• Economic and Environmental Geology
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• v.54 no.5
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• pp.573-580
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• 2021

This study analyzed the induced effects of the aggregate and stone sectors using the industry association table. First, the added value of the aggregate and stone sectors was summarized, and then the intermediate input structure and induced effect were analyzed. In terms of value-added structure, aggregate and stone showed a higher employee remuneration rate compared to the manufacturing industry, and a higher rate of operating surplus compared to other mining industries. The intermediate input structure summarizes the sector using aggregate and stone products as intermediate inputs and their input ratio. The proportion of the intermediate element input structure was confirmed. In addition, the main input sectors of ready-mixed concrete, the largest consumer of aggregate and stone, are also summarized. The production-inducing effect of aggregate and stone showed a higher influence coefficient than the sensitivity coefficient, confirming that they had a relatively large rear chain effect. The production inducement effect was reviewed by reconstructing the industry association table, and it was found to show a relative superiority in the influence coefficient, similar to the results derived according to the provisional classification of the Bank of Korea.

• Journal of the Korean earth science society
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• v.40 no.2
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• pp.163-176
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• 2019

The Potosinian geological basement in central Mexico is comprised of the Upper Paleozoic metamorphic rocks, which crop out on the Sierra de Catorce nucleus located in the northeastern part of the state. The sedimentary sequence that covers unconformably the Paelozoic basement is represented by an Upper Triassic marine sedimentary sequence, correlating to the Zacatecas Formation and the Upper Triassic continental Huizachal Formation red beds, which in turn are covered either by La Joja Formation Jurassic red beds or by Upper Jurassic marine sediments. This sequence is overlain by the conformable Cretaceous calcareous marine sedimentary rocks in all the state of San Luis Potosi. The Cenozoic sequence unconformably covers some of the aforementioned rocks and is represented by undifferentiated volcanic rocks as well as by marine clastic rocks. The existing intrusive igneous rocks are felsic to intermediate composition, and they intrude the metamorphic basement and sedimentary rocks. Conglomerates with evaporitic sediments were deposited during the Pleistocene. The Quaternary sequence includes basalt flows, piedmont deposits, alluvium, and occasionally evaporites and caliche layers. In the state of San Luis Potosi, a great diversity of mineral deposit types is known as both metallic and nonmetallic. The host rocks of these deposits vary from one another including formations that represent from Paleozoic up to Tertiary. The mineralization age corresponds approximately to Tertiary (75%), and is mainly epigenetic. Conclusively, the data on geology and mineralization in San Luis Potosi, Mexico are helpful to predict a hidden ore body and select promising mineralized zone(s) when the domestic company makes inroads in the mining sector of Mexico.

• Journal of the Mineralogical Society of Korea
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• v.32 no.2
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• pp.87-102
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• 2019

Pallancata Ag mine is located at the Ayacucho region 520 km southeast of Lima. The geology of mine area consists of mainly Cenozoic volcanic-intrusive rocks, which are composed of tuff, andesitic lava, andesitic tuff, pyroclastic flow, volcano clasts, rhyolite and quartz monzonite. This mine have about 100 quartz veins in tuff filling regional faults orienting NW, NE and EW directions. The Ag grades in quartz veins are from 40 to 1,000 g/t. Quartz veins vary from 0.1 m to 25 m in thickness and extend to about 3,000 m in strike length. Quartz veins show following textures including zonation, cavity, massive, breccia, crustiform, colloform and comb textures. Wallrock alteration features including silicification, sericitization, pyritization, chloritization and argillitization are obvious. The quartz veins contain calcite, chalcedony, adularia, fluorite, rutile, zircon, apatite, Fe oxide, REE mineral, Cr oxide, Al-Si-O mineral, pyrite, sphalerite, chalcopyrite, galena, electrum, proustite-pyrargyrite, pearceite-polybasite and acanthite. The temperature and sulfur fugacity ($f_{s2}$) of the Ag mineralization estimated from the mineral assemblages and mineral compositions are ranging from 118 to $222^{\circ}C$ and from $10^{-20.8}$ to $10^{-13.2}atm$, respectively. The relatively low temperature and sulfur-oxygen fugacities in the hydrothermal fluids during the Ag mineralization in Pallancata might be due to cooling and/or boiling of Ag-bearing fluids by mixing of meteoric water in the relatively shallow hydrothermal environment. The hydrothermal condition may be corresponding to an intermediate sulfidation epithermal mineralization.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.1
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• pp.75-81
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• 2022

