12/31/2011 01:36 EST | Updated 03/01/2012 05:12 EST

Last ditch talks break off at Rio Tinto Alcan's Alma, Que., smelter

ALMA, Que. - Last-ditch talks collapsed today between Rio Tinto Alcan and workers at the company's smelter in Alma, Que.

The breakdown in negotiations increases the chances of a labour disruption -- that could happen as early as Sunday.

On Friday workers from three negotiating units voted down what the company called its final offer.

The union says talks resumed at 9 a.m. this morning but quickly broke down.

Union officials already have a strike mandate in hand and are warning that a work stoppage could be imminent.

The Alma facility hosts one of the company's (NYSE:RIO) most important North American aluminum smelters, with about 800 employees.