What are the rules at this site that govern this decision ?
They seem inconsistent. I've had games end when 1 side had several minor pieces left but also games wherein 1 side only had a king but play continued.
In both situations the game will only end when either side runs out of time or checkmate/stalemate occurs/3 fold repetition occurs and is claimed or 50 move rule applies and is claimed. Which happened in your case ?
An automatic end to the game while both players have time remaining will only occur if neither player is capable of delivering mate (eg. K vs K)
On a timeout the player who has time remaining will win unless he does not possess sufficient mating material on the board in which case it is a draw (eg K +B vs K +N)
Please link to the game where you are not understanding the rules.
What are the rules at this site that govern this decision ?
They seem inconsistent. I've had games end when 1 side had several minor pieces left but also games wherein 1 side only had a king but play continued.