Richard Sweigard

SURFACE MINE REFORESTATION RESEARCH: EVALUATION OF TREE RESPONSE TO LOW COMPACTION RECLAMATION TECHNIQUES 1

In 1996, a multidisciplinary group of researchers at the University of Kentucky initiated a study on the Starfire surface mine in eastern Kentucky to evaluate the effects of soil compaction and two organic amendments on the survivability and growth of high value tree species. Three types of prepared rooting medium were examined: compacted spoil, lightly compacted spoil, and uncompacted spoil. The compacted spoil was prepared using normally accepted spoil handling techniques that resulted in a smooth graded surface. The lightly compacted spoil was loose-dumped and struck-off with one or two passes of a bulldozer. The uncompacted spoil was loose-dumped and not further disturbed. In addition, organic amendments (mulches) were evaluated within the three reclamation techniques. The organic amendments used were processed hardwood bark mulch and a combination of straw and horse manure mulch. The following six species of trees were planted: white oak (Quercus alba), white ash (Fraxinus americana), eastern white pine (Pinus strobus), northern red oak (Quercus rubra), black walnut (Juglans nigra), and yellow poplar (Liriodendron tulipifera). Five of the six species, the exception being white ash, showed increased survivability as compaction was minimized. Additionally, the loose-graded techniques led to enhanced growth in height for the seedlings. The addition of organic amendments also showed additional benefit but results varied by species and by treatment. Results definitively show that strike-off and loose-dump techniques improve seedling height and survival. The data also suggest that even a small amount of traffic (i.e., one or two passes per the strike-off method) may result in enough compaction to significantly reduce survival and growth in some species, such as yellow poplar and white pine. In the backfilling and grading process, spoil material should be placed and compacted according to standard engineering practices so that the required stability and approximate original contour is achieved. However, the top 1.2 to 1.8 meters (4 to 6 feet) of material should not be graded or only lightly graded so that it is as uncompacted as possible.

EVALUATION OF LOW SPOIL COMPACTION TECHNIQUES FOR HARDWOOD FOREST ESTABLISHMENT ON AN EASTERN KENTUCKY SURFACE MINE

To return surface mined areas in eastern Kentucky to productive forests, the compaction of mine spoil must be minimized or ameliorated. Four methods to reduce compaction on reclaimed surface mines were compared at the Bent Mountain research site in Pike County, Kentucky. The methods included: single shank ripped spoil, triple shank ripped spoil, excavated spoil, and rough graded spoil. Normally graded spoil was also examined as a control to represent a traditional reclamation practice. A single shank ripper was used in gently sloping areas to a depth of ≈ 2-m, while the triple shank ripper was used primarily on level spoil to a depth of ≈ 1.5-m. Both rippers were pulled with a D-11 dozer. Excavated spoil was created by digging out compacted spoil to a depth of ≈ 1-m and dropping it in place. The end dump or rough graded spoil was created by dumping mixed sandstones and shale spoil from a dump truck to a depth of 2 to 2.5-m followed by minimal grading (single pass) with a D-9 dozer to strike-off the piles. All sites were planted with native hardwood species in 2004. Three plots measuring 50 x 50-m were established within each spoil treatment. All trees within the research plots were tagged and have been examined each year for survival and growth characteristics. Bulk density was also measured annually using a nuclear density probe. Preliminary results show several statistically significant differences in tree height and survival. Survival for white oak (Quercus alba) was significantly higher for all reclamation methods compared to the control, and end dump was significantly higher than excavated. Green Ash (Fraxinus pennsylvanica) height was significantly greater for all reclamation methods compared to the control, and single shank ripped was significantly higher than all methods. For black locust (Robinia pseudoacacia) height and northern red oak (Quercus rubra) survival all methods except excavated were significantly greater than the control. Additional

The impact of surface applied mulches on selected physical properties of reclaimed mountaintop removal sites

Much of the land reclaimed since enactment of the 1977 Surface Mining Control and Reclamation Act is over-compacted. Excessive compaction in replaced growth media is detrimental to establishment of trees. If trees are to be grown on reclaimed sites, excessive compaction must be alleviated. Dry bulk density and penetration resistance can be used to indicate the level of compaction in replaced growth media. The University of Kentucky has developed reclamation test cells at a surface mine to determine the impact of organic soil supplements on selected soil physical properties of reclaimed sites. The organic soil supplements being evaluated include hardwood bark and straw and manure. Data were collected at the test cells for dry bulk density, maximum penetration depth and penetration resistance. The data show no statistical evidence that applying organic supplements has a major effect on selected soil physical properties in replaced growth media.

