There was a post on Metals stocks on 27 Nov'18 by Bloomberg over this link
https://www.bloombergquint.com/charts/metal-stocks-are-the-cheapest-in-more-than-five-years#gs.38dOeWQ
Taking the below image from the article as a reference

And adding to it the price analysis to get more clarity as to how the stocks have behaved to this Cheap valuation framework

In Short - When the Metal stocks are most expensive via PE parameter, they are at the bottom prices.