I've been playing this for a while now, (not continuously), and I'm not sure what to do now, or if I've done certain things. I was trying to figure out how to get the Spiffy Cola for the kid, so I was looking through the forums, and someone mentioned a sledgehammer, miner, and the sandstone caverns.
I have mapped out the entirety of the Akumos Mines, (or what I can find), and I have yet to come across sandstone caverns, or I'm not paying enough attention. I'm not sure if I've helped the miner. I don't have a sledgehammer.

Inventory:
2 Nanoxite Stones
Scrap of Paper
Silver Key
Pickaxe
Washcloth

5 Peryolitium Shards
I.D. Card
Gold Key
Wrench
Round Pot

Leather Briefcase
Passcard (CQ20024)
Peryolitium Key
Noise Filter Headset
Small Mirror

Metal Briefcase
Passcard (CQ30021)
Vault Key
Knife
Sleeping Pills

Employment Papers
Passcard (CQ60537)
Dragon Key
ISO Energy Pulse Gun
Rock

ISO Access Form
Supply Room Card
Crowbar
Tranquilizer Gun
Tranquilizer Spray

Violations Report
Mine Access Card
Light Tube
Military Uniform

Beetle Analysis Papers
OSA Card
Radio Receiver
ISO Officer's Cap

Peryolitium Shell Diagrams
Izacladia Access Card
Fire Extinguisher
Pet Snacks

ISO Accident Report
Business Card
Crank
Matches

I know I have put 2 rubber tubes in the kitchen vents, one of which was from the Maintenance tubes. I also know I've given the kitten back to the little girl.
If anyone knows what I should be doing, or if I should have another item, it would be much appreciated. Thanks.