Given that China's resource research, exploration and development and resource economy policies are closely related to Korea's industrial competitiveness in the field of global mineral energy resources, it is important to establish the domestic and overseas resource development strategies. In 2020, China will revise and set standards for mineral resources to ensure efficiency in exploration and development and storage management. China's Ministry of Natural Resources has established the National Mineral Resources Plan (2021-2025), aiming to achieve national goals and strategies, and local governments at all levels are also establishing and implementing regional mineral resources plans. As a result, the supervision and management of geological mineral exploration activities have been strengthened, and the safety of industrial production management in the field of geological mineral exploration and development has been strengthened. China has developed guidelines for high-quality geological exploration, surveying and mapping, improved the level of geological mineral exploration and strengthened the mining supervision and management system. According to China's standardization of mineral resources such as solid mineral resources and petroleum gas mineral resources, a new standard system for resource management will be established in China to improve scientific understanding, rational management and utilization.

• Tunnel and Underground Space
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• v.32 no.1
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• pp.78-92
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• 2022

In this study, we proposed a diagnostics and assessment model for mining sites that can evaluate the smart mining technology level in a systematic and structured way. For this, the maturity of the smart mining was defined, and detailed assessment items of the diagnostics and assessment model for smart mining were derived by considering the smart factory diagnostics and assessment model (KS X 9001-3) used in the manufacturing industry. While maintaining the existing system, the existing 46 detailed assessment items were modified to be suitable for mining. As a result, a total of 29 detailed assessment items were derived in the areas of promotion strategy, process, information system and automation, and performance. Based on this, a questionnaire was designed to diagnose the level of smart mining technology, and assessment was performed by applying it to domestic iron mines. The level of smart mining technology in the study area was found to be level 2, and it could be inferred that it was about 40% lower than the average smart level of the general manufacturing industry. In addition, by using the developed model, it was possible to recognize the weak points of the mine at each stage of the introduction, operation, and advancement of smart mining, and to suggest investment and improvement directions.

• Tunnel and Underground Space
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• v.32 no.6
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• pp.451-463
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• 2022

Whenever a mineshaft accidentally collapses, speedy risk assessment is both required and crucial. But onsite safety diagnosis by humans is reportedly difficult considering the additional risk of collapse of the unstable mineshaft. Generally, drones equipped with high-speed lidar sensors can be used for such inspection. However, the drone technology is restrictively applicable at very shallow depth, failing in mineshafts with depths of hundreds of meters because of the limit of wireless communication and turbulence inside the mineshaft. In previous study, a three-dimensional (3D) scanning system with a single channel lidar was fabricated and operated using towed cable in a mineshaft to a depth of 200 m. The rotation and pendulum movement errors of the measuring unit were compensated for by applying the data of inertial measuring unit and comparing the similarity between the scan data of the adjacent depths (Kim et al., 2020). However, the errors grew with scan depth. In this paper, a multi-channel lidar sensor to obtain a continuous cross-sectional image of the mineshaft from a winch system pulled from bottom upward. In this new approach, within overlapped region viewed by the multi-channel lidar, rotation error was compensated for by comparing the similarity between the scan data at the same depth. The fabricated system was applied to scan 0-165 m depth of the mineshaft with 180 m depth. The reconstructed image was depicted in a 3D graph for interpretation.

• Economic and Environmental Geology
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• v.55 no.1
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• pp.53-61
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• 2022

The Gasado Au-Ag deposit is located within the south-western margin of the Hanam-Jindo basin. The geology of the Gasado is composed of the late Cretaceous volcaniclastic sedimentary rocks and acidic or intermediate igneous rocks. Within the deposit area, there are a number of hydrothermal quartz and calcite veins, formed by narrow open space filling along subparallel fractures in the late Cretaceous volcaniclastic sedimentary rock. Vein mineralization at the Gasado is characterized by several textural varieties such as chalcedony, drusy, comb, bladed, crustiform and colloform. The textures have been used as exploring indicators of the epithermal deposit. Mineral paragenesis can be divided into two stages (stage I, ore-bearing quartz veins; stage II, barren carbonate veins) considering major tectonic fracturing event. Stage I, at which the precipitation of Au-Ag bearing minerals occurred, is further divided into three substages (early, middle and late) with paragenetic time based on minor fractures and discernible mineral assemblages: early, marked by deposition of pyrite and pyrrhotite with minor chalcopyrite, sphalerite and electrum; middle, characterized by introduction of electrum and base-metal sulfides with minor argentite; late, marked by argentite and native silver. Au-Ag-bearing mineralization at the Gasado deposit occurred under the condition between initial high temperatures (≥290℃) and later lower temperatures (≤130℃). Changes in stage I vein mineralogy reflect decreasing temperature and fugacity of sulfur (≈10^-10.1 to ≤10^-18.5atm) by evolution of the Gasado hydrothermal system with increasing paragenetic time. The Gasado deposit may represents an epithermal gold-silver deposit which was formed near paleo-surface.

