Bauxite Mining Research Articles

Provenance and Paleo-Environment of the Late Carboniferous Bauxite Formations in Southern Shanxi

The Carboniferous Benxi Formation in southern Shanxi of North China has significant bauxite resource potential; however, the source of its metallogenic material and its sedimentary environment remain unclear. The microscopy, X-ray diffraction, X-ray fluorescence spectroscopy, and inductively coupled plasma mass spectrometry methods were applied in this study to examine the mineralogical, petrographic, and geochemical characteristics. Geochemical proxies of La/Y, Sr/Ba, Al2O3/TiO2, Zr/Sc, Th/Sc, La/Sc, and Th/Co were analyzed to investigate the paleo-depositional environment and provenance of the aluminum-bearing strata. The findings indicate that diaspores are the primary ore minerals in bauxite, while kaolinite and rutile are the predominant gangue minerals. Both the bauxite and claystone/aluminous rocks exhibit high enrichment in Li, Bi, and U, with relative enrichment in In, Sb, Th, Nb, and Ta. Li is notably concentrated in the claystone/aluminous rocks, reaching up to 1994.00 μg/g, primarily occurring in cookeite and boehmite, while U is highly concentrated in the bauxite. The aluminum-bearing strata were primarily formed under alkaline-reducing conditions, with changes in acidity and alkalinity of the environment during the sedimentary diagenetic process. Marine transgressions significantly impacted the sedimentary environment of the aluminum-bearing strata, and the paleoclimate was characterized as hot and humid. The principal factors contributing to enrichment of aluminum in the sedimentary basin were the in situ weathering of aluminum-rich source rocks and the transport of clastic materials from high-aluminum source rocks. The source rocks were closely associated with intermediate-acidic magmatic rocks and potentially related to the weathering of Ordovician carbonates.

Geological Features and Ore Formation Pattern of Jinzhong Bauxite Mine, Shanxi Province, China

Bauxite is located in the lower part of the Benxi Formation, and the prospecting project shows that the distribution of bauxite ore bodies in the area is discontinuous, and there are differences in the thickness of the ore bodies. To have a clearer understanding of the bauxite ore bodies and metallogenic pattern in the census area, this study has made use of the prospecting project data, sample analysis results, etc., and combined with the geological and tectonic background of the area, the stratigraphic spreading characteristics of the bauxite ore body spatial spreading, ore characteristics and ore controlling factors in the area have been explored and researched. The bauxite ore bodies in the study area are stratified but the ore-bearing rock system is influenced by the Ordovician paleokarst geomorphology and intermittently distributed horizontally, which can be distinguished into three different ore bodies. The bauxite ore body and Shanxi-style iron ore are associated with hard clay ore, in which the ore minerals are mainly monohydrate duralumin. The natural ore type can be divided into dense bauxite and oolitic bauxite. Bauxite in this area mainly originated from the basal Ordovician carbonate rocks, with a combination of iron-rich and aluminum-rich layers, and is a typical carbonate rock sedimentary deposit of ancient weathering crust.

Land, Forest, Adivasis, and the Making of New Resource Frontiers

This article examines the growing bauxite mining activities aimed at extracting aluminum ore in the Netharhat Valley, located in the Gumla and Latehar districts of Jharkhand. Adivasis share an inseparable relationship with land and forest, which play a vital role in shaping their identity and social structure. However, the introduction of new mining frontiers has ushered in persistent extraction challenges in Adivasi’s life. Although capitalist varied interests promise Adivasis for development imperatives and their chance to uplift themselves through mining, the outcomes are both complex and multifaceted. The current situation is marked by complexity as the introduction of the new mining frontiers has skewed the balance. The article illustrates the diverse consequences of extensive mining on the Adivasis and their diminishing control over land and forests. It illustrates the varying stances on the issue of mining, and their differing opinions have created divisions among the villagers based on class, economic priorities and market opportunities. The introduction of new resource frontiers has weakened village egalitarianism and institutions, allowing for mining capitalism to penetrate the Adivasi heartlands.

