The bill was unveiled as a “comprehensive” proposal by Tomblin that served to respond in part to the April 2010 Upper Big Branch mine explosion that killed 29 people.

The governor signed the bill along with other new pieces of legislation late last week but marked House Bill 4351’s passage with a ceremony on Wednesday afternoon.

Tomblin’s legislation includes several improvements to mine safety, including a strengthening of requirements for rock dusting and methane standards.

Both are believed by many experts to have been significant contributors to the UBB blast.

Specifically, rock dust percentages at the state’s mines have risen from 65% to 80%.

Also, electrical machines brought inby the last open crosscut are prohibited if methane exceeds 1%.

Mines will be required to shut off electric equipment if methane spikes above 1.2% in that area and all personnel must be evacuated if levels exceed 1.5%.

Fines and penalties are now higher for those individuals at West Virginia operations who provide advance notice of an inspector’s presence or who willfully violate any safety standard that causes a fatality.

Pre-notification will be a felony charge carrying a potential jail sentence of five years.

Bi-weekly reviews of fire boss records will be ordered under the new law and an anonymous hotline for safety issue reporting will be codified.

The much-discussed drug testing proposals Tomblin introduced under the initial bill are also now safety standards.

In addition to current testing protocols, inspectors can order a drug test for individuals with reasonable cause, or if impairment or abuse is believed to have contributed to an accident.

Pre-employment drug screens that include temporary suspension of one’s certification for a failure will be mandatory.

One amendment made at the Senate level earlier this month is now law, outlining that an underground boss no longer needs to report to a certified worker on the surface when traveling from section to section, as that individual is not always available.

“I'm proud of our state’s mine industry, I’m proud of our coal miners and I’m proud we have passed this legislation,” Tomblin said on Wednesday at the Charleston signing ceremony.

“Coal mining in West Virginia will be safer as a result our foresight and hard work.

“Again, I'd like to commend both the members and leadership of the House of Delegates and the Senate for working to ensure the safety of our coal miners.”

Tomblin proposal took its first step towards approval in mid-February, following its endorsement by the state’s House Judiciary Committee.