Integrating Ground Penetrating Radar, Induced Polarization and Aerial Photograph to Analyze Land Subsidence in Borehole Mining Operation Area: A Case Study from South Bangka Island

The remaining alluvial tin reserves around large ex-mining area can be an opportunity to optimize the potential reserves using a small-scale mining system. One of the latest breakthroughs in the mining system for the remaining alluvial tin reserves on land is the borehole mining (BHM) method. However, mining operations using BHM have several environmental impacts especially related to its former holes. This study aims to identify the changes in geometry of the former holes both on the surface and below the surface through direct field observations and measurements using geophysical methods. The study site is in the large ex-mining area of Air Nudur Block in South Bangka Regency, Bangka Belitung Islands Province. The geophysical methods used to identify the changes in the geometry of the BHM holes are GPR (ground penetrating radar) and IP (induced polarization). The GPR method has high resolution subsurface visual capabilities at shallow depths and this method can distinguish between stable and unstable layers. The IP method is used to determine the overburden layer and the condition of the alluvial layer where some of it has become a hole. These two methods will mutually reinforce in interpreting the change in the geometry of the BHM holes. Changes in hole diameter and depth were measured directly in the field within 2 (two) months from the completion of mining operations using the BHM method followed by the periodic topographic measurements using UAV (unmanned aerial vehicle). The results of observations on changes in the elevation of the ground surface around the former BHM hole indicated that the land level subsided by about 1 m. Meanwhile, the results of GPR data processing showed changes in the hole geometry with the hummocky radargram pattern into chaotic. Interpretation of IP data processing shows resistivity values of 250 - 1700 ohm.m and chargeability of 15 - 25 ms in the disturbed alluvial layer around the former BHM holes.

Sulfur Contamination and Environmental Effects: A Case Study of Current SO2 Industrial Emission by Biomonitoring and Regional Post-mining hot-spots

The presence of sulfur in the environment is an important macroelement for plant growth but becomes harmful in excessive amounts. The previous century saw rising levels of high SO2 concentrations (stemming from fossil fuel combustion) and wet deposition from acid rain, causing the intensification of forest die-back. Air pollution can be controlled or measured by biomonitoring. Despite recent reductions in SO2 emissions, urban and industrial areas are still at risk from high sulfur contamination. Open-cast lignite and sulfur borehole mining play a pivotal role in the regional scale of ecosystem contamination and acid mine drainage. Consequently, these aspects are unique for assessing the impact of extreme S contamination on soil properties changes, the vegetation effect, and biogeochemical cycles. We presented i) current SO2 pollution based on S concentration in pine needles, and ii) a comprehensive study of soil properties, as well as plant reactions to excessive sulfur concentration in the restored forest ecosystem of a former sulfur mine.

PENGELOLAAN LINGKUNGAN PADA KEGIATAN OPERASI TAMBANG DARAT BIJIH TIMAH MENGGUNAKAN METODE BOREHOLE MINING DI WIUP PT. TIMAH, TBK

