scholarly journals Comminution Effects on Mineral-Grade Distribution: The Case of an MVT Lead-Zinc Ore Deposit

Minerals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 893
Author(s):  
Gabriele Baldassarre ◽  
Oliviero Baietto ◽  
Paola Marini
Keyword(s):  
Grain Size ◽  
Texture Features ◽  
Mining Operation ◽  
Mississippi Valley ◽  
Grade Distribution ◽  
Lead Zinc ◽  
Energy Consuming ◽  
Definition Of ◽  
Crushing Behavior ◽  
Size Threshold

Every mining operation is followed by a beneficiation process aimed at delivering quality materials to the transformation industry. Mainly, in order to separate valuable minerals from gangue in mineral processing, the crushing and grinding of extracted ore are crucial operations for the following separation steps. Comminution is the most energy-consuming operation in mining, and the quality of the results is strictly related to the characteristic of the material under treatment, the type of equipment used in comminution, and the circuit design adopted. A preliminary study was performed in order to understand the crushing behavior under different comminution forces of a high-grade mixed Zn-Pb sulfide ore sample, collected in a Mississippi-Valley Type (MVT) deposit, and the distribution of the target minerals among the products of the process. Ore samples were examined and characterized through thin section observation and SEM analyses for the determination of grain size and texture features, while X-ray powder diffraction (XRPD) quantitative analyses were performed for the definition of target mineral concentrations of comminuted product samples. The selected crushing and grinding circuit comprised lab-scale equipment. For each stage of the process, products below the estimated free-grain size threshold were collected, and particle size analyses were carried out. Comminution products were divided into size distribution classes suitable for further separation operations, and XRPD analyses showed a mineral-grade distribution varying with the dimensions of the products. Characterization of the ore material after crushing and grinding force applications in terms of the distribution of target minerals among different-sized classes was achieved. The important trends highlighted should be considered for further investigation related to an efficient separation.

Comminution effects on mineral grade distribution

2020 ◽  
Author(s):  
Gabriele Baldassarre ◽  
Oliviero Baietto
Keyword(s):  
Grain Size ◽  
Froth Flotation ◽  
Mining Operations ◽  
Thin Sections ◽  
Grade Distribution ◽  
Important Trend ◽  
Disk Mill ◽  
Definition Of ◽  
Quality Material ◽  
Size Threshold

<p>Every mining operations is followed by a beneficiation process aimed to deliver quality material to the transformation industry. Mainly, in mineral processing comminution and grinding of extracted ore, are crucial operations for the following separation steps in order to obtain valuable minerals from gangue.</p><p>Comminution is the most energy consuming phase and the quality of the results is strictly related to the characteristic of the material under treatment.</p><p>A preliminary study has been performed in order to understand the crushing behaviour of a mixed sulphide ore, containing galena and sphalerite, and the distribution of the two target minerals among the different sized products of the process.</p><p>Ore samples have been examined and characterized by means of thin sections observation and SEM analyses for the determination of the free grain size, while XRD quantitative analyses have been performed for the definition of the grades.</p><p>The selected crushing circuit comprises lab-scale impact crusher, jaw crusher, disk mill and rod mill. For each stage of the process products below the free grain size threshold have been collected and particle size analyses have been carried out.</p><p>Comminution products were divided in dimensional classes suitable for flotation separation, ranging between 0.250 and 0.075mm and XRD analyses showed a variable mineral grade distribution varying with the reduction in dimension of the products.</p><p>This important trend should be considered for further investigation related to an efficient froth flotation separation.</p>

Production data for the upper Mississippi Valley lead-zinc district

1959 ◽  
Author(s):  
A.V. Heyl ◽  
A.F. Agnew ◽  
E.J. Lyons ◽  
C.H. Behre
Keyword(s):  
Production Data ◽  
Mississippi Valley ◽  
Lead Zinc

scholarly journals Multi-scale characterizations of colon polyps via computed tomographic colonography

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Weiguo Cao ◽  
Marc J. Pomeroy ◽  
Yongfeng Gao ◽  
Matthew A. Barish ◽  
Almas F. Abbasi ◽  
...  
Keyword(s):  
Area Under The Curve ◽  
Texture Features ◽  
Learning Model ◽  
Colon Polyps ◽  
Texture Descriptor ◽  
Operating Characteristics ◽  
Computed Tomographic ◽  
Multi Scale ◽  
Definition Of ◽  
Occurrence Matrix

AbstractTexture features have played an essential role in the field of medical imaging for computer-aided diagnosis. The gray-level co-occurrence matrix (GLCM)-based texture descriptor has emerged to become one of the most successful feature sets for these applications. This study aims to increase the potential of these features by introducing multi-scale analysis into the construction of GLCM texture descriptor. In this study, we first introduce a new parameter - stride, to explore the definition of GLCM. Then we propose three multi-scaling GLCM models according to its three parameters, (1) learning model by multiple displacements, (2) learning model by multiple strides (LMS), and (3) learning model by multiple angles. These models increase the texture information by introducing more texture patterns and mitigate direction sparsity and dense sampling problems presented in the traditional Haralick model. To further analyze the three parameters, we test the three models by performing classification on a dataset of 63 large polyp masses obtained from computed tomography colonoscopy consisting of 32 adenocarcinomas and 31 benign adenomas. Finally, the proposed methods are compared to several typical GLCM-texture descriptors and one deep learning model. LMS obtains the highest performance and enhances the prediction power to 0.9450 with standard deviation 0.0285 by area under the curve of receiver operating characteristics score which is a significant improvement.

