How to get to caves for Baldy's quest

Hey another question, sorry if it's basic but none of the searches actually addressed my issue which is:

How to get to the caves for Baldy's treasure quest?

The first time I drank the medicine to get there, and at my current point in the game there are actual transitions visible in the map to the caves in both Agroprom and the Dump. The problem is that both points appear to be inaccessible...from reading the walkthru they only get activated once I'm in the cave in the first place? (From talking to the miner there)

Seems to be a chicken/egg problem for me here.

When Baldy gives you the task, transitions into the Caves should appear at the end of the railway tunnels in the Dump and in Agroprom. When you arrive in the Caves, talk to the Miner.

I was looking on the left corner of the tunnel end when the actual transition was on the right corner. I'll have to be more exact next time. Thanks.