Enhancing phytoremediation of bauxite mine subsoil by Jatropha curcas L. using sewage sludge and poultry sludge

Phytoremediation is a sustainable technology for cleaning up heavy metal contamination at mining sites. However, degraded soils at these sites create a harsh environment for plants to survive and properly yield biomass. In this study, sewage sludge and poultry sludge were applied as soil amendments in bauxite mine subsoil to determine their impact on the growth and heavy metal uptake of Jatropha curcas L. Both sewage sludge and poultry sludge were applied at 25% and 50%. J. curcas was grown in the amended soils for 120 days under greenhouse conditions. Changes in soil physico-chemical properties, plant growth and heavy metal uptake of J. curcas were determined after that. An increase in EC, CEC, total C, total N, total available P and total extractable K was detected in the amended soils. These improvements enhanced the growth of J. curcas, particularly in the development of above-ground plant biomass. Increased plant biomass subsequently led to higher bioaccumulation and translocation efficiency of Al, Fe, Pb and Zn. As a result, higher heavy metal removal of up to 98.03% was detected in the amended treatments. The findings indicated that the application of sewage sludge and poultry sludge improves soil conditions for plant development.

Estimasi Sumberdaya Bauksit Menggunakan Metode Ordinary Kriging Pada PT. Wahana Petra Sejahtera Kabupaten Bengkayang Provinsi Kalimantan Barat

PT. Wahana Petra Sejahtera, which operates in the bauxite mining sector, requires resource calculations as a basis for carrying out its mining activities. This research aims to determine the levels and distribution of Al2O3, SiO2, and Fe2O3 and estimate bauxite resources using the ordinary kriging method. This research uses secondary data in coordinates, elevation, test pit depth, and slope data. Data processing uses software in database creation, statistical analysis, block and composite modeling, variogram analysis, resource estimation, and model validation. The calculation results for the Jirak block show that the Al2O3 waste content is 1,488,000 tons, low-grade 4,532,000 tons, medium-grade 1,824,000 tons, and high-grade 32,000 tons. For SiO2 the average content is 13.54% and the average Fe2O3 content is 13.50%. Meanwhile, in the Sindu block the Al2O3 waste content is 64,000 tons, medium-grade 1,188,000 tons, and high-grade 3,056,000 tons. Meanwhile, the average SiO2 content is 9.13% and the average Fe2O3 content is 12.06%. The total resources in the Jirak block are 7,696,000 tons with the amount meeting the COG of 800 tons. Meanwhile, in the Sindu block, the total resources are 5,008,000 tons with an amount that meets the COG of 1,280,000 tons.

Impact of red mud on soil properties and revegetation species growth in bauxite mining land reclamation

Bauxite mining, a key aluminum production process, can cause environmental degradation, soil erosion, and biodiversity loss. Reclamation measures like reforestation and water management can restore balance. Red mud, a by-product of alumina production, can enhance soil fertility and plant growth in post-bauxite mining reclamation areas. Its alkalinity and mineral composition reduce reliance on synthetic fertilizers, promoting sustainable soil management and addressing environmental challenges. This study aimed to examine the impact of red mud on soil characteristics and the growth of plants in areas during bauxite mining land reclamation. This study was conducted in the post-reclamation area of bauxite mining in West Kalimantan. The experiment involved two treatments: red mud application and a species of revegetation plant. Plant species consist of the plants Embeng, Forest Guana, Johar, and Rambutan. The study used a randomized block design with 24 experimental units. The parameters measured in the study included pH, organic carbon, nitrogen, phosphorus, exchangeable cations, cation exchange capacity, and base saturation, while growth parameters included a high percentage of plant growth and percentages of increased stem diameter. The findings showed that adding red mud to the planting hole increased soil pH and base saturation, improved nutrient availability, and enhanced plant growth in the areas post-mining bauxite at PT Antam, UBPB West Kalimantan. The Embeng Plant is highly regarded as a suitable plant species for re-vegetating areas after bauxite mining.

