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Analysis Of The Effect Of Blasting Pattrerns On Ground And Building Vibration Levels Around The Mine At Blasting In Pit 2 Banko West PT Bukit Asam Tbk tanjung Enim, South sumatera Province Indra Hot Daniel Hutasoit; Irvani Irvani; Haslen Oktarianty
MINERAL Vol 5 No 1 (2020): MINERAL
Publisher : Jurusan Teknik Pertambangan Universitas Bangka Belitung

PT Bukit AsamTbk is one of the coal mining companies in Indonesia that uses an open pit mining system. Demolition of B2-C overburden rocks at the location of electrification mining in Pit 2 Banko Barat is not economical if it is doing by ripping-dozing process so that drilling and blasting activities are carried out. After blasting activities, ground vibration will arise as an effect of the blasting. It is known that the distance of the blasting location with the residential area is at a distance of 1350-1800 m for this reason that vibration measurements must be carried out with the Blasmatet III device. Ground vibration is one of the problems that must be minimized so that the ground vibration level is in accordance with SNI 7571; 2010 did not exceed the vibration threshold that could cause damages, especially for residents. The ground vibration level can be controlled in various ways such as setting the point initiation point, setting the delay time with a higher value, planning the powder factor and finally using the Air deck method. Based on research carried out for 60 days with blasting 17 times which produces different vibrations. The vibration value used for the comparison of the effects of the blasting pattern is used in 6 data, 3 data for the Box cut blasting pattern, which are 0.52, 0.53, 0.56 and for data on the Corner cut blasting pattern which is 0.63, 0.69, 0.73. While for the comparison of data using Air deck, 6 data are used, 3 values of the results of the vibration of the water deck method are 0.73, 0.69,58 and for non-Air decks the results of the vibration are 1.17, 1.05, 0, 88. Calculation of the results of the comparison of the vibration comparison using the delay time there are 6 data used, namely 3 with a delay time of 42 & 67 with the results of vibration, namely, 0.58, 0.69, 0.73 while the delay time 42 & 109 the result of vibration is 0.50, 0.56, 0.58. Of the overall soil vibration values, settlements around the blasting area are in the safe category (PVS <3 mm / s).

Analysis of Distance On Ground Vibration at Around Residential Areas in PT Semen Padang Indarung West Sumatera Province Muhammad Rizki Aulia; Irvani Irvani; Haslen Oktarianty
MINERAL Vol 5 No 1 (2020): MINERAL
Publisher : Jurusan Teknik Pertambangan Universitas Bangka Belitung

One of the blasting activity impact in Exsisting Pit by PT Semen Padang is producing the ground vibration. Analyzing the blasting distance needed to know the level of ground vibration. From that analysis, the actual value and prediction value of Peak Vector Sum (PVS) and value of vibration by SNI 7571 : 2010. The measuring of ground vibration level is done in Mess APN as residents settlement, wich is located as far as 611 meters from blasting location. The measurement starts by measuring the blasting geometry, the amount of drill hole, blasting distance, and ground vibration for about 13 data. Those data are processed using Shotplus-I to make the blasting design and the ground vibration level will be known by using blastmate. From the 13 data of ground vibration Mess APN that known on the distance 464 m the result of ground vibration is 1.651 mm/s while on the distance 478 the result of ground vibration is 2.382. Based on the result that can be seen there is an anomaly data, that caused the same blasting geometry treatment for rock structure on mine site. Beside, according measurement data wich are measured in Mess APN, the average value of ground vibration is 1.511 mm/s. It show that the ground ground vibration does not cause a significant impact in Mess APN as residents settlement and does not exceed the limit value of class 2 building category by SNI 7571:2010 (limit value is 3 mm/s)

Technical Study of Blasting Geometry and Powder Factor of Fragmentation at Pit 3 Banko Barat PT Bukit Asam Tbk Hermita Ramadhini; Irvani Irvani; Haslen Oktarianty
MINERAL Vol 5 No 1 (2020): MINERAL
Publisher : Jurusan Teknik Pertambangan Universitas Bangka Belitung

