Documentation 
Section: Aisleriot — Gold Mine — Setup
Empty piles can only be filled by Kings or group of cards starting with a King.

Correct version:
An empty pile in the Tableau can be filled with any card.

Other information:
The documentation has two opposing statements in the same time. In the «Setup» section it says that empty piles can only be filled by Kings, though the actual game allows to do it with any card, just like it is stated few paragraphs later (in «Rules» section).