To log a find here you must fulfil the following conditions
1. Sign the log
2. Have found at least 20 caches with the Abandoned Structure attribute
3. Have found at least 2 caches with the Abandoned Mines attribute
You may sign the log before you fulfil the other two conditions, logging a note, but please don't post a Found It log until you have fulfilled all three conditions.
You can either list your qualifying caches, or I can just look at your Project Geocaching profile. If you prefere not to make your stats page there public, you can post a screen shot of that part of the page with your total caches showing.