Abandoned Mine Drainage (AMD)

Abandoned Mine Drainage (AMD) is drainage flowing from, or caused by, deep mining, surface mining, or coal refuse piles. These sites were generally abandoned prior to present-day mining regulations with no responsible party. Drainage may be acidic or alkaline, with elevated levels of dissolved metals.

Where Does AMD Originate?
Surface Mining: past unregulated strip mining
Deep Mining: underground tunnels
Bore Holes: holes drilled to relieve pressure in deep mines
Refuse Piles: waste coal otherwise known as bony piles

What Are the Indicators of AMD?
1. Little or no evidence of aquatic life
2. Low pH or high metals concentrations in the stream
3. Stream bottom coating and/or
4. Stream discoloration
5. Colors that indicate metals are present:
Orange: evidence of iron, Grayish-white: evidence of aluminum, Black: evidence of manganese

How is AMD Treated?
1. Active Treatment: acidic discharges are neutralized by the addition of strong alkaline chemicals such as lime or ammonia.

2. Passive Treatment: naturally occurring chemical and biological reactions are established in a controlled environment.

AMD passes through one or several of these systems:

• Wetlands: including marshes, swamps, or bogs
• Open limestone channels: ditches lined with limestone sand
• Diversion wells: a holding tank filled with crushed lime
• Anoxic limestone drains: beds of buried limestone

The Goal of AMD Treatment
is to restore an aquatic system to its natural state. Monitoring the chemistry, aquatic life, and stream flow rates before and after restoration offers many opportunities for volunteers and environmental education programs. Stream monitoring establishes the necessary data to prioritize sites for clean-up.