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Mineralogical factors affecting the separation behavior of Ta-Nbbearing minerals in the gravity field : mineral grain size, liberation, and association relationship

Cheng Hongwei, Xu Jian, Wang Shoujing, Lv Zihu, Wei Fushuai, Zhao Dengkui, Wu Dongyin

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 6

art. no. 174504

EN

Gravity separation is the primary method used to beneficiate Ta-Nb-bearing minerals, however, it performs poorly in low-grade and fine-grained ores. A comparative study of gravity separation products (concentrate, middlings, and tailings) reveals the factors affecting the separation behavior of Ta-Nb-bearing minerals in the process combined with a spiral chute and shaking table from the perspective of mineralogy. The results reveal that columbite-tantalite is the principal Ta-Nb-bearing mineral. As the grinding time increases, the grade of Ta and Nb in concentrate increases significantly. The grain size of columbite-tantalite in the concentrate is the coarsest, followed by that in the middlings, and the finest in the tailings, which are mainly distributed in the range of -150+38 μm, -75+20 μm, and -38 μm, respectively. The liberation degree of columbite-tantalite in the concentrate and tailings is positively correlated with grinding time, while that in the middlings is negatively correlated with grinding time. The density of columbite-tantalite-bearing particles in concentrate is mainly distributed above 3 or even 4, due to the high liberation degree of the columbite-tantalite in the concentrate, as well as the high amount of rich intergrowth associated with heavy minerals. The density of Ta-Nb-bearing mineral particles in the middlings and tailings is predominantly distributed in D<3, owing to columbite-tantalite mainly associated with lighter gangue minerals such as quartz, albite, and orthoclase. It demonstrates that the liberation degree is not the most essential factor in determining columbite-tantalite separation behavior in the gravity field, and the mineralogical characteristics of columbite-tantalite including grain size, association relationship, and particle density, may be more important. The results of this investigation can provide theoretical support for the strengthening separation of low-grade tantalum-niobium ore.

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Segmentation of Homogeneous Regions of Gravity Field Properties by Machine Learning Method in Central Area of Vietnam

Thi Hong Phan, Minh Phuong Do, Van Huu Tran

Inżynieria Mineralna

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2023

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no. 2, vol. 1

97--102

EN

This paper presents the results of applying the unsupervised learning method (K-means clustering) on the gravity anomaly field in the central region of Vietnam to separate the research area into different clusters, which are homologous in physical properties. In order to achieve the optimal results, the input parameter plays an important role. In this paper, we chose 04 input attributes including the gravity anomalous field attribute, the horizontal gradient attribute, the variance attribute, and the tracing coefficient of the gravity anomalous axis. The obtained results have shown that the research area could be divided into 7 clusters, 9 clusters, 11 clusters, and 13 clusters with close characteristics of the physical properties of the gravity field. The research results show that the Southwest, the Center, and the South of the study area have complex changing physical properties, this result reflects the complicated tectonic activities in these areas with the presence of crumpled and fractured rock layers in different directions and these locations are the potential places to form endogenous mineral deposits of magma origin. The Northwest, the North, and the East parts of the research area witness negligible changes in the field's physical properties, reflecting the stability of the soil and rock layers in this area, with the direction of extending structure from the Northwest to the Southeast. The clustering results according to the K-means unsupervised learning algorithm in central Vietnam initially increase the reliability of the decisions of geologists and geophysicists in interpreting the geological structure and evaluating the origin of deep-hidden mineral deposits in the area.

3

Research on gravity field modelling and gravimetry in Poland in 2019–2022

Krynski Jan, Dykowski Przemysław, Godah Walyeldeen, Szelachowska Małgorzata

Advances in Geodesy and Geoinformation

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2023

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Vol. 72, no. 2

art. no. e46, 2023

EN

The article presents the reviewed and summarised research activities of the Polish research groups on gravimetry and gravity field modelling in the period of 2019–2022. It contains the results of absolute gravity surveys for the maintenance of the international gravity reference level in Poland and Europe, and for geodynamic research with an emphasis on metrological aspects. It also contains relative gravimetry issues as well as the results of marine gravity surveys in the southern Baltic Sea. Non-tidal gravity changes were extensively investigated. Long-term gravity variations were monitored at the Borowa Gora Geodetic-Geophysical Observatory and in a few other locations in Poland. The contribution of gravimetric records to seismic studies was investigated. Temporal variations of the gravity field from GRACE (Gravity Recovery and Climate Experiment) and GRACE-FO (GRACE Follow-On) data, in particular, deformations of the Earth’s surface as well as temporal variations of heights, total water storage and groundwater storage were investigated. Moreover, GRACE-based products and the performance of monthly Global Geopotential Models (GGMs) were a subject of research. GGMs developed in last years were evaluated. The research on developing new approaches in geoid modelling and their validation was conducted. New regional and local geoid models were determined for Poland and Ethiopia. The use of different techniques for estimating the absolute sea level at sites of the selected network in the Baltic Sea was investigated.

