• Explosives and Blasting
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• v.32 no.1
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• pp.10-17
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• 2014

In this study, the information achieved from the visit to Kazakhmys mine in Kazakhstan was introduced. An optimal blasting pattern designed for the mine with the application of Korean blast technology was suggested. As a result, it was found that the blast design can reduce the consumption of explosives and the number of drill holes. The blast design can reduce the overall production cost in the mine.

• Explosives and Blasting
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• v.34 no.2
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• pp.10-17
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• 2016

Drilling operation for blasting is an important factor to determine blast effect. Drilling errors that arise from performing drilling for blasting purposes can reduce blasting effect causing residual holes, overbreak, and heterogeneous fragmentation, etc. Automatic drilling system was induced for precise drilling. As a result, drilling error caused by spaces between holes and burden was minor at 0~2.6% and accordingly, blasting effect was improved with over 90% drilling rate, the ratio of overbreak amount to total drilling amount at 4.3%, proportion of fragmentation rock under 50cm at 89~95% and so from this analyses, it was estimated to reduce the total cycle times related to blasting process.

• Tunnel and Underground Space
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• v.16 no.2 s.61
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• pp.156-165
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• 2006

Already, vari-stem, gas-bag, power deck, air ball etc. are used by various blasting methods to take the advantage of air decking technology in abroad. Air tube product has been used continuously in domestic and air ball product was made recently. In the case study, we analyzed about the application and the effect or air deck blasting method in domestic blasting area. As results or this case study, it was shown that blasting vibration was decreased about $21{\sim}41%$ and quantities or explosives was decreased about $17{\sim}30%$. Also, in the case of using air deck blasting method, fragmentation was shown to be smaller than common blasting method.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.4
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• pp.458-465
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• 2017

The purpose of the present study was to examine the method of physically processing oyster shells for use as raw material(aggregate) through experimentation. The results of the experiment found that the adequate particle size of the pulverized oyster shells should be smaller than 10mm due to their shape. Also, after considering various particle size distributions and residual rates by particle size, the study found the cutter mill to be the most suitable tool for pulverizing oyster shells. The use of a cutter mill resulted in recovery rates of 97.3%, 98.2%, and 98.9% for inner screens of 8mm, 12mm, and 20mm respectively, revealing how the increase of screen size results in slightly higher recovery rates. The experiment involving the difference between the inner screen of the cutter mill and the speed of the inverter shows that a smaller screen size and a faster inverter speed result in a lower fineness modulus, while a rise in inverter speed for an identical screen made possible the material recovery of a much lower range of particle sizes.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.961-965
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• 2000

This study aims to predict the particle size of blasted rock. For this purpose, Predicted particle sizes were compared with the measured particle sizes at the rock blasting sites, where various blasting patterns which controls the bench height, depth of blasted hole, burden, spacing etc were tested. the difference of mean fragment size between measured and predicted values was 0.11m.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.04a
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• pp.261-264
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• 2000

악취가스제거용으로 흔히 파쇄상 활성탄소를 사용하고 있는데 조립상 침착 활성탄소를 사용하면 경도가 높고 입도가 균일하여 흡착탑 내에서 일정한 가스 유속분포를 얻을 수 있고 Life Time을 연장할 수 있기 때문에 여러 장점이 있다. 일반 활성탄소의 표면은 비극성이며 흡착력이 본질적으로 단순히 반델발스 힘에 의한 물리흡착이기 때문에 황화수소나 $NH_3$ 등 비점이 낮은 성분에 대해서는 충분한 흡착성을 갖지 못한다. (중략)

• Resources Recycling
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• v.6 no.3
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• pp.3-8
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• 1997

