Mining giant is eying the 32% interest in SQM that PotashCorp is selling to fulfill China's regulators condition for the approval of the its friendly merger with smaller rival Agrium.
Aggregate market cap of the top 100 junior mining companies was up 7% to $12.2 billion, a level not seen since 2010, but the group significantly underperformed the Venture Exchange as a whole.
Prices for cobalt metal, used in production of electric vehicle batteries, have tripled to nine-year peaks above $30 a pound from below $10 a pound in late 2015.