Rare earth elements enrichment and extraction potential of bauxite deposits in Samar, Philippines

Abstract Rare earth elements (REE) play an integral part of modern life, from smartphones to satellites. Dubbed ‘critical metals’, the demand for REE has significantly increased, driven by the growth in global production for green technologies such as e-vehicles, solar panels, wind turbines, and other energy-economic infrastructure. Therefore, there is a need to explore alternative REE sources to ensure continued development of emerging green technologies. A possible alternative REE source is bauxite, which is soil that forms from intense weathering of aluminum oxide-rich rocks exposed to tropical climate. This paper investigates the REE enrichment and extraction potential from bauxite deposits in Paranas, Samar, Philippines. The sampling survey included collection of rock and soil on surface exposures, test pits, and drill cores from accessible portions of the bauxite mineral reservation site. The soil and parent rock samples collected were then subjected to various geochemical and mineralogical analyses. The main ore minerals of aluminum are gibbsite and boehmite; with minor goethite, hematite, and magnetite. Investigation of the geochemical composition of the bauxite reveals a total REE content of up to ~300 ppm, which is one of the highest REE and critical metal content among geological deposits in the country. These results will provide inputs in the design of a green and economical process to recover REE from bauxites. If the bauxite deposits prove to be a valuable REE resource, this study will help maximize the economic potential of the mineral resource in the Philippines and contribute to an economically efficient and environment-friendly way to produce e-tech elements for the country.

Plant Agency in the Guianas: Attraction, Assault, and Animacy

This article uses ethnographic and ethnobotanical methods to examine relationships between animate and agentive plants and human beings among the Makushi, Pemon, Karinya, and other Indigenous and mixed-Indigenous peoples in the Guianas. It considers representations of these plants and related ontologies in the archival record and contrasts these accounts with more recent ethnographic descriptions based on the authors’ fieldwork across Guyana and Venezuela. It thinks about these plants as agentive beings (with regard to animist ontologies and sometimes physical properties) within a variety of contexts. Today, the territories of these Indigenous peoples tessellate with extractive frontiers, which center around gold, diamond, and bauxite mining, as well as oil prospecting, forestry, and plantation agriculture. In this context, these plants emerge as active and animate agents. They also emerge as such agents in contexts of subsistence, shamanism, and assault sorcery, as well as sexual and romantic attraction, which can act with or without human impetus. The question arises as to the nature of the relationships between such plants and their users, for example, shamans ( piaimen), assault sorcerers ( kanaima), hunters, gardeners, and miners, within a variety of contexts. Based on the authors’ long-term fieldwork, the article examines animate plants and argues that they evince special botanical agencies among the Indigenous communities with whom the authors have worked in the Guianas. How are animate plants positioned within these practices and contexts? And how do they exert agency therein as plant persons?

Bauxite mine and alumina refinery workers: mortality and cancer risk.

Aluminium industry workers are at risk of long-term health consequences. To investigate mortality and cancer incidence in bauxite mine and alumina refinery workers. A pre-existing cohort of workers was re-linked with the Australian National Death Index, and the Australian Cancer Database to provide additional death (7 years) and cancer (9 years) data. Standardized mortality ratios (SMRs) and standardized incidence rates (SIRs) were estimated by job category, duration of employment and time since first employment. Linkage was performed for 6935 (6207 male) workers. Compared with the general population, there was a reduced or similar risk of death for mine/refinery workers for all causes except mesothelioma which was increased amongst male production workers [SMR 2.42, 95% CI 1.11-4.60]. Mesothelioma incidence was also increased amongst males [SIR 2.50, 95% CI 1.60-3.71]. Male office workers had a greater incidence of prostate cancer [SIR 1.30, 95% CI 1.06-1.57] and thyroid cancer [SIR 3.47, 95% CI 1.66-6.38]. Melanoma incidence was increased in female office workers [SIR 2.27, 95% CI 1.36-3.54]. Lip cancer incidence was increased in male maintenance/production workers [SIR 2.04, 95% CI 1.02-3.65]. Overall cancer incidence was otherwise similar to the general Australian population. Overall risk of death and incidence of cancer for bauxite mine and alumina refinery workers was similar to the general population. Incidence and risk of death from mesothelioma were higher, likely due to historic asbestos exposure in this and other industries. The increased risk of melanoma, lip, prostate and thyroid cancers requires further investigation.

