Apple has promised to source gold for its electronic products from miners registered under the Salmon Gold partnership, a scheme where miners open up old mining sites to search for gold and in the process take steps to improve nearby watercourses for salmon.

As part of the technology's giant's pledge to use only recycled or renewable materials, Apple ultimately aims to end its reliance on mining.

As a step towards that goal, it announced it has partnered with Salmon Gold to source gold from mines registered with the scheme. It added that from the autumn all the gold sourced from Salmon Gold mines will be traced from the mine to the refiner using blockchain technology.

U.S. jewelry maker Tiffany also has promised to source gold from the Salmon Gold certified mines.

"As we continue to increase our use of recycled materials, we're seeking out innovative ways to source gold responsibly," said Paula Pyers, Apple's head of supplier responsibility. "Partnering with Tiffany, a pioneer in sustainable sourcing, as well as RESOLVE ensures Salmon Gold can be an example of how the industry can evolve."

Hundreds of small and large gold mines dot creeks and streams in Alaska, a legacy of the 1890s Klondike Gold Rush when around 100,000 prospectors migrated to the Klondike region of the Yukon.

Hundreds of small and large gold mines dot creeks and streams in Alaska, a legacy of the 1890s Klondike Gold Rush when around 100,000 prospectors migrated to the Klondike region of the Yukon to hunt for gold.

But intensive mining in the region has proved one of the major threats to Alaska's salmon population, with chemicals leaching into the streams and soil erosion from open pits clogging up spawning beds.

Salmon Gold, established by the NGO RESOLVE, pairs miners with environmental restoration and conservation workers, to combine mining sites with projects to restore the health of the natural environment.

"There's a lot of tension between mining and salmon," explained Stephen D'Esposito, CEO of RESOLVE. "Salmon Gold is like a peace treaty between mining and salmon habitat. It's a place where the three sectors can work together: the restoration community, First Nations and the mining industry."

Alongside sourcing greener gold, Apple is also taking wider steps to source more recycled metals for its tech products. For example, its new Macbook Air features a motherboard made with 100 percent recycled tin and 100 percent recycled aluminum in the laptop's alloy shell, and is being touted as its "greenest Mac ever."