Um Bogma Research Articles

New weighting agent for water-based mud, um-bogma area, central Sinai, Egypt

A successful oil well drilling depends largely on a good mud Program. During drilling, mud provides sufficient hydrostatic pressure, removes drill cuttings and cools drill bits. Mud additives are always required to provide sufficient hydrostatic pressure to ensure borehole stability. Barium Sulphate (BaSO4) also known as barite is the prevalent weighting material but there is needed to develop local materials to augment the use of Barite. The present search is concerned on the early Carboniferous succession exposed in Um Bogma Formation, west central Sinai, Egypt as a new weighting agent in drilling fluids. The increases in the cost of drilling fluids and a shortage of using barite have introduced the locale dolomite as alternative weighting materials. The rheological properties of mud drilling samples weighted by local dolomite samples are being examined and investigated to know its potential to be used as a weighting material in drilling mud. Two mud samples were prepared which comprised of fresh water, caustic soda, bentonite and the weighting material. The weighting materials are added to achieve the required density. The first sample: Water-based mud with commercial barite of density between 10.00 lb/gm and 18.00 lb/gm. The second sample: Water-based mud with dolomite of density between 10.00 lb/gm and 18.00 lb/gm. These samples were analyzed and the density, rheological properties, aging of barite and dolomite and solid contents were investigated. At 10.00 lb/gm, the yield point of dolomite was 20.00 lb/100ft2 and barite 22.00 lb/100ft2 while the 10 second gel strength of dolomite was 30.00 lb/100ft2 and 22.00 lb/100ft2 for barite. Similarly, little difference was observed in plastic and apparent viscosities. At 10.00 lb/gm, the plastic and apparent viscosities of dolomite were 8.00 cp and 20.00 cp while barite was 8.00 cp and 24.00 cp. The result show that dolomite mud sample gave a little higher yield point and gel strength than barite mud sample. Therefore, dolomite has the potential to be used as weighting material in drilling mud in place of barite thereby enhancing the local content initiative of the government. When dolomite is sourced locally and used it will reduce overall mud and drilling costs.

Electrical, mineralogical, and geochemical properties of Um Gheig and Um Bogma Formations, Egypt

Dolostones of Um Bogma and Um Gheig Formations were studied using mineralogical and geochemical characterizations. The present work has tried to identify the origin, environment, pollution, and their electrical properties for the two formations. Also, the environmental geochemistry that resulted from the trace element concentration is examined here and we will try to differentiate between them. The study samples are fissile and highly fossiliferous dolomites. The two formations are classified as dolostones and nearly ordered. The mineralogy and geochemistry studies indicated that the two formations were formed under mixing zone at the near-surface oxidizing environment. The diagenetic features of both formations demonstrate many processes with clear effects. Dolostones of both formations may be precipitated from two different solutions. Meteoric water is the main supply, while the other solution may be resulted from the deep hydrothermal solutions that come up from deep faults. The distribution of Sr and Y content of dolostones at Um Bogma Formation indicated that they are precipitated at 110–150 °C, while those in Um Gheig are deposited at <150 °C. Electrical properties were measured at ~21 °C and humidity ~55% in a frequency range of 42 Hz–5 MHz. Slight changes were seen to be the result of changes in texture between grains and mineral composition for the two formations. The most effective factor in the changes of electrical properties is the distribution of grains (texture). The dielectric constant, generally, decreases with the decrease of discontinuous paths and frequency. Electrical conduction, usually, increases with the increase of conductor continuous paths and frequency.

Ground gamma-ray spectrometric studies of El-Sahu area, southwestern Sinai, Egypt

Based on the previous airborne gamma-ray spectrometric study carried out in southwestern Sinai area, El Sahu area was selected for detail ground gamma-ray spectrometric survey. This area is considered as a good target for radioactive mineral exploration. The study area is exposed in a Paleozoic basin covered by different rocks (ranging from Precambrian to Quaternary). The ground gamma-ray spectrometric survey has been conducted along the study area through random survey. The resultant gamma-ray spectrometric maps show different levels of radioactivity over the studied area, which reflect contrasting radioelement contents for the exposed various rock types. The studied area possesses total count ranging from 2.6 to 326 Ur, 0.1 to 2.8% K, 1.7 to 316ppm eU and 0.9 to 47.5ppm eTh. The highest uranium concentrations are located in the northern and southern parts of El Sahu area. They are mainly associated with Um Bogma Formation occurrences.Uranium ratio maps (eU/K and eU/eTh) as well as ternary maps show sharp increase of eU content over both potassium and thorium contents associated with the ENE and NNW trends in Um Bogma Formation, indicating an increase in the U-potentiality than the surrounding rocks. This indicates that the mineralization in the study area may be structurally-controlled.

