On April 5, 2010, a massive explosion rocked Massy Energy subsidiary Performance Coal Company’s Upper Big Branch mine at Montcoal.

Twenty-nine miners died, and two were injured in the blast.

Here is a timeline of events (times are approximate):

Day 1 - Monday, April 5, 2010

- Shortly after 3 p.m.: Carbon monoxide alarms in the mine go off. This is likely the time of the explosion.

- The explosion occurs at or around a shift change. Sixty-one miners were in the mine at the time. Miner Steve Smith, who hears the explosion but escapes, said, “Before you knew it, it was just like your ears stopped up. You couldn’t hear. And the next thing you know, it’s just like you’re just right in the middle of a tornado.”

- Some miners leaving the mine feel a rush of air and return to investigate. They find nine miners who were headed out of the mine. Two of the nine are injured and helped to safety.

-  The miners try to find others but are stopped by high levels of carbon monoxide.

3:27 p.m.: The company notifies the Mine Safety and Health Administration (MSHA) and the West Virginia Department of Miners’ Health, Safety and Training of the explosion.

- More than 20 mine emergency rescue teams respond.

Around 5:30 p.m.:  First rescue teams enter the mine.  Extensive damage from the explosion makes progress difficult.  Rescuers are only able to note the locations of deceased miners, not identify them, moving on in hopes of finding someone alive. There has been no radio communication from the miners.

- Officials say there are underground refuge chambers designed to sustain life for 96 hours, should any survivors make it to one.

- One of the injured miners is transported to Raleigh General Hospital, and a second is airlifted to Charleston Area Medical Center.

- Kevin Stricklin, an administrator for MSHA, says the teams’ mission is rescue, not recovery, with teams changing every two hours.

- Family members are taken to the old Pettus Elementary School near the mine site, where they are kept abreast of the situation.

8:10 p.m.: Massey Energy Chairman and CEO Don Blankenship issues a statement confirming seven miners dead, two injured and 19 unaccounted for.

Day 2 - Tuesday, April 6, 2010

1:40 a.m.: Massey confirms that 25 miners are dead and four are missing.

2:30 a.m.: Rescue workers are forced to abandon their efforts after encountering heavy smoke, methane and carbon monoxide.

- Crews plan to drill shafts to vent methane and carbon monoxide from the mine and make it safe for rescuers. Bulldozers carve a road to make a way for drilling crews.

-  Gov. Joe Manchin mentions hope, but Stricklin holds out little “based on what I’m seeing and hearing from the people underground.”

- Drilling begins on two side-by-side vent shafts.

10 a.m.: President Barack Obama urges prayers for miners and their families.

Noon: Kevin Stricklin says “It’s quite evident that something went very wrong here. All explosions are preventable. It’s just making sure you have all the things in place to keep one from occurring.”

- Massey Energy was fined more than $382,000 in the past year for repeated serious violation involving its ventilation and equipment at the mine. Blankenship says the mine was not unsafe, but federal regulators plan to review its violations.

- Stricklin says he is concerned about an initial review of the more serious violations, which indicated that “the operator was aware of some of these conditions.”

- The death toll is now the highest in a U.S. mine since 1984, when 27 people died in a fire at Emery Mining Corp.’s mine in Orangeville, Utah.

Day 3 - Wednesday, April 7, 2010

4 a.m.: The first hole is drilled through to the mine site. There is no response from possible survivors after rescue workers bang on a drill pipe.

Noon: MSHA announces a team has been formed to begin a probe into the explosion.

4 p.m.: Levels of toxic gases are still too high for rescuers to re-enter the mine. Plans are made to drill an additional hole and lower a camera near a rescue chamber to try to locate the miners.

- West Virginia University coach Bob Huggins visits the waiting families, bringing homemade pasta.

- Some families begin making funeral arrangements for their loved ones.

9 p.m.:  MSHA announces that air quality has improved and rescue workers plan to re-enter the mine.

Day 4 - Thursday, April 8, 2010

5 a.m.: Rescuers re-enter the mine after monitoring air quality all night.

9 a.m.: Rescuers travel by mantrip and on foot to a point about 5 miles into the mine when they are forced to stop and exit because of dangerous gases. They are able to leave behind equipment, which will allow them to move more quickly once they can get back into the mine.

- Crews resume drilling boreholes for ventilation into the mine.

- The injured miner at Raleigh General Hospital is released, but his family asks for privacy.

Day 5 - Friday, April 9, 2010

12:30 a.m.:  Two rescue teams enter the mine after air conditions are deemed safe enough.

7 a.m.: They are again forced to retreat early after smoke was found, indicating a fire somewhere in the mine.

- Rescuers reach one of two underground emergency shelters, finding it had not been deployed. They are forced to abandon the search, however, before checking the second rescue chamber.

- Stricklin says crews have begun pumping nitrogen into the mine in hopes of neutralizing potentially explosive gases and allowing rescuers to go back in.

2:30 p.m.: Two eight-member rescue teams go back underground; Stricklin says it will take crews three-and-a-half to four hours to reach the second emergency chamber.

- Funerals for four of the victims whose bodies were recovered earlier are held.

Day 6 - Saturday, April 10, 2010

- Manchin announces early Saturday morning that the four missing miners had been found dead. “We did not receive the miracle that we prayed for,” the governor said. “So this journey has ended, and now the healing will start.”

- The mission turns from rescue to recovery as crews begin carrying the remaining bodies from the mine.

- With the death toll now at 29, the explosion at Performance Coal Company’s Upper Big Branch mine officially becomes the worst mining disaster in the U.S. since 1970, when 38 miners died in an explosion in Hyden, Ky.

- Two more funerals are held.

- Hundreds of people gather near Marsh Fork Elementary School to honor the lost miners.

Day 7 - Sunday, April 11, 2010

- Recovery operations are suspended after high levels of toxic gas are detected. The readings are in an area of the mine where the explosion occurred.

- Crews drill another hole to vent gases so that when gas levels are safe, the recovery

operation can begin again.

Day 8 - Monday, April 12, 2010

- Manchin and wife Gayle place a wreath at the miner statue on the State Capitol grounds. People are asked to observe a moment of silence at 3 p.m., a week to the hour of the fatal explosion.

- State flags are lowered to half-staff.

- MSHA officials arrive to begin a probe into the disaster. At the same time, the state is performing a separate investigation through the Health, Safety and Training Office.

Day 9 - Tuesday, April 13, 2010

- The last of the victims are recovered from the mine.

- Manchin names Davitt McAteer, former assistant secretary of the federal Mine Safety and Health Administration, to head up an inquiry independent of separate probes by state and federal mining regulators.

Sunday, April 26, 2010

- A memorial service is held at the Beckley-Raleigh County Convention Center. Nearly 3,000 people and a host of dignitaries including President Barack Obama, Vice President Joe Biden, Gov. Joe Manchin, U.S. Sens. Jay Rockefeller and Robert C. Byrd, and U.S. Reps. Nick J. Rahall and Shelley Moore Capito attend. President Obama reads each of the 29 miners’ names.

SOURCES: MSHA, The Register-Herald