UPDATE 1-China Oct rare earth exports slump to 3-year low

* China's Oct rare earth exports at 3,100 tonnes -customs * Monthly total is lowest since Sept 2015 -Eikon data * Volatile exports could reach new highs in Dec -analyst (Updates throughout) By Tom Daly BEIJING, Nov 8 (Reuters) - China's exports of rare earths fell by 37.4 percent from the previous month to their lowest in more than three years in October, according to customs figures released on Thursday and Refinitiv Eikon data. The world's largest producer of rare earth minerals, a group of 17 elements used in electric vehicles and consumer electronics, shipped 3,100 tonnes last month, versus 4,950 tonnes in September, the General Administration of Customs said. The exports were down 10.6 percent year-on-year and marked the lowest monthly total since 3,033 tonnes were shipped overseas in September 2015, according to Refinitiv Eikon. "China's rare earth exports are volatile and cyclical, with October being a traditionally slow period for the market as a whole," Ryan Castilloux, managing director of research firm Adamas Intelligence, said by email. China's Ministry of Industry and Information Technology said last month that a low rare earth output quota for the second half of 2018, which sparked fears of supply restrictions, was due to an unusually high quota for the first half. The ministry launched on the same day a one-month nationwide crackdown on illegal rare earth mining in China. China's key export market the United States had in July threatened to slap import tariffs on rare earth elements, as part of a trade dispute between the world's top two economies, before removing them from a revised tariff list published in September. Castilloux noted that exports remain 3 percent higher year-to-date and expects them to "gain a few more points as buyers commence re-stocking before year-end." For January-October, rare earth shipments were up 2.7 percent year-on-year at 43,080 tonnes, customs said. "While October exports are at multi-year low levels, we saw record high export levels in February, June and September of this year that will offset last month's lull," Castilloux said. "We expect December export levels to reach new heights, coming in somewhere between 5,500 to 6,000 tonnes." (Reporting by Tom Daly; Additional reporting by Gavin Maguire in SINGAPORE; Editing by Tom Hogue)