LONDON/HANOI, Sept 16 (Reuters) - Hong Kong-listed China Daye Non-Ferrous Metals Mining said on Monday a fire at its copper facilities in China caused a stoppage, which three sources with direct knowledge of the matter said would last for three months.

China Daye Non-Ferrous Metals Mining Ltd did not respond to a Reuters request for comment on Monday on the length of its shutdown or the cause of the fire.

The stoppage could mean the release of copper raw materials to the market, which has faced unprecedented shortages this year.

The fire at the Daye operations in China's central Hubei province broke out on Saturday at its sulphuric acid facility, said the sources, who declined to be named.

Sulphuric acid production is an integral part of the copper smelting process, sales of which contribute to smelters' revenues.

Although primary smelting would be shut, Daye's refinery will remain in partial operation to produce copper cathodes using intermediate products like scrap and blister, the sources said.

Daye, a subsidiary of China Nonferrous Mining Corp , said on Monday it expected to produce 680,000 metric tons of copper cathode this year after taking account of the impact of the fire.

In March, the company said it was targeting output of 870,000 tons of copper cathode.

Fundamentals along the copper supply chain are increasingly polarised, with mined copper concentrates facing shortages due to rapid expansion of global smelting capacity.

Meanwhile copper cathodes, a more refined form of copper for making cables and wires, are facing a surplus due to lacklustre demand from top buyer China.

(Reporting by Julian Luk in London; additional reporting by Mai Nguyen in Hanoi; Editing by Ros Russell)

((julian.luk@thomsonreuters.com; Reuters Messaging: julian.luk.thomsonreuters.com@reuters.net))