The government was pretty blase about the risks from uranium back then. Obviously, the concentrated U-235 stuff was verboten, but uranium ore was considered non-dangerous, and the government basically encouraged all and sundry to mine for the stuff the same way one would mine for gold or silver.
Especially in the '50s. And yes, I have a couple of bits of uranium ore around, as I was head that way up until 3 Mile Island. Then I went to work in the oil patch, where neutron sources are kept tightly accounted for, and the gamma rays come from the rock itself...