Laterite

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.

This article deals with a narrow zone of duricrusted escarpment and mesoscale badland landscape at Gangani on the right bank of Shilai river near Garhbeta in Medinipur district, West Bengal. Here the multilevel laterite duricrusts—formed either due to cyclic changes in water table or lateral migration of iron in an area of later relief inversion—have given rise to a 5-tier gully development producing a 5-facet landform assemblage. The regional slope evolution mostly resemble the 4-element slope retreat scheme of King, while both Hortonian and through-flow models can be applied to explain initiation of channels above the escarpment and at riverside confinement respectively. Lastly, probabilistic modelling suggests areal evolution of two gully networks by bifurcation at the tip and subsequent addition of tributaries. A note on implication of gully erosion is also added.

Distribution of lithofacies in vertical sequence, lateral extent and association of lithofacies characterize the basin fill sediments through alluvial fan to fan-delta sequence, exposed in the eastern parts of Ranjganj Coalfield (i.e. Ajay – Damodar Interfluve of West Bengal). The occurrences of Gci, Gcm and Gcg facies reflect clast-rich debris to pseudoplastic flow in hot and arid climatic condition on the faulted basal slope, situated at western shelf zone of Bengal Basin. Towards the proximal part, the sedimentary sequences of Gh, Gt, Gp, Fm, Sm and Gmg signify the progradation of fan-delta in hot and humid climatic condition under shallow marine environment. These facies of gravels were probably deposited in between Oligocene and Miocene when the monsoon climate was gradually established in this part of Peninsular India. This event was followed by intensive lateritization process, giving birth of autochthonous and allochthonous ferruginous materials since Late Miocene when the s...

Bolivia cubre en la parte oriental una región con una superficie de 220,000 km2 que corresponde a una pequeña parte del gran cratón Amazónico con afloramientos de rocas Meso-Proterozoicas (1.8-1.0 Ga). Aproximadamente diez por ciento de este regolito consiste de “esquistos” de metamorfismo bajo a medio. Investigaciones de los últimos veinticinco años demostraron que estos se presentan en Guarayos y la Chiquitania con características de cinturones de rocas verdes con potencial geológico importante para depósitos de oro orogénico y yacimientos de sulfuros masivos volcanogénicos (VMS). En este contexto el descubrimiento del depósito VMS “Miguela” hace veinte años representa un hallazgo bastante importante en la exploración minera del oriente Boliviano. Está hospedado en una secuencia volcano-sedimentar con afinidad toleítica dentro del cinturón de rocas verdes de Guarayos. Los estudios regionales del pasado no tomaron en cuenta la búsqueda sistemática para este tipo de depósitos, tampoco la aplicación de métodos innovadores de exploración para permitir el descubrimiento de cuerpos mineralizados que no afloran y no dejan rasgos en superficie. Los sulfuros masivos de “Miguela” están ligados a la formación “La Pastora”, que se extiende sobre una distancia de por lo menos doce kilómetros. Los tres lentes mineralizados son ricos en cobre y oro. La mineralización se formó como precipitación submarina e impregnación dentro de los sedimentos y rocas volcánicas con un control por una falla sin-volcánica.

The purpose of this study is to determine the properties of laterite soil and how they affect the stability of bitumen stabilized bricks. The samples for the study were disturbed samples sourced in seven locations in Adamawa State. Each sample weigh 20kg transported to the laboratory for tests. The tests conducted include: Sieve Analysis, sedimentation Test, Liquid Limit Test, Plastic Limit Test, Activity Ratio, Free Swell Test and Optimum Moisture Content Test. Three research questions guided the study and the findings of the study include; that the samples shows increase percentage smaller or less than 63 microns sizes, which indicate that the samples are more of silt and clay particles. The properties of the laterite soils taken for the study include; liquid limit ranging from 35-49, plasticity index from 11-14 percent, the activity ratio ranges from 1.0-1.4, and free swell test shows less than 100 percent. One of the recommendations made was that, Laterite soil stabilization should precede a study of the particles size distribution to ensure that the categories of the Laterite soil can bland with the bitumen emulsion to envelop the particles for the purpose of preventing moisture movement in the bricks.

It is quite impossible to travel far in India without observing the remarkable ferruginous crust to which F. Buchanan in 1807 gave the name of laterite. In Indian peninsula it is a post-Cretaceous stratigraphic succession with polycyclic nature of evolution which marks the unconformity with Recent Quaternary Alluvium. There are perennial problems and research gaps in the investigation of laterites in India as well as West Bengal -(1) defining, indentifying and classifying lateritic materials,

