This is an image of ‘OPEN CUT’ which many miners used to find quality opals decades ago. The mining has been carried out mainly by ‘hand’, except for the early stage, drilling part.
The modern mining style won't be the same, it's done narrowly down side and an automatic dump hoist will bring the soil & the dirt straight up.
Dig down really deep but not too far (no more than 20m from the ground level), as the soil is considered to be too wet - meaning opals seem to contain too much moisture which will cause natural cracks.
Once you have reached the ‘opal bed’, then dig more soil & dirt side way.
Unlike ‘white opal’, Lightning Ridge black opal don't come in a large size. When you hit the ‘spot’ then one must carefully slow down the work and hand dig.
Looking for the ‘NOBBY’ or the ‘SEAM’ opal often hidden in the sandstone or the sandclay.
This is an image of ‘Seam Opal’ but hardly any quality piece can be found from this...