TITLE:
Geotechnical and Geochemical Assessment of Natural Sands in Ahanta West Area, Southwestern Ghana
AUTHORS:
Asante-Annor Asare, Kwabena Amponsah Ernest
KEYWORDS:
Geotechnical Assessment, Geochemical Tests, Natural Sand, Construction, Ahanta West
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.9 No.12,
December
31,
2021
ABSTRACT: Geotechnical and geochemical assessment of natural
sands being used as fine aggregates for construction purposes in Ahanta West
and its Environs was carried out, as well as addressing the environmental
problems associated with the exploitation of these sand through the sand
winning activities. The results from geotechnical and geochemical tests were
bench marked with British, American and Ottawa Standards for testing materials.
Representative samples were taken from five different sand winning sites
namely, Pompuni, Agona Banso, Fretsi, Tumentu stream and Fretsi river. The
geotechnical tests carried out were specific gravity, grain size analysis,
moisture content, silt content, permeability test using the constant head
permeameter method. The photometer (Hydro Test HT 1000) was used to determine
silica, sulphate and chloride concentrations in the sand samples. The oxides
for the geochemical analysis were determined using the X-ray fluorescence (XRF)
method. The results from the study areas showed that except for Fretsi, the specific
gravity, grain size analysis, moisture content, silt content and permeability
tests were within the acceptable range for natural sands. Sand samples from
Pumponi and Agona Banso had the required Cu and Cc values of being well graded.
Sulphate and chloride concentrations were within standards for all the samples;
however, silica was low for all the samples. Fe2O3, Al2O3,
MnO and Na2O did not meet the Ottawa sand standard. Natural sand is
not recommended to be used for construction purposes however, these sands may be treated or blended if
it is to be used for construction purposes. There are serious environmental
implications for the sand-winning activities in the study areas such as
stripped overburden, creation of pits and ponds, increased total suspended
solids in surface waters, and destruction of aquatic habitats which needs to be
addressed.