• Tunnel and Underground Space
• /
• v.25 no.4
• /
• pp.373-382
• /
• 2015

This study presents a method to calculate carbon dioxide emissions of diesel vehicles operated in an underground mine using Geographic Information Systems (GIS). An underground limestone mine in Korea was selected as the study area. A GIS database was constructed to represent the haulage roads as a 3D vector network. The speed of dump trucks at each haulage road was investigated to determine the carbon dioxide emission factor. The amount of carbon dioxide emissions related to the truck's haulage work could be calculated by considering the carbon dioxide emission factor at each haulage road and the haulage distance determined by GIS-based optimal route analysis. Because diesel vehicles are widely utilized in the mining industry, the method proposed in this study can be used and further improved to calculate the amount of carbon dioxide emissions in mining sites.

• Tunnel and Underground Space
• /
• v.27 no.1
• /
• pp.12-25
• /
• 2017

In local underground mines heavily depending on the natural ventilation, ducted fan auxiliary ventilation system is strongly recommended instead of the total mine ventilation system requiring large capital and operating costs. Optimizing the installation of ducted fans in series in long large-opening mines is required to assure the economy and efficiency of the ventilation system. The two most critical design parameters for optimization are the wall separation distance and gap length between adjoining ducts. This study aims at deriving the optimal values for those two parameters concerning the economic and environmental aspects through the extensive CFD analysis, which minimizes pressure loss, leakage and entrainment of the contaminated air in the gap space. The ranges of the wall separation distance and gap length for study are selected by taking into consideration the existing recommendations and guidelines. The ultimate goal is to optimize the auxiliary ventilation system using ducted fans in series to provide a reliable and efficient solution to maintain clean and safe workplace environment in local long underground mines.

• Journal of Conservation Science
• /
• v.32 no.4
• /
• pp.471-490
• /
• 2016

This study investigated provenance of raw materials and making technique of lime-based materials used in the tomb barriers of the Yesan Mokri tombs from Joseon dynasty on the basis of analysis to material characteristics and physical properties. In the barrier materials, dry density and porosity are the highest value ($1.82g/cm^3$) and the lowest value (25.20%) in the south wall of No. 1 tomb, respectively. Dry density and porosity are inversely proportional in all barrier materials, but unconfined compressive strength, which is the highest value of $182.36kg/cm^2$ in the No. 2 tomb, does not show an interrelation with porosity and density. Mineral components in the lime-soil mixtures of the tomb barrier are mainly quartz, feldspar, mica and calcite about 200 to $600{\mu}m$ size with yellowish brown matrix. Hydrotalcite and portlandite are detected in the lime mixture, and kaolinite in the soils. The lime materials of the tomb barrier occurred in large quantities weight loss and variable endothermic peaks caused by decarbonization reaction of $CaCO_3$ in the range from 600 to $800^{\circ}C$ in thermal analysis. Making temperature of lime for the tomb barrier is presumed approximately about $800^{\circ}C$ based on the occurrences, compositions and thermal analysis. The tomb barriers are revealed to very wide composition ranges of major elements and loss-on-ignition (22.5 to 33.6 wt.%) owing to mixture of the three materials (lime, sand and clay). It is interpreted that low quality construction technique was applied as the limes are very heterogeneous mixture with aggregates, and curing of the lime was poorly processed in the tomb barriers. Possible limestone sources are distributed in many areas around the Mokri site where limestone conformation and quarries for commercial production are found within Yesan and Hongseong areas. Therefore, we estimated that raw materials were possibly supplied from the local mines near the Mokri site.

• Tunnel and Underground Space
• /
• v.27 no.6
• /
• pp.406-421
• /
• 2017

This study describes a precise numerical analysis process by adopting the real image of mine openings obtained by LIDAR, which can produce a point cloud data by measuring the target surface numerically. Research area is a section of underground limestone mine which is used hybrid room-and-pillar method for improving the production rate. From the application of LIDAR to this section several results were deduced, that is, the central axis of upper and lower vertical safety pillars is distorted to the direction of NW and the section area of lower vertical safety pillar is $34m^2$ smaller than the designed area of $100m^2$. The results of precise measurement in geometrical shape of mine openings and precise simulation in numerical analysis confirms that LIDAR techniques can be suggested as a valuable tool for stability analysis in underground mine by configuring the mine opening shape.

