The federal government doesn't even know how much these so-called "hard rock" mines produce from federal public lands in the 12 western states where most of the mining occurs, the Government Accountability Office report found.
And there is no federal law requiring the disclosure of production figures from individual mines.
Two Democratic lawmakers are hoping public concerns over the economy and the looming "fiscal cliff" will reinvigorate a movement on Capitol Hill to reform the General Mining Act of 1872, which exempted mining companies from paying royalties for profiting from U.S. public lands.
They want miners to pay the same 12.5 percent in royalties as oil companies, a move that could bring hundreds of millions of dollars in new annual revenue.
The 1872 law "was designed to perpetuate the 'go west, young man' idea to bring people, commerce and industry to the West. But that's done, it's the new West now," said Rep. Raul Grijalva, D-Ariz., who along with Sen. Tom Udall, D-New Mexico, requested the GAO study.
The U.S. Department of the Interior collected $11.3 billion in 2010 and $11.4 billion in 2011 from oil, coal and natural gas royalties and leases, the report found.
The mining industry, which has fought to kill similar reform bills, said it already pays billions in taxes involving mines located on state and private lands.
"In 2008, there were $20 billion in sales in U.S. metals, and we paid about $8.3 billion in various taxes on that," said Carol Raulston, a spokeswoman for the National Mining Association. She said the industry supports fair compensation for the government but not a royalty comparable to what is paid by the oil industry.
Grijalva and Udall said they plan to make their case in the next session of Congress. Grijalva said he intends to introduce a bill calling for royalties on the mining of metals on public land.
"We can't ignore these potential revenues any longer not when the American people are counting on us to solve our economic challenges," Udall said in a statement. "Hard rock mining reform should be part of that discussion."
The new revenue which Grijalva said could total as much as $2 billion annually depending on production might be used for cleaning up abandoned mines, national parks and public lands. The bill would also require companies to disclose production levels on federal lands.
"The mining industry is a very powerful lobby, and they've basically kept the hands-off attitude," Grijalva said, explaining previous failed attempts at reform.
The GAO estimated the value of hard rock minerals mined on federal lands in 2011 was about $6.4 billion. If the industry paid royalties comparable to oil companies, the federal government would have received $800 million in royalties from those mines.
The mining industry opposed a similar bill that passed the House in 2008 but died in the Senate the following year.
Other Democrats in Congress do not agree on mining reform.
Senate Majority Leader Harry Reid of Nevada home to most of the country's gold mining has been outspoken about past reform efforts.
His office didn't return a message seeking comment, but Reid has said he supports reform but cautioned that "we've got to work out what (industry) wants, and I will take care of them," he told the Elko Daily Free Press in 2010.
The mining association's Raulston said the industry is not opposed to royalties in theory but believes charging a rate comparable to oil, coal and natural gas is unfair.
"Metals are not immediately sellable products there are processes and refining needed to get out the impurities," she said. "So, there are added costs in metals mining that you don't see in other natural resources like timber, gas and coal."
Supporters of royalties such as Grijalva say reform is overdue and multinational mining companies that profit from U.S. public lands should be paying.
"We're not dealing with a grub stake or prospector going out there, but multinational companies that end up exporting most of the minerals they take out," Grijalva said. "And we're getting nothing back for taxpayers to maintain parks, offset the deficit and to clean up abandon mines all over the West."