Petrographic characteristics in the central part of Kosovo

Purpose. This paper aims to provide complete identification of rock types in the Drenas region by detailed description of all types of the rocks found. The authors intended to determine interruption or continuity of all inter-formational boundaries to accurately delineate them on the ground and fully reflect on the 1: 25000 scale map, as well as to identify the nature of contact between rock types and give its detailed description. Methods. During August, September, October of 2019, the exploration field trips were carried out. Geological survey works focused on the following areas: complete identification of all rock types on the basis of studying their samples, preparation of thin sections for petrographic (only the magmatic rock), chemical and geochemical analysis. Systematic measurement of structural elements was conducted alongside with identification and description of mineral outcrops areas. Findings. Based on the study of stratigraphic units and geological description of mineral outcrop areas, we identified different types of rocks using petrography microscope preparation and chemical and geochemical analysis. The area of Drenas has the following lithostratigraphic units: gabbro diabase, harzburgite, metasandstone. Originality. The originality of the study consists in the use of optical microscope for precise identification of rocks. As a result of the research conducted in the exploration area, we have obtained a clear petrographic description of minerals composition, their texture and mineralization, which allows assessing the possibility of the area exploitation. The analyses were completed at the certified laboratory of Geology-Mining Faculty (Polytechnic University of Tirana) and Geosciences Institute. Practical implications. Petrographic study and chemical analysis led to the conclusion that the research area has Ni mineralization, which is important for the development of mining sector and the community given the environment is preserved and the adequate way of the area exploitation is applied.

Study on the Geohazard Distribution Laws and Hazard-Causing Mechanism in Menghai County of Yunnan Province

study area is located at the southwest border of Yunnan Province and the southward extended part of Nushan Mountain, with complex and fragile geo-environmental conditions. Deep geological survey and mathematical analytical investigation on the geohazard distribution and hazard-causing mechanisms in this area were carried out in this study. The results revealed that: (1) The development of geohazards was affected differently by different slope shapes, slope structures and elevations; (2) Most of the geohazards were developed in medium shallow cut ridge-like medium-height mountainous geomorphological region and shallow cut steamed bun-like low and medium-height mountainous geomorphological region, and they were relatively concentrated on tectonic zones like fault zones; (3) The slopes formed by loose earth piling up on the surface of Indo-Chinese magmatic rock and Lancang Group metamorphic rock formations were most prone to slope instability and even landslide. The deep study on the geohazard distribution and hazard-causing mechanisms can provide geoscientific basis and reference for the prevention and mitigation work of geohazards under similar geo-environmental conditions.

Study on Electrical Characteristics of Magmatic Rock Intrusions in Metamorphic Rock Formations—Taking the Mupi Tunnel of Jiuzhaigou-Mianyang Highway as an Example

The stratum lithology and geological structure of the highway tunnel in the mountainous areas of western China are complex, and the engineering geological conditions are complicated. When the highway tunnel passes through different lithological strata, its structural design and construction are completely different. Therefore, the design and construction of the supporting tunnel are used in the tunnel survey. The identification of the contact boundary between magmatic rock and metamorphic rock and the grade of surrounding rock is very important. The data processing, forward numerical simulation, 1D, 2D, and 3D inversion of the G8513 Jiuzhaigou-Mianyang Expressway Mupi Tunnel survey by magnetotelluric method reveals the ground level along the design line of the tunnel to the depth of 50m depths within the design elevation of the tunnel. Electrical characteristics, focusing on the identification of the contact boundary between magmatic rock and metamorphic rock. This study provides the electrical characteristics of the magmatic rock and metamorphic rock contact boundary of the Mupi Tunnel. It is speculated that the boundary is revealed by the tunnel construction excavation, which verifies the correctness of the geophysical inversion model and provides a more detailed design basis for the tunnel design. It is believed that taking the Mupi tunnel survey as an example, this research can provide detailed geophysical basis for the identification of magmatic rock and metamorphic rock in highway tunnels, as well as the geological survey and design of highway tunnels.

