Grades Of Ores Research Articles

Mathematical Analysis of the Effect of Iron and Silica on the Reduction Performance of Manganese Ores

In the current study, a factorial design is used to investigate the effect of total iron and silica on the metallurgical performance of different grades of manganese ores. The derived mathematical formulations are applied to estimate the reduction disintegration index (RDI+6.3, RDI+3.15, and RDI−0.5), reduction index (total reduction index (RIT), manganese reduction index (RIM), and iron reduction index (RIF)), and softening-melting property (start of softening (TS1), end of softening (TS2), start of melting (Tm1), and end of melting (Tm2)) of manganese ores. The RDI+6.3 and RDI+3.15 are increased with the individual effect of SiO2 and the interaction effect of iron with silica, while they are decreased as the total iron increased. The high-Fe high-SiO2 manganese ore showed the highest RIT and RIF. The RIM was almost identical in all manganese ores. The presence of high content of SiO2 resulted in a narrow softening range (62–83°C), while the high-Fe high-SiO2 manganese ore exhibited a wider softening range (135–140°C). The melting range was very small in high-Fe low-SiO2 (3–16°C) and high-Fe high-SiO2 (6–8°C) manganese ores, while the low-Fe low-SiO2 manganese ore showed wider melting range (72–74°C). The derived mathematical models are in a good agreement with the experimental results. The calculations are carried out using Matlab program.

Hyperion image analysis and linear spectral unmixing to evaluate the grades of iron ores in parts of Noamundi, Eastern India

This paper reports the results of a study to differentiate iron ores in terms of their grades, using the hyperspectral (EO-1 Hyperion) image data, covering a mineralized belt in the Noamundi area, eastern India. The study involves hyperspectral data collection, pre-processing (reduction of atmospheric and solar flux effects), generation of spectral curves from the image for the iron ore deposits, extraction of key spectral parameters and linear spectral unmixing for mapping iron ore abundance. Spectral curves for iron ore deposits extracted from the Hyperion image pixels exhibit strong absorption at 850–900nm and 2150–2250nm wavelengths, which is typical of iron ores. The strength of the absorption features in the continuum removed spectra varies spatially in the image around the mining areas, indicating differences in composition/grade of the iron ores. Spectral parameters such as the depth, width, area and wavelength position of the absorption features, derived from image spectra in the 850–900nm and 2150–2250nm regions, correlate well with the concentration of iron-oxide and alumina (gangue) in the ore samples obtained from the mine face. Well defined correlations are evident between the concentration of iron oxide and (i) the depth of NIR absorption feature (R2=0.883); (ii) the width of NIR absorption feature (R2=0.912); and (iii) the area of the NIR absorption feature and (R2=0.882). Further, the linear spectral unmixing resulted in an iron ore abundance map which, in conjunction with the image- and laboratory-spectra, helped in assessing the grades of iron ores in the study area. Thus, this study demonstrates the feasibility of discriminating grades of iron ores based on spectral information derived from spaceborne hyperspectral imagery.

A Study on the Potential of Satellite Image-derived Hyperspectral Signatures to Assess the Grades of Iron ore Deposits

Abstract This paper present the results of a study made to assess the grades of iron ore deposits in parts of Noamundi area using the hyperspectral image data (EO-1 Hyperion). The study involves hyperspectral image data, preprocessing (removal of atmospheric effects), spectral curve generation from the image, extraction of certain spectral parameters and spectral data analysis. Atmospheric correction was carried out by using algorithms involving atmospheric analysis of spectral hyper-cubes and Quick Atmospheric Correction modules. Spectral curves generated for the pixels that contain iron ores resemble the spectral signature of iron ores, i.e., very strong absorption at 850-900nm region is observed. The strength of the absorption varies spatially at different pixels. Hence, spectral parameters such as radius of curvature of NIR absorption trough (750-1000nm), position of NIR absorption trough and distance from a reference(100% reflectance) line have been derived for all the image-derived spectra and were compared with the concentration of iron in the ore samples of mines. Empirical models were generated by relating the image-derived spectral parameters of iron ore locations and geochemistry of the samples collected from the same location which shows a reasonable match. Strong negative correlation is seen between the radius of curvature of the NIR absorption trough and concentration of iron with a R2 value of 0.809. The position of the NIR absorption trough is seen to shift towards longer wavelengths with decreasing iron content and the distance from the reference line increases with increasing iron content. Thus, this study indicates that it is feasible to discriminate the grades of iron ores from the spectral parameters derived from Hyperspectral satellite images.

Hyperspectral Radiometry to Quantify the Grades of Iron Ores of Noamundi and Joda Mines, Eastern India

This paper present the results of a preliminary study to assess the potential of the visible, NIR and SWIR energy of the EMR in differentiating iron ores of different grades in a rapid manner using hyperspectral radiometry. Using different iron ore samples from Noamundi and Joda mines, Jharkhand and Orissa, states of India, certain spectro-radiometric measurements and geochemical analysis were carried out and the results have been presented. It was observed that the primary spectral characteristics of these iron ores lie in the 850 to 900 nm and 650–750 nm regions. The spectral parameters for each curve used for studying the iron ores are: (i) the slopes of the spectral curve in 685–725 nm region; (ii) position of the peak with respect to wavelength in 730–750 nm region and (iii) radius of curvature of the absorption trough in the 850–900 nm region. Comparison of these spectral parameters and the geochemistry of the samples indicates that the position of the peak of the curve in 730–750 nm region shifts towards longer wavelength with increasing iron oxide content, while the slope of the curvature in the 685–725 nm region has a strong negative correlation with the iron oxide content of the samples. Similarly, a strong negative correlation is observed between the radius of curvature of the 850–900 nm absorption trough and the iron oxide content. Such strong correlations indicate that hyperspectral radiometry in the visible and NIR regions can give a better estimate and quantification of the grades of iron ores. This study has demonstrated that generation of empirical models using hyperspectral radiometric techniques is helpful to quantify the grade of iron ores with limited geochemical analysis.

Magmatic Ni-Cu-(PGE) deposits in magma plumbing systems: Features, formation and exploration

The three most crucial factors for the formation of large and super-large magmatic sulfide deposits are: (1) a large volume of mantle-derived mafic-ultramafic magmas that participated in the formation of the deposits; (2) fractional crystallization and crustal contamination, particularly the input of sulfur from crustal rocks, resulting in sulfide immiscibility and segregation; and (3) the timing of sulfide concentration in the intrusion. The super-large magmatic Ni-Cu sulfide deposits around the world have been found in small mafic-ultramafic intrusions, except for the Sudbury deposit. Studies in the past decade indicated that the intrusions hosting large and super-large magmatic sulfide deposits occur in magma conduits, such as those in China, including Jinchuan (Gansu), Yangliuping (Sichuan), Kalatongke (Xinjiang), and Hongqiling (Jilin). Magma conduits as open magma systems provide a perfect environment for extensive concentration of immiscible sulfide melts, which have been found to occur along deep regional faults. The origin of many mantle-derived magmas is closely associated with mantle plumes, intracontinental rifts, or post-collisional extension. Although it has been confirmed that sulfide immiscibility results from crustal contamination, grades of sulfide ores are also related to the nature of the parental magmas, the ratio between silicate magma and immiscible sulfide melt, the reaction between the sulfide melts and newly injected silicate magmas, and fractionation of the sulfide melt. The field relationships of the ore-bearing intrusion and the sulfide ore body are controlled by the geological features of the wall rocks. In this paper, we attempt to demonstrate the general characteristics, formation mechanism, tectonic settings, and indicators of magmatic sulfide deposits occurring in magmatic conduits which would provide guidelines for further exploration.

Relevance of geological aspects and ore mineralogy in selecting beneficiation methods for processing of eastern Indian iron ores

Geological aspects, particularly mineralogy and ore genesis of different iron ores have important roles to play in understanding their behaviour during processing and decide suitable beneficiation method for particular type of ore so to produce desired quality end products. The implications of different geological aspects and mineralogical characteristics specific to ore types in mineral beneficiation have been outlined in this paper. Experiments indicated that iron ores, such as massive hard ores, laminated hard ores, fine powdery ore and blue dust ore, do not require complicated processing, however at the other end; sub grade ores, such as flaky, friable, shaly, ochrous, powdery, lateritic and goethitic ores having low iron and high alumina content, require specific beneficiation treatments before their use as direct or as agglomerates in the blast furnace feed. While processing, different ore types need treatment differently for their up gradation. Hence, in addition to the conventional methods of processing such as crushing, screening and washing, advanced beneficiation techniques using concepts of gravity and magnetic separation have found their specific applications for beneficiation of different types of ores, based upon their physicochemical and mineralogical characteristics. Geological setup of the deposits and mode of occurrences of different ore types, physical, chemical and mineralogical characterisation and extensive beneficiation experiments conducted on Indian iron ores have established that quality of lumps can substantially be up graded through simple processing and log washing. On the other hand, for fines ores, Jigging has been found to be the best suitable method. Slime beneficiation requires combination of processes and treatment through hydrocyclones, multigravity separation, magnetic separation and sink float methods, etc. These applications would help not only to recover more values from the inferior grades of iron ores but also to conserve and preserve the natural resources too.

Mode of Occurrence and Characteristics of Mn‐ore Bodies in Iron Ore Group of Rocks, North Orissa, India and Its Significance in Resource Evaluation

Abstract. Several meso‐scale manganese ore bodies, scattered within Jone's horse‐shoe shaped synclinorium, in Bonai‐Keonjhar region of north Orissa are well known in the mineral map of India. Different grades of manganese ores are being exploited from this region by various agencies over a few decades. However, deceptive nature of ore bodies and complexity in control of mineralisation greatly confuse the exploration geologists for evaluation of these resources.In a recent study, the authors have classified Mn‐ore bodies of this region into three broad categories such as stratiform, stratabound (‐replacement) and lateritoid types based on mode of occurrence and their other chemical characteristics. Mn‐ore bands occur in close association with BIF and iron ores. Volcaniclastic shale in large geographic extension encloses these ore bodies.In the stratiform category of ore bodies (BMnF, analogous of BIF), manganese and shale bands, in variables thickness, alternate with each other and extend to a great depth. Such ore bodies generally constitute marginal to low‐grade ores, are characterised by low Mn/Fe ratio (∼2) and have relatively lower abundance of trace (1500 to 2500 ppm) and relatively higher REE constituents. The stratabound‐replacement types of ore bodies are of intra‐stratal nature, occurring within tuffaceous shale. These are mostly shear‐controlled ore bodies extending along a zone of certain width. Increase in average Mn/Fe ratio (∼6) and trace content (5000 to 8500 ppm) by 5 to 2.5 order of magnitude respectively or more above stratiform category are characteristic of these deposits. The lateritoid ore bodies have limited depth persistency. Such deposits are usually very low in Mn/Fe ratio (<1), trace (<2000 ppm) and REE contents.Different methods of exploration techniques are suggested for various categories of Mn‐ore bodies. In this context, the above findings would be the database for the exploration geologists to evaluate the potential of newer/existing Mn‐ore resources in this part of north Orissa.

Using a Combination of Genetic Algorithm and the Grid Search Method to Determine Optimum Cutoff Grades of Multiple Metal Deposits

One of the most difficult problems in mining operation is how to determine optimum cutoff grades of ores at different periods over the lifespan of the mine that will maximize the net present value (NPV) of the mine. Maximizing the NPV of a mining operation, subject to different constraints is a non-linear programming problem. These problems can often be solved by the use of gradient methods, direct search methods or intelligent optimization methods. In this paper, a hybrid genetic algorithm combined with the grid search method is used to find the optimum cutoff grades of multiple metal deposits that will maximize the NPV. At first, the solution space is determined by using the grid search method, then the optimum cutoff grades are determined accurately by the use of genetic algorithm. The result of a sensitivity analysis of the problem shows that when crossover probability ranges between 55 to 70%, and mutation probability is between 8 to 11%, and population size greater than 35 individuals; the optimum cutoff grades can be determined with high accuracy while keeping the computational time relatively low.

