[colorado tanker]

Any American who wins anything is liable for tax on the winnings.

What I have read regarding the Olympic medals is they are taxed at the value of the materials, not what an auction might fetch.

[lacrew]

Material is worth at most 600 bucks:

http://ftw.usatoday.com/2016/08/how-much-is-an-olympic-gold-medal-worth-cost-sell-gold-prices

The tax haul comes from the cash award.