What metadata can be captured by a single miner? What about a group of miners? It is my understanding that the blockchain consist of the following information for every transaction in the network:


From address
To address
Amount of bitcoins


What additional information can a miner collect? For example, is it easy to find the IP address that the transaction was first sent from? Is there other identifying information a single or group of miners can capture? What roll do bitcoin tumblers play in all this?
The sender, recipient and transferred amount are already public information and readily available in the blockchain.

The only special access that miners have is that they could log the ip address of users that directly submit transactions for mining, if such a direct access is offered. Besides that there is no special information available to miners.