An old mining law in the US is threatening the country’s natural treasures, including the Grand Canyon National park, as mining claims on public lands increase, according a report by PEW environmental group.

The 1872 mining law, which was signed by President Ulysses Grant, states that mining companies, including foreign-owned ones, can take about $1bn a year in gold and other metals from public lands without paying a royalty.

Pew’s report has urged the Obama administration to use its power to protect these sites and work with congress to modernise the law that still governs hard rock mining on public lands in the west of the country.

According to the report, ten national parks are under threat: Yosemite, Arches, Canyonlands and Joshua Tree National Parks; Mount Rushmore National Memorial in South Dakota; Mount St. Helens National Volcanic Monument in Washington; Siskiyou Wild Rivers in Oregon; Gila Wilderness in New Mexico; and Dinosaur National Monument in Colorado and Utah.