FIELD INVESTIGATION OF BEST PRACTICES FOR STEEP SLOPE MINE RECLAMATION EMPLOYING THE FORESTRY RECLAMATION APPROACH

Previous research has demonstrated that excessive compaction of reclaimed surface mined land is a major deterrent to successful reforestation. The five step Forestry Reclamation Approach (FRA) was developed, in part, to address this problem. In particular, the FRA emphasizes the need for creating a suitable rooting medium that is at least four feet deep and free of compaction. However, most of the prior reforestation research has been conducted on land that was flat or gently rolling. Some concern has been expressed about applying the FRA to steep-slope mines, such as those found throughout the Appalachian region. A field study was conducted at ICG’s Peel Poplar Mine in eastern Kentucky to evaluate the applicability of the FRA to steep-slope mining. The evaluation was based upon operational efficiency, economics, slope stability, and reforestation potential. Specifically, a 4.7 acres area was reclaimed with a combination of loaders, trucks, and dozers. Final grading was completed using single pass of a CAT-D11 dozer. Slope movement was monitored periodically by surveying 70 steel rebars. Soil bulk density, penetration resistance, and tree survival were also measured. As the project nears its end, the slope has not exhibited any appreciable instability and the FRA appears to have been effective in reclaiming the land to a forested condition. Additional key words: Forestry reclamation, loose grading, bulk density, penetration resistance, growing media _______________________________ 1 Paper was presented at the 2010 National Meeting of the American Society of Mining and Reclamation, Pittsburgh, PA Bridging Reclamation, Science and the Community June 5 11, 2010. R.I. Barnhisel (Ed.) Published by ASMR, 3134 Montavesta Rd., Lexington, KY 40502. 2 Dr. Richard J. Sweigard is an Associate Dean of Engineering for Administration and Academic Affairs, University of Kentucky, Lexington, KY-40506. Dharmendra Kumar is a Research Assistant, Department of Mining Engineering, University of Kentucky, Lexington, KY-40506. Proceedings America Society of Mining and Reclamation, 2010 pp 1258-1273 DOI: 10.21000/JASMR10011258

TREE GROWTH AND NATURAL REGENERATION ON THREE LOOSE- GRADED SURFACE MINE SPOIL TYPES IN KENTUCKY: PRELIMINARY FINDINGS 1

Reforestation research on mined lands has shown that loosely graded topsoil, weathered sandstone and/or other non-toxic topsoil substitutes are suitable growing media for establishing native forests in Appalachia. Reclamation practitioners however, have expressed confusion as to what constitutes the best available material other than topsoil. Six research plots were established on a surface mine for the purpose of evaluating the influence of three different loose- graded spoil types on tree performance. The three spoil types are: (1) predominately brown weathered sandstone; (2) predominately gray un-weathered sandstone; and (3) mixed weathered and un-weathered sandstones, and shale material (mine-run spoil). The total area of each plot is approximately 4,050 square meters (one acre). Four species of tree seedlings were planted into the spoils. Growth and survival of the planted trees were evaluated for two years. As an indicator of natural succession potential, percent ground cover of volunteer vegetation on the three spoil types was also evaluated. Preliminary observations indicated that by the second year (2006) after planting, the gray plots had an overall higher average survival (96%) than the mixed (84.5%) and brown plots (83%). The brown sandstone plots however, showed significantly more growth in height and diameter than the gray and mixed plots. Ground cover from natural regeneration was found to be 42.3 percent on the brown plots (40 different species), 2.6 percent on the mixed plots (21 different species), and less than 1 percent on the gray plots (6 different species).

CARBON SEQUESTRATION ON SURFACE MINE LANDS

A major effort this quarter was to inventory all the planted areas to evaluate the diameter and height growth as well as determine survival rates. Soil bulk density and compaction continue to be evaluated on all the areas to determine the effects on tree growth and survival. The hydrologic quantity and quality are continuously monitored and quantified. Much effort was also expended in preparing technical presentations for professional meeting and for the preparation of the final project report.

Characterisation of fly ash and bottom ash from a coal-fired power plant

ABSTRACT Fly ash and bottom ash are by-products of coal-fired power plants. They are coal combustion wastes and can contain many chemical elements that may be potentially harmful to the environment. Although some of the ashes are used as construction materials, most of them are still disposed of in settling ponds or landfills. The chemical and physical characteristics of typical fly ash and bottom ash are summarized. In order to determine how well these typical values describe the ash from a specific plant, both types of ashes from a coal-fired power plant in Kentucky were characterized. These values were then compared to the values reported in the literature. The effect of ash disposal upon groundwater was also investigated for the specific plant

An economic evaluation of soil bioengineering as a method for slope stability on abandoned mine land in Eastern Kentucky

ABSTRACT Unstable slopes are a serious problem on abandoned mine land (AML) in Kentucky and a number of other states. Current practices used to manage unstable slopes rely on modern conventional techniques that incorporate rock, concrete, or steel structural components. Implementation of these techniques has proven expensive due to recurring maintenance requirements. This study examines soil bioengineering technology as a viable alternative. In this study, the cost effectiveness of two common slope stabilization systems— rock gabions and rock riprap—has been compared with the innovative soil bioengineering system. Baseline cost estimates applied to all three systems were consistent with commercial scales. Assuming a useful life of 20 years for both the gabion and riprap systems, sensitivity analysis using net present values (NPV) in response to changes in both installation costs (I) and useful life (N) was conducted on both systems. Data was calculated over a range of applicable interest rates. The result...

Reclamation of surface-mined land for agricultural use

ABSTRACT Current reclamation standards require surface mine operators to address many difficult issues, not the least of which is the selection of an appropriate postmining land use plan. When it is determined that this plan should include cropland, there are some specific problems that must be resolved. The planning process is reviewed and specific recommendations are made. Techniques for soil removal and replacement are compared. If soil compaction is excessive, deep tillage is recommended to alleviate the problem. Differential settlement is another problem that may be encountered. It can be prevented, to a degree, by avoiding the creation of a completely level ground through final grading. If it does occur, procedures are available to correct the problem. Revegetation follows standard agricultural practices.

CARBON SEQUESTRATION OF SURFACE MINE LANDS

The January-March 2004 Quarter was dedicated to tree planting activities in two locations in Kentucky. During year one of this project there was no available mine land to plant in the Hazard area so 107 acres were planted in the Martin county mine location. This year 120 acres was planted in the Hazard area to compensate for the prior year and an additional 57 acres was planted on Peabody properties in western Kentucky. An additional set of special plots were established on each of these areas that contained 4800 seedlings each for special carbon sequestration determinations. Plantings were also conducted to continue compaction and water quality studies on two newly established areas as well as confirmed measurements on the first years plantings. Total plantings on this project now amount to 357 acres containing 245,960 tree seedlings.