Manganese ore deposits in Egypt are found mainly in the Um Bogma district in Sinai and the Halaib 'Elba' region in the eastern desert, with varying geological settings and mineral compositions. The Um Bogma deposits are largely associated with Paleozoic sediments, while deposits in Halaib 'Elba' are primarily located in Miocene sedimentary rocks and are mined through limited operations. Both regions exhibit unique mineralogical characteristics and formation theories, ranging from epigenetic to primary sedimentary origins.

1. Lecture 8:
Hassan Z. Harraz
hharraz2006@yahoo.com
2016- 2017
@ Hassan Harraz 2017

2. Manganese ore deposits are widely scattered in
various districts in Egypt.
They occur at some localities in Sinai Peninsula and at
a few localities in the Eastern Desert.
Manganese deposits are known:
1) in the Um Bogma district in west central Sinai; and
2) in the Halaib "Elba" district in the southern portion
of Eastern Desert.
3) In addition, minor occurrences are known in Wadi
Mialik near Abu Ghosun and Ras Banas in the
Southern Eastern Desert, and Wadi Abu Shaar El Qibli
(Black Hill), to the north of Hurghada (Fig. ).
2

3. Table 1: Manganese ores information
Area Location Age Reserves
(M tons)
Produced
(1000 t/y)
Average
Content,
MnO2
Associated
constituents
Eastern
Desert
Wadi Abu Shaar El
Qibli
Wadi Mialik
G.Elba & Abou
Ramad
Na
Na
Na
Na
120
Na
35.8-
45.14
42.17
45.0
Fe2O3, SiO2,
clays
Sinai Abu Zunima Paleozoic
sediments of
Lower
Carboniferous
5 120 38 Fe2O3, SiO2,
clays
Total production in 2013 →35.6(1000 t/y)
3

4. Um Bogma District
 Um Bogma region west central Sinai are considered to be the most important area in Egypt for
manganese deposits.
 Extensive workable manganese deposits contributed significantly to the Egyptian economy up to
1967, when the mines were abandoned.
 Reopening the best mines is being considered and evolution of newly discovered occurrence.
 It is also producing ferromanganese alloys at the plant installed at nearby Abu Zeneima, a port on
the Gulf of Suez.
 Manganese ore deposits occur wide spread at eight localities of the manganese deposits from
the Um Bogma region, west central Sinai. These localities are:
1) Abu Hamata left,
2) Abu Hamata right,
3) Abu Thor,
4) Abu Zarab,
5) Rass EI-Homara ,
6) Area 10,
7) Area 9, and
8) Area 8.
 Manganese ore deposits occur in Paleozoic sediments of Lower Carboniferous age.
 The reserve of these ores in Um Bogma is about 1.7 million tonnes.
4

5. Type Lump
%
Mn 30 - 35
Fe 20 - 25
P <0.1
SiO2 12 - 15
Al2O3 2 - 7
K2O <0.5
Na2O <0.4
CaO 1-3
MgO 1-2
Particle Size Distribution
Lump
0 - 15 cm >90 %
>15 cm <10 %
Sinai Manganese Ore
5

6. 6

7. Figure: (a) The lower sandstone series capped with Um Bogma Formation (A Sarabit El-Khadim Formation, B Abu
Hamata Formation, and C Adedia Formation).
(b) Layer of manganese ore interbedded with dolomites of Um Bogma Formation.
( c ) Manganese lens in the dolomite of Um Bogma Formation.
(d) Green copper staining in the fine-grained sandstone of Sarabit El-Khadim Formation
7

8. Abu Thora Formation
Um Bogma Formation
Sarabit El Khadim-Adedia formations
Precambrian Basement
8

9. 9

10. Fig.2 : Distribution map of the Lower Carboniferous in the Um Bogma area, west-central Sinai,
Egypt (after Kora and Jux, 1986).
10

11. Egyptian Ore Deposits
11

12. Table 2. Chemical composition of Um Bogma manganese ores.
Low Mn Ore
wt%
Medium Mn Ore
wt%
High Mn Ore
wt%
Fe2O3 30.37 17.94 14.96
MnO2 35.30 43.00 48.59
Na2O 0.30 0.24 0.24
MgO 1.57 1.52 0.86
CaO 3.02 2.28 2.25
Al2O3 0.96 2.10 1.03
SiO2 3.08 5.08 2.42
P2O5 0.17 0.33 0.28
SO3 0.72 0.73 0.53
K2O 0.19 0.31 0.27
TiO2 0.38 0.15 0.07
Cr2O3 0.05 0.06 0.06
Co3O4 0.08 0.07 0.06
NiO 0.05 0.05 0.06
CuO 0.10 0.11 0.22
ZnO 0.64 0.39 0.47
PbO 0.05 0.06 0.04
BaO 1.55 2.29 1.62
SrO 0.09 0.14 0.09
Cl 0.19 0.14 0.11
L.O.I 11.70 11.80 12.40
Mn/Fe 1.46 3.32 4.54 12

13. Geologic setting
The oldest exposed sedimentary rocks at Um Bogma district belong to the Pre-
Carboniferous and Carboniferous ages.
These rocks unconformably overlie the Precambrian rocks.
Three stratigraphic rock units in the Um Bogma region starting from the base:
i) Lower sandstone unit (Carbo-Ordovician to Devonian)
ii) Middle carbonate unit (Um Bogma formation, Lower Carboniferous):
 This is represented by dolomite and limestone rocks and are covered
conformably the lower sandstone unit. Four members are differentiated from
base to top:
 Dolomite and manganese-bearing member,
 Silt-shale member,
 Marly dolomite and silt member, and
 Upper dolomite member.
iii) Upper sandstone unit (Visean) this is represented by medium to coarse grained
sandstone. Some beds are almost snow-white, friable sands with three kaolinitic clay
layers.
 Structural pattern of the west central Sinai shows that faulting is much more pronounced
than folding. Faults are the result of successive movements which affected the area in
different ages. Faulting has taken place periodically since the late Paleozoic, increased in
intensity and areal extension progressively and reached its climax in the Oligo-Miocene
period.
13

14. Ore deposits
 The manganese ore is a stratiform type
occupying more or less the same
stratigraphic horizon in the dolomitic
limestone member of the Um Bogma
formation which caps the clastic Adedia
formation.
 Ore deposits always tend to occupy a
particular stratigraphic horizon (i.e.
Dolomite and manganese-bearing
member), representing the base of the
middle carbonate (dolomitic limestone)
unit, which belong to Lower
Carboniferous.
 The manganese bodies are usually
surrounded by a zone of calcareous
shale, siltstone or sandstone that form
the transition with the surrounding
dolomite.
 The ore bodies usually show abrupt
contacts with the dolomite and are
frequently found to fill depressions in
the underlying Adedia formation.
Forms
 The individual ore bodies vary in
length and thickness, and are
often surrounded by a transition
zone of calcareous shale or
sandstone between the
surrounding dolomite.
 The ore bodies are irregular in
shape, tending to be lenses or
lenticular beds. The thickness
varies from 10 cm to 8 m and the
extent of the beds may reach
100 m.
 In some occurrences, the ore
bodies are present as veins
cutting the calcareous shale that
forms a transition with the
dolomite.
 Several forms characterize the
constituents of the ore deposits
such as massive crystalline,
granular, nodular, botryoidal,
reniform, fibrous, radiating,
need-like crystals, earthy soft
and ochreous varieties.
14

15. Mineralogy
 The ore body varies in composition from pure manganese ore to pure iron ore but it generally represents
a mixture of the two ore in variable concentrations.
 Small lenses are richer in Mn than the lenticular beds, where Mn occurs admixed with Fe.
 In the large ore bodies (i.e. layer ore lenses, i.e. those with diameter >50 m) is recognized.
Ore Minerals:
 The ore deposits are all in a highly oxidized state, the bulk of them being composed of pyrolusite,
psilomelane, hematite and goethite.
 In addition, polianite, manganite, cryptomelane, hausmannite, and ramsdellite are present in
subordinate amounts,
 while chalcophanite turquoise, malachite, alunite and pyrochroite occur as rare minerals.
 Gangue minerals include quartz, dolomite, calcite, barite, gypsum, and some clay minerals.
 Multistage formation of the Mn minerals is noticed especially in the regeneration and
recrystallization of pyrolusite.
 The transition between the ore bodies and the surrounding dolomite is abrupt distinguished by
enrichment (up to 73%) of quartz and grains.
 Um Bogma manganese ore deposits divided into three mineralogical zones:
i) The inner manqaniferous zone: essentially composed of psilomelane and pyrolusite with rare
manganite, hausmannite, polianite and pyrochroite. Hematite and clay minerals usually <25%.
The structure is massive, but concretions of pyrolusite may be present.
ii) The intermediate ferruginous-manganese zone: consists of psilomelane, pyrolusite and
hematite with up to 15% goethite, quartz, barite, and clay minerals. The ore is massive and
constitutes the main ore reserves of Um Bogma.
iii) The outer ferruginous zone: composed mainly of hematite and goethite with minor
psilomelane. Detrital quartz is common and spherulitic concentrations are frequent.
15

16. Mining techniques
Manganese is mined in the different localities by
underground methods, mainly room and pillar. In the
exposed outcrops it is mined by surface mining
techniques. The iron oxides are highly disseminated in
the manganese oxide matrix, which makes the
possibility of upgrading the ore is limited.
 The only processing steps carried out on the
manganese ores are crushing and screening. The
prepared ore is mixed with some imported high grade
manganese ore and fed to the smelter at Abu Zonaima,
Sinai to produce ferromanganese alloys [86]. The fines,
under size fractions, are piled in dump areas. It is
expected that agglomeration and magnetic roasting,
followed by low intensity magnetic separation may
improve the grade of the manganese ore in the
rejected fines, which in turn may increase the
manganese recovery.
16

17. Origin
The problem of the origin of the of the studied manganese deposits, which are carbonate-hosted, remains in dispute.
Two trends have been more or less defined:
a) Manganese ores are of epigenetic origin: Manganese ore is a result of the activity of ascending mineralized
hydrothermal solutions through the host rocks. The following arguments can be used as evidence of this:
i. The ore deposits are found in the immediate neighborhood of faults and are thicker and richer in manganese at
points close to the faults.
ii. Wherever ore occurs, the dolomitic limestones have partially or wholly disappeared. Where only a part of the
limestone series had disappeared in the vicinity of the ore deposits, it is always the lower part of the series which
has vanished with the upper beds being left.,
iii. The induced effect of weathering of the clastic rocks from Adedia formation capping the manganese-dolomite layer
(Um Bogma formation) is thought to have epigenetically added turquoise, malachite and alunite to the mineralogy
of manganese ore deposits.
iv. The presence of hausmannite, manganite, turquoise, malachite and alunite are indicative of hydrothermal deposits.
v. Criteria for replacement textures are reported with the manganese-iron ore deposit (e.g., relict, core and rim
replacement textures). Besides, the foraminiferal tests of Fusilina sp. are shown to be completely replaced by
polianite with their internal structures mostly obliterated.
b) Primary sedimentary-type of manganese ore: They gave the following considerations to support their theory:
i. The ore deposits always occupy the same stratigraphic horizon. These deposits are older than the predominant
faulting and folding in the district. In some cases, the deposits are cut and displaced by faults.
ii. There is no link between the ores and faults and where Mn deposits are present in fault, they are introduced as
fillings from above,
iii. The association of pyrolusite, manganite and psilomelane with goethite and hematite characterizes the
sedimentary deposits.
iv. The difference in the kind of insoluble residue between the inner and outer zones of the ore lenses indicates that
the major part of the ore was not formed at the expanse of the surrounding sandy dolomite, but rather associated
with a different lithology.,
v. There is no transition in mineralization between the ore bodies and the overlying unconformable strata, in contrast
with the narrow transition zone between the ore and the laterally surrounding dolomites.
vi. The dolomitization is contemporaneous with the mineralogical and chemical reconstitution of the zoned
deposits,
vii.The zoned pattern in the larger ore body indicates a low pH - high Eh conditions at the rims, and high pH- low Eh in
the cores. The mineralogy also indicates a low temperature of formation in a sedimentary environment (i.e., a
shallow marine origin of the Mn ore deposits).
17

18. Halaib "Elba" Region
Mode of occurrence:
The manganese ores occur in sedimentary rocks of Miocene age in more than
24 areas within the Shalateen -Halaib region, situated in the southern
extremity of the Egyptian Eastern Desert near the Red Sea coast.
The manganese ores occur in the form of veins that are mainly found in
sedimentary rocks probably of Miocene age
 All occurrences being located within a featureless coastal plain
consisting of sands and gravels with coral limestones and slightly raised
beaches along the Red Sea.
In a few cases (i.e., To the west of this plain), manganese deposits occur as
fracture fillings in granitic rocks.
The manganese ores occur :
 either in veins trending within a range of N28o-40°W in a belt of more
than~70 km long and less than 7 km wide,
 or occasionally replacing the Miocene conglomerates and limegrits.
The veins are steeply inclined and fill fault planes; their wails generally show
slickensided surfaces. They have a general trend ranging from 118o to 13o and
are all located within a belt of more than 70 km long and less than 7 km wide
(see fig. 1), which is almost parallel to the general trend of the veins. The faults
are all
18

