Ledge!
Along the drive to our home sits in a linear line massive rocks bigger than the smart car.
We gather the builder had removed them when digging the foundation.
I have ledge in the front yard that has been incorporated with the fieldstone .
As part of my pool build I was quoted a two grand fee if we hit ledge and if we decided not to install a pool the cost would only be two grand.
I was also quoted a cost up to twenty grand to remove ledge.

We removed three huge rocks the size of volkswagons and ledge.
For additional 1800 they jack hammered off a section . The rock was massive and situated at the perimeter of the pool build.

I am fortunate that my property can contain the unearthed rocks and there is easy access to the pool dig site. The excavator equipment was massive.

The pool cost was 43 grand and quickly escalated . Hubby wanted a heat pump, I changed my mind to a different pebble tech product, the well water ran dry, and we needed to install a three sided wall . The pavers around the pool and the wall was an additional 25 grand.

You posted a few days ago so decisions needed to be made.
Ask all your options ,cost in writing, removal of rock off your site, and what additional changes will need to be done to support the pool.

If we attempted to remove the massive rock our driveway would have collapsed.

When they went to back hoe the dirt it was filled with rocks so I had to purchase 25 tons of irrigation sand.

Hoping your project moves forward.
If we hit ledge sooner I would have cancelled the pool build.
We hit ledge in the deep end five feet down.

I have cancelled the pool build with the original builder and have spoken to a PB that we had also received an estimate from. He said no way that it should cost as much as we were told to remove the rock. But there still is the issue of access with such a large machine. He is coming out to take a look next week. But his schedule is full for the summer, so if it works out we will not have a pool until late summer. Oh well.

I don't want to get into the situation that you found yourself in, where once the project begins the costs rise dramatically. But I'm sure you are happy that you have a pool now!