Skip hoist wire rope — inspection, lubrication and when to discard
Symptom
Broken wires, reduced or locally swollen diameter, corrosion, kinks or birdcaging, fast rope wear, bad spooling on the drum, or slack rope on descent.
Likely causes
- Normal end of life from bending over sheaves and wear.
- Sheave groove too small (broken wires in two parallel lines) or a seized sheave.
- No lubrication in dusty, wet conditions, causing inner corrosion.
- Rope rubbing the structure, or wrong fleet angle at the drum.
- Skip stuck on the rails while the winch unwinds.
Most likely and cheapest to check first.
Checks
- Daily, watch the visible rope and listen at the sheaves from a safe place.
- Locked out with the skip secured, inspect the full length, especially over sheaves, on the drum and at terminations.
- Measure the diameter with a caliper at several points, turning it to find the largest reading, and record it.
- Count broken wires over a set length; test the slack-rope switch monthly.
Fix
- Discard the rope at a 10 % loss of nominal diameter, or at the broken-wire limit, kinks, birdcaging or heat damage.
- On double-rope skips, replace both ropes together.
- Free or replace seized sheaves; correct groove size.
- Lubricate with the rope maker's lubricant; keep the minimum turns on the drum.
Stop the equipment if
Kinks, birdcaging, strand protrusion, heat damage, or a slack-rope switch that does not stop the winch.
Parts you may need
A broken rope drops the skip
A broken rope sends the skip and its load down the track. On a plant without an anti-fall device, nothing else stops it. Rope delivery can take weeks, so keep a complete set with terminations on site.
DANGERNever stand under the track or in the pit while the skip can move. Never bypass a slack-rope or over-run switch.
⚠ Every check inside a machine starts with full lockout. Safety disclaimer