Some sites that give background and a few snippits of...

Some sites that give background and a few snippits of information of economic concentrations and in what countries the known world reserves are.

http://www.world-nuclear.org/education/mining.htm

http://www.em.gov.bc.ca/Mining/Geolsurv/MetallicMinerals/MineralDepositProfiles/Profiles/I15.htm

http://en.wikipedia.org/wiki/Uranium#Uranium_exploration_and_mining