Journal of Geoscience, Engineering, Environment, and Technology
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Mineralogy and Geochemistry of Gold Ore Low Sulfidation -Epithermal at Lamuntet, Brang Rea, West Sumbawa District, West Nusa Tenggara Province
Get PDFThere are two Artisanal Small scale Gold Mining (ASGM) location in Lamuntet, Brang Rea Subdistrict, West Nusa Tenggara Regency, namely Nglampar and Song location. Nglampar and Song location are included in the low sulfidation epithermal gold deposit system. The research purposes to analyze mineralogy and geochemistry of gold vein deposits and determine system of low sulfidation gold ore in Nglampar, Lamuntet Village. The methods used to determine the mineralogy of gold vein deposits are petrography, mineragraphy and X-ray diffractometer (XRD) analysis, while geochemical analysis using Scanning Electron Microscope (SEM) with Energy Dispersive X-Ray Spectroscopy (EDS), Fire Assay (FA) and Atomic Absorption Spectrophotometry (AAS). The results showed that the minerals contained were quartz (Qz), sericite (Ser), Chalcedon (Chc), chlorite (Chl), pyrite (Py), sphalerite (Sph), galena (Gn) , gold (Au), chalcopyrite (Cp), argentite (Ag), arsenopyrite (Apy), Azurit (Az), Malakit (Mal) and bornite (Bn). Abundant mineral availability such as sphalerite, galena, chalcopyrite and arsenopyrite are characterized by high levels of Zn, Pb, Cu and As the metal in vein deposits. This can be seen on the chemical content of ore in gold vein deposits ie Au 0.1 ppm -27.8 ppm, Ag 3 ppm-185 ppm, Pb 101 ppm - 35,800 ppm, Zn 73 ppm-60,200 ppm, Cu 26 ppm - 1,740 ppm, and As 150 ppm - 6,530 ppm. Based on the results of SEM-EDS analysis shows that the type of gold mineral is the electrum because of the content of Ag> 20%. Based on those characteristics of the mineralogy and geochemistry in this study showed that low sulfidation gold ore in this area is categorized as polymetallic gold-silver system. 
The Key Parameter Effect Analysis Of Polymer Flooding On Oil Recovery Using Reservoir Simulation
Get PDFAs time goes by, there will be decreasing of production rates of a field along with decreasing pressure. This led to the necessity for further efforts to increase oil production. Therefore, pressure support is required to improve the recovery factor. Supportable pressure that can be used can be either water flooding and polymer flooding. This study aims to compare recovery factor to scenarios carried out, such as polymer flooding with different concentrations modeled in the same reservoir model to see the most favorable scenario. The method used in this research is reservoir simulation method with Computer Modeling Group (CMG) STARS simulator. The study was carried out by observing at the pressure, injection rate, and polymer concentration on increasing field recovery factor. This study used cartesian grid with the assumption of homogeneous reservoir, there are no faults or other geological condition in the reservoir, and driving mechanism is only solution gas drive. This reservoir, oil type is light oil with API gravity 40.3˚API and layer of conglomerate rock. The simulation result performed with various scenarios provides a good result. Where the conditions case base case field recovery factor of 6.7%, and after water flooding produced 25.5% of oil, whereas with tertiary recovery method is polymer flooding was carried out with four concentrations of 640 ppm, 1,500 ppm, 3,000 ppm, and 4,000 ppm obtained optimum values at 4,000 ppm polymer concentration with recovery factor 28.9%, SOR reduction final value 0,5255, polymer adsorption of 818,700 ppm, reservoir final pressure 1,707 psi, and an increase in water viscosity to 0.94 cP
Saltwater Intrusion Zone Mapping on Shallow Groundwater Aquifer in Selat Baru, Bengkalis Island, Indonesia
Get PDFSaltwater intrusion becomes a common problem in coastal area. Northern coast of Bengkalis Island in Riau, Indonesia that contiguously to Malacca Strait is experiencing the problem particularly in Selat Baru area which considered as developing area and most of the people live close to the sea. Dug well is the main source of groundwater that had been used by the population in Selat Baru and as the increasing of land occupation, the demand of clean water is rising up followed by the number of dug well. A study of groundwater monitoring was conducted to identify the zone of saltwater intrusion. Field observation had done by measuring the water level and physical parameters of groundwater such as taste, pH, electrical conductivity (EC) and total dissolved solid (TDS) from 110 existing dug wells. Some conus feature had found from groundwater elevation map which indicated lower water level caused by excessive groundwater pumping. Generally, pH shows values from 6-8 that was still in range of water quality standard, but there are 20 wells (18%) that have pH below the water quality standard (slightly acidic water). Similar pattern had been observed from Electrical Conductivity (EC) and Total Dissolved Solid (TDS) map, higher value of EC and TDS was dominant in the northern part of study area and lower value in the south. Groundwater taste map also revealed the identical condition with EC and TDS map which dominated by brackish and saline water in the northern part. Therefore, the study area had been divided into two zones of groundwater saline water zone possibly caused by the saltwater intrusion in the northern part and freshwater zone from the center to the southern part
Soil Minerals Serving as Source of Arsenic in Alluvial Aquifers of Holocene: A Case Study from Indus Delta, Sindh, Pakistan
