As far as I can remember you have to throw a scarab coin on the coal basin, not use it.
0 {ScarabCoin} Map.Thrown(3041, 1, X, Y, Z)
X = coordinate X of coal basin
Y = coordinate Y of coal basin
Z = coordinate Z of coal basin
Now copy this macro to Advanced Tools -> Macros
While standing on the blue flame, go to Cavebot -> Codes/Labels -> Macro -> Choose Scarab Coin
0 {ScarabCoin} Map.Thrown(3041, 1, X, Y, Z)
X = coordinate X of coal basin
Y = coordinate Y of coal basin
Z = coordinate Z of coal basin
Now copy this macro to Advanced Tools -> Macros
While standing on the blue flame, go to Cavebot -> Codes/Labels -> Macro -> Choose Scarab Coin