How do you achieve the best cost per hour results when operating with ground engaging tools (GET) in mining and earthmoving applications?
If your goal is to achieve the lowest possible cost per operating hour on your ground engaging tools in mining and earthmoving then you cannot manage GET simply on purchase price versus hours.
You need to manage the total cost of the machine while fitted with the correct ground engaging tools package.
The keys to managing ground engaging tools and cost per hour
The lowest GET cost/hour = GET cost + downtime + lost production + secondary component damage, divided by productive operating hours.
Some of the OEM’s emphasise balancing penetration, wear life and productivity, rather than simply buying the longest-lasting or cheapest GET package.
1. Measure every ground engaging tools set properly
1. Measure every ground engaging tools set properly
| Measurement | What to record |
| Machine | D8, D10, D11, 336, 390, 994, etc. |
| Application | Coal, overburden, hard rock, waste, sand, gravel |
| GET part number | Exact OEM/aftermarket number |
| Purchase price | R/set or R/component |
| Installation hours | Labour + machine downtime |
| Start hours | Hour-meter reading |
| Removal hours | Hour-meter reading |
| Life achieved | Operating hours |
| Material moved | Tonnes or m³ |
| Fuel | If available |
| Condition at removal | % wear |
| Failures | Broken/cracked/missing components |
| Production effect | Tonnes/hour or cycles/hour |
Then calculate the ground engaging tools cost per hour:
GET cost/hour = Total GET lifecycle cost ÷ GET operating hours
Take it one step further:
GET cost/tonne = Total GET lifecycle cost ÷ tonnes moved
That second number can completely change which of the ground engaging tools options is actually the most cost effective.
2. Don’t buy the cheapest ground engaging tools — buy the cheapest for the application
This is probably the biggest opportunity.
For example, if a R50,000 GET set lasts 1,000 hours:
R50/hour
A R70,000 set lasting 1,700 hours:
R41.18/hour
The second set of ground engaging tools is 40% more expensive at initial purchase, but 18% cheaper per hour. If the second ground engaging tools set also gives better penetration and productivity, its real advantage could be considerably greater.
Centrax specifically recommends matching GET geometry and wear characteristics to the material and application. We are happy to consult on your GET needs at no cost to you providing you with the best cost per hour for your ground engaging tools.
3. Separate your machines into application groups
Don’t use one ground engaging tools specification across the whole fleet.
Try to establish at least these categories:
1.Abrasive
- Quartzite
- Hard rock
- Highly abrasive overburden
- Gravel
2.High impact
- Large rock
- Shot rock
- Blasted material
- Fractured hard material
3.High penetration
- Compact clay
- Hard-packed overburden
- Frozen/compacted material
4.General earthmoving
- Soil
- Soft overburden
- Sand
- Normal aggregate
The correct ground engaging tools can be dramatically different between these applications.
For example, some ranges of GET include general-purpose, heavy-duty, penetration, heavy-penetration and heavy-abrasion designs specifically because more wear material isn’t necessarily always the answer.
4.Establish a proper “change-out point”
This is where many mines lose money.
Don’t run any ground engaging tools to complete destruction.
Once GET is excessively worn, it can start transferring wear into the expensive component behind it.
For example:
Tooth → adapter → lip → bucket
or
Cutting edge → blade/moldboard
In these scenarios relatively inexpensive GET can cause an extremely expensive repair.
Some manufacturers specifically warn that allowing ground engaging tools to exceed their useful wear life can increase contact area and resistance, requiring more horsepower leading to increased fuel consumption and reducing efficiency.
So you want to determine:
At what percentage of GET wear does another hour of life become more expensive than simply replacing it?
That is your economic change-out point.
It may be 80%, 85%, 90% etc. depending on the application.
We can assist you in determining these change-out points on your fleet of machines.
5. Measure wear — don’t rely on the operator saying “it looks okay”
This is particularly important for mining that run expensive ground engaging tool packages.
Establish a GET inspection programme.
For example:
Every 100 operating hours measure:
- Tooth length
- Cutting-edge thickness
- End-bit thickness
- Adapter wear
- Lip wear
- Side-cutter wear
- Ripper-tip wear
- Cracks
- Retainer condition
- Bolt condition
Then plot:
Wear percentage versus operating hours
You can then predict for e.g. these ground engaging tools have approximately 180 hours of usable life left.
That allows you to plan the change rather than having an unplanned failure.
Some manufacturers also promote inspection and digital monitoring as ways of managing GET performance and planning maintenance.
6. Track the operator as well as the ground engaging tools
This is a massive factor in determining the real cost of ground engaging tools.
Two identical D10s working in the same pit can get dramatically different GET life due to operator performance.
Look at:
- Excessive penetration
- Track spinning
- Excessive blade angle
- Incorrect ripping technique
- Carrying material unnecessarily
- Working at incorrect speeds
- Excessive impact
- Digging at the wrong angle
- Using the blade to break material that should have been ripped/blasted
In these scenarios you want to identify:
Machine + operator + material + GET = actual result, rather than simply blaming the GET manufacturer for poor performance.
7. Track GET performance by machine
Create a ranking table for your ground engaging tools like the below:
| Machine | GET | Hours | Cost | R/hr | Tonnes | R/tonne |
| D10 #1 | OEM | 1,250 | R92,000 | R73.60 | 850,000 | R0.108 |
| D10 #2 | Brand B | 1,480 | R84,000 | R56.76 | 920,000 | R0.091 |
| D10 #3 | Brand C | 1,100 | R69,000 | R62.73 | 790,000 | R0.087 |
Notice something important:
Brand C has the highest hourly cost after Brand B?
But it has the lowest cost per tonne.
Pro Tip:
That’s why we strongly recommend measuring both R/hour and R/tonne.
8. Don’t ignore downtime
Suppose:
GET A costs R60/hour
GET B costs R75/hour
At first glance A wins.
But suppose B lasts 1,500 hours while A lasts 1,000 hours.
A requires one additional change-out every 1,500 hours.
If the machine loses 6 hours each time then:
6 hours × machine production value can easily wipe out the apparent GET saving.
9. Run controlled ground engaging tools trials
Take one machine/application and conduct a controlled comparison.
For example:
Trial A
OEM GET
Trial B
Aftermarket GET
Keep as many variables as constant as possible:
- Same machine
- Same operator
- Same material
- Same working area
- Same operating conditions
- Same inspection intervals
Measure:
Purchase price → hours → wear → tonnes → downtime → R/hour → R/tonne
Do this over at least several sets, not just one.
One set of ground engaging tools can be an outlier.
10. The most important KPI we suggest
If you’re managing your ground engaging tools correctly then build it around this:
GET Cost Performance Index
CPI = Total GET cost ÷ productive tonnes moved
Then separately report:
- R/hour
- R/tonne
- GET life hours
- GET downtime hours
- GET failures
- Production tonnes/hour
This will give you a much more credible picture than simply saying:
The tooth lasts 1,500 hours.
Because 1,500 hours isn’t necessarily better if the machine is producing less during those hours.
11. The “sweet spot”
The optimum ground engaging tools set isn’t necessarily:
Longest life
and it isn’t:
Lowest purchase price.
It is:
Maximum production × maximum useful wear life ÷ minimum total lifecycle cost
That’s why the right ground engaging tools can sometimes be more aggressive in the penetrating design rather than the heaviest piece of steel available. The objective is balancing penetration and wear life to improve productivity and lower cost per hour.
If you need assistance with ground engaging tools management
speak to our experienced get specialists for the right application get that achieves the best cost per hour
