Geo-mechanics and Hydraulic Conductivity Study of Claystone in Boyolali, Central Java, Indonesia

Claystone middle Miocene age were found in Wonosegoro sub-district, Boyolali region, Central Java, Indonesia. The purpose of the paper is to examine and discuss the geology and typical behavor of this claystone and its micro-level mechanism. The hydraulic conductivity was assessed using consilidated apparatuses; 150 mm diameter column mound using aggregated sample and 60 mm oedometer mould using slurry sample as a reference. Claystone materials used were treated under various conditions. In long term test under constand vertical stress and hydraulic gradient, the hydraulic conductvity decreases with time although the volume of void volume of the sample increased by swelling. Water contens of the individul aggregated increased by swelling, by which strength of particles decreases with and aggregate breakdown was enchanced. As a result, large void created by large particles could be redused in its size, leading the reduction of hydraulic conductuvity. The hydralic conductivities (K values) obtained from the aggregated sample varied in a broad range compared with those from slurry sample. In the test using the higher percentage of gravel-sized aggregate (up until couarse gravel-sized; retained in 26.5 mm sieve), K values changed from 10-5 to 10-7 m/s under vertical stresses from 5 up to 245 kPa. The test was repeated using smaller percentage of gravel-sized aggregate (up until fine gravel-sized, retained in 4.75 mm sieve) and the observed K values changed from 10-5 to 10-10 m/s. While the K values obtained in the specimen made from surry under same vertical stresses was 10-9 to 10-11 m/s. All of the extruded aggregate samples had higher water content than the initial ones, which suggest the alteration mechanism of soled consolidation phase to more deformable plastic phase, whice enables thesample to decrease the void size. These results conclude that using coarse gravel-sized aggregated, which is a reasonable scenario of a practically feasible aggregate size in a field, may noy produce the aimed hydraulic conductivity by the regulated standard. Therefore, breakdown of the aggrgate size and enchament of swelling are crucial factors for the application of the clay stones as a barrier material

Stabilisasi merkuri pada limbah tambang dengan menggunakan zeolit alam

Mercury contamination caused by artisanal gold mining waste would become an environmental problem if there were no remediation actions. This study aimed to investigate the ability of natural zeolite obtained from Gunungkidul Yogyakarta to stabilize mercury in mining waste or tailing. Tailing samples were obtained from three locations on Kulon Progo, Wonogiri, and Banyumas, and the natural zeolite sample was obtained from Gunungkidul, Yogyakarta. The batch experimental study was conducted to test the ability of the effectiveness of natural zeolite in stabilizing mercury in tailing. The result of the study shows that the natural zeolite used in the experimental study can be used to reduce the mercury concentration in tailing. The natural zeolite's ability for stabilization varies and depends on the initial mercury concentration in tailing and the natural zeolite dose.Pencemaran merkuri yang disebabkan oleh limbah tambang emas tradisional menjadi salah satu masalah lingkungan yang berdampak serius jika tidak dilakukan penangangan. Penelitian ini bertujuan untuk menginvestigasi kemampuan zeolit alam yang diperoleh dari Gunungkidul Yogyakarta untuk menstabilisasi merkuri yang terdapat pada limbah tambang emas tradisional atau tailing. Sampel tailing diambil dari tiga lokasi di Kulon Progo, Wonogiri dan Banyumas, sedangkan sampel zeolit alam diambil dari Gunungkidul, Yogyakarta.  Percobaan batch dilakukan pada skala laboratorium untuk menguji efektifitas zeolit alam dalam menstabilisasi merkuri dalam tailing. Hasil penelitian menunjukkan bahwa zeolit alam yang digunakan dapat menurunkan konsentrasi merkuri dalam tailing. Kemampuan stabilisasi yang dimiliki oleh zeolit bervariasi tergantung pada konsentrasi awal merkuri pada tailing dan dosis zeolit alam yang ditambahkan.&nbsp

Implementasi Sistem Manajemen Hot Work ke dalam Sistem Manajemen Keselamatan dan Kesehatan Kerja

The Occupational Safety and Health Management System (SMK3) is part of the company's management system in general which aims to control risks associated with work activities in order to create a safe, efficient and productive work environment. PP RI Number 50 of 2012 issued regulations regarding the Implementation of the Occupational Safety and Health Regulatory System, and Article 5 of the Law requires every company to implement SPK3 in their company, especially for companies that employ a minimum of 100 (one hundred) workers/laborers or have a high level of potential hazard. Hot work Permit System is a system of written permission to do work that generates heat sources. This study aims to determine the implementation of SMK3 with hot work system management as fire and explosion prevention at PT. XYZ, Indramayu. It is recommended for companies to strengthen the application of safety culture by implementing a hot work permit system, organizing training for welding workers, and conducting socialization regarding standard operating procedures (SOP) in work behavior for all workers

Ball-milling effect on Indonesian natural bentonite for manganese removal from acid mine drainage

The influences of mechanical milling on Indonesian Natural Bentonite (INB) characteristics and manganese (Mn) removal from acid mine drainage (AMD) were investigated. The INB characteristics were observed by scanning electron microscope (SEM), X-ray diffraction (XRD), nitrogen adsorption-desorption for specific surface area (SSA) and microporosity measurement, cation exchange capacity (CEC) and particle size distribution (PSD) analyzer. Four minutes milling with frequency 20 Hz on INB caused morphological change which showed more crumbled and destructed particle, lost the (001) peak but still retained the (100) peak that indicated delamination of montmorillonite mineral without breaking the tetrahedral-octahedral-tetrahedral (T-O-T) structure, rose the CEC from 28.49 meq/100g to 35.51 meq/100g, increase in the SSA from 60.63 m2/g to 104.88 m2/g, significant increase in microporosity which described in the t plots and decrease in the mean particle size distribution peak from 49.28 μm to 38.84 μm. The effect of contact time and effect of adsorbent dosage on Mn sorption was studied. Both unmilled and milled samples reached equilibrium at 24 hours and the pH rose from 4 to 7 in first 30 minutes. The Mn removal percentage increased significantly after milling. Using Langmuir isotherm, the maximum adsorbed metals (qmax) also increased from 0.570 to 4.219 mg/g