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Coal Surface Mining and Reclamation

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Land Reclamation

by J. E. Welch

Method

The method used by the Clemens Coal Company in reclaiming the mined land included the following procedures:

  1. Spoil banks leveled and area smoothed with a bulldozer to a gently rolling terrain allowing for needed drainage.
  2. Lime applied by conventional lime-spreading truck (half of total applied).
  3. Field tilled deeply (10-12 inches) with an offset (Rome) disc.
  4. Field dragged with a 20-foot steel I-beam.
  5. Lime applied by conventional lime-spreading truck (half of total applied).
  6. Field tilled with standard farm disc to approximately 6 inch depth.
  7. Additional dragging and mechanical picking of field to remove large rock fragments from the surface.
  8. Seed bed prepared with farm disc and harrow.
  9. Field planted to wheat at the rate of 90 lbs/ac or wheat and fescue at the rate of 90 and 20 lbs/ac and fertilized with 70 pounds of nitrogen, 70 pounds of phosphorus (P2O5), and 70 pounds of potassium (K2O) per acre, based on soil-test data (Fig. 14 and Table 31) using a conventional grain drill.
  10. Additional fescue seeded by broadcasting at the rate of 20 lbs/ac.

Leveling to a gently rolling terrain allows usage of conventional farm machinery and grazing of livestock, as well asĀ· adequate drainage. Offset discing results in deeper application of lime, which increases the depth of minesoil acceptable for plant root growth. Dragging the field insures a smooth surface and prepares the surface for tillage equipment. Removing large rock fragments from the surface allows the use of farm machinery, such as the grain drill, without damage. Multiple discing breaks down the shale fragments to finer sizes, increases water infiltration and retention, and improves seed-soil contact.

Figure 14—Map of location of soil samples taken to determine lime and fertilizer application pates. Data from Clemens Coal Company records.

Map of location of soil samples taken to determine lime and fertilizer application pates. Data from Clemens Coal Company records.

Table 31—Soil-test data and lime and fertilizer recommendations.a

Sample pH Available P
(lb/ac)
Exchangeable K
(lb/ac)
Recommendations (lb/ac)
N P2O5 K2O ECCb
Field 1
1 4.8 4 120 50-70 70 70 4000
2 4.7 4 100 50-70 70 70-80 5000
3 5.2 6 80 50-70 70 80 3000
4 4.4 4 110 50-70 70 70-80 6000
5 4.8 4 100 50-70 70 70-80 5000
Field 2
6 4.4 6 190 50-70 70 40-50 7500
7 4.4 4 170 50-70 70 50-60 7500
8 5.0 2 10 50-70 80 100 4000
9 4.8 2 100 50-70 80 70-80 4000
10 4.6 2 140 50-70 80 60-70 5000
11 4.3 2 130 50-70 80 70 6000
Field 3
12 6.6 6 110 50-70 70 70-80 None
13 7.2 4 160 50-70 70 60 None
14 6.9 4 140 50-70 70 60-70 None
15 7.2 6 90 50-70 70 70-80 None
16 5.2 10 150 50-70 60 60-70 3000
(a) Data supplied by Clemens Coal Company; analysis by Kansas State University Soil Testing Laboratory.
(b)Effective Calcium Carbonate in pounds/acre needed to raise soil pH to 6.8 (Woodruff, 1967).

Field Treatments and Crop Yields

Field 1

Mining was completed in 1973. Leveling and smoothing of the spoil banks were completed in the fall of 1974. Numerous depression areas remained after smoothing. During that same fall the field was fertilized with nitrogen, phosphorus, and potassium, and seeded to soft red winter wheat (Arthur 71). Wheat was selected because it is an annual plant species that returns a profit if yields are high, and quickly provides a good ground cover and a root mass to aid in controlling soil erosion. Growth of wheat in the depression areas of the field was poor due to water saturation of the soil, which caused a significant reduction in the amount of oxygen available to plant roots. The field yielded only about 15 bu/ac (bushels per acre). As a result of the mining method of piling overburden onto upper overburden, considerable mixing of the 2 overburdens and soil occurred, which resulted in dark-gray shale fragments containing pyrite (FeS2) being deposited in the surface of 7 to 10 acres in the north part of the field (Pls. 3 and 4). Few wheat plants grew in this area (Pl. 5). Studies in Ohio show the sulfur in dark-gray to black shales located nearest the coal seems to be the major cause of acidity in coal mining areas (Sutton, 1970).

