Having lived in China, you have to understand that they have a...

Having lived in China, you have to understand that they have a shortage of electricity. Copper smelters, aluminium smelters and steel makers are cut to 3 - 4 days a week of operation in the winter months. Electricity is needed to keep people warm. I've been in a hotel in winter when they cut the power at 1 am in the morning when it was -15 outside (not so nice). So understand that they buy less in October, November and December - forcing prices down. They over-purchase throughout the rest of the year. Prices of all the commodities that China imports are always up in the New Year with more demand from late January - after Chinese New Year and associated holidays are over. If the price has slipped, it is a normal annual problem. Lithium battery manufacturers will also have their electrical capacity reduced and the demand for manganese will reduce correspondingly.
Demand will outstrip supply before the plant starts. Higher prices than these will be obtained for sure - probably with long-term contracts for offtakes from car manufacturers and lithium battery makers. It will be the only +50 year strategic supply outside of China. A no-brainer. just look at Lynas.