A Stardew Valley scouting tip will save you time in the mines - and maybe even other areas of the game - when you're playing on PC.
As far as secret techniques for seeing far beyond your normal field of go view, it's almost distressingly simple to execute. Reddit user hauzan2112 posted a walkthrough video of how the trick works, and it uses a tool that you may never have even realized you have at your disposal. I don't mean an extra piece of equipment, I mean the in-game screenshot tool. Don't feel too bad if you weren't even aware this tool existed - it's buried way at the bottom of Stardew Valley's extensive options menu, and it is its own separate function from using the Steam overlay's screenshots or just hitting Print Screen and pasting your image elsewhere.
As hauzan2112 demonstrates, you can head into an unexplored level of the mines, use the screenshot tool to grab a shot, then open up the screenshot to get a complete, uninterrupted bird's eye view of that level (make sure your screenshot tool is set to the smallest setting, which it should be by default). You can then use the screenshot to scout around the floor and see what kinds of ore and equipment are ready to be harvested - saving you time if you're on a dud floor and just want to head to the next one ASAP, or helping you catch some goodies you may have missed otherwise. If you're playing on mobile, pinching to zoom then panning around can have a similar effect.
You can also use the screenshot tool to capture some lovely views of your entire farm or the entirety of Pelican Town itself. It's a novel way to appreciate Stardew Valley's pixel art pastoralism when you aren't busy making the most of your mine runs, and the final image isn't all that large so it's perfect for sharing on social media if you want to show off your in-game progress.