ABSTRAK Borehole mining (BHM) merupakan metode penambangan menggunakan aliran air bertekanan tinggi (water jet) dan dikombinasikan dengan sistem pemompaan slurry dari bawah tanah. Dalam upaya meningkatkan produksi bijih timah, PT. TIMAH, Tbk melakukan kegiatan penambangan menggunakan metode BHM. Pemilihan metode penambangan BHM bertujuan untuk menambang sumberdaya marginal tanpa memerlukan stripping overburden (OB), dengan prinsip kerja: membuat lubang vertikal hingga dasar zona target menggunakan alat holemaker; dengan memanfaatkan tekanan water jet, air akan memberai material di sekelilingnya; saat material terberai, pompa tanah siap menghisap slurry hingga ke permukaan. Kapasitas penambangan efektif menggunakan metode BHM adalah 750 m3/bulan, dengan jam jalan efektif alat 125 jam/bulan. Kegiatan penambangan dengan metode BHM ini, berpotensi menimbulkan masalah lingkungan diantaranya terbentuknya lubang bekas penambangan (void) dan genangan air di sekitar lokasi tambang. Pemindahan tanah dari bawah permukaan pada kegiatan ore getting dengan volume 750 m3 dapat mengganggu struktur dan kekuatan tanah sehingga menyebabkan runtuhan/amblesan yang pada akhirnya menghasilkan void. Pengelolaan lingkungan yang tidak baik dapat menimbulkan masalah yang serius terhadap bentang lahan dan akan menimbulkan dampak turunan seperti masalah sosial. Perencanaan desain penutupan lahan dengan metode backfilling menjadi terobosan untuk mengatasi void yang ada. Prinsipnya, material yang akan diambil pada titik penambangan berikutnya ditransfer ke void sebelumnya yang telah terbentuk dan demikian seterusnya. Di samping itu, dilakukan revegetasi di sekitar lokasi penambangan BHM untuk meningkatkan daya dukung tanah. Limpasan air ke permukaan secara kontinu menyebabkan kondisi lahan sekitar menjadi lembab (jenuh air) sehingga daya dukung tanah menurun. Kegiatan penambangan menggunakan metode BHM di PT. TIMAH, Tbk memang merupakan suatu terobosan dalam konservasi cadangan bijih timah. Namun, aspek lingkungan juga menjadi hal yang perlu diperhatikan. Pengelolaan lingkungan yang tepat dapat meminimalkan masalah lingkungan yang terjadi. Lubang-lubang berdiameter 1,5 hingga 3 meter yang dihasilkan dapat diatasi dengan sistem back-filling. Limpasan air di permukaan diatasi dengan perencanaan sistem penirisan tambang yang terencana yaitu dengan pembuatan jalur/paritan di sekitar area penambangan. Kata kunci: borehole mining, void, backfilling ABSTRACT Borehole mining (BHM) is a mining method using high pressure water flow (water jet) and combined with an underground slurry pumping system. In an effort to increase tin ore production, PT. TIMAH, Tbk conducts mining activities using the BHM method. The selection of the BHM mining method aims to mine marginal resources without the need for stripping overburden (OB), with the working principle: making vertical holes to the bottom of the target zone using a holemaker; by utilizing the pressure of a water jet, water will fill the surrounding material; when the material is dispersed, the ground pump is ready to suction the slurry to the surface. The effective mining capacity using the BHM method is 750 m3 / month, with effective road hours of 125 hours / month. Mining activities using the BHM method have the potential to cause environmental problems including the forming of void pits and puddles around the mine site. Displacement of soil from below the surface in ore getting activities with a volume of 750 m3 can disrupt the structure and strength of the soil, causing collapse / subsidence which eventually produces voids. Improper environmental management can cause serious problems for the landscape and will cause derivative impacts such as social problems. Land cover design planning with backfilling method is a breakthrough to overcome existing voids. In principle, the material to be taken at the next mining point is transferred to the previously formed voids and so on. In addition, revegetation was carried out around the BHM mining location to increase the carrying capacity of the soil. The runoff of water to the surface continuously causes the surrounding land to become moist (saturated with water) so that the carrying capacity of the soil decreases. Mining activities use the BHM method at PT. TIMAH, Tbk is indeed a breakthrough in the conservation of tin ore reserves. However, environmental aspects also need to be considered. Proper environmental management can minimize environmental problems that occur. The holes with a diameter of 1.5 to 3 meters produced can be overcome with a back-filling system. Surface runoff is overcome by planning a planned mine drainage system by making a path / trench around the mining area Key Words: borehole mining, void, backfilling

