"One potential snag is the fact that the majority of the world's cobalt is a byproduct of some other metal mining. In 2017, about 69 percent of the world's cobalt was mined as a copper byproduct and 29 percent as a nickel byproduct."

https://www.cnbc.com/2018/07/09/automakers-and-tech-firms-are-scrambling-for-cobalt.html