The specter of giant gold-mining rigs chewing into the slopes of the Sierra and spewing toxins into Yosemite National Park has an environmental group fanning out across California collecting petitions to ban mining within 10 miles of the park.
Environment California, a nonprofit advocacy group, hopes to gather 50,000 signatures by the end of the summer asking President Barack Obama for a ban like the one his administration enacted in January forbidding new mining claims near the Grand Canyon.
There aren't any big industrial mining operations active now near Yosemite, advocates of a ban said. But with the price of gold having tripled in recent years, there has been a rush to stake out mining claims in the historic Gold Rush areas around the park.
At any time, mining opponents say, any of these could be turned into a huge dig site.
"Industrial mining is one of the biggest, dirtiest and most dangerous businesses around," said Dan Jacobson, legislative director of the group. "Obviously, you don't want that around the crown jewel of American parks."
Mining has long been prohibited within Yosemite, but there are 185 mining claims recorded within 10 miles of park borders, mostly in the Stanislaus National Forest. More than half of those have been staked out since 2006 -- when gold was selling for only $500 an ounce -- according to a report by the Pew Environment Group.
"Most of those are mom-and-pop operations," Jacobson said. "But no matter how small they are, there is always the threat of them selling to a big company if they find significant gold there and becoming big."
He pointed out that, to this day, mercury, lead and cyanide contamination exists throughout the Sierra from Gold Rush-era mining operations. Any such contamination today, he said, could poison peregrine falcons, black bears and other wildlife "that don't recognize borders and fly over from Yosemite."
Mining advocates scoff at Jacobson's fears, and say a ban would infringe on business and individual rights.
"The technology has come a long way and the country has, too, since the old days of mining," said Mark Compton, government-affairs manager for the Northwest Mining Association, an industry advocacy group. "There are systems in place now to make sure cyanide and other chemicals don't go leaching into the watershed."
Among those holding a claim within 10 miles of Yosemite are directors of the Gold Prospectors Association of America, which encourages anyone with a lust for nuggets to head up the mountainsides.
"I don't think these radical environmental groups have a clue about what gold mining is about," said Brad Jones, editor at the association. "They're looking at how mining used to be 150 years ago. They're thinking of old practices like using huge water cannons to erode whole mountainsides, things that have been outlawed for decades."
Yosemite National Park spokesman Scott Gediman said he can understand the interest in whether there's gold in them thar hills. Mining has been prohibited in Yosemite since President Abraham Lincoln set the land aside as a forest reserve in 1864, he said, but plenty of wallets have been filled by mining money earned just outside park borders in places like Mariposa.
"The area is rich in mining history -- this is the Mother Lode, after all," Gediman said. "We don't have yes-or-no authority on mining operations nearby, but obviously we'd be concerned if there was any potential water or air pollution.
"There's a lot of hurdles an operation would have to go over, however," Gediman said. "And yes, an operation could potentially spill into the park. But do we feel these claims outside the park are immediate threats? No."
(Kevin Fagan is a San Francisco Chronicle staff writer. Email email@example.com. For more stories, visit scrippsnews.com.)