Sequence stratigraphic controls on formation of dolomite: Insights from the Carboniferous Um Bogma Formation, Sinai-Egypt

In this paper we demonstrated that integrating sequence stratigraphy to dolomite formation is a probable approach for understanding the condition of dolomite formation at sediment surface or near subsurface.The employment of this technique is possible, because parameters controlling the sequence stratigraphic framework could have a profound impact on processes of dolomite cementation and dolomitization during early diagenesis.The Early Carboniferous dolostone beds in southwestern Sinai, Egypt, are interpreted to have been formed by dolomitization during transgressive system tract and early highstand system tract. The appropriate conditions for formation of extensive dolomite including, the seawater with modification by microbacteria or meteoric water dilution in the anoxic environment, exist of required ions (Ca2+, CO32-, Mg2+), nucleation sites and effective fluxes of dolomitizing fluid through the shelf were be provided during the Middle Viséan marine transgression in the Um Bogma area.By this mean, the dolomitization began early and penecontemporaneous with carbonate deposition at sediment surface or near subsurface and continued by precipitation of dolomite overgrowths and pore filling dolomite cements during later diagenesis, which is supported by oxygen isotope analyses.

Characterization and Exploitation of El-Gedida High-Mn Iron Ore, El-Bahariya Oasis, Western Desert, Egypt

Two strategies have been chosen for the exploitation of El-Gedida high-Mn iron ore containing 46.37 wt.% Fe and 7.53 wt.%Mn. The first one included magnetic roasting and subsequent low intensity magnetic separation. The second strategy involved a blend process of the El-Gedida high-Mn iron ore with the Um Bogma manganese ore. The magnetic separation failed to reduce the Mn content up to 4 wt.% and produced iron concentrate containing 52.15 wt.% Fe with a recovery of 94.47% and 6.45 wt.% Mn with a recovery of 71.95%. At this point, the magnetic separation is considered to be unsuitable process for upgrading the high-Mn iron ore. Moreover, this physical separation supported the microscopic prediction regarding the difficult liberation of iron minerals from manganese phase during the comminution process. On the other hand, blending the high-Mn iron ore with the Um Bogma manganese ore at weight ratio of 1/6 (El-Gedida sample/Um Bogma sample) produced a suitable mixture for making the ferromanganese alloys.

New heavy aggregate for offshore petroleum pipeline concrete coating Central West Sinai, Egypt

In this paper the local materials used in concrete mix are studied in a manner that they can resist the aggressive marine environment and mechanical damage, which can occur at several stages during transportation, construction and installation of the pipelines. In earlier studies we succeeded in finding the Egyptian ilmenite ore adequate for concrete weight coating and already utilized for many pipeline projects in Egypt. According to the presence of about 30% titanium oxides in ilmenite composition which may be extracted to be used in others strategically fields, the object of this paper is to study and evaluate the mechanical, chemical and physical properties of another local hematite high density iron ore to be used in subsea concrete weight coating for offshore petroleum pipelines. The results indicate that the local material of Um Bogma hematite iron ore can substitute both imported iron ore and local ilmenite from Abu Ghalaga in this field to reduce the cost effective and increased economical value of local ores. Laboratory and field tests were conducted for the hematite ore forming a concrete mix, composed of hematite ore, cement and fresh water according to international concrete coating specification requirements, the ore produces a concrete mix with 190–195pcf minimum dry density and compressive strength, after 28days of hydration, varying from 40 to 45N/mm2 (400–450kg/cm2) which comply with the international standards and specifications of submarine petroleum pipeline coating. In addition, local hematite shows superior results than local ilmenite and achieves 190pcf instead of 180pcf in case of using ilmenite.

