Gov. Joe Manchin signed new mining rules into law Thursday, saying they would help prevent future tragedies like those that killed 14 miners this month and injured another.

"We want to be the benchmark everyone looks to when they mine," Manchin said during the signing ceremony, attended by miners' relatives. "The sacrifice you all have made will change mining in this country."

State lawmakers passed the legislation unanimously just days after a Jan. 19 mine fire killed two men, and about three weeks after an explosion at another mine resulted in the deaths of 12 miners.

The only survivor among the trapped miners, Randal McCloy Jr., 26, emerged from a light coma Wednesday but still cannot speak.

The state's new mine safety law mandates that miners be provided with emergency communicators and tracking devices. It also requires mine operators to store extra air supplies underground, and sets up a new Mine and Industrial Accident Rapid Response System and statewide all-hours hot line to trigger rescue efforts more quickly.

Investigators Thursday were expected to get into the Sago Mine soon to start determining what sparked the explosion that led to the 12 deaths, most of them from carbon monoxide poisoning.

The investigation had been held up, first by the dangerous gases and then over a dispute between the United Mine Workers and the mine's owner over the union's demand to accompany investigators.

A federal judge ruled Thursday that union representatives could participate in the exploratory investigation. The federal Mine Safety and Health Administration, which had already recognized the union as legal representative for several workers at the nonunion mine, supported granting access.

Under the new state law, miners would be directed to the extra air supplies kept inside the mine by strobe lights, reflective signs and guide ropes.

Some companies already provide extra air supplies, but in most cases, miners only carry canisters that provide up to an hour's worth of oxygen.

The new law also addresses communications, requiring companies to install low frequency, wireless systems that connect miners to the surface through a series of transponders and requiring tracking devices for miners. Most U.S. mines still rely heavily on hard-wired communication systems, rescue teams were unable to communicate with the trapped Sago miners because the system was damaged.

Coal companies that fail to report an emergency within 15 minutes would also face the threat of $100,000 fines under the law. At Sago, company officials placed the first calls to state and federal safety officials more than an hour after the explosion.

While industry officials have raised questions about the reliability of the technology involved, they helped Manchin's office craft the legislation and have said they will support it. The United Mine Workers Union also consulted with Manchin on the bill.

State mine officials must now write the rules necessary to carry out the new law. A deadline for coal companies to comply with its provisions has not yet been announced.