“Future Uncertain!” — Dispossession by Mining and Young Men - Mining Company Engagements in Eastern India

A protracted movement emerged in Southern Odisha, eastern India, in 1993 that stalled for over 18 years India’s first private bauxite mining project, Utkal Alumina International Limited, in Kashipur. The movement went through several ups and downs and finally declined in 2010. The project involved the dispossession of 32 villages. The movement’s decline coincided with many young villagers turning to the mining company to obtain low-paying jobs and paltry benefits. Most of the villagers who did this were earlier at the forefront of the movement. This article explores why and how these young, semi-educated, and dispossessed men from Scheduled Tribes and Scheduled Castes responded to this situation. It critically explores their actions and utilizes the sociological concept of responsibilization to understand the actions of these young men facing acute uncertainty about their futures in a context where their existing and familiar economic and social world was rapidly dissolving before their eyes.

Prediction and practical application of bauxite mineralization in Wuzhengdao area, Guizhou, China.

Wu-Zheng-Dao District in China is the world's most famous mining areas. It hosts several world-class deposits, such as Xinming, Datang and Luolong bauxite deposits. Although this area still has significant potential for the discovery of new deposits, mineral prediction has become increasingly diffcult as the number of shallow deposits diminishes. Therefore, it is necessary to explore new and effective metallogenic prediction methods.Weights of evidence and machine-learning algorithms were used for mineral prospecting in this study. This study used a confusion matrix, receiver operating characteristic (ROC) curve,and prediction efficiency curve to evaluate the prediction results of each machine algorithm. The results showed that 95.9% of the deposits were located in high and distant scenic areas, accounting for 10% of the total area.The prospectivity map of the Wu-Zheng-Dao district shows that the high prospective areas are generally confined to the claystone and carbonatite rocks of the Eastern region, in particular, of the clay layers, and several areas of high prospectivity also occur in the Southern Cross Domain. According to the predicted results, after on-site exploration, design, and construction, Yanfengqian bauxite deposit was discovered, with an average thickness of 1.82 meters; The average content of Al2O3 is 61.24%; The resource amount is 28.9503 million tons.

First Report of Leaf Blight of Osmanthus fragrans Caused by Diaporthe eres in China.

Osmanthus fragrans is an evergreen garden tree species, with high ecological, social, and economic benefits (Lan et al. 2023), which is widely planted in Guizhou Province. From late April to June 2023, a leaf blight disease was observed on O. fragrans in a bauxite mining area in Qingzhen City, with an incidence of ~50%. Symptoms first appeared at the leaf tip or margin, as irregular brown spots, which gradually coalesced into dark brown patches until the leaves withered and fell off. Symptomatic leaves were collected and surface disinfected with 2% NaClO for 30 s, 75% ethanol for 30 s, rinsed 3 times in sterile ddH2O, air-dried and placed on potato dextrose agar (PDA) medium and incubated at 25°C for 7 d. Fungal colonies on PDA of 9 similar obtained isolates were white, with at least one concentric ring. The reverse was light yellow and gradually turned brown. At 12 d, the pycnidia on PDA was gray to black, spherical or conical, with a diameter of 305.15 μm (n=20). The conidial horns oozed out from pycnidia after 25 d of incubation on Pinus massoniana needles. The alpha conidia were unicellular, fusiform, hyaline, had a guttule at each end, and measured 6.24 ± 0.10 μm × 2.48 ± 0.04 μm (n=50). No beta or gamma conidia were observed. The morphological characteristics were likely to Diaporthe spp. (Gomes et al. 2013). DNA of isolates GH02, GH06 and GH08 was extracted. The internal transcribed spacer region (ITS) and partial sequences of translation elongation factor 1-alpha (TEF1-α), calmodulin (CAL), beta-tubulin (TUB2), and histone H3 (HIS) genes were amplified with primers ITS1/ITS4 (White et al. 1990), EF1-728F/EF1-986R, CAL228F/CAL737R (Carbone and Kohn, 1999), βt2a/βt2b and CYLH3F/H3-1b (Crous et al. 2004; Glass and Donaldson, 1995), respectively. The sequences of ITS, TEF-1α, TUB2, CAL and HIS were deposited in GenBank (GH02: PP813499, PP813844, PP813846, PP813848 and PP813850; GH06: PP813500, PP813845, PP813847, PP813849 and PP813851; GH08: PP507168 and PP529956 to PP529959). BLAST results showed the sequences of GH08 were highly identical to sequences of Phomopsis mahothocarpi (NR147522 [ITS], 527/530), P. mahothocarpi (MW700277 [TEF-1α], 367/372), D. eres (OR885862 [TUB], 513/513), D. celeris (ON221721 [CAL], 484/486), and D. eres (OP968956 [HIS], 477/477). A phylogenetic tree constructed with MEGA X using Neighbor-Joining algorithm (Felsenstein, 1985) indicated the isolate GH02, GH06 and GH08 separated from D. eres CBS 297.77 previously reported from O. aquifolium in Netherlands, as well as D. osmanthi and D. fusicola from O. fragrans in China (Gomes et al. 2013; Long et al. 2019; Si et al. 2021). Based on these results, the three isolates were identified as D. eres (Chaisiri et al., 2021). The isolate GH08 was deposited in the Forest Protection Laboratory, Guizhou University. To confirm pathogenicity, spore suspensions (1×105 spores/mL) of GH08 were sprayed on healthy detached leaves (n=10) and leaves of 3-year-old potted O. fragrans seedlings (n=8). An equal volume of sterile water was sprayed for the control. Then they were placed at 20°C and 70-80% RH. Similar leaf blight symptoms appeared after 5 and 15d on the inoculated leaves and seedlings, respectively. The re-isolated fungus, was identical to D. eres based on morphological and molecular analysis, thus fulfilling Koch's postulates. To our knowledge, this is the first report of D. eres causing leaf blight of O. fragrans in China, supporting a basis for developing effective methods to manage this disease.

Social risks assessment of the supply chain of an aluminium semi-finished profile for window

Abstract Purpose Aluminium is among the most energy-intensive industries in the world and is produced from mining operations in bauxite mines. The effects on the environment of the entire aluminium supply chain, especially mining, also entail social risks. This article aims to understand the potential social risks along the supply chain of aluminium by focusing on a semi-finished frame for windows through the use of the Product Social Impact Life Cycle Assessment (PSILCA) database. Method Social Life Cycle Assessment (S-LCA) was implemented by following the Social Life Cycle Assessment of Products And Organizations 2020, to analyse the potential social risks and opportunities associated with the aluminium sector. Specifically, the PSILCA database, designed for S-LCA, was used to evaluate the background processes of the aluminium supply chain of an Italian company specialized in surface treatment of aluminium semi-finished products used in the production of doors and windows. Results The primary social risks manifest in the background processes. Comparing these findings with the literature review, it is straightforward to attribute them to the mining phase of bauxite, which constitutes the initial stage in aluminium production and occurs in various regions globally. Specifically, the highest social risk is associated with “Corruption in the public sector”, likely linked to Italy. Additionally, the study reveals a positive impact in terms of “Contribution to economic development” as also revealed by the literature review. Conclusions An analysis of the potential social risks within the aluminium supply chain was provided, addressing the research gap between the utilization of S-LCA methodology and its application within the sector. Additionally, the PSILCA database was employed for investigating the background processes in the case study. However, a social performance assessment using primary data would be required to enhance the representation of the evaluated production system.

