POLL-Growing supply bears down on 2014 copper prices
* 2013 cash copper seen at $7,334.90/T in 2013; $7,050 in 2014
* Copper surplus seen at 182,000 T in 2013; 328,000 T in 2014
* Tin, lead seen ending the year higher due to deficit market
* Click on for a full range of forecasts
LONDON, Oct 24 (Reuters) - Copper is expected to end the year 8 percent lower, and tumble further in 2014 as demand struggles against strong supply growth from new and existing mines, a Reuters poll showed.
The average forecast for 2013 cash copper prices from 26 market participants surveyed dipped to $7,334.90 a tonne, from a forecast of $7,315.70 in a July poll, and down 8 percent from the 2012 average price of $7,958.33.
For 2014, analysts cut forecasts for the metal used in power and construction to $7,050 per tonne, from a previous forecast of $7,140.
Ramped-up output has dimmed the outlook for copper and eroded its appeal among investors. At a current price of $7,180 a tonne, benchmark three-month copper is trading more than 9 percent lower in the year-to-date.
"Mine supply is growing at the strongest pace in almost a decade and there have been limited disruptions," said Gayle Berry, analyst at Barclays.
"We expect that surplus to widen into 2014, leading to stock increases and new lows for prices."
Highlighting the outlook for increased supply, BHP Billiton , the world's biggest mining company, said it produced 6 percent more copper in the quarter to end-September than in the year-earlier period.
The market is also bracing for more supply from Rio Tinto's giant Oyu Tolgoi mine in Mongolia after news that a customs dispute which had been holding up copper concentrate shipments has been resolved.
Analysts expect the copper market to post a surplus of 182,000 tonnes this year, up from a previous forecast of 153,000 tonnes before ballooning to 328,000 tonnes in 2014.
Tempering concerns about oversupply were signs that demand from top consumer China was improving after data showed refined copper imports surged 32 percent month-on-month in September to reach a 19-month high.
China accounts for roughly 40 percent of global refined copper demand.
China's economy grew at its quickest pace this year between July and September, but analysts said signs are emerging that the pick-up in activity may lose some momentum and result in a slower pace of consumption of commodities such as copper.
<^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ For a graphic on the base metals poll 2013/14: http://link.reuters.com/vem45t
Analysts expect the oversupply in the aluminium market to shrink from 853,000 tonnes this year to 591,746.6 tonnes in 2014. Next year's surplus forecast compares with a surplus of 1 million tonnes for 2014 predicted in a previous poll.
"Thanks to the combination of output cutbacks by western companies and anticipated clampdown on overcapacity in China, there is a realistic prospect that the aluminium market will eventually shift from surplus to deficit over the coming two years," Natixis analysts said in a note.
The surplus, however, is still seen weighing on aluminium prices, which 21 analysts expect to average at $1,873.6 a tonne this year, down from a previous forecast of $1,907.50 and 7 percent lower than $2,021.6 in 2012.
Prices are expected to rise slightly to $1,885 a tonne in 2014.
The biggest gainer for the year is expected to be tin , which is seen averaging $22,075 a tonne this year, up 5 percent from 2012 prices, and rising further to $22,797.50 a tonne in 2014.
The bullish outlook for tin stems from a deficit market and new trading rules from the world's biggest exporter Indonesia which has cut shipments from the country by nearly 90 percent.
Lead is also seen as a gainer, with prices expected to end the year 4 percent higher at $2,151.40 a tonne and climb to $2,264 a tonne in 2014, as the market is seen moving from a surplus of 15,500 tonnes this year to a deficit of 26,000 in 2014.
A surplus market in nickel and zinc is expected to weigh on prices for the metals for the next two years. Nickel is seen averaging at $15,152.80 a tonne, down nearly 14 percent on the year, and is expected to average at $15,367.50 a tonne in 2014.
Zinc is expected to end the year 1 percent lower at $1,921.50, before recovering to $2,012.50 a tonne in the following year.
(Additional reporting by Arpan Daniel Varghese and Nallur Sethuraman in Bangalore; editing by Veronica Brown and James Jukwey)