fig7

Figure 7. BSE images of a liberated ((A and D), WAL 20), a partially encapsulated ((B and E), WAL 14), and a completely encapsulated ((C and F), WAL 15) REE-baring particle found in the Western Kentucky No. 13 material. ((A-C) and (D-F) were taken with an accelerating voltage of 20 kV and 10 kV, respectively). BSE: Backscattered electron; REE: rare earth element.