We've searched the internet and found the largest collection of On30 Scale trains for sale is on eBay. Below are the listings for 'mining train'.

Three S Scale Mining Related Business Kits New in Box NIB Sn3 Kit
Three S Scale Mining Related Business Kits New in Box NIB Sn3 Kit
$126.50 (6 Bids)
Time Remaining: 3d 4h 54m
The No Frills Prototype Picture Guide to Modeling Ore Mines  Mills 5 Disc Set
The No Frills Prototype Picture Guide to Modeling Ore Mines Mills 5 Disc Set
$29.99
Time Remaining: 3d 12h 41m
Buy It Now for only: $29.99
Five 5 Mining Related Building Kits by Lehigh ValleyNIB S Scale Sn3 Kit
Five 5 Mining Related Building Kits by Lehigh ValleyNIB S Scale Sn3 Kit
$46.00 (3 Bids)
Time Remaining: 4d 5h 32m
O SCALE On3 On30 WISEMAN MODEL SERVICES LOGGING OR MINING CAMP 4 CABIN SET KIT
O SCALE On3 On30 WISEMAN MODEL SERVICES LOGGING OR MINING CAMP 4 CABIN SET KIT
$89.95
Time Remaining: 6d 2h 2m
Buy It Now for only: $89.95
On30HO Side Dump Wagons Mining car Ore Erz Car x 3pcs 3 Stck set per box
On30HO Side Dump Wagons Mining car Ore Erz Car x 3pcs 3 Stck set per box
$69.00
Time Remaining: 7d 11h 8m
Buy It Now for only: $69.00
HO HON3 CUSTOM BUILT FROM SCRATCH DOLLY VARDON MINE FINISHED MODEL
HO HON3 CUSTOM BUILT FROM SCRATCH DOLLY VARDON MINE FINISHED MODEL
$275.00
Time Remaining: 21d 2h 58m
Buy It Now for only: $275.00
On30 Bachmann Logging  Mining Car Wood Sided Dmp Car 3 pcs
On30 Bachmann Logging Mining Car Wood Sided Dmp Car 3 pcs
$74.99
Time Remaining: 28d 10m
Buy It Now for only: $74.99

Other On30 Scale train items recently purchased through this site:

Five 5 Mining Related Building Kits by Lehigh ValleyNIB S Scale Sn3 Kit
HO HON3 CUSTOM BUILT FROM SCRATCH DOLLY VARDON MINE FINISHED MODEL
Three S Scale Mining Related Business Kits New in Box NIB Sn3 Kit
On30 Bachmann Logging Mining Car Wood Sided Dmp Car 3 pcs
O SCALE On3 On30 WISEMAN MODEL SERVICES LOGGING OR MINING CAMP 4 CABIN SET KIT
The No Frills Prototype Picture Guide to Modeling Ore Mines Mills 5 Disc Set
On30HO Side Dump Wagons Mining car Ore Erz Car x 3pcs 3 Stck set per box