Post-mining Land Research Articles

Completion criteria - Case studies considering bond relinquishment and mine decommissioning: Western Australia

ABSTRACT The Western Australia Government Agencies controlling environmental bond assessment and land relinquishment after mine decommissioning advocate proactive environmental management. Meeting environmental objectives ensures return of bond monies and facilitates release of the Company from environmental obligations. Completion criteria that confirm establishment of a self-perpetuating and resilient vegetation cover over mine waste are being developed. Post-mining land use generally reverts to maintaining the natural ecosystem or rangeland. Within this climatic zone very distinct vegetation communities are closely linked to soil substrate classification. Matching surface waste characteristics from a mine waste dump with those of surrounding analogue communities is the first step in determining an achievable vegetation cover. Examples of the methodology as applied to one Western Australian mine site, a semi-arid location (annual rainfall 320 mm) (Westonia - 31°18'S, 118°42'E) is presented. There has, at Westonia, been establishment of Eucalypt Woodland on mildly saline waste surfaces. The combination of direct seeding at the appropriate sowing time and good topsoil management, has led to successful revegetation of a suite of species with all life forms represented.

The Nutritive Value and Yield of Alfalfa Cultivated on Sulphur Postmining Lands

The study was carried out on the reclaimed lands of a bore‐hole sulphur mine. The cropping of two succeeding cuts of alfalfa (Medicago sativa L.) was determined and its chemical composition was analyzed. Alfalfa was cultivated on waste lime (flotation tailings), enriched with a humus layer. The levels of basic nutrients, total S, total F, Ca, P, Mg, K, Na, Fe and Mn were determined in alfalfa. The biomass of an average crop was 6830 kg ha–1 in the first cut and 14300 kg ha–1 in the second one. The yields of dry matter as well as of crude and true proteins were positively correlated with the phosphorus level in the dry matter of alfalfa (P < 0.01). The level of total sulphur was positively linearly correlated with the phosphorus content (P < 0.01). No harmful accumulation of sulphur or fluoride was observed. A deficiency of phosphorus in alfalfa and an abnormal Ca:P weight ratio was found. The S total level was positively correlated with N total concentration. (P < 0.01). The percentage of true protein in crude protein was negatively correlated with total sulphur (P < 0.01). The level of nonprotein nitrogen compounds was positively correlated with S total level (P < 0.01).

Mine decommissioning: Environmental completion criteria for gold and nickel mine waste dumps in arid regions of Western Australia

ABSTRACT The Western Australia Government Agencies controlling environmental bond assessment and land relinquishment after mine decommissioning advocate proactive environmental management. Meeting environmental objectives ensures return of bond monies and facilitates release of the Company from environmental obligations. Completion criteria which confirm establishment of a self-perpetuating and resilient vegetation cover over mine waste are being developed. Quantitative assessment of ecological processes is the basis for development of completion criteria, and includes plant cover, revegetation density, species richness, and reproductive potential. Field sites are in arid ( desert: summer and more effective winter rainfall) and semi-arid ( semi-desert: Mediterranean) regions of Western Australia on Crown Land, with all but one being on pastoral (rangeland) leases. Post-mining land use generally reverts to maintaining the natural ecosystem or rangeland. Within this climatic zone very distinct vegetation communities are closely linked to soil substrate classification. Matching surface waste characteristics from a mine waste dump with those of surrounding analogue communities is the first step in determining an achievable vegetation cover.