Topsoil volume optimization in the restoration of post‐mined areas

Transferring topsoil to severely degraded areas, such as mined areas, is an effective restoration technique. However, topsoil from pristine areas is a limited resource, making it important to seek techniques that optimize its use. Thus, this study assessed the effects of adding a small topsoil volume (10 L/m2 or 1 cm layer), a seed mix of 14 species, and litter (30 L/m2) alone and in different combinations in the restoration of a rupestrian grassland area degraded by bauxite mining. The substrate in the degraded area was turned prior to applying treatments. Vegetation cover, density of individuals, and species richness were measured 30 months after the experiment was set up. The isolated use of each material and the simultaneous addition of topsoil to the seed mix were not effective. The simultaneous use of topsoil, litter, and seed mix provided the best result, presenting the highest vegetation coverage (60%), density (67 ind/m2), and species richness (26 in 12 m2). Although, to a lesser extent, the combination of seed mix and litter also presented satisfactory results. The combination of the three materials promoted the revegetation of an area that had been without vegetation for around 50 years, presenting a density of individuals and species richness comparable to those obtained with the use of thick topsoil layers (15–30 cm). Furthermore, the topsoil volume used was optimized.

Feminist perspectives on environmental justice and health in Jamaica.

Jamaica is an island nation with a history that is informed by Taino settlement, European colonisation, chattel slavery, disinvestment, and continued extractivism. This perspective paper leverages a historical analysis to explore environmental injustices affecting the health and quality of life of Jamaicans living in Jamaica. This article hopes to contribute to a growing but limited body of scholarly research that contends with environmental and climate justice in the context of the Caribbean. In discussing a lack of critical environmental infrastructure, such as reliable solid waste management, and the impacts of extractive industries, such as bauxite mining, the paper intends to highlight the environmental, public health, and social harms that are produced. Employing an intersectional approach grounded in Black feminist epistemology put forward by Patricia Hill Collins, the authors use their lived experiences as a source of knowledge. The paper analyses how these environmental injustices harm Jamaican communities at large but underscores the compounded challenges faced by Jamaican women who experience marginalisation on the basis of gender, urban/rural residency, and class. The paper concludes by urging researchers, policymakers, regulatory bodies, and other stakeholders to conduct further research and create sustainable and equitable environmental standards that have considerations for environmental injustice in Jamaica.

Impact of Bauxite Mining on Heavy Metal Levels in Kara Kara Blue Lake and Associated Active Tailing Pond

Impact of Bauxite Mining on Heavy Metal Levels in Kara Kara Blue Lake and Associated Active Tailing Pond

Experimental Study on Replacement of Cement with GGBFS and Manufacturing Sand with Baux-ite Mining Waste in Concrete

Experimental Study on Replacement of Cement with GGBFS and Manufacturing Sand with Baux-ite Mining Waste in Concrete

Social hotspots in the automotive industry’s aluminum value chains—combining primary and generic data

