* Mounting stocks cast shadow over copper prices
* Nickel prices likely to fall on improved supply in H2 - Citi
* Coming up: U.S. durable goods for July at 1230 GMT (Adds comment, detail; updates prices)
By Melanie Burton
MELBOURNE, Aug 25 (Reuters) - London copper hovered near a two-month low on Thursday on evidence of mounting supply while nickel weakened after lower shipments to China as markets marked time ahead of a key meeting of central bankers.
The dollar was range-bound as major currencies continued to tread water ahead of the global central bankers' gathering in Jackson Hole, Wyoming, at which Federal Reserve Chair Janet Yellen may offer new clues on U.S. monetary policy.
Three-month copper on the London Metal Exchange was little changed at $4,637 a tonne at 0727 GMT, following 1.7-percent loss in the previous session, when it fell to its weakest since July 24.
Shanghai Futures Exchange copper slipped 1.2 percent, paring an early loss of 2 percent, to 36,370 yuan ($5,465) a tonne.
LME copper stocks jumped by 14,625 tonnes, the latest data showed, bringing total stocks above 250,000 tonnes for the first time since November 2015. Stocks have shot up by a fifth in the last week alone. MCUSTX-TOTAL
Meanwhile, China's imports of nickel and zinc slumped on the month in July, while its copper imports slipped by 3 percent, partially due to seasonal factors with many factories closing over the northern hemisphere summer.
LME nickel extended declines by 1 percent to $9,880 a tonne, hitting the weakest since July 11 at $9,860. Heavy losses were also seen in ShFE nickel down 3.3 percent as fears fade over a wholesale halt to Philippine ore exports.
"Despite the closure of eight small-scale producers so far, we could see imports stabilise, belying any concerns of supply constriction from the Philippines that has recently riled markets artificially boosting nickel prices," Citi said in a note.
Elsewhere, Glencore said it expected to exceed a previous target to cut debt, but it took a nearly $400 million hit from a bad bet on coal and echoed warnings voiced by mining rivals of volatile commodity markets.
Russian aluminium giant Rusal on Thursday reported a nearly 40-percent drop in second-quarter core earnings due to weak aluminium prices, slightly better than analysts feared, and warned the second half of the year would remain tough.
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
Most active ShFE nickel
Three month LME tin
Most active ShFE tin
$1 = 6.6554 Chinese yuan Reporting by Melanie Burton; Editing by Joseph Radford and Sherry Jacob-Phillips