Get PDFGroundwater arsenic contamination is recently reported in the alluvial aquifers of Indus deltaic plain. Since the source of arsenic is believed to be natural as widely reported in other deltaic aquifers of same age (Holocene), it is imperative to evaluate the soil characteristics for identifying the sources of arsenic and its mobilization mechanism. For this purpose, 49 soil samples were collected from near aquifer sites in all three talukas of Tando Muhammad Khan district. Visual analysis revealed that soil is light grey in color with fine texture ranging from silt to silty-clay. The X-ray diffraction study reveals the occurrence of quartz, mica and clay minerals in all collected soil samples. Plagioclase feldspar is second dominant mineral group in the order of albite (calcian) >albite>albite (disordered) = anorthite > anorthite (sodian) = anorthite (disordered). Calcite is major carbonate mineral which is detected in 40 out of total 49 soil samples. The occurrence of other occasional minerals includes amesite, nitro-calcite, rutile and zinnwaldite. The frequency of micaceous minerals in collected samples is in the order of clinochlore> polylithionite> Biotite > phlogopite> muscovite. Polylithionite is found in about half of the total soil samples, where most of the aquifers contain arsenic >20 μg/L (Khan, 2014). Phlogopite is observed in seven soil samples which are also associated with clinochlore. On the other hand, biotite is found in 14 sediment samples collected from Tando Muhammad Khan and Bhulri Shah Karim talukas and muscovite occurs in three soil samples of Tando Muhammad Khan taluka. It can be concluded from present study that fine-grained Phyllosilicates have strong affinity for arsenic retention. These sediments are important source of arsenic Indus delta and other deltaic plains of the world
Geochemistry and tectonic setting of the supracrustal rocks from the central part of the Bundelkhand craton, India
Get PDFSupracrustal rocks (mafics and ultramafics) occurs along with banded iron formation, and felsic volcanics around Babina, Dhaura, and Mauranipur linear east-west trends in central part of the Bundelkhand craton represent Archean crust. The mafic and ultramafic rocks geochemically classified into Komatiite and Basaltic Komatiite and have high-Fe Tholeiitic in composition which may relate with the primitive mantle. The major and trace element geochemistry of mafic and ultramafic rocks correspond to hydrated mantle with wedge tectonic sources and ocean ridge geological characteristics
Analysis of the Sub-Surface Distribution of Graphite Minerals Using the Geoelectrical Resistivity Method in the Sabilambo Village, Kolaka Regency, Southeast Sulawesi Province
Get PDFSoutheast Sulawesi Province is one of the regions in Indonesia that has abundant mineral resources, the availability of several types of minerals is strongly influenced by the diversity of rock formations that make up the area. The metamorphic complex is one of the rock formations in the Southeast Sulawesi Province. Where the rock complex is divided into 2 (two), namely: Pompangeo Complex and Mekongga Complex, the distribution area of this metamorphic rock is estimated around 50% of the total land area of Southeast Sulawesi Province. This rock complex is very possible to contain mineral deposits, one of which is graphite mineral deposits. However, the problem that is now is the identification of the potential for subsurface distribution of graphite excavated material has not been carried out. Therefore, this research was conducted to determine the potential for subsurface distribution of graphite mineral deposits is using geoelectrical resistivity method where is using Wenner-Schlumberger configuration, this research activity was conducted in the Sabilambo Village in Kolaka Regency, where most of the research area is metamorphic complex. Based on the result of the resistivity analysis, subsurface distribution of graphite mineral deposits in the study area can be found on the surface to a depth of 33.5 meters below ground level, with layer thickness between 1.25 to 27.77 meters and has a resistivity value of 14.9 Ωm – 86.1 Ωm
Age and Paleobathymetry of Salodik Group in PohPagimana section, East Arm of Sulawesi Based on Foraminiferal Assemblages
Get PDFPlanktonic and benthic foraminiferal assemblages were used for age and paleobathymetry analysis of outcropping carbonate succession of the Salodik Group in Poh–Pagimana section, East Arm of Sulawesi. Twenty spot samples of carbonate rocks were collected from cut slope along the road between Poh and Pagimana. Age analysis conducted for each sample by its planktonic foraminifera assemblages and group into their age interval. The age range from Early Eocene to Pliocene. Benthic foraminiferal assemblages indicate paleobathymetry ranging from middle shelf to upper bathyal settings. Age analysis of the studied section show an older sediments (Early–Middle Eocene) overlie younger sediment (Early Miocene). This is interpreted as the evidence of thrust fault in the Poh–Pagimana section as part of thrust sheets of Batui thrust complex which imbricated on deformation zone. The youngest sediment which have suffered deformations shown by disordered age sequence is Pliocene in age (N20-21). The Eocene to Pliocene carbonate succession in the studied section was deposited relatively in the more basinward position compared to the carbonate-dominated sediments in the Tomori area which was deposited in the more landward position