The EA.F. sleelmaking slag (slag that follow) of a cnmvany 1 Co.. containzd a simple substance of a metal, wustlte (FeO), magnetite (Fe,O,), gehlenite (CaAl,SiO,), monlicellite (CaMgSiO,), dc. To recovere a metal (Fe grade . t95%) in the slag, it is desirable that the particles of a metal are isolated from thc slag and madc for a liberated subslance. Then, the liberaled melal is easlly recoveled by a magnetic separation. If thc rcclarnalcd slag, the sizc of which ranges under 40 nun, have a mulli-stage crushing, the most of a metal in thc slag is simply isolaled as a liberated subslance. If the mad, lhat is a liberated subslance and a sphere, is recovered by a magnetic field intensity. the minimum intensity, at which a metal is attracted, is approximately IOOG and did no1 dcpcnd on the particle size of a metad in the same particles. TIe recovered material. that contdined a iron (Fe) over 95% is a metal which is crushed slag by l00G in the multi-stage. If the magnetic field intcns~ty increase, the recovery mcrcasc, but the concentration grade decrease Bewusc thc concentration eams more and more impurities, iron oxide and the coml~ound of alkali earth element. 'll~ercforc If the rccla~nated slag have the multi-stage crushing, the metal is almostly recovered in the crushed slag by lO0G on each particles. If the slag, used as a rcclamatian lhat is a amount of 350,000 tan from I Co., was undcr the multistage crushing and then separaled by 100gauss, it is possible to recova a metal approximately 2.500 Ion, lhat is 0.73% of n ~eclamated slag. in 304.7 mm particles and to recover 4.200 tan in 0.3-1.7 mm particles , that is 1.2% nf a rcclamated slag, in a year. Therefore, ihe told recoverable meld is 6,700 ton, that is 19% of a reclmated slag, in a year, too.

• Journal of the Korea Organic Resources Recycling Association
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• v.18 no.4
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• pp.64-68
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• 2010

Recently, MBT(Mechanical Biological Treatment) facilities were built up and operated to separate and recycle MSW(Municipal Solid Wastes)in South Korea. However, the size distribution of MSW is very rough, and it is causing operation problem because MSW would be crushed in undersize diameter by mechanical equipment before feeding each seperation process. Also, the organic material should be pre-seperated to reuse recycle material in MSW. In this research, the reactor of 1ton/batch using the super-heated steam was tested to present the separation efficiency and the size distribution of MSW by experimental factors.

• Journal of the Geological Society of Korea
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• v.54 no.5
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• pp.513-527
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• 2018

We have carried out granulometry and component analysis on pyroclastic deposits of the Maljandeung Tuff, Ulleung Island, to interpret the eruption types and prime dynamic mechanisms. It is divided into three members in the extracaldera area, each of which comprises the lithofacies of coarse tuffs and lapillistones in the lower part, and pumice deposits in upper one. The lithofacies present quantitative evidences in the granularity and component distribution patterns. As compared to the pumice deposits, the coarse tuffs and lapillistones exhibit a relative increase in both the lithic/juvenile and the crystal/juvenile ratios, and a preferential fragmentation of the juvenile fraction. The abundance of lithics and crystals in the tuffs and lapillistones can be attributed to preferential fragmentation of the aquifer-hosting rocks due to explosive evaporation of ground water, and indirect enrichment in lithics and crystals due to removal of juvenile fines from eruptive cloud. The above data exhibit that early phreatopmagmatic phase was followed by purely magmatic fragmentation phases. The coarse tuffs and lapillistones suggest phreatoplinian eruption derived from explosive interaction of magma with ground water near the conduit, while pumice deposits indicate magmatic eruption by magmatic explosion from juvenile gas pressure. In early stage, phreatoplinian eruption occurred from explosive magma/water interaction in connecting confining water with drawdown of the magma column in the conduit; Later it shifted to plinian eruption by explosive expansion of only magmatic volatiles in intercepting water influx due to higher magmatic gas pressure than confining water pressure with rising of the magma column in the conduit.

• Explosives and Blasting
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• v.28 no.1
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• pp.19-26
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• 2010

The paper presents a case study of a limestone quarry of the Philippines, where major problems in terms of improper fragmentation, poor wall control, and poor heave of the muck pile were witnessed. The paper highlights the significant role of switching over from diagonal firing pattern to V-type firing pattern, and also of making suitable adjustments in the stemming column length for improved confinement and gas retention. The study revealed that by making aforesaid design modifications in the blast round, marked improvement in blasting results was registered. Looking at the results, it was further contemplated to expand the mesh area in the subsequent blast rounds. The mesh area was incremented from the existing $8.96m^2$ to $12m^2$. The results were meticulously registered in the field, and clearly depicted definite improvements in the blast results in terms of increased P.F., reduced boulder count, reduced FEL cycle time, reduced dozing hours and improved heave.