Santa it appears you must be a newbie follower of SLI as you lack considerable knowledge regarding SLI. Rick correct me if I'm wrong, but the development material you refer to came from the adit and shaft in the A4 vein system.

And Santa the adit and shaft on the A4 did not follow any veins nor were they suppose to. The purpose of them both was to acess the veins in the A4

FYI Santa

Adit - A nearly horizontal passage from the surface by which a mine is entered

Shaft - A primary vertical or non-vertical opening through mine strata used for ventilation or drainage and/or for hoisting of personnel or materials; connects the surface with underground workings.