During the early fall of 1975, the depression areas in the field were drained and filled, and the acid areas in the north part of the field were covered with soil. The field was tilled and fertilized with nitrogen, phosphorus, and potassium, and seeded to soft red winter wheat (Arthur 71) and tall fescue (Kentucky 31) in November. The wheat in this instance was planted as a nurse crop to aid in establishing the perennial fescue. Tall fescue lives for a number of years. It dies back to the ground annually, but regenerates itself each growing season. Five tons per acre of agricultural limestone (ECC-6S percent) were also added. A good stand of wheat was produced that yielded about 30 bu/ac, compared to 15 bu/ac the previous year. However, little fescue germinated and that which did showed poor growth.

Plate 3—View of wheat stubble and an excessively acid spot (hotspot) in the northern half of Field 1, August 1975.

View of wheat stubble and an excessively acid spot (hotspot) in the northern half of Field 1, August 1975.

Plate 4—Close-up view of an excessively acid spot (hotspot) in northern half of Field 1 showing acid-producing dark-gray shale fragments and other rock fragments.

Close-up view of an excessively acid spot (hotspot) in northern half of Field 1 showing acid-producing dark-gray shale fragments and other rock fragments.

Plate 5—Aerial view of northern half of Field 1 (Lower right) showing acid areas devoid of wheat, May 1976.

Aerial view of northern half of Field 1 (Lower right) showing acid areas devoid of wheat, May 1976.

Field 2

Mining was completed in 1973. Leveling and smoothing of the spoil banks were completed during the fall of 1974. No other treatments were performed on the field during 1974.

Additional smoothing to bury shale particles and fill in depression areas was done during the spring and summer of 1975, as a result of the poor growth of wheat in Field 1 the previous year. In November 1975 the field was fertilized with nitrogen, phosphorus, and potassium, and seeded to soft red winter wheat (Arthur 71) as a nurse crop to tall fescue (Kentucky 31). Five tons of agricultural limestone (ECC-65 percent) per acre were also applied. A good stand of wheat was produced and yielded about 30 bu/ac (Pl. 6). As was the case in Field 1, little fescue germinated and that which did showed poor growth.

Plate 6—Aerial view of Field 2 (lower right) showing a good stand of wheat with a few low spots devoid of wheat, May 1976.

Aerial view of Field 2 (lower right) showing a good stand of wheat with a few low spots devoid of wheat, May 1976.

Field 3

Mining was completed during the summer of 1974, and leveling and smoothing of the spoil banks were completed during the summer of 1975. In November 1975 the field was fertilized with nitrogen, phosphorus, and potassium. The field was seeded to hard red winter wheat (Early Triumph), in place of the soft red winter wheat (Arthur 71) that had been planted in Fields 1 and 2 (Pl. 7). Based on soil-test data (Table 31), no lime was applied. A fair stand of wheat was produced that yielded about 25 bu/ac (Pls. 8 and 9). This yield compared well with the 30 bu/ac yield of Fields 1 and 2 (wheat planted in the fall of 1975).

Plate 7—View of Field 3 showing surface appearance after seeding, November 1975.

View of Field 3 showing surface appearance after seeding, November 1975.

Plate 8—Aerial view of Field 3 showing a fair stand of wheat with a few low spots devoid of wheat, May 1976.

Aerial view of Field 3 showing a fair stand of wheat with a few low spots devoid of wheat, May 1976.

Plate 9—Close-up view of stand of wheat in Field 3 that yielded about 30 bushels per acre, June 1976.

Close-up view of stand of wheat in Field 3 that yielded about 30 bushels per acre, June 1976.

Field 4

Mining was completed during the summer of 1975 and leveling and smoothing of the spoil banks were also completed during the same summer. In November 1975 the field was fertilized with nitrogen, phosphorus, and potassium, and seeded to hard red winter wheat (Early Triumph) as was done in Field 3. No lime was applied to the field. A poor stand of wheat was produced that yielded only about 10 bu/ac (Pl. 10).

Plate 10—Aerial view of Field 4 showing the overall poor stand of wheat, and the southwest quarter of the field practically devoid of wheat.

Aerial view of Field 4 showing the overall poor stand of wheat, and the southwest quarter of the field practically devoid of wheat.

Field 5

Mining was completed during the summer of 1975. Leveling and smoothing of the spoil banks were also completed that same summer. In November 1975, the field was fertilized with nitrogen, phosphorus, and potassium, and seeded to hard red winter wheat (Early Triumph), as had been done in Fields 3 and 4. No lime was added. A good stand of wheat was produced that yielded about 40 bu/ac.

