Here is the explanatory text from the campaign's page:
Canada/Brazil: Tell Vale that divide-and-conquer won't work
Since being privatized in 1997, the global mining giant Vale has unleashed a vicious attack on workers. The company undermined health and safety standards in Brazil and now it's set its sights on Canada. In 2009 negotiations with the United Steelworkers (USW), Vale claimed it needed deep concessions - despite making over $13 billion (USD) in 2008 net profits. The company’s strategy is to divide and conquer by undermining seniority and providing lesser benefits to new employees. 3,500 members of the USW rejected Vale’s demands and went on strike in mid-July. Vale has since announced it will hire replacement workers and force other union members to do the work of the striking miners. Meanwhile Vale workers throughout Brazil are struggling to hold on to jobs, earn a living wage, achieve minimum standards for safe working conditions, and guarantee basic labor rights. Vale employees and their unions in Brazil and Canada are fighting back together, reaching out to workers in a global campaign for fair treatment at Vale.
Reliable, enduring relations of solidarity across such great physical and social distances are not built overnight, and I would not be surprised to learn that much work remains to be done on that front by Vale employees and the organizations that represent them. Nonetheless, I think it is important to send a pro-worker message to the company, and to show support for those forces within the USW and in the broader labour movement that are working to build global solidarity among workers. Send your email!