As the saying from mid-19th century California goes, during a gold rush the easiest way to get rich is selling shovels and picks. 

The world’s 50 biggest miners gained a combined $42 billion during Q2, but the ranks of lithium stocks in the top tier have halved as valuations plummet.

The fresh investment takes Rio's interest in Sovereign, the owner of Malawi's Kasiya rutile-graphite project, to 19.76%.

Despite gold's price slump, strong copper and iron ore prices lifted MINING.COM's ranking of the world's 50 most valuable miners to a new record high of $1.35 trillion.