| Mine Name and YSU Mine Number | THORNHILL | MAHO000077 |
| Townships | Youngstown | ... | ... | Quadrangle 001 | Youngstown Quad |
| Lots | Quadrangle 002 | ... |
| County, State | Mahoning | OH | UTM |
| DOM Map Number | MG-73 | Seam Elevation | 900.5-905.0' |
| OGS Mine Number | Seam Thickness |
| USBM Document Number | 321605 | Cover Thickness | 61.5'ASO |
| Mine Type and Commodity Mined | SHAFT & SLOPE | COAL | Drain Level |
| Seam Code 001 | JACKSON NO.1, MASSILLON, NO.1, SHARON | Hazard Potential | HIGH & MOD |
| Seam Code 002 | Seam Information Unavailable | Mapped | Yes |
| Date Opened | Date Closed | Located | Yes |
| Operator 001 | WALSH COAL CO. | Operator 001 Date Opened |
| Operator 001 Date Closed |
| Operator 002 | THORNHILL COAL CO. | Operator 002 Date Opened |
| Operator 002 Date Closed |
| Operator 003 | ... | Operator 003 Date Opened |
| Operator 003 Date Closed |
| Operator 004 | ... | Operator 004 Date Opened |
| Operator 004 Date Closed |
| Operator 005 | ... | Operator 005 Date Opened |
| Operator 005 Date Closed |
| Operator 006 | ... | Operator 006 Date Opened |
| Operator 006 Date Closed |
| Operator 007 | ... | Operator 007 Date Opened |
| Operator 007 Date Closed |
| Operator 008 | ... | Operator 008 Date Opened |
| Operator 008 Date Closed |
| Remarks | Mine map [1] shows: old slope; approximate area of old workings; 61.5' shaft, top elev. 962.0', |
| bottom elev. 900.5'. Coal identified by elevation. Not located. |
| Last Update: | Wednesday, February 17, 1999 |