The concept has been around for some time in various fields, including new technology, entertainment and media, and has been relatively successful. As a result, some mining companies have decided to utilise it.
CHART: The gold price may grab headlines, but coal's rally comes as a shocker – thermal prices are up 22% in 2016 and coking coal's back in triple digits.
Fresh off a bounce in the polls, Democratic nominee Hillary Clinton is promising to revitalize Pennsylvania communities hurt by a downturn in the coal and steel industries.