E.O.  Odeyemi, O.O.  Ige, O.D.  Obasaju, O.O.  Ogunsanwo, 
    Geotechnical and Mineralogical Evaluations of Two Major Clay Deposits in
Southwestern Nigeria,
    Journal of Engineering and Applied Sciences,
    Volume 14,Issue 23,
    2019,
    Pages 8639-8646,
    ISSN 1816-949x,
    jeasci.2019.8639.8646,
    (https://makhillpublications.co/view-article.php?doi=jeasci.2019.8639.8646)
    Abstract: A total of 10 clayey samples derived from charnockite and granite from parts of Southwestern Nigeria
(Ilemosho, Ekiti State and Okelele, Kwara State) were subjected to geotechnical and mineralogical tests in order
to evaluate their suitability as raw materials for various engineering works. Classification tests carried out on
these soils include: grain size analysis and Atterberg limits determination while improved tests include
compaction, permeability and mineralogical test using XRD. The grain size analysis shows that Okelele soils
(OKL1-OKL5) gravel percentage range from 2-8%, percentage of sand range from 15-38%, silt percentage range
from 11-33%, clay percentage range from 43.7-50% while Ilemesho soils (ILM1-LM5) have gravel percentage
range from 1-6%, percentage sand from 9-63%, silt percentage range from 7-52% and clay percentage range from
14-45%. The plastic limit of the soils range between 18-34%, plasticity index (8-47%); shrinkage limit (5.9-10%);
activity (0.5-1.0); soil type (normal). The MDD and OMC of the soils when compacted at the energy of the
standard proctor gave 1.30-1.60 g/cm<sup>3</sup> and 12.0-23%, respectively. The coefficient of permeability is in the order
of 10<sup>-3</sup>-10<sup>-4</sup> cm/sec which are in the range of impermeable soils. The soils contain no undesirable mineral that
can constitute working problem in the field. The soils can be used as liners in landfill systems and to some
extent as fill in dam construction and subgrade materials.
    Keywords: Southwestern Nigeria;Atterberg limits;grain size analysis;coefficient of permeability;Okelele soils;subgrade materials