Maybe it’s not directly advisable to take that spot price, but the futures market gives a slightly better picture (forward curve). However, those [futures and spot] usually move quite hand in hand, but with common sense, the spot market might experience more short-term supply and demand peaks (?):
In the Sotkamo Silver thread, analyst Antti Viljakainen has explained the valuation methods he uses for SoS. This also applies to mining companies in general: