Abandoned mine lands (AML) are lands and waters adversely impacted by inadequately reclaimed pre-1977 coal mining operations. Environmental restoration activities performed in accordance with the Surface Mining Control and Reclamation Act of 1977 (SMCRA) correct or mitigate these problems. An inventory of land and water impacted by past coal mining is maintained containing information on the location, type and extent of AML impacts. Based on field surveys, the inventory is updated and maintained as new problems are identified and existing problems are reclaimed. AML problems are classified by type and priority.
The most serious AML problems are those posing a threat to health and safety of people (Priority 1 and Priority 2, or "high priority"). There are 17 Priority 1 and 2 problem types. These problem types are those being addressed by the Bureau of Abandoned Mine Reclamation using funds from SMCRA and are described below.
Priority 1 and 2 Problem Types
| Problem Type | Symbol | |
| Clogged Stream (PDF) | CS | |
| Clogged Stream Lands (PDF) | CSL | |
| Dangerous Highwall (PDF) | DH | |
| Dangerous Impoundments (PDF) | DI | |
| Dangerous Pile and Embankment (PDF) | DPE | |
| Dangerous Slides (PDF) | DS | |
| Gases: Hazardous or Explosive (PDF) | GHE | |
| Hazardous Equipment & Facilities (PDF) | HEF | |
| Hazardous Water Body (PDF) | HWB | |
| Industrial or Residential Waste (PDF) | IRW | |
| Polluted Water: Agricultural & Industrial (PDF) | PWAI | |
| Polluted Water: Human Consumption (PDF) | PWHC | |
| Portals (PDF) | P | |
| Subsidence (PDF) | S | |
| Surface Burning (PDF) | SB | |
| Underground Mine Fire (PDF) | UMF | |
| Vertical Opening (PDF) | VO |
AML problems impacting the environment that do not meet the high priority criteria are classified as Priority 3 problems. Under limited circumstances, these problems can be addressed using funds from SMCRA, most commonly when they are reclaimed in conjunction with high priority problems. Additional information on Priority 1, Priority 2, and Priority 3 problems is available on OSM's website.
The environmental impacts of abandoned mine drainage may be addressed using "AMD Set-Aside" funding. This funding can be used where mine drainage discharges adversely impact biological resources, and the impacted watershed meets the criteria of a "Qualified Hydrological Unit" as defined in SMCRA.