Abstract Purpose The automotive industry and its suppliers have been facing increasing challenges in the sustainable sourcing of raw materials on environmental and social levels. To identify social risks in the value chain of aluminum in the automotive sector, this study aimed to examine how a generic hotspot analysis based on S-LCA can be conducted and support the reporting according to new legislative requirements such as the German Act on Corporate Due Diligence Obligations in Supply Chains. Methods This study investigated the social risks in the supply chains of two selected aluminum components of an aluminum company using a generic social hotspot analysis based on the UNEP Guidelines for Social Life Cycle Assessment of Products and Organizations 2020. The study employed the generic PSILCA© database and different additional indicators for the assessment. The UNEP Guidelines 2020 used in combination with the associated methodological sheets were beneficial in structuring the procedure within the social hotspot analysis. They gave the inexperienced user a guide, which led to the results presented in this work. Results and discussion A high number of social hotspots in upstream processes outside Europe across the different investigated indicators for both supply chains assessed were detected. Most social risks were identified in Guinea, as well as in a European and an Asian Country in the stakeholder categories “Workers” and “Local community.” Especially, the alloy element production in the Asian Country and the bauxite mining in Guinea showed an above-average number of social hotspots. The implementation of the work was associated with an enormous effort in information collection about the supply chains to be investigated and depended on the direct suppliers’ willingness to contribute. The need for a safe and supporting environment for suppliers to enhance transparency was identified. Conclusions Combining generic and company data to conduct a social hotspot assessment (e.g., using PSILCA©) to meet legislative requirements proved to be a suitable approach for complex supply chains such as the automotive one. Despite this, limitations of the PSILCA© database and potential for improvement were acknowledged regarding industry-wide social assessments of supply chains. Additionally, the study serves as an application example of the UNEP Guidelines 2020 and the activity variables for science in practice. Further development and standardization of social indicators and activity variables for impact measurement were identified as a research priority.

Waste Management of Red Mud and Fly Ash to Utilize in Road Subgrade Material

Red mud (RM) is a waste material obtained during the production of aluminum from bauxite minerals. RM causes environmental pollution due to its high alkaline properties. Therefore, RM materials are stored in waste reservoirs. As production continues, the number of required waste reservoirs increases day by day. This study aims to utilize RM waste material in construction structures to contribute to the economy. The research investigates the potential use of RM waste material as road fill material. RM was improved using another waste material of fly ash (FA) since RM has low strength. Atterberg limit tests, compaction tests, unconfined compression tests, CBR tests, and SEM analyses were conducted on stabilized RM samples. In the physical properties of stabilized RM, Atterberg limits and optimum moisture content increase and density decreases since FA content increases. In the mechanical properties of stabilized RM, unconfined compressive strength, initial and secant modulus of elasticity, and California bearing ratio increase and maximum peak strain decreases since FA content and curing period increase. SEM images prove the increase in mechanical properties due to the cementation products (CSH and CAH gels) formed in the microstructure of stabilized RM. The results showed that RM waste stabilized with FA can be used as road subgrade material.

Bauxite Resource Estimation Analysis Using Ordinary Kriging and Inverse Distance Weighting in West Kalimantan

PT X is a mining company engaged in bauxite mining which is located in Nanga Tayap District, Ketapang Regency, West Kalimantan Province. Currently the company is carrying out further exploration activities to find potential bauxite resources which will later be upgraded into reserves for mining. In resource estimation, there are several methods that can be used, such as the Nearest Neighbor Point method, Inverse Distance Weighting, and Ordinary Kriging. This research aims to analyze two resource estimation methods, namely Inverse Distance Weighting and Ordinary Kriging for resource estimation and choose the best method based on geological conditions and RMSE value parameters. Based on the results of this research, the estimated value of bauxite resources using the IDW method obtained a tonnage of 1,046,874.99 tons with an average Al₂O₃ content of 47.28%. Meanwhile, the estimated bauxite resource value using the OK method obtained a tonnage of 1,046,875.01 tonnes with an average Al₂O₃ content of 48.15%. Based on the calculation of the Root Mean Squared Error (RMSE) value from the two methods, the respective RMSE values were obtained, namely IDW = 0.0001263 and OK = 0.0084145. From these results it can be concluded that the best method for estimating bauxite resources in the Enggang block is the Inverse Distance Weighting (IDW) method.