The distribution of lead, zinc, and chromium in fractions of bottom sediments in the Narew River and its tributaries

2008 ◽  
Vol 37 (4) ◽  
Author(s):  
Mirosław Skorbiłowicz ◽  
Elżbieta Skorbiłowicz
Keyword(s):  
Heavy Metals ◽  
Grain Size ◽  
Bottom Sediment ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Bottom Sediments ◽  
Catchment Area ◽  
Sediment Pollution ◽  
Lead Zinc

The distribution of lead, zinc, and chromium in fractions of bottom sediments in the Narew River and its tributariesThe purpose of the paper was to evaluate the distribution of lead, zinc and chromium contents in different grain fractions of bottom sediments in the Narew River and some of its tributaries. This study also aimed to determine which fractions are mostly responsible for bottom sediment pollution. The studies of the Narew and its tributaries (the Supraśl, Narewka, and Orlanka) were conducted in September 2005 in the upper Narew catchment area. The analyzed bottom sediments differed regarding grain size distribution. The studies revealed the influence of the percentage of particular grain fractions present on the accumulation of heavy metals in all bottom sediments.

Mississippi Valley-type lead–zinc deposits through geological time: implications from recent age-dating research

2001 ◽  
Vol 36 (8) ◽  
pp. 711-740 ◽  
Author(s):  
David L. Leach ◽  
Dwight Bradley ◽  
Michael T. Lewchuk ◽  
David T. Symons ◽  
Ghislain de Marsily ◽  
...  
Keyword(s):  
Age Dating ◽  
Mississippi Valley ◽  
Geological Time ◽  
Lead Zinc ◽  
Mississippi Valley Type ◽  
Valley Type ◽  
Zinc Deposits

scholarly journals A Proposed Revision to the Definition of “Derecho”

2016 ◽  
Vol 97 (6) ◽  
pp. 935-949 ◽  
Author(s):  
Stephen F. Corfidi ◽  
Michael C. Coniglio ◽  
Ariel E. Cohen ◽  
Corey M. Mead
Keyword(s):  
Initial Step ◽  
The United States ◽  
Early Years ◽  
Mississippi Valley ◽  
Physical Processes ◽  
Convective Systems ◽  
Convective Structures ◽  
Physically Based ◽  
Wind Events ◽  
Definition Of

Abstract The word “derecho” was first used by Gustavus Hinrichs in 1888 to distinguish the widespread damaging windstorms that occurred on occasion over the mid–Mississippi Valley region of the United States from damaging winds associated with tornadoes. The term soon fell into disuse, however, and did not appear in the literature until Robert Johns and William Hirt resurrected it in the mid-1980s. While the present definition of derecho served well during the early years of the term’s reintroduction to the meteorological community, it has several shortcomings. These have become more apparent in recent years as various studies shed light on the physical processes responsible for the production of widespread damaging winds. In particular, the current definition’s emphasis on the coverage of storm reports at the expense of identifying the convective structures and physical processes deemed responsible for the reports has led to the term being applied to wind events beyond those for which it originally was intended. The revised definition of a derecho proposed herein is intended to focus more specifically on those types of windstorms that are the most damaging and potentially life threatening because of their intensity, sustenance, and degree of organization. The proposal is not intended to be final or all encompassing, but rather an initial step toward ultimately realizing a more complete physically based taxonomy that also addresses other forms of damaging-wind-producing convective systems.

Pétrographie et altération de la matière organiquedu gisement de plomb–zinc–cuivre de tourist–Bou Beker,Maroc nord oriental

1996 ◽  
Vol 33 (10) ◽  
pp. 1363-1374 ◽  
Author(s):  
M. Bouadellah ◽  
A. C. Brown ◽  
Y. Héroux
Keyword(s):  
Organic Matter ◽  
Ore Deposits ◽  
Mississippi Valley ◽  
Sulfide Mineralization ◽  
Mineralization Process ◽  
Associated Gas ◽  
Regional Flow ◽  
Lead Zinc ◽  
Reflectance Measurements ◽  
Ore Deposition

Reflectance measurements and organic petrography were used to study altered organic matter in the dolomitic Middle Jurassic Beddiane sequence hosting the Beddiane lead–zinc deposit. Organic matter occurs in the lower dolostone units of the formation where zinc sulfide mineralization prevails. The upper units, where lead sulfide mineralization is dominant, contain lesser amounts of organic matter. The organic matter in the Beddiane sequence consists of macerals, amorphous kerogen, and solid bitumen, inertinite and vitrinite are ubiquitous. The amount of exinite increases toward mineralized areas but the ratio exinite/kerogen remains constant. Two types of vitrinite are considered on the basis of their reflectance: Vt1 with low reflectance values (0.3–0.5%) and Vt2 with higher values (0.7–1.25%). The ratio Vt1/Vt2 increases and the reflectance values for Vt1 decrease toward the zinc-prevailing units, Organic matter associated with the mineralization exhibits features such as oxidation halos and desiccation cracks, together with a low-fluorescent exinite. The association of the kerogen content, the trend in reflectance values, and the alteration features of the Mississippi Valley-type Beddiane deposit support the hypothesis that the regional flow of hot brines associated with the mineralization process was the cause of anomalous heating, that the occurrence of exinite maceral and its associated gas played a role in the ore deposition, and that the new chemical equilibrium reached by the zinc-dominant host rock after ore deposition is responsible for the suppressed reflectance values within and near the ore deposits.

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