For more information on the USGS-the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment, visit http://www.usgs.gov or call 1-888-ASK-USGS For an overview of USGS information products, including maps, imagery, and publications, visit http://www.usgs.gov/pubprodTo order this and other USGS information products, visit http://store.usgs.gov Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report. AbstractThis report, prepared in cooperation with the Pennsylvania Department of Environmental Protection (PaDEP), the Eastern Pennsylvania Coalition for Abandoned Mine Reclamation, and the Dauphin County Conservation District, provides estimates of water budgets and groundwater volumes stored in abandoned underground mines in the Western Middle Anthracite Coalfield, which encompasses an area of 120 square miles in eastern Pennsylvania. The estimates are based on preliminary simulations using a groundwater-flow model and an associated geographic information system that integrates data on the mining features, hydrogeology, and streamflow in the study area. The Mahanoy and Shamokin Creek Basins were the focus of the study because these basins exhibit extensive hydrologic effects and water-quality degradation from the abandoned mines in their headwaters in the Western Middle Anthracite Coalfield. Proposed groundwater withdrawals from the flooded parts of the mines and stream-channel modifications in selected areas have the potential for altering the distribution of groundwater and the interaction between the groundwater and streams in the area.Preliminary three-dimensional, steady-state simulations of groundwater flow by the use of MODFLOW are presented to summarize information on the exchange of groundwater among adjacent mines and to help guide the management of ongoing data collection, reclamation activities, and water-use planning. The conceptual model includes high-permeability mine voids that are connected vertically and horizontally 1 USGS Pennsylvania Water Science Center.2 Independent consultant (deceased). within multicolliery units (MCUs). MCUs were identified on the basis of mine maps, locations of mine discharges, and groundwater levels in the mines measured by PaDEP. The locations and integrity of mine barriers were determined from mine maps and groundwater levels. The permeability of intact barriers is low, reflecting the hydraulic characteristics of unmined host rock and coal.A steady-state model was calibrated to measured groundwater levels and stream base flow, the latter at many locations composed primarily of discharge from mines. Automatic parameter estimation used MODFLOW-2000 with manual adjustments to constrain parameter values to realistic ranges. The calibrated model supports the conceptua...
The second year of method development work was conducted on the ADTI-WP1 (Humidity Cell) and the ADTI-WP2 (Leaching Column) standard test methods. The performance of the leaching column method was superior to the humidity cell method. In making improvements to the leaching column method, variations in column diameter and water-handling/gas-handling procedures were evaluated. Two commercial laboratories and a university research lab participated in the study. Relative percent differences between duplicate samples and relative standard deviations between laboratories were evaluated. Surface area measurements, using BET methods, were conducted on each of 8 particle size classes, before and after weathering tests on 4 different lithologic samples. Observed alkalinity concentrations were consistent with the elevated PCO 2 and approached saturation with respect to calcite for calcareous rocks. The maximum concentrations of acidity (33,700 mg/L), sulfates (37,404 mg/L) and iron (9,120 mg/L) for the high-sulfur coal refuse sample were consistent with the maximum concentrations observed in the field. The measured surface areas of the shale samples were significantly higher than the sandstone, limestone and coalrefuse samples. However, the surface area measurements post-weathering were not significantly different from the pre-weathering measurements for most rock samples and most particle size classes.
Most previous coal mine drainage leaching studies have not investigated the effect of surface area, effects of elevated Pco 2 , which are typical of mine spoil, and solubility constraints on water chemistry. The leaching column and humidity cell tests were designed to evaluate the importance of these parameters. Surface area was examined on three rock types before and after leaching: the Brush Creek shale; a well-indurated calcareous sandstone; and a coal refuse. The surface area, as measured by BET, for the shale was an order of magnitude greater than the other rock types. Surface area after leaching decreased slightly for the shale, and by half for the refuse. The sandstone area remained the same. Plots of sulfate concentration through time closely resemble those expected for diffusioncontrolled kinetics. Plots of alkalinity through time are characteristic of a material that dissolves quickly at first and then approaches or reaches saturation. Saturation with respect to calcite was confirmed by equilibrium calculations. The water in the leaching columns was undersaturated with respect to gypsum, indicating that sulfate was a conservative parameter and could be used to measure pyrite oxidation rates. The target 10% CO 2 was achieved in the column tests, but not achieved in the humidity cell tests. At the end of 12 to 14 weeks, between 1.5 and 2% of the calcite and between 4 and 6% of the sulfur in the rock had been removed by weathering. Predictions, based on power function equations, indicate that the Brush Creek shale sample would remain alkaline even if weathered for years. Comparisons between leaching chemistry and field data for the Brush Creek shale and the coal refuse sample showed similar water chemistry.
Abstract. Simulated weathering tests are used to estimate leachate quality from rocks containing varying concentrations of pyrite and carbonates at mines. Five rock samples of coal overburden materials were subjected to a standardized column leaching test at eight commercial, university and government laboratories. Splits from sized, homogenized bulk samples were loaded in duplicate columns, incubated under humid air containing 10% CO 2 , and leached every 7 days for a 14 week period. Leachates were analyzed for mine drainage parameters including acidity, alkalinity, metals, sulfate and selected trace elements.Relative percent difference (RPD) and relative standard deviation (RSD) statistics show the variation within individual labs and among the group of labs. Fe, Al, Se, Zn and Acidity exhibited the greatest variability in results across all rock samples and labs. RPD's usually exceeded 30% for these parameters. The variation in Fe and Acidity increased with weathering duration. Ca, Mg, Na, SO 4, and specific conductance were the most consistent parameters. Mass weighting the chemical concentrations to account for differences in sample mass and leachate volumes did not noticeably improve the RPD and RSD statistics. Cumulative quantities leached were, however, consistent among labs for most parameters.About 2 to 6 % of the total sulfur present in the rocks was leached during the test. One rock sample was near saturation for gypsum, and some sulfate may have been retained in the column. Acid neutralizing capacity was depleted at a faster rate than acid producing potential. Carbonate dissolution varied, with 3 of 5 rocks producing solutions that were saturated for calcite, while two rocks produced under-saturated solutions. Four of five rocks had less than 5 % of total Ca and Mg leached, with similar or smaller leaching fractions for other elements. More than 90% of the iron mobilized by pyrite weathering was retained in the column for all samples. One acid forming sample leached elements more aggressively than the rocks producing neutral leachates.The inter-lab results show that the standard column test can yield consistent estimates of mine water composition, and differentiate the behavior of various rock and mineral assemblages. __________________
In 1995, the U.S. Office of Surface Mining (OSM) and the National Mine Land Reclamation Center (NMLRC) joined with the Interstate Mining Compact Commission, the National Mining Association, academia, and other Federal agencies to form the Acid Drainage Technology Initiative (ADTI). The ADTI partnership seeks to identify, evaluate and develop "best science" based practices to prevent new acid mine drainage sources and eliminate existing sources. The ADTI partnership developed a management structure to oversee the program and developed action plans to address key technical areas. The ADTI organization consists of a coal mining sector, a metal mining sector and a secretariat, overseen by an Operations Committee. The coal mining sector of ADTI is divided into a prediction working group and an avoidance and remediation working group to implement and coordinate the research strategy. This paper summarizes the results of the coal mining sector efforts since the completion of the avoidance and remediation, and prediction handbooks in 1998 and 2000, respectively, and the status of current activities. The activities have included field verification of acid drainage predictions using acid-base accounting, monitoring and follow up evaluation of acid mine drainage passive and in-situ treatment systems, developing standardized kinetic testing protocols, flooded underground mine pools, and issues related to elevated selenium in streams associated with surface mines.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.