However, Ye Liuyun didn't need to worry about these things. Ye Liuyun was surprised when Dong Tianyu proposed to give an information fee, he unexpectedly took out a ton of saltpeter.
Furthermore, he has stated that if the news is accurate and there are a sizable amount of abandoned metals, he is willing to add an extra information fee.
From Dong Tianyu's statement, two things can be analyzed. The first one is that Dong Tianyu has many saltpeter in his hands.
The second point is that, Dong Tianyu not only capable of purifying metals, but also reuse them. Dong Tianyu is not hoarding the metals for the rarity, but for other purpose.
You have to know that since he started trading with Dong Tianyu, he alone has traded a lot of metal ingots, let alone adding other people. (Ye Liuyun didn't know that Dong Tianyu didn't look for other partners.)