Mining PT Bukit Asam Tbk is one of the company that works in coal mining. One of the demolition activities in PT Bukit Asam Tbk is overburden stripping using drilling method and blasting. The success rate of blasting activity can be seen from the fragmentation as the blasting result, where the material size is equally spread is better than boulder. On Pit 3 Banko Barat, blasting using stemdeck results with uneven fragmentation size in condition of same powder factor and burden. This is caused by different rain intensity. Rainfall is causing blasting hole to be wet and decreasing the blasting capabilities of explosives. Blasting using stemdeck results in fragmentation average of 27.19 cm. Blasting without stemdeck based on same burden 8 m, results in fragmentation average of 46.46 cm and fragmentation size chart is obtained that shows increasing value as the powder factor from blasting geometry. That thing is contradictory with theory that the greater powder factor will result in uneven fragmentation size because it is connected with explosives usage. This condition is caused by the same doing to different rock structure on mining location in making blasting geometry design. Blasting without stemdeck based on same powder factor 0.16 kg/m3, results in fragmentation average of 66.26 cm and fragmentation size chart is obtained that is increasing as the value of burden. Smallest fragmentation value in average of 25.12 cm with 8 m burden and 0.17 kg/m3 powder factor. So if smaller fragmentation is needed in the future, then it is recommended to use smaller burden in making blasting geometry design.

Kajian Teknis Geometri Peledakan Di Pit 2 Banko Barat PT Bukit Asam Tbk, Tanjung Enim, Sumatera Selatan Masyeba Evans Lubis; Irvani Irvani; Haslen Oktarianty
MINERAL Vol 5 No 2 (2020): MINERAL
Publisher : Jurusan Teknik Pertambangan Universitas Bangka Belitung

PT Bukit Asam Tbk is one of the company that runs in coal mining at South Sumatera. One of the mining activity in PT Bukit Asam Tbk is overburden stripping using blasting method. The purpose of blasting method is to soften the hard outer layer material to ease the process of excavation using drilling and hauling instrument. Analysis of blasting geometry is done in order to get the fragmentation result that appropriate to the capabilities of drilling and hauling instrument. In the location of Pit 2 Banko Barat, blasting using air decking method that is called stemdeck is done to get better fragmentation result and less explosives usage. The research consist of 10 times blasting. The actual geometry rate here as follows 6.46 m burden, 6.40 m space, 6.75 hole depth. According to three data that are chosen in condition of same powder factor result in uneven fragmentation rate. This is caused by different rain intensity. Rainfall is causing blasting hole to be wet and decreasing the blasting capabilities of explosives. Those three explosives result in 18.22 cm of total fragmentation rate. This condition is caused by the same doing to different rock structure on mining location in the making of blasting geometry design. Fragmentation rate chart shows increasing value that follow burden value. Lowest fragmentation rate is 12.46 cm with 6.38 cm burden, 0.18 kg/m3 powder factor. So that if fragmentation needed to be lower than 12.46 cm later, it is recommended to use burden under 6.38 cm when calculating the blasting geometry design.

Kajian Teknis Sistem Jaringan Ventilasi Tambang Ciurug Level 600 PT Aneka Tambang Tbk UBPE Pongkor Leyriesa Awdina; Irvani Irvani; Haslen Oktarianty
MINERAL Vol 5 No 2 (2020): MINERAL
Publisher : Jurusan Teknik Pertambangan Universitas Bangka Belitung

According to field observation result the average dry temperature and wet temperature around between 23 – 30 ºC, with relative humidity around 83 - 93 % and contain 20.9 % O2, 4 ppm CO, on the front production there are 2 cross cut XC 636 and XC 644 have high temperature that reach 31 ºC and 100 % relative humidity. The acquired field data contain dry temperature, wet temperature, wet bulb global temperature, air velocity, and tunnel dimension so then effective temperature, work efficiency and work climate threshold value can be calculated. The result calculation get effective temperature is acquired 29 – 30 ºC, work efficiency 79 - 62 %, and climate threshold value with work arrangement as much 0 - 50 %. Technical problem on the field which causes high temperature is air recirculation from dirty air exhaust from XC 636 that is opposite with clean air direction from fan 75 kW, recirculation on access 644 from booster fan 37 kW located before XC 637 which results in increasing dirty air quantity into front production plus the second front with water puddles from drilling front roof droplets. Effort made on access XC 644 that is fan 75 kW replaced with fan 90 kW, and the tip of flexible duct extends after RC 7 so that the airflow doesn’t mix with exhaust from XC 636, aside from that booster fan 37 kW after XC 637 is moved so it help sucking dirty air from front XC 644, it can resolve air recirculation