Composition and origin of the dolostones of Um Bogma Formation, Lower Carboniferous, West Central Sinai, Egypt

Dolostones of Um Bogma Formation, Lower Carboniferous, have been possibly originated due to two different fluids. The main fluid source is related to meteoric water. The second fluid originated from deeper hydrothermal sources ascended through faults. The diagenetic features of Um Bogma Formation show many processes with conspicuous effects, including dolomitization, neomorphism, mechanical and chemical compaction, as well as it characteristics with stylolites, sutured and concave–convex contacts between grains. Based on mineralogical composition and petrography, the diagenetic environments are distinguished into shallow marine, near surface meteoric and burial environments. Dolostones in the studied area are possibly subjected to chemical and biochemical weathering. Um Bogma dolostones are nearly stoichiometric and ordered. Mineralogical and geochemical studies indicated that dolomite crystals were deposited in mixing zone of marine and meteoric water. In addition, it is formed in the near-surface oxidizing environment. The Sr distribution coefficient and Y content of the studied dolostones indicated that they are formed in temperature >110 and <150 °C. The CF (Contamination factor) and Igeo (Geo-accumulation index) have doubtlessly indicated that the Um Bogma dolomite rocks are polluted especially for Fe, Rb, Co, Cu, W, S, Ba, Zn, Zr and As. The studied dolomites of Area 45 and Um Bogma Mine sections are characterized by enrichment of Co and Cu, which indicated their deposition in marine environment. The studied dolomite of Um Bogma Mine is characterized by the enrichment of Zn, W, Ba, Mn, Ti and As which derived from hydrothermal solution. Consequently, the dolostones of the Um Bogma Formation are similar to those in Cayman Formation, Indies.

HYDROMETALLURGICAL PROCESSING OF EGYPTIAN BAUXITE

A bauxite ore from Um Bogma, Southwestern Sinai, Egypt was mineralogically characterized. It contains 70% gibbsite, 13.2% quartz and 11.0% kaolinite. Beneficiation of the ore reduced the quartz content to 2.4%. Hydrometallurgical processing of the beneficiated gibbsitic bauxite was performed by hot leaching with sodium carbonate and lime in an attritor. Aluminium was converted to soluble sodium aluminate low in SiO2 (<0.1%) and the recovery was over 95% for a short leaching duration of 30 minutes at 90 0 C. The residue was essentially composed of calcium silicate.

Hydrogen and oxygen isotopic compositions of sedimentary kaolin deposits, Egypt: Paleoclimatic implications

The clay fractions of sedimentary kaolin deposits representing different ages (Carboniferous and Cretaceous), types (pisolitic flint and plastic), and localities (Sinai and Aswan) from Egypt were analyzed for their H and O isotopic compositions to examine the paleoclimate conditions during their formation. The δD values of the Carboniferous deposits in Sinai range between −67‰ and −88‰, while the values for the Cretaceous deposits in Sinai range between −59‰ and −75‰. The δ18O values of the Carboniferous deposits range from 17.9‰ to 19.4‰ and the values for the Cretaceous deposits range between 19.2‰ and 20.4‰. The relatively low δD and δ18O values of the Carboniferous deposit at the Abu Natash area (−67‰ and 17.9‰, respectively) compared to other Carboniferous deposits (averages of −83.3‰, and 18.8‰ for δD and δ18O, respectively) could be due to isotopic exchange between this deposit and the adjacent dolomite and/or the enclosed hydrothermally-formed Mn ores of the Carboniferous Um Bogma Formation. The δD and δ18O values of the Cretaceous pisolitic flint kaolin deposit from Aswan (averages of −65‰ and 20.3‰, respectively) and plastic kaolin from the same area (averages of −66‰ and 19.5‰, respectively) are almost identical. The differences in the δ18O values between the clay fractions of the pisolitic flint kaolin (20.3‰) and the previously analyzed bulk kaolin of the same deposit (average of 17.5‰) suggest a significant effect of non-clay minerals on the isotopic compositions of the kaolin deposits.The H and O isotopic compositions plot close to the kaolinite line that marks the isotopic composition of kaolinite in equilibrium with meteoric water at 20°C. This indicates that the kaolinite from both the Carboniferous and Cretaceous deposits in Egypt formed by meteoric water weathering of the source rock(s). The δD and δ18O values also suggest that kaolinite of these deposits formed under warm-temperate to tropical conditions. The slight deviations of some samples from the kaolinite line suggest post-depositional modifications of the isotopic compositions of studied deposits probably due to the interaction between earlier-formed kaolinite and downward percolating meteoric water.The δD and δ18O values of the Cretaceous and Carboniferous deposits from all localities suggest that both deposits formed under similar climatic conditions due to the location of Egypt at almost the same distance from the equator either to the south during the Carboniferous or to the north during the Cretaceous.

