Lateritic Deposits Research Articles

National Virtual Core Library HyLogging data and Ni–Co laterites: a mineralogical model for resource exploration, extraction and remediation

ABSTRACTThe National Virtual Core Library (NVCL) HyLogging core-scanning system generates mineralogical information from visible, short-wave infrared and thermal infrared spectroscopic data. Currently, HyLogging data are freely available for more than 1500 drill holes via the AuScope Discovery Portal and various Geological Survey websites. With any new technology, there is commonly a lag between provision and take-up by users that can be aided by the publication of case studies in the scientific literature. This paper uses the Mt Davies nickel–cobalt (Ni–Co) laterite deposits, located in northwest South Australia, as a case study to assess the accessibility and representation of HyLogger data and provides an example of its application to all aspects of resource mining: exploration, extraction and processing, and remediation. In this study, we combine HyLogger-derived scalars indicating Fe-oxide and clay mineralogy with historical geological logs and assay data. In general, background Ni grades (<0.1 wt%) are linked to the presence of montmorillonite + hematite ± goethite, moderate grades (0.1–1.0 wt%) are associated with goethite ± nontronite ± saponite ± kaolinite ± montmorillonite, and higher grades (1.0–2.0 wt%) are coincident with goethite and minimal clay alteration, suggesting that goethite hosts Ni mineralisation. Gibbsite, where it occurs, is found immediately above zones of moderate to high Ni grades and may be an important proximal indicator mineral of nickeliferous laterite. Such a case study serves to suggest opportunities for further data modelling and search and query functionality that could facilitate increased use of this important digital geoscience data resource by the Australian minerals industry for all aspects of resource exploitation: exploration, extraction, processing, and environmental remediation.

Scandium speciation in a world-class lateritic deposit

Scandium (Sc) has unique properties, highly valued for many applications. Future supply is expected to rely on unusually high-grade (up to 1000 ppm) lateritic Sc ores discovered in Eastern Australia. To understand the origin of such exceptional concentrations, we investigated Sc speciation in one of these deposits. The major factors are unusually high concentrations in the parent rock together with lateritic weathering over long time scales in a stable tectonic context. At microscopic and atomic scales, by combining X-ray absorption near edge structure spectroscopy, X-ray diffraction and microscopic and chemical analyses, we show that Sc-rich volumes are associated with iron oxides. In particular, Sc adsorbed on goethite accounts for ca 80 % of the Sc budget in our samples. The remaining is incorporated in the crystal structure of hematite, substituting for Fe3+. Scandium grades reflect the high capacity of goethite to adsorb this element. In contrast, the influence of hematite is limited by the low levels of Sc that its structure can incorporate. These crystal-chemical controls play a major role in lateritic Sc deposits developed over ultramafic–mafic rocks.

Simulation of weathered profiles coupled with multivariate block-support simulation of the Puma nickel laterite deposit, Brazil

Modelling and assessing spatial variability and uncertainty of mineral deposits is critical for both capital investments in mining projects as well as operational issues once a mine is developed. However, traditional approaches for modelling geological domains and geostatistical estimation provide smoothed representations of the pertinent deposit attributes, ignore spatial variability and, thereby, can mislead downstream decisions. Spatial variability and related uncertainty in modelling mineral deposit characteristics of interest, ranging from metal content and geological boundaries to geomechanical - geotechnical rock properties, can be modelled and quantified by stochastic spatial simulations. This is demonstrated through a detailed, step- by-step application to the Puma deposit, a major nickel lateritic asset in Brazil, part of the Onça-Puma mining complex. To integrate the variability of the regolith profiles of the deposit, their thicknesses are calculated after an unwrinkling process is applied and the deposit is then jointly simulated using min/max autocorrelation factors (MAF). The realizations serve as geological boundaries within which Ni, Co, Fe, SiO2, MgO and Dry-tonnage factor (DTF) are subsequently jointly simulated directly at block support scale. The final result is a series of equally probable representations of the Puma deposit, which are used to quantify and assess the uncertainty about key aspects of the project at the Puma deposit, such as the uncertainty of the in-situ resources documented herein, and the strict control of the ore's quality that feeds the ferronickel processing plant. The framework presented shows the advantages of the MAF and direct block simulation approaches for the efficient joint simulation of spatially variant geological attributes of large deposits for industrial environments. The methods presented are general, new in the context of geotechnical and geomechanical engineering, and can assist in the modelling of spatial variability and quantification of uncertainty linked to geotechnical rock properties and pertinent lithological boundaries.

An overview of nickel mineralisation in Africa with emphasis on the Mesoproterozoic East African Nickel Belt (EANB)

Nickel production in Africa takes place principally in Botswana, South Africa and Zimbabwe, with much of the South African and Zimbabwean production being a by-product of platinum-group element mining in the Bushveld Complex and Great Dyke. Several large nickel deposits have been discovered elsewhere in Africa but until recently, their development has been hindered by political risk and limitations in energy and transport infrastructure. Most of the continent is significantly underexplored with respect to base metals, including the area covered by the East African Nickel Belt (EANB). The known nickel deposits of the EANB all occur in mafic-ultramafic intrusive rocks of the Mesoproterozoicage Kibaran igneous event. These intrusive bodies take the form of medium to large layered intrusions, small dynamic magma conduits (chonoliths and sills) and dyke swarms. Laterite deposits are developed over exposed dunite and peridotite lithologies in the basal sequence of larger layered intrusions, whereas nickel sulphide deposits are developed at the base of the small chonoliths. Geochronological and geochemical data suggests that all intrusions in the EANB formed in a single magmatic event (1350 to 1400 Ma) and were derived from a picritic parental magma, which was variably contaminated in mid to upper-crustal staging chambers by metasedimentary rocks. As a result, nickel sulphide mineralisation was formed in all of the intrusions, but in most, the grades and tenors are too low to be considered economic in the foreseeable future. In the 1970s, government-led regional surveys identified a large nickel laterite deposit at Musongati in Burundi and a nickel sulphide deposit at Kabanga in the northwest of Tanzania. These deposits have subsequently been explored and delineated by mining companies, but they remain undeveloped due to their distance to the coast and a lack of transport and energy infrastructure. The Kabanga sulphide deposit now comprises a total mineral resource of 58 million tonnes grading 2.6% nickel. The Musongati laterite deposit comprises an overall resource of 122 million tonnes with a grade of 1.4% nickel.

Hydrometallurgical processing of nickel lateritic ores

Nickel production is a very important activity for the European Union because nickel is a unique constituent of stainless steel. Europe has lateritic (oxidic) ore deposits along a very well-known belt starting from the Alps and ending to the Himalayas. The lateritic belt passes through western Balkans and Greece and continues through Turkey to Asia. The known lateritic deposits in Serbia are located in three different areas called: Zapadna Morava (Rudjinci, Veluce, Ba), Sumadija (Lipovac, Kolarevici, Bucje) and Mokra Gora, which have many natural resources such as forests, rivers, etc. Therefore, it is very important to understand and show hydrometallurgical treatments of lateritic ores via mining and metallurgy in different parts of the world. In this paper, several exploitation scenarios for hydrometallurgical treatment and benefication of lateritic ores will be shown: Direct Nickel Process, Ravensthorpe and Murrin Murrin in Australia and Meta Cobalt Nickel in Turkey.

Bioleaching of nickel by Aspergillus humicola SKP102 isolated from Indian lateritic overburden

The lateritic deposits spread over the Eastern Ghats of Sukinda Valley, Odisha, India, produce a huge amount of overburden annually as a byproduct of chromite mining. This chromite mining overburden contains nickel, the only source of the metal in the country. During this study Aspergillus humicola SKP102, an indigenous fungus isolated from the mining overburden was employed for the leaching of nickel. About 53.89% of the nickel could be leached by the fungus when grown in batch mode using a Czapek dox medium containing 2% (w/v) of the mining overburden. The parameters affecting bioleaching were optimized in order to grow the fungus and leach the metal. Of the different options of cheap carbon sources, straw infusion and molasses emerged as viable options for the growth of the fungus and the leaching of nickel. Two-step and indirect techniques were also used for this purpose, and they resulted in 53.09% and 65.04% Ni leaching respectively. Adding diluted sulfuric acid to the leaching medium resulted in 97.05% nickel recovery from the overburden pulp. A. humicola SKP102 could be a potential tool for leaching nickel from the mining overburden.