It is quite impossible to travel far in India without observing the remarkable ferruginous crust to which F. Buchanan in 1807 gave the name of laterite. In Indian peninsula it is a post-Cretaceous stratigraphic succession with polycyclic nature of evolution which marks the unconformity with Recent Quaternary Alluvium. There are perennial problems and research gaps in the investigation of laterites in India as well as West Bengal – (1) defining, indentifying and classifying lateritic materials, (2) mode of formation of laterite and its other horizons, (3) determining the ages of laterites, (4) reliability of laterites as palaeoclimatic indicators, (5) identifying topographic requirements and pedo-geomorphic processes for laterite formation and (6) reconstructions of former lateritized landscapes. The formation of north – south lateritc cover (i.e. Rarh Bengal) on the Rajmahal Traps, Archaean granite – gneiss, Gondwana sedimentary, Paleogene gravels and Old Deltaic Alluvium is analyzed here to resolve the aforesaid problems and to depict the variable characteristics of laterites with special reference to its tectono – climatic evolution in northwest marginal part of the Bengal Basin. This paper reveals that the low-level secondary laterites (probably Pliocene – Early Pleistocene age) of Rarh Bengal are composed of heterogeneous iron – aluminum rich gravelly materials which were derived from the high-level primary laterites (probably Eocene – Miocene age) of Plateau since Paleogene Period by the peninsular river system, following the underlying structure of the Bengal Basin. Alongside the roles of drifting of Indian Plate, establishment of monsoon climate, neo-tectonic uplifts and re-lateritisation of ferruginous shelf deposits are determined here to unearth the palaeogenesis of primary and secondary laterites in West Bengal.

In a raised Pleistocene terrain, 2 km northwest of Santiniketan, West Bengal (23°41'50"N, 87°40'8"E), active gullying and escarpment retreat were initiated after excavation of an escape-channel in 1953. The area is partly capped by loosely aggregated laterite, probably developed in situ with additional contributions from upland sources. Hollow lateritic nodules and allochthonous petrified woods of genera Cynometroxylon, Milletioxylon and Palmoxylon are common in the region. An erosion survey between November, 1989 and February, 1993 has revealed that, in response to 4316 mm of rainfall, the average rates of gully extension, surface lowering and escarpment retreat were 16.1 cm/yr , 0.4 cm/yr and 21.7 cm/yr respectively in laterite capped areas and 33.9 cm/yr, 1.6 cm/yr and 40 cm/yr in non-lateritic areas. The landform units of the area can be classified according to their position in the cross-sectional profile. However, attainment of a mature badland topography has been successfully prevented by afforestation.

Indonesia merupakan salah satu negara yang memiliki iklim tropis, memiliki dua musim saja yaitu musim hujan dan musim kemarau. Indonesia adalah  negara yang memiliki zona geologi yang komplek sebab indonesia terletak di tepi bagian tenggara benua eurasia,indonesia sendiri berbatasan dengan zona tektonik yang aktif di tandai dengan tingginya tingkat terjadinya gempa. Sedangkan sulawesi sendiri di bentuk oleh tiga lempeng utama yaitu zona konvergensi kompleks Eurasia, Pasifik dan lempeng kerak Australia. (Badaru dkk,2019). Hal ini menyebabkan terjadi proses vulkanik tektonik salah satunya menyebabkan adanya potensi panas bumi. (Manyoe,2020). Salah satu potensi geotermal terdapat di gorontalo yaitu pada daerah Bongongayu (Manyoe,2018). Analisis geomorfologi juga selalu dalam pemetaan bentang alam vuklanik. (Handayani,2015).
Pada daerah timur indonesia khususnya memiliki kompleks ofiolit yang biasa disebut dengan lajur ofiolit. Batuan yang mengandung nikel biasanya terdapat pada peridotit dan serpentinit yang terbentuk pada proses pelapukan di daerah tropis yang sangat intensif. (Hasria,2019).
Batuan yang mengalami pelapukan dan terolah baik secara kimia akan mengahasilkan endapan nikel laterit. Batuan yang menghasilkan endapan nikel laterit biasanya terdiri dari batuan ultramafik seperti dunite,harzburgit,lhierzolit,serpentinit,piroksenit,websterit dan wehrlit. Batuan mafik juga termasuk seperti basalt dan gabro. Pengkayaan supergen merupakan unsur-unsur logam yang terkandung dan mengalami leahing serta terkonsentrasi ke dalam satu zona atau lebih. Pengkayaan menyebabkan batuan ultramafic yang banyak mengandung Ni mengalami proses kimia serta kontak dengan air permukaan atau air tanah sehingga mengalami proses pengkayaan mineral berat seperti Ni,Fe dan lainnya.(Waluyo).

SUMMARY: By their mode of formation, laterites and lateritic soils can be sensitive to the method of drying and also to manipulation. The extent of sensitivity to drying and to breakdown on manipulation depends on the weathering conditions. Compaction is perhaps the most common soil improvement technique. Many of the properties of soil such as shear strength and compressibility characteristics as well as erodibility potential depend on the level of compaction at which the soil is placed. Laboratory compaction testing is done to provide parameters for quality control during field compaction. However, for some lateritic soils, the method of preparation of the soil samples before compaction can influence the compaction characteristics to various extent. The study reported is part of a larger study of effect of sample preparation methods on local lateritic soils currently going on in our Geotechnical group. Samples of a local lateritic soil were prepared by oven drying, air-drying and in its natural condition. Standard Proctor compaction was used in determining the compaction characteristics for each method of drying from which the water content dry density relationship was obtained. The paper discusses the differences in the compaction characteristics due to the effects of the methods of preparation of the samples and the effect on particle breakage.

