scholarly journals On the digitalization of the parameters of native gold particles in the study of placers and concentrate and mineralogical studies

2021 ◽  
pp. 60-72
Author(s):  
BARANNIKOV Aleksandr Grigor’evich ◽  
Keyword(s):  
Grain Size ◽  
Native Gold ◽  
Digital Data ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Important Indicator ◽  
Gold Particles ◽  
Rigorous Approach ◽  
Average Grain Size ◽  
Average Size

Relevance of the work is due to the need to increase the efficiency of studying the particles of native gold in placers using morphometric (morphogranulometric) parameters in their documentation. Graphic materials (maps, plans, sections) based on digitalization of the collected data help to increase the reliability of the forecast, make it possible to use the selected areolas in combination with other methods when assessing ore-bearing zones and areas. Purpose of the work: development of a systematics of native gold identification on a morphometric basis. Substantiation on the basis of digital data of placer samples indicators – form of gold grains, average grain size, hydraulic particle size; study of the spatial variability of the revealed parameters of the metal within the rebuilt placers. Research methodology: diagnostics (description) of the morphology of gold grains and other typomorphic features based on the quantitative parameters of particles with the subsequent calculation of the shape coefficients (flatness, elongation); generalization and interpretation of the results of the description of native gold previously obtained during the exploration of the Ural placers. Results. The proposed systematics of native gold outwards on a morphometric basis allows a more rigorous approach to the identification of metal particles (excluding the subjectivity of describing the outward look of ore). When substantiating the average size of gold grains, significant discrepancies were noted in the results obtained by two independent methods: when measuring the parameters of gold grains on a morphogranulometric basis and using traditional sieve grain size analysis. The geological factors that determine the level of discrepancy between the compared methods are considered. It is about how the revealed discrepancies should be taken into account in the practice of forecasting and prospecting works. It is argued that the most important indicator characterizing the migratory mobility of gold particles in an aquatic environment is their hydraulic size (HS, cm/s). An approach to substantiating HS based on measurements of morphogranulometric parameters of particles (axes A, B, C) is proposed. Examples are considered based on the interpretation of the accumulated digital data in the mineralogical mapping of a number of ore-bearing areas and sites. Conclusions. Long years of studying native gold from placers using the developed systematics of particles on a digital (morphogranulometric) basis have been tested by the practice of forecasting and prospecting and research works. The described approach, based on digitalization of the accumulated information, is recommended for implementation and further improvement

scholarly journals A Conversion for Average Grain Size Based on Gamma Ray Well Log: Application in the Second Member of Xujiahe Formation of Anyue Area, Sichuan Basin

2021 ◽  
Vol 9 ◽  
Author(s):  
Liang Chen ◽  
Hancheng Ji ◽  
Nansheng Qiu ◽  
Liang Zhang
Keyword(s):  
Grain Size ◽  
Sichuan Basin ◽  
Gamma Ray ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Sediment Grain Size ◽  
Xujiahe Formation ◽  
Average Grain Size ◽  
Logarithmic Relationship ◽  
Clastic Reservoirs

The grain sizes of clastic rock sediments serve as important depositional indicators that are significant in sedimentology and petroleum geology studies. Generally, gamma ray, spontaneous-potential and resistivity well logs are utilized to qualitatively characterize variations in sediment grain size and determine the lithology in clastic reservoirs. However, grain size analysis of modern sedimentary samples collected from active rivers and deltas indicates that the percentage of fine depositional component has a logarithmic relationship with the average grain size in delta and river systems. Using the linear relationship to process the lithology interpretation, siltstones or mudstone is likely to be interpreted as sandstone. Therefore, a logarithmic conversion formula was built up between the gamma ray logs and measured grain size for the second member of the Xujiahe Formation of Anyue Area in the Sichuan Basin. Using the formula, the average grain size and lithology of the exploration wells were determined for the interest intervals. Furthermore, the calculated grain size gives a better understanding of the controlling factors of hydrocarbon-bearing reservoirs in the study area.

scholarly journals Comparative Grain-Size Measurements for Validating Sampling and Pretreatment Techniques in Terms of Solifluction Landforms, Southern Carpathians, Romania

2015 ◽  
Vol 8 (1-2) ◽  
pp. 39-47
Author(s):  
Raul David Serban ◽  
György Sipos ◽  
Mihaela Popescu ◽  
Petru Urdea ◽  
Alexandru Onaca ◽  
...  
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Diffraction Method ◽  
Sampling Procedure ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Important Indicator ◽  
Parallel Measurements ◽  
Southern Carpathians

AbstractGrain-size distribution has become in the last years an important indicator in the analysis of periglacial processes and landforms. However, as they exhibit a complex sedimentology, careful sampling is required to draw meaningful conclusions. The aim of the present study was therefore to validate the sampling procedure carried out on solifluction forms and to evaluate the effect of sampling pretreatment during grain size analysis. A comparison between multiple measurements of grain size distribution using the laser diffraction method (LDM) was performed on 54 sediment samples collected from different solifluction landforms at different depths in the alpine area of the Southern Carpathians. The results of parallel measurements were compared using textural and statistical indicators. The received distributions reinforced the properness of field sampling procedure in most of the cases. The results of textural classification and fractional composition showed a high consistency between the two parallel measurements made on untreated and pretreated samples. An overall fining as a matter of etching was identified. Relative deviation increased and correlation decreased as pretreatment advanced. HCl etching resulted a greater deviation and variability in case of the sand fraction, H2O2rather affected the silt fraction. The greatest deviations were experienced in case of landforms developed on crystalline limestone. Pretreatment of samples introduced a major uncertainty to further comparison and interpretation. Thus, multiple LD measurements on a representative group of samples from the entire sample set were suggested before the geomorphological or environmental interpretation of results to decrease the uncertainties and to validate the processes

scholarly journals Micro structural control of stabilized Zirconia ceramics (8YSZ) through modified conventional sintering methodologies

2010 ◽  
Vol 42 (1) ◽  
pp. 91-97 ◽  
Author(s):  
K. Rajeswari ◽  
Rajasekhar Reddy ◽  
U.S. Hareesh ◽  
B.P. Saha ◽  
R. Johnson
Keyword(s):  
Grain Size ◽  
Grain Growth ◽  
Structural Control ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Stabilized Zirconia ◽  
Average Grain Size ◽  
Conventional Sintering ◽  
Slip Cast ◽  
Rate Controlled

Slip cast Y2O3 stabilized Zirconia (8YSZ) ceramics was subjected to Conventional Ramp and Hold (CRH), Rate Controlled (RCS) and Two Stage Sintering (2SS) methodologies. Sintered samples were characterized for their densities and grain size analysis by Scanning Electron Microscopy. The slip cast samples sintered by CRH and 2SS have achieved 98 - 99 % of theoretical densities while RCS samples have exhibited a low density of 97 %. The samples exhibited an average grain size of 2.64 ?m by 2SS sintering in comparison to 8.83 ?m in case of CRH and 3.45 ?m in case of RCS. Controlled pore growth associated with RCS, when compared to CRH methodology is mainly responsible for the relatively smaller grain size observed with RCS. A four fold decrease in grain size i.e. 2.64 ?m observed with the two step sintering can be attributed to the fact that the first heating step to high temperature of 1550?C for a shorter duration closes the porosity without significant grain growth. The second step at 1375?C for a longer period of time imparts densification with limited grain growth.

Grain Size and Provenance of Bahia la Choya Sediments

1987 ◽  
Vol 2 ◽  
pp. 44-51 ◽  
Author(s):  
Lawrence T. Sumpter
Keyword(s):  
Grain Size ◽  
Tidal Flat ◽  
Volcanic Rocks ◽  
Heavy Minerals ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Rock Fragments ◽  
The North ◽  
Average Grain Size ◽  
Carbonate Shell

A grain size analysis (including the carbonate fraction) was performed on sediment samples from each of the following environments of Bahia la Choya: tidal flat, spit, beach, and estero. The sediments of the tidal flat have an average grain size of 2.88 phi, range from very well sorted to moderately well sorted, and have a carbonate shell fraction ranging from 1 to 30%. The spit sediments have an average grain size of 0.96 phi, are moderately to poorly sorted, and have a carbonate shell fraction of approximately 50%. The beach sediments have an average grain size of 1.22 phi, range from poorly sorted to moderately well sorted, and have a carbonate shell fraction of approximately 48%. The sediments of the estero average 39% sand, 40% silt, and 20% clay. The carbonate fraction in the estero is approximately 25%. The noncarbonate fraction in all the environments is made up of feldspar, quartz, biotite, heavy minerals, and igneous rock fragments.The major source for the sediment is the Pelican Point granite on the south side of the bay. Pleistocene rock in and around the bay provides a second source of sediment and volcanic rocks to the north may also contribute to the sediment.

scholarly journals Geochemical and Mineralogical Characterisation of Historic Zn–Pb Mine Waste, Plombières, East Belgium