UPAYA KONSERVASI MINERAL DAN PROYEKSI MASA DEPAN PERTAMBANGAN TIMAH DI INDONESIA

ABSTRAKKonservasi mineral dan batubara merupakan salah satu aspek yang diamanatkan oleh Undang-Undang Minerba untuk mewujudkan kaidah teknik pertambangan yang baik (Good Mining Practice). Konservasi minerba adalah upaya dalam rangka optimalisasi pengelolaan atau pemanfaatan sumber daya mineral dan batubara secara terukur, efisien, bertanggung jawab, dan berkelanjutan. Objek-objek yang menjadi target pengelolaan pelaksanaan konservasi mineral dan batubara sesuai Lampiran VII Kepmen ESDM No. 1827 K/30/MEM/2018 meliputi recovery penambangan, recovery pengolahan, batubara kualitas rendah, mineral kadar rendah, mineral Ikutan, sisa hasil pengolahan dan pemurnian, serta cadangan marginal. Kegiatan pertambangan timah di Indonesia berada di wilayah Provinsi Kepulauan Bangka Belitung dan Kepulauan Riau. Kegiatan ini dimulai sejak era kolonial Belanda yang ditandai dengan berdirinya "Banka Tin Winning Bedrijf" (BTW) di Belitung dan Singkep. Penambangan dilakukan oleh perusahaan swasta Belanda yaitu “Gemeeenschappelijke Mijnbouw Maatschappij Biliton” (GMB) dan “NV Singkep Tin Exploitatie Maatschappij” (NV SITEM). Kedua perusahaan ini berubah nama menjadi PT Timah, Tbk. Kegiatan pertambangan timah nasional mengalami pasang surut seiring dengan menipisnya cadangan timah karena eksploitasi yang sudah berlangsung lama dan perubahan terhadap kebutuhan saat ini maupun masa depan timah di dunia perindustrian. Untuk menjaga keberlanjutan kegiatan penambangannya, PT Timah, Tbk melakukan berbagai inisiatif diantaranya pelaksanaan konservasi dengan mengoptimalkan cadangan marginal, pemanfaatan sisa hasil pengolahan, penambangan mineral kadar rendah dan mineral ikutan. Saat ini PT Timah, Tbk mulai melakukan inventarisasi kembali cadangan timah yang sebelumnya ditinggalkan dan melakukan estimasi ulang untuk dikategorikan sebagai cadangan marginal. Potensi tambahan cadangan timah ini berasal dari bekas penambangan yang tidak tuntas maupun dari bekas penambangan tanpa ijin. Selain itu, PT. Timah, Tbk juga melakukan pendataan, inisiatif pengelolaan, dan rencana pemanfaatan untuk sisa hasil pengolahan, mineral kadar rendah dan mineral ikutan dengan aplikasi ketersedian teknologi saat ini. Beberapa upaya yang terus dikembangkan untuk tetap menjaga keberlanjutan industri pertambangan timah dan pengembangan timah primer adalah dengan pengembangan metode penambangan baru seperti borehole mining (BHM) dan inovasi metode penambangan yang sudah ada seperti cutter section dredges (CSD). Pelaksanaan hal-hal tersebut diatas adalah upaya nyata yang dilakukan oleh PT Timah, Tbk untuk melaksanakan konservasi mineral dan mendorong terwujudnya kaidah teknik pertambangan yang baik. Dengan pelaksanaan konservasi mineral dan dukungan dari seluruh stackholder, baik Pemerintah Daerah Provinsi Kepulauan Bangka Belitung dan PT. Timah, Tbk maka diproyeksikan kegiatan pertambangan timah nasional dapat terus bertahan dan berkelanjutan untuk menunjang industri timah nasional.Kata Kunci: konservasi minerba, timah, cadangan marginal, sisa hasil pengolahan, mineral kadar rendah, mineral ikutan, pengelolaanABSTRACTMineral and coal conservation is one of the aspects mandated by the Minerba Regulation to embodies the principles of Good Mining Practice. Mineral and coal conservation is an effort to optimize the management or utilization of mineral and coal resources in a measured, efficient, responsible and sustainable. Objects that are targeted for mineral and coal conservation in accordance with Attachment VII of the Minister of Energy and Mineral Resources Decree No. 1827 K / 30 / MEM / 2018 comprise of restoration mining recovery, processing recovery, low quality coal, low grade minerals, gangue minerals, residues from processing and refining, and marginal reserves. Tin mining activities in Indonesia are mainly in the provinces of the Bangka Belitung Islands and Riau Islands. This activity began in the Dutch colonial era marked by the establishment of "Banka Tin Winning Bedrijf" (BTW) in Belitung and Singkep. Mining is carried out by a Dutch private company, "Gemeeenschappelijke Mijnbouw Maatschappij Biliton" (GMB) and "NV Singkep Tin Exploitatie Maatschappij" (NV SITEM). These two companies then merged into PT Timah, Tbk. Tin mining activities in Indonesia experienced the ups and downs through the depletion of tin reserve due to lifelong exploitation and changes in the current needs and the future of tin in the industrial world. To ensure the sustainability of its mining activities, PT Timah, Tbk has conducted a variety of initiatives such as conserving by optimizing marginal reserve, utilizing the residue of processed products, mining low grade minerals and accompanying gangue minerals. Currently PT Timah, Tbk starts to carry out an inventory of the previously abandoned reserves and re-estimates to be categorized as marginal reserves. This potential additional on tin reserves are comes from mines that are incomplete or from ex-mining activity without permits. In addition, PT. Timah, Tbk also conducts data collection, management innitative, and utilization plans for processing residues, low grade minerals and gangue minerals with current technology applications available. Some efforts that are continually being developed for the sustainable development of the tin mining industry and primary tin development are by developing new mining methods such as borehole mining (BHM) and innovate in existing mining methods such as cutter section dredges (CSD). The implementation of the above is a real effort made by PT Timah, Tbk to carry out mineral conservation and encourage the realization of good mining practice. With mineral conservation and the support from the stockholders, the Bangka Belitung Islands Provincial Government and PT. Timah, Tbk, it is projected that tin mining activities in Indonesia can be maintained and sustainable to support the national tin industry.Key Word: Coal and mineral Conservation minerba, tin, marginal reserve, residual of processing and refining, Low grade mineral, gangue mineral,management