Shelf life of stock-piled topsoil of an opencast coal mine

Topsoil is essential to abandoned mines and has to be stock-piled separately for post-mining land reclamation. If the storage period exceeds the 'shelf life' of the topsoil, it cannot be preserved by technical reclamation only. Opencast coal mining production in India is predicted to increase from the present level of 180 million tonnes per year to approximately 256 million tonnes per year by the year 2000. At that time about 60 km2 of land per year would be damaged by direct coal mines and 75 km2 per year would be affected by external overburden dumps and topsoil dumps. A large opencast coal mine was studied to evaluate the effect of stock-piling topsoil. Soil characteristics of soil dumps of six different ages (1, 3, 4, 6, 9 and 10 years old) were compared with those of surrounding unmined sites. Soil profiles were found to change greatly with age. Physico-chemical characteristics of soil dumps were found to deteriorate with respect to unmined soil. It was observed that, as the age of soil dumps increased from one to 10 years, the concentrations of suitable plant growth nutrients in soil gradually decreased and, after six years, the soils were found to be stagnant. This may be considered to be the 'shelf life' of topsoil. Biological reclamation must be adopted to preserve the topsoil if the storage period exceeds the shelf life period. The methodology provides guidelines for assessing the shelf life of topsoil in other areas.

LIVESTOCK GRAZING FOR MANAGEMENT OF RECLAIMED LAND AT NAVAJO MINE: ANIMAL RESPONSE

Livestock responses dining grazing of reclaimed land were monitored at the Navajo Mine since 1994. The Navajo Mine Grazing Management Program (GNP) began in 1991 to prepare for bond release and return of reclaimed land to the Navajo Nation by demonstrating the ability of the land to sustain the post-mining land use of livestock grazing. Local Navajos, whose livestock are used in the GMP, are interested in the ability of the land to sustain their livestock. Sustainable livestock grazing implies the ability of animals to thrive, successfully reproduce and maintain the health of the land. Daily care and monitoring of livestock health was carried out by herders hired by the mining company. General animal health parameters including blood selenium levels were monitored quarterly. Livestock responses to grazing reclaimed land have been largely positive. Cows have produced healthy offspring and owners indicate satisfaction with calf size, and overall performance of the cows. Selenium and other blood testing parameters indicate no adverse effect on animal health to date. Hazards associated with reclamation and ongoing mining activities are important considerations for lands being reclaimed for livestock grazing as a post-mining land use and must be monitored carefully during any grazing program. Preliminary resultsmore » indicate that planned grazing by cattle on reclaimed land at Navajo Mine is feasible and does not adversely affect animal health.« less

VALUE OF COMMERCIAL FORESTRY AS A POST-MINING LAND USE

Forestry is becoming the preferred post-mining land use in the Appalachian region for the landowner as the value of forests becomes recognized. During the summer of 1996, a study was conducted in a white pine (Pinus strobus L.) plantation that was established in 1978 on a pre-SMCRA bench located in Wise County, Virginia. The objectives of this study were to illustrate the feasibility of commercial forestry as a post-mining land use, and to identify relationships between tree productivity and mine soil physical properties. The spoil was a deep, non-compacted, slightly-acid. weathered sandstone that had no topsoil applied. A timber inventory of the plantation showed that it was overstocked, therefore the plantation was thinned down to 20 m{sup 2} ha{sup -1} (90 ft{sup 2} of basal area per acre). The average tree height was 14.3 in (47 ft), translating to a very high site index of 35 in (110 ft; base age 50), compared to site indices of 24 in (80 ft) and 18.3 in (60 ft) for adjacent undisturbed forest soils and post-SMCRA reclaimed mine soils, respectively. When these site indices were used to project tree growth for 30 years, the estimated timber per-acre value was $3,480, $1,755, and $122more » for the non-compacted mine soil, undisturbed forest soil, and typical post-SMCRA mine soil, respectively. The twenty-fold difference in the timber value between the non-compacted none soil and the typical post-SMCRA mine soil represents a tremendous lost opportunity. for most post-SMCRA sites that are not reclaimed for commercial forestry. The high productivity of the white pine plantation growing on the pre-SMCRA bench was attributed to low soil bulk density and a moderately-acid sandstone mine soil. Reclamation practices that result in these desirable soil properties need to be encouraged, so that restored forest land will be profitable for the landowner, meet society`s needs, and meet the spirit and letter of the SMCRA.« less

ACHIEVING OPTIMUM POST MINE RECLAMATION RESULTS THROUGH COMPUTER AIDED DESIGN

Recent technological advances have made it possible to map and model disturbed mine areas to plan the most cost effective manner in which to reclaim post mine land. The process not only can reduce the cost to reclaim each acre, but also enhances regulatory compliance. Results from a 21 acre test at Texas Utilities Mining Company`s Martin Lake-Oak Hill Mine have shown a significant reduction in dozer hours per acre to complete reclamation. A larger, more conclusive project has been completed at TUMCO`s Monticello-Winfield North Mine. The new project includes approximately 350 acres of the C-Area final pit. Results of this project have resulted in substantial cost savings versus conventional reclamation planning methods.

