Blackwater Bandit’s Key Fragment is a part of Fallout 76 Key to the Past
Check the Terminal at Blackwater Mine Walkthrough
To obtain the first key fragment you need to look for the body of Freddie Lang inside the Blackwater Mine. Head to the mine, which is located east of Whitespring Resort. The outside of the mine is likely to be guarded by some Miner Moles (and occasionally even a high level Glowing Miner Mole). They can be avoided by simply running into the mine, but if you want to loot the area you will probably have to clear them out.
Once inside the mine you can grab some quick loot from the rooms to your immediate left and right. There is a bobby pin box in the office on the left, and if you use the stairs to get on top of the office there is a safe that can be lockpicked. Once you are ready to explore the mine follow the train tracks down the shaft. You will encounter some Radrats in a junk filled room.
Once past that room you will find a split path. Heading forward will take you across a rads riddled bridge to a dead end and some more Mole Miners. There is some minor loot you can get in the dead end, and there are also some workbenches you can use to scrap any random items if you need it.