INOVASI DAN APLIKASI TEKNOLOGI PERTAMBA

" INOVASI DAN APLIKASI TEKNOLOGI PERTAMBANGAN UNTUK NEGERI"

Banjarbaru Kalimantan Selatan, 30 Juli 2011

TIM REVIEWER:

Prof. Dr. Ir. H. Rusdi HA. M.Sc Prof. Fathurrazie Shadiq, MSc Dr. Ir. Syahril Taufik, M.Sc. Eng

TIM EDITOR:

Nurhakim, MT Riswan, MT

Penerbit :

Universitas Lambung Mangkurat Press

Fakultas Teknik UNLAM

Inovasi dan Aplikasi Teknologi Petambangan untuk Negeri/Fakultas Teknik UNLAM

Banjarbaru: Universitas Lambung Mangkurat Press, 2012

256 + v hlm, 29 cm

ISBN : 978-602-992-44-8

1. Inovasi dan Aplikasi Teknologi Petambangan untuk Negeri I. Judul

Inovasi dan Aplikasi Teknologi Petambangan untuk Negeri

Hak Cipta ©2011 pada penulis Hak Cipta dilindungi Undang-Undang

Cetakan pertama, Juli 2012

Desain Cover : Rakhman Silvika Maksum

Penerbit :

Universitas Lambung Mangkurat Press Jl. H. Hasan Basry, Kayutangi-Banjarmasin 70123 Telp./Fax. 0511-3304480

Bekerjasama dengan :

Fakultas Teknik Universitas Lambung Mangkurat

Jl. A. Yani Km 36, Kampus Fakultas Teknik UNLAM Banjarbaru 70714 Telp.0511-9259966

Dep. Energy & Mineral Resources, College of Engineering, Dong-A University, Korea

840, Hadan 2- Dong, Saha-gu Busan, 604-714, Korea

PERHAPI Perwakilan KALSEL

Jl. H. Hasan Basry, Kayutangi Kampus UNLAM Banjarmasin 70123

" INOVASI DAN APLIKASI TEKNOLOGI PERTAMBANGAN UNTUK NEGERI"

Banjarbaru Kalimantan Selatan, 30 Juli 2011

TIM REVIEWER:

Prof. Dr. Ir. H. Rusdi HA. M.Sc Prof. Fathurrazie Shadiq, MSc Dr. Ir. Syahril Taufik, M.Sc. Eng

TIM EDITOR:

Nurhakim, MT Riswan, MT

Penerbit :

Universitas Lambung Mangkurat Press

"Inovasi dan Aplikasi Teknologi Pertambangan untuk Negeri"

Banjarbaru Kalimantan Selatan, 30 Juli 2011

PANITIA Steering Committee:

Pelindung

: Prof. Dr. H. Moh. Ruslan, MS

(Rektor UNLAM)

Prof. Dr. Sutarto Hadi, MSi, MSc

(PR-IV UNLAM)

(Dekan FT UNLAM) Pengarah

Ir. Noman Ruslan, MT

: Dr. Ir. Syahril Taufik, M.Sc. Eng

(PD-I FT UNLAM)

Iphan Fitrian Radam, ST, MT

(PD-II FT UNLAM)

(PD-III FT UNLAM) Penasehat

Mastiadi Tamjidillah, ST, MT

: Ir. Eddy DS, M.App.Sc

(Ketua PERHAPI Kalsel)

(Mantan KaPSTP 2005-2009) Penanggung Jawab

Ir. Adip Mustopa

: Nurhakim, ST, MT

(Ketua PSTP FT UNLAM)

M. Hijrah Salam

(Ketua BEM FT UNLAM)

Yanuar Candra

(Ketua HIMASAPTA)

Organizing Committee:

Ketua

: Riswan, MT

Wakil Ketua

: Bahrurrusydi

Sekretaris

: Hafidz Noor Fikri, ST

Wakil Sekretaris

: Indira Matahari

Bendahara

: Sari Melati, ST

Wakil Bendahara

: Edwin Noviansyah

Sie Makala/Prosidnig/ISBN

: Uyu Saimana, MT

Rizal Malik Rahmadany Maolana Dimas Apri Saputra

Sie Acara

: Untung D, ST

M. Syapril Ashari Rizky Hidayat Kurnia Rahman Ilahi

Sie Dokumentasi

: BEM & UPK Fotografi

Sie Perlengkapan/Dekorasi

: Jossi Arizon Purba

Andi Pranata Anton Ferlian Simamora

Sie Umum/Perijinan/Keamanan

: BEM FT UNLAM

M. Richy Ambadar Fantry Abdi Andreano Faisal Rijani

Sie Kesekretariatan/Pub/Humas

: Duan Arpilanoor

Lawrensa Jeriko Agus Arie Yudha Mitha Afryana

Sie Usaha/Dana

: M. Syafa Marwah

Kiki Indra Kurniawan Ariadi Prasetya

Sie Konsumsi

: Sriwahyuni, A. Ma

Mujaiyanah, A. Ma Haslinda M. Fakhry Nugraha Supriyadi Azwin Wirya Pratama

ALAMAT SEKRETARIAT:

Program Studi Teknik Pertambangan Fakultas Teknik UNIVERSITAS LAMBUNG MANGKURAT Jl. Jenderal Achmad Yani Km. 36 Banjarbaru-Kalimantan Selatan 70714 Telp.

: 0511-4773858 Fax

: 0511-4781730 E-mail

: admin@mining-unlam.ac.id , Website : www. mining-unlam.ac.id

Daftar Nama Pemakalah

No. Nama Pemakalah

Judul Makalah

Asal Instansi

1 Changwoo

Department of Lee

Asbestos particle dispersion in

the atmosphere from closed

Energy and

down mine sites

Mineral Resources Engineering Dong-A University Republic of Korea

2 Eddy Ibrahim Aplikasi Pemodelan Kedepan Jurusan Teknik

3D Ground Penetrating Radar

Eksplorasi Fakultas Teknik,

Batubara

Universitas Sriwijaya, Kota Inderalaya, Indonesia

3 H. Rusdi, H.A Kajian

Air

Danau

Fakultas Teknik

Pertambangan Untuk Air Baku

Universitas Lambung Mangkurat Indonesia

4 D.W. Kang

The Study On Blasting Effect

Department of

With Pre-Assessment Borehole

Energy and Status By Inserting Real Time Mineral Resources Borehole

Dong-A University Republic of Korea

5 Nurul Taufiqu Strategi Pengembangan Industri Pusat Penelitian Rochman

Besi/ Baja Hulu Nasional

Metalurgi LIPI,

Berbasis Bahan Baku Lokal

Puspiptek Serpong Tangsel, Banten Indonesia

6 M. Elma

Review Of Gas Diffusivity In

School of

Coal: Part 1, Preliminary

Chemical Characterisation And Novel Engineering, The High

Pressure

Multi-

University of

Component Diffusion Cell

Queensland, St. Lucia, Brisbane, QLD 4072 Australia

No. Nama Pemakalah

Judul Makalah

Asal Instansi

7 Irzal Nur

Hydrothermal

Alteration Department of Associated with the Baturappe Geological Epithermal Silver-Base Metal Engineering, Deposit,

Sulawesi, Faculty of Indonesia: Mineralogy, Zoning, Engineering, and Exploration Implications

South

Hasanuddin University, Makassar, Indonesia

8 Masagus

Jurusan Teknik Ahmad Azizi

Aplikasi Probabilistik Untuk

Pertambangan Tunggal Menggunakan Metode FTKE Universitas Bishop (Studi kasus di PT. Trisakti Jakarta Tambang Batubara Bukit Asam tbk. Tanjung Enim, Sumatera Selatan)

Analisis Kestabilan Lereng

9 Nurkhamim

Estimasi Distribusi Ukuran

Menggunakan Fakultas Teknik -

Perhitungan Split-Desktop

Universitas Lambung Mangkurat

10 Nurhakim Optimalisasi sumberdaya dan Staf Pengajar pada teknologi dalam peningkatan

Program Studi

pembangunan Di kawasan

Teknik

Timur Indonesia

Pertambangan Fakultas Teknik UNLAM

11 Adip Mustopa Prespektif Teknik Dan Ekologi Staf Pengajar pada

Pembangunan Mega Proyek

Program Studi

Pabrik Baja Krakatau Steel Di

Kalimantan Selatan

Fakultas Teknik UNLAM

12 Riswan

Biaya Pertambangan Batubara

Staf Pengajar pada

Di Indonesia

Program Studi Teknik Pertambangan Fakultas Teknik UNLAM

13 Uyu Saismana Perhitungan Sumberdaya Staf Pengajar pada

Potensi Bahan Galian Bijih Besi

Program Studi

di Bukit Batu Hitam, Kec.

Teknik

Menthobi Raya dan Kec.

Pertambangan 255

No. Nama Pemakalah

Judul Makalah

Asal Instansi

Sematu Jaya, Kab. Lamandau, Fakultas Teknik Kalimantan Tengah

UNLAM

14 Ibrahim Sota

Fakultas MIPA

Permukaan Universitas Lambung Untuk Lokasi Mangkurat, Banjarmasin

Tempat Pembuangan Sampah Di Desa Kopi, Bone Bolango

15 Agus Mirwan Studi Awal Pemanfaatan Air Program Studi

Asam

Teknik Kimia, Sebagai Koagulan Air Sungai Fakultas Teknik, Martapura

Tambang

Batubara

Universitas Lambung Mangkurat, Kota Banjarbaru, Indonesia

Program Studi Wicakso

16 Doni Rahmat

Pemurnian Etanol Dengan

Proses Adsorbsi Menggunakan

Teknik Kimia,

Fly Ash Batubara Teraktivasi

Fakultas Teknik, Universitas Lambung Mangkurat, Kota Banjarbaru, Indonesia

17 Isna Syauqiah Tinjauan Pengelolaan Lubang Program Studi

Bekas Galian Tambang Sebagai

Teknik Kimia,

Reservoar Air

Fakultas Teknik, Universitas Lambung Mangkurat, Kota Banjarbaru, Indonesia

18 Rudi Siswanto Pemanfaatan

Rongsokan

Program Studi

(Scrap) Paduan Al-Mg Sebagai

Teknik Mesin Bahan Baku Produk Pengecoran Akademi Teknik Logam Menggunakan Metode

Pembangunan

Pengecoran Tuang

Nasional (ATPN) Banjarbaru

Assalamu‟alaikum Wr. Wb.

Alhamdulil lahi robbil „alamin. Segala puji syukur kita panjatkan kehadirat Allah S.W.T., Tuhan yang Maha Esa, atas segala limpahan karunia-Nya kepada kita semua yang berupa kesehatan dan kesempatan untuk saling bertemu, bertukar ilmu, dan berdiskusi dalam kegiatan Seminar Nasional “Inovasi dan Aplikasi Teknologi Pertambangan untuk Negeri” yang dilaksanakan oleh Fakultas Teknik Universitas Lambung Mangkurat pada tanggal 30 Juli 2011 di Aula Kantor DPRD Kota Banjarbaru Propinsi Kalimantan Selatan.

Seminar Nasional deng an tema “Inovasi dan Aplikasi Teknologi Pertambangan untuk Negeri ” , bertujuan untuk menghimpun inovasi dan aplikasi teknologi dibidang pertambangan untuk mendukung pertambangan yang berkelanjutan dan bewawasan lingkungan serta menyampaikan informasi teknologi hasil penelitian dan pengkajian atau inovasi teknologi baru antara peneliti, praktisi, pengawas pertambangan dan penentu kebijakan.

Prosiding ini disusun untuk mendokumentasikan dan mengkomunikasikan hasil seminar nasional tersebut yang terangkum dalam makalah-makalah yang disajikan dalam seminar. Pada kesempatan ini kami menyampaikan terima kasih kepada para penyaji dan penulis makalah, Tim reviewer dan Tim editor serta seluruh panitia pelaksana yang telah bekerja keras sehingga prosiding ini dapat diterbitkan. Mudah-mudahan prosiding ini bermanfaat bagi pihak yang berkepentingan, utamanya akademisi, praktisi dan pengambil kebijakan pada bidang Pertambangan serta dapat bermanfaat bagi pembangunan bangsa Indonesia.

Wa ssalamu‟alaikum Wr. Wb

Banjarbaru, 30 Juli 2011

Organizing Committee

ASBESTOS PARTICLE DISPERSION IN THE ATMOSPHERE FROM CLOSED DOWN MINE SITES

Changwoo Lee, Sewon Kil, Dooyoung Kim Department of Energy and Mineral Resources Engineering Dong-A University 840 Hadan-dong, Saha-gu Busan, 604-714, Korea Phone : 051-200-7769 Fax : 051-200-7771 E-mail : cwlee@dau.ac.kr

ABSTRACT

Although all asbestos mines in Korea were closed years ago, asbestos- containing rocks such as Serpentine near mine portals and crushing sites have been exposed to weathering. In some cases those rocks were fragmented and used for improving the soil quality in the farms. Asbestos fibers liberated from the various sources now create concerns for environmental contamination, particularly soil contamination through atmospheric dispersion over an extended area. Application of the soil contamination remedy measures has been considered as the solution.

This paper aims at predicting the distribution of asbestos soil pollution and defining the area requiring remediation. Two stages of the study were carried out; (1) particulate re-entrainment study in the wind tunnel and (2) atmospheric contaminant transport simulation.

The planetary boundary layer was created to mimic the surface boundary layer in which the settled particulates are re-entrained into the air stream. Since turbulent intensity is known to be the most critical parameter to determine the re- entrainment, it was controlled during the experiments. Also the effect of the moisture content in soil samples was studied. The maximum strength of the dispersion sources defined as grams across unit area per unit time was derived for the subsequent atmospheric transport simulation study. ISCST3, the US EPA’s regulatory model, was applied to predict the short-term as well as long-term transport and settling amount. Meteorological and topographic data at the study site were used for the analysis. The final outcome will be used for determining the specific areas for soil treatment.

Keywords : Asbestos fiber; atmospheric dispersion; turbulence intensity; planetary boundary layer

1. INTRODUCTION

There were 36 asbestos mines in the southern part of Korea peninsula and in 2011 none of those mines is in operation. Most of them had been deserted and systematic restoration project hade been applied only to few mines. At most of the mines in the past, crushing and manufacturing facilities were built near the mine portals and asbestos fiber-rich dust is believed to be generated, dispersed and deposited on the nearby soil for quite some time. Fortunately, there has been no concrete data showing the risk of asbestos particles either in the soil or in the air. However, we have seen a rise in the awareness of environmental issues associated with the mined areas and among them asbestos dust topped the list. Now, in order to prevent the possible risk of human exposure, the government agencies are working together with the academic community to identify the problem status and plan the necessary restoration works.

This paper aims at studying the possibility of asbestos dust contained in the soil near the closed down mine portals and ultimately specifying the region that requires extensive restoration work. Wind tunnel was set up to simulate the dynamics within the planetary boundary layer and a series of experiments have been carried out to analyze the possibility of re-entrainment of asbestos fibers. Asbestos dust re-entrained in the atmosphere will travel long distance and its dispersion was simulated using an US EPA atmospheric dispersion model. The simulated results based on the source strength gained from the wind tunnel experiments show the amount of dust settled on the soil and the concentration in the air.

2. DEFINITION AND REGULATIONS OF THE ASBESTOS FIBERS

Asbestos is defined as a commercial term applied to the asbestiform varieties of six minerals; one Serpentine mineral Chrysotile, and five Amphibole minerals, Amosite, Crocidolite, Anthophyllite, Tremolite and Actinolite. Fibers have mean aspect ratios of 20:1 to 100:1; higher for fibers longer than 5 μm.

Fibers are very thin, usually less than 0.5 μm in diameter. In the meantime, fibers of airborne asbestos is defined by US EPA as fibers with the length longer than

0.5 μm and the aspect ratio minimum 5:1, while OSHA’s definition is a little bit different with the aspect ratio greater than 3:1. It is known that there are differences in human risk among these minerals; Crocidolite is the most risky and Chrysotile is the least. Since Asbestos fibers have relatively sharp shapes and are hardly soluble in the respiratory tract, asbestos particles can cause numerous diseases such as lung cancer, Mesothelioma, Asbestosis, Pleural diseases and so on.

In Korea, the threshold limit of asbestos fibers in the indoor air quality regulated by the government agencies is 0.01fibers/ml. It was not until there were reports of danger of human risk among the people, particularly residents near the closed down mines portals that the asbestos fibers re-entrained in the atmosphere from the mine area has caught the attention of everybody. Thus, more strict atmospheric preservation standard for the airborne asbestos dust will

be soon formulated or revised aiming at the industries emitting asbestos into the atmosphere.

3. RE-ENTRAINMENT STUDY

The study sites in this paper are three closed down asbestos mines located in Seolakmyeon, Gapyong County, Gyeonggi-do, occupying a total area of 141km 2 .

Asbestos-containing rock is Serpentine formed in the deposit by thermal processing. Since all three mines were closed down decades ago, nearby regions are developed either as residential area or farmland. Asbestos-containing rock abandoned near the portals has been weathered and has high potential to throw asbestos fibers into the air. In addition, fine particulates generated by the asbestos milling processes were often mixed with soil and used in farmland.

Figure 1 shows a typical SEM image of Chrysotile fibers found at the site and a satellite picture of the 4km x 4km area and its topographic map are included Figure 1 shows a typical SEM image of Chrysotile fibers found at the site and a satellite picture of the 4km x 4km area and its topographic map are included

Figure 1. SEM Image of Chrysotile Fibers Sampled at the Study Site

a. Satellite Picture

b. Topographic Map Figure 2. Study Site Map and Topography

3.1 Soil Particle Size Distribution

In May 2010, 30 soil samples were sampled near the portals and along a stream. Among them, one sample from the zone with higher contamination potential and two from the less risky zone were selected for the wind tunnel In May 2010, 30 soil samples were sampled near the portals and along a stream. Among them, one sample from the zone with higher contamination potential and two from the less risky zone were selected for the wind tunnel

Sieving test for particles coarser than 100 μm and Andreasen Pipette employing Stoke’s law for finer particles were applied for the analysis of all sizes.

Its purpose was to quantify the weight of particles by size dispersed during the wind tunnel experiment. No. 20, 30, 40, 60, 100, 170 sieves were used on the basis of KS2309 Korean Test Standard, and Figure 3 shows cumulative size distributions of a sample; two from the sieve test and Andreasen Pipette method, respectively and the final combined distribution. The soil sample described in Figure 3 was obtained from farmland and its size analysis shows particles less than 500 μm accounts for approximately 50%; minus 100μm, 1% and minus 10μm, 0.3%, respectively. The other two samples also show similar size characteristics.

c. Complete Size

a. by Sieving

b. by Andreasen Pipette

Distribution

Figure 3. Cumulative Size Distribution of a Soil Sample

3.2 Wind Tunnel Dispersion Test

A wind tunnel can be designed to simulate the particle dispersion phenomenon inside the planetary boundary layer. The planetary boundary layer (PBL), also called as the atmospheric boundary layer (ABL), is the lowest layer of the troposphere where wind is influenced by friction. The thickness of the PBL A wind tunnel can be designed to simulate the particle dispersion phenomenon inside the planetary boundary layer. The planetary boundary layer (PBL), also called as the atmospheric boundary layer (ABL), is the lowest layer of the troposphere where wind is influenced by friction. The thickness of the PBL

The parameters governing particle dispersion in the PBL are known to be wind speed and turbulent intensity, while separation of a particle from pile is driven by the force acting on the pile surface through pressure fluctuation. Pressure fluctuation increases with eddies and separation and is closely related to the turbulent intensity (Ogawa et al., 1991).

3.2.1 Description of Wind Tunnel The wind tunnel for dispersion test of the particles in soil samples is

designed to generate wind speed less than 15m/s which was the maximum instant speed observed over the past 5-years, and simulate the dynamics of the PBL. Figure 4 shows the 15m long wind tunnel and its cross section. An inverter- controlled centrifugal fan and a water scrubber for eliminating the dispersed particles at the discharge point are attached.

Figure 4. Schematic of The Wind Tunnel Layout

Floor mat, fence and vortex generator are installed in the 4.43m long middle section of the tunnel to simulate the PBL as shown in Figure 5. These increase surface friction and develop a boundary layer which has profiles of the vertical velocity and the turbulent intensity similar those within the PBL. Turbulence Intensity is a scale characterizing turbulence expressed as a percent. An idealized Floor mat, fence and vortex generator are installed in the 4.43m long middle section of the tunnel to simulate the PBL as shown in Figure 5. These increase surface friction and develop a boundary layer which has profiles of the vertical velocity and the turbulent intensity similar those within the PBL. Turbulence Intensity is a scale characterizing turbulence expressed as a percent. An idealized

Turbulence Intensity (T.I.) is defined in the following equation(1): T.I. = u’/U u’ = the Root-Mean-Square (RMS), or Standard Deviation, of the turbulent

velocity fluctuations at a particular location over a specified period of time U = the average of the velocity at the same location over same time period

Figure 5. Schematic of The PBL Simulator

3.2.2 Velocity and Turbulence Intensity Profiles in the Wind Tunnel Four different wind speeds were generated in the wind tunnel; 3, 7, 10 and 14.5m/s. Figure 6 shows cross-sectional velocity variation with height without and with the PBL simulator. The thickness of the PBL seems to be 12~14cm and the velocity in it varies from 1.5 to 4m/s, much less than the range of 3~13.5m/s measured above the PBL. The PBL thickness clearly decreases with increasing wind velocity. Velocities were measured by Pitot tubes and hot-wire anemometers, as moving and fixed sensors.

a. Without the PBL Simulator

b. With the PBL Simulator Figure 6. Velocity Profiles without and with the PBL Simulator

Typical values of turbulence intensity measured within the PBL with the velocity range similar to that in this study is reported to be 8~10% by Barthelmie(1999). This was very well simulated within the wind tunnel as shown in Figure 7; the simulated values were in the range of 4 to 14 %. The lateral and vertical fluctuations of the wind speed at a single location were assumed to be ignorable and only the axial component was taken into account to calculate the turbulence intensity.

a. Measured by fixed hot-wire anemometer

b. Measured with Pitot tube

Figure 7. Variation of the Turbulence Intensity

3.2.3 Dust Dispersion Experiments Approximately 1500 grams of the soil samples collected from the study site

were prepared in a sample container in the shape of a rectangular parallelopiped, 45cm long, 21cm wide and 2cm high. The container was placed on the tunnel floor within the PBL simulator section, and the top surface of container had been adjusted to the floor level during the dispersion experiment. A load cell was placed under the container and measured the weight change of the container. The subsequent weight changes in the container were interpreted as the amount of dust dispersed in to the wind tunnel. The wind speeds were 3.3, 6.6, 9.8 and 13.3m/s and the total dispersion times of individual dispersion experiments ranged from 10 to 30minutes depending on the wind speed.

Dispersion rates of the three samples expressed in terms of g/m 2 hr were in the range of 3.3 to 109.9. To derive the dispersion rate in each size interval, the

size distributions after the dispersion experiments were carried out by the identical methods applied to the previous size analysis works. Figure 8 describes the two size distributions obtained before and after the dispersion experiments for the wind speed of 13.3m/s.

c. Sample C Figure 8. Size Distributions before and after The Dispersion Experiments with the wind Speed of 13.3m/s

a. Sample A

b. Sample B

Under the assumption that the maximum particle size found in the total Under the assumption that the maximum particle size found in the total

6.1g/m 2 hr.

Table 1. Dispersion Rates of Fine Par ticles under 100μm (Sample A)

Wind Speed

Rate of Dispersion (m/s) 2 (g) (g/m hr)

Total Dispersion Weight

Figure 9. Changes in the Size Distributions by Dispersion Experiments

The effects of moisture content in soil were also tested by adjusting the water contents to 0, 5 and 10%. The tests were performed in outside environment with constant temperature and humidity in order to avoid the influences of other variables. As shown in Figure 10, the results indicate soil particles with higher water content are hard to be dispersed and fine particles in the dry soil show a 4.5times higher dispersion rate compared with the case with moisture content of 10%.

a. TSP

b. Fine particles less than 100 μm

Figure 10. Changes in the Dispersion Rate with the Moisture Content in Soil

3.3 The Results – Contamination Source Strength Since a series of qualitative preliminary study with polarization microscope

shows the Asbestos concentrations in terms of the number, individual asbestos fibers have to be characterized to convert them to the gravimetric concentration. Identification of the mass of individual fiber can allow us to calculate the dispersion weight of Asbestos fibers in the fine particle size range. A series of SEM analysis were done to obtain the aspect ratio of fiber, the ratio of length to diameter. Figure 11 shows the SEM images of Asbestos fibers, while Figure 12 includes distribution of fiber diameter and length. The average value of fiber diameter was 0.5 μm and most of the fibers were longer than 5μm. The average aspect ratio was 20:1.

a. (x 500)

b. (x 5000)

Figure 11. SEM Images of Asbestos Fibers

a. Length Distribution

b. Diameter Distribution

Figure 12. Histograms of the Length and Diameter of Asbestos Fibers

Assuming the specific weight of Asbestos is 3, the average mass of Asbestos fiber with the length of 17.5 μm and the diameter of 1.5μm can be calculated to be 5.45E-23g/m 2 s. Table 2 shows the dispersion rate of Asbestos fibers in the

samples containing 0.75% and 3% of Asbestos. These concentrations in soil samples containing 0.75% and 3% of Asbestos. These concentrations in soil

1.46E-25 to 2.21E-23g/m 2 s.