Lateritic soils at Otun Ekiti, Ekiti state, southwestern Nigeria were investigated with respect to their geotechnical properties and their suitability for subgrade and subbase construction materials. Four disturbed lateritic soil samples (sample A, B, C and D) were selected for the various laboratory techniques. The grain size analyses, the specific gravity tests, the atterberg limit tests, compaction, California bearing ratio and shear box tests were carried out on the samples. The grain size analysis shows that sample A is gravelly silt-clayey sand. Sample B is siltclayey gravel composition. Sample C is gravelly silt-clayey while Sample D is silt-clayey gravel. Atterberg consistency limit test indicate that sample A has 30.0%, liquid limit 19.5% plastic limit, 10.5% plasticity index, 9.1% shrinkage limit. Sample B has liquid limit of 27.0%, 16.2% plastic limit, 10.8% plasticity index and 7.4% shrinkage limit. Sample C has a liquid limit of 32.4%, plastic limit of 15.6%. It has a plastic index of 16.8%, Shrinkage limit of 9.7% while Sample D has a liquid limit of 36.2%, plastic limit of 17.7%. It has a plastic index of 18.5% and 11.1% as shrinkage limit. Thus, the soil is classified to be intermediate plasticity which can be used for subgrade and subbase materials. The soil samples are above the activity (A) line in the zone of intermediate plasticity (CL) which suggests that they are inorganic soils. Based on engineering use chart, the workability as construction engineering is good to fair particularly as erosion resistance in canal construction. However, the high shrinkage limit may also reduce erosion in this area because of cohesion of the plastic clay material. The California Bearing Ratio (CBR) values are within 2-3% (mean = 2.75%) and 2-4% (mean = 2.75%) in sample A and sample B respectively while California Bearing Ratio (CBR) of 2-4% (mean = 2.75%) and 2-3% (mean = 2.75%) in sample C and sample D respectively. This implies that the materials can be used as a sub-grade to base course material for support of flexible pavements. The compaction tests for the optimum water content for sample A is 15.0% and 13.0% for standard and modified proctor respectively. The standard and modified proctor

This research determined the geotechnical properties of lateritic soil modified with sugarcane straw ash with a view to obtaining a cheaper and effective replacement for the conventional soil stabilizers. Preliminary tests were performed on three samples, A, B and C for identification and classification purposes followed by the consistency limit tests. Geotechnical strength tests (compaction, California bearing ratio (CBR), unconfined compression test and triaxial) were also performed on the samples, both at the stabilized and unstabilized states (adding 2, 4, 6, and 8% sugarcane straw ash). The results showed that sugarcane straw ash improved the geotechnical properties of the soil samples. Optimum moisture content increased from 19.0 to 20.5%, 13.3 to 15.7% and 11.7 to 17.0%, CBR increased from 6.31 to 23.3%, 6.24 to 14.88% and 6.24 to 24.88% and unconfined compression strength increased from 79.64 to 284.66kN/m 2 , 204.86 to 350.10kN/m 2 and 240.4 to 564.6kN/m 2 in samples A, B and C respectively. Sugarcane straw ash was therefore found as an effective stabilizer for lateritic soils.

Each geomorphic hazard involves a degree of risk which incorporates quantification of the probability
that a hazard will be harmful. At present, the categorization of sub-watersheds into erosion risk is considered
as the fundamental step to conserve the soil loss. Development of badlands over the laterites of
Birbhum district is an indicative of excessive soil loss in the monsoonal wet-dry type of climate. Slope
erosion and channel erosion have generated huge amount of sediment from the small watersheds during
intense monsoonal rainfall (June–September). The adjoining areas of Rampurhat I Block, Birbhum
(West Bengal) and Shikaripara Block, Dumka (Jharkhand) have lost the lateritic soil cover at a rate of
20–40 ton/ha/year (Sarkar et al. 2005). In order to estimate the progressive removal of soil particles from
the gully-catchments of the above-mentioned area, different morphometric parameters, soil parameters,
hydrologic parameters and empirical models are employed. Side by side, the study is carried out to categorize
the gully-catchments into different magnitude of erosion risk using several multivariate statistical
techniques.

Global resources of heavy Rare Earth Elements (REE) are dominantly sourced from Chinese regolith-hosted ion-adsorption deposits in which the REE are inferred to be weakly adsorbed onto clay minerals. Similar deposits elsewhere might provide alternative supply for these high-tech metals, but the adsorption mechanisms remain unclear and the adsorbed state of REE to clays has never been demonstrated in situ. This study compares the mineralogy and speciation of REE in economic weathering profiles from China to prospective regoliths developed on peralkaline rocks from Madagascar. We use synchrotron X-ray absorption spectroscopy to study the distribution and local bonding environment of Y and Nd, as proxies for heavy and light REE, in the deposits. Our results show that REE are truly adsorbed as easily leachable 8-to 9-coordinated outer-sphere hydrated complexes, dominantly onto kaolinite. Hence, at the atomic level, the Malagasy clays are genuine mineralogical analogues to those currentl...

ÖZET: Kaletepe lateritik boksit zuhurunda y a k l a ş ı k 3 km yanal olarak devam eden l a t e r i t i k boksit kuşağı bulunmaktadır. Lateritik boksitler Hacıalabaz formasyonunun, İslikayatepe dolerit üyesine ait üç dolerit seviyesinin ayrışması ile oluşmuş stratigrafik kontrollü zuhurlardır. Kuşağın kalınlığı 30-80 m arasında olup, yanal yönde yer yer faylarla kesilme veya genç formasyonlarla örtülmeler d ı ş ı n d a devamlıdır. Doleritler, kıta içi bazik magma ürünü kayaçlardır.

Laterite karst is a special type of silicate karst (formed in silicate rocks such as sediments or granite) that in turn is a type of parakarst (solution of non-carbonate rocks). However, the chemical and physical processes involved in the formation of laterites, and deep weathering profiles in general, are quite complex.

Distribution of lithofacies in vertical sequence, lateral extent and association of lithofacies characterize
the basin fill sediments through alluvial fan to fan-delta sequence, exposed in the eastern parts of
Ranjganj Coalfield (i.e. Ajay – Damodar Interfluve of West Bengal). The occurrences of Gci, Gcm and
Gcg facies reflect clast-rich debris to pseudoplastic flow in hot and arid climatic condition on the faulted
basal slope, situated at western shelf zone of Bengal Basin. Towards the proximal part, the sedimentary
sequences of Gh, Gt, Gp, Fm, Sm and Gmg signify the progradation of fan-delta in hot and humid
climatic condition under shallow marine environment. These facies of gravels were probably deposited in
between Oligocene and Miocene when the monsoon climate was gradually established in this part of
Peninsular India. This event was followed by intensive lateritization process, giving birth of
autochthonous and allochthonous ferruginous materials since Late Miocene when the shoreline was
finally receded from this part. The ferruginous beds of clast-rich Tertiary gravels (fan lobes) are identified
as a signature of earliest coarse deposits in the north-west Bengal Basin, carrying proxies of
palaeomonsoon.

Gully erosion and parallel retreat of slope in a duricrust-capped terrain are commonplace the world over, and at many places they are man-initiated. This article deals with such an area near Santiniketan, West Bengal. Attaining fast rate of retreat, the scarp-like banks of a 1953 overspill channel have receded at a rate of 12.12 centimetres per annum. Moreover, their slope configuration has also shown a deviation from the four element parallel retreat model, generally the most applicable one to duricrusted areas, by not showing one of its characteristic elements—the crest slope. The article suggests that this may occur due to superposition of a previously formed facet during excavation of the channel. In this connection it also tries to explain evolution of a particular gully formed in the region

This Brief analyses and discusses the laterites in the Bengal Basin. The book highlights: (1) the definition, identification and classification of ferruginous materials, (2) the mode of laterite formation and its other horizons, (3) processes and theories of lateritisation, (4) determination of laterite ages, (5) recognition of palaeogeomorphic and palaeoclimatic significance and (6) geo-chronology and reconstruction of former lateritized landscapes. The chapters cover the tectono-climatic evolution of north-south laterite profiles of the north-western Bengal Basin on the Rajmahal Basalt Traps, Archean Granite-Gneiss, Gondwana Sandstones, Palaeogene Gravels and Older Palaeo-Deltaic Alluvium. The book uses advanced field-based studies, quantitative analysis and thematic mapping to cover various areas of palaeogeography and regolith geology of the Bengal Basin in connection with laterite genesis, palaeoweathering, tectonic geomorphology, Quaternary geomorphology and pedogeomorphology. It introduces laterites as a potential stratigraphic marker in Indian geology by explaining their palaeogeomorphic and palaeoclimatic significance.

This Brief is a comprehensive resource to researchers, students and academicians of geography, geomorphology and geology working on laterites.

This project is an in-depth investigation of the geotechnical engineering properties of subgrade and base soils used in the construction of Omolayo Road in Akobo Area of Lagelu local government, Oyo State, Nigeria. Subgrade samples were collected at chainages 0+000, 1+000, 2+000, 3+000 and 4+000 respectively at depths ranging 0.5m to 1.0m, while the base sample was collected from one of the heaps of laterite brought from the borrow-pit at Oluwo area along New Ife Express Road, Oyo State, Nigeria. The samples were subjected to the following laboratory tests; Particle (grain) size analysis, Atterberg limit test, Compaction test, California bearing ratio (CBR) test and Specific gravity test. The particle size analysis results showed that all samples, both subgrade and base were well graded since their Uniformity Coefficients were greater than 15. It further revealed that base sample were more plastic compared to subgrade samples since it has highest percentage of clay passing sieve no. 200 (75µm) i.e. 27.60%. This indicates that samples with high silt clay content are susceptible to volume changes when wet. The liquid limit and plastic index range from 24% to 48% and 2.7% to 25% respectively with base sample having the highest in both cases. This shows that base sample has high clay content and its load bearing capacity could be reduced when wet. The maximum dry densities ranged from 1.90mg/m 3 to 2.19mg/m 3 and Optimum moisture contents range from 5.4% to 14.2% respectively. The California bearing ratio is from 78% to 132% (unsoaked). The Specific gravity results ranged from 2.65 to 2.68. The samples were classified using AASHTO classification. The AASHTO system classified the subgrade samples as A-1-b and A-2-4 constituting 50% and 33.3% respectively, and base sample classified as A-2-7 constituting 16.6%. This shows the subgrade samples are excellent to good while base sample is fair to poor.

