• Tunnel and Underground Space
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• v.29 no.1
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• pp.30-37
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• 2019

Some leading countries in mining have a very quantitative guideline for underground mine opening design which is useful to minimize mine hazards such as rockfall and collapse. Those hazards sometimes can cause a huge damage on human life and property in the mines. Construction guidelines of underground mines in Korea consist of qualitative and general expressions although the workers' safety rules and guides are well provided. Recently, mining operations in Korea are going underground due to the environmental regulations and resource depletion at shallow depth, and therefore there is a growing demand on a specialized and systematic guideline for mine opening design securing the underground stability. In this paper, current status of mining industry, research trends, and mining guidelines in Korea and overseas have been reviewed to give an insight into developing a new Korean guideline for underground mine design.

• Journal of Korean Tunnelling and Underground Space Association
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• v.4 no.2
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• pp.123-133
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• 2002

In the construction of the road tunnel in mine area, old mine gangways can cause the instability of the tunnel. In this case study, the field investigation is carried out to figure out the location of old gangways adjacent to the tunnel, and their influence on the tunnel stability is estimated according to the location pattern and rock condition by FLAC analysis. The grouting reinforcement of tunnel crown region and old gangway is suggested and its role on assurance of the tunnel stability is also verified. It can be said from this study that the effect of the old gangway on the stability of tunnel varies with the dimension of gangway, distance from the tunnel, rock condition and groundwater, and therefore these paramerter should be compositively considered in the assessment of the tunnel stability.

• Tunnel and Underground Space
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• v.27 no.2
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• pp.69-76
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• 2017

Physical models of underground mines are very useful to the design of mine openings and the management of work progress of mining companies as well as to consulting. Even though 3D image realization techniques for mine openings have already been developed by various companies the physical models are still widely used because they can provide better understanding without sophisticated equipments for the most of people. Conventional materials for the physical models are paper and acryl which demand a lot of time and labor to make the model even with low precision and high cost. In this research, 3D printing technique is adopted to develop the physical model with relatively short time, low cost, and proper degree of precision. Finally the computer software "UMine2STL" was developed and verified by comparing the printed product with its design.

• Tunnel and Underground Space
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• v.19 no.6
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• pp.517-525
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• 2009

Stereophotogrammetry is used to extract spatial information of an interested object by constructing a stereo-image from two or more photos. In this study, the stereophotogrammetry was adopted for a rock joint survey in mine tunnels. The orientations of discontinuities were measured from two mine tunnels with a clinocompass. To evaluate the effect of photographing light level on the stereophotogrammetry analysis, the light intensity was changed within a predefined range for every photograph. Those photographs were analyzed by using a commercial code for stereophotogrammetry - ShapeMetriX 3D, and the results from the analysis were compared with the manual measurement using a clinocompass.

• Explosives and Blasting
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• v.35 no.3
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• pp.1-8
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• 2017

In this paper, parametric studies are conducted to evaluate the contribute effect of multi layered room and pillar mine structures by underground accidental explosions. Influence of PPV(Peak Particle Velocity) obtained from large explosion at a multi layered room and pillar mine was numerically simulated by using AUTODYN. Parameters for contribution rate Analysis was analyzed by the robust design method. Orthogonal array is $L_9(3^4)$, which was adopted in this study, the parameters were pillar height, pillar width, mine span and sill pillar of 3 levels. Results of analysis showed that bottom mine of vertical direction from explosion point are most affected by pillar height, followed by sill pillar thickness, mine span and pillar width. Parameters affecting adjacent mine of horizontal direction from explosion are in the order of pillar width, mine span, pillar height and sill pillar thickness.

• Tunnel and Underground Space
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• v.24 no.3
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• pp.212-223
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• 2014

In this study, the stability analyses for metal mine roadways at a great depth were performed. In-situ stress measurements using hydrofracturing, numerous laboratory tests for rock cores and GSI & RMR classifications were conducted in order to find the physical properties of both intact rock and in-situ rock mass distributed in the studied metal mine. Through the scenario analysis and probabilistic assessment on the results of rock mass classification, the in-situ ground conditions of mine roadways were divided into the best, the average and the worst cases, respectively. The roadway stabilities corresponding to the respective conditions were assessed by way of the elasto-plastic analysis. In addition, the appropriate roadway shapes and the support patterns were examined through the numerical analyses considering the blast damaged zone around roadway. It was finally shown to be necessary to reduce the radius of roadway roof curvature and/or to install the crown reinforcement in order to enhance the stability of studied mine roadways.

• Tunnel and Underground Space
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• v.28 no.4
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• pp.358-371
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• 2018

The stability of openings in the underground mine is major concern in the operation of mines that must ensure productivity and safety. Among many rock conditions affecting cavities stability, the width and height of the opening is an important design factor. In this paper, we consider to determine the maximum unsupported span of a opening in a limestone mine by using the Q system among several rock classification schemes. In order to determine the span of the unsupported opening in the limestone mine, rock mass classifications were carried out at over 200 sites in the underground limestone mines. The relationships by using the Q system and the stability graph proposed by Mathews to determine the maximum span of the unsupported opening were derived and compared. We propose a new classification method that combines GSI and RMR rock classification systems to make it easy to use in a field.

• Tunnel and Underground Space
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• v.28 no.2
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• pp.125-141
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• 2018

For a long-term mine development plan, the determination and design of mine tunnel size are very important because it is the basis of plans for equipment, transportation and operation. The ${\bigcirc}{\bigcirc}$ mine has had a difficulty in changing the mining plan due to the design of the tunnels with an emphasis on productivity improvement, and much effort was needed to maintain the mine tunnel. In this study, we designed the mine tunnel with optimized tunnel span considering the mechanical properties of rockmass and established the support plan. To do this, the estimation of the mechanical parameters(Swelling pressure, deformation coefficient and earth coefficient), field investigations and various analyses were carried out. As a result, it was necessary to consider the downsizing of the tunnel section in order to maintain the tunnel stability and dimension by using the roof bolt and analyzed that various functional constructions of the support material and method would be required to maintain the current tunnel size.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.11a
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• pp.213-234
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• 2002

우리 나라는 70년대까지 광업은 부흥하였으나, 그 이후 급속히 위축되면서 80년대 이후 거의 대부분 광산들이 폐광 또는 휴광된 실정이다. 그 결과 현재 전국 각지에 다수의 폐갱도가 존재하게 되었으며, 이제는 지반침하 및 각종 침출수의 원인자로 간주될 정도이다. 최근 지자체에서는 이런 폐갱도를 지역 자원으로서 가치를 인정하고 지역 활성화를 위해 재 이용하려는 움직임이 보이고 있는데, 구체적으로는 관광시설, 연구시설, 농업생산시설, 저장시설, 폐기물처리시설 등이다. 일본은 폐광된 금속광산 재활용을 위해 입지여건과 주변지역, 입갱 가능성 등 기초조사를 하였다. 조사결과 폐갱도의 문제점으로 입갱이 가능한 광산이 적다는 점을 들 수 있다. 대부분의 광산은 갱구가 함몰되었거나, 갱내에 지하수가 차 있어 접근이 불가능한 경우가 대부분이다. 비교적 양호한 암반 경우는 서브 레벨 스토핑, 잔주, 주방식 등의 채굴법에 의해 대규모 공동이 잔존하고 있는 경우도 있지만 그리 많지 않았다. 폐광된 광산 재활용 여건은 우리 나라와 일본이 대동소이 경우로 현실적으로 활용이 가능한 폐광은 많지 않으며 활용코자 할 때에는 기존갱도를 활용하면서 암반이 견고한 곳에 새로운 갱도를 설치하여야 한다. 그러나 몇몇 곳에서는 매우 유용하게 잘 활용되고 있는 곳도 있고, 연구 검토하면 충분한 활용성이 있다고 생각되는 곳도 있다. 그러므로 현재의 상황을 보고 판단할 것이 아니라, 활용기술과 접목해서 활용성을 검토함으로써 불용 자산의 유용화 방안이 검토되어야 할 것이다. 현재 가행중인 광산은 입지여건 및 암반이 양호하고, 대형갱도를 굴착하는 석회석광산 등을 선택하여 폐광 후 활용이 가능토록 채광기술 발전시켜 나가야 하며, 인간 중심적인 시설 또는 산물 중심적인 시설로 구분하여 폐광 후 복구비용을 우선 지원하는 방식 등을 통하여 시추, 탐광굴진, 현대화, 수갱굴착, 자금융자 등을 지원하는 우리 공사와 산업자원부가 지자체, 산림청, 건교부, 농림부 등과 연계하여 종합적인 지원육성책을 마련하여야 할 것이다. 결과적으로, 지방자치단체 등에서 관심을 갖고 있는 저장시설, 폐기물처리시설, 관광시설, 농업생산시설, 연구시설 등을 중심으로 ＆apos;광산 채굴적을 미래에 어떻게 활용한 것인가＆apos;를 선진외국 사례를 벤치마킹하고, 연구ㆍ검토하여 친환경적인 광산개발이 되도록 기본적인 방향과 개념을 갖도록 하여 관련 정책을 계획적이고, 체계적으로 수립 일관성 있게 추진해 나가야 할 것이다.

• Tunnel and Underground Space
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• v.25 no.6
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• pp.543-555
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• 2015

At present, local limestone mines with large opening employ auxiliary fans for workplace ventilation which have been used in coal mines with much smaller airways. Considering the low static pressure loss in the large-opening mines, high pressure auxiliary fans face serious economical limitations mainly due to their excessive capacity. The optimal fan selected for the ventilation in large-opening working places should supply air quantity enough for maintaining safe environment and keep its operating cost as low as possible. This study focuses on the development of a low pressure auxiliary fan designed to have smaller range of the static head but to have more potential for higher ventilation and energy efficiency. The flow characteristics of high and low pressure auxiliary fans were theoretical as well as experimentally investigated to assess the ventilation efficiency in term of environmental and economical aspects. Moreover, the low pressure fan was tested in two limestone mine sites with small and large cross-sectional areas for evaluating its ventilation efficiency. Results from this study can be applied to improve the economy and efficiency of auxiliary fan for ensuring better air quality and work environment management.