Thermodynamics of the Reduction Roasting of Nickeliferous Laterite Ores

The global nickel sulphide resources are becoming more difficult to mine and, as a result, there is increasing interest in the current and future development of the oxidic nickel laterite deposits. In comparison to the sulphide ores, the nickel laterites cannot be readily upgraded by conventional means and growing attention is being focused on the development of new methods for processing these ores. In this paper, firstly, brief overviews of laterite ore mineralogy and the conventional techniques used to extract the nickel from both the limonitic and the saprolitic nickeliferous laterites are provided. Secondly, previous research on the thermodynamic modelling of the reduction of the laterites is discussed. Thirdly, an improved thermodynamic model is used to predict the equilibrium products arising from the solid state reduction of both the limonitic and the saprolitic ores. Based on these thermodynamic predictions, the reduction behaviors of the two ore types are compared in terms of nickel recovery and grade in the ferronickel product. The effects of reduction temperature, ore composition and carbon additions were studied. Finally, the results from the simulations are compared to the experimental data available in the literature.

Geological knowledge discovery and minerals targeting from regolith using a machine learning approach

We identify and understand the diverse nature of Ni mineralisation across the Australian continent using Self-Organising Maps, an unsupervised clustering algorithm. We integrate remotely sensed, continental-scale multivariate geophysical/mineralogical data and combine the outputs of our machine learning analysis with Ni mineral occurrence data. The resulting Ni prospectivity map identifies the location of Ni mines with an accuracy 92.58%. We divide areas of prospective Ni mineralisation into five clusters. These clusters indicate subtle but significant differences in regolith and bedrock geophysical/mineralogical footprints of Ni sulphide and Ni laterite deposits. This information is used to identify and understand the nature of potential Ni targets in regions where prospective bedrock mineralisation is concealed by regolith materials. Our machine learning approach can be applied to the analysis of other mineral commodities and at local-/prospect scales.

Rare earth element fractionation in heterogenite (CoOOH): implication for cobalt oxidized ore in the Katanga Copperbelt (Democratic Republic of Congo)

Heterogenite (CoOOH) is the most abundant cobalt oxide mineral in the Katanga Copperbelt, which hosts around half of the world's known reserves of mineable cobalt. Heterogenite formed by the oxidation of Co-sulfides and accumulated as residual deposits during a Pliocene weathering event. Bulk analysis samples of oxidized cobalt ore samples containing with variable heterogenite concentration display two rare earth element (REE) patterns: (i) Type 1 is enriched in middle REE, with a negative cerium anomaly and a relatively low REE content; (ii) Type 2 is variably enriched in light REE (LREE), without a cerium anomaly and with higher REE content. However, in situ LA-ICP-MS reveals that the Type 2 patterns are due to the mixing of heterogenite with a LREE-rich mineral.Weathering processes leading to heterogenite formation mainly consist of water–rock interactions at high Co activity, in the near-surface environment. These result in the formation of a lateritic deposit. Heterogenite precipitates at near-neutral pH conditions together with manganese oxides. REE are mainly fractionated between these Co- and Mn-oxide minerals. In the deeper part of the oxidized profile, cobalt activity decreases and the heterogenite stability field shifts to alkaline pH conditions due to the dissolution of dolostone in the bedrock. In such an alkaline environment, REE speciation is mainly driven by carbonate complexation/precipitation. This environment would be favorable for the formation of REE-rich carbonate which is intimately associated with heterogenite (LREE-rich Type 2 patterns).The combined whole-rock and in situ geochemical analyses presented here clearly help (1) to distinguish the REE signature of the Co oxidized ore (mineral paragenesis comprising heterogenite) and of heterogenite itself, and subsequently (2) to highlight two different chemical environments for the formation of heterogenite in supergene ores. This study therefore improves the understanding of REE behavior and metal mobility in near-surface environments, and more particularly in environments where the supergene ores form. In the future, the approach developed here can be applied to other Co–Ni–Mn lateritic deposits such as those in New Caledonia and Cameroon.

A two-stage thermal upgrading process for nickeliferous limonitic laterite ores

Sulphide ore deposits are becoming increasingly less viable as a source of nickel, driving recent interest in the development of nickel laterite deposits. The difficulties with the current methods of nickel metal production from these oxide ores arise mainly from the inability to produce a concentrate analogous to that obtained in the flotation of sulphide ores, resulting in high production costs. In this work, a two-stage reduction and thermal growth process is proposed for the treatment of the nickeliferous limonitic laterite ores to produce a ferronickel product, recoverable by magnetic separation. An initial reduction roast of the ore with 6% coal and 4% sulphur additions at 600°C for 1 h, followed by particle growth for 1 h at 1000°C, produced a ferronickel concentrate with a nickel grade of 4% and a nickel recovery of 93·2%. The impact of particle growth temperature and retention time at temperature on the ferronickel particle size was also studied. For the control conditions, typical ferronickel particles produced were 10–20 μm in size. The particle size did not significantly change at temperatures higher than 1200°C or for retention times beyond 60 min.

