• Resources Recycling
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• v.26 no.2
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• pp.66-70
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• 2017

The purpose of this research was to estimate density changes of sea sand by washing. To examine water content test, field density test, particle density test and measuring of dump regarding extracted sea sand and selling one. Measured result of mean particle density of barge and dump were $2.666g/cm^3$, $2.651g/cm^3$, respectively. Also, measured result of field density for each sea sand was $1.716g/cm^3$, $1.331g/cm^3$ on average. Converted to the volume of 1ton of each sea sand, $0.583m^3$, $0.751m^3$, respectively. Occurring to volume change approximately 28.8% on average. The mean field densities of measuring of sea sand that dump and barge were $1.398g/cm^3$ and $1.716g/cm^3$ respectively. This values indicated $0.715m^3$ and $0.583m^3$ each, when converted to the volume of sea sand 1ton. It was found that the average of 22.6% volume change occurred between the amount of sea sand and the sales volume.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.1
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• pp.1-14
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• 2008

Eight comprehensive oceanographic cruises on a squared $30{\times}30\;km$ area have been made to investigate the short and long-term impacts on the water qualities due to the sand mining operations at Exclusive Economic Zone (EEZ) in the central Yellow Sea from 2004 to 2007. The area was categorized to 'Sand Mining Zone', 'Potentially Affected Zone', and 'Reference Zone'. The investigation covered suspended solids, nutrients (nitrate, nitrite, ammonium, phosphate), and chlorophyll-a in seawater and several parameters such as water temperature, salinity, pH, and ORP. Additionally, several intensive water collections were made to trace the suspended solids and other parameters along the turbid water by sand mining activities. The comprehensive investigation showed that suspended solids, nitrate, chlorophyll-a and ORP be sensitively responding parameters of seawater by sand mining operations. The intensive collection of seawater near the sand mining operation revealed that each parameter show different distribution pattern: suspended solids showed an oval-shaped distribution of the north-south direction of 8 km wide and the east-west direction of 5 km wide at the surface and bottom layers. On the other hand, phosphate showed so narrow distribution not to traceable. Also ammonium showed a limited distribution, but its boundary was connected to the high nitrate and chlorophyll-a concentrations with high N/P ratios. From the last 4 years of the comprehensive and intensive investigations, we found that suspended solids, ammonium, nitrate, chlorophyll-a, and ORP revealed the sensitive parameters of water quality for tracing the sand mining operations in seawater. Especially suspended solids and ORP would be useful tracers for monitoring the water qualities of remote area like EEZ in Yellow Sea.

• 건축구조
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• v.9 no.1
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• pp.60-64
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• 2002

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.326-327
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• 2018

It is expected that the proportion of crushed aggregate will increase in order to fill the decreasing supply of sea sand in the southeast area. However, it is necessary to supply the least amount of sea sand to diversify the aggregate source, in order to minimize the mixing ratio of sea sand and crushed sand to minimize the structural stability of the concrete.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.37 no.1
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• pp.65-70
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• 2001

As consumption rate of energy increase rapidly, the facilities of fuel storage tank become large size. Almost all of the industry or public facilities storing fuel in underground fuel storage tank is manufactured by steel materials. Thus, this fuel storage tank made of steel materials is damaged by stray-current corrosion, it become destruction. If fuel storage tank is destructed, petroleum, oil and gas are leaked. So it bring about environmental pollution, energy loss, fire and explosion. Therefor, in this study, for study on the prevention of corrosion damage in underground fuel storage tank, it were investigated by corrosion and stray-current corrosion for SS 400 in dry sea sand and wet sea sand along to specific resistance. The main results obtained are as follows : As specific resistance decrease in wet sea sand, corrosion rate per year increase linearly, in case of back fill up wet sea sand in underground fuel storage tank, if the water is flow into dry sea sand, corrosion tendency of underground fuel storage tank is supposed sensitive.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.2
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• pp.143-156
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• 2014

We reviewed investigation status on turbidity plume in the statement of marine environmental survey(2008 to 2012) associated with marine sand extraction projects. The survey statement from seven marine sand extraction sites (extraction area of Southern EEZ, extraction area of Western EEZ, relocation zone in the Western EEZ, sea area under jurisdiction of Taean-gun, sea area under jurisdiction of Ansan City, and two discrete sea areas under jurisdiction of Ongjin-gun) in the nearshore and offshore of Korea showed that in situ observations were carried out for the dispersion and transport of suspended sediments on two areas (One is a extraction area in the EEZs, the other is an area of coastal sites). However, sampling station and range have not been selected considering physical, geographical factors (tide, wave, stratification, water depth, etc.) and weather conditions (wind direction and velocity, fetch, duration, etc). Especially turbidity plumes originating from three sources, which include suspended sediments in overflow(or overspill) discharged from spillways and reject chutes of dredging vessel, and resuspended sediments from draghead at the seabed, may be transported to a far greater distance outside the boundary of the extraction site and have undesirable impacts on the marine environment and ecosystem. We address that behaviour of environmental pollutants such as suspended solids, nutrients, and metals should be extensively monitored and diagnosed during the dispersion and transport of the plume. Finally we suggest the necessity to supplement the current system of the sea area utilization consultation and establish the combined guidelines on marine sand extraction to collect basic data, to monitor cumulative effects, and to minimize environmental damages incurred by the aftermath of sand extraction.

• Proceedings of KOSOMES biannual meeting
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• 2017.04a
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• pp.54-54
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• 2017

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.324-325
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• 2018

Recently, the supply and demand of aggregate in the Southeast region has been disrupted because supply of sea sand decreased due to discontinuation of collecting the EEZ aggregate in the southern sea. This study analyzed the Trends of Supply and Demand of Aggregate in the Southeastern Region of South Korea in order to find a solution these social problem.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.137-140
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• 2006

This study make an investigation into the quality of sand supplied with remicon manufacturing plant and examine concrete influenced by a source of supply of sand. As a result of the indoor test, the quality of crushed sand, EEZ sand and sand of north korea are worse than general sea sand. therefore, crushed sand, EEZ sand and sand of north sand lower quality of concrete.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.330-331
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• 2018

It's prohibited to take sand from southeastern EEZ(Exclusive Economic Zone) from January 2017 in korea. So, the supply of sea sand has been decreased and costs of sea sand are rising as a result in the southeast region. This paper deal with appropriateness of the taking sea sand, circumstance and fisheries damages by extraction of EEZ sand and proposed control measures for ensuring quality of sea sand and consider fishermen support plan for ensuring a stable supply of sand in southeast region of korea.