Minesoil Properties of 15 Abandoned Mine Land Sites in West Virginia

The characteristics of minesoils on abandoned mine land (AML) often dictate which plant species will invade and establish from nearby undisturbed areas. This study measured physical and chemical minesoil properties on 15 AML sites in northern West Virginia and matched these properties to vegetation cover. Fifteen sites ranging in age from 13 to 35 yr old were selected from three surface-mined coal beds (Pittsburgh, Freeport, and Kittanning). On each site, three 1 m-deep pits were dug and minesoil samples were extracted from two horizons, and vegetation was sampled in three 100-m2 plots near the pits. Minesoils on Freeport sites had more rock fragments and sand than either Pittsburgh or Kittanning sites. No particle-size changes with depth or age were evident between horizons in any minesoil. Acidity increased and pH decreased with minesoil age on Pittsburgh and Kittanning minesoils due to the oxidation of pyritic materials near the soil surface. A cluster analysis distinguished three minesoil types on these sites. Minesoil type A had low acidity and high CEC. Minesoil type B had high acidity and moderate CEC. Minesoil type C had high rock fragment content, low to moderate acidity, and low CEC. Minesoii type A was completely covered by herbaceous plants and trees, while minesoil types B and C were generally covered by trees. Based on our minesoil analyses and other studies, barren AML sites may not require complete redisturbance for revegetation but may be revegetated by adjacent plant species if surface amendments are applied. a~PROXIMATELY 34000 ha of mined land in West Virginia were designated as abandoned mine land (AML) in 1977 (USDA-SCS, 1979). Abandoned land sites are mining disturbances that were inadequately reclaimed before the passage of the Surface Mining Control and Reclamation Act (SMCRA) on 3 Aug. 1977, and where no company or individual has any reclamation responsibility under state or federal laws. Title IV in SMCRA created a fund to reclaim AML sites by taxing each ton of mined coal. Approximately $3.5 billion were collected from 1977 to 1994. Up to 50% of the tax money from each state can be returned to the state for AML reclamation based on an AML inventory and site eligibility. In spite of the large amount of money generated, Congress realized that the fund would be inadequate to reclaim all AML sites and established a priority system for ranking AML sites for reclamation. In West Virginia alone, $2.5 billion is estimated to reclaim just the Priority 1 and 2 sites, which are sites that pose public health and property hazards. From 1977 to 1992, the West Virginia State AML Program reclaimed about 2200 ha and eliminated 310 of the most dangerous and degraded AML sites. The Office of Surface Mining estimates that only about 6% of West Virginia’s AML problems were corC.D. Johnson, Florida Inst. of Phosphate Res., Barrow, FL 33830; and J.G. Skousen, Division of Plant and Soil Sciences, West Virginia Univ., Morgantown, WV 26506-6108. Scientific contribution no. 2452 from the West Virginia Agric. Exp. Stn., Morgantown. This research was funded by the U.S. Bureau of Mines, National Mine Land Reclamation Center under contract no. CO388026 and by funds appropriated under the Hatch Act. Received 1 Sept. 1994. *Corresponding author. Published in J. Environ. Qual. 24:635-643 0995). rected from 1977 to 1992 (USDI-OSM, 1992). Other Appalachian states are similar in AML problems and disturbed areas reclaimed. Some AML sites will gradually revegetate in a relatively short time (i.e., 10-20 yr), causing decreased erosion and increased soil development, and may not require AML funding for reclamation. Such sites have fertile minesoils with few physical and chemical properties that limit plant recruitment and growth. Other AML sites with edaphic problems that restrict plant establishment may take much longer (decades to centuries) for natural processes to enable revegetation and stabilization. Abandoned mine land reclamation usually requires burying acid-producing materials with borrowed topsoil for plant establishment and eliminating dangerous conditions and structures on the site. Minesoils undergo rapid changes in chemical and physical properties as a result of accelerated pedogenic weathering processes (Drury and Nisbet, 1973). These weathering processes act on fresh geologic materials that are not in equilibrium with the surface soil environment (Roberts et al., 1988). The degree to which sites become vegetated naturally may be related to surrounding vegetation (Bramble and Ashley, 1955; Gibson et al., 1985; Skousen et al., 1994), and the quality of the minesoil such as rock fragment content, horizon development, and pH and acidity (Bell and Ungar, 1981; Daniels and Amos, 1981; Schramm, 1966; Smith et al., 1971). Minesoils in the Eastern Coal Region of the USA generally have high rock fragment content when compared with surrounding native soils (Pedersen et al., 1978; Thurman and Sencindiver, 1986). For example, Pennsylvania minesoils had a rock fragment content of >70% in subsoils and 50% in surface horizons (Ciolkosz et al., 1985). Small rock fragments between 2 and 5 cm were more prevalent in surface horizons than subsurface horizons due to weathering of larger fragments to smaller fragments. Once rock fragments were sieved out, textures of minesoils from 25 to 100 yr old were similar to surrounding native soils (Smith et al., 1971; Thurman and Sencindiver, 1986). Minesoils have at least two horizons: a distinguishable surface horizon, and a lower horizon having poor structure, no roots, and various sizes of rock fragments. Surface horizons are formed by chemical and physical weathering due to plant roots and sunlight/precipitation, and often contain some organic matter and a high percentage of fine earth material (Sencindiver, 1977). Two minesoils in West Virginia had higher bulk densities and lower porosities than surrounding native soils (Thurman and Sencindiver, 1986), and shallow compacted layers that restricted water, air, and root penetration were found in Virginia minesoils (Daniels and Amos, 1981). Abbreviations: AML, abandoned mine land; SMCRA, Surface Mining Control and Reclamation Act; WRD, water retention difference; POR, total porosity; CEC, cation exchange capacity; BS, base saturation; NP, neutralization potential; EC, electrical conductivity.