They are, in many ways, like a honey bee hive. They have "honey pots" that they build out of wax that have either brood, pollen or honey in them. They will not abondon the brood to go somewhere else. About the only way to get them to leave is to remove them all, fill in where the nest was (if below ground) or destroy the nest (if above ground) and they will hopefully settle somewhere else.
IF I were going to attempt this, and I probably wouldn't, I would put on a full bee suit, rubber band the ankles and sleaves, wear gloves and a zip on veil. Use a water hose to hose down the bees and the nest so they can't fly. Remove all the nest materials and scatter them and the bees off away from the original site. A shovel would be a good tool for this, but if you don't want to harm the bees, you'll have to be careful. When all of the bees and nesting materials are removed, fill in the mouse hole nest (probably the source of the hole in the ground that the bumble bees are living in) and pack it down well.
Be prepared to get stung. :) And remember a bumble bee can do this repeatedly.