Mines1337 does not collect any personal data.
The app does not communicate with any server. The puzzles are generated locally on the device. Game states are saved locally on the device only. It is possible that app settings and game scores are saved in iCloud if you have iCloud backups enabled.
The app does not communicate with any third parties. Not for user tracking, not for advertising. The app does not contain advertisements, there is no connection to game center, and there are no in-app-purchases. It is a pure offline-app, and it also works well in flight-mode.
Document version 1, on 8th January 2018
A German version is available too.