• Tunnel and Underground Space
• /
• v.15 no.5 s.58
• /
• pp.338-343
• /
• 2005

This study analysed response spectrum using the observed ground motion from the mine blasting and, then compared the results to the seismic design response spectra applied domestic nuclear power plants. The results showed that the resultant response spectra above 20 Hz revealed higher values than the design response spectra and those below 20 Hz revealed much lower values. These facts suggest that the analysis of response spectrum should be applied to the analysis of impacts to frequency dependent structures in addition to the analysis of peak values of ground motions.

• Journal of Environmental Impact Assessment
• /
• v.23 no.1
• /
• pp.1-9
• /
• 2014

This study, focusing on the area expansion of limestone mines, identifies the problems of Environmental Impact Assessment(EIA) and what impact the current problems exert on another mines developing process. The legal relations analysis reveals that the Management of Mountainous Districts Act and other related laws effect on EIA process, especially the case of area expansion of limestone mines excluded from EIA. However, these problems can create mismatch with the policy goal of EIA system and have a negative impact on the environment in the future. A series of indepth interviews with managers in related agencies found that those agencies have been unaware of the seriousness of the problem. Without any strategy, negative result made by development activities would get more serious and sustainable development may not be possible at all. In order to solve these problems, government should modify the current interdependent legal provision and create the incentive structure to participate actively related agency in the EIA system.

• Tunnel and Underground Space
• /
• v.24 no.6
• /
• pp.430-439
• /
• 2014

This study developed a simulation program for truck-loader haulage systems in an underground mine. A limestone underground mine in Korea was selected as a study area and investigated to design the simulation algorithm for truck-loader haulage systems. GPSS/H simulation language was utilized to develop the simulation program. Simulations were conducted to analyze the optimal number of haulage trucks dispatched in the 540 ML loading point by using the developed program. The simulation results showed that 8 trucks can maximize the daily production (2,076 ton). The real production (1,850 ton/day) of limestone ores was very similar to the simulated one (1,850.35 ton/day) when considers 7 trucks dispatched in the 540 ML loading point. In addition, average waiting time at loader were similar (waiting time by time study : 1.39 min, simulated waiting time : 1.35 min).

• Tunnel and Underground Space
• /
• v.26 no.2
• /
• pp.87-99
• /
• 2016

We developed a Windows-based program for discrete event simulation of truck-loader haulage systems in an underground mine. The Daesung MDI limestone mine located in Samcheok City, Gangwon Province, Korea was selected as the study area to design the program. The developed program is composed of the graphic user interface (GUI) and simulation engine implemented by Visual Basic.NET 2012 and the GPSS/H simulation language, respectively. When a user sets up input parameters for the discrete event simulation through GUI, the program activates the simulation engine, and then simulation results are displayed on GUI. This paper describes the details of the program development as well as its applications to the study area to determine the optimal number of trucks dispatched at each loading point under different operating conditions.

• Tunnel and Underground Space
• /
• v.24 no.2
• /
• pp.111-119
• /
• 2014

This study developed a Windows-based simulation program for selecting equipments in open-pit shovel-truck haulage systems. Visual Basic.NET 2012 was used to develop the graphic user interface (GUI) and the GPSS/H simulation language was utilized to implement the simulation engine of program. When users establish simulation parameters through the GUI, the program calls the simulation engine to perform the simulations repeatedly. Then, it finds the optimal fleet of equipments required for operating the open-pit shovel-truck haulage systems efficiently. Application of the program to the Ssangyong open-pit limestone mine, Gangwon-do, Korea, showed that the daily average profit of shovel-truck haulage operation can be maximized (i.e. 88,552 USD) under following conditions: (a) 4 trucks are dispatched into each loading point and (b) a crusher with capacity of 1,500tph is utilized.

• Tunnel and Underground Space
• /
• v.24 no.1
• /
• pp.1-10
• /
• 2014

This paper presents a case study that performed simulations on shovel-truck haulage systems in an open-pit mine by considering truck's breakdown and crusher's capacity. The SSangyoung limestone open-pit mine in Korea was selected as a study area and investigated to design the simulation algorithms. The GPSS/H simulation language is used to implement the simulation algorithms as a console application(simulator). The values of input parameters for simulator were measured by field investigation in the study area. The simulation results showed that 7 trucks can maximize the daily profit of haulage operations(i.e., 73,775 USD) when considers the frequency of trucks' breakdown as 1/40 $hour^{-1}$. In addition, the crusher capacity of 1300 tph is required to improve the efficiency of shovel-truck haulage systems in the study area.