Dear Riset IJGM Readers,

Our privilege to present the first edition of Volume 32 of Riset Geologi dan Pertambangan, Indonesian Journal of Geology and Mining (Riset IJGM). Our journal publishes high-quality research papers in geology, mining, applied geophysics, and related topics on earth science. All articles have been peer-reviewed by experts prior to publication.

This edition includes five articles. In the first paper, Adimedha et al. explains characteristics of Thorium-bearing minerals using Micro-XRF in metamorphic rocks in Harau, West Sumatra. They report that Thorium-bearing minerals found in the study area are of thorite (ThSiO₄), yttrialite (YThSi₂O₇), and monazite ((Ce,Nd,Th)PO₄) with thorium levels within 2.75 - 42.75% ThO2 but experiencing a significant increase in Fe. The second paper by Wahab et al. describe their finding on the effect of temperature, acid concentration, and leaching time on nickel extraction percentage and the leaching kinetics. They conclude that diffusion through the unreacted solid product layer controls the nickel leaching rate. The following article elucidates a review on synthetic and earth’s resource-based slow-release fertilizers and their potential role in reducing groundwater pollution. These authors (Dida et al.) suggest two particular minerals that can be used as raw materials in slow-release fertilizer synthesis: hydrothermal silica and obsidian. XRD analysis of these two materials shows the presence of amorphous silica and other minerals. Thus, silica in compacted slow-release fertilizer can control the release rate of nutrient elements from fertilizer. The fourth paper by Putra et al. reports their results of individual debris flows modelling based on DEMNAS using Flow-R. This study took place in in Sigi, Central Sulawesi, where the Mw 7.5 devastated the Palu region in Central Sulawesi, resulting a catastrophic disaster and many casualties. Their quantitative analysis assess the accuracy, positive predictive value, and negative predictive value of their resulted models. In the last paper, Widiatama et al. report their finding on the ichnofossils characteristics in pelagic and siliciclastic carbonate turbidites of Weda Formation in Halmahera Island. This article describes three facies association within a submarine fan deposit, and further discusses relation between the distribution of the ichnofossils and submarine depositional model.

We acknowledge the editors for their continuous supports to Riset IJGM. Riset IJGM would not have been successful without your outstanding support and dedicated work. We sincerely acknowledge the outstanding reviewers who support reviewing the articles submitted to our journal and all the authors for their valuable contributions to this volume of Riset IJGM.