Figure 19.— Aerial photograph showing mining and reclamation sequence at Energy 1 mine in Colorado. Contour furrows 

 (erosion control trenches and berms) parallel to topographic contours are cut in freshly graded and reshaped spoil (center) 

 next to new spoil (right side) and in second-season grasses (left). Mining, marl<ed by spoil piles, is proceeding in the left and 

 upper areas. Some small impoundments are produced in the smoothing operation (center and upper right). November 1978. 



right conditions of slope, climate, and composi- 

 tion (Schumacher and others, 1977, p. 19). 



Interpretations of what comprises a topsoil 

 suitable for reclamation have varied w^idely in the 

 past because the term does not have a clear 

 scientific definition even in soil science use. 

 Generally topsoil is considered an "enriching 

 layer" for plant development. In coal-mining 

 usage, topsoil has included (1) suitable over- 

 burden alone, usually that material whose chem- 

 ical or physical properties are more favorable 

 than the existing soils; (2) mixes of overburden 

 (fig. 28) and original soil materials, at times 

 required when original soil is thin, rocky, or 

 otherwise poorly constituted (fig. 29); (3) only 

 original soil materials, consisting of a mixture of 

 the upper layers, the final thickness of which 

 depends upon soil testing and the skill of the 

 scraper operator; and (4) the uppermost distinct 

 soil development layer generally referred to as 

 the "A" horizon. Office of Surface Mining regula- 



tions generally require that the top 6 inches of 

 the old surface be stockpiled and added to the 

 top of the new surface (U.S. Office of Surface 

 Mining, 1979, p. 15397); these regulations, how- 

 ever, permit mixtures of soil and overburden or 

 substitutions of overburden under certain 

 conditions. 



BIOLOGICAL FACTORS 



Biological factors affecting revegetation exist 

 both above and below the surface. The impor- 

 tance of subsurface biological components 

 such as bacteria, fungi, and arthropods, was 

 briefly discussed in the preceding sections. 

 These components are believed to be necessary 

 in establishing a self-sustaining vegetative com- 

 munity where large areas are disturbed by min- 

 ing operations (Cundell, 1977, p. 299). The Forest 

 Service (Lindsey and others, 1977; Williams and 



34 



