LONDON, Mar 22, 2011 (Dow Jones Commodities News via Comtex) -- (Adds details on regional demand in the 3rd-5th paragraphs; details on supply, including mine production in the 7th-9th paragraphs.)

The world refined copper market was in deficit by about 305,000 metric tons in 2010, the International Copper Study Group said in its preliminary full-year data Tuesday.

The market plunged into deficit, following a surplus of 175,000 tons in 2009, on stronger-than-anticipated refined copper usage, coupled with a smaller-than-anticipated growth in supply.

In 2010, world demand for refined copper grew by around 7% to 19.356 million tons as it recovered from weak 2009 usage levels in the European Union, Japan, and the U.S. Demand last year was up 8% in both the European Union and U.S., while it rose a massive 20% in Japan, the figures showed.

"Although these year-on-year growth rates are strong, usage in the European Union, Japan and the U.S. remained well below pre-crisis levels," it said.

Chinese apparent usage also increased, but by a more modest 4.3%, from the very strong apparent usage growth of 37% in 2009.

World refined production in 2010 meanwhile increased by 4%, to 19.049 million tons, after higher output in China, Japan and the European Union, the ICSG said.

Production from the two other major world refining countries, Chile and the U.S.--which together account for about one quarter of world production--fell by a combined 2.2%.

World mine production increased by just 1%, to 16.1 million tons, the data showed.

"Post-crises cutbacks, operational failures, labor unrest, and lower ore grades resulted in production levels not keeping pace with the growth of capacity," the research group said.