This project is an in-depth investigation of the geotechnical engineering properties of subgrade and base soils used in the construction of Omolayo Road in Akobo Area of Lagelu local government, Oyo State, Nigeria. Subgrade samples were collected at chainages 0+000, 1+000, 2+000, 3+000 and 4+000 respectively at depths ranging 0.5m to 1.0m, while the base sample was collected from one of the heaps of laterite brought from the borrow-pit at Oluwo area along New Ife Express Road, Oyo State, Nigeria. The samples were subjected to the following laboratory tests; Particle (grain) size analysis, Atterberg limit test, Compaction test, California bearing ratio (CBR) test and Specific gravity test. The particle size analysis results showed that all samples, both subgrade and base were well graded since their Uniformity Coefficients were greater than 15. It further revealed that base sample were more plastic compared to subgrade samples since it has highest percentage of clay passing sieve no. 200 (75µm) i.e. 27.60%. This indicates that samples with high silt clay content are susceptible to volume changes when wet. The liquid limit and plastic index range from 24% to 48% and 2.7% to 25% respectively with base sample having the highest in both cases. This shows that base sample has high clay content and its load bearing capacity could be reduced when wet. The maximum dry densities ranged from 1.90mg/m 3 to 2.19mg/m 3 and Optimum moisture contents range from 5.4% to 14.2% respectively. The California bearing ratio is from 78% to 132% (unsoaked). The Specific gravity results ranged from 2.65 to 2.68. The samples were classified using AASHTO classification. The AASHTO system classified the subgrade samples as A-1-b and A-2-4 constituting 50% and 33.3% respectively, and base sample classified as A-2-7 constituting 16.6%. This shows the subgrade samples are excellent to good while base sample is fair to poor.

This paper presents the effect of abundantly available fly ash, on the index properties namely liquid and plastic limit and compaction characteristics of shedi soil. Shedi soil is a problematic soil that lies between top low level laterite and bottom high level laterites in the western coastal area of Karnataka, India. The effect of sodium salts on this shedi soil optimized with Neyveli Fly ash has also been studied. Considerable changes in the index properties and compaction characteristics were observed which are explained based on series of experimental results. Addition of Neyveli fly ash improved the workability of shedi soil considerably. The addition of sodium sulphate to the optimum combination of shedi soil-Neyveli fly ash mixture increases the shear strength of the mixture. The maximum dry density also found increased with the addition of sodium sulphate.

This project is an indepth investigation of the ge otechnical engineering properties of subgrade and base soils used in the construction of Omolayo Road in Akobo Area of Lagelu local government, Oyo State, Nigeria. Subgrade samples were collected at chainages 0+000, 1+000, 2+000, 3+000 and 4+000 respectively at depths ranging 0.5m to 1.0m, while the base sample was collected from one of the heaps of laterite brought from the borrowpit at Oluwo area along New Ife Express Road, Oyo State, Nigeria. The samples were subjected to the following laboratory tests; Particle (grain) size analysis, Atterberg limit test, Compaction test, California bearing ratio (CBR) test and Specific gravity test. The particle size analysis results showed that all samples, both subgrade and base were well graded since their Uniformity Coefficients were greater than 15. It further revealed that base sample were more plastic compared to subgrade samples since it has highest percentage of clay passing sieve no. ...

Administratively, the research area is located in PT. Vale Indonesia Sorowako region, District of Nuha, Luwu Timur Regency, Province of South Sulawesi This research is aimed to determine the grains size of soil with the content of the elements Ni, Fe, and S / M high in the zone of saprolite-type west block and east block, know the grains size of soil with with the content of the elements Ni, Fe, and S / M were lower in the saphrolite zone type west block and east block, and determine the ratio and the effect of soil grain size in improving the quality levels of Ni, Fe and S / M with analysis XRF method.
Based on research gained 30 sample <25.4 mm of west block and east block type. Each sample then preparated become 7 grain size. The 7 grain size are >6.35 mm, <6.35 – 1.67 mm, <1.67– 0.14 mm,  <0.14 – 0.10 mm, <0.10– 0.07 mm, and <0.07 mm. In type deposition west block, the highest concentration of Ni elements found in the grain size of <0.10 to 0.07 mm that is equal to 2.47%; levels of the elements Fe and SiO2 / MgO (S / M) is the highest found in the grain size of <0.07 mm is equal to 26.57% Fe and 3.11% of the elements on the levels of SiO2 / MgO (S / M). In type deposition east block, the highest concentration of Ni elements found in the grain size of <0.14 to 0.10 mm mm that is equal to 2:04%; The highest levels of Fe element found in grain size <0.07 mm is equal to 28.38%; and levels of SiO2 / MgO (S / M) is the highest found in the grain size of <0.10 to 0.07 mm mm that is equal to 2.4%. In type deposition west block, the levels of the elements Ni, Fe element, and SiO2 / MgO (S / M) the lowest common in grain size >6.35 mm is $ 1.41% for the elements Ni, 10.72% for the elements Fe, and 2.4 % for SiO2 / MgO (S / M). In type deposition east block, the levels of the elements Ni, the elements Fe and SiO2 / MgO (S / M) the lowest common in grain size >6.35 mm is equal to 1.65% for the elements Ni, 13.9% for the elements Fe, and 1.67% for SiO2 / MgO (S / M). There is an opportunity to increase levels of Ni element is to remove material ¼ mesh size fraction. The increase in Ni element in the area of West block of 7% by weight lost by 17.81. In the area of East block of 3% by weight of the weight lost by 17:49%.

