Figure 17.— Grooved, spray-mulched, and seeded slope at Seminoe 2 mine In Wyoming. This type of treatment is quite suc- 

 cessful and conforms to the natural landscape. The grooving, done with a chisel p\o\N, will become less evident with time. 

 Grooving helps to conserve moisture, reduce wind erosion, and prevent widespread rilling caused by sheetwash. October 

 1978. 



growth-inhibiting substances in overburden can 

 be diluted by mixing materials in the excavation 

 process. Where these substances have been 

 identified in advance by test drilling, the af- 

 fected overburden can be deliberately diluted by 

 slightly modifying dragline practices. More ex- 

 tensive toxic layers can be immobilized by 

 various burial methods (Dollhopf, 1979). Most 

 potentially toxic metals are only marginally solu- 

 ble under the highly alkaline conditions in west- 

 ern overburden and soil; therefore, they are not 

 readily available for plant use. In the absence of 

 significant copper under alkaline conditions, 

 however, molybdenum can be taken up in exces- 

 sive amounts by legumes. Boron can also form 

 toxic compounds in plants grown on sodium- 

 rich spoils. 



SOILS 



The replaced growing medium for revegeta- 

 tion is important in all stages of reclamation and 

 is probably one of the most significant factors in 

 long-term successful reclamation. The original 

 soils are a product of the long-term interaction 

 of the climate, parent material, landform, vege- 

 tation, and animal life that developed on and in 

 them. Soils form a critical part of the ecological 

 system; they contain a living system of their 

 own. Their chemistry, texture, and thickness is 

 adjusted to the land surface slope, and to eleva- 

 tion, temperature, and exposure. In theory, the 

 replacement of the original soils with a recon- 

 structed soil of similar characteristics would be 

 a requirement for long-term successful restora- 



32 



