Since 1870, there have been several formal attempts to restrict the copper output and raise, in this form, its price.
This is a list of copper cartels in the 20th century:
References
Copper cartels Wikipedia(Text) CC BY-SA
Since 1870, there have been several formal attempts to restrict the copper output and raise, in this form, its price.
This is a list of copper cartels in the 20th century: