Changes in groundwater levels in the indutrial area were seen on ground air maps from the Directorate of Environmental Geology in 2003 and 2010. Digitization of groundwater level maps was carried out and then the changes were analyzed for getting the volume of water used. Time-lapse microgravity is sensitive to density changes. To get the value of density changes of groundwater, we need information such as rock porosity and water density. In this case we assumed that the porosity value is 30% and the water density value is 1 gr / cc, so the value of water density changes is 0.3 gr/cc. The value of density changes is distributed across the entire volume of groundwater changes during 2003 to 2010. The volume of groundwater changes in interval 2003 to 2010 was around 33,971,200 m3. From calculation of time-lapse microgravity for geometry the reduction of groundwater in the Dayeuhkolot industrial area shows the highest value about -125 microGal. The time-lapse microgravity of the Dayeuhkolot industrial area during 2003 to 2010 shows a value -125 microGal which is very detectable with a gravimeter like Scintrex CG-5 which has accuracy up to 1 microGal.
Abstract. Conveyor is one of the tools that is used to move excavated materials such as coal. Conveyor structure is made of carbon steel. However, the conveyor structure can experience a decrease in quality due to corrosion that occurs due to direct contact with coal impurities and its environment. This research was conducted on a conveyor structure consisting of 2 segments with 16 test points along 60 meters. This study aims to determine the type of corrosion, corrosion control conditions applied coating. Methodology in this research is measuring the thickness reduction of the conveyor structure. In this study, observations of environmental conditions include an average air temperature of 280C, an average rainfall of 233 mm and, relative humidity of 87%. The actual thickness measurement of the conveyor structure is using the Ultrasonic Thickness Gauge TT 130. Type of corrosion that occurs in the conveyor structure is uniform corrosion. The corrosion control method applied to the conveyor structure is the coating method. The applied coatings are primer coating using Seaguard 5000, intermediate coating using Sherglass FF and, top coating using Aliphatic Acrylic Modified Polyurethane. Abstrak. Conveyor merupakan salah satu alat yang digunakan untuk memindahkan material bahan galian seperti batubara. Struktur conveyor yang digunakan berbahan dasar baja karbon. Namun demikian struktur conveyor dapat mengalami penurunan kualitas yang diakibatkan oleh korosi yang terjadi karena kontak langsung dengan pengotor batubara dan lingkungannya. Penelitian ini dilakukan pada struktur conveyor yang terdiri dari 2 segmen dengan 16 test point sepanjang 60 meter. Penelitian ini bertujuan untuk mengetahui jenis korosi, kondisi pengendalian korosi yaitu coating yang diaplikasikan. Metodologi dalam penelitian ini adalah pengukuran pengurangan ketebalan struktur conveyor. Pada penelitian ini, pengamatan kondisi lingkungan meliputi temperatur udara rata-rata 280C, curah hujan rata-rata 233 mm dan kelembapan relatif 87%. Pengukuran tebal aktual struktur conveyor dilakukan dengan menggunakan alat Ultrasonic Thickness Gauge TT 130. Jenis korosi yang terjadi pada struktur conveyor yaitu korosi merata. Metode pengendalian korosi yang diaplikasikan pada struktur conveyor yaitu metode coating. Coating yang digunakan adalah primer coating menggunakan Seaguard 5000, intermediate coating menggunakan Sherglass FF dan top coating menggunakan Aliphatic Acrylic Modified Polyurethane.
Pangalengan is located between 107 o 29'-107 o 39 'BT and 7 o 19'-7 o 6' LS. Based on its topography and geological condition, Pangalengan has steep slopes and lies between two strike-slip faults. Average annual rainfall of this area is about 1,996 mm with 5.47 mm of average daily rainfall. The area is about 27294.79 hectares with population of 148353 inhabitants. According to these data, Pangalengan has high risk of landslide. Landslide occurred in Pangalengan on 05-05-2015 at 14:00 pm, caused 9 fatalities, 4 people seriously injured, 134 people evacuated, 10 houses buried, geothermal steam flow pipe of Energy Star damaged. It is necessary to analyze slope morphology and study the potential hazard areas of landslide. The result shows that Cibitung which has steep (35o-45o) and very steep (45 o-65 o) slope is prone to landslide with an area of ± 3038 hectares spread to the south.
