The DOT labels are fuzzy but look to be yellow on top. Is someone burying radioactive waste?
Very mildly radioactive material, not necessarily waste.
A friend posted a link to an article that appeared in The Telegraph (UK) on Sunday. it was about an approach to nuclear power. I was merrily reading along when I saw "The Americans have buried tonnes of it, a hazardous by-product of rare earth metal mining." I googled "burial" and the name of the stuff the article was talking about and the above picture came up. What a lucky break.