Lead had a more dynamic month in December, hitting a six-year high of $2586/t, before falling back to close the month 0.5% down on where it started at $2491/t. Concerns are deepening that the tight supply picture could become acute in the event of sudden severe weather triggering a high demand for replacement batteries. This could trigger a sharp price rally capable of surging well past December's high point. Glencore's announcement of a phased reintroduction of mothballed mine capacity took a cautious path and helped maintained composure in the markets. Producers and consumers are still mostly locked in battle over prices for long-term refined metal supply in 2018, with smelters currently edging a slight advantage. Indicative treatment charges are little changed in December but negative TCs were traded for more complex material.