If this comes to fruition it would have a considerable impact on metal markets. A city that covers over 10K square miles and 33 times the size of NYC. Maybe just a dream, and certainly cant be built over night, but just the start up should increase the demand for certain metals, including copper.
https://www.bloomberg.com/news/articles/2017-10-24/saudi-arabia-to-build-new-mega-city-on-country-s-north-coast