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SENCINDIVER & AMMONS
<br />o moderately acid spoil derived
<br />shale and limestone strata with
<br />hales— Pittsburgh and Redstone
<br />I spoil derived from geologic sec -
<br />>nes— Bakerstown and Freeport
<br />)erties, proved to be useful and it
<br />ner, Smith, and Galpin (1948) in
<br />d lands on maps and referred to
<br />trip mines (Losche & Beverage,
<br />given. In some areas, mine -land
<br />fined lands into various categories
<br />n et al., 1959; Davis, 1965; Soil
<br />were based on pH, texture or par -
<br />the 1970s, increased interest in
<br />T a new suborder (Sencindiver,
<br />y: A Basic System of Soil Classi-
<br />eys (Soil Surv. Staff, 1975), and
<br />rimarily at the great group level
<br />80s, minesoil series were estab-
<br />ve been established, pedologists
<br />these soils, and renewed interest
<br />ternational levels. Therefore, the
<br />f the published information rela-
<br />s.
<br />IOLOGY
<br />distinctly different morpholog-
<br />are developing from mixtures of
<br />perties are often determined by
<br />,tural processes. Some of these
<br />and overburden characterization
<br />n methods are known (Indorante
<br />c, 1978). Most native soils con -
<br />ises acting through thousands of
<br />equilibrium with their soil form -
<br />may continue to approach and
<br />Is, some properties may remain
<br />may accelerate the soil- forming
<br />;o that air, water and plant roots
<br />MINESOIL GENESIS AND CLASSIFICATION 597
<br />III. TEXTURE
<br />Minesoil textures vary from site to site depending upon the parent material
<br />from which the soil is developing. Many are similar to textures of the surround-
<br />ing undisturbed soils, but some differ because different textured overburden has
<br />been substituted for the native soil materials. Textures vary from sandy to clayey,
<br />but most minesoils in the eastern and midwestem states are loamy (Bussler et al.,
<br />1984; Ciolkosz et al., 1985; Daniels & Amos, 1981; Indorante & Jansen, 1981;
<br />Short et al., 1986a; Thurman et al., 1985). Some minesoils in the northern Great
<br />Plains are loamy (Schafer et al., 1980), but others are clayey (>40% clay) (Mer-
<br />rill et al., 1980; Sandoval et al., 1973). In eastern Texas, most minesoils are devel-
<br />oping in materials of the Wilcox Group and are fine - loamy, fine -silty or clayey
<br />and commonly have a higher silt content than native soils (DeMent et al., 1992;
<br />Dixon et al., 1980).
<br />IV. ROCK FRAGMENTS AND BRIDGING VOIDS
<br />Although not all minesoils contain rock fragments ( >2 mm) ( Daniels et al.,
<br />1992; Strain & Evans, 1994), minesoils developing on lands mined for coal often
<br />have a greater rock fragment content than the surrounding native soils (Bussler et
<br />al., 1984; Thurman & Sencindiver, 1986). Some minesoil horizons have up to
<br />70% or more rock fragments (Ciolkosz et al., 1985; Daniels & Amos, 1981).
<br />Ashby et al. (1984) summarized research data for minesoils in six states and
<br />showed that rock fragment contents ranged from 32 to 67 %. Some of these rock
<br />fragments are weakly cemented and weather into sand, silt, and clay sized parti-
<br />cles in a few decades.
<br />Bridging voids are commonly associated with these rock fragments (Ciolkosz
<br />et al., 1985; Roberts et al., 1988b; Smith & Sobek, 1978). These voids form because
<br />overlapping rock fragments do not allow all spaces to be filled with fine -earth mate-
<br />rial during the backfilling process. Bridging voids may range from a few millimeters
<br />in diameter to as big as 0.5 m (Ciolkosz et al., 1985) and are uncommon in undis-
<br />turbed soils. These voids may improve aeration and reduce the water- holdifig capac-
<br />ity in some minesoils, but could enhance plant available water by providing small
<br />reservoirs of low tension water in other minesoils (Ammons, 1979) . Voids also could
<br />lead to differential settling. They greatly complicate internal water movement pat-
<br />terns where significant rock fragments are present, and further studies need to be
<br />conducted before specific interpretations of their hydraulic effects can be made.
<br />V. COLOR
<br />Many minesoils have mixed colors or mottling not associated with pedo-
<br />genic horizonation (Smith & Sobek, 1978). As many as eight colors have been
<br />described in some minesoil horizons (Thomas & Jansen, 1985). Gray (low
<br />chroma) colors often are described in minesoils but their presence is not neces-
<br />sarily related to current redoximorphic processes (DeMent et al., 1992; Schafer et
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