Utilities of Landsat 7 data and selective image processing in characterization of radioactivity zones of Wadi Baba–Wadi Shalal Area, Westcentral Sinai, Egypt

Wadi Baba–Wadi Shalal area locates in the westcentral part of Sinai, Egypt. It is covered by a Precambrian basement rocks comprise the northern part of the Precambrian Arabo-Nubian crystalline massive. The lithologic and structural setting of the investigated area was interpreted from the digital Landsat-7 Enhanced Thematic Mapper Plus (ETM+) data. The structural lineament analyses for the lithologic units and their relationships to the high-radioactivity zones (HRZ) and the characterizations of HRZ of the study area are the main tasks of this article. Extraction algorithm was applied using Geomatica PCI package under the user defined parameters. The extracted structural lineaments have been evaluated and chicked using the visual interpretation and published works. The short-wave infrared spectral ETM+ band-7 was selected as an optimum data for automatic lineaments extraction since it scored the highest lineament frequency (1856) compared to the other visible and near infrared bands. The aeroradiometric color raster total count equivalent thorium (eTh) and equivalent uranium (eU) maps were used to delineate the highest radioactivity zones of the study area. A selective image processing technique (SIPT) is a new approach in Geomatica (9.1), which gives rise to valuable results in this work. The SIPT was carried out for the subset of the ETM+ data of the highest radioactivity zones. The spatial distribution of the structural lineament pattern maps for some low-radioactivity zones (LRZ) and for the highest radioactivity zones of the study area are prepared with their frequency rose diagrams. The NE–SW trend is the predominant structural lineaments trend in the investigated area. The NE–SW to the ENE–WSW directions are the predominant structural lineament trends in both the LRZ and the HRZ. These high-radioactivity zones of the investigated area are characterized by high lineaments density and lineaments-intersection density, restricted to Um Bogma Formation and younger granitic rocks and are not controlled by structural lineament trends.

Applied Geological Studies of Some Sinai, Egypt Ore Deposits to Utilized as Extender Pigments for Paint Manufacture

In this present study an investigation is carried out to search for the appropriate local substitutes for the imported paint pigments, samples collected from North, Central and South Sinai includes white sand, coal, quartz, kaolin, gypsum, limestone, chalk. The collected specimens were crushed and ground to powder varying in size between “5-50 um” for testing using laboratory mill. Several laboratory tests were accomplished to identify and evaluate the decorative and protective paint pigment including specific gravity, moisture content, pH value, oil absorption, x-Ray analysis, microscopic studies and others to prove that the selected local ores possess the required characteristics for pigments that can be utilized in producing the paint material in Egypt. The study indicates that the following local ores can be utilized as extender pigments to produce paint materials “calcium carbonate of south Sinai, white sand of Um Bogma, and gypsum of Ras Malaab. The estimated reserves of the studded ores give an indication of presence the sufficient quantities for stream production of the some paint pigments needed for Egyptian market. Key words: Field geology; Paint pigment; Extender pigment; Microscopic studies; X-ray analysis; Chemical analysis; Sinai; Egypt

Effect of alteration processes on the distribution of radionuclides in uraniferous sedimentary rocks and their environmental impact, southwestern Sinai, Egypt