Minerals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 28
Author(s):  
Srećko Bevandić ◽  
Rosie Blannin ◽  
Jacqueline Vander Auwera ◽  
Nicolas Delmelle ◽  
David Caterina ◽  
...  
Keyword(s):  
Grain Size ◽  
Mine Waste ◽  
Geophysical Methods ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Mine Wastes ◽  
Metallurgical Waste ◽  
High Concentration ◽  
Geochemical Properties ◽  
Potential Applications

Mine wastes and tailings derived from historical processing may contain significant contents of valuable metals due to processing being less efficient in the past. The Plombières tailings pond in eastern Belgium was selected as a case study to determine mineralogical and geochemical characteristics of the different mine waste materials found at the site. Four types of material were classified: soil, metallurgical waste, brown tailings and yellow tailings. The distribution of the mine wastes was investigated with drill holes, pit-holes and geophysical methods. Samples of the materials were assessed with grain size analysis, and mineralogical and geochemical techniques. The mine wastes dominantly consist of SiO2, Al2O3 and Fe2O3. The cover material, comprising soil and metallurgical waste is highly heterogeneous in terms of mineralogy, geochemistry and grain size. The metallurgical waste has a high concentration of metals (Zn: 0.1 to 24 wt.% and Pb: 0.1 to 10.1 wt.%). In the tailings materials, Pb and Zn vary from 10 ppm to 8.5 wt.% and from 51 ppm to 4 wt.%, respectively. The mining wastes comprises mainly quartz, amorphous phases and phyllosilicates, with minor contents of Fe-oxide and Pb- and Zn-bearing minerals. Based on the mineralogical and geochemical properties, the different potential applications of the four waste material types were determined. Additionally, the theoretical economic potential of Pb and Zn in the mine wastes was estimated.

scholarly journals Centennial Impacts of the East Asian Summer Monsoon on Holocene Deltaic Evolution of the Huanghe River, China

2021 ◽  
Vol 11 (6) ◽  
pp. 2799
Author(s):  
Yanping Chen ◽  
Wenzhe Lyu ◽  
Tengfei Fu ◽  
Yan Li ◽  
Liang Yi
Keyword(s):  
Grain Size ◽  
Yellow River ◽  
Asian Summer Monsoon ◽  
River Delta ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Sediment Grain Size ◽  
Huanghe River ◽  
Huanghe River Delta ◽  
The Huanghe River

The Huanghe River (Yellow River) is the most sediment laden river system in the world, and many efforts have been conducted to understand modern deltaic evolution in response to anthropological impacts. However, the natural background and its linkage to climatic changes are less documented in previous studies. In this work, we studied the sediments of core YDZ–3 and marine surface samples by grain-size analysis to retrieve Holocene dynamics of the Huanghe River delta in detail. The main findings are as follows: The mean value of sediment grain size of the studied core is 5.5 ± 0.9 Φ, and silt and sand contents are 5.2 ± 2.3% and 8.2 ± 5.3%, respectively, while the variance of clay particles is relatively large with an average value of 86.4 ± 8.5%. All grain-size data can be mathematically partitioned by a Weibull-based function formula, and three subgroups were identified with modal sizes of 61.1 ± 28.9 μm, 30.0 ± 23.9 μm, and 2.8 ± 1.6 μm, respectively. There are eight intervals with abrupt changes in modal size of core YDZ–3, which can be correlated to paleo-superlobe migration of the Huanghe River in the Holocene. Based on these observations, the presence of seven superlobes in the history are confirmed for the first time and their ages are well constrained in this study, including Paleo-Superlobes Lijin (6400–5280 yr BP), Huanghua (4480–4190 yr BP), Jugezhuang (3880–3660 yr BP), Shajinzi (3070–2870 yr BP), Nigu (2780–2360 yr BP), Qikou (2140–2000 yr BP), and Kenli (1940–1780 and 1700–1650 yr BP). By tuning geomorphological events to a sedimentary proxy derived from core YDZ–3 and comparing to various paleoenvironmental changes, we proposed that winter climate dominated Holocene shifts of the Huanghe River delta on millennial timescales, while summer monsoons controlled deltaic evolution on centennial timescales.

Predicting well productivity from grain size analysis and logging while drilling

1996 ◽  
Vol 2 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Andrew J. C. Hogg ◽  
Alan W. Mitchell ◽  
Susan Young
Keyword(s):  
Grain Size ◽  
Grain Size Analysis ◽  
Size Analysis ◽  
Well Productivity ◽  
Logging While Drilling
Sign in / Sign up

Export Citation Format

Share Document