Isometric log-ratio transformation, Subcompositional coherence, Correspondence analysis, Principal component analysis, Geochemical compositional data, Polymetallic and porphyry deposits.
Abstract:
Each mineralization style is characterized by typical signature associations between elements due to elemental interactions, therefore the coherence and closure effects problem must be overcome in geochemical processing. The coherence indicates the ratios between two components (rows or columns) remains the same whether they are considered in a subcomposition or in the full composition. The log-ratio transformation (LRT) has recognized as a standard procedure to support subcompositional coherence. The log-transformed data is applicable for geochemical data to unveil such associations, prior to applying the multivariate analysis like correspondence analysis (CA) and principal component analysis (PCA). At the present study, subcompositional coherence is overcome by inverse iso-metric log-ratio transformation for geochemical compositional data at two polymetallic and porphyry deposits. Based on Ilr-transformed data, Ag, Au, As, Pb, Te, Mo and rather S, W, Cu are enriched as polymetallic elements at Glojeh, while Au-Cu-(Mo) compositions indicate a porphyry deposit occurred in Dalli deposit. The ability to handle zero values in the data matrix and determining an elemental eccentricity from the center of each axis based on Euclidean distances are the advantages of CA method, with compression to LRT. Whereas, loading factors which spread in every direction and providing subcompositional coherence are the competitive advantages of PCA based on LRT, for both case studies. Results with these techniques show significant ability to draw an inference in such geochemical data, and in improving the performance of multivariate techniques using LRT.
This study integrates geochemical, statistical, and machine learning methods to investigate hydrothermal systems and mineralization processes within southern Georgia’s Bektakari- Bnelikhevi ore knot. A total of 212 geochemical samples were analyzed, revealing key elemental associations such as V-Sc, Mo-W, and S-V, indicative of magmatic-hydrothermal activity and metasomatic alteration, including albitization and potassic enrichment. Principal Component Analysis (PCA) and DBSCAN clustering identified two dominant alteration regimes: Sulfide-rich mineralization and alkali metasomatism. Geochemical indices, Alteration Index (AI) and Chlorite- Carbonate-Pyrite Index (CCPI), effectively delineate alteration zones. AI values ranged from 45 to 95, while CCPI ranged from 30 to 85, with the highest mineralization potential concentrated in sericitic and Na-Ca zones. Feature importance analysis highlighted the Cu-Ag-Pb Index (32%) and Metallicity Factor (27%) as the strongest predictors of mineralized zones. Machine learning models achieved high precision in identifying epithermal and porphyry zones (Precision > 0.85), though recall remained low in transitional areas (Recall ~0.38), suggesting underrepresentation or overlapping features in these zones. This integrated approach offers a data-driven framework for targeting hydrothermal mineralization. The findings can inform exploration strategies by prioritizing geochemical signatures and improving zone classification in complex alteration systems.
Evaluation of the alternatives for gold ore grinding circuits by using of laboratory studies results and simulation method; case study: İranian Gold Co.
In this study, simulation aided design of grinding circuit for a gold mine in Iran is presented. The main parameters for the design of the grinding circuit are the ore specifications and the considered operating conditions. Ore specifications were characterized by grinding tests, which included the Drop – weigh test (A, b), the abrasion test (ta) and the Bond Work Index test (Wi). For this study, the operating conditions for the processing plant are the ability to process clayey minerals and the plant throughput and the d80 of the hydrocyclone overflow (leaching tank feed), which are 125 tons per hour and 45 μm, respectively. Simulation operations were performed using grinding parameters (A, b, ta, Wi), operating constraints (plant capacity, d80 of the hydrocyclone overflow and ability to work for clayey minerals), existing mathematical models for different types of crushers, mills and separators and JKSimMet software. By completing the simulation process, three different alternatives for the grinding circuit of the considered ore were predicted. These three alternatives have been compared and evaluated with each other in terms of specific energy consumption (kWh/t), sensitivity to operational variables and the ability to process clayey minerals. The optimal circuit must have the capability to process clayey minerals and must have the lowest specific energy consumption and the least sensitivity to operational variables. By considering all these factors, the Alternative 3 is selected and suggested for an efficient grinding circuit.
https://doi.org/10.19111/bulletinofmre.501432
A brief note on the effects of floating standard deviation (non- derivative) and horizontal gradient (derivative) filters
Authors:
Ceyhan Ertan TOKER
ABSTRACT
When processing gravity data, the filters are used in space and frequency environments. The filters allow more selectable parameter estimations than raw data about the structure being examined. Filtering in a broad sense means monitoring the data under the constraints we want. While the filters allow some information to become more noticeable, they allow some information to be lost or become less noticeable from data. In this case, the losses in the data make the interpretation difficult and can cause errors. Derivative and phase filters provide quantitative information about the variation of data in different directions. The display of the change results in a positive or negative manner proportional to derivative sensitivity and phase sharpness, and this may be observed in this data. In the structural boundary analysis, since the sudden changes in the derivative cause oscillations, the boundaries become questionable. Limiting the data neighborhoods with a window by controlling the deviation without using derivative and the filters that allow boundary analysis non-derivative by floating this limitation are used to illuminate the boundary relationships.
https://doi.org/10.19111/bulletinofmre.546153
Keywords:
Gravity, Filter, Standard deviation, Long wavelength, Nonderivatives.
Hüseyin ÖZTÜRK, Nurullah HANİLÇİ, Sinan ALTUNCU, Cem KASAPÇI
Indexed In · Volume 159 / 2019
Rare earth element (REE) resources of Turkey: An overview of their characteristics and origin
Authors:
Hüseyin ÖZTÜRK, Nurullah HANİLÇİ, Sinan ALTUNCU, Cem KASAPÇI
ABSTRACT
The Rare Earth Elements (REE) deposits and mineralization of Turkey can be divided into four types based on their geological setting and origin. First are deposits associated with carbonatite- alkaline magmatic rocks, rich in Light Rare Earth Elements (LREE). The best known examples are the Kızılcaören (Eskişehir) and Kuluncak (Malatya) deposits with TREE grades of 2.9% and 0.7% respectively, and typical enrichment of La-Ce. Lower grade REE mineralization at Keban (0.05% TREE) and Divriği (0.13% TREE) is associated with abundant fluorite and all four occurrences show similar ranges for homogenization temperatures and salinities for fluid inclusions in fluorite and REE profiles. The second type are Triassic shales and the bauxites formed from them in the Bolkardağı region. Enrichment of Heavy REE (HREE) is typical and TREE grades are about 0.15% in bauxites and its protolith. These occurrences are geochemically similar to “ion adsorption type” deposits associated with lateritic clay on the weathered granitic rocks of China. Third is the placer type, represented by the Çanaklı (Burdur) deposit which is enriched in U, Th and HREE and heavy minerals such as; magnetite, zircon and rutile and has an average grade of about 0.08% TREE. The fourth potential source of REE is phosphorites. These rocks host the world’s largest resources elsewhere, however the Cretaceous Mazidag deposits in Turkey are very low grade (40ppm TREE) and clearly uneconomic. Consideration of the environmental and health issues associated with exploitation and processing of REE has identified the more favorable outcomes associated with exploitation of the ion adsorption type of deposits and justification for further evaluation of the resources and processing technologies that would enable exploitation of REE-enriched bauxites in the Bolkardağı region.
https://doi.org/10.19111/bulletinofmre.471205
Keywords:
Rare earth element geochemistry, Carbonatite, Shale, Bauxide, Turkey.