Why heap leach nickel laterites?

With the majority of nickel naturally occurring in laterite ores but the majority of production still in sulphides, it is high time there was a standalone commercial nickel laterite heap leach operation. The broad success of heap leaching of other metals has allowed hitherto uneconomic deposits to undergo successful economic exploitation, and heap leaching now accounts for at least one third of global copper and gold production. Nickel laterites are no different, every major and several junior nickel miners have evaluated nickel laterite heap leaching over the past decade and shown projects to have robust economics, with much lower capital costs than alternative hydrometallurgical options which have in general been dismal failures, both technically and commercially.Nickel Laterite Heap leaching is simple and flexible, and can be applied to the many laterite deposits that currently have no realistic path to production.This paper aims to review the current state of nickel laterite processing and aims to show that heap leaching of nickel laterites is a viable and economically attractive alternative.

Microwave carbothermic reduction roasting of a low grade nickeliferous silicate laterite ore

The known resources of nickel sulphide ores are quickly diminishing and in order to satisfy future nickel demands, nickel laterite deposits are being investigated as an alternative. Currently, expensive leaching and smelting processes are used to process the nickel laterite ores. The objective of the present research was to produce a high grade nickel concentrate via microwave carbothermic reduction roasting followed by magnetic separation. A thermodynamic model was developed for the roasting process in order to determine the optimum experimental conditions. The experimental variables investigated were: microwave energy and argon shrouding for the reduction tests and the magnetic field strength for the concentration stage. The behaviours of nickel and cobalt were studied in the reduction and magnetic separation processes. By optimizing the reducing and magnetic separation conditions, a high grade concentrate containing 9.2% nickel with a nickel recovery of 88.8% was achieved.

Lateritization process of peridotites in Siruka, Choiseul, Solomon Islands

The lateritic weathering crusts exposed in Siruka, Choiseul Islands, Solomon Islands, were developed on the expense of serpentinized peridotite underlain by Siruka schists and Voza lavas with a subhorizontal contact. The lateritic profiles consist of three generalized zones: bedrock, saprolitic zone (weathered and decomposed zone) and the limonitic zones. The profiles demonstrate variations in depths and continuity but illustrate mineralogy and geochemical affinity down profile and are analogous to saprolitic nickel laterite deposits. Silica and magnesia in the bed rock and the saprolitic zones have been removed and only the residual elements (iron, chromium, aluminium, manganese, cobalt and nickel) remain in the limonitic zone. These elements are relatively concentrated as a result of the removal of the soluble elements. Nickel is associated with silica and magnesia, as lizardite ormixed gels (garnierite nickel ore) at the weathering fronts. On the other hand, nickel, with generally low concentrations (

Erratum to: Mobilization and redistribution of major and trace elements in a lateritic profile: the Sheikh-Marut deposit, NW Iran

The Sheikh-Marut deposit is one of typical REE-rich lateritic deposits of Permian age in northwest of Mahabad, NW Iran. In this study, using geochemical techniques for calculation of mass changes and correlation coefficients, the effective factors in mobilization and redistribution of major and trace elements during lateritization processes across a selected profile were considered. Based upon TOC (total organic carbon) values, the ores across the profile were divided into two parts: (1) TOC-rich in the upper part and (2) TOC-poor in the lower part of the profile. Mass change calculations illustrated that elements such as Al, Fe, Ti, Th, V, Ni, Co, Cr, Be, Nb, Zr, Hf, Ta, and Sn were leached out from the TOC-rich part and were added to the TOC-poor section during lateritization processes. In addition, elements like Ca, K, Mg, Na, P, Pb, Cu, Zn, Cs, Y, Rb, Sr, Ba, and U were leached out from both the TOC-rich and the TOC-poor sections of the profile, and elements such as Mn, As, Cd, Tl, and Ga were enriched during lateritization. Incorporation of the results obtained from mass change calculations and correlation coefficients among elements demonstrated that factors such as presence or absence of organic ligands, physico-chemical conditions (Eh and pH) of depositional environment, and mineral control are three principal factors dominating leaching and redistribution of major and trace elements in the studied lateritic profile. The obtained results also revealed that scavenging by metallic oxides was rather more effective than adsorption mechanism in concentration of most trace elements in the studied ores.

