A lifeline for two Native-American tribes in Arizona could be cut off.

Dozens of coal miners from the Navajo Nation packed a public hearing in Phoenix Monday to plead for their jobs.

The power plant they supply could shut down as soon as this year. That plant -- the Navajo Generating Station near Page -- pumps Colorado River water to the Phoenix area and Tucson.

Nearly a thousand Navajo and Hopi would lose their jobs.

"Coal mining is harsh, hard, dangerous business," said Allen Martin, who's been working at the mine for 42 years. "We know our business, we know how to do it, and we've been providing it for everybody."

There is nothing else like these jobs on the tribal reservations. They're high-paying, with good benefits.

"People are moving, making pretty dramatic choices right now," said Myron Richardson, a supervisor at the Kayenta mine, owned by Peabody Energy.

Power plant owner Salt River Project says it can get cheaper power from natural gas.

"It's about, 'What is the cost of other resources we can get on behalf of our customers?' That's natural gas. It's much cheaper and it is reliable," said Scott Harelson, a spokesman for SRP.

But the Navajo worry about a lost generation of young people, forced to leave the reservation in search of work.

"It's wrong to do what they're doing, to a nation -- to two nations, actually," said Marie Justice, the leader of the coal miners union.