Beneficiation of west sibaiya phosphate ores by flotation in alkaline media

Four big head phosphate samples (about 200 kg) were collected from West Sibaiya mines [medium grade (sample 1, southern mine), high grade (sample 2, the mine in the cultivated area), low grade (sample 3, oversize), and tailings (sample 4) phosphate ores]. The representative samples were analyzed chemically for P2O5, Fe2O3, Al2O3, InR, CaO, MgO, TiO, MnO, SO 4 2− , F−, Cl− loss on ignition (LOI), and U before and after screen analysis (−10.0 +9.50, −9.50 +6.70, −6.70 +2.0, −2.0 +1.0, −1.0 +0.85, 0.85 +0.710, −0.710 +0.500, −0.500 +0.350, −0.350 +0.250, −0.250 + 0.180, −0.180 +0.125, −0.125 +0.075, and −0.075-mm-size fractions). The different grades of phosphate ores (organogenic-granular phosphorite ores with carbonates, calcite, calcedony, etc.) were beneficiated using local crude rice bran oil and imported oleic acid (individuals) as collectors, NaOH or KOH as the pH adjustor, and Na2SiO3 as the silica depressant. The results indicate that −0.355, +0.180 mm grain size, pH=9.6, 20 minutes conditioning time, 0.7 kg Na2SiO3 (depressant)dose/ton feed ore, 4.25 kg rice bran oil dose/ton feed of phosphate ore or 3.4 kg oleic acid (collector) dose/ton feed of phosphate ore, and cleaning (reflotation) of phosphate concentrates are the optimum conditions for beneficiation of Sibaiya phosphate ores. On cleaning (reflotation) the phosphate ore feeds of samples 1 (medium, P2O5=28.67 pct), 2 (high, P2O5=31.70 pct), 3 (oversize, P2O5=25.30 pct), and 4 (tailings, P2O5=22.61 pct)using rice bran oil as a collector, the feeds beneficiate into concentrates of P2O5 pct equal to 31.87, 34.70, 26.16, and 31.90 pct (recoveries equal 49.41, 61.41, 52.01, and 29.03 pct P2O5) for samples 1, 2, 3, and 4, respectively. On using oleic acid as a collector, P2O5 pct in phosphate feeds of samples 1, 2, 3, and 4 increases (upgrades) into 31.28, 33.95, 26.82, and 30.70 pct in concentrates (recoveries equal 61.74, 53.60, 53.31, and 36.30 P2O5). Comparing the results obtained on using rice bran oil and oleic acid as collectors from the economic point of view, the costs of producing 1 ton phosphate concentrate by rice bran oil are lower (∼LE 70) than those on using oleic acid (∼LE 100) as a flotation collector.

Virgin versus mature reserves: A dilemma for new investment

Abstract During the mining cycle the general rule is to observe declining grades of ores and minerals being exploited along the life of most mines. This is more evident for metal mines than for industrial minerals. One important consequence is the increasing operating cost, aggravated by the not negligible environmental compliance costs appearing in the last decades. Two examples are depicted here: copper and kaolin (high grade type) reserves. It is argued that mining of virgin reserves is presently a competitive advantage in favor of developing countries.

New Bentonite Extension Test Provides A Better Gel Quality Evaluation

Abstract A bentonite extension (BEXT) lest has been developed as a bentonite quality control procedure. Unlike the API bentonite quality control test, the HEXT test will differentiate between poorer and better grades of bentonitic ores. The BEXT lest generates an ultimate yield point for a bentonite based upon that bentonite's maximum extendability in fresh water. Beneficiating polymers commercially added to bentonite samples do not affect ultimate yield point values. Bentonite samples with ultimate yield paints greater than 30 pascals are shown to produce fresh water bentonite muds with acceptable rheological properties. Poorer quality bentonites having ultimate yield points of less than 16 pascals do not give adequate yield points or gel values. Data presented from the BEXT test correlates closely to western Canadian drilling performance. Field data demonstrate that faster drilling rates and fewer hole problems have been realized when good quality bentonites, as specified by the BEXT test, have been used. A review of case histories for foothills wells indicates better hole cleaning and improved suspension properties have been observed when poorer quality bentonites were replaced by better quality gels. Drilling costs have been significantly reduced when better quality bentonites are used for fresh water drilling operations. Introduction Improved hole cleaning and suspension characteristics or drilling fluids have commonly been associated with reduced drilling problems. This is especially true when fresh water systems normally associated with significant hole washouts are used. Most of Shell Canada's rheological problems in recent years have been associated with poor quality bentonite. Therefore, a quality control program was initiated ror bentonitic clays to reduce drilling problems and mud costs in the field. This paper discusses testing procedures as well as field results for fresh water drilling fluids. Gel/XC polymer costs have been reduced by at least 37% in areas where the program has been implemented. Bentonite Quality Most bentonitic days used in the drilling industry have beneficiating agents added during milling operations. .Although the agents have qualified interior clays to API specifications, problems meeting our rheological specifications in the field have been observed where poor quality bentonite has been used(1). With additions of poor quality bentonite minimal increases in yield point and initial gels have been observed, while methylene blue test values, plastic viscosity, gel progression and % sounds increase significantly making the drilling fluid more susceptible to contamination as well as more costly. In contrast, with higher quality bentonite additions both yield point and initial gel values improve significantly. The current approved use of extending polymers to upgrade bentonite has led to concern about true bentonite quality(2). A new method to ensure bentonite quality is required to replace the current API procedure. Alternate quality procedures for bentonite have been proposed, however, none of these methods quantitatively measure raw bentonite quality(3,4). Bentonite Extension Text (BEXT Test) The BEXT test was developed to quantitatively measure bentonite quality. This procedure measures the maximum yield potential of bentonite samples for a standard bentonite extender Alcomer 1773.