In open mining systems, the most important problem in mining production activities is surface water management, where surface water management is an integrated water management activity with the aim of minimizing the negative influence of surface water which consists of mine drainage methods, mine drainage, sediment separation and control. Geographic Information Systems (GIS) can be used for hydrological analysis using spatial data, especially in calculating runoff discharges from surface water. The method used in calculating runoff discharge is in the form of daily rainfall data. This rainfall data can show the influence of the catchment area which is useful for knowing precisely and accurately the runoff water discharge. Geographic Information Systems (GIS) are used to calculate variables in rational formula equations by overlay analysis. Information about digital-based hydrological conditions is very useful as a means of decision making and policies undertaken in monitoring hydrological conditions in open mines. By using a geographic information system (GIS) with a geodatabase attribute, it can be used to view general conditions in a mining area in monitoring hydrological conditions. So it is very appropriate to be used as hydrological monitoring in the mining area in making decisions that are fast, precise and accurate. Apart from that the geodatabase attribute can see the actual conditions of a mining area.
Abstract. In its production activities, this company uses 1 unit of Caterpillar 345 GC excavation equipment which has been used for production for 2 years and 3 units of new Hino 500 New Ranger FM 260 JD production for 4 years. The condition of mechanical equipment that is classified as old and unfit for operation due to frequent breakdowns and requiring special maintenance and equipment operating costs are getting bigger, Of course it will affect productivity and production which will decrease. Therefore, so that the mining activities carried out are not disturbed due to equipment problems that often experience damage, it is necessary to replace the equipment. In planning the replacement of mechanical equipment, it is necessary to conduct a technical and economical study. For a technical study, it includes a study of equipment production, and for an economic study it includes operating costs, as well as ownership costs, Present Worth Cost value and Production Unit Cost value. Based on the results of a technical study, the digging tool has a work efficiency of 49.86% with a production of 271,384.18 BCM/Year and the old conveyance has a work efficiency of 86.03 % with a production of 270,996.93 BCM/year, As for the new means of transportation, it has a work efficiency of 86.95% with a production of 305409,91 BCM/Year. Based on the results of the economic study, it was found that the operating costs of the old conveyances were Rp 621,884,172.20 /year, and for the operating costs of the new conveyances, it was Rp 552,566,994.26 /year. In addition, the results of the calculation of Production Unit Cost for old transportation equipment are also obtained, which is Rp 3,100.46/BCM, while for new means of transport it is Rp 2,585.07/BCM. Abstrak. Dalam kegiatan produksinya perusahaan ini menggunakan alat gali-muat Caterpillar 345 GC sebanyak 1 unit yang telah digunakan untuk produksi selama 2 tahun, 3 unit alat angkut baru Hino 500 Ranger FM 260 JD baru yang sudah beroperasi selama 4 tahun. Kondisi dari alat mekanis yang sudah tergolong tua dan tidak layak beroperasi karena sering terjadi kerusakan dan membutuhkan perawatan yang khusus dan biaya operasi alat semakin besar, tentunya mempengaruhi produktivitas dan produksi yang akan semakin menurun. Oleh karena itu agar kegiatan penambangan yang dilakukan tidak terganggu karena masalah alat yang sering mengalami kerusakan maka perlu dilakukan penggantian alat. Dalam merencanakan penggantian alat mekanis maka perlu dilakukan kajian secara teknis dan ekonomis. Untuk kajian teknis meliputi kajian produksi alat, serta untuk kajian ekonomi meliputi biaya operasi, biaya kepemilikan, nilai Present Worth Cost serta nilai Production Unit Cost. Berdasarkan hasil kajian teknis, alat gali-muat mempunyai efisiensi kerja 49,86% dengan produksi sebesar 271.384,18 BCM/Tahun dan alat angkut lama mempunyai efisiensi kerja 86,03% dengan produksi sebesar 270.996,93 BCM/Tahun, Sedangkan untuk alat angkut baru mempunyai efisiensi kerja 86,95% dengan produksi sebesar 305.409,91 BCM/Tahun. Berdasarkan hasil kajian ekonomi didapatkan hasil biaya operasi alat angkut lama sebesar Rp 621.884.172,20 /tahun, dan untuk biaya operasi alat angkut baru adalah sebesar Rp 552.566.994,26 /tahun. Selain itu didapatkan juga hasil perhitungan Production Unit Cost alat angkut lama yaitu sebesar Rp 3.100,46/BCM, sedangkan untuk alat angkut baru yaitu sebesar Rp 2.585,07/BCM.
