Two years ago today, 29 men died in a West Virginia coal mine

"When the world came to an end" is how Joshua Williams described being inside the Upper Big Branch coal mine at 3:02 pm on April 5, 2010. He knew several crews of coal miners were much deeper inside the dark tunnels than he. An ominous feeling. Coal dust explosions are powerful and deadly. Eight days later, after all the worker-victims were removed from the mine, the death toll was 29.

What's happened in the two years since the disaster? Here's a brief recap:

• Eighty-four mine workers at other U.S. mining operations have been killed on-the-job since the April 2010 Upper Big Branch disaster. Forty-four of the fatal injuries occurred at coal mines, with the others at gold, silver, phosphate, limestone, salt, copper, uranium, granite, and sand and gravel operations. Nationwide, about 5,000 workers are killed on-the-job from traumatic fatal injuries annually, and thousands more die from work-related diseases.

• Four different investigative bodies examined the factors that lead to the Upper Big Branch disaster and reached the same conclusion about how the explosion happened: A pocket of methane gas at the tail-end of the longwall mining machine ignited, due to ineffective water sprays and ventilation, picked up more methane fuel and suspended coal dust to create a massive dust explosions. They also agreed on the cause of the disaster: a company that disregarded fundamental safety practices to maximize its profit. Reports by the WV Governor's Independent Panel (here), Mine Safety and Health Administration (here), United Mine Workers (here) and State of West Virginia (here)) were issued in May 2011, October 2011, December 2011, and February 2012, respectively.

• Massey Energy, the owner at-the-time of the Upper Big Branch mine, released in June 2011 its own report on the disaster. The company attributed the explosion to a massive inundation of natural gas, an "act of God" that could not have been prevented.

• Alpha Natural Resources purchased Massey Energy in January 2011 in a deal worth more than $7 billion. Former Massey Energy CEO Don Blankenship received an $86 million payout in the deal.

• The U.S. Department of Justice and Alpha Natural Resources entered into a non-prosecution agreement in December 2011 in which the firm agreed to pay $209 million toward investments in mine safety equipment, new technology and research, restitution to the victims' families, and to wipe its slate clean of delinquent penalties for safety violations.

• MSHA issued an emergency temporary standard in September 2010 increasing the requirements for the application of incombustible "rock dust" to prevent coal dust explosions in underground coal mines. The regulation was based on a recommendation made in 2006 and 2009 by NIOSH.

• MSHA proposed in December 2010 and will be issuing this week, a revision to its regulation concerning mandatory examinations of work areas in underground coal mines. Miners conducting pre-shift, on-shift and other examinations of the underground work environment will be explicitly required to record both hazardous conditions and violations of nine specific safety standards, including ventilation, roof control, accumulated coal dust and machine guarding.

• MSHA has the authority under the Federal Mine Safety and Health Act to identify mines with a "pattern of violations" of mandatory standards, give the mine operator notice that this unacceptable behavior exists, and if the situation is not rectified, order workers withdrawn from the mine and seek an injunction in court to protect their safety. In the 30 years prior to the Upper Big Branch disaster, not a single mine operator met MSHA's criteria for a pattern of violation. In the two years since the disaster, two mines have recevied this designation. Moreover, in February 2011, MSHA proposed changes to its regulations defining the pattern of violation process, and indicated in January 2012 that it expected to issue the new regulation in April 2012. MSHA may miss this target date; it doesn't appear the agency has submitted it yet to the White House's Office of Management and Budget for their review.

• Several Members of Congress introduced legislation to remedy some weaknesses in the current MSHA statute and regulations. Senator Jay Rockefeller (D-WV) and Congressman George Miller (D-CA) introduced the Robert C. Byrd Mine Safety Protection Act (H.R. 1579 and S. 153) and Congresswoman Shelley Moore Capito (R-WV) introduced the Mine Safety Accountability and Improved Protection Act (H.R. 3697.) All three bills would create an independent panel to investigate certain mining fatalities, revise the pattern of violation procedures, allow MSHA to revoke inadequate mining plans, and increase penalties for "bad actor" mine operators. Congressman Miller's bill would extend some provisions to gassy, non-coal mines, while Senator Rockefeller's bill includes a section addressing weaknesses in the Occupational Safety and Health Act, including whistleblower rights, hazard abatement, and modernizing civil and criminal penalties. Neither the House Republican leadership or the Senate Democratic leadership have held hearings on these bills.

• Mr. Hughie Elbert Stover, 60, the former security chief for Massey Energy, was sentenced in February 2012 to three years in jail, two years probation and a $20,000 fine for obstructing the federal government's investigation of the disaster.

• Mr. Gary May, 43, a mine superintendent at the Upper Big Branch mine, plead guilty to conspiracy charges for his actions to deceive mine safety inspectors from finding hazardous conditions in the mine. Mr. May will be sentenced in August and could face up to five years in prison.

• The Governor of West Virginia signed a bill in March 2012 on new mine safety requirements for underground coal mines in the State. These include requiring methane detectors be maintained in accordance with manufacture specifications, updating rock dusting requirements (a repeat of the MSHA rule described above), and mandating drug-testing for requires pre-employment and random drug testing (although drug abuse had nothing to do with the Upper Big Branch disaster.)

• Two investigative bodies examined the effectiveness of MSHA's enforcement activities at the Upper Big Branch mine in the months leading up to the disaster. The agency's own internal review attributed its deficiencies to the inexperience of inspectors, and inadequate direction, training, and supervision, in the particular local office responsible for inspecting the mine. A report prepared by a four-person panel convened by NIOSH was more blunt, saying "if MSHA had engaged in timely enforcement of the Mine Act and applicable standards and regulations, it would have lessened the chances of -- and possibly could have prevented -- the UBB explosion."

• Ken Ward, Jr. has written more than 200 articles for the Charleston (WV) Gazette about the disaster, its impact on the deceased miners' families, the employer's and government's culpability, and efforts to hold responsible parties accountable. His article today simply reminds us of each of the 29 miners' names.

A two-minute tribute that gives a glimpse of their personalities is here, courtesty of the Charleston Gazette's Douglas Imbrogno. Have a tissue in hand.