The Tizapa Mine, an underground operation located in the State of Mexico, Mexico, has sustained its production for over 30 years through continuous exploration since its opening．This report re-evaluates exploration guidelines for the deep and peripheral extensions of the deposit̶the focus of recent efforts̶by integrating geochemical indicators and statistical analysis．First, the Alteration Index (Ishikawa et al., 1976), which was previously validated in shallow zones, was reexamined using recent drilling data．The results confirmed that elevated index values persist in the footwall of the deep and peripheral zones．Furthermore, while some barren drill holes penetrated areas with low alteration indices, a systematic review of this data clarified the exploration potential of ore body extensions and proved effective for refining target areas．Subsequently, a correlation matrix was generated for the assay grades and intersection lengths of the mineralized composites, and partial correlation coefficients were examined to clarify the intrinsic relationships among the elements within the mineralized zones．Furthermore, to objectively characterize the mineralization, a cluster analysis using a Gaussian Mixture Model was applied to the drill hole data．This revealed that the massive sulfide cluster is localized almost exclusively within the main Tizapa ore body．By integrating the Alteration Index with cluster analysis, a genetic hypothesis linking mineralized occurrences within the concession to the main Tizapa ore body was developed, leading to the successful identification of new highpotential exploration zones．The combination of these two methods is expected to serve as a robust indicator for both nearmine extension exploration and the evaluation of new mineralized prospects.

In a porphyry copper district in Chile where surficial cover layers composed predominantly of sand and gravel are widely distributed, we conducted a microtremor array survey to estimate the thickness of the cover. One-dimensional S-wave velocity (Vs) profiles were derived from observations at 24 sites within an area of approximately 2.0 km (E–W) by 2.5 km (N–S), yielding S-wave velocity structures to investigation depths of 300–1,000 m. Assuming Vs = 550 m/s as the S-wave velocity at the top of bedrock, the cover thickness was estimated to be 7–29.5 m. In addition, within the bedrock beneath the cover, distinct S-wave velocity contrasts were also identified near 1,500 m/s, 3,000 m/s, and 4,000 m/s. Among these, the 4,000 m/s isovelocity surface forms a NW–SE-trending depression in the central part of the study area, which is consistent with the inferred fault strike in the region and broadly coincides with the mineralization center proposed in existing ore-deposit models. These results suggest that the microtremor array survey may be applicable not only to estimating cover thickness but also as a geophysical tool for porphyry copper exploration. Future work should include comparison with drill cores and integrated interpretation with multiple geophysical datasets that account for three-dimensional effects, in order to evaluate the geologic and ore-deposit significance of the S-wave velocity boundaries.

To establish efficient exploration techniques for LCT pegmatites, exploration activities targeting pegmatites were conducted at the ML 198 concession in the Republic of Namibia and at the Mibra Mine in the Federative Republic of Brazil. In the remote sensing survey conducted at ML 198, direct extraction of lithium-bearing mica, a key mineralization indicator of LCT pegmatites, was performed. In addition, distribution maps of muscovite and kaolinite abundances were generated using a proprietary algorithm developed. Furthermore, supervised classification using an AI-based support vector machine (SVM) was applied to delineate areas interpreted as pegmatite dikes. The results demonstrated that the muscovite abundance map is effective for pegmatite exploration, and suggested that pegmatite dikes with a northeast–southwest trend are distributed over a broad area including the ML 198 region. Geological surveys conducted at ML 198 included surface geochemical line sampling, which revealed characteristic geochemical halos around the Northern Pegmatite and along the southern extension of the ore body. Geophysical surveys at ML 198 were carried out after selecting optimal survey parameters based on prior geophysical simulations. Although the pegmatite bodies were not directly delineated, partial results from the magnetic survey suggest the presence of a structure extending southward from the Northern Pegmatite. Based on the integrated results of these investigations, it is suggested that the Northern Pegmatite may continue southward beneath cover. Consequently, this area is recognized as upside exploration potential. At the Mibra Mine, drone-based surveys indicated that pegmatite bodies exposed within and around the mining pit are characterized by low magnetic anomalies and high potassium (K) values in gamma-ray spectrometry, accompanied by low thorium (Th), high F-parameter values, and reddish tones in RGB imagery. In contrast, small-scale pegmatites distributed in historical mining areas were difficult to directly extract using these geophysical datasets alone. Therefore, it is suggested that evaluating the potential occurrence of pegmatite bodies requires integrated interpretation combining geophysical results with complementary data such as topographic information, aerial photographs, and geological observations. In this study, a technical challenge was undertaken to examine the applicability of geophysical methods to pegmatite exploration, which has traditionally been considered difficult. Although severe constraints remain due to the narrow vein widths of pegmatites and the limited physical property contrasts with host rocks, the results suggest that integrated interpretation combining geological information with individual geophysical datasets can contribute as a supportive approach to pegmatite deposit exploration.

In the Southern Fossa Magna region in Japan, weak copper mineralization associated with the Pliocene (ca. 4 Ma) Kogarasu granodiorite is newly identified. In contrast to typical granitic rocks in Japan, the plagioclase in this granodiorite is exhibits excess Al suggesting metal fertility for ore mineralization. The hydrothermal alteration halo overprints both the Kogarasu granodiorite and the Miocene (ca. 13 Ma) Okusenjou-dake granodiorite. The alteration exhibits distinct concentric zoning, divided into three zones: a central potassic (potassium feldspar + magnetite) zone, a surrounding advanced-argillic alteration zone, and a peripheral chlorite zone. The advanced-argillic alteration zone hosts breccia pipe and silicified lithocaps, and the latter of which contain ore-grade enargite mineralization. The potassic zone is associated with minor disseminated chalcopyrite. The sericite K-Ar ages from the advanced argillic alteration zone are 5.41 ± 0.14 Ma and 4.28 ± 0.11 Ma, indicating that the hydrothermal system was genetically linked to the emplacement of the Kogarasu granodiorite. The trace element composition of hydrothermal magnetite in the potassic zone is consistent with the features of porphyry copper deposits (PCDs). These spatial alteration patterns and the presence of mineralized lithocaps indicate that this alteration corresponds to a PCD-type mineralization.