The families of coal miners killed or injured inside Utah's Crandall Canyon mine, where six workers remain entombed, plan to sue two power agencies involved in operations.

The Los Angeles Department of Water and Power and the Utah-based Intermountain Power Agency should have known that dangerous conditions inside the mine would put workers at risk and lead to deaths, attorneys for the families said in letters to the agencies dated Tuesday and Wednesday.

Under California and Utah law, a governmental entity must receive notice of a lawsuit before it can be filed. Intermountain Power, whose members are municipal utilities, is co-owner of the mine, and the Los Angeles utility has a management role.

Both "caused or permitted mining activities to take place within the mine in an unreasonably dangerous and negligent manner," the families' attorneys said. Their letter said the lawsuits will seek unspecified damages for pain, suffering, loss of wages and other benefits.

Mine co-owner Murray Energy Corp. of Ohio and others will also be named as defendants, said Ed Havas, an attorney for the families.

Six miners more than 1,000 feet below ground died after the walls of a shaft imploded Aug. 6. Their bodies have not been recovered.

Ten days later, during an attempt to tunnel toward the group, three men died during another collapse. The mine is in Emery County, about 120 miles south of Salt Lake City.

Efforts to recover bodies from the mine ended Aug. 31. The shaft has been walled off with cinder blocks.

Two dozen survivors of the dead miners and two men injured during rescue efforts will be plaintiffs. The families of miner Dale Black and federal inspector Gary Jensen, who both died in the second cave-in, are not part of the case at this time, Havas said.

The Los Angeles agency has 45 days to respond and Intermountain Power has 60 days to respond before a lawsuit can be filed, Havas said.

Intermountain Power said in a statement that it continues to sympathize with those injured and the families of those killed.

"IPA respects the right of individuals or families to pursue legal recourse in the courts, and IPA trusts in the fairness of the judicial system to address such litigation," the agency said.

A telephone message left for the risk management department of the Los Angeles agency was not immediately returned.

Also Wednesday, a state commission formed after the cave-ins recommended a federal-state partnership to share mining plans and inspection reports and collaborate on ways to enhance safety.

The Utah Mine Safety Commission stopped short of suggesting that Utah create its own mine-safety agency, but the panel recommended a look at the feasibility of a state inspection program.

Utah has not regulated mines in 20 years, leaving the job to federal officials. West Virginia, Kentucky, Pennsylvania and other large mining states have their own safety agencies.

The mining industry has long opposed an independent state agency, saying it could cause headaches for mine operators and threaten the coal industry.

The president of the Utah Mining Association, David Litvin, was a member of the commission and wrote a separate statement in the report.

Litvin said a Utah inspection program would "blur the lines of responsibility between MSHA and the state, resulting in delay, confusion, complication and frustration in the state's coal mining industry."