LIVESTOCK IMPACTS FOR MANAGEMENT OF RECLAIMED LAND AT NAVAJO MINE: VEGETATION RESPONSES

The post-mining land use for Navajo Mine, a large surface coal mine in northwest New Mexico, is livestock grazing. Reclamation began in the early 1970`s and has been primarily directed toward the development of a grassland with shrubs. However, none of these lands were grazed before 1994 and none have been released back to the Navajo Nation. Therefore, it is not known how these reclaimed lands will respond to livestock impacts once the lands are released. Livestock impacts include grazing, trampling, and adding feces and urine. Cattle impacts were applied in 1994 to a land that had been reclaimed in 1978, 1991 and 1992. Vegetation monitoring procedures were implemented to detect and document successful and unsuccessful impact practices for both impacted areas and areas excluded from cattle. After three impact seasons, there were similar levels of perennial plant cover, production, and density on impacted lands compared to excluded lands. Based on age structure analysis, there is a trend that establishment of seedlings is stimulated by cattle. Cattle also decrease the amount of previous years` growth of standing phytomass with a trend to stimulate new growth. It is possible that some of the previous year`s growth was reduced by cattle tramplingmore » as much as by grazing because cattle generally prefer to eat the current year`s growth before it cures. No differences in number of seedheads per plant, animal sign, plant pedestals, and soil rills could be detected after three seasons of impacting.« less

Survival of Three Tree Species on Old Reclaimed Surface Mines in Ohio

Early studies of mine reclamation emphasized trees for revegetating minesoils. Scientists of the USDA Forest Service transplanted four tree species in 1946 into leveled or unleveled overburden near Georgetown, OH, and into unleveled overburden near Dundee, OH. Black locust (Robinia pseudoacacia L.) had good initial survival on both sites but died in later years due to locust borers (Megacyllene robiniae). Survival and growth of remaining white ash (Fraxinus americana L.), white pine (Pinus strobus L.), and yellow-poplar (Liriodendron tulipifera L.) were determined and soil properties examined on both sites in 1992. Minesoil bulk density in Georgetown leveled areas was similar (1.1 to 1.2 Mg/m3) to unleveled areas in 1992. Minesoil pH was 7.7 and no nutrient deficiencies were found. Bulk density at Dundee was 1.1 Mg/m3 and minesoil pH was 4.2 with high exchangeable acidity, Al, and Fe concentrations. White ash had the best survival after 46 yr, averaging 43% in both leveling treatments at Georgetown and 33% at Dundee. White pine survival averaged 22% at Georgetown and 14% at Dundee. Yellow-poplar had poor survival (3%) on Georgetown leveled areas, 21% survival on Georgetown unleveled areas, and 17% survival at Dundee. White pine and yellow-poplar trees were 4 to 6 m shorter on Georgetown leveled areas vs. unleveled areas. White ash height was similar between leveling treatments and no height differences were seen for any species between Georgetown unleveled and Dundee. Volume for yellow-poplar ranged from 39 m3/ha on the Georgetown leveled area to 350 m3/ha on unleveled areas. Volumes roughly paralleled survival for white pine and yellow-poplar. Thirteen volunteer tree species were identified and they averaged 20% total tree basal area across the three areas. Maple (Acer sp.) and elm (Ulmus sp.) were two common volunteer trees. After 46 yr, these areas support a closed canopy of commercially valuable trees, providing soil stabilization, potential economic returns, and wildlife habitat. Eastern U.S. surface mine reclamation should emphasize tree planting and forests as postmining land uses. White ash is recommended on leveled or unleveled sites with alkaline or acidic minesoils.

INFLUENCE OF GRADING INTENSITY ON HERBACEOUS GROUND COVER, EROSION, AND TREE ESTABLISHMENT IN THE SOUTHERN APPALACHIANS

In the southern Appalachian coalfields of Virginia, southern West Virginia and eastern Kentucky, the opportunity exists to create productive forests capable of providing good timber management opportunities on surface mined land. Unfortunately, this opportunity is seldom realized, in part because minesoil compaction caused by excessive surface grading hinders tree establishment and long-term tree growth. This five-year study was established in eastern Kentucky to evaluate the effect of several surface grading treatments on minesoil erosion, herbaceous ground cover development, and tree survival and growth. Three grading treatments were each replicated three times on a 40% slope. The treatments were (1) the operational {open_quotes}intensive{close_quotes} grading practice used by the operator, (2) a more {open_quotes}moderate{close_quotes} grading, and (3) a {open_quotes}ripped{close_quotes} treatment that created a rough surface. During the course of the study, the intensive graded treatment had the greatest erosion and the poorest ground cover development and tree growth. This traditional practice of intensive surface grading to create a smooth surface is not only unnecessarily expensive but, as this study clearly indicates, compaction caused by grading can have detrimental effects for environmental quality (erosion) and forest productivity. When forestry is the post-mining land use, grading practices should be minimized to leave minesoil inmore » a loose condition to reduce erosion and increase tree growth.« less

Shrub Preference and Utilization by Big Game on New Mexico Reclaimed Mine Land

Mined lands are reclaimed so the land can be used for other purposes after mining. At the La Plata Mine in New Mexico, post-mining land uses include livestock grazing and providing wildlife habitat. The objective of this research was to evaluate use of seeded and volunteer shrubs by mule deer (Odocoileus hemionus) and elk (Cervus canadensis) during the first opportune season, which occurred 7 years following reclamation. Twelve species of shrubs (10 planted and 2 volunteer) were found on 4 different topdressing treatments. Five branches of shrubs for each species were marked and lengths measured prior to and following the winter wildlife grazing season to determine amount of use. Greatest use by both deer and elk was on curlleaf mountain mahogany (Cercocarpus ledifolius Nutt.), followed in decreasing order by fourwing saltbush (Atriplex canescens [Pursh] Nutt.), rubber rabbitbrush (Chrysothamnus nauseosus [Pall.] Britton), common winterfat (Ceratoides lanata [Pursh] Moq.), shadscale (A triplex confertifolia [Torr. and Frem.] Wats.) , antelope bit terbrush (Pursia tridentata [Pursh] DC.), big sagebrush (Artemisia tridentata Nutt.), skunk bush sumac (Rhus trilobata Nutt.), Utah juniper (Juniperus osteosperma [Torr.]Little), fringed sagebrush (Artemisia frigida Willd.), service berry (Amelanchier alnifolia Nutt.), and pinyon pine (Pinus edulis Engelm.). The greatest shrub utilization was on the Jocity topdressing treatment, which is the name of the soil series from which the topdressing was obtained. The Jocity soil series was found on a flood plain site dominated by greasewood (Sarcobatus vermiculatus [Hook.] Torr.). Other shrub utilization, in decreasing order of use, was on topdressing that was a mixture of Jocity and Atrac topdressing, spoil topdressing, and Atrac topdressing, which is a soil series found on an upland site dominated by big sagebrush.

Wildlife Management, Surface Mining, and Regional Planning

ABSTRACT Wildlife management, surface mining, and regional planning historically have had conflicting missions. The cooperative public/private venture which created the Robinson Forest and Cyprus‐Amax Wildlife Management Areas is presented as an example of how a regional perspective encourages a symbiotic relationship among these Functions. Wildlife management areas, as either an interim or final land use. are shown to incorporate development concepts which benefit the general public, the coal industry, and the environment. Examining the regional pattern or wildlife management areas and refuges confirms the appropriateness of the subject site for this use. It is suggested that the pattern of mined lands can be studied to identify other sites with potential to provide linkages between wildlife habitat areas and encourage reclamation of such sites to the “fish and wildlife” postmining land use. Such reclamation strategies should be pursued within a long‐term planning framework. More research is needed to recreate specific habitat types on drastically disturbed land and planning is needed to assure that sensitive habitats or species arc located away from zones likely to undergo future development. Use of geographic information systems to integrate existing environmental information could make such studies more effective.

Application of a Watershed Computer Model to Assess Reclaimed Landform Stability in Support of a Reclamation Liability Release

The Surface Mining Control and Reclamation Act of 1977 (SMCRA) instituted specific requirements for surface coal mine reclamation that included reclamation bonding and tied release of liability to achieving acceptable reclamation standards. Generally, such reclamation standards include successfully revegetating the site, achieving the approved postmine land use and minimizing disturbances to the prevailing hydrologic balance. For western surface coal mines the period of liability continues for a minimum of 10 years commencing with the last year of augmented seeding, fertilizing, irrigation or other work. This paper describes the methods and procedures conducted to evaluate the runoff and sediment yield response from approximately 2,700 acres of reclaimed lands at Peabody Western Coal Company`s (PWCC) Black Mesa Mine located near Kayenta, Arizona. These analyses were conducted in support of an application for liability release submitted to the Office of Surface Mining (OSM) for reclaimed interim land parcels within the 2,700 acres evaluated.

Influence of microsites on redevelopment of vegetation on coalmine spoils in a dry tropical environment

An age series of mine spoils (5, 10, 12, 16 and 20 years old) in a dry tropical environment was studied to assess the impact of different microsites (substrate conditions) on physico-chemical and biological characteristics of spoils, and on species composition and plant biomass levels. Impact of microsites, even after 20 years of soil and vegetation redevelopment, remained important. Undulating surface and flat surface microsites showed more or less a similar behaviour after 20 years of succession and were better habitats than slope and coalpatch margin microsites for plant growth. The present study indicated that microsite conditions should be taken into consideration in any revegetation programme and desired natural colonizing species of even higher successional order may be used to accelerate the natural revegetation process according to the post-mining land use objectives.

Runoff Curve Numbers for Reclaimed Surface Mines in Pennsylvania

The Surface Mining Control and Reclamation Act of 1977 requires evaluation of pre‐ and postmining hydrology for design of runoff and sediment control structures on mined land. The runoff‐curve‐number (CN) method as developed by the Soil Conservation Service has been routinely used to predict rainfall‐runoff relationships for ungauged watersheds disturbed by surface mining and reclamation. However, lack of sufficient rainfall‐runoff data from reclaimed surface mines in the Eastern United States has prevented accurate calibration of CN values for those areas. Median CN values calculated from rainfall‐runoff data from reclaimed surface mines in central Pennsylvania indicate that the currently accepted methods for estimating CN values underestimate total runoff from the standard design storm by as much as 50%. Median CN values range between 83 and 88 with CN values as high as 99 for soils with antecedent moisture condition classification III. It is recommended that hydrologic soil group D be adopted for sandy‐loam and silty‐loam postmine soils and used with the appropriate postmine land use to calculate CN values for reclaimed‐surface‐mine watersheds.

Natural Revegetation of an Unreclaimed Lignite Surface Mine in East-Central Texas

