Publications— Scientific Investigations Report

Effects of Historical Coal Mining and Drainage from Abandoned Mines on Streamflow and Water Quality in Newport and Nanticoke Creeks, Luzerne County, Pennsylvania, 1999--2000

U.S. Geological Survey Scientific Investigations Report 2007-5061

By Jeffrey J. Chaplin, Charles A. Cravotta III, Jeffrey B. Weitzel, and Kenneth M. Klemow

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Abstract

This report characterizes the effects of historical mining and abandoned mine drainage (AMD) on streamflow and water quality and evaluates potential strategies for AMD abatement in the 14-square-mile Newport Creek Basin and 7.6-square-mile Nanticoke Creek Basin. Both basins are mostly within the Northern Anthracite Coal Field and drain to the Susquehanna River in central Luzerne County, Pa. The U.S. Geological Survey (USGS), in cooperation with the Earth Conservancy, conducted an assessment from April 1999 to September 2000 that included (1) continuous stage measurement at 7 sites; (2) synoptic water-quality and flow sampling at 21 sites on June 2-4, 1999, and at 24 sites on October 7-8, 1999; and (3) periodic measurement of flow and water quality at 26 additional sites not included in the synoptic sampling effort.

Stream water and surface runoff from the unmined uplands drain northward to the valley, where most of the water is intercepted and diverted into abandoned underground mines. Water that infiltrates into the mine workings becomes loaded with acidity, metals, and sulfate and later discharges as AMD at topographically low points along lower reaches of Newport Creek, Nanticoke Creek, and their tributaries. Differences among streamflows in unmined and mined areas of the watersheds indicated that (1) intermediate stream reaches within the mined area but upgradient of AMD sites generally were either dry or losing reaches, (2) ground water flowing to AMD sites could cross beneath surface-drainage divides, and (3) AMD discharging to the lower stream reaches restored volumes lost in the upstream reaches.

The synoptic data for June and October 1999, along with continuous stage data during the study period, indicated flows during synoptic surveys were comparable to average values. The headwaters upstream of the mined area generally were oxygenated (dissolved oxygen range was 4.7 to 11.0 mg/L [milligrams per liter]), near-neutral (pH range was 5.8 to 7.6), and net alkaline (net alkalinity range was 2.0 to 25.0 mg/L CaCO₃), with relatively low concentrations of sulfate (6.40 to 24.0 mg/L) and dissolved metals (less than 500 μg/L [micrograms per liter] of iron, manganese, and aluminum). In contrast, the AMD discharges and downstream waters were characterized by elevated concentrations of sulfate and dissolved metals that exceeded Federal and State regulatory limits.

The largest AMD sources were the Susquehanna Number 7 Mine discharge entering Newport Creek near its mouth (flow range was 4.7 to 19 ft³/s [cubic feet per second]), the Truesdale Mine Discharge (Dundee Outfall) entering Nanticoke Creek about 0.5 mile upstream of Loomis Park (flow range was 0.00 to 38 ft³/s), and a mine-pit overflow entering near the midpoint of Newport Creek (flow range was 4.0 to 6.9 ft³/s). The three large discharges were poorly oxygenated (dissolved oxygen concentration range was <0.05 to 6.4 mg/L) and had elevated concentrations of sulfate (range was 710 to 890 mg/L) and low concentrations of dissolved aluminum (less than 25 μg/L), but they had distinctive concentrations of net alkalinity and dissolved iron and manganese. Effluent from the Susquehanna Number 7 Mine was near-neutral (pH range was 5.9 to 6.6) and net alkaline (net alkalinity range was 12.0 to 42.0 mg/L CaCO₃) with elevated concentrations of sulfate (718 to 1,170 mg/L), dissolved iron (52,500 to 77,400 μg/L), and manganese (5,200 to 5,300 μg/L). Effluent from the Truesdale Mine also was near-neutral (pH range was 5.9 to 6.3) but had variable net alkalinity (-19.0 to 57.0 mg/L CaCO₃) with elevated concentrations of sulfate (571 to 740 mg/L), dissolved iron (30,500 to 43,000 μg/L), and manganese (3,600 to 5,200 μg/L). Effluent from the mine-pit overflow in Newport Creek Basin was acidic (pH range was 4.3 to 5.0; net alkalinity range was -42 to -38 mg/L CaCO₃) with elevated concentrations of sulfate (800 to 840 mg/L), iron (13,000 to 16,000 μg/L), and manganese (6,800 to 7,000 μg/L). Although the three large AMD sources did not contain detectable concentrations of dissolved aluminum, a small AMD source in the Nanticoke Creek Basin (flow less than 0.01 ft³/s to 0.06 ft³/s), along with other small AMD sources entering the South Branch of Newport Creek between Wanamie and Sheatown (flows less than 0.89 ft³/s), had elevated concentrations of dissolved aluminum (3,100 to 38,600 μg/L) that exceeded criteria for protection of aquatic organisms.

The chemistry of stream water after mixing with AMD inputs was variable, depending on the relative quantities of AMD and other water sources. For example, decreased flow rates and net alkalinities of AMD from the Truesdale Mine coupled with increased acid production from more extensive iron hydrolysis within Nanticoke Creek could explain the acidic quality about 0.5 mile downstream of the mine during drought (minimum pH was 3.2) compared to the near-neutral quality during normal flows (median pH was 6.8). Other co-occurring influences such as alkalinity from intermittent sewage inflows could explain the bimodal pH distribution near the mouth of South Branch; water had near-neutral pH (pH greater than 6.0) when sewage was abundant but acidic pH (less than 4.5) when it was not.

AMD in other mined areas with chemistry and flow similar to the discharges sampled for this study, has been treated with passive strategies that may include amendment of influent chemistry and almost always include retention in aerobic wetlands. For water similar in quality and quantity to the Truesdale Mine Discharge, with iron loading rates approaching 326 kilograms per day, aerobic wetlands of 4 to 16 acres combined with an alkalinity source have been used for passive treatment. For large, consistently net alkaline flows, such as the AMD discharge from the Susquehanna Number 7 Mine, wetlands of 12 to 49 acres have been used to remove dissolved iron, without supplemental alkalinity, provided that pH is maintained near neutrality. AMD sources with large flow rates, low pH, and elevated concentrations of dissolved metals, such as the mine-pit overflow, commonly warrant active treatment. For example, efficient alkalinity-producing systems, such as lime dosing, followed by ponds or wetlands of approximately 3 to 13 acres have been used to neutralize AMD and remove dissolved iron for similar situations.

Abstract
Introduction
     Purpose and Scope
     Description of the Study Area
          Geology and Mining History
          Hydrologic Setting
     Water-Quality Degradation, Protection Standards, and Remediation Practices
Study Design and Methods
     Computation of Continuous Flow Record
     Methods of Water-Quality Sampling and Analysis
Effects of Historical Coal Mining and Drainage from Abandoned Mines
     Hydrology
     Stream-Water and Mine-Discharge Quality
          Water-Quality Variations
          Effects of Iron Oxidation and Hydrolysis on Water Quality
          Concentrations of Metals
Potential Passive-Treatment Strategies for Newport and Nanticoke Creeks
Summary
Acknowledgments
References Cited
Appendix 1--Digital reproductions of out of print reports
Appendix 2--Data used for figures, tables, and statistics