The reason it scans all around is because just because you dug a tunnel doesn’t change where the sample comes from. I will increase the sample count based on quality a bit further, so you see easier that you are close to an Ore. For the direction you need to dig tunnels and hammer until you dont find a sample of said Ore anymore.
And prospecting isn’t really supposed to be for small Ores, so I might change that too to only detect big Ores.