Evaluating plants and soils on unreclaimed surface mines helps land managers un- derstand the effects of minesoil properties on plant growth and community development and may aid in the development of current reclamation plans. Eight unreclaimed surface mined sites in east-central Texas, ranging in age from 3 months to 50 years, were sampled to evaluate vegetation and minesoil changes over time and for comparison to an adjacent unmined area. Three- and 6-month-old unre- claimed areas had about 1% plant cover composed of pioneer grass and forb genera, including Di- chanthelium, Aster, Chenopodium, and Polygonum. Herbaceous plant cover increased from 12% on the 5-year-old site to a peak of 25% on the 20-year-old site. Dominant genera on 10- to 20-year-old sites were Andropogon, Bothriochloa, Cynodon, Dichanthelium, Paspalum, Aster, and Rumex. Woody species established as early as 5 years after mining (predominantly Baccharis salicina T. et G.), and canopy cover reached 14 and 35% on the 20- and 30-year-old sites, respectively. On the 50-year-old site, 17 woody species formed a multilayered vegetation structure with > 100% cover. Bulk density of minesoils in the surface 12 cm declined with time from 1.30 to <1.00 Mg/m3 as vegetation and litter increased. Undisturbed soils had an average pH of 5.9. Minesoil pH decreased from 6.9 on 3- and 6-month- old sites to 3.8 on 5- to 30-year-old sites (due to pyrite oxidation) and increased to 6.8 on the 50- year-old site. Several grass and forb species found on acidic minesoils in this study may be good candidates for low input revegetation programs for other postmining land uses.

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.

Generating productive topsoil substitutes from hard rock overburden in the southern appalachians

Natural soils on steeply sloping landscapes in the Appalachian coal fields of Virginia. West Virginia. Kentucky, and Tennessee are often thin, rocky, acidic and infertile, making the topsoiling of surface mined sites impractical in many cases. Topsoil substitutes composed of blasted rock fragments are commonly used in this region. The proper selection and placement of designated topsoil substitutes is therefore critical to long term reclamation success. These mine soil surfaces are not in equilibrium and with the surface environment, and it is quite difficult to diferentiate among dissolution, adsorption, desorption and precipitation reactions as these surfaces weather with time. Severe compaction limits the productivity of many otherwise suitable topsoil substitutes. A minimum non-compacted thickness of 1 m is desirable to insure long run mine soil productivity for a variety of post-mining land uses. Significant changes in the physical, chemical, and mineralogical properties of mine soils occur within one year after placement. Mine soils high in silt content often form hard vesicular surface crusts, particularly when left unvegetated. The long term survival of plant communities on these mine soils is dependent upon mine soil organic matter accumulation and N and P cycling. Little is currently known about N and P dynamics in these mine soils, but P-fixation is a profound problem in high Fe(3-) spoils. Revegetation practices that were designed to meet 2-year bond release requirements may not he sufficient to meet new 5-year release standards. Hard rock derived mine soils can often equal or exceed native topsoil in productivity and post mining land use potential.

Reactivation of Landslides by Surface Subsidence from Longwall Mining: ABSTRACT

Subsidence research by the U.S. Bureau of Mines has identified and documented the occurrence of landslides over a longwall mining area in the Dunkard basin. Most of these landslides occurred in masses of slumped hummocky soil generally associated with limestone and claystone beds of the Washington and Greene Formations. Identification and characterization of this phenomenon are needed to model accurately the future effect of subsidence-related surface damage to postmining land use. Mining by longwall methods has been observed to produce a gradual surface subsidence profile of up to 60% of the thickness of the mined coal bed. The gradual subsidence of panels averaging 600 × 5,000 ft (180 × 1,525 m) can cause reactivation of older landslide deposits by decreasing the support to the landslide toe area. Examination of surficial features over a longwall mining area comprised of nine panels has led to the identification of several reactivated landslides. The two largest landslides occurred above a thin sandstone member with several associated springs. The largest landslides ranged from 100 to 300 ft (30 to 90 m) in length and from 100 to 200 ft (30 to 60 m) in width. Maximum scarp-slope displacements were approximately 7 ft (2 m). Less significant mass wasti g was also observed over the longwall panels. Identification of landslides was accomplished through examination of premining aerial photographs and geologic field investigation. Characterization of reactivated zones was achieved through evaluation of current aerial 2-ft (0.6-m) surface contour map and field surveys. Recognition of problem areas will make civic and mining personnel aware of the landslide potential so that damage in such areas can be minimized. End_of_Article - Last_Page 1921------------