The country's mining exports last month were the highest since 2014.
A memorandum of understanding between the two countries will promote investment in mining while improving environmental and social sustainability.
The total gross debt of Brazilian steelmakers Gerdau and Usiminas was nearly US$9bn at the end of June.
Chile's mining industry has been a champion in the use of seawater for its processes. Several mines already use seawater directly or desalinated, and there are several new desalination plants expected to be built in coming years.