| Popis: |
The approximately 120 ha backfilled Fire Road coal mine cut, located near Fredericton New Brunswick, has been a source of acid rock drainage since the mid 1980’s. Lime neutralization treatment of drainage has been continuously ongoing. The cut, with depths to approximately 20 m, is located in sandstones containing iron sulphides, principally pyrite, in the range of 1 to 2 wt%. Site water chemistry has been intensively monitored over the years using a series of groundwater wells within and bordering the disturbed areas. This has provided a considerable inventory of water chemistry data which has enabled interpretation of the characteristics of acid generation at the site; the effectiveness of “in situ” neutralization in reducing the ultimate acidity of the drainage, and trends in acidity over the years. During the past number of years a definite trend of decreasing acidity has been observed leading to the conclusion that the site should exhibit “zero lime demand” within the next 10 years. At present, plans are being developed for final closure of the site. |
