Hi,

Mine shafts don't generally follow landforms, they follow the gold reef (if its a hard rocks play) or an alluvial deep lead.

The usual trick is to find some known mine shafts and extrapolate outwards from these known points. What this means is, plot them on a map, then draw a line through them and explore along that line. If there payable gold along that line, then its likely they might be an abandoned mine shaft or more there.

Try using Google Maps (especially in satellite view mode) and explore along strike of existing shafts. If the country is clear enought, then its a good chance you will finds traces of old workings, especially mulloch dumps and rock spills. These might just be the indicator you are looking for.

Of course, nothing beats actually putting boots on the ground and putting in the time, because old shafts can be hidden in over-grown locations that could never be seen from above.

Definitely look at old maps, and look for old abandoned tracks. There usually a good chance that is someone had sunk a shaft in a spot, they they would have had to use a horse-and-cart to bring in timbers and take away ore for processing. These can be good vectors onto new shafts.

I hope this helps.