PROPOSED CHANGES TO SOIL TAXONOMY THAT MAY AFFECT MINE SOIL CLASSIFICATION

摘要

Mine soils begin developing horizons from natural processes after mining excavation and transportation of spoil ceases. Spoil deposits and altered landforms are easily recognized from a distance but the soils in those landforms seldom contain proof of their origin. Soil Taxonomy provides a few diagnostic horizons and materials and classes for mine soils. Most excavated or transported mine soils are identified in one of two suborders (Arents or Orthents) because they have no currently accepted diagnostic features other than remnant fragments of soil material. Mine soils (excavated and dredged) with sulfuric horizons are classified in "Sulf" Great Groups, although dredged deposits without sulfidic materials may classify in the Fluvents or Psamments suborders. There are no provisions in Soil Taxonomy to identify human transported material (HTM), human-manufactured or -modified materials, or to identify mine soils that contain those materials separately from natural soils such as in landslides. New designations and diagnostic layers and horizons are needed to establish new classes in Soil Taxonomy for HTM such as mine soils. The International Committee for Anthropogenic Soils (ICOMANTH) circulated letters requesting input for changes to describe, map, and manage mine soils. Most respondents would like to identify human-transported material with a special horizon prefix where evidence of mechanical transportation is left behind. Spoils left on the surface after surface mining or dredging presently have little variation in classification above the soil series level. Approximately two dozen soil series are available for identifying mine soils, although some of the series have overlapping properties. Many mine soils deposited following passage of the Surface Mining Control and Reclamation Act of 1977 contain densic materials due to compaction during reclamation, although none of the existing series recognize the densic contact that is the dominant factor in interpreting their use and management. Proposals to revise Soil Taxonomy will be submitted following recommendations from ICOMANTH with the goal of providing classes for mine soils with unique properties.