• Journal of the Korean Ceramic Society
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• v.45 no.7
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• pp.395-400
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• 2008

This paper indicates the investigation about the development of ET (Environmental Technology) industrial geopolymeric materials from mixture silica mine waste, coal fly ash and alkali activator solution (sodium silicate) by the geopolymer technique at ambient temperature. The results showed that higher compressive strength of geopolymeric mortar increased with a reduce of L/S ratio and increased along with an increase of coal fly ash content. The compressive strengths of geopolymer mortar on low silica of C Silica Mine and K Silica Mine are 18.7 MPa, 20.4 MPa, respectively. Compressive strength of geopolymeric mortar depends on L/S ratio and coal fly ash content added.. Additionally, scanning electron microscope (SEM) techniques are used to characterize the microstructure of the geopolymeric mortars. SEM observation shows that it is possible to have amorphous aluminosilicate gel within mortar. XRD patterns indicate the fact that geopolymeric mortar is composed of amorphous aluminosilicate phase, calcite and quartz.

• Resources Recycling
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• v.19 no.6
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• pp.77-85
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• 2010

This study was carried out to develop a process flow sheet for recovering valuables (gold and high purity silica) from the gold mine tailings containing 1.7 g/ton of gold and 79.48 wt.% $SiO_2$. Float-sink tests using heavy liquids was conducted to explore the possibility of recovering gold by gravity separation. Hydrocyclone, froth flotation, and triboelectrostatic separatoin tests were conducted to recover high purity silica from the gold mine tailings. The results of float-sink tests showed that particles containing 5.58 g/ton of gold could be obtained at 2.72 specific gravity, but with very low yields around 3%. Meanwhile, all tests with hydrocyclone, froth flotation, and triboelectrostatic separation showed that high purity silica with $SiO_2$ content over 90% could be obtained. The purity could be improved further up to about 94% by employing several recleaning steps in the froth flotation and triboelectrostatic process.

• Journal of Korean Society on Water Environment
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• v.26 no.3
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• pp.413-419
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• 2010

A silica mine monitoring was conducted from March to December in 2008 to measure rainfall, runoff amounts and pollution loads. A total of 13 rainfall-runoff events were measured and analyzed with respect to runoff ratio, pollutant concentration and load, and initial flush. Over rainfall-runoff events, 95% confidence range of SS concentration was 942.5~2,056.2 mg/L. Other measured water quality indices also showed relatively large variation. This wide concentration variation was thought to be caused by the bare working ground of the mine that was used to store, process and transport the mined silica. Total pollution load of the 13 rainfall-runoff events was SS 17,901 kg/ha, $COD_{Cr}$ 160.9 kg/ha, $COD_{Mn}$ 111.24 kg/ha, BOD 79.6 kg/ha, T-N 13.8 kg/ha, T-P 3.5 kg/ha, and TOC 39.3 kg/ha. Initial flush was not well observed except SS. Very high SS concentration and load was occurred when rainfall was large. Therefore, it was recommended to manage the bare ground not to discharge excessive pollutants during wet days by covering the ground or constructing runoff treatment systems such as a sediment basin.

• Explosives and Blasting
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• v.30 no.1
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• pp.52-59
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• 2012

Fragmentation is one factor to affect productivity and economic efficiency of mine. Authors investigate the blasting pattern and improve it step by step while observing the fragmentation results. Final pattern was suggested and the fragmentation improved 24 % compared to traditional pattern, with 50 % is passing rate.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.1
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• pp.66-73
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• 2019

Approximately 80% of the mines are vacated or abandoned mines and are mostly left without suitable environmental treatment facilities. In the area around the abandoned mine site, problems such as drainage of acidic city drainage and leakage of leachate occur, and ground subsidence caused by this can cause a safety accident due to sink hole occurrence. In this study, flow, compressive strength, water uptake, pore and hydration characteristics were investigated to investigate the basic properties of liner and cover material based on the replacement ratio of nano silica and silica fume in the existing blast - furnace slag fine powder. As a result, as the substitution ratio of nano silica and silica fume increased, the flow and compressive strength of nano silica specimens increased and the absorption rate decreased. In the case of pore characteristics, the amount of pores decreased as the substitution ratio of nano silica and silica fume increased. Especially, the capillary porosity of 10-1,000 nm diameter decreased. Ray diffraction analysis and SEM measurement showed that the peak positions of the hydration products were almost the same when compared with the 5% alternative test samples of Plain and silica fume.

• Journal of Industrial Technology
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• v.30 no.A
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• pp.17-23
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• 2010

Recently, a large number of open-pit mines are planning to change their mining method to underground types because the environmental concerns and legal regulations are increased with a rise in the standard of living. The K silica mine, which is one of them and located in Kyunggi province, is planning the establishment of a vertical shaft which will be used for ore-pass channel in their new glory hole mining method. This vertical shaft will be designed to join with a horizontal gangway excavated from the ground level. In this new mining system, the excavated ore particles will be stored inside a shaft and transported out with a help of a conveyor belt. Therefore the hang-up of ore particles in a shaft, the control of gate at the bottom of a shaft, the installation of dog-leg at the gate should be investigated identically. In this study, the PFC-2D code which is one of the discrete element numerical methods has been applied to simulate the particle flow mechanism in a shaft, and the optimum mine design has been proposed to maximize the productivity and to minimize the system damage.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.1042-1046
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• 2009

강원도 홍천군 북방면 능평리에 위치한 규사광산을 2008년 3월부터 12월까지 발생한 강우사상에 대하여 모니터링을 실시하였다. 모니터링 지점은 채광작업과 가공작업이 이루어지는 계곡의 하류로 평시 $500m^2$/day의 유량이 흐르는 작은 소하천이다. 관측된 13회의 총 강우량은 712.6 mm가 발생하였다. 강우강도는 0.5 ${\sim}$ 4.7 mm/hr, 선행무강우일수는 1.2 ${\sim}$ 9.8일로 나타났다. 유출률은 28.0 $^{\sim}$ 98.0 %로 나타났으며, 유출율 98.0 %는 168.0 mm의 많은 양의 강우가 발생한 7월 24일부터 25일까지의 강우사상에서 발생하였다. 채석과 가공작업등의 영향으로 인하여 강우시 다른 오염 물질보다 SS 농도와 EMC가 매우 높고, 범위가 가장 큰 것으로 나타났다. 또한 SS는 강우량과 건기일수에 민감한 영향이 있는 것으로 나타났다. 따라서 규사광산지역은 다른 오염 물질보다 SS를 저감 시킬 수 있는 비점오염저감시설이 필요할 것으로 사료된다. 기상조건에 따른 오염부하와 EMC의 정확한 산정하기 위해서는 장기간의 모니터링을 통한 많은 자료의 수집이 동반되어야 할 필요가 있다. 본 연구에서 조사된 자료와 분석된 결과는 토지이용별 비점오염부하의 산정과 저감기술의 개발에 활용할 수 있으며, 수질오염총량제의 신뢰성을 향상시킬 것으로 판단된다.

• Resources Recycling
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• v.8 no.3
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• pp.37-42
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• 1999

Ths sludy was canied out to recover gold and sllics from abandoned gold mine talings with about 4.5 ghonAu and 84.88 wt% SOz. Tl~bee nef~cialiop~ro~c esses including crushing, screening, magnelic and gravity (humprey sp~rals,h aking table) separation \ulcornervex employed. Results were Feasible to rccovn h e gold concentrates (307.1 gltoilon .4u . 0.60 wr%, 97.7 giton Au : 0.27 wl%, 15.3 &/ton Au . 5.23 wt%, 21.2 g/ton Au : 2.42 wl%) and silica (96.40 wi% SiO\ulcorner yield 60 65 ~ 1 % )

• Economic and Environmental Geology
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• v.39 no.6 s.181
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• pp.699-710
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• 2006

Batch scale experiments to investigate the efficiency of the solidification process for metal mine tailing treatment were performed. Portland and MSG (micro silica pouting) cements were used as solidifier and three kinds of mine tailings (located at Gishi, Daeryang, and Aujeon mine) were mixed with cements to paste solidified matrices. Single axis com-pressible strengths of solidified matrices were measured and their heavy metal extraction ratios were calculated to investigate the solidification efficiency of solidified matrices created in experiments. Solidified matrices ($5cm{\times}5cm{\times}5cm$) were molded from the paste of tailing and cements at various conditions such as different tailing/cement ratio, cement/water ratio, and different cement or tailing types. Compressible strengths of solidified matrices after 7, 14, and 28 day cementation were measured and their strengths ranged from 1 to $2kgf/mm^2$, which were higher than Korean limit of compressible strength for the inside wall of the isolated landfill facility ($0.21kgf/mm^2$). Heavy metal extractions from intact tailings and powdered matrices by using the weak acidic solution were performed. As concentration of extraction solution for the powdered solidified matrix (Portland cement + Gishi tailing at 1:1 w.t. ratio) decreased down to 9.7 mg/L, which was one fifth of As extraction concentration for intact Gishi tailings. Pb extraction concentration of the solidified matrix also decreased to lower than one fourth of intact tailing extraction concentration. Heavy metal extraction batch experiments by using various pH conditions of solution were also performed to investigate the solidification efficiency reducing heavy metal extraction rate from the solidified matrix. With pH 1 and 13 of solution, Zn and Pb concentration of solution were over the groundwater tolerance limit, but at pH $1{\sim}13$ of solution, heavy metal concentrations dramatically decreased and were lower than the groundwater tolerance limit. While the solidified matrix was immerged Into very acidic or basic solution (pH 1 and 13), pH of solution changed to $9{\sim}10$ because of the buffering effect of the matrix. It was suggested that the continuous extraction of heavy metals from the solidified matrix is limited even in the extremely high or low pH of contact water. Results of experiments suggested that the solidification process by using Portland and MSG cements has a great possibility to treat heavy metal contaminated mine tailing.

• Geomechanics and Engineering
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• v.20 no.1
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• pp.67-73
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• 2020

With the increasing number of underground projects, the problem of rock-water coupling catastrophe has increasingly become the focus of safety. Grouting reinforcement is gradually applied in subway, tunnel, bridge reinforcement, coal mine floor and other construction projects. At present, cement-based grouting materials are easy to shrink and have low strength after solidification. In order to overcome the special problems of high water pressure and high in-situ stress in deep part and improve the reinforcement effect. In view of the mining conditions of deep surrounding rock, a new type of cement-based reinforcement material was developed. We analyses the principle and main indexes of floor strengthening, and tests and optimizes the indexes and proportions of the two materials through laboratory tests. Then, observes and compares the microstructures of the optimized floor strengthening materials with those of the traditional strengthening materials through scanning electron microscopy. The test results show that 42.5 Portland cement-based grouting reinforcement material has the advantages of slight expansion, anti-dry-shrinkage, high compressive strength and high density when the water-cement ratio is 0.4, the content of bentonite is 4%, and the content of Nano Silica is 2.5%. The reinforcement effect is better than other traditional grouting reinforcement materials.