From the paper’s conclusion:
We estimated that the amounts of Fe, Ni, Co, and the PGM present in 1986 DA could exceed the reserves worldwide. Moreover, if 1986 DA is mined and the metals marketed over 50 yr, the annual value of precious metals for this object would be ∼$233 billion.
The graphic to the right, figure 13 from the paper, illustrates the amount of precious metals available in asteroid 1986 DA, compared to the world’s entire reserves (FE=iron, Ni=nickel, Co=cobalt, Cu=copper, PGM=platinum group metals, Au=gold). From this single metal asteroid a mining operation could literally double the metal that had been previously mined on Earth.
In estimating the value of these metals, the paper tries to account for the certain drop in price caused by the flooding of so much material into the market. It is a guess however. What is clear is that this asteroid could easily serve as a supply house not for Earth but for all future colonies in space. While expensive for Earth use, for colonies already in space the material would be relatively easy to reach and mine. The colonies will already have the transportation infrastructure, since they couldn’t exist without rockets and interplanetary spacecraft. And mining and processing this asteroid material will be far easier and cheaper than trying to find it on Mars and then process it.
Asteroid 1986 DA is estimated to be about 1.7 miles across, based on radar data obtained during a close Earth fly-by in 2019. The second asteroid, 2016 ED85, appears to have a similar content from spectroscopy, but no radar data has as yet been obtained of it, so much less is known.