SINGAPORE, July 17 (Reuters) - London copper futures bounced back on Tuesday underpinned by low inventories and technical support, but concerns of slowing growth in top metals consumer China limited gains. Three-month copper on the London Metal Exchange was up 0.4 percent at $6,216 a tonne as of 0706 GMT and the most-traded copper contract on the Shanghai Futures Exchange finished down 0.4 percent to 48,810 yuan ($7,307.21) a tonne. INVENTORIES: Headline stocks of copper in LME-registered warehouses gained 1,525 tonnes to 257,200 tonnes, but were still at their lowest since January. MCUSTX-TOTAL SUPPLIES: There was additional support for the copper market stemming from expectations of output disruption. ESCONDIDA: "Copper held up relatively well, as the possibility of supply disruption in Chile was back in the headlines," ANZ said in a note. "Workers at BHP's Escondida copper mine rejected the company's first formal wage offer. The two parties are expected to head back to the negotiating table later this week." TECHNICALS: LME copper is poised to break a resistance at $6,260 per tonne and rise more towards $6,370, as suggested by its wave pattern and a retracement analysis, according to Wang Tao, Reuters analyst for commodities and energy technicals. GROWTH: China's economy expanded at a slower pace in the second quarter as Beijing's efforts to contain debt hurt activity, while June factory output growth weakened to a two-year low in a worrying sign for investment and exporters as a trade war with the United States intensified. TRADE WAR: China's commerce ministry said on Monday it had filed a complaint to the World Trade Organization (WTO) regarding Washington's proposed tariff list on $200 billion worth of Chinese goods on July 16. INVESTORS: Copper speculators switched to a net short position of 12,919 contracts, the Commodity Futures Trading Commission said last week, the weakest position since December 2016. ALUMINIUM SUPPLY: China's aluminium producers are responding to tighter supply conditions by boosting output, data showed. China's June output rose by 0.8 percent to 2.83 million tonnes, which on a daily basis was the highest since June 2017, according to Reuters' calculations based on official data. ZINC: Shanghai zinc futures finished down 2.5 percent and lead dived 2.1 percent on worries over Washington-Beijing trade war curbing demand.