EVALUASI HASIL PENCUCIAN RAW MATERIAL KAOLIN TERHADAP KEBUTUHAN PRODUKSI UNIT PENGOLAHAN PT ANEKA KAOLINE UTAMA BELITUNG Mukram Belto Pratama; Irvani Irvani; Mardiah Mardiah
MINERAL Vol 6 No 1 (2021): MINERAL
Publisher : Jurusan Teknik Pertambangan Universitas Bangka Belitung

PT Aneka Kaoline Utama produces kaoline powder through two processes which are washing are washing unit and processing unit. Washing unit does the separation between tailing and kaoline with the extract as the result. The extract contains water and kaoline, then the water reduction will be processed in processing unit. Based on the information, writer evaluates the extract production in washing unit for fulfilling the needs of processing unit in PT Aneka Kaoline Utama using evaluation method and action research method. The steps are sampling raw material (feed), calculating the sediment pond’s dimention and the volume of full pond, sampling tailing in washing unit’s tools, observing the production’s process, and evaluating the needs off kaoline extract. The result of this research shows that raw material in washing unit were 3,847.4 ton in April, 3,606.2 ton in May, 2,594.9 ton June, and 3,890 in July which showed the amound of extract did not reach the target in processing unit. 69.2% of loose material and 21% loosing kaolin in average caused the recovery value in washing unit just reached 30.8%. Because of loose kaoline’s presence in washing unit, writer suggests the increasing of raw material and working hour as big as 27,056.3 ton per hour with 30.8% washing unit’s recovery so the company can produce 8.34 ton kaoline per hour and 4,000 ton kaoline per month.

Analisis Ekonomis Sewa atau Beli Alat Excavator pada Kegiatan Produksi Bijih Timah PT Prima Timah Utama, Desa Cit, Kabupaten Bangka Randa Wirana; Irvani Irvani; Mardiah Mardiah
MINERAL Vol 6 No 2 (2021): MINERAL
Publisher : Jurusan Teknik Pertambangan Universitas Bangka Belitung

Fulfilling the annual production target of PT Prima Timah Utama based on the 2019 Work Plan and Budget of 1,100,000 m3 requires the procurement of adequate mining equipment both in terms of quantity and production capacity, especially excavators. The equipment procurement plan is estimated by calculating the need for tools using a sample of 30 distribution time data, 9-time constraints data, and some supporting calculation data that results in tool requirements. The cost of ownership of the equipment to be compared with the rental cost is obtained from the purchase price, interest, residual value and economic life of the equipment, the cost comparison is then analyzed using the Net Present Value method. The calculation results show that PT Prima Timah Utama must add 2 units of CAT 320D2 excavator for overburden stripping and wash with an estimated equipment cost of Rp. 2,224,076,433.6 for 2 units of new equipment and Rp. 2,541,131,520 for 2 units of rental equipment where the difference between the rental and purchase equipment is Rp. 317,055,086.4 for one year of work. The result of the analysis with the evaluation of NPV investment has a value of Rp. 32,313,773,567.7 or >0 which states that the investment is declared feasible.

Sebaran Nitrat dan Kelimpahan Fitoplankton di Pantai Tanah Merah dan Pulau Semujur Muh. Yusuf; Aditya Pamungkas; Mu’alimah Hudatwi; Irvani
Jurnal Riset Kelautan Tropis (Journal Of Tropical Marine Research) (J-Tropimar) Vol 2 No 2 (2020): November
Publisher : Universitas Hang Tuah

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30649/jrkt.v2i2.45

The waters of Tanah Merah beach waters and Semujur Islands waters are both located in Bangka Tengah Regency. Geographically it can be indicated Tanah Merah is quite far from residential areas, while the other locations are in the inhabited small island waters (Semujur). These different geographical conditions can cause the content of nitrate nutrients to be different because the main source of nitrate nutrients comes from human activities. High nitrate nutrients will affect the abundance of phytoplankton in local waters. This study aims to determine the value and nitrate in relation to the abundance of phytoplankton in the sea. Moreover this research was applied in Tanah Merah beaches waters and Semujur Island waters, Bangka Tengah Regency, from February to April 2020. The results shown that the nitrate content in Tanah Merah beaches waters was 0.011-0.026 mg/LT (St.1-St.4) which was lower compared of 0.046-0.10 mg/L (St.9-St.12) at Semujur Island waters. Phytoplankton abundance data and Species Diversity Index (H ') show that the Tanah Merah beaches waters are 111,000-134,000 cells/L and the H' index is 2.06-2.16 lower than the phytoplankton abundance data in Semujur Island waters of 110,000 - 208,000 cells/L and the H 'index of 2.22-2.29. Others evident to support that data are the current velocity in Tanah Merah beaches waters ranges from 0.014-0.21 m/s less than Semujur Island waters at 0.22-0.32 m/s.