Bandung basin is the center of the population at West Java, and several Industrial areasis. In supporting its sustainability, water needs is one of the factors that must be fulfilled. The water needs are obtained by taking water directly from groundwater. Excessive extraction of groundwater can cause damage, the impact of which is the more difficult it is to obtain groundwater and cause environmental disaster in the form of land subsidence. Using the vertical gravity gradient technique in the Bandung basin area is expected to map the critical groundwater damage zone. The results from the vertical gravity gradient area of the Bandung basin map, the region of groundwater with critical status are found in almost all cities, except in the Baleendah area to Ciparay and Soreang to the south of Cimahi.
The importance of the need for water causes water to become a major factor in the sustainability of existing mining activities. In addition, the occurrence of silt deposition in the main pond is a separate problem which is very likely to cause silting of the main pond. This study aims to examine problems related to water and materials entering the mine. Based on the results of research using the calculation of the Gumbel distribution, through the Mononobe equation and rational formulas so that the runoff discharge is obtained where the total discharge that enters the washing pond is 710.81 m3/day. Thus, in order for the washing pond to optimally meet water needs, additional water is needed, which is 5,414.88 m3/day. To prevent silting of the main pond, periodic maintenance is needed, in this case the dredging of sedimentary material deposited in the pond. Based on the results of the study, it was found that 51,788 kg of solids were deposited in the pond carried by circulating water. With a reference of 60% of the pond capacity, the optimum time for dredging is once every 18 days. Pentingnya kebutuhan akan air menyebabkan air menjadi faktor utama dalam keberlangsungan kegiatan penambangan yang ada. Di samping itu, terjadinya pengendapan lumpur pada kolam utama menjadi permasalahan tersendiri yang sangat memungkinkan menyebabkan pendangkalan kolam utama. Penelitian ini bertujuan untuk meneliti permasalahan terkait air dan material yang masuk ke dalam tambang. Berdasarkan pada hasil penelitian yang menggunakan perhitungan distribusi Gumbel, melalui persamaan Mononobe serta rumus rasional sehingga didapatkan debit limpasan dengan total debit yang masuk ke dalam kolam pencucian sebesar 710,81 m3/hari. Dengan demikian, agar kolam pencucian dapat memenuhi kebutuhan air secara optimal, diperlukan air tambahan, yaitu sebesar 5.414,88 m3/hari. Untuk dapat mencegah pendangkalan kolam utama dibutuhkan perawatan berkala yang dalam hal ini adalah pengerukan material sedimen yang terendapkan di dalam kolam. Berdasarkan hasil kajian didapatkan sebanyak 51.788 kg padatan terendapkan di dalam kolam yang terbawa oleh air sirkulasi. Dengan acuan 60% kapasitas kolam, waktu optimum untuk dilakukan pengerukan adalah setiap 18 hari sekali.
