Description
Copper was the first metal to be mastered by mankind and was used for making bells, cauldrons, tools and utensils in the prehistoric era. Copper has excellent ductility, thermal conductivity and electrical conductivity. Copper and its striations are both copper red in color. Extended exposure to moisture triggers a chemical reaction that makes the surface layer turn a dark brown. A green patina of copper patina referred to as "verdigris" then gradually forms over time. Native copper oxidizes easily into copper oxides or carbonates, forming secondary minerals such as cuprite, malachite and azurite. Native copper is relatively rare in nature and most copper in use today is smelted from copper sulfides and is used in the electrical industry, currency and decoration.
In Taiwan copper is mainly found in the Jinguashih mining district as well as Porphyry Copper and copper-bearing iron sulfide deposits in eastern Taiwan.

Mineral Formation
Copper is mainly formed in copper sulfide veins subjected to alteration and is often found co-existing with cuprite, azurite and malachite.

Geographic Distribution
(1) The Jinguashih mining district.
(2) Porphyry copper deposits in Hualien Cimei region, Taitung's Jhangyuan region and the Doulan mountains.
(3) Copper-bearing iron sulfide deposits at Tongshan, Dong-ao and Taibaishan in Yilan, Tongmen and Rueisuei in Hualien as well as Dejyue in Taitung. 

Mining History
Copper mining commenced in Taiwan the year after enargite ore was found in the Jinguashih mining district in 1905. Production continued to increase and reached 1,875 tonnes in 1914.

Japan stepped up its mining efforts during World War II and copper became an important strategic material. After the liberation mining operations at Jinguashih were taken over by the "Taiwan Gold and Copper Mining Administration" (TGCMA) set up in 1946. The TGCMA became the "Taiwan Metal Mining Company" in 1955 and with gold production on the decline while copper production continued to increase, Taiwan Metal became the largest copper mining company in Taiwan. In 1981 the Taiwan Metal commissioned the "Lile Copper Smelter" near Shueinandong capable of producing 50,000 tonnes of electrolytic copper and 175,000 tonnes of hydrochloric acid a year. Continued drops in the international copper prices however forced Taiwan Metal to transfer the Lile copper smelter to TaiPower in 1985. Taiwan Metal itself shut down in 1987. In January, 1990 a break in metal piping led to a massive leak of hydrochloric acid from the storage vats at Lile Copper Smelter. The government immediately ordered a suspension of all operations and in June of the same year TaiPower shut down the Lile Copper Smelter, bringing an end to the Taiwanese copper industry.

Most of the copper ore in eastern Taiwan are in the form of "porphyry copper" and "copper-bearing iron sulfides". Cimei is the most important source of porphyry copper with the first discovery made in 1903. This was the first copper mining area in Taiwan and small-scale mining was carried out by the Rueiyang Metal Mining Company here after the Liberation. Minerals found in copper-bearing iron sulfide deposits include chalcopyrite, pyrite, sphalerite and galena. Most of the deposits are located in the Tananao Schist along the eastern slopes of the Central Range including Tongshan and Dong-ao in Yilan as well as Tongmen in Hualien. The Japanese began surveying Tongshan in Yilan as early as 1917 and after the liberation the mine was nationalized. Mining rights were licensed to the Fongyuan Mining Company, then the second largest copper mining company in Taiwan. No copper mining is currently carried out in Taiwan.

Production
The Jinguashih mining district produced 47 tonnes of copper ore in 1907 with production peaking at 6,955 tonnes in 1937. At the Tongshan mining district in Yilan, the Fongyuan Mining Company produced a total of 2,197 tonnes of copper between 1963 and 1980. (L.P Tan and J.S. Wei, 1997)

Applications
Copper is mainly used in the electrical and electronics industry for cables, wiring and electronic parts. It is also used in machinery manufacture, chemical engineering, construction, transportation, currency and decorations.

National Museum of Natural Science