Coal combustion produt (CCP) from Banjarsari power plant, both fly ash and bottom ash are numerous and have not been utilized optimally. CCP contains rare earth elements so that the potential needs to be assessed as a resource and reserve of rare earth elements (REE) in the future. The stages of this research were sample preparation and testing of grain size distribution using the wet and dry sieving method. Grain morphology was observed under a microscope and the determination of mineralogical content with XRD, oxide content with XRF and elemental content with ICP-MS. Fly ash grain size distribution of 76.15% passed 200 mesh sieve (0.074 mm) while the bottom ash was only 0.2%. Grain morphology is sub-rounded and there are still coal that has not been completely burned. The dominant mineral content is quartz, mica mineral (muscovite), clay mineral (kaolinite), lime, siderite, magnetite and hematite. The dominant oxides are SiO2, Al2O3, Fe2O3 and CaO. Based on ICP-MS test results, 16 elements of REE were detected. The total REE contents for each sample, FA and BA were 264.97 ppm and 49.22 ppm, respectively. REE of CCP from Banjarsari power plant which has the potential to be extracted is the content of cerium 80.5 ppm, neodymium 42.9 ppm, yttrium 41.8 ppm and lanthanum 31.4 ppm from fly ash while at the bottom ash there is no potential to be extracted.

Nikel laterit adalah produk residual pelapukan kimia pada batuan ultrabasa. Pelapukan pada peridotit menyebabkan unsur-unsur dengan mobilitas rendah sampai immobile seperti Ni, Fe dan Co mengalami pengayaan secara residual dan sekunder. Pulau Obi merupakan salah satu daerah yang dianggap prospek terhadap endapan nikel laterit terutama di Pulau Obi bagian Utara. Kandungan logam Ni (nikel), Fe (besi), dan Co (kobal), di daerah ini merupakan hasil pelapukan dari dunit. Penelitian ini melakukan pengkajian lebih spesifik mengenai penyebaran endapan nikel laterit khususnya di Pulau Obi, Kabupaten Halmahera Selatan, Propinsi Maluku Utara. Litologi daerah penelitian disusun oleh konglomerat, diorit dan dunit. Profil endapan nikel laterit daerah penelitian terdiri atas zona limonit, saprolit dan bedrock. Ketebalan zona limonit bervariasi dari 1 - 5 meter. Ketebalan zona saprolit mencapai 16 meter. Berdasarkan penelitian dapat disimpulkan bahwa profil geokimia di daerah penelitian menujukan terjadinya ketidak normalan distribusi unsur-unsur yang ada, baik unsur Ni, Co, Fe, SiO2, CaO dan MgO. Selain itu, ketebalan dan kedalaman endapan nikel laterit dapat bervariasi. Oleh karena itu perlu dilakukan penelitian yang lebih mendalam lagi mengenai penyebaran endapan nikel laterit karena setiap lokasi memiliki karakteristik yang berbeda.

Acid Mine Drainage (AMD) is one of environmental concerns of mining activities and need to be prevented. One of AMD prevention method is passive method by blending PAF Material with Non-Acid Forming Material. One of constraint often faced by mining companies is the limitation of NAF material. Other Non-Acid Forming Material that is available and abundant near mine site is fly ash from Mine-Mouth Coal-Fired Power Plant Banjarsari. The Study of usage of fly ash as a blending material with PAF material in order to prevent AMD is deemed necessary. Different blending simulations of varying PAF material size (fine and coarse) and varying fly ash-PAF Material ratio (2:1; 1:1; and 0,5:1 by weight) are made and leachate water from kinetic test is physically and chemically tested. This study result shows that variation in OB-Claystone grain size is not influencing the acidity of leachate water. Blending FA with OB-CS with minimum ratio of 1,12:1 (by weight) is effective to prevent AMD generation. Acid-base equilibrium is met when ratio of mole-transfer between neutralizing mineral (periclase, lime and gypsum) to acid-generating mineral (pyrite) is 1:1 (by weight). The higher ratio of FA in blending, the lower oxidation and alkalinity-production rate. Rate of oxidation of pyrite and alkalinity-production rate is the same at OB-CS and FA blending ratio of 1:1,62 (by weight).

Nikel laterit adalah produk residual pelapukan kimia pada batuan ultrabasa. Proses ini berlangsung selama jutaan tahun dimulai ketika batuan ultrabasa tersingkap di permukaan bumi. Pelapukan pada peridotit menyebabkan unsur-unsur dengan mobilitas rendah sampai immobile seperti Ni, Fe dan Co mengalami pengkayaan secara residual dan sekunder. Penelitian ini bertujuan untuk mengetahui karakteristik geokimia endapan nikel laterit di daerah Pulau Obi. Kandungan unsur dan oksida ditentukan dengan analisis XRF. Kondisi morfologi, lithologi serta struktur lokal dapat mempengaruhi pola penyebaran unsur pada profil geokimia seperti pembentukan rekahan pada batuan dasar. Hal ini akan mempengaruhi tingkat pelapukan dan pengkayaan serta distribusi unsur Ni, Fe, Co, oksida SiO2, CaO dan MgO, berdasarkan hasil analisis petrografi. Pada profil laterit, zona laterisasi seperti limonit, saprolit dan bedrock.