Table 2. Dispersion Rate of Asbestos Particles at the Study Site Asbestos Concentration (% by

Contamination Source Strength

number) 2 (g/m s) Sample containing 0.75%

1.46E-25 Asbestos

Sample containing 3% 2.21E-23 Asbestos

4. ATMOSPHERIC DISPERSION SIMULATION

A series of 3D atmospheric dispersion simulation using US EPA model ISCLT3 were performed to estimate the short-term as well as long-term dispersion of Asbestos particles. The simulation study can provide the Asbestos concentration in the air and soil. All the topographical data such as Transverse Mercator Coordinates and elevations were employed, while the past weather data were obtained from the nearby meteorological observation station. Precipitation data were used to estimate the moisture content in the soil and subsequently the contamination source strength which has the moisture-dependent characteristics

shown in Figure 10. The size of contamination source was assumed to 30x30m 2 which approximates the exposed area near the mine portals.

Figure 13 summarizes the distribution of wind direction and speed observed at the nearby monitoring station in 2008. This was used for the simulation analysis.

a. Wind Direction

b. Wind Speed

Figure 13. Annual Distribution of Wind Direction and Speed

4.1 Annual Deposition of Asbestos Particles The first simulation analysis aims at estimating the average concentration

in the air and the deposition amount of Asbestos particles per year from all three contamination sources. Figure 14 summarizes the simulation results, while the values in contour maps for the airborne dust concentration and soil deposition rate

are in -18. μg/m and g/m , respectively and have to be multiplied by 10 The regions within 260m, 300m, 280m from Portal A, B and C show the

deposition rate higher than 1 X 10 2 g/m and these values are significantly less than 0.4g/m 2 at the depth of 2.5cm, NEN 5707 (Netherlands Standard for Asbestos

-21

content). In the meantime, the Asbestos concentration in the air was not serious at all since the concentrations within the air, 210m, 280m and 200m from the

portals are well below 5.45 x 10 3 μg/m the converted TLV of NEN 5707. .

-14

a. Concentration in the Air

b. Deposition Rate on the Surface

Figure 14. Annual Concentration in the Air and Deposition Rate of Asbestos Particles

4.2 Seasonal Deposition of Asbestos Particles from Three Closed Down Mine Portals

The seasonal variation of simulation results was also analyzed. Figure 15 describes the soil contamination rate by season. The results only for summer with stronger wind and spring with lower humidity are included in the figure.

In summer, the regions within 300m, 290m and 240m from three mine

portals show deposition rate higher than 2.5x10 2 g/m , while less amount of Asbestos particles is shown to be deposited in spring. Regardless of the seasonal

variation, the soil in all the regions does not seem to be affected seriously by Asbestos particle dispersion.

a. In Summer

b. In Spring

Figure 15. Seasonal Variation of Deposition Rate of Asbestos Particles

4.3 Deposition of Asbestos Particles for the Five-year Period from Three Closed Down Mine Portals

A longer-term simulation was done for 5-years. All the scenario data were identical to those in the previous simulations. Figure 16 illustrates the results; the estimated deposition rate within the distance of approximately 400m from

three portals was 1.5x10 2 g/m , considerably less than NEN 5707, 0.4g/m at the depth of 2.5cm.

Figure 16. Deposition Rate of Asbestos Particles for 5-years Period

4.4 Deposition of Asbestos Particles under the Worst Scenario-All Three Mines in Operation

Scenarios for the worst case would be the cases when three mines are assumed to be in operation. These scenarios will provide information about the soil contamination from three mines in the past. For the worst cases, all the fine particles dispersed are assumed to be Asbestos fibers; the contamination strength

of 1.69x 10 2 g/m s. The simulation results for 5-years period from the worst scenario are summarized in Figure 17. Within the distance, 300~320m from the

portals, the deposition rates are higher than NEN 5707 and indicate that soil in the vicinity of portals had been contaminated in the past for a quite long period through the atmospheric dispersion.

Figure 17. Deposition Rate of Asbestos Particles for 5-years Period

5. CONCLUSIONS

This paper aims at analyzing the possibility of human risk created by the atmospheric dispersion of Asbestos particles from closed down mines. A wind tunnel was used to simulate the dynamics within the planetary boundary layer near the earth surface and the strength of Asbestos contamination source was quantified. Consequently, the atmospheric dispersion was simulated to identify This paper aims at analyzing the possibility of human risk created by the atmospheric dispersion of Asbestos particles from closed down mines. A wind tunnel was used to simulate the dynamics within the planetary boundary layer near the earth surface and the strength of Asbestos contamination source was quantified. Consequently, the atmospheric dispersion was simulated to identify

The results can be summarized as follows: (1) The PBL can be well created in the wind tunnel through characterizing the vertical profiles of wind speed and turbulence intensity. (2) The turbulence intensity, the governing variable for particle re-entrainment, ranged from 4 to 14% in the wind tunnel, compared to those of 8~10% in the PBL.

(3) With the wind speed less than 15m/s, the dispersion rate of fine particles

less than 100 2 μm was in the range of 5.5x10 and 1.69x10 g/s m . (4) Asbestos fibers in the study site have the mean length of 17.5 μm and the

mean diameter of 1.5 μm. Based on this aspect ratio, the Asbestos fiber dispersion rates range from 1.46E-25 to 2.21E-23 g/m 2 s.

(5) The simulation results shows that after several decades since mines were closed down, none of the regions near the mine portals was found to be contaminated by Asbestos. However, another simulation with the scenario of three mines in operation clearly indicates that the area within approximately 300m from the portals would have been seriously contaminated by the dispersed Asbestos particles.

(6) At present, in the vicinity of mine portals, there is no possibility of human risk created by Asbestos. This is found to be true at least in the study site of this paper.

6. ACKNOWLEDGMENTS

The authors gratefully acknowledge MIRECO (Mine Reclamation Corporation) for providing financial support and necessary resources that have contributed to the research results reported within this paper.

7. REFERENCES

S.Y. Yoo, W.S. Shim and S.C. Kim, 2005. A Study on the Pollutant Dispersion over a Mountain Valley Region (Ⅰ) : Wind Tunnel Experiments. Journal of Society of Air-Conditioning and Refrigerating Engineers of Korea, vol.17, no.11, pp. 1050~1059.

J.G. Jhun, 1995. Characteristics of Turbulence Intensity in the Surface Layer for the Various Static Stabilities in South Korea. Journal of The Korean Meteorological Society, vol.31, no.2, pp. 169~185.

Ogawa, T., Nakayama, M., Murayama, S. and Sasaki, Y., 1991. Characteristics of Wind Pressure on Basic Structures with Curved Surfaces and Their Responses in Turbulent Flow. Journal of Fluid Mechanics, vol. 38, pp. 427~438.

J.G. Kim, K.H. Choi, S.J. Oh, Y.J. Chung, D.G. Kang and J.C. Lee, 1994. Classification of the Length of Ceramic Fibers by Settling Process. Journal of The Korean Ceramic Society, vol.3, no.2, pp. 161~170.

R. J. Barthelmie , 1999, Monitoring Offshore Wind and Turbulence Caracteristics in Denmark, BWEA

T. Allen, 1997. Particle Size Measurement, fifth ed. Chapman, London, pp. 33~36.

C.K. Bong, S.D. Kim and H.K. Lee, 2000. The Effect of Similarity Condition for the Test Results in a Wind Tunnel Test. Journal of Korean Society for Atmospheric Environment, vol.16, no.4, pp. 351~361.

C.W. Park, S.J. Lee, 2004. Wind Tunnel Experiment on Porous Wind Fence for Abating Wind Erosion of Coal Dusts in POSCO KwangYang. Journal of The Wind Engineering Institute of Korea, vol. 2, no.1, pp. 115~126.

APLIKASI PEMODELAN KEDEPAN 3D GROUND PENETRATING RADAR (GPR) UNTUK EKSPLORASI BATUBARA

Eddy Ibrahim 1

1 Jurusan Teknik Pertambangan, Fakultas Teknik, Universitas Sriwijaya, Kota Inderalaya, Indonesia

eddy_ibrahim@yahoo.com

ABSTRAK

Pemodelan forward modeling 3D dengan melakukan variasi orientasi antena dengan arah dari bidang-bidang pecah dibuat kearah y dan arah polarisasi medan listrik dari antena sejajar dengan bidang-bidang pecah memperlihatkan batas batubara dengan lempung secara vertikal lebih tegas sedangkan jika arah dari bidang-bidang pecah dibuat kearah y dan arah polarisasi medan listrik dari antena tegak lurus dengan bidang-bidang pecah dapat memperlihatkan bidang-bidang pecah batubara secara lateral lebih tegas. Implementasi dilapangan antara hasil pengukuran lapangan telah sesuai dengan hasil pemodelan. Untuk kasus pemodelan batubara dan lempung fenomena ring down akan selalu ada dalam akuisisi data dikarenakan secara fisik batubara berlapis-lapis dan mempunyai bidang-bidang pecah secara tidak beraturan.

Kata kunci : Forward modeling 3D, orientasi antena, batubara dan lempung, bidang pecah, polarisasi medan listrik, sejajar dan tegak lurus.

1. PENDAHULUAN

Permasalahan dengan penggunaan variasi orientasi antena berkaitan dengan munculnya fenomena ring down yang muncul di radargram terukur. Ring down merupakan suatu fenomena yang ditimbulkan akibat adanya impedansi yang tidak tepat antara antena ( transmitter dan receiver ) dan batubara. Polanya di radargram terukur sangat mengganggu pada saat interpretasi. Kenampakannya hampir mirip dengan lapisan-lapisan dengan intensitas medannya cukup kuat. Berkaitan dengan timbulnya pola tersebut maka pemodelan kedepan 3D perlu dilakukan. Model 3D dibuat untuk melihat pengaruh variasi arah antena (polarisasi) terhadap variasi arah bidang-bidang pecah di batubara. Arah dari bidang-bidang pecah ditentukan sejajar dan tegak lurus terhadap arah polarisasi dari antena dipole listrik. Untuk bidang- bidang pecah yang dibuat dalam model 3D tersebut diisi dengan air.

Pemodelan 3D juga untuk mengkaji signature batubara pada radargram yang tidak mudah dikenali dan untuk membuktikan apakah ada kesesuaian antara hasil pemodelan dengan hasil pengukuran lapangan berdasarkan penggunaan variasi orientasi antena. Pemodelan ini dapat digunakan untuk optimalisasi parameter pengukuran di lapangan (orientasi antena dan frekuensi antena). Sehingga untuk reduksi efek yang ditimbulkan dalam radargram hasil pengukuran dapat lebih mudah. Pemodelan kedepan 3D untuk batubara dan lingkungannya menggunakan

tm program simulator Reflexw versi 3.05.

2. METODE

Tipe antena yang digunakan dalam pemodelan diasumsikan menghasilkan orientasi polarisasi medan listrik linear tegak lurus terhadap arah perambatannya (k) (gambar 1).

Gambar 1. Hubungan antara E , H , k

Sesuai dengan teori, transversalitas hubungan antara E dan H diperoleh dari persamaan Maxwell,   maka diperoleh . . E 0 kE  yang berarti 0 k  . Dari E

persamaan Maxwell,    E    , dengan mengandaikan bentuk

solusinya dalam bentuk persamaan Ext ,  E 0 exp  i t  kx . 

     . Maka untuk

. Jadi E , H , ˆ k  saling tegak lurus  seperti diperlihatkan oleh gambar 1 (Jackson, 1975) :

diperoleh H

E . Maka E  H E

Berdasarkan gambar 1, untuk gelombang yang merambat kearah x positif, komponen medan listrik E dan komponen medan magnet H saling tegak lurus, tegak lurus terhadap arah perambatan ˆ k , dan selalu sefase pada setiap titik dengan

perbandingan magnitude :

; yang hanya bergantung pada sifat

medium. Karena v 

0, maupun  , maka gelombang elektromagnetik tidak mungkin

hanya terdiri dari E atau H saja ( Jackson, 1975).