4

Research on gravity field modelling and gravimetry in Poland in 2015–2018

Krynski Jan, Dykowski Przemysław, Olszak Tomasz

Geodesy and Cartography

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2019

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Vol. 68, no. 1

31--63

EN

Activities of the Polish research gSDroups concerning gravity field modelling and gravimetry in a period of 2015–2018 are reviewed and summarised in this paper. The summary contains the results of research on the evaluation of GOCE-based global geopotential models (GGMs) in Poland and geoid modelling. Extensive research activities are observed in the field of absolute gravity surveys, in particular for the maintenance of national gravity control in Poland, Sweden, Denmark, the Republic of Ireland and in Northern Ireland as well as for geodynamics with special emphasis on metrological aspects in absolute gravimetry. Long term gravity variations were monitored in two gravimetric laboratories: the Borowa Gora Geodetic-Geophysical Observatory, and Jozefoslaw Astrogeodetic Observatory with the use of quasi-regular absolute gravity measurements as well as tidal gravimeter records. Gravity series obtained were analysed considering both local and global hydrology effects. Temporal variations of the gravity field were investigated using data from GRACE satellite mission as well as SLR data. Estimated variations of physical heights indicato the need for kinematic realization of reference surface for heights. Also seasonal variability of the atmospheric and water budgets in Poland was a subject of investigation in terms of total water storage using the GLDAS data. The use of repeatable absolute gravity data for calibration/validation of temporal mass variations derived from satellite gravity missions was discussed. Contribution of gravimetric records to seismic studies was investigated. The bibliography of the related works is given in references.

5

Rotation, initial stress, gravity and electromagnetic field effect on P wave reflection from stress-free surface elastic half-space with voids under three thermoelastic models

Abo-Dahab S. M., Rida S. Z., Mohamed R. A., Kilany A. A.

Mechanics and Mechanical Engineering

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2018

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Vol. 22, nr 1

313--328

EN

The present paper is devoted to investigate the influence of the rotation, thermal field, initial stress, gravity field, electromagnetic and voids on the reflection of P wave under three models of generalized thermoelasticity: Classical and Dynamical coupled model (CD), Lord-Shulman model (LS), Green-Lindsay model (GL), The boundary conditions at stress-free thermally insulated surface are satisfied to obtain Algebraic system of four equations in the reflection coefficients of various reflected waves. It is shown that there exist four plane waves; P1, P2, P3 and P4. In addition, the reflection coefficients from insulated and isothermal stress-free surface for the incident P wave are obtained. Finally, numerical values of the complex modulus of the reflection coefficients are visualized graphically to display the effects of the rotation, initial stress, gravity field magnetic field, thermal relaxation times and voids parameters.

6

Comments on "Archives of Civil and Mechanical Engineering 17 (2017) 564–573"

Pantokratoras A.

Archives of Civil and Mechanical Engineering

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2018

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Vol. 18, no. 4

1643--1644

EN

The present comment concerns some doubtful results included in the above paper.

7

Hydrogeologiczne przyczyny zmian przyspieszenia siły ciężkości na stanowisku w Obserwatorium Astronomiczno-Geodezyjnym w Józefosławiu

Olszak T., Barlik M., Pachuta A.

Przegląd Geologiczny

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2017

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Vol. 65, nr 11/1

1139--1143

EN

The article presents the results of measurements of gravity performed in the Astronomical and Geodetic Observatory Józefosław. Time series have been verified for parameters related to celestial bodies, atmospheric pressure changes and metrological factors. The analysis of these changes includes geodynamic and hydrological aspects taking into account global and local changes in groundwater levels. The aim of the article is to indicate the interpretation of contemporary measurements of gravity field against the contemporary accuracy of such measurements and to indicate the need for information on the level of groundwater (collected by the Polish Hydrogeological Survey) in procedures for the elaboration and interpretation ofgravimetric measurements and supportfrom hydrogeologists. Contemporary the gravity measurements with use of absolute gravimeters gives possibility determination of gravity value with uncertainty of the order 10-8 ms-2. Such accuracy corresponds to a vertical displacement of a point of less than 1 cm or a change in the water level of 2.5 cm. Use of gravimetric methods in the broadly understood Earth sciences must be supported by information related to changes in mass distribution around the measuring station, mainly related to the groundwater level changes. This allows to see the role of hydrogeological information related to the monitoring of groundwater as an indispensable information describing changes in the Earth’s gravity field.

8

Propagation of a thermoelastic wave in a half-space of a homogeneous isotropic material subjected to the effect of gravity field

Abd-Alla A. M., Abo-Dahab S. M., Alotaibi H. A.

Archives of Civil and Mechanical Engineering

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2017

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Vol. 17, no. 3

564--573

EN

The propagation of thermoelastic waves in a homogeneous, isotropic elastic semi-infinite space is subjected to a gravitational field, which is at temperature T0 initially, and whose boundary surface is subjected to heat source and load moving with finite velocity. Temperature and stress distribution occurring due to heating or cooling and have been determined using certain boundary conditions. Numerical results have been given and illustrated graphically in each case considered. The results indicate that the effect of gravity field is very pronounced. Comparison is made with the results predicted by the theory of thermoelasticity in the absence of gravity. The results indicate that the effect of the gravity is very pronounced.