Increasing of filtration characteristics of ore bodies in borehole uranium mining

There is a description of technology by borehole uranium mining in Kazakhstan. The factors which affect for reduction of filtration characteristics in productive reservoirs are studied in detail and described an effective method for increasing borehole uranium production. The processes that occur during borehole mining of uranium with the use of sulfuric acid as solvent, as well as the conditions and reasons for reducing the productivity of geotechnical wells during their operation are considered. The results of experimental work on the intensification of borehole uranium mining in complex mining and geological conditions are analyzed and discussed, comparative graphs of the content of uranium in the productive solution, the flow rate of wells, the degree of extraction and the volume of production before and after the experiments are constructed. The results of experimental work on the efficiency of borehole uranium production, the content of uranium in PS and the productivity of wells, with predominance of the chemical type of sedimentation, are positively evaluated. The optimal parameters for the intensification of borehole uranium production in complex mining and geological conditions are recommended, and method for using complex of multi-purpose chemical reagents in combination with traditional methods of well regeneration is developed.

Hydraulic borehole mining method possible application at Middle Larba alluvial gold field

Gold on placer deposits is mainly extracted in two ways: open and underground. But the open method of mining has a great negative impact on the environment, and the mine method is characterized by high labor intensity, capital and operating costs. As an alternative to these methods of development of alluvial gold, the hydraulic borehole mining method can be used. The use of a well as a hydro-mining creates favorable opportunities for ensuring nature protection and safe operation. When applying the method, the well does not have hydraulic extractions: stripping, this allows preserving the cultural layer of the soil in its integrity; explosive, loading works and use of motor transport, excluding dustiness and gas pollution of the atmosphere; the hard and harmful work for people's health is eliminated. The method of well drilling requires further serious scientific, technical and developmental studies to increase its reliability and expand the field of application. Alluvial deposits of gold are the most favorable objects for hydraulic borehole mining under their mining and geological conditions. Recently, new gold placers have been identified and are being surveyed at a depth of more than 40 m. With a high content of metal in them, these placers are very promising for mining by the hydraulic borehole mining method. The reserves of gold in these fields reach several tens of tons. Against the backdrop of a reduction in inventories for open and underwater mining, large technical difficulties, significant capital investments and operating costs for underground mining of thawed buried placers, the advantages for gold mining by the hydraulic borehole mining method are increasing. Based on mentioned above, the study of the application of the hydraulic borehole mining method in the conditions of Siberia and the Far East is a timely scientific task.

Expanding of spheres the application of borehole hydro-production technology to develop deposits of non-traditional hydrocarbons

The reserves of oceanic hydrates of methane and natural bitumen in times exceed the stocks of traditional oil and gas. The purpose is the analysis of the adaptation possibility of borehole mining technology for the development of bituminous sands deposits and marine gas hydrates was the purpose of the study. The variants of the HBM technology adaptation for the development of bituminous sands and gas hydrates deposits are proposed. The method of extracting gas hydrates based on HBM technology involves them removal without the energy consumption for phase transition. The main advantages of the development of bituminous sands deposits on the basis of HBM technology are: the possibility them extraction in the range of depths 75 – 200 m, the potential high rate of bitumen extraction, the separation of bitumen from the rock in production, the minimum impact on the environment, the possibility of conducting extraction of natural bitumen in areas covered with water.