> I have been to the sandstone caverns but now I can't locate them. I have tried to draw a map, but am having a hard time even doing that. Also, I think I need to find a sledgehammer but haven't so far.
>
> Inventory:
>
>
> 2 Nanoxite Stones
> Passcard (CQ60537)
> Crowbar
> Pickaxe
> Plastic Cup
>
> Leather Briefcase
> Supply Room Card
> Light Tube
> Noise Filter Headset
> Round Pot
>
> Metal Briefcase
> Mine Access Card
> Radio Receiver
> ISO Officer's Cap
> Small Mirror
>
> Employment Papers
> OSA Card
> Fire Extinguisher
> Pet Snacks
>
> I.D. Card
> Business Card
> Crank
> Matches
>
> Passcard (CQ30021)
> Gold Key
> Metal Rod
> Washcloth
>
> I can't seem to do anything else on Corolis and I'm going in circles in the mines. I believe I need the sledgehammer to knock something down in order to advance but I can't find it.

The sandstone caverns are reached only by jumping and catching up with the mine cart along the central railway (where you have to jump to avoid being killed entering a low tunnel).

The main thing to do to advance is the third job (OSM Tube) on the Corolis. You have everything you need -- you have to use the Emergency Access Switches to change which doors along the OSM Tube can be opened. It just switches back and forth between two states, so after you find out which doors along a certain section of tube can be opened, hit the nearby Emergency Access Switch once (and just once), then try the doors again.