What is the refutation to the disbeliever's claim that building Dhul-Qarnayn's dam was impossible due to the inability to collect and melt the required quantities of iron and copper in that era?

The lack of knowledge regarding the method of collecting and melting iron and copper to build Dhul-Qarnayn's dam does not mean it was impossible, especially if Dhul-Qarnayn was a prophet or a righteous king supported by a miracle or a divine favor. Historians like Ibn Kathir and Ibn Hajar mentioned the difference of opinion among scholars regarding his prophethood or righteousness. Extraordinary feats are not to be ruled out, as Allah softened iron for David (peace be upon him) and caused a flow of molten copper (qitr) for Solomon (peace be upon him), as mentioned in the Quran. It is sufficient that Allah Almighty established Dhul-Qarnayn in the earth and gave him the means to everything, meaning knowledge, or reach, or whatever kings need.