(CNN) -- On Oyu Tolgoi -- "Turquoise Hill" -- the biggest business venture in Mongolia is taking shape.
The copper resources aren't new to locals -- after all, for thousands of years locals dug out copper to melt down into things like arrowheads, CNN's Stan Grant reports.
But the massive Gobi Desert copper and gold mine -- a joint venture with foreign mining conglomerates Ivanhoe and Rio Tinto -- is expected to account for one-third of the nation's total economic output by 2020 and boost the average earnings of Mongolia by 60%.
The numbers are staggering. The development phase runs to nearly $5 billion. The mine is projected to produce to 450,000 tons of copper and more than 300,000 ounces of gold. Developers claim there's enough here to mine for the next 50 years or more.
Yet it's placing stress on an ancient nomadic way of life.
Many locals they're worried the mine will drain all the water, although mine owners say Oyu Tolgoi has a separate underground source.
There is also stress on animal herds and available land.
Says one nomadic herder: "At the moment it's impossible to graze our herd near the mine. Officials might say it is only 10-kilometer limit, but because of the traffic and dust you don't see any herds within 20 or 30 kilometers."
Other herders, like Myagmarjav, say they are benefiting from extra money for his wife and children through part-time work at the mine.
"We think we can work at the mine and take care of our herds. My three children will get a chance to go to school and have a better education," he says.