Checklist of potential control limitations
Checklist of potential control limitations Winder Machinery
Control Potential Limitations
Overwind/underwind protection
may need to be disconnected when long loads are raised – special precautions not taken
disconnected units not reconnected units damaged and not repaired
Thruster brakes limited effectiveness in emergency situations Three turn warning
alarm
difficult to hear over background noise
Lock bell system bank bell and shaft bells on one electrical circuit system not interlocked with brakes
unauthorised use of lock bell key
multiple lock bell keys used in single shaft
adoption of informal/abbreviated signalling systems eg.
“Open bells” to avoid repeated locking of winder brakes
“Short bells” to expedite shaft operations
onsetters and banksmen not trained in correct signalling code
Slack rope detection ineffective on incline shafts due to low rope tensions, especially when conveyances are moved onto the stations
Brake inspections and tests
not carried out on a routine basis
results not formally logged in appropriate record book ammeters giving reading of motor current for brake test purposes not visible to driver
failure to define and communicate critical values of motor current to driver and engineering staff
staff not familiar with correct brake testing procedures electrical interlocks need to be bridged to test emergency brakes
Checklist of potential control limitations (contd) Ropes
Control Potential Limitations
Shaft rollers not located or aligned for optimum effectiveness rollers jammed/stuck
damaged by use of incorrect material cars damaged rollers not identified and repaired removed and not replaced
Rope inspection and testing
shortage of competent/qualified staff
regular front end cut and testing not undertaken rope inspection records not maintained
Control of brake application
slow braking mode characteristics not defined and set different braking rates not applied when raising and lowering conveyances
Load control maximum loads and number of materials cars that can be transported at one time not defined and
communicated
lack of competent/qualified staff to supervise movement of heavy/awkward loads
Physical barriers etc.
Control Potential Limitations
Safety drop rails and safety drop sets
do not make contact with footwall when lowered not located or aligned for optimum effectiveness attachment anchor points not sufficiently robust damaged and not maintained
incorrectly used – sometimes defeated
onsetter needs to adopt unsafe position to operate Tank traps can be defeated – transfer cars left in “straight through”
position
Bank doors can be left open
Barriers not located for optimum effectiveness not sufficiently robust
Stop blocks, chain sprags, aeroplane sprags etc.
not always provided not always used
Checklist of potential control limitations (contd) Conveyances and attachments
Control Potential Limitations
Conveyances
Design & selection failure to use specified purpose-designed units on inclines – standard mine cars sometimes used instead inadequate clearance over rope rollers in shaft
insufficient strength e.g. not always fitted with solid drawbars
incompatible coupling arrangements between cars Inspection/maintenance Wear and tear not identified
Damage not repaired timeously Attachments
Correct design/selection design criteria not always specified
non-standard attachments sometimes used
lack of spare/replacement equipment of correct standard Inspection/maintenance poorly defined allocation of responsibilities for
inspections
damaged attachments not replaced
correct inspection procedures not carried out Safety slings too long for given application
can be removed for other uses
correct inspection procedures not carried out damaged slings not replaced
not fitted with identification tags
confusion over dates stamped on identification tags
Shaft and shaft equipment maintenance
Control Potential Limitations
Shaft Inspections constrained by production pressures;
not formally logged and/or recorded;
visual/illumination restrictions
Checklist of potential control limitations (contd) Safe positioning
Control Potential Limitations
Prevent people taking up unsafe positions Guards and covers sometimes left off
Handrails/barriers etc damaged/not maintained
not located in the correct position gaps and discontinuities
not sufficiently robust mountings insecure handrails too low
Lock-bell systems not always interlocked with winder Demarcated safety
areas/refuges
design/arrangement provides only limited protection inappropriate provision and location
sometimes ignored need to work outside
Bank doors can be left open especially on steep incline shafts Warning people of risky situations
Visual warning/warning signs
line of sight restrictions not attention gaining not legible
damaged/not maintained Audible warnings warning can not be heard
damaged/not maintained Falling from heights
Control Potential Limitations
Access stairs, ladders, and walkways,
rungs too close to footwall
damage to handrails, rungs, platforms, backhoops etc excessive step heights
wet/Slippery surfaces
inadequate lighting and restricted vision uneven ground/floor conditions
insufficient handholds on temporary platforms Bank doors can be left open especially on steep incline shafts
can be too heavy and difficult to operate manually
Checklist of potential control limitations (contd) Falling from heights (contd)
Control Potential Limitations
Handrails, fencing barriers etc.
damaged/not maintained gaps and discontinuities not sufficiently robust mountings insecure Covers over
trenches/gullies
not provided not in place Personal protective
equipment
appropriate type not provided not always used/used incorrectly
User reliability
Control Potential Limitations
Driver’s desk design poor standard of control and instrument design restricted lines of sight/fields of vision
glare from sunlight and poorly located lights extremes of temperature
distractions from presence of unauthorised personnel Driver and onsetter
training
formal training based on use of different type of winder/system of operation
no provision of regular refresher training
induction and refresher training fails to address small winder issues
Pre-use inspections sometimes ignored
inappropriate documentation used failure to over-inspect
failure to follow up with remedial action Falling objects
Control Potential Limitations
Kickboards damaged/Not in place
Fail to prevent ingress of small items
Screens gaps in screens
too small and/or not strong enough damaged