• Tunnel and Underground Space
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• v.22 no.6
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• pp.412-428
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• 2012

To achieve mine development, a large amount of data concerned with the geological structure and the ore body had to be investigated and collected through geological survey, drilling and geophysical explorations. In most previous cases, however, the data were usually analyzed two dimensionally and those results showed some limits because of their 2D presentation. Those 2D maps such as geological plane sections or longitudinal sections cause lots of difficulties in understanding the complex geological structure or the feature of ore body in a spatial way. In this study, research area was set on the abandoned Yangyang iron mine in Korea and the Sugaeng ore body within the mine was selected as the research target to design a mine haulage system for reopening. A 3D mine model of this area was tried to be constructed using a 3D modelling software, GEMS. An accurate 3D model including the ore body, the geological structure, the old underground mine drifts and the new mine drifts was constructed under the purpose of reopening of the abandoned iron mine. Especially, mine design for trackless haulage system was conducted. New inclines and drifts were planned and modelled 3 dimensionally considering the utilization of old drifts and shaft. In addition to the 3D modelling, geostatistical technique was adopted to generate a spatial distribution of the ore grade and the rock physical properties. 3D model would be able to contribute in solving problems such as evaluating ore reserves, planning the mine development and additional explorations and changing the development plans, etc.

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

• Tunnel and Underground Space
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• v.24 no.2
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• pp.111-119
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• 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
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• v.26 no.2
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• pp.87-99
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• 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
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• v.26 no.4
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• pp.253-265
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• 2016

In this study, travel time data collection of mine equipments was conducted in an underground mine using a reverse Radio Frequency IDentification (RFID) system. In the reverse RFID system, RFID readers and antennas are mounted on mine equipments, and RFID tags are attached to the underground mine gallery. Indoor experiments were performed to analyze how RFID reader transmission power levels affect tag readable area and tag recognition rates. The results showed that travel time measurement become precise when the reader transmission power was reduced, however tag recognition rates were reduced. The field experiments indicated that setting the reader transmission power to 28 dBm maintained the tag recognition rate while minimizing the tracking location error. In addition, the results revealed that the reverse RFID system can be used successfully in an underground mine to collect the travel time data of haulage trucks.

• Tunnel and Underground Space
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• v.28 no.6
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• pp.555-568
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• 2018

To perform efficient and safe haulage operations in mines, the condition of unsurfaced roads where dump trucks are moving should be regularly investigated, and systematic maintenance should be carried out according to the results. In this study, we developed a smartphone application that can be used to periodically investigate the unsurfaced road conditions in mines. Using the developed application, necessary data can be easily collected on site to evaluate the condition of unsurfaced roads according to the Unsurfaced Road Condition Index (URCI) evaluation system presented by the US Army Corps of Engineers. The smartphone application was tested at several sections of unsurfaced road in the Ilkwang mine, Busan, Korea. The results showed that the field investigation about 7 factors considered in the URCI evaluation system can be conducted through the user interface screen, and the URCI value can be calculated in the field to evaluate the condition of unsurfaced road. The smartphone application developed in this study can be useful for surveying and evaluating the unsurfaced road conditions at the mine site.

• Geomechanics and Engineering
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• v.15 no.6
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• pp.1173-1182
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• 2018

The coal wall, gob-side backfill, and gangues in goaf, constitute the support system for Gob-side entry retaining (GER) in coal mines. Reasonably allocating and utilizing their bearing capacities are key scientific and technical issues for the safety and economic benefits of the GER technology. At first, a mechanical model of GER was established and a governing equation for coordinated bearing of the coal-backfill-gangue support system was derived to reveal the coordinated bearing mechanism. Then, considering the bearing characteristics of the coal wall, gob-side backfill and gangues in goaf, their quantitative design methods were proposed, respectively. Next, taking the No. 2201 haulage roadway serving the No. 7 coal seam in Jiangjiawan Mine, China, as an example, the design calculations showed that the strains of both the coal wall and gob-side backfill were larger than their allowable strains and the rotational angle of the lateral main roof was larger than its allowable rotational angle. Finally, flexible-rigid composite supporting technology and roof cutting technology were designed and used. In situ investigations showed that the deformation and failure of surrounding rocks were well controlled and both the coal wall and gob-side backfill remained stable. Taking the coal wall, gob-side backfill and gangues in goaf as a whole system, this research takes full consideration of their bearing properties and provides a quantitative basis for design of the support system.