Sort:  

You start at the back of the list, then climb to the top spot and then you should witness a block and get a reward. This moves you out of the witness-miner queue and you start minign again in order to get included once more in the list. It should normally take between 1 and 2 hours to move to the top spot in the list.

aaah ok, so when i witness a block i get removed the list and i need to find another block again to be added. ok cool thank you!