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 â¿¿ 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 â¿¿ which Grijalva said could total as much as $2 billion annually depending on production â¿¿ 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 â¿¿ home to most of the country's gold mining â¿¿ has been outspoken against past approaches to reform. However, his office said he remains open-minded on the royalty issue. "He's willing to consider any proposal for mining reform that shares revenues with the state, protects the mining industry and doesn't kill jobs," said Kristen Orthman, Reid's spokeswoman. 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.