The base metals mostly posted slight gains on Wednesday. Copper was at the low end of a 4-cent range for most of the day, until a late morning rally pushed it into the black, with a finish at $3.1402/lb., up more than 2¾ cents.

Nickel was tightly traded within a 15-cent range for the second straight day, closing about in the middle at $8.3552/lb., down 3½ cents. Zinc featured a modest uptrend, ending at its intraday high of $0.7787/lb., up a penny. Aluminum also fared well, rebounding from a mid-morning selloff to nearly regain its intraday high at $1.1671/lb., up a penny and a quarter, while lead edged slightly higher at $0.8052/lb., up a third of a cent.

Copper managed a positive finish for the first time in five sessions as supply concerns ruled the day.

A magnitude 5.8 earthquake hit Chile’s far north, near the country’s largest copper mining areas, and whenever that happens traders tend to get nervous.

However, the big Collahuasi mine, jointly owned by Xstrata Copper (XTA) and Anglo American was apparently spared. “The mine was not affected at all,” said Hernan Farias, a union leader at Collahuasi. “Operations are running normally.”

Analysts also noted that there was a good measure of short covering in copper yesterday.

In company news, Freeport-McMoRan Copper & Gold (FCX) said it expects recent lower copper prices to result in a $100 million reduction in its third-quarter net income. At the same time, the company announced a reduced 2008 copper production outlook, due to problems at its flagship Grasberg mine in Indonesia.

Freeport said that initial estimates indicate about 150 million pounds of copper and 200,000 ounces of gold previously expected to be mined in 2008 will be deferred to future periods.

But, “Whatever they (Freeport) announce right now I don’t believe will have any dramatic impact on prices unless or until we see an impact on the global fundamentals,” said John Gross, publisher of the Copper Journal.

Source: Base metals steady - Chile quake supports copper.