(Updates prices) HANOI, April 1 (Reuters) - London copper prices fell on Thursday to their lowest in nearly a month, hit by a survey showing subdued factory activity growth in top consumer China last month, and as a supply threat in Chile was averted after top producer Codelco struck a wage deal. Three-month copper on the London Metal Exchange fell 0.9% to $8,710 a tonne by 0725 GMT, having dropped to $8,695 a tonne, its lowest since March 5, earlier in the session. The most-traded May copper contract on the Shanghai Futures Exchange closed down 0.8% at 65,090 yuan ($9,906.40) a tonne. China’s factory activity in March expanded at the slowest pace in almost a year on softer overall domestic demand, with the Caixin/Markit Manufacturing Purchasing Managers’ Index (PMI) dropping to 50.6, its lowest since April 2020. “The Chinese Caxin PMI numbers for March ... confirm the slowdown in physical metals demand of late,” Malcolm Freeman, a director at UK broker Kingdom Futures, said in a note. Yangshan copper premium SMM-CUYP-CN hovered around its lowest since Dec. 23 at 58.50 a tonne, indicating weakening demand for imported copper into China. Stockpiles of the metal in exchange warehouses have been rising steadily. MCUSTX-TOTALCU-STX-TOTAL Meanwhile, Chilean state copper giant Codelco clinched a deal with workers at its Radomiro Tomic mine after they accepted a new contract offer, defusing worries about a potential strike. * LME zinc fell 0.9% to $2,793 a tonne and lead declined 0.6% to $1,963 a tonne, while aluminium rose 0.5% to $2,222 a tonne. * ShFE lead dropped 0.8% to 15,230 yuan a tonne and zinc fell 1.1% at 21,405 yuan a tonne, while aluminium rose 1.3% to 17,400 yuan a tonne. * U.S. aluminium premium hit its highest since June 2019 at $416.30 a tonne, while premiums in Europe reached $153.87 a tonne, a level unseen since May 2018. * For the top stories in metals and other news, click or ($1 = 6.5705 yuan) (Reporting by Mai Nguyen; Editing by Rashmi Aich and Subhranshu Sahu)