19. G. Elba
19

20. 20

21. Halaib "Elba" Region
 Mineralogy:
The ore minerals include: pyrolusite, psilomelane, cryptomelane, ramsdellite,
todorokite, and nsutite, in addition to occasional goethite and hematite.
The gangue minerals include: quartz, barite, black calcite, opal, and
chalcedony.
Ore Types:
Three ore-types were distinguished by Basta and Saleeb (1971) as following:
i) Hard crystalline ore consisting mainly of pyrolusite (MnO2) or ramsdellite
(MnO2) or both,
ii) Banded colloform ore consisting mainly of psilomelane ((Ba,H2O)2Mn5O10),
and in places cryptomelane [KMn4+
6Mn2+
2O16 or K(Mn4+,Mn2+)8O16], and
iii) Soft nodular ore consisting of todorokite ((Na,Ca,K)2(Mn4+,Mn3+)6O12•3-
4.5(H2O)) with minor amounts of psilomelane (or cryptomelane), nsutite
((Mn4+,Mn2+)(O,OH)2), and pyrolusite.
Black calcite and barite occur in some of the veins and increase
with depth.
21

22. Halaib "Elba" Region
Mining
 More than 24 manganese occurrences have been mined
 Manganese mining is restricted to elementary operations due to the remoteness
and unfavorable conditions of the area.
 Mining is carried out by stripping the hanging wall, thus costing has limited exploitation
to a depth of 20 m or less.
 Mining of the Elba manganese ore started in 1955, and total of 40000 tons of high-
grade ore (average MnO2 about 74- 78 % and average MnO about 2 - 4.7 %) has been
produced.
Origin:
This manganese deposits formed by weathering of basement rocks rich in
manganese as a source of the ore which deposited in fissures and cracks with some
replacement along fracture walls (El Shazly,1957).
The ore is a very low-temperature epithermal fissure deposit of black calcite type
that occurs near the surface (oxidation zone) in brecciated zones along faults.
An epigenetic low temperature origin was proposed based on the predominance
of stable higher oxides of manganese and the absence of Mn-silicates, Mn-
carbonates, and Mn-sulphides which reflected near-surface deposition of the ore
(Basta and Saleeb, 1971).
22

23. Other manganese occurrences
Minor manganese occurrences are recorded
from:
a) Wadi Mialik near Abu Ghosun and Ras Banas
in the Southern Eastern Desert: The ore
occurs as fillings in fault zones and fissures
in amphibolites.
b) Wadi Abu Shaar El Qibli (Black Hill), in the
southern part of Esh El Mellaha range north
of Hurghada: a thin Mn deposit (~50 cm
thick) occurs in the Miocene sediments.
23

24. References
Attia, M. I. (1956). Manganese deposits of Egypt. The 20th
International Geological Congress, Mexico, pp. 143-171.
Basta, E. Z. and Saleeb, G. S. (1971). Elba Manganese Ore and
Their Origin, South Eastern Desert, Egypt. Mineralogical
Magazine, Vol. 38, pp. 235-244.
doi:10.1180/minmag.1971.038.294.13
El Shazly, E. M. (1957). Classification of Egyptian Mineral
Deposits. Egyptian Journal of Geology 1 ( No. 1) pp. 1-20.
Hussein, A.A.A., 1990. Mineral deposits. In: Said, R. (Ed.), The
geology of Egypt. 1990. A.A. Balkema,
Rotterdam/Brookfield, pp. 511-566.
Kora M, Jux U (1986) On the early carboniferous macrofauna
from the Um Bogma Formation, Sinai. Neur Jarbuch Geol
Palaontol H2:85–98
Mart, S. and Sass, E. (1972). Geology and Origin of
Manganese Ore of Um Bogma, Sinai. Economic Geology,
Vol. 67, pp. 145-155. doi:10.2113/gsecongeo.67.2.145
24

25. Egyptian Ore Deposits
Follow me on Social Media
http://facebook.com/hzharraz
http://www.slideshare.net/hzharraz
https://www.linkedin.com/in/hassan-harraz-3172b235
25