9

Gravity field modelling and gravimetry

Krynski J.

Geodesy and Cartography

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2015

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Vol. 64, no. 2

177--200

EN

The summary of research activities concerning gravity field modelling and gravimetric works performed in Poland in the period of 2011-2014 is presented. It contains the results of research on geoid modelling in Poland and other countries, evaluation of global geopotential models, determination of temporal variations of the gravity field with the use of data from satellite gravity space missions, absolute gravity surveys for the maintenance and modernization of the gravity control in Poland and overseas, metrological aspects in gravimetry, maintenance of gravimetric calibration baselines, and investigations of the nontidal gravity changes. The bibliography of the related works is given in references.

10

Quasigeoid for the area of Poland computed by least squares collocation

Łyszkowicz A.

Technical Sciences / University of Warmia and Mazury in Olsztyn

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2010

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nr 13

147-164

EN

The quasigeoid models recently computed in Poland e.g. (Łyszkowicz, Kryński 2006) and abroad e.g. (Al Marzooqi et al. 2005) were computed from Stokes'a integral by Fast Fourier Technique (FFT). At present because of significant capability of personal computers and proper strategy of computation more often for geoid/quasigeoid computation the least squares collocation is used. In the present paper is described the first quasigeoid computation by least collocation for the area of Poland. The quasigeoid model was computed in two version, namely from the gravity data only and from the gravity and vertical deflections data simultaneously. The differences between these two versions are small and do not exceed 1-2 mm. In order to evaluate the advantages coming from the collocation the third pure gravimetric model using Stokes'a integral was computed and compared with the gravimetric model computed by collocation. The differences between these versions are significant and at the level of 20 cm, beside the collocation model is better.

PL

Wszystkie ostatnio liczone grawimetryczne modele quasi-geoidy w Polsce (np. Łyszkowicz, Kryński 2006) i na świecie (np. Al Marzooqi et al. 2005) były liczone na podstawie całki Stokesa, do której oszacowania wykorzystywano szybką transformatę Fouriera (FFT). Obecnie ze względu na znaczne możliwości komputerów oraz odpowiednio opracowaną strategię obliczeniową coraz częściej do wyznaczenia przebiegu geoidy/quasi-geoidy wykorzystuje się metodę kolokacji. W pracy przedstawiono pierwsze w Polsce wyznaczenie przebiegu quasi-geoidy metodą kolokacji. Model quasi-geoidy wyznaczono w dwóch wariantach, a mianowicie tylko z danych grawimetrycznych, a następnie łącznie z danych grawimetrycznych i astro-geodezyjnych odchyleń pionu. Różnice między tymi dwoma wariantami są minimalne i wynoszą 1-2 mm. W celu oceny korzyści wynikających z metody kolokacji grawimetryczną quasi-geoidę policzono również metodą FFT i porównano z quasi-geoidą obliczoną metodą kolokacji. Z przeprowadzonego porównania wynika, że rozbieżność między modelami jest rzędu 20 cm, z tym że quasi-geoida kolokacyjna jest lepsza.

11

Influence of magnetic field on heat transfer in ferrofluid

Stręk T.

Vibrations in Physical Systems

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2006

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Vol. 22

331--336

12

Investigation of Hungarian torsion balance measurements by prediction

Tóth G., Völgyesi L.

Reports on Geodesy

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2005

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z. 2/73

277-284

EN

Torsion balance measurements in Hungary were checked by least-squares collocation. The methodology was the so-called "leave-one-out" prediction of horizontal gravity gradients. The method was succesfully tested on a selected subset of 700 torsion balance measurements and only three possible outliers has been detected. These results are promising in view of a planned new Hungarian geoid determination.

13

Geophysical cartography in Poland : an overview

Krzywiec P., Nawrocki J., Polechońska O., Wróblewska M.

Przegląd Geologiczny

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2005

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Vol. 53, nr 10/2

967-972

EN

Regional analysis and mapping of various geophysical data has been recognized as an important — even crucial — element of geological studies for many years. Due to rapid development of advanced numerical tools it is presently possible to construct, maintain and comprehensively analyse even very large geo-databases, including seismic, gravity, magnetic, geothermal and other geophysical data. In many countries, national geological surveys, commercial companies and research institutions are involved in mapping projects focused on spatial representation of geophysical data that could later be used for various studies. Recently, new policy of the Polish Ministry of Environment regarding geological cartography in years 2005–2020 has been declared (cf. Ber & Jezierski, 2004). In this document, geological cartography is used as a rather wide term that includes also other geo-disciplines like geoenvironmental studies or surface geochemistry. Among them, mapping of geophysical data is also mentioned. In this paper, short overview of the current state-of-the-art of selected aspects of regional geophysical mapping in Poland is given, with some remarks regarding potential directions of future work.