* FTSE 100 down 0.3 pct; down 2.2 pct over quarter
* Babcock nearly recoups last week's losses
* Miners extend gains slightly on China stimulus optimism (Recasts, updates prices, adds fresh quote)
By Tricia Wright
LONDON, March 31 (Reuters) - Babcock was the star performeramong Britain's top shares on Monday as a nuclear contract winhelped it outperform a lacklustre showing on the broaderblue-chip index, which suffered its first quarterly drop sinceJune.
The British benchmark ended down 17.21 points, or0.3 percent, at 6,598.37 points, after a see-saw session whichsaw it trade between 6,583-6,658, leaving it down 2.2 percentfor the year on the last day of the first quarter.
Traders saw Monday's trade as emblematic of the index'storrid start to the year, with concern over the economic impactof tension between Russia and the West, as well as weaker datafrom the United States and China, having knocked sentiment.
"It's been a choppy first quarter anyway and I think there's(been) some rebalancing going on before we go into the secondquarter," Manoj Ladwa, head of trading at TJM Partners, said.
Among bright spots, Babcock rose 4.3 percent inheavy trade after the engineering contractor and its U.S. peerFluor were named preferred bidders for a 14-year, 7billion-pound ($11.7 billion) contract to manage thedecommissioning of Britain's nuclear sites.
The gains on Monday saw the stock almost recoup its lossesfrom last week when Babcock announced a big rights issue to fundthe acquisition of helicopter firm Avincis.
"Positivity in the stock from what I call 'gold-platedgovernment contracts' (on account of both prestige and value)should extend the share price to my six-month target of at least1,550 pence," said Jordan Hiscott, a senior trader at GekkoGlobal Markets. The shares closed on Monday at 1,347 pence.
Trading volume in Babcock stood at 5-1/2 times its 90-daydaily average. Turnover for the British benchmark as a whole was1-1/5 times its daily average.
Mining companies rose 0.3 percent. That tooktheir rally since their March 20 low to around 5.5 percent.
A string of weak economic data from China has led toexpectations the government will try to boost demand in theworld's largest metals consumer. The Chinese premier said lastweek China could act to support infrastructure investment.
But the sector retreated from an intraday peak as copperstalled after earlier hitting a two-week high.
"A bit of a bounce in the sector...just on hopes thatcommodity prices will get a fillip from the Chinese stimulus -although actually metals prices haven't bounced as much as wemight have expected, which I think is why the markets aregenerally just tailing off," said Matt Basi, head of salestrading at CMC Markets.
"Until we've got further clarity on what's going tohappen...it's probably wise for people just to be a bit morecautious and take a bit of money off the table."
Rio Tinto led the miners higher with a 1.8 percentgain, as Credit Suisse reiterated the stock on its "focus" list.
"Potential for shareholder returns at Rio Tinto is largerand could be sooner than any of its peer group including BHP,"analysts at Credit Suisse wrote in a note. (Additional reporting by Alistair Smout)