What's Going On?

This activity is what we saw when we parked to go to our yoga class in Fairhaven today. There will soon be (expensive) condos on this site.

I'd never seen anything like it before. The red machine was dumping loads of gravel into the hopper of the big yellow one, which appeared to be injecting it into previously-drilled holes. I suspect that cement and water are added and mixed in the cylinder at the top of the shaft. Presto -- concrete pilings! Perhaps another blipper can confirm my theory?