The contents of natural radionuclides in various types of sedimentary rocks in Um Bogma Formation and base of El Hashash Formation were determined by gamma- ray spectrometry. Three types of lower Carboniferous sedimentary rocks were investigated; sandstone (El Has- hash Formation), dolostone and argillaceous sediments (Um Bogma Formation). The alteration processes are dolomitization, dedolomitization, karstification and lateri- tization. The specific radioactivity of 238 U, 226 Ra, 232 Th and 40 K determined in different samples, indicate that 238 U and its decay products contribute primarily to the high natural radioactivity of rocks. The maximum concentration of 238 U reached up to 2129.36 ppm in argillaceous sedi- ments. The average concentrations of determined radio- nuclides ( 238 U, 226 Ra, 232 Th and 40 K) are 8.34 ppm, 7.88 ppm, 4.68 ppm and 0.3%, respectively in sandstone. In dolostones the average concentrations are 418.69 ppm, 808.75 ppm, 3.14 ppm and 0.29%, respectively. For argillaceous sediments are 276.88 ppm, 419.49 ppm, 11.47 ppm and 0.93%, respectively. The 238 U/ 226 Ra ratio in sandstone ranges between 0.89 and 1.25, while in do- lostones and argillaceous sediments are 0.27-2.63 and 0.27-1.83, respectively. These variations in the concen- trations of radioelements and their ratios are due to the action of the alteration processes affected these different sedimentary rocks in different times. Environmentally, the Raeq in dolostones and argillaceous sediments exceeds the permitted limits, while in the sandstone samples; it is within the permissible levels.

Petrogenesis and age dating of continental Mesozoic basalts, Um Bogma area, Sinai, Egypt

Petrogenesis and age dating of continental Mesozoic basalts, Um Bogma area, Sinai, Egypt

Assessment of hazardous mine waste transport in west central Sinai, using remote sensing and GIS approaches: a case study of Um Bogma area, Egypt

Um Bogma area is the most famous mineralized locality in Sinai, Egypt. It is characterized by the presence of manganese, iron, and copper deposits. Apart from the mill tailings and spoil heaps, the results indicated the decrease of soil contamination downstream. As a result of random manganese mining activity in Um Bogma area, many hazardous elements such as iron, copper, manganese, lead, and zinc as well as many others associating heavy metals such as arsenic, selenium, and sulfur are dispersed in the environment. This study assesses and monitors the environmental impacts of such mining activities in the west central Sinai, using multitemporal spectral remote-sensing sensors (MSS 1972, TM 1986, and ETM+7 2000). The results have shown the very high potential of temporal imagery in mining-related contamination either directly through mineral and rock mapping of the mining waste and residues and related contaminated areas.

Radiogenic Isotope Fractionation as an Indication for Uranium Mobility in the Granites of El Shallal Area, West Central Sinai, Egypt

The granitic rocks at Wadi El Shallal area are categorized into metaluminous hornblende-biotite granites and peraluminous two- mica granites. The chemical analyses indicate that the two-mica granites are slightly altered and characterized by high uranium and thorium contents (averages 20.27 and 27.12 ppm, respectively). Compared to the hornblende-biotite granites, the 230 Th/ 234 U and 234 U/ 238 U activity ratios of the two-mica granites display values that depart significantly from equilibrium. The sample plots of the two granitic types are distributed in a trend reflecting more 234 U loss from the two-mica granites. Leaching experiments confirmed that the area around mineral grain boundaries are more enriched in 234 U relative to its parent 238 U as a result of α-recoil process that displaces the daughter nuclei outside the grain surface. This daughter ( 234 U) is ejected from the grain into the open spaces and therefore, subjected to leaching by fluids. The observed uranium series disequilibrium in the granitic rocks from El Shallal area reflects isotopic fractionation and a recent migration of uranium in the two-mica granites. The high uranium contents and U-Th isotopic composition of the two-mica granites fairly suggest that these rocks are probably the source for uranyl mineralization of the nearby Um Bogma Formation reflecting a history of leaching, mobilization and precipitation by meteoric and groundwater. However, more intensive investigations for uranium *Dept. Geology, Fac. Science, Ain Shams Univ., Cairo, Egypt.

First record of Heterocorallia (Hexaphyllia Stuckenberg 1904) from the Lower Carboniferous (Viséan) of west-central Sinai, Egypt

The first record of Heterocorallia anywhere in Egypt is in Early Carboniferous (Visean) shallow-marine carbonates of the Um Bogma Formation in west-central Sinai. These strata contain the small, single heterocoral speciesHexaphyllia marginata (Fleming), for which we statistically document marked, intraspecific morphological variations.Hexaphyllia marginata has a global geographical distribution longitudinally but occurs only in the tropical and sub-tropical regions within a latitude range of about 30°N to 30°S. This first EgyptianHexaphyllia occurs with a particular association of exclusively non-dissepimented, small, solitary rugose corals, brachiopods, bryozoans, and other organisms. Small-sizeHexaphyllia marginata might have been so resistant palaeoecologically that they survived even in the unfavourable habitat conditions on an open, subtropical platform.

