LONDON, Jan 10 (Reuters) – Nickel broke through key technical levels to reach its highest since 2015 on Wednesday as a sharply weaker dollar helped push dollar-denominated industrial metals broadly higher by making them cheaper for users of other currencies. “The whole industrial metals complex is being supported by a weaker dollar,” said ING analyst Warren Patterson. NICKEL: Benchmark nickel on the London Metal Exchange closed up 1.9 percent at $12,935 a tonne after touching $13,200, the highest since June 2015. TECHNICALS: Nickel, used to make stainless steel, burst above a long-term downtrend line from 2011 at around $12,800 and resistance at $13,000, triggering technical buying, traders said. SUPPLY: Traders said reports of production outages at nickel mines in the Zambales region of the Philippines, a major exporter, could be helping drive prices higher. PREMIUMS: Metal Bulletin reported that reduced availability pushed nickel uncut cathodes premiums in Rotterdam to an 11-year high, but this was unlikely to have caused significant change to the LME price, said Societe Generale analyst Robin Bhar. POSITIONING: Funds have ramped up bets on higher prices, doubling their net long position in LME nickel from a low in December to 29,746 contracts by Jan. 9. DOLLAR: Metals were boosted by a fall in the dollar against a basket of currencies after a report that China was ready to slow or halt its U.S. treasury purchases. GLOBAL GROWTH: Expectations of healthy demand for metals were bolstered after the World Bank forecast global economic growth of 3.1 percent in 2018, up from 3 percent last year. LEAD WARRANTS: Two large warrant holdings fuelled concern over the immediate availability of lead on the LME. Exchange data showed one entity held between 30 and 39 percent of warrants and another between 40 and 49 percent of warrants. LEAD PREMIUM: The shortest time spread on lead, tom/next CMCUT-0, which r epresents the premium to roll over a position for a day, soared to a high of $10 a tonne from $1.50 a day earlier. LME Lead ended up 0.2 percent at $2,550 a tonne. ZINC STOCKS: On-warrant zinc stocks available to the market at LME-registered warehouses fell to 129,300 tonnes after 9,950 tonnes of cancellations, supporting prices. On-warrant inventories have fallen by around 35,000 tonnes this month, helping zinc rise to its highest in more than a decade on Tuesday. LME zinc finished flat at $3,336. OTHER METALS: Copper closed 0.7 percent higher at $7,153.