I must be confused again...I had long thought that BLM grazing allotments went with a Base Ranch and couldn't be sold separately. Heck, its not easy to even transfer grazing rights along with a ranch lease...there is a lot of paper work involved with the BLM and it's even more difficult on US Forest Service allotments.
You don't suppose that the rules which I have to obey were bent slightly???
The article doesn't mention it, but I'm sure they also purchased the base property to which the grazing rights were attached. For BLM, the base property can be either land or water.