Abstract. PT Nunukan Bara Santosa Satu (NBSS) is a private company owned by Medco Minning with commodities that produce coal, mining, processing and further marketing of coal commodities located in Sebakis Village, Nunukan District, Nunukan Regency, North Kalimantan Province, to support the mining process, at the Ambu site using a means of transportation with the Sany SKT 90 Dump Truck type with a Sany 750H digging tool, with the open pit open pit mining method, so that in all mining activities there are factors that are difficult to avoid, namely the weather, if it rains it will result in The cessation of production was due to the condition of the road being still soiled and the handling of the slipperly still lacking units, but this can be covered by sunny weather conditions. For this reason, this study has the aim of being able to analyze fleet macth for optimum productivity by minimizing obstacles that occur such as hauling roads that are not standardized by the Ministerial Decree No. 1827/K/30/MEM/2018, slipperly handling, road maintenance, front maintenance, truck queue which results in high cycle times that occur.The percentage of achievement of the productivity target based on the planned overburden stripping in July was 545,669 Bcm. Meanwhile, based on the actual results, only 222,276 BCM. The result is less than half of the plan that has been targeted. One of the causes of not achieving the production target is in the location preparation mechanism, lack of supervision, the number of breakdown units, the effect of site preparation and the effect of the compatibility of the number of equipment.From the observations in the field and the calculation of the compatibility factor between the excavator and the dumptruck, it was found that the MF result was 0.94 < 1, meaning that the excavator loading equipment worked less than 100% while the dumptruck transportation equipment worked 100%, so there was a waiting time for the loading equipment. Thus, if optimization is carried out on the effective work of the tool, evaluation of working hours and selection of healthy units can increase production results so that targets can be met. Abstrak. PT Nunukan Bara Santosa Satu (NBSS) adalah badan usaha swasta milik Medco Minning dengan komoditas yang penghasil batubara, kegiatan penambangan, pengolahan serta lebih lanjut melakukan pemasaran dari komoditas batubara yang terletak di Desa Sebakis, Kecamatan Nunukan, Kabupaten Nunukan, Provinsi Kalimantan Utara, untuk menunjang proses penambangan, pada site Ambu menggunakan alat angkut dengan jenis Dump Truck Sany SKT 90 dengan alat gali muat Sany 750H, dengan metode tambang terbuka open pit, sehingga dalam seluruh kegiatan penambangan terdapat faktor yang sulit untuk dihindari yaitu cuaca, jika terjadinya hujan akan mengakibatkan berhentinya produksi dikarenakan dengan kondisi jalan yang masih tanah serta dalam penanganan sliperly nya masih kekurangan unit, akan tetapi hal tersebut bisa ditutupi dengan kondisi cuaca yang cerah. Untuk itu penelitian ini memiliki tujuan agar dapat menganalisa fleet macth untuk productivity yang optimum dengan meminimalisir hambatan yang terjadi seperti jalan hauling yang kurang standar dengan peraturan Kepmen No.1827/K/30/MEM/2018, penanganan sliperly, road maintenance, front maintenance, truck queue yang mengakibatkan tingginya cycle time yang terjadi. Persentase ketercapaian target produktivitas berdasarkan rencana pengupasan lapisan tanah penutup (Overburden) pada bulan Juli sebesar 545.669 Bcm. Sedangkan berdasarkan hasil aktualnya hanya sebesar 222.276 BCM. Hasil tersebut kurang dari setengahnya dari rencana yang telah ditargetkan. Penyebab tidak tercapainya target produksi salah satunya yaitu dalam mekanisme penyiapan lokasi, kurangnya pengawasan, banyaknya unit yang breakdown, pengaruh penyiapan lokasi dan pengaruh keserasian jumlah alat. Dari hasil pengamatan di lapangan dan hasil perhitungan faktor keserasian antara excavator dan dumptruck didapat bahwa hasil MF sebesar 0,94 < 1, artinya alat muat excavator bekerja kurang dari 100% sedangkan alat angkut dumptruck bekerja 100%, sehingga terdapat waktu tunggu bagi alat muat. Dengan demikian jika dilakukan optimasi terhadap kerja efektif alat tersebut, evaluasi jam kerja dan pemilihan unit yang sehat dapat meningkatkan hasil produksi sehingga target dapat terpenuhi.
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