Earthquake Relocation Studies near Local Scale Sources using Double-Difference Technique

Determination of the location of the hypocenter is very necessary to monitor the potential for seismic hazard. Positioning and seismic energy can help safety workers determine which areas can be mined or temporarily halted. Earthquakes in underground mines are caused by seismic induction due to mining activities such as blasting processes, hydrofracturing, vehicle activities, etc. Earthquakes that occur are generally clustering. Earthquake events generally occur in mine openings, this is caused by mass compensation taken. The data used in this study are synthetic micro-earthquake data around the mining area. To obtain a high level of accuracy and precision, especially in determining the location and depth in determining the hypocenter using the Double-Difference (DD) method. The results of the microseismic relocation in the study area are well covered, as evidenced by the residual histogram and shift distribution. The shift of the microseismic before and after being relocated spread in all directions with the dominant direction in the NE – SW direction. The value of the microseismic shift before and after being relocated ranged from 0.5 meters to 150 meters.

The planning of mine drainage system at PT Perkasa Inakakerta, East Kutai Regency

This research located in Beruang Block Kalimantan. The purpose of the mine drainage planning system is to control runoff water. Therefore, an excellent drainage system is needed without interfering with mining activities such as runoff water pollution, which could cause contamination in the surrounding area and outside the mining sites. Based on the analysis of rainfall data of 2009-2020, the precipitation plan was 341.67 mm/day; the concentration time was 2.37 h, the rain intensity was 41.06 mm/h, and repeated rain periods were 2-years. The extensive catchment area was 1.52 km2 because the runoff entering the sump was 44.38 m3/h. To prevent the water from entering the mining area, an open channel was made around the mine openings, and the water flows naturally into the sump. The water pumped into the settling pond with the pump type Allight HL 150MHD-IT at 50 m/s for 3-days with a single rain, resulting in total water volume of 17,556.5 m3/day. A trapezoidal shape was designed for a sump with dimensions of 3.96 m in length and width at the surface, 1.79 m length and width at the base, and 1.03 depth.