Pemodelan ini dilakukan karena pada pengukuran GPR skala lapangan pada lapisan batubara terdapat banyak bidang-bidang pecah baik yang paralel maupun tegak lurus terhadap bidang-bidang perlapisan batubara. Untuk posisi dari geometri batubara dan lapisan lempung yang dimodelkan sesuai dengan lapangan. Dalam pemodelan ini ditentukan lapisan batubara terletak dipermukaan sedangkan lapisan Pemodelan ini dilakukan karena pada pengukuran GPR skala lapangan pada lapisan batubara terdapat banyak bidang-bidang pecah baik yang paralel maupun tegak lurus terhadap bidang-bidang perlapisan batubara. Untuk posisi dari geometri batubara dan lapisan lempung yang dimodelkan sesuai dengan lapangan. Dalam pemodelan ini ditentukan lapisan batubara terletak dipermukaan sedangkan lapisan

Gambar 2. Gambaran arah polarisasi (arah y) dan arah perambatan medan Listrik

(arah x) pada batubara (dengan bidang-bidang pecah ke arah y) Dari kedudukan antena seperti gambar 2 dengan asumsi bidang-bidang pecah

dari batubara kearah sumbu y maka medan listrik akan tereksitasi (amplitudo gelombang mengecil akibat teratenuasi oleh air yang mengisi bidang- bidang pecah). Untuk pemodelan lapisan batubara terletak dipermukaan sedangkan lapisan lempung terletak dibawahnya dan arah dari bidang-bidang pecah dibuat kearah y dan arah polarisasi medan listrik dari antena tegak lurus dengan bidang-bidang pecah dapat dilihat pada gambar 3.

Gambar 3. Gambaran arah polarisasi (arah x) dan arah perambatan medan listrik(arah y) pada batubara (dengan bidang-bidang pecah ke arah y) dan lempung

Untuk kedudukan antena seperti gambar 3 dengan asumsi bidang-bidang pecah dari batubara kearah sumbu y maka medan listrik tereksitasi (amplitudo gelombang mengecil akibat energinya habis terpantulkan oleh bidang-bidang pecah dan kandungan air yang mengisi bidang-bidang pecah).

3. HASIL

Untuk model 3D, panjang batubara kearah x = 3 m sedangkan lebarnya kearah y = 4 m. Tebal batubara yaitu 0.6 m sedangkan tebal lempung yaitu 0.4 m. Pada batubara terdapat bidang-bidang pecah berisi air dengan dimensi 0.1 m. Permitivitas relatif batubara yaitu 5.86 sedangkan permitivitas relatif lempung yaitu 16. Permitivitas air digunakan 80.0. Gambaran model batubara beserta bidang-bidang pecah dan lapisan lempung dibawahnya dapat dilihat pada gambar 4.

Gambar 4. Model Batubara Beserta Bidang-bidang Pecah Dan lapisan Lempung dibawahnya

Untuk arah polarisasi listrik kearah y (sejajar dengan bidang-bidang pecah) dengan dimensi dari model seperti gambar 4 maka hasil dari penggunaan program simulator Reflex 3.05 beserta spesifikasi-spesifikasinya dapat dilihat pada gambar 5.

Gambar 5 : Hasil simulasi terhadap gambaran model batubara beserta bidang- bidang pecah dan lapisan lempung dibawahnya dari gambar 4 (arah polarisasi ke Y)

Posisi lapisan batubara pada jendela waktu antara 0.6 ns sampai dengan 14.0 ns. Nilai intensitas dari batubara warna ungu sedangkan bidang-bidang pecah berwarna biru tua. Medan listrik dalam pemodelan ini akan tereksitasi (amplitudo gelombang mengecil akibat teratenuasi oleh air yang mengisi bidang-bidang pecah) dan juga tidak terjadi kontras antara air yang mengisi bidang pecah dengan batubara. Pemodelan dengan cara ini akan memperlihatkan batas batubara dengan lempung secara vertikal lebih tegas.

Untuk arah polarisasi listrik kearah x (tegak lurus bidang-bidang pecah) dengan dimensi dari model seperti gambar 4 maka hasil dari penggunaan program simulator Reflex 3.05 beserta spesifikasi-spesifikasinya dapat dilihat pada gambar 6.

Gambar 6 : Hasil simulasi terhadap gambaran model batubara beserta bidang- bidang pecah dan lapisan lempung dibawahnya dari gambar 4 (arah polarisasi ke X)

Posisi lapisan batubara pada jendela waktu antara 0.6 ns sampai dengan 14.0 ns. Nilai intensitas dari batubara warna ungu sedangkan bidang-bidang pecah berwarna biru tua. Medan listrik dalam pemodelan ini kurang tereksitasi (amplitudo gelombang besar karena tidak teratenuasi oleh air yang mengisi bidang-bidang pecah) dan juga terjadi kontras antara air yang mengisi bidang pecah dengan batubara. Sehingga pemodelan dengan cara penempatan antena dengan model batubara dan lempung tersebut akan dapat memperlihatkan bidang-bidang pecah batubara secara lateral lebih tegas.

Sebagai perbandingan hasil pengukuran lapangan diterapkan pada model fisik batubara seperti gambar 7 menunjukkan kesesuaiannya terhadap kedua hasil model diatas.

Gambar 7. Foto fisik singkapan batubara yang diukur

Adapun kedua radargram hasil pengukuran untuk kedua cara diatas dapat dilihat pada gambar 8a dan 8b.

Gambar 8 . hasil pengukuran radargram

4. KESIMPULAN

Pemodelan 3D dengan forward modeling dengan melakukan variasi orientasi antena dengan objek target batubara dan lempung dimana batubara dibuat adanya bidang-bidang pecah telah menunjukkan hasil yang berbeda. Perolehan dari hasil pemodelan untuk kedua kasus 3 D secara umum dapat memberikan informasi posisi batas batubara dan lempung secara tegas berdasarkan signature nya (bentuk gelombang) untuk kasus dimana orientasi antena adalah sejajar bidang pecah batubara sedangkan untuk kasus dimana orientasi antena tegak lurus bidang pecah akan lebih mempejelas posisi dan orientasi bidang pecah. Secara lapangan hasil pengukuran lapangan telah sesuai dengan hasil pemodelan. Untuk kasus pemodelan batubara dan lempung fenomena ring down akan selalu ada dalam akuisisi data dikarenakan secara fisik batubara berlapis-lapis dan mempunyai bidang-bidang pecah secara tidak beraturan.

