Planned copper mining projects will be unable to support demand growth at current rates and could see the market for mined copper in deficit for most of the next decade, Rio Tinto Ltd. (RTP) said Tuesday.

In slides presented at an industry conference in London, Matthew Holcz, general manager, business development of Rio Tinto Copper, saw production from probable copper mining projects as only able to support annual demand growth of 3% a year by 2020.

If demand for mined copper grows at 5% a year, the market won't go back into surplus by 2020 even if all probable greenfield projects go into production, pushing mined copper output from the current level of around 16 million tons to more than 22 million tons.

Around 80% of global copper consumption comes from mined sources, with the balance made up largely from scrap recycling.

In a report earlier this month, the International Copper Study Group estimated demand for the red metal will rise by 3.81% in 2010 and 4.49% in 2011.

Rio Tinto is one of the world's biggest copper miners, with non-controlling stakes in Escondida in Chile and Grasberg in Indonesia, the world's two largest copper mines, and 100% ownership of the Bingham Canyon mine in Utah, historically one of the world's most productive copper mines.

The company also has stakes in Mongolia's Oyu Tolgoi project, seen as the world's best undeveloped copper-gold project, and Alaska's Pebble prospect, the world's largest undeveloped copper resource.

Holcz said that less than half of the world's copper supply in 2020 will come from low-risk regions, compared to nearly two-thirds in 2000. High-risk regions will account for 9% of global supply, he said.

Ore grades will also continue to decline toward 1% contained copper, although at a slower rate to 2020 than over the past few decades, while major new copper discoveries are increasingly deep below the surface.

Copper is seen as a barometer of global economic health but its rise to the highest levels since July 2008 has come despite renewed concerns around global economic growth.

Analysts believe that the weakening U.S. dollar--which raises the cost of dollar-denominated commodities--concerns about the performance of paper currencies, and expectations of a supply deficit from next year have driven the metal's rise. Three-month copper futures traded on the London Metal Exchange were $8,340/ton at 0015 GMT Wednesday.

Average per person consumption of the metal will rise from around $12 to around $16 by 2020, Rio Tinto estimates. Consumption in developed economies plateaus around the $25-a-head level.

-By David Fickling, Dow Jones Newswires; +61 2 8272 4689; david.fickling@dowjones.com