Breaking and Instability Movement Characteristics of High-Position Double-Layer Hard Thick Strata due to Longwall Mining

With multilayer hard roof occurring above the mining area, the strata behaviors will be significantly affected by their special characteristics and interaction. In this paper, relying on the mining background of panel 1061 of a coalmine, the breaking instability of double-layer hard thick strata (DLHTS) and the precursory information of disasters are studied by using theoretical analysis, numerical simulation, and physical simulation. Results show that the DLHTS have bearing, blocking, and controlling effects. Prior to DLHTS breaking, the horizontal development of stress concentration zone and plastic zone can be controlled, and the overburden movement is gentle, while during the breaking process, the stress drops abruptly, the plastic zone expands longitudinally rapidly, the overburden moves notably, and the energy release is sharp, which is likely to directly cause strong dynamic pressure. Moreover, the DLHTS can interact with and influence each other; that is to say, the breaking of lower magmatic rock (LMR) can provide sufficient space for that of upper magmatic rock (UMR), while the UMR breaking can promote the LMR periodic breaking in turn and cause its secondary instability, thereby easily causing complex or composite dynamic disasters’ formation. Hence, compared with single hard thick stratum occurrence, the strata behaviors affected by DLHTS breaking and instability are normal and more intense. Study results can provide a scientific basis for the prevention and control of dynamic disaster with hard thick stratum occurrence and important guidance value for promoting safe and efficient production of coalmines.

Material composition of the kursov’s assise of the vendian period of the Mirnin outshot of the Nepsk-Botuobinsk anteclise according to the results of the core material study

In this work, the object studied is the terrigenous and carbonate rocks of the Kursov’s assise of the Nepsk horizon of the Botuobinsk facies zone of the Mirnin outshot of the north-eastern part of the Nepsk-Botuobinsk anteclise. In recent years, in the course of active geological exploration work in the region, high quality core material appeared. This material was studied at the macro and micro levels, which made it possible to obtain new data on the material composition. Based on the detailed lithological description and petrographic core study, for the first time, the author gives a description and justification of the division of the Kursov’s assise into three lithological packs: low clay sand, middle carbonate clay and high carbonate clay sand. The lithological properties of the studied section reflect the characteristics of the Vendian deposition of sediments in the south of the Siberian paleocontinent. The accumulation of sandstones of the Kursov’s assise was facilitated by the weathering of magmatic rock of acidic and medium composition; the destruction products that came from the north-western part to the south-eastern part of the NepskBotuobinsk anteclise in the modern plan. In the upper-section of the Kursov’s assise, the gradual increase in the maturity of terrigenous rocks, which is associated with the duration of their transportation and repeated redeposition, is observed. The carbonate microbial formations of the middle pack of the Kursov’s assise are the first witnesses to life in the Vendian paleobasin. Their characteristic feature is the magnesia impurity.

Analysis of Overlying Strata Movement and Disaster-Causing Effects of Coal Mining Face under the Action of Hard Thick Magmatic Rock

When the hard and thick key strata are located above the working face, the bed separation structure is easy to be formed after mining because of the high strength and integrity of the hard and thick key strata and the initial breaking step is large. After the hard, thick strata are broken, the overburden will be largely collapsed and unstable in a large area and the dynamic disaster is easily induced. In this study, considering the fundamental deformation and failure effect of coal seam, the development law of the bed separation and the fractures under hard and thick magmatic rocks and the mechanism of breaking induced disaster of hard and thick magmatic rocks are studied by similar simulation tests. The results of the study are as follows: (1) The similar material ratio of coal seam is obtained by low-strength orthogonal ratio test of similar materials of coal seam, that is, cement:sand:water:activated carbon:coal = 6:6:7:1.1:79.9. (2) The magmatic rocks play a role in shielding the development of the bed separation, which makes the bed separation beneath the magmatic rock in an unclosed state for a long time, providing space for the accumulation of gas and water. (3) The distribution pattern of the fracture zone shows different shapes as the advancing of working face and the fracture zone width of the rear of working face coal wall is larger than that of the front of the open-off. (4) The breaking of magmatic rocks will press the gas and water accumulated in the bed separation space below to rush towards the working face along the fracture zone at both ends of the goaf. The above results are verified through the drainage borehole gas jet accident in the Yangliu coal mine. The research results are of great significance for revealing the occurrence process of dynamic disasters and adopting scientific and reasonable preventive measures.