5. UCAPAN TERIMA KASIH

Kerja yang telah dilakukan ini dibantu oleh Laboratorium Fisika Bumi ITB dan Laboratorium Eksplorasi dan Hidrologi Jurusan Teknik Pertambangan Fakultas Teknik Universitas Sriwijaya. Saya mengucapkan terimakasih kepada Dekan Fakultas Teknik Universitas Sriwijaya, Rektor Universitas Sriwijaya Atas bantuan keuangan untuk dapat menghadiri dan Mempresentasikan Tulisan ini dalam Seminar Nasional. Khusus kepada Ir. Syaiful Islam, Gunawan Handayani, MSCE, Ph.D, DR. Bagus Endar NH atas masukan- masukannya, DR. Surono, Muslim Nugraha, Ssi, Karlan Ssi, Yonathan Ssi, Erlan Dan seluruh yang membantu dalam penyelesaian tulisan ini.

6. DAFTAR PUSTAKA

Annan A, P, (2001) Ground penetrating radar, workshop notes, sensors & software, Ontario, Canada.

Engheta N. and Papas C.H, (1982) Radiation patterns of interfacial dipole antenna, Radio science 17, 1557-1566.

Giannopoulos. A. , (2003) G PR M AX 2D/3D user’s manual version 1.5, University of Edinburgh, School of engineering and electronics, institute for infrastructure and environment, Crew building, The King’s buildings, Edinburgh, EH9 3JN,

Scotland. Ibrahim E, and Hendrajaya. L and Handayani. G and Fauzi. U and Islam.S. (2003a),

Determination study of coal seams thickness by using GPR method and presented a oral presentation at Joint Convention Jakarta 2003, The 32nd IAGI and the 28th HAGI annual convention and exhibition , Proceedings, 2003

Ibrahim, E., and Hendrajaya. L and Fauzi. U and Handayani. G and Islam. S. (2004c), Determination of geometry and bedding plane orientation in coal seam use of GPR method and presented a poster presentation in session

T08.04, “Magnetotellurics” at nd 32 International Geological Congress , Florence, Italy, Expanded abstract, August, 27, 2004.

Ibrahim, E., (2005) Studi penggunaan GPR multi konfigurasi pada tahap eksploitasi batubara (studi kasus pada tambang batubara Bukit Asam, Tanjung Enim, Sumatera Selatan), Disertasi Doktor (S 3), Program Studi Fisika, FMIPA, ITB (tidak dipublikasikan).

Interpex, (1996), The definitive solution for Ground Penetrating Radar processing and interpretation. GRADIX software ver. 1, Colorado.

K.J. Sandmeir,(2004), REFLEXW- The 2D processing and 2D/3D interpretation software for GPR, reflection seismics and refraction seismics for windows 9?/2000/NT/XP, Sandmeier scientific software, Zipser strabe 1 D-76227 Karlsruhe, Germany.

Ramac/GPR, (1997), Software manual version 2.28. MALA, Geoscience. Yee, K.S, (1966), Numerical solution of initial boundary value problems involving

Maxwell’s equation in isotropic media. IEEE transactions on antennas and propagation , Vol. 14 pp.302-307.

KAJIAN AIR DANAU PERTAMBANGAN UNTUK AIR BAKU

1 H. Rusdi, H.A 2 , Nurhakim

1 Guru Besar Fakultas Teknik Universitas Lambung Mangkurat Indonesia

2 Dosen Program Studi Fakultas Teknik Universitas Lambung Mangkurat Email : nurhakim@ft.unlam.ac.id

ABSTRAK

Lubang-lubang itu berpotensi menimbulkan dampak lingkungan jangka panjang, terutama berkaitan dengan kualitas dan kuantitas air. Air asam tambang mengandung logam-logam berat berpotensi menimbulkan dampak lingkungan dalam jangka panjang, sehinggga salah satu permasalahan adalah bagaimana memanfaatkan air danau tambang tersebut. Industri pertambangan menghasilkan dan membuang jutaan meter kubik air setiap harinya bersumber dari air permukan dan air tanah. Air ini akan menjadi permasalahan pencemaran air di dalam dan di sekitar daerah pertambangan apabilah tidak dikeloladenganbaik karena pH 2-6, tetapi air ini juga akan bermanfat apabilah mutunya memenuhi standar mutu air baku (pH 7-9). Untuk menaikkan pH air asam tambang dilakukan proses pengapuran, yaitu mencampurkan antara kapur tohor dengan air asam tambang, sehingga menyebabkan pH air tambang menjadi naik sampai pada batas baku mutu air yang dapat digunakan untuk kebutuhan sehari-hari. Berdasarkan pengujian lapagan untuk menetralkan air

sebanyak 1 m 3 dari pH 2.78 menjadi pH 7 diperlukan kapur tohor sebanyak 0,7 kg. Dengan biaya pengolahan sebesar Rp. Rp. 444.4/m 3 maka sebenamya industri mampu

untuk melakukannya, tinggal bagaimana kesadaran dari masyarakat industri terhadap lingkungan.

Kata kunci : Air asam tambang, danau Pertambangan, Air Baku

1. LATAR BELAKANG

Kegiatan pertambangan merupakan kegiatan usaha jangka panjang yang kompleks dan sangat rumit, sarat risiko, melibatkan teknologi tinggi, padat modal, dan aturan regulasi yang dikeluarkan dari beberapa sektor. Selain itu, kegiatan pertambangan mempunyai daya ubah lingkungan yang besar, sehingga memerlukan perencanaan total yang matang sejak tahap awal sampai pasca tambang. Industri pertambangan pada pasca operasi akan meninggalkan banyak warisan yang memiliki potensi bahaya dalam jangka panjang, antara lain; Lubang tambang (Pit), Air asam tambang (Acid Mine Drainage) dan lain-lain.

Industri pertambangan di Indonesia Sebagian besar dilakukan dengan cara terbuka. Ketika selesai beroperasi, perusahaan meninggalkan lubang-lubang raksasa di bekas areal pertambangannya. Lubang-lubang itu berpotensi menimbulkan dampak lingkungan jangka panjang, terutama berkaitan dengan kualitas dan kuantitas air.