In underground coal mines, coal pillars play a major rule in sustaining the weight of the overburden and protecting the stability of the entries and crosscut during mine development and production, allowing the miners to safely extract the coal¹. The determination of a coal pillar size is adjusted to the expected load and strength of the coal seam. It needs to consider several factors such as pillar load (stress within the pillar), pillar strength, and safety factors. In this determination, an analysis will be conducted using five similar coal pillar strengths including; Obert-Duvall Equation (1967), Holland Equation (1964), Holland-Gaddy Equation (1956), Salamon-Munro Equation (1967), and Bieniawski (1983). Using AirLaya seam as an example, we can combine the results of various equations. The coal used in the Airlaya research area has a value of k = 425.75, thus the strength of Airlaya insitu seam coal is estimated to be 161,607 Psi.

The Jawara Field in Jember Regency is a location where it is indicated that there are precious metal deposits in the form of porphyry type Gold and Copper. In this study, the focus is more on the search for metal mineral deposits related to the elements of Gold (Au) and Copper (Cu), namely the metal mineral chalcopyrite (CuFeS2) as the main carrier minerals for Au, Cu, Ag, as impurities. The results of alteration products in the form of weathered minerals are also the focus of research. The analysis used to detect metallic element content and the presence of metallic and non-metallic minerals is by petrographic analysis, mineragraphy analysis, sediment grain analysis and geochemical analysis. Based on the results of the mineragraphy analysis, it was proven that the metal mineral chalcopyrite was found in the JAFA 6 BPS sample which is a carrier mineral for the metallic copper element and silver was also found in JAFA 2 ALT. In addition, the results of the sediment grain analysis also found metal mineral grains and metal elements, namely copper and iron elements in all JAFA samples. The results of petrographic analysis show that the weathered minerals in the form of kaolinite, alunite, and smectite are products of hydrothermal alteration activities. Based on these results, the research area is divided into 3 alteration zones, namely potassic, propylitic, and argillic alteration zones. The results of the geochemical analysis showed that the highest levels of copper were found in JAFA 5 as much as 13.9 ppm and the highest levels of iron in JAFA 6 were 390.8 ppm. From the results of the analysis, it can be concluded that it is true that there are metal mineral deposits and metal elements in the form of sediment grains and porphyry-type Au and Cu elements.

Kabupaten Situbondo memiliki banyak potensi sumber daya batuan, salah satunya adalah sumber daya berupa batuan andesit. Keterdapatan batuan andesit berasal dari produk gunungapi berjenis batuan beku yang terbentuk oleh aktivitas vulkanik intermediet dengan tipe magma andesitic. Penelitian ini dilakukan di wilayah IUP Eksplorasi Daerah Rajekwesi, Kecamatan Kendit, Kabupaten Situbondo untuk mengetahui kondisi geologi, petrografi batuan, dan volume sumberdaya dari batuan andesit yang terdapat dalam WIUP Eksplorasi. Berdasarkan hasil pemetaan geologi dan analisis petrografi menunjukkan bahwa Satuan Lava Kendit di daerah WIUP hadir seluas 100%, merupakan produk lava dari Gunungapi Ringgit, berisi batuan beku andesit dan sedikit tanah sebagai produk ubahan pelapukan dari batuan tersebut. Lebih detail lagi ditunjukkan dari hasil sampel batuan yang dianalisis menggunakan analisis petrografi terdapat kehadiran mineral plagioklas, kuarsa, feldspar dengan total komposisi 60% yang menunjukkan bahwa sampel tersebut berjenis batu andesit. Estimasi volume sumberdaya mengacu pada tiga jenis sumberdaya yaitu tereka, terunjuk, dan terukur. Berdasarkan hasil perhitungan sumberdaya didapatkan volume sumberdaya batu andesit tereka sebesar 267.555.503 Ton, terunjuk sebesar 23.129.687 Ton, dan sumberdaya terukur sebesar 1.227.962 Ton

The studies become performed in Notog Village, Patigkraja District, Banyumas Regency, Central Java Province withinside the statement place of CV. Sinergi Karya Solutif with the purpose of comparing the extent of minerals and describing the way to calculate the extent mined with a greater green approach. In measuring and calculating the volumetric minerals, its miles are executed via way of means of the use of the UAV (Unmanned Aerial Vehicle) approach or drones which include drones to get aerial photos. The gathered records may be the number one records utilized in carrying out volumetric analysis. They have a look at becoming performed for 2 (two) months. The consequences acquired withinside the shape of aerial image records as number one records and a base map inclusive of geography, topography, and geology as assisting records. Mined extent acquired via way of means of processing records the use of assisting software program is 11.568.136 m3 at the same time as in records processing the use of different techniques on this guide is 123,365 m3. From the 2 calculation techniques, its miles recognized that the distinction withinside the mined extent is 768.363 m3.

Kediri Regency is a potential area for mining minerals. One of the rock excavation materials found in Kediri Regency is the type of andesite and backfill. Backfill is a mineral as a result of weathering of the parent rock, which is rich in andesite fragments and silica elements. This research was conducted at the exploration location of Tarokan Village, Tarokan District, Kediri Regency. The study was conducted using petrological analysis to obtain rock types and estimates of the availability of these minerals at the research site. Based on the results of petrological analysis, it shows that the sample is a type of backfill and andesite. However, the presence of all samples was dominated by samples of backfill that were present in abundance in as much as 98 % of the total exploration area. Based on the results of the estimation of backfill resources from geological modeling and volumetric calculations from the triangulation concept at an elevation of 110-72 mdpl, the measured resource of the Sandy Tuff unit (TU) has a volume of 2,514,150 m3, based on the results of the analysis of the average rock density of 2.172 g/cm3, the tonnage of the sandy tuff unit is 5,460,734 tons, with the tonnage of backfill from tuff 4,203,659 tons, and andesite tonnage 1,257,075 tons.