Environmental Assessment
Volume B-3.3
Mine
Soils
Ambatovy Project
31
January 2006
3.3.2.2 Mine Site Soils
Four major soil types were mapped from the field program and are summarized
below.
Armoured ferricrete soils were observed on topographic plateaus with a hard,
rock-like surface layer. These soils are classified as Entisols (Lithic
Haplumbrepts and Lithic Ustorthents) and Oxisols (Typic Acrohumox) under the
United States Department of Agriculture (USDA) system.
Pisolite soils were generally located on lower topographic positions than
ferricrete soils. Pisolites can contain a range of concretions and broken cuirasses
depending on slope position and other soil-forming factors. An enriched clay
layer can often be found under the concreted horizon and these soils were
generally classified as Oxisols (Haplorthox and Acrorthox) under the USDA
system.
Red/yellow ferrilitic soils were usually located in topographic lower slope
positions. These soils have fewer concretions and were classified as Ultisols
(Typic Paleudults) or as Oxisols (Oxic Dystropepts) under the USDA system.
Organic soils were located in depressions. They are developed on organic parent
materials, are acidic and have low base saturation. These soils are classified as
Histosols (Organic Hydromorphs) under the USDA system.
Additional details concerning baseline conditions are provided in Volume I,
Appendix 3.1.
3.3.3
Impact Assesssment
3.3.3.1 Issue Scoping
The main potential issues relating to soils are:
•
soil removal and disturbance;
•
soil erosion
•
loss of soil nutrients;
•
soil compaction;
•
soil contamination;
•
loss of unique soils; and
