Chilean President Sebastian Pinera holds up a plastic bag Sunday in Copiapo, Chile, containing a message from the trapped miners that reads, "We are OK in the refuge, the 33 miners." Hector Retamal/AP hide caption

itoggle caption Hector Retamal/AP

Don L. Blankenship, chairman and chief executive officer of Massey Energy Company (left), watches as protesters disrupt a luncheon at the National Press Club, where he spoke on Thursday. Wayne Huang/NPR hide caption

itoggle caption Wayne Huang/NPR

Methane monitors are mounted on 30-foot-long continuous miners like this one, and other mining machines, to warn coal miners about dangerous levels of explosive methane gas. File photo hide caption

itoggle caption File photo

Methane monitors are mounted on 30-foot-long continuous miners like this one because methane gas collects in pockets near the roofs of mines. File photo hide caption

itoggle caption File photo