Judul: Analysis of Development of Post-Coal Mining Land Reclamation Research in Indonesia
Abstrak: Pertambangan merupakan salah satu sektor yang dapat menyumbangkan devisa besar bagi negara. Komoditas pertambangan di Indonesia diklasifikasikan menjadi mineral, batu bara, serta minyak dan gas. Batu bara di Indonesia umumnya diekstrak dengan sistem penambangan terbuka yang menghilangkan ekosistem hutan beserta fungsinya. Kegiatan tersebut menyebabkan terbentuknya lahan terdegradasi sehingga dibutuhkan penerapan kegiatan revegetasi. Penelitian ini bertujuan untuk mengetahui perkembangan penelitian untuk mendukung keberhasilan reklamasi tambang batu bara di Indonesia serta mengetahui kategori penelitian yang kurang mendapat perhatian dan perlu pengembangan lebih lanjut. Penelitian dilakukan dengan mengumpulkan semua informasi yang tersedia secara online berasal dari jurnal, repository, buku dan sumber yang terkait dengan kegiatan reklamasi lahan bekas tambang batu bara. Berdasarkan hasil penelitian, kategori yang paling banyak diteliti adalah kategori kualitas tanah dan kategori pemilihan jenis tanaman dengan masing-masing 23 judul penelitian, sedangkan kategori persemaian yang paling sedikit diteliti, yaitu hanya 2 (dua) judul penelitian. Kata kunci: batu bara, jenis tanaman, reklamasi, tanah tambang, Mining is one of the sectors that can contribute large foreign exchange for the country. Mining commodities in Indonesia are classified into minerals, coal, and oil and gas. Coal in Indonesia is generally extracted by an open-pit mining system which eliminates forest ecosystems and their functions. These activities lead to the formation of degraded land so that the implementation of revegetation activities is needed. This study aims to determine the development of research to support the success of coal mine reclamation in Indonesia and to find out aspects of research that have received less attention and need further development. The research was conducted by collecting all the information available online from journals, repositories, books and sources related to land reclamation activities of former coal mines. Based on the results of the research, the most studied categories were the soil quality category and the plant species selection category with 23 research titles each, while the nursery aspect was the least studied, namely only 2 (two) research titles. Keywords: coal, mining land, reclamation, types of plants
Keyword: batu bara, jenis tanaman, reklamasi, tanah tambang, coal, mining land, reclamation, types of plants

Judul: Quality Analysis of River Water Around and Soil in the Mining Area of PT Berau Coal Binungan Site, East Kalimantan Province
Abstrak: Salah satu hal terpenting dalam aktivitas penambangan batubara dengan sistem tambang terbuka adalah bagaimana melakukan reklamasi lahan dan mengembalikan agar kelestarian lingkungan tetap terjaga. Reklamasi lahan pasca tambang merupakan bagian dari perencanaan dan pelaksanaan kegiatan penambangan untuk memastikan agar upaya perbaikan lahan-lahan yang terganggu oleh kegiatan pertambangan dapat dilaksanakan secara efektif dan efisien dengan mempertimbangkan karakteristik kondisi fisik, kimia, dan biologi tanah. Sampai saat ini reklamasi yang telah dilakukan diduga belum ada yang berpihak pada pembangunan kawasan pasca tambang batubara yang berkelanjutan dengan menganut prinsip memanfaatkan, melindungi dan melestarikan lingkungan. Sementara itu, pelaksanaan reklamasi yang dilakukan sampai saat ini sifatnya sekedar memenuhi tuntutan prosedur yaitu hanya menjadikan reklamasi sebagai bagian dari persyaratan pelaksanaan pertambangan batubara yang kebanyakan belum memadai. Kegiatan reklamasi ini selain ditunjukan untuk memperbaiki sifat-sifat tanah, diharapkan juga akan memperbaiki kualitas air permukaan di sekitar areal reklamasi. Oleh karena itu perlu dilakukan penelitian untuk mengetahui kondisi air dan tanah di sekitar areal daerah tersebut. Dengan penelitian ini, diharapkan menjadi acuan dalam pelaksanaan reklamasi yang berkelanjutan., Coal mining activities without reclamation will lead to environmental degradation such as change of freshwater and soil qualities. Reclamation of post mining land is part of the planning and implementation of mining activities to ensure that repairing of lands affected by mining activities can be conducted effectively and efficiently by improving the post mined soil conditions. This research was aimed to analyze the qualities of river water around and soil in the mining area of PT Berau Coal Binungan Site. Samples of river water were taken as many as 10 locations, whereas soil samples were taken from soils of land after 0, 3, 6, and 9 years of reclamation and forest soil. The results showed that some of the parameters of water such as temperature, pH, DO, Fe, Mn, oils and fats, were below the grade I Quality Standard of Government Regulation No. 82/ 2001. However, COD was above Grade III, while BOD was above grade IV of the Quality Standard. These indicates that all the water sample were not qualified as standart drinking water (grade I). Results of soil analysis indicated that physical, chemical and biological of soil properties varied both due to the increase in reclamation age and the heterogeneous nature of the soil materials. Properties including BD, infiltration, aggregate stability, organic-C, and biological properties were improved with increasing the age of reclamation approaching the properties of forest soil. Other properties including pH, CEC, exchangeable bases, base saturation, available P, available micro elements, and total S were varied due also to the heterogeneous nature of the soil material.
Keyword: Coal mining, Water quality, Soil quality

Judul: Penggunaan Teorema Homeomorphy 2-Manifold dan Teorema Euler Poincare pada Torus 𝑇�� dan Simplicial Complex 𝐾��
Abstrak: Two dimensional topological spaces are said to be homeomorphic if they have the same topological invariant, where one of topological invariant used is an Euler characteristic. Homeomorphy 2-Manifold’s Theorem and Euler Poincare’s Theorem are used to distinguish two topological spaces. Homeomorphy 2-Manifold’s Theorem uses Euler characteristic to identify two dimensional topological spaces. Euler Poincare’s Theorem is an alternative way to find Euler characteristic with Betti number, which is topological invariant as well. The objective of this paper is to investigate the homeomorphism of torus 𝑇����� and simplicial complex 𝐾�����. Topological space torus and simplicial complex 𝐾����� have the same Euler characteristic, which is two. Based on Homeomorphy 2-Manifold’s Theorem topological space torus 𝑇����� and simplicial complex 𝐾����� is homeomorphic.
Keyword: simplicial, torus, Euler, homeomorphism, topology