* U.S. Q2 GDP, non-farm payrolls scheduled for this week
* Zinc retreats after hitting 3-year high
* Lead slips after 17-month high (Recasts, adds closing prices/details)
By Harpreet Bhal
LONDON, July 29 (Reuters) - Copper prices slipped on Tuesday, as prospects of growing supplies overshadowed encouraging signs of health in the global economy, and zinc retreated after hovering near three-year highs on expectations of a tightening market.
Three-month copper <CMCU3 on the London Metal Exchange (LME) closed down 0.56 percent at $7,080 a tonne.
Data earlier this month showed manufacturing in the world's top metals user, China, expanded at its fastest in 18 months in July, while the U.S. economy has gathered pace, with the outlook for its labour market brightening.
The copper market was expected to register another year of surplus this year, in a move that is seen weighing on prices. Late last week, the world's top copper producer Freeport-McMoRan Inc clinched a deal with the Indonesian government to allow the miner to resume copper concentrate exports.
The base metals complex could struggle to eke out significant gains for the remainder of the week ahead of economic indicators due later in the week and international political risk, analysts said.
This week, second-quarter economic growth in the United States, a U.S. jobs report and an official reading on China's factory health were expected to show fresh signs that a global economic revival has taken hold.
"Investors surely want to wait for the big events.. such as the outcome of the FOMC (Federal Open Market Committee) and the U.S non-farm payroll data this week. No one wants to bet big," said Naeem Aslam, chief market analyst at Ava Trade.
"On top of that Russian sanctions are very much back on the forefront, and the new sanctions by the European Union, which could be announced as soon as tomorrow, are also weighing on the sentiment."
EU diplomats will try to agree on Tuesday on broader economic sanctions against Russia for its actions in Ukraine. Measures being considered include targeting capital markets, defence and sensitive technology.
In the U.S. consumer confidence jumped in July to a monthly high not seen since October 2007, according to a private sector report released earlier.
Benchmark zinc traded at a session peak of $2,416 a tonne, hitting its highest since August 2011 for a second consecutive day, but ended down nearly 2 percent at $2,366 a tonne.
Several top zinc mines are drying up, including Century in Australia, while a recovery in the construction industry would revive demand from galvanisers.
"The direction is right. It's probably gone a lot quicker than I expected, which opens it up for some profit-taking ... I wouldn't expect to see a significant sell-off," said ANZ strategist Daniel Hynes in Sydney.
Lead rose to $2,307, the highest since late February 2013, but ended down nearly 1.5 percent at $2,267 a tonne.
Tin ended at $22,900 a tonne, up 1.10 percent, aluminium closed at $1,982 a tonne, down 1.59 percent while nickel ended at $18,650 a tonne, down 0.80 percent.
Goldman Sachs Group Inc's metals warehousing unit is exploring its first foray into China and privately held C Steinweg has expanded capacity there, sources said, as a financing scandal in a major Chinese port fuels a scramble for market share.
Three month LME copper
Most active ShFE copper
Three month LME aluminium
Most active ShFE aluminium
Three month LME zinc
Most active ShFE zinc
Three month LME lead
Most active ShFE lead
Three month LME nickel
Three month LME tin
Additional reporting by Melanie Burton in Sydney; editing by Keiron Henderson and Jason Neely