Concrete base problem in garage shop. Any construction folks?

If your using clean limestone rock you will not be able to get it to pack, all you can do is run a roller or vibrating tamp over it to tamp it down best you can before pouring your new floor over top of it. Since your base is so deep probably be best to stay off it with any equipment like skid loaders / ready mix tricks after you get it leveled out where you wan it to prevent any
rutting prior or during r-mix placement.