• Economic and Environmental Geology
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• v.56 no.4
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• pp.385-396
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• 2023

The Mesozoic Bansong Group, distributed along the NE-SW thrust fault zone of the Okcheon Fold Belt in the Danyang-Yeongwol-Jeongseon areas, contains important information on the two Mosozoic orogenic cycles in the Koran Peninsula, the Permian-Triassic Songrim Orogeny and the Jurassic Daebo Orogeny. This study aims to review previous studies on the stratigraphy, depositional period, and basin evolution of the Bansong Group and to suggest future research directions. The perspective on the implication of the Bansong Group in the context of the tectonic evolution of the Korean Peninsula is largely divided into two points of view. The traditional view assumes that it was deposited as a product of the post-collisional Songrim Orogeny and then subsequently deformed by the Daebo Orogeny. This interpretation is based on the stratigraphic, paleontologic, and structural geologic research carried out in the Danyang Coalfield area. On the other hand, recent research regards the Bansong Group as a product of syn-orogenic sedimentation during the Daebo Orogeny. This alternative view is based on the zircon U-Pb ages of pyroclastic rocks distributed in the Yeongwol area and their structural position. However, both models cannot comprehensively explain the paleontological and geochronological data derived from Bansong Group sediments. This suggests the need for a new basin evolution model integrated from multidisciplinary data obtained through sedimentology, structural geology, geochronology, petrology, and geochemistry studies.

• Environmental and Resource Economics Review
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• v.31 no.4
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• pp.645-668
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• 2022

Hydrogen energy is emerging as an important means of carbon neutrality in the various sectors including power, transportation, storage, and industrial processes. Fuel cell power plants are the fastest spreading in the hydrogen ecosystem and are one of the key power sources among means of implementing carbon neutrality in 2050. However, high volatility in system marginal price (SMP) and renewable energy certificate (REC) prices, which affect the profits of fuel cell power plants, delay the investment timing and deployment. This study applied the real option methodology to analyze how the dual uncertainties in both SMP and REC prices affect the investment trigger price level in the irreversible investment decision of fuel cell power plants. The analysis is summarized into the following three. First, under the current Renewable Portfolio Standard (RPS), dual price uncertainties passed on to plant owners has significantly increased the investment trigger price relative to one under the deterministic price case. Second, reducing the volatility of REC price by half of the current level caused a significant drop in investment trigger prices and its investment trigger price is similar to one caused by offering one additional REC multiplier. Third, investment trigger price based on gray hydrogen and green hydrogen were analyzed along with the existing byproduct hydrogen-based fuel cells, and in the case of gray hydrogen, economic feasibility were narrowed significantly with green hydrogen when carbon costs were applied. The results of this study suggest that the current RPS system works as an obstacle to the deployment of fuel cell power plants, and policy that provides more stable revenue to plants is needed to build a more cost-effective and stable hydrogen ecosystem.

• Journal of Environmental Impact Assessment
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• v.32 no.3
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• pp.157-165
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• 2023

In Korea, a major contaminant of farmland soils in the vicinity of abandoned mines is arsenic, for which the general soil reclamation method is contaminated soil stabilization and cover the stabilized soil with clean soil at a thickness of 40 cm. In a previous pot experiment study we confirmed the feasibility of a lower thickness (20 cm) of covering soil for such reclamation in abandoned coal mines, where arsenic contamination levels are generally lower than in metal mines. In this subsequent study a field experiment including rice plant cultivation in field test plots was conducted. For over 4 months, the transfer of arsenic from the contaminated soil to the unpolished rice grains was reduced by 44% when a clean soil covering with a thickness of 20 cm was applied. The maximum decrease (56%) was shown when the stabilization process was performed before the covering. These results reveal a lower thickness of clean soil covering has a high feasibility and it can increase cost-efficiency in the reclamation of an abandoned coal mine.