Determination of chromium in chrome ores

A method for the estimation of chromium in chrome ores is reported. Manganese dioxide or manganese ore in the presence of 9 M sulphuric acid is used for the oxidative decomposition of different grades of chrome ores. The results compare favourably with those obtained by standard methods.

Microbial mutualism in leaching of Cu−Ni sulfide concentrate

With tightening legislations on air pollution and decreasing grades of Cu and Ni ores, the mineral processing industry will have to find an alternative to smelting. One such hydrometallurgical alternative is bacterial leaching; it utilizes the action of Thiobacillus ferrooxidans on sulfide minerals converting them to metal sulfates which can be leached by acid produced by the bacteria. The metal is recovered by cementation, solvent extraction or electrowinning. In the present paper, the authors report their test work with a Cu-Ni sulfide concentrate and show that the mutualistic association of T. ferrooxidans with nitrogen-fixing bacteria Beijerinckia lacticogenes helps leach more metal faster in a leaching medium devoid of any added carbon or nitrogen source. Use of intentionally mixed bacterial culture in ore leaching has not been previously reported.

A PORTABLE GAMMA RAY LOGGER AND THE ESTIMATION OF GRADE AND ORE RESERVES IN RADIOACTIVE DEPOSITS WITH REFERENCES TO LOGGING AT OUCHI DISTRICT MIYAGI PREFECTURE

Variations of the distribution of the gamma ray intensity in drill holes, with the length of the detector, thickness of radioactive beds and diameter of the holes, are discussed. A portable gamma ray logger, with a special scintillation detector having a diameter of only 30 millimeters, was constructed for the purpose of prospecting in mountain regions. A method of estimating the thickness of the horizontal ore beds and the grades of ores was obtained from a theoretical calculation, utilizing a constant determined by experiments in drill holes. Moreover, the area between the counting rate curve and the base line on a radioactivity log is proportional to the product of grade and thickness, independent of drill-hole diameter and logging speed. Therefore, the ore reserves may be estimated rather easily, and the mean grade is calculated when a proper value for thickness is given. Using this portable radioactivity logger, radioactivity in the Ouchi district of Miyagi prefecture was measured. A slight anomaly w...

原子燃料公社ウラン鉱山開発業務の現況

The Atomic Fuel Corporation has been paying a great effort for the development of uranium mines in this country since its establishment in 1956. The prospecting has so far been centered on the uranium deposits stretching, round Ningyo-toge Mine. The underground prospecting investigating on the feasibility of industrialization of the mine has been done with similar method of ordinary metal mines. Moreover, suitable drifting method has been carried out in conjunction with the progress of prospecting on sedimentary uranium deposits. Although there were many difficulties for the ore reserve calculations because of the wide varieties of the seam thickness and the grades of ores, a suitable method has been applied to the calculation as a result of research. At present, the stoping method is in the testing stage as the type of the deposit is different from those in other parts of this country and in the world. As preliminary testing, two stoping methods, namely the pillar method and the long wall method using the iron props and caps of the ordinary coal mines have been tested and brought about a success. Aiming at the raising of the efficiency, excavation and face conveying method have been put under testing. For the safety of the mine, an attention was given to the special nature of the mine as a nuclear source material producting mine and a special policy has been applied in addition to those of the ordinary metal mines.

Prudent Utilization of the Chromite Reserves in India

The chromite ore occuring in India at various places is not of the same composition and this has led to its grading as low, medium and high. Recently, the Government of India has decided to allow an export of a quantity of 15,000 tons of chrome, ore for the first half of 1954. As chromite ore has a very strategic importance for a country wishing to develop its resources, it will be proper to assess its reserves in the country and then devise methods for its proper utilisation. Reserves of high grade chromite cre. are of the order of 300,000 tons and the reserves of the low grade chromite ore are also of the order of 300,000 tons. The expected developments of some more steel plants in the country, the production of different types of alloy steels in future and the manufacture of different chemicals, from the chromite ore, required for the textiles, tanning ond other industries, etc., are to be taken into consideration in devising ways and means of utilising the different grades of ores in the best possible manner and also to conserve sufficient stocks for future use. It should also be seen whether it would be proper for India to export this strategic ore in future.