Advances in microbial leaching processes for nickel extraction from lateritic minerals - A review

Lateritic nickel minerals constitute about 80% of nickel reserves in the world, but their contribution for nickel production is about 40%. The obstacles in extraction of nickel from lateritic minerals are attributed to their very complex mineralogy and low nickel content. Hence, the existing metallurgical techniques are not techno-economically feasible and environmentally sustainable for processing of such complex deposits. At this juncture, microbial mineral processing could be a benevolent approach for processing of lateritic minerals in favor of nickel extraction. The microbial mineral processing route offers many advantages over conventional metallurgical methods as the process is operated under ambient conditions and requires low energy input; thus these processes are relatively simple and environment friendly. Microbial processing of the lateritic deposits still needs improvement to make it industrially viable. Microorganisms play the pivotal role in mineral bio-processing as they catalyze the extraction of metals from minerals. So it is inevitable to explore the physiological and bio-molecular mechanisms involved in this microbe-mineral interaction. The present article offers comprehensive information about the advances in microbial processes for extraction of nickel from laterites.

Geochemical characteristics of laterite: the Jurassic Zan deposit, Iran

The Zan lateritic deposit is located in ~25 km southeast of Damavand, Tehran province, Iran. This deposit was developed as stratiform at the base of Shemshak (sandstone and shale) Formation of Jurassic age. Mineralogical data shows that rock-forming minerals in this deposit include kaolinite, diaspore, hematite, goethite, anatase, boehmite, siderite, rutile, quartz, titanomagnetite, zircon and pyrite. The values of absolute weathering index calculated on the assumption of Th as an immobile element indicate that lateritization processes at the Zan were accompanied by enrichment of elements like Al, Fe, Zr, Nb, Ni, Cr, Co, Y, V, and REEs and by leaching-fixation of elements such as U, Mn, Sr, Ba, and Ca. Combination of the data obtained from mineralogical and geochemical investigations reveals that pH variation of weathering solutions, oxidation potential, adsorption, presence of organic matters, preferential sorption by metallic oxides, presence in resistant minerals and fixation in neomorph phases played prominent role in distribution of elements in the Zan lateritic deposit. With considering of correlation coefficients among elements, the minerals such as zircon and rutile can be regarded as potential hosts for REE in the ores. Palaeogeography evidence as well as geochemical indices like TiO2/Al2O3 and Eu/Eu* anomaly suggests that this deposit is a weathering product of basalt. ARTICLE INFO

Framboidal pyrite and bacterio-morphic goethite at transitional zones between Fe–Ni-laterites and limestones: Evidence from Lokris, Greece

The Fe–Ni laterite deposits at the Lokris area of Greece, which are a major source of nickel, are characterized by multistage erosion/re-deposition and intense tectonic activities. This study is focused on certain mineralogical and geochemical features observed in the transitional zones above and below the laterite ore in both the Nissi and Patitira (Lokris) Ni-laterite deposits. The upper transition zone is characterized by an association of framboidal pyrite with organic matter, and the lower zone by the occurrence of goethite, which differs compared to the common type of rounded and angular fragments of goethite and limonite containing detrital grains of quartz, chromite, and chlorite. These differ from typical goethite and limonite in many ways including (a) size, (b) shape, and (c) trace element content.The occurrence and association of Fe-mineral assemblages (pyrites and Fe-oxides) with fossilized microorganisms and the negative δ34S values for sulfide-bearing samples are indicative of organic matter involvement in the metal and metalloid cycling. The paucity of P, As, and REE within typical Fe-Ni laterite ore and the preferential occurrence of REE-minerals along with Ni, Co, and Mn (asbolane and silicates) towards the lowermost part of the laterite ore suggest their deposition was controlled by physicochemical conditions rather than the precursor rocks.

Behavior of Instrumented Omega Pile in Porous Soil

Results obtained from in-situ load tests carried out on omega displacement piles sunk in a porous, lateritic and unsaturated soil deposit, are analyzed in this paper. Three slow-maintained load tests were performed on deep instrumented piles with a diameter of 0.37 m and around 12 m long. The soil deposit consists of a superficial, silty clay “porous” layer 6 m thick. Under this layer there is a lateritic stratum 10 m thick, geotechnically consisting of a residual clayey silt. The results of the field load tests yielded a maximum pile load (average for the tests) of 1428 kN, which is twice as high as corresponding experimental values from standard bored piles with similar geometric conditions. Numerical finite element analyses, were performed in order to back-analyze the geotechnical soil parameters for a post-execution pile condition. The results permitted a better understanding of the improvement of the subsoil given the intrinsic execution characteristics of this particular pile. It was also possible to note that omega displacement piles have great potential to become an economically viable solution in tropical soils, given the enhanced behavior of such piles when compared to alternative techniques.