Urban stormwater runoff carries sediment and contaminants from impervious layers like streets, pavements etc. Stormwater reaching out into the surrounding clean water increases the concentrations of turbidity, suspended solids concentration, and other water quality parameter. The conventional method to remove the pollutants from water is to pass it through the porous filter media. The common porous media are sand, char coal, anthracite, activated carbon, etc. The Laterite soil is one such naturally available porous media from which the pollutants will be removed due to its porous and permeable nature, adsorption and ion exchange capacity. Geo-textile is synthetic material having high water permeability which helps in removal of larger suspended particles, oil and grease. The present research work is focused on performance evaluation of Laterite soil as single filter media and Laterite-Geo Textile as dual filter media for treating urban runoff water. This is a novel technique for reclamation of urban stormwater runoff and groundwater recharge. Residential pavement and Mechanical shop pavement flush water is used as an artificial urban stromwater runoff sample. Laterite media and Laterite-Geo Textile media were efficient in reducing turbidity by 90% and 92% at 25mL/min flow rate respectively for residential pavement runoff water. Similarly Total hardness, Nitrate, Iron and Fluoride was as also significantly reduced in both the runoff water. Laterite media and Laterite Geo textile media proved to be effective in removal of the considered parameters.

Gully erosion signifies instability in the landscape, and it is regarded as a threshold phenomenon under certain conditions in the landscape, relating to flow erosivity and surface resistance. The main cause of gully formation is too much water at a certain location of slope-a threshold condition that may be brought about by external factors or internal factors. Intense rainfall is the primary trigger, but the local conditions such as slope morphome-try, land-use and soil characteristics control the triggering of gully erosion. The catchment size above a stream or gully head and the land-use characteristics determine the volume of overland flow but it is different from the concentrated-flow area by its position on the slope. In the present study, the models of geomorphic threshold and the M-D Envelope have emphasized on the role of overland flow (as surface runoff) for initiation of gullies in the laterite slope of Dwarka-Brahmani Interfluve, West Bengal (Neogene-Early Pleistocene lateritic terrain located in between the Rajmahal basalt traps and Bengal basin). The upstream laterite slopes above gully heads are negatively correlated (r ¼ 0.55) with upstream drainage areas which are used as surrogate for the volume of runoff yield in the gullies of the study area. The calculated empirical trend line (S ¼ 17.419 A 0.2517 , with R 2 of 0.52) represents an approximation to critical slope-area threshold relationship for gully incision in this region. Then, the Soil Conservation Service-Curve Number (SCS-CN; now called the National Resource Conservation Service, NRCS-CN) method is used for quick and accurate estimation of surface runoff in any storm event in the ungauged watersheds of gullies. Experimenting in three sample watersheds of gullies, it is found that on the basis of rainfall range of 42-137.2 mm the gullies can yield runoff of 40.02-118.0 mm in excess moisture condition of monsoon. The differences of runoff in the catchments for the same rainfall event are the direct effects of land use-land cover derived from CN values. In the gully catchments, the estimated runoff is increased above 22% from Antecedent Moisture Condition (AMC) II to AMC III and in most gullies it ranges from 22.33% to 85.73%. It is understood that if the rainfall amount is increased day by day, the runoff coefficient (R c) is also increased consecutively and it will be high runoff event which is the sign of high vulnerability of flow erosion on the bare laterite slope. The SCS-CN analyses reflect that in prolong rainfall event of tropical depression more than 86% of rainfall can be transformed into direct runoff, as R c is reaching up to 0.86. Alongside, it gives more hydraulic energy to gully initiation and gully head migration in AMC III condition. Based on the daily rainfall-runoff modelling and annual potential erosion rate, the estimated sediment yield varies from 5.0 to 13.45 t ha 1 in the gullies. It is learnt that in prolong rainstorm event or in cyclonic rainfall, with increase of rainfall and moisture content of surface, the transport of eroded materials is increased and substantially, the sediment yield of gully catchment is also escalated.