Multiple dolomitization events of the Lower Carboniferous Um Bogma Formation, west central Sinai, Egypt

The Lower Carboniferous Um Bogma Formation in west-central Sinai, Egypt displays extensive and pervasive dolomitization. The combined petrographic/isotopic/stratigraphic investigations of the dolomite succession in the studied area reveal the presence of two distinct dolomite types: dolomite type (I) is confined to the basal part of the succession being associated with economic ferro-manganese deposits, and dolomite type (II) is located near the upper part of the succession. Silt, clay and marl beds vertically separate the two dolomitic units.

Simultaneous extraction of manganese from low grade manganese dioxide ore and beneficiation of sulphur slag

Abstract Pure manganese dioxide was successfully produced from low grade pyrolusite ore (β-MnO 2 ) and sulphur slag. First, the reduction of β-MnO 2 , introduced as pure pyrolusite was studied using different ratios of elemental sulphur at different temperature (300–400 °C), in air or in closed stainless tube. The reduction process was followed by leaching of Mn with H 2 O, 0.1, 0.5 or 1 M H 2 SO 4 . β-MnO 2 was found to undergo a reduction process at obviously low temperature giving Mn 3 O 4 , MnS and MnSO 4 depending on the applied conditions. The efficiency of Mn leaching ranged from 40 to 99%. The optimum conditions of reduction and leaching were applied to low grade pyrolusite from Um Bogma, Sinai and sulphur slag remained from the sulphuric acid industry. MnSO 4 was prepared by concentrating the liquor extract. γ-MnO 2 was produced either by precipitation from the liquor extract using ammonium peroxodisulphate or by electrodeposition on platinum anode. The products were characterised by X-ray diffraction, thermal and chemical analysis.

Sedimentary Origin of the Mn-Fe Ore of Um Bogma, SouthwestSinai: Geochemical and Paleomagnetic Evidence

Paleomagnetic, mineralogical, and geochemical investigations have been carried out to estimate the origin and age of the Mn-Fe ore of Um Bogma Formation of the early Carboniferous. For this purpose, oriented samples were collected from 26 sites in the Mn-Fe ore and host rocks of Um Bogma Formation and the overlying sandstone of Abu Thora Formation. The paleomagnetic pole, determined from the characteristic remanent magnetization of the Mn-Fe ore from 20 sites and the hosting rocks of Um Bogma Formation, is located at 22° S, 97° E (Dp = 3.9°, Dm = 7.4°). This paleomagnetic pole position falls close to the Carboniferous poles of Africa, suggesting that the Mn-Fe ore and associated rocks of Um Bogma Formation were deposited during the Carboniferous. Furthermore, the paleolatitude determined for these rocks, based on the mean paleomagnetic inclination, suggests that the Mn-Fe ore of Um Bogma was deposited at a latitude 10° south of the equator, i.e., in tropical conditions. Mineralogical and geochemical investigations support the paleomagnetic results. The ore is enriched with Na, K, Ca, Mg, Sr, Co, and Ni, suggesting that the Mn-Fe ore of Um Bogma is of sedimentary marine origin. The enrichment of some ore samples with hydrothermal elements (As, Zn, Cu, Pb, V, W, and F) is restricted to faulted areas, indicating that a younger phase of hydrothermal activity affected the ore after its deposition. Samples from the overlying Abu Thora sandstone yield a mean paleomagnetic direction of D = 326°, I = 42°, k = 19.3; α 95 = 17.9°, which provides a paleomagnetic pole position at latitude 59°, longitude 302° (Dp = 13.5°, Dm = 22°). This magnetization is significantly different from that of the Mn-Fe ore and host rocks and is assigned a Cretaceous age. The porous sandstone acquired its magnetization long after deposition, most likely by diagenetic chemical processes associated with red pigmentation.

Sedimentary Origin of the Mn-Fe Ore of Um Bogma, Southwest Sinai: Geochemical and Paleomagnetic Evidence

Sedimentary Origin of the Mn-Fe Ore of Um Bogma, Southwest Sinai: Geochemical and Paleomagnetic Evidence