A Detailed Assessment of Global Nickel Resource Trends and Endowments

Research Article| November 01, 2014 A Detailed Assessment of Global Nickel Resource Trends and Endowments Gavin M. Mudd; Gavin M. Mudd † 1Environmental Engineering, Department of Civil Engineering, Monash University, Wellington Road, Clayton, VIC 3800, Australia †Corresponding author: e-mail, Gavin.Mudd@monash.edu Search for other works by this author on: GSW Google Scholar Simon M. Jowitt Simon M. Jowitt 2School of Geosciences, Monash University, Clayton, VIC 3800, Australia Search for other works by this author on: GSW Google Scholar Author and Article Information Gavin M. Mudd † 1Environmental Engineering, Department of Civil Engineering, Monash University, Wellington Road, Clayton, VIC 3800, Australia Simon M. Jowitt 2School of Geosciences, Monash University, Clayton, VIC 3800, Australia †Corresponding author: e-mail, Gavin.Mudd@monash.edu Publisher: Society of Economic Geologists Received: 05 Aug 2013 Accepted: 01 Feb 2014 First Online: 09 Mar 2017 Online ISSN: 1554-0774 Print ISSN: 0361-0128 © 2014 Society of Economic Geologists. Economic Geology (2014) 109 (7): 1813–1841. https://doi.org/10.2113/econgeo.109.7.1813 Article history Received: 05 Aug 2013 Accepted: 01 Feb 2014 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Gavin M. Mudd, Simon M. Jowitt; A Detailed Assessment of Global Nickel Resource Trends and Endowments. Economic Geology 2014;; 109 (7): 1813–1841. doi: https://doi.org/10.2113/econgeo.109.7.1813 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyEconomic Geology Search Advanced Search Abstract Nickel is a metal that reflects the technological advances of the twentieth and twenty-first centuries, emerging as critically important for stainless steel and a variety of specialty metal alloys as well as currency, chemicals, and batteries. Although mineral resources are commonly considered to be limited or finite, global Ni production has grown steadily throughout the twentieth century and has been matched by substantial growth in estimated Ni reserves and resources. While there is growing concern about “peak oil,” there is very little research about “peak minerals.” In this paper, we present a detailed compilation and assessment of globally reported Ni resources by project and split into standard mineral deposit types for the year 2011. The minimum amount of Ni reported globally as mineral resources is 296.2 million metric tons (Mt) Ni, split over a total of 253 sulfide projects containing 118.0 Mt Ni and 224 laterite projects containing 178.1 Mt Ni, with a further 3.38 Mt Ni in China (excluding Jinchuan, which is included in our sulfide compilation)—i.e., a global total of some 299.6 Mt Ni. Our data compilation indicates that the majority of global Ni resources are hosted by laterite deposits (59.5%), especially Ni laterite deposits located around the tropics. In addition, our compiled data indicate that global Ni resources continue to increase, despite a coincident increase in Ni production over time, along with declining cut-off and ore grades, increasing awareness of environmental issues and other related aspects. Overall, there are abundant Ni resources already identified which can meet growing global demands for some decades to come—the primary factors which govern whether a given project is developed (or not) will be social, economic, and environmental in nature. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Geotechnical Evaluation of Eastern Ghats Bauxite Deposits of India

Abstract: India is endowed with more than 3000 million tons of bauxite resources. Out of total India reserves, about 70% reserves are concentrated in Eastern Ghats (Odisha and Andhra Pradesh) region. Majority of the Eastern Ghat bauxite deposits are located at high altitude (high level type) and have been developed on khondalite and charnockite group of rocks with different geomorphological conditions. These are formed at an elevation of about 900-1400 meter above mean sea level (msl). The physico-mechanical and technological properties of these bauxite vary widely depending upon the parent rock composition, mode of origin, geomorphological position, duration and age of bauxite formation. In the Bayer process the most important parameter that decides the economic importance is the quality of bauxite which again decides the digestion parameters for alumina extraction. Jawaharlal Nehru Aluminium Research Development and Design Centre (JNARRDC) is in process of evaluating the bauxite and laterite deposits of India for its suitability for commercial applications. The present paper highlights the geological and geomorphological features of Eastern Ghats bauxite deposits and their technological characteristics. These studies are required to evaluate the bauxite in terms of their suitability for metallurgical and non metallurgical applications.