PENGELOLAAN AIR DALAM MENUNJANG KEGIATAN PENCUCIAN PADA PROSES PENAMBANGAN BAUKSIT

ABSTRAK Dalam melaksanakan kegiatan ekspor bauksit, sesuai Permen ESDM nomor 25 tahun 2018, perusahaan tambang diwajibkan untuk melakukan peningkatan kadar bauksit yang akan dijual melalui proses pencucian. Untuk mendukung hal tersebut, dibangun washing plant, sebagai sarana proses pencucian, dan sedimen pond, sebagai sarana sumber air serta pengelolaan limbah. Secara umum, proses pengelolaan air berawal dari run off pada bukaan tambang, yang dikelola dengan membuat kolam pengendapan di area tambang. kemudian untuk mendukung proses pencucian, dibangun sedimen pond sebagai sarana tempat penampungan limbah hasil pencucian dan pengelolaan air limbah sehingga dapat digunakan kembali untuk proses pencucian bauksit di washing plant. Alur proses pencucian berawal dari air pada kolam dipompakan ke washing plant, limbah hasil pencucian dialirkan ke kolam sedimen, kemudian dilakukan proses daur ulang melalui sirkulasi tertutup dengan dialirkannya kembali air tersebut ke kolam pompa untuk digunakan pada proses pencucian. Pada musim hujan, apabila terdapat penambahan air dari run off, sebagian air dialirkan ke badan air atau lingkungan untuk menjaga kapasitas tampung dari kolam sedimen. Dikarenakan adanya aliran air ke lingkungan, maka Tambang Bauksit Tayan wajib memenuhi persyaratan pada Peraturan Menteri Lingkungan Hidup nomor 34 tahun 2009 tentang Baku Mutu Limbah Air Kegiatan Pertambangan Bauksit. Berdasarkan peraturan tersebut, Tambang Bauksit Tayan wajib memenuhi kadar baku mutu pH di rentang 6-9 dan maksimum kadar Total Suspended Solid (TSS) 200 mg/l. Maka dari itu, sebelum dialirkan ke kolam pompa, dilakukan penambahan flokulan untuk menjaga kadar TSS air tidak melebihi baku mutu sehingga diperbolehkan untuk dialirkan ke lingkungan dan mengondisikan air tetap jernih untuk menunjang proses pencucian. Untuk mengetahui flokulan dengan kinerja paling optimal, dilakukan jar test dengan beberapa jenis flokulan untuk mengetahui perbandingan biaya terhadap efektivitas proses yang dihasilkan. Dari percobaan yang dilakukan, seluruh flokulan efektif dan diperoleh efisiensi proses tertinggi dari flokulan sebesar 99% untuk konsentrasi flokulan uji 5 ppm. Kemudian flokulan tersebut digunakan sebagai bahan penjernih air pada water treatment plant untuk mengelola air limbah pencucian bauksit agar sesuai dengan standar parameter yang tertera pada regulasi yang ada. Dengan dilaksanakannya proses pengelolaan run off pada bukaan tambang, pengelolaan sedimen pond, dan pemenuhan aspek kepatuhan regulasi, kegiatan penambangan bauksit, khususnya pada tahapan pencucian di washing plant dapat dilaksanakan secara optimal sehingga dapat mendukung proses produksi untuk mencapai target yang telah ditetapkan. Kata Kunci : Run Off, Pencucian Bauksit, Sedimen Pond, Total Suspended Solid, Flokulan ABSTRACT In carrying out bauxite export activities, according to Minister of Energy and Mineral Resources Regulation No. 25 2018, mining companies are required to increase the level of bauxite which will be sold through the washing process. To support this, a washing plant was built, as a means of the washing process, and a sediment pond, as an air source and waste management. In general, the process of water management starts from runoff at mine openings, which is managed by creating a settling pond in the mine area. then to support the washing process, build a sediment pond as a waste disposal place for washing and waste water management can be used again for the process of washing bauxite in the washing plant. The flow of the washing process starts from the water in the pond being pumped to the washing plant, the washing wastes are channeled into the sediment pond, then the recycling process is carried out through closed circulation by being channeled back into the pump pond for use in the washing process. In the rainy season, it needs air assistance from runoff, most of it is channeled to the air bodies or the environment for the reserve capacity of the sediment ponds. Due to the flow of water into the environment, the Tayan Bauxite Mine is required to meet the requirements of the Minister of Environment Regulation No. 34/2009 concerning Quality Standards for Wastewater in Bauxite Mining Activities. Based on these regulations, the Tayan Bauxite Mine is required to meet pH quality standards in the range of 6-9 and a maximum level of Total Suspended Solid (TSS) of 200 mg / l. Therefore, before flowing into the pump pond, do flocculant to get TSS levels of air not exceeding the quality standard so that it is diverted to the environment and condition the air to remain clear to support the washing process. To find out the flocculant with the most optimal performance, do a jar test with several types of flocculant to find out the costs for the resulting process. From the experiments, all the effective flocculants and the highest process efficiency obtained from flocculants was 99% for the 5 ppm flocculant concentration test. Then this flocculant is used as an air purifier in water treatment plants to manage bauxite washing wastewater to comply with the standard parameters stated in the existing arrangements. By carrying out runoff management processes at mine openings, pond sediment management, and compliance with regulatory aspects, bauxite mining activities, particularly at the washing stage at the washing plant can be carried out optimally, can support the production process to achieve the targets. Keywords: Run Off, Bauxite Washing, Sediment Pond, Total Suspended Solid, Flocculant

Substantiation of the possibility of developing reserves of the Third potash horizon of the Starobin deposit, previously worked out by the chamber system

A technique has been developed of justification of possibility and expediency of extraction of the reserves left, which were mined more than 40 years ago by chamber system with maintenance in a safe condition of underground mining constructions. The methodology includes the identification by studying the geological and mine surveying documentation of districts with reserves in the mine fields; calculation of volumes and quality indicators of reserves left at these areas; assessment of a condition of mine workings that have direct access to the reserves concerned, and the possibility of their re-use, as well as the possibility of new development workings and ensuring their sustainability and maintenance in a safe condition; establishing the features of geomechanical processes in the rock mass and the presence of dangerous violations in the worked-out zone, the degree of the violation and the nature of the deformation of rigid and pliable pillars in the extraction chambers, including the use of specially conducted mine openings; development of technological schemes for safety extraction of abandoned minerals. With the use of this technique for the first time the technological opportunities and economic feasibility of mining minerals from the treatment units of the First and Second Mines of JSC Belaruskali, worked out more than 40 years ago, has been estimated. The possibility of excavating abandoned reserves in the sylvinite layer 4 and layers 2, 2–3, 3 in inter-chamber pillars in areas previously worked out by the chamber system with total volumes of more than 57 million tons is shown. The results of surveys of the state of capital and development workings are given, according to which for the re-mining of most of the worked-out blocks, new capital and development workings will be required. The results of visual examinations of panel and block drifts, their conjugations with treatment passages, as well as the state and degree of violation of inter-passage and inter-chamber pillars in the treatment chambers are described. Possible methods for re-mining the reserves of the Third potash horizon with treatment longwalls and a chamber system are proposed, which are distinguished by high technical and economic efficiency and mining safety.