Conclusions

From comparisons of yield data from the 5 fields, some general conclusions were reached concerning the efficacy of the various procedures added to and deleted from the original land treatment method employed in Field 1 to promote the growth of grass on minesoil.

The higher yield in Field 1 of wheat planted in 1975 compared to that planted in 1974 showed the need for liming to raise the soil pH to a level that would not adversely affect plant growth. Also, the difference in yields showed the need to bury acid-producing shale fragments below the depth of oxidation.

The identical yields of wheat planted in 1975 in Fields 1 and 2 showed the land treatment method to be quite successful in promoting a relatively high yield of wheat. Also, the yields showed that soft wheat will yield high if the pH is raised to a level that does not adversely affect wheat growth. The failure of fescue to germinate and grow after planting in both fields showed the method to be ineffective in promoting the growth of fescue in conjunction with wheat on minesoil. The failure of the fescue to germinate and survive could have been due to planting the seed too deep with the grain drill. Some seeds will not germinate if planted deep, especially if the soil surface crusts over, as it does on minesoils with silty clay loam textures (Barnhisel and others, 1975). Also, in coarse materials such as minesoil, the larger wheat seed will have better contact with soil and hence greater access to soil moisture than will the smaller fescue seed. The growth of tall fescue has been shown to be affected by differences in particle-size distribution (texture) (Van Lear, 1971). In addition, wheat seeds can germinate with little available moisture (Greb and Smika, 1979). Another possibility is aluminum toxicity. Fleming and others (1974) found that 4 mg/l dissolved aluminum severely inhibited tall fescue top and root growth. At around pH 5.5 aluminum concentration in soil solution is increased and greatly exceeds normal background levels in soil solution (Bohn and others, 1979). Wheat has been shown to be high!y tolerant of excessive amounts of aluminum in soil solution (Reid, 1976); however, some plant species cannot tolerate excessive amounts of aluminum and fail to germinate. Some plant scientists think that the seed coat of some grass species may be highly permeable to toxic ions such as aluminum at low soil pH, thus making aluminum readily available for seed uptake in amounts that affect the seed embryo during imbibition (Maddox and others, 1977).

Since wheat is an annual grass species, its growth would be expected to be considerably greater than that of fescue during the first year. As such it would utilize most of the available light, nutrients, and moisture. Fescue would be expected to germinate and some survive the first year, but with less growth than if planted alone. In the second year increased fescue growth would be expected, as wheat would no longer be present to compete for available light, nutrients, and moisture. Erosion would be expected to be reduced by the presence of wheat stubble, which would intercept rainfall, and the wheat root mass, which would hold the soil particles together. Also, if additional fescue seeding is done by broadcasting, the stubble will help prevent the light fescue seeds being carried away by surface runoff. This is especially important on the steeper slopes and drainage ways.

The yields of wheat planted in 1975 in Fields 2 and 3 were similar, which showed again that to produce high yields of wheat on minesoil the pH must be at a level that will not adversely affect plant growth. In the case of Field 3 the natural soil pH was sufficiently high to promote plant growth, whereas in the case of Field 2 lime was added to raise the pH to a level adequate for plant growth.

The higher yield of wheat planted in 1975 in Field 3 compared to that in Field 4 showed the necessity for measuring the pH in each field before planting. Also, the yields showed that hard wheat, like soft wheat, will not yield high unless the pH is at a level that does not adversely affect plant growth.

The exceptionally high yield of wheat of about 40 bu/ac produced in Field 5 showed the efficacy of fertilizing and burying shale fragments deeper in the minesoil to minimize the oxidation of pyrite.

Overall the wheat yields of the 5 fields showed that wheat is well suited to minesoil, providing the pH is high enough and sufficient nitrogen, phosphorus, and potassium are available to insure the development of a good stand of wheat. Additionally, the comparisons showed the efficacy of burying acid-producing shale fragments deeper in the minesoil in producing good stands of wheat on minesoil. The wheat yield of Fields 1, 2, 3, and 5 (wheat planted November 1975) averaged 31 bu/ac, which compares well to the average yield of wheat of 28-40 bu/ac expected on Parsons soil in Crawford County, depending on the management techniques employed and how they are employed (U.S. Department of Agriculture, Soil Conservation Service, 1973).


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Kansas Geological Survey, Geology
Placed on web Oct. 25, 2018; originally published 1982.
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