How long does it take to grind a stump?

We get asked regularly “How long it takes to grind stumps?”
The answer is controlled by many variations found on each individual job.
They include,
Size
Species
Condition
Climate
Ground
Geology
Altitude
Gradient
Access
Large trees have large stumps.
Hard timber cuts slower.
Dry old timber is harder again, rotten timber is softer.
Dry arid areas have tougher timber than high rainfall areas.
Rocky and sandy ground takes its toll on the machine and its wear parts, Teeth.
Ridgelines have more hard rock than slopes, and valleys have more sediment/soil.
High country plants are different to lowland plants and generally hardy like arid area vegetation.
Not all machines operate in steep country safely.
Small or restrictive access to the stumps mean that only smaller machines can get in, these smaller machines take longer to grind the stumps than larger machines with more power.

[@daviddonahue1862]

Are you using river wheel?

[@Northsidestumpgrinding]

No we are not using the New River Rev Lite wheel.
We are using the standard Green Teeth 900 series wheel.

[@OliverDiGeronimo009]

Wouldn't it make more sense to cut it to the ground with a chainsaw first?

[@Northsidestumpgrinding]

The stump has been burned. The carbon on the outside of this stump will wreck saw chain before you got halfway through.
A bigger machine is the faster option.