Acid mine drainage
A003 JANUARY 2020
Acid mine drainage (AMD) refers to the outflow of acidic water from a mining site. In most cases, this acid comes primarily from oxidation of iron sulfide (FeS2, also known as pyrite or “fool’s gold”), which is often found in conjunction with valuable metals. Acid mine drainage is a major problem with many hardrock mines, including almost all mines where the metal ore is bound up with sulfur (metal sulfide mines). A significant number of coal mines also suffer from acid mine drainage.
The metals dissolved by the acid drainage poison downstream waters, in many cases to the point where nothing other than microbes can survive.
Acid mine drainage is a worldwide problem, leading to ecological destruction in watersheds and the contamination of human water sources by sulfuric acid and heavy metals, including arsenic, copper, and lead. Once acid-generating rock is crushed and exposed to oxygen and the surface environment, acid generation is very difficult to contain or stop, and can continue for tens or thousands of years until the available sulfide minerals are exhausted. Roman-era mines have been identified which are still producing acid mine drainage. It is the irreversibility of the process of turning relatively inert ore into tremendous volumes of hazardous waste, the very long hazard-life of the material, and the extreme difficulty of containment which make acid mine drainage such a serious and persistent issue.
- Acid mine drainage is prevalent in areas where gold and coal mining occurs
- It is caused by the oxidation of pyrite – this produces sulphuric acid
- The resultant pH can be as low as 2.0
- Acid drainage is harmful to the environment
- Acid mine drainage is a causer of ground water contamination
- It is almost impossible to ‘cure’, but easily preventable- ie no mining in such areas
- Local rock in the Sperrins is prevalent in pyrite and naturally occuring heavy metals- and also has above average rainfall- perfect conditions for acid mine drainage.
Berkley pit Montana-
Berkley pit Montana- 35000 tourists visit this ‘disaster scene’ every year to witness the environmental catastophie that unveilled when the mine stopped working, flooded and became contaminated with very acidic water.
This was the scene where almost 3000 geese died in a single night after they seeked refuge for the evening when avoiding a snow storm on their migratory route. As you will see there is a lot of money and effort in trying to manage this risk today, but you have got to agree that it would have been best not to happen in the first place.
Like the Berkely pit, the native country rock around Tyrone, especially in the Curraghinalt and Cavanacaw areas are prolific in natural pyrite- which is one of the main ingredients/causes for this phenomeonon. The pyrite oxidises in the presence of water and air, and forms Sulpuric acid, which in turn dissolves other metal minerals present in the rock to form a lethal toxic cocktail.
Do you think our local friendly mining companies have budgeted to cover the costs of this clean up? Considering Galantas are loosing money ‘hand over fist’, and regulary need additional private placements to survive- I wonder if the ‘who cleans this up when you fail’ question has been asked?
Perhaps it’s Dalradian and Galantas intentions to operate ‘Devastiation tours’ to paying tourists in the future- “Remember when this was a green, beautiful landscape, abundant diverse wildlife- hey look at it now. That will be $3 Mam”