The increasing demand for Rare Earth Elements (REE) is related to the continous development of technology , and these elements are used in modern equipments. REE can occur in igneous and sedimentary rocks in significant amounts as primary deposits, whereas the secondary REE deposit can be produced by intensive lateritic weathering of bedrocks under the tropical or subtropical climate. Lateritic process can increase REE concentration from sub-economic levels in host rocks to be more valuable. Muncung Granite is located in a tropical area of Lingga Regency, Riau Islands Province. REE occurs in the Muncung Granite and in weathered layers (saprolite, laterite, and soil). ICP-MS was applied to measure the REE content in all samples of this study. The average REE content of the Muncung Granite is 265 ppm with Eu anomaly in REE's spider diagrams. Lateritization process has increased REE content by more than four times compared to that in the Muncung Granite. Ce and Eu anomalies in weathered layers can be associated with weathering process and initial REE contents in the host rock. Ce anomaly in a laterite layer is found to have a negative correlation to REE total enrichment. The REE level in the Muncung Granite is higher than the content in the soil and saprolite layers, but lower than that in the laterite.

Global resources of heavy Rare Earth Elements (REE) are dominantly sourced from Chinese regolith-hosted ion-adsorption deposits in which the REE are inferred to be weakly adsorbed onto clay minerals. Similar deposits elsewhere might provide alternative supply for these high-tech metals, but the adsorption mechanisms remain unclear and the adsorbed state of REE to clays has never been demonstrated in situ. This study compares the mineralogy and speciation of REE in economic weathering profiles from China to prospective regoliths developed on peralkaline rocks from Madagascar. We use synchrotron X-ray absorption spectroscopy to study the distribution and local bonding environment of Y and Nd, as proxies for heavy and light REE, in the deposits. Our results show that REE are truly adsorbed as easily leachable 8-to 9-coordinated outer-sphere hydrated complexes, dominantly onto kaolinite. Hence, at the atomic level, the Malagasy clays are genuine mineralogical analogues to those currentl...

Stratigraphic, geomorphological, and radiometric evidence shows that the laterite of the high plains and plateau of Kangaroo Island is older than the Middle Jurassic but younger than the Early Permian. Palaeoclimatic and palaeontological considerations suggest the Triassic as the most likely age of both the laterite and the surface on which it is developed. High-level lateritized surfaces in the adjacent Mount Lofty Ranges and southern Eyre Peninsula are of similar age.

The North Konawe Regency, located in the northern part of the southeast arm of Sulawesi Province, is occupied mainly by Ophiolite Complex. Recent studies on weathering of ultramafic complex have been focussed on the composition of laterite in relation to heavy metal explorations. In Asera area, North Konawe, a 3.1 m wide outcrop of ultramafic rocks is related to nickel laterite potential. In this study, an elemental change during the weathering process is discussed, including the mobilization of rare earth elements. XRF and ICP-MS from The Centre for Geological Survey of Indonesia are the two important geochemistry instruments used in this study. Si, Mg, and Ca are depleted during weathering, whilst the enriched elements are Fe, Al, Ti, and some heavy metals such as Cr, Mn, and Co. A different mobilization pattern is detected on Ni, because of its relation to Mg. Cs, Rb, and Ba are concentrated in a clayey horizon of upper laterite. The increase of REE concentrations is parallel to both Fe and Mn which rises to the top of laterite. Ce and Eu negative anomaly trends indicate oxidizing condition through the weathering process, although the studied profile, influenced by allochthon material, morphology condition, and geochemistry composition, indicates that the transported rock fragments were originated from ultramafic rock.

This study used eco-friendly materials known as Periwinkle Shell Powder (PSP) in stabilizing the engineering properties of lateritic soil. Preliminary test was performed on the un-stabilized lateritic soil for the purposes of identification and classification (natural moisture content, liquid limits, plastic limits, and plasticity index). The engineering tests were conducted on the lateritic soil stabilized with additions of (2, 4, 6, 8 and 10 %) PSP and OPC respectively. The result showed that cement gave a progressive increase in the Maximum Dry Density (MDD) of the lateritic soil from 1875 kg/m3 (2 %) to 2294 kg/m3 (10 %) respectively. This represents 22 % increase in the MDD from the un-stabilized state. For PSP, the Maximum MDD was attained at 6 % (1974 kg/m3), representing 5.3 % increase in MDD of the soil from the un-stabilized state. For both stabilizing agent, the Optimum Moisture Content (OMC) increases from 13.65 % to 13.83 % and from 11.72 % to 14.41 % for Cement and Periwinkle Shell Powder respectively. PSP recorded an increase of 5.6 % of CBR value compared with OPC that recorded an increase of 34 % CBR value. The study therefore concluded that Periwinkle Shell Powder (PSP) could be considered as good stabilizer for clayey or lateritic, and its uses as a stabilizer could also provide a big relief to the environmental pollution caused by its indiscriminate dumping.

