertical fairleads. This helps the rope start and stop the sheave, and keeps the sheave from grinding against the rope. To reduce rope damage, do not begin the digging cycle until the vertical fairleads stop spinning.

 

Monitor drag troughs.  Covering the area between the fairleads and the drag drums, the drag trough frequently has sheaves, idlers and other members to support the drag rope when it is slack and protect it from possible damage.

If sheaves are used, the grooves in drag trough sheaves are affected by extended wire rope usage. Ropes will cut the groove smaller and deeper over time, causing accelerated wear and shorter service life from future ropes you install. Check with your equipment manufacturer for guidelines on sheave replacements.  If other materials are used to support the drag rope, make sure they're in proper repair.

Examine for uneven wear on twin sheaves.  The depth of both grooves of twin sheaves should always be equal. If one wears deeper than the other, the rope is forced to slide. If this wear extends beyond the hardened surface of the sheave, you'll frequently see a rapid change in the sheave, causing more serious problems later. This results in decreased rope performance and service life as well as accelerated sheave wear.

 You can prevent this problem by making sure both grooves of twin sheaves are the same depth. If not, always replace or repair the sheave. Refer to the dragline manufacturer's instructions for tolerances on groove depth wear.