Sebaran Nitrat dan Kelimpahan Fitoplankton di Pantai Tanah Merah dan Pulau Semujur Muh. Yusuf; Aditya Pamungkas; Mu’alimah Hudatwi; Irvani
Jurnal Riset Kelautan Tropis (Journal Of Tropical Marine Research) (J-Tropimar) Vol 2 No 2 (2020): November
Publisher : Universitas Hang Tuah

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30649/jrkt.v2i2.45

The waters of Tanah Merah beach waters and Semujur Islands waters are both located in Bangka Tengah Regency. Geographically it can be indicated Tanah Merah is quite far from residential areas, while the other locations are in the inhabited small island waters (Semujur). These different geographical conditions can cause the content of nitrate nutrients to be different because the main source of nitrate nutrients comes from human activities. High nitrate nutrients will affect the abundance of phytoplankton in local waters. This study aims to determine the value and nitrate in relation to the abundance of phytoplankton in the sea. Moreover this research was applied in Tanah Merah beaches waters and Semujur Island waters, Bangka Tengah Regency, from February to April 2020. The results shown that the nitrate content in Tanah Merah beaches waters was 0.011-0.026 mg/LT (St.1-St.4) which was lower compared of 0.046-0.10 mg/L (St.9-St.12) at Semujur Island waters. Phytoplankton abundance data and Species Diversity Index (H ') show that the Tanah Merah beaches waters are 111,000-134,000 cells/L and the H' index is 2.06-2.16 lower than the phytoplankton abundance data in Semujur Island waters of 110,000 - 208,000 cells/L and the H 'index of 2.22-2.29. Others evident to support that data are the current velocity in Tanah Merah beaches waters ranges from 0.014-0.21 m/s less than Semujur Island waters at 0.22-0.32 m/s.

Evaluasi pengaruh debit air dan laju umpan terhadap efektivitas rod mill primer PT Babel Utama Korpora Pignollee Donarthy; Irvani Irvani; Mardiah Mardiah
Jurnal Himasapta Vol 7, No 2 (2022): Jurnal Himasapta Volume 7 Nomor 02 Agustus 2022
Publisher : Universitas Lambung Mangkurat

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20527/jhs.v7i2.6442

Penggerusan merupakan tahapan inti pengolahan bahan galian. Pengukuran keefektivan penggerusan didapat dari kelolosan sebesar 80% (P80) untuk ukuran butir yang ditargetkan 18 mesh. P80 saringan 18 mesh pada Bulan Agustus 2021 didapat sebesar 59% dengan pengaturan variabel yang belum diketahui. Penelitian ini bertujuan untuk mengevaluasi efektivitas gerus Rod Mill Primer dan mendapatkan ukuran butir yang tepat pada proses konsentrasi terhadap sisa hasil pengolahan (SHP) bijih timah.Variabel yang digunakan pada penelitian yaitu debit air dan laju umpan. Percobaan dilakukan sebanyak 9 kali dengan pengaturan variabel dilakukan secara secara kombinasi. Berbagai uji atau analisis dalam penelitian, berupa sieve analysis, Grain Counting Analysis (GCA) dan analisis geokimia menggunakan X-Ray Fluorescence (XRF), serta dianalisis statistik data yang diperoleh menggunakan SPSS.SHP timah didominasi oleh mineral quartz 47,81%, dan terdapat mineral ikutan seperti limonite, monazite, muscovite, hematite, magnetite, chalcopyrite dan oksida besi. Terdapat pengaruh yang signifikan antara variabel debit air dengan P18 mesh sebesar 84,5%. Efektivitas penggerusan diperoleh pada variabel debit air tertinggi 1,75 m³/jam dan laju umpan terendah 24-26 ton/jam sebesar 82% dengan produksi 20,45 ton/jam. Optimalisasi penggerusan didapat pada variabel debit air tertinggi 1,75 m³/jam, laju umpan tertinggi 32-34 ton/jam, dengan persentase perolehan mencapai 81% dan besar produksi sebesar 27,69 ton/jam.

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