TITLE:
Lithostratigraphic and Geochemical Characterization of Tobene Phosphate Deposits: A Case Study of Tobene South 1
AUTHORS:
Ndeye Khady Ndiaye, Mouhamadoul Bachir Diouf
KEYWORDS:
Tobene, Taiba, Keur Mor Fall, Ndomor, Sandy Recovery, Silico-feralitic
JOURNAL NAME:
International Journal of Geosciences,
Vol.14 No.2,
February
28,
2023
ABSTRACT: Tobene is the third exploitation panel of the Taiba
Phosphate deposits. It is divided into five sectors and its exploitation
started in 2003 after the closure of the Ndomor and Keur Mor Fall panels. The
Taiba phosphate deposit has been the object of several studies based on
lithology, biostratigraphy, geochemistry, and petrography; however, few
investigations on the variation in thickness of the phosphate layer within the
Tobène sector have been conducted. This study seeks to analyze the
lithostratigraphic and geochemical characteristics of the phosphate layer in
the Tobène South1. Results from the lithostratigraphic study show from top to
bottom the following succession: the sandy overburden, the sandstone formation,
the Silico-feralitic formation, the variegated roof clays, the Taiba formation
(homogeneous ore and heterogeneous ore), and the foliated attapulgite of the
wall. Geochemical analysis reveals an unequal distribution of major oxides (P2O5,
CaO, Fe2O3, Al2O3, and SiO2).
The area is dominated by P2O5 concentrations between 20%
and 32%, the K parameter (=CaO/P2O5) has an average of
1.36. The iron associated with aluminum (feral) is present in the southern part
and on the contours of the sector; the dominant silica concentration is 20%.
Correlations established between the major oxides show a strong relationship
with p-values 0.05, nevertheless there is proportionality in the
evolutions between the chemical variables CaO and P2O5,
on the other hand, an opposite evolution between P2O5 and
the two chemical parameters silica (SiO2) and feral.