The Aluminum industry in Venezuela is concentrated around Puerto Ordaz and Ciudad Guayana. They have several large plants, and workers are protesting because they haven't received adequate pay raises and for other issues (it seems they also requested that management be fired at one of the plants). In case the reader isn't aware, Venezuela suffers from the highest inflation rate in Latin America, therefore workers get really upset unless they get periodic raises.
http://www.eluniversal.com/2010/04/05/eco_ava_arrecian-protestas-d_05A3693933.shtmlHere'a discussion in Metalminer about the Venezuelan mining industry:
http://agmetalminer.com/2009/09/10/venezuelan-government-cant-keep-its-fingers-out-of-the-metals-sector/This may be a touchy issue in the next few months because the power crisis is leading to a cut in the electricity available for aluminum production, and the workers are a little edgy.