Laterites of Birbhum district are indentified as the ‘low-level laterites’ of ‘Rarh Plain’ of West Bengal and these are very much prone to severe soil erosion (mainly surface and sub-surface water erosion) in the monsoonal season (June - September.) Laterites and lateritic soils (locally named ‘Kankara’) of Caniozoic upland (adjoining areas of Rampurhat I block, Birbhum and Shikaripara block, Dumka- the study area), are the direct result of monsoonal wet-dry type of morpho-climatic processes and further laterisation of fluvial deposited materials (formation of surface duricrust) which was coming from Rajmahal Hills of eastern Chotanagpur Plateau (Jharkhand) in late Pleistocene. Such type of vermiform laterites is shaped and dissected by numerous gullies and ravines, giving birth of badland topography (locally named ‘Khoai’) of both degradation and aggradation processes. Before the soil conservation practices it is helpful if the assessment of soil erosion can be transformed into a statement of how fast soil is being eroded. The estimation of rate of annual soil loss is required in that case, because we must have to predict soil loss through effective models under a wide range of conditions. In this study the entire assessment is focused on the application Universal Soil Loss Equation (USLE) and Morgan, Morgan and Finney (MMF) methods in the soil loss estimation of sample slope segments, and relative comparison and suitability of both methods in the precise estimation of predicting soil loss.

An increase in construction and material use in tropical environments has made way for engineering knowledge of related basic properties of soils within those areas. One such soil found abundantly are the laterite soils. This study is based on determining the engineering geotechnical properties of laterite soils which are observed to occur in the town of Nilai, Malaysia. These basic properties were generally determined for nonproblematic laterite soils. Experimental analysis of earlier research as well as related journals on the same subject were reviewed. Five sites were randomly chosen throughout Nilai from which disturbed and undisturbed laterite soil samples at a depth of 1m were collected. The objectives of this study were satisfied by a series of standardized tests done on the soil using laboratory equipment. Comparison of the determined engineering properties were compared with properties of similar studies done on laterite soils found in parts of the world. The findings show...

The traditional production of stainless steel follows a long-way process which requires high energy consumption and increase emissions of CO and CO2 gases. This study aimed at assessing isothermal reduction smelting of additional mixed samples of chromite/laterite ores to produce directly Fe-Cr-Ni metal alloys in a single route manner. Chromite and laterite ores were obtained at Zambales and Surigao del Norte provinces, Philippines. Isothermal smelting was conducted to samples, 6/94 and 35/65 in addition to 12/88, 25/75 and 50/50, with coconut charcoal as reductant under argon atmosphere at 1600 ºC in one hour under a vertical electric arc furnace. Higher Cr contents are obtained at increasing percentages of chromite in the mixtures. Ni contents are in fluctuations at increasing laterite contents. Cr and Ni contents can be greatly attributed to the high dilution activity of iron in the metals. Higher recoveries of metal alloys are manifested at smelting 6/94, 35/65 and 50/50 with 93.67, 95.91 and 99.62%, respectively, at increasing chromite compositions. On the other hand, recoveries are decreasing at increasing laterite contents, clearly shown after smelting 12/88 and 25/75 samples with 69.70 and 78.99%, from that of 35/65 with 95.91%. The flushing out of volumes of slag, which is directly related to slag foaming, is believed to be the reason of the said decreasing recoveries. It can be recommended to use other carbon-based reductants and assess their impacts on the recovery of the metal alloys and on their Cr and Ni contents. Exploring other combinations of Philippines chromite and laterite can also be considered accounting their potential to obtain higher recoveries and higher Cr and Ni contents in the metal alloys. Slag foaming can also be further studied with parameters in this direct route smelting

Peringave Landslide had happened on 15th August 2018 and had lead to death of nine individuals. The field visit explored the reasons for such an incident which without any mining activity would have been a safe place to live. the Laterite and Charnokite quarrying has made deep scars and if actions are not taken now more such incidents are likely to happen in the future.

The investigation carried out in this paper was to evaluate the effect of eggshell powder and sodium silicate as stabilizers to laterite soil used as fill material for the purpose of constructing light traffic pavement. The laterite soil used in this study was collected from Ikorodu North Local Government Area in Lagos State, Nigeria and treated with eggshell powder (ESP) and sodium silicate (SS) blend in stepped concentrations of 3% ESP + 2% SS, 6% ESP + 4% SS, 9% ESP + 6% SS, 12% ESP + 8% SS and 15% ESP + 10% SS by dry weight of the soil. Results from the tests carried out showed a general improvement on the engineering properties of the laterite treated with ESP and SS blend. Optimum California Bearing Ratio (CBR) tests results for un-soaked and soaked samples were recorded as 51% and 22% at 12% ESP + 8%SS content. Peak Unconfined Compressive Strength (UCS) values of 355 KN/m2 and 570 KN/m2 were recorded at 7- and 28-days curing periods respectively at an optimum blend of 12% ESP...

Laterite is one of the major materials used in highway pavement construction in Nigeria. Its properties are affected by some environmental factors which may make it unsuitable for highway pavement construction. This research was aimed of investigating the effect of pH on geotechnical properties of Laterite soil used in highway construction. Laterite soil sample was collected from a burrow pit at LAUTECH and it was sun dried for about 24 hours and then soaked in different pH solutions (pH =3.0, pH=5.0, pH = 7.0 and pH = 9.0) using diluted tetraoxosulphate (vi) acid (H2SO4) and ammonia. The container was perforated at the bottom in order simulate the actual field condition. The