The duration of acid mine drainage flowing out of underground mines is important in the design of watershed restoration and abandoned mine land reclamation projects. Past studies have reported that acid water flows from underground mines for hundreds of years with little change, while others state that poor drainage quality may last only 20 to 40 years. More than 150 above-drainage (those not flooded after abandonment) underground mine discharges from Pittsburgh and Upper Freeport coal seams were located and sampled during 1968 in northern West Virginia, and we revisited 44 of those sites in 1999-2000 and measured water flow, pH, acidity, Fe, sulfate, and conductivity. We found no significant difference in flows between 1968 and 1999-2000. Therefore, we felt the water quality data could be compared and the data represented real changes in pollutant concentrations. There were significant water quality differences between year and coal seam, but no effect of disturbance. While pH was not significantly improved, average total acidity declined 79% between 1968 and 1999-2000 in Pittsburgh mines (from 66.8 to 14 mmol H+ L(-1)) and 56% in Upper Freeport mines (from 23.8 to 10.4 mmol H+ L(-1)). Iron decreased an average of about 80% across all sites (from an average of 400 to 72 mg L(-1)), while sulfate decreased between 50 and 75%. Pittsburgh seam discharge water was much worse in 1968 than Upper Freeport seam water. Twenty of our 44 sites had water quality information in 1980, which served as a midpoint to assess the slope of the decline in acidity and metal concentrations. Five of 20 sites (25%) showed an apparent exponential rate of decline in acidity and iron, while 10 of 20 sites (50%) showed a more linear decline. Drainage from five Upper Freeport sites increased in acidity and iron. While it is clear that surface mines and below-drainage underground mines improve in discharge quality relatively rapidly (20-40 years), above-drainage underground mines are not as easily predicted. In total, the drainage from 34 out of 44 (77%) above-drainage underground mines showed significant improvement in acidity over time, some exponentially and some linearly. Ten discharges showed no improvement and three of these got much worse.

Acid mine drainage (AMD) is a serious problem in many watersheds where coal is mined. Passive treatments, such as wetlands and anoxic limestone drains (ALDs), have been developed, but these technologies show varying treatment efficiencies. A new passive treatment technique is a vertical flow wetland or successive alkalinity producing system (SAPS). Four SAPS in Pennsylvania were studied to determine changes in water chemistry from inflow to outflow. The Howe Bridge SAPS removed about 130 mg l 1 (40%) of the inflow acidity concentration and about 100 mg l 1 (60%) iron (Fe). The Filson 1 SAPS removed 68 mg l 1 (26%) acidity, 20 mg l 1 (83%) Fe and 6 mg l 1 (35%) aluminium (Al). The Sommerville SAPS removed 112 mg l 1 (31%) acidity, exported Fe, and removed 13 mg l 1 (30%) Al. The McKinley SAPS removed 54 mg l 1 (91%) acidity and 5 mg l 1 (90%) Fe. Acid removal rates at our four sites were 17 (HB), 52 (Filson1), 18 (Sommerville) and 11 (McKinley) g of acid per m 2 of surface wetland area per day (g/m 2 d 1 ). Calcium (Ca) concentrations in the SAPS effluents were increased between 8 and 57 mg l 1 at these sites. Equilibrators, which were inserted into compost layers to evaluate redox conditions at our sites, showed that reducing conditions were generally found at 60 cm compost depths and oxidized conditions were found at 30 cm compost depths. Deeply oxidized zones substantiated observations that channel flow was occurring through some parts of the compost. The Howe Bridge site has not declined in treatment efficiency over a six year treatment life. The SAPS construction costs were equal to about seven years of NaOH chemical treatment costs and 30 years of lime treatment costs. So, if the SAPS treatment longevity is seven years or greater and comparable effluent water quality was achieved, the SAPS construction was cost effective compared to NaOH chemical treatment. Construction recommendations for SAPS include a minimum of 50 cm of compost thickness, periodic replacement or addition of fresh compost material, and increasing the number of drainage pipes underlying the limestone.

About 90 percent of the untreated acid mine drainage in the northern Appalachian coal originates in underground mines. These mines were developed and abandoned before laws were enacted that require reclamation, sealing and closure, and water treatment. Since no one is legally responsible for treating this water, treatment may never occur and pollution from these sites will impact streams for decades. Changes in water quality from underground mine discharges over several decades was investigated, and the decay rate of sulfate discharge from these sites was evaluated. Water quality data was collected from underground mines that were sampled in 1999, and correlated to data collected during a 1968 study. The mines discharging acidity were characterized as to geology and coal seam, size of the mine, volume of coal removed during operation, age, and other factors. All eleven mine discharges improved in acidity and sulfate concentrations between the 1968 and 1999 samplings. A 2 percent decay rate was determined by I) calculating the decline of sulfate concentration between these two dates, 2) calculating sulfate declines from data of two other sources, and 3) back-calculating to the. original amount of coal remaining in the mine. This number is important because it allows for the calculation oflong-term trends of water discharging from underground mines and will help in remediation schemes.

Water quality changes of underground mines in Northern West Virginia Jennifer Demchak Acid mine drainage (AMD) is a serious problem from both abandoned surface and underground mines, and about 10,000 km of streams have been impacted by AMD in the northeastern U.S. (Pennsylvania, Maryland, Ohio, and West Virginia). Streams in the region have shown improvement over time and this improvement has been partly attributed to reclamation of mined sites and natural attenuation of AMD impacts. This study was initiated to determine the water quality changes from underground mines over time in northern West Virginia. In order to compare chemistry data across years and seasons with varying flow, relationships between discharge rates and acidity values were assessed. Results indicate that water quality from the majority of abandoned, above drainage underground mines did significantly improve over time, some exponentially and some linearly. The amount of improvement varied with coal seams. Graphs plotting flow and precipitation showed the highest flows generally in the spring and low flows in the fall. Acidity concentrations from two underground mines did not change significantly with varying discharge rates, which neither supports previous ideas of a flushing or dilution of acid salts from the mine. One mine, T&T, showed a slight trend of highest acidity values at high flows, while Omega showed highest acidity at low flows. Additional long term data sets with frequent flow and acidity data will be necessary to confirm these results.