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By Z. Abdel-Khalek, Hassan El-Shall, S. Farrah, C. Boice

Selective adsorption and surface modification of minerals by surfactants is the primary step in the process of separating certain minerals with similar physical and chemical characteristics in the flotation process. In this study, microorgan- isms are used as surface modifiers for francolite and dolomite. Results of adsorption experiments with francolite and dolomite show that the microbes selectively adsorb to one of the minerals under specific operating conditions. In preliminary flotation experiments, it is found that the microorganisms enhance or depress flotation of the minerals leading to an increase in the efficiency of separation between the francolite and dolomite. The conditions leading to selective adsorption (surface modification) and subsequently to possible efficient separation of these two minerals are discussed in this paper.

Jan 1, 2002

By A. Halim, A. Martikainen, S. GYAMFI

This paper outlines a unique case of the development of strategies to reduce ventilation and heating costs in Konsuln iron ore mine in northern Sweden. The mine, located just south of Luossavaara-Kiirunavaara Aktiebolag’s Kiruna iron ore mine, was developed as a test mine from 2018-2020 for the Sustainable Underground Mining (SUM) project. Besides functioning as a test mine, Konsuln also contributes to ore production. The existing mine ventilation system was designed for the current production rate of 0.8 million tons per annum (Mtpa). There is a plan to increase this rate to between 1.8 and 2.0 Mtpa.

Dec 23, 2021

By Xintan Chang

A computer software package, named CFIRE, for the general ventilation network analysis and fire control, mine fire and/or coal spontaneous combustion, has been developed at Xian Mining Institute in China. It is a multipurpose package with adequate capacities of ventilation map drawing, ventilation network analysis, gob fire simulation, steady state ventilation simulation and transient state ventilation simulation. It was written in a user-friendly style, driven by menus, facilitated by on-screen messages and supported by the allowance of user interferences. CFIRE has used up-to-date research findings focussing on the practical needs of coal mines. This paper discusses briefly also the relevant theoretical principles on which this package has been perceived.

Jan 1, 1989

By G. W. Luxbacher

Coal mine infrastructure is rarely designed solely on the basis of ventilating the underground workings. Instead the optimization of a mining sequence, the minimization of coal quality variation, reduction of coal losses by adapting to property boundaries and geologic structure (seam inclination, roof conditions, coal thickness, etc.) or other similar considerations have formed the objective for mine plant design and layout. Infrastructure development may also reflect a desire to maximize production early in the life of the mine or to permit flexibility in mining according to market conditions. Requirements for coal mine ventilation, established by the 1969 Coal Mine Health and Safety Act, have mandated changes in the traditional concepts of mine plant design in the United States. Mines, in operation prior to the passage of the Act have experienced severe limitations when attempting to adapt the existing mine infrastructure to meet the requirements of the law. In addition the increased quantities of air required, velocity limitations on trolley haulage and belt lines, the establishment of separate intake escapeways and gob area ventilation have com- pounded the inherent complexity in planning mine ventilation systems. Past practices in mine ventilation planning and design are no longer adequate. Given the complexity of today's ventilation systems, effective planning and design approaches are required. As such, the interrelationship between the overall coal mine plant design and ventilation system design is examined. An approach to ventilation system design constrained by global considerations of mine plant design, is presented. The proposed approach is, however, applicable to the design of new mine ventilation systems as well as to the modification of existing systems.

Jan 1, 1980

By Kuda R. Mutama, Allen E. Hall

A wind tunnel investigation into the fundamental characteristics of jet fan performance is described. The effects of varying fan positioning in a square tunnel cross section are reported for two fan outlet diameters and velocities. Tests were conducted, also for a jet fan placed in a flow developed by an external fan operating in the same direction as the jet fan. The position of the jet fan relative to the tunnel walls was found to affect its performance. Performance parameters were determined and used to formulate theoretical equations based on momentum and energy considerations. The results identified a range of flow ratios which can be used to design an effective jet fan ventilation system and provide a basis for the selection of jet fans for practical mining applications

Jan 1, 1997

By Saurabh Rastogi, Vikram Shishodia, B. Pitchumani

Comminution is a unit operation which consumes major part of energy in mineral processing industries such as fertilizer production. Ball mills are widely used for size reduction of a given ore to the liberation size that is required in further beneficiation processes. In grinding of materials much effort is concentrated on control of top size of the product and this results in production of fines, also creates secondary problems of pollution due to the difficulty in the collection of fine particles. The present work has been carried out to control product size distribution for rock phosphate grinding in an Industrial Ball Mill of 600 TPD. The plant data are taken for a given feed distribution and mill operating conditions. The information at various Ball Size distributions are collected. The comminution functions such as specific rate of breakage and breakage distribution functions are estimated by back calculation technique to solve the mass balance equation. A simulation program is written to study the product size distribution obtained for various ball size distribution.

Jan 1, 1993

By B. Andersen, P. Somasundaran

An accurate knowledge of the interactions among mineral particles and between such particles and dissolved and precipitated species is important in developing efficient separation processes. In this investigation, interactions relevant to dispersion and selective reagent adsorption (the two main prerequisites for selective flocculation) within Florida phosphatic clay Waste were studied. Initial studies with artificial slimes, consisting of pure clay and phosphate minerals, showed dispersion of artificial slimes to be relatively easy. The problems that were encountered during selective flocculation of the artificial slimes were due to unselective polyacrylic acid adsorption on clay, which was caused by the presence of multivalent calcium ions on the exchangeable cation positions on the clay surfaces. This problem could be solved by exchanging calcium for sodium, which reduces the interaction between the polymer and the clay surface. This procedure, however, was not successful for mineral mixtures. Natural slimes were found to be much more difficult to disperse. This was attributed to the presence of cementing materials such as humic substances and Al and Fe (hydr)oxide precipitates. Selective removal of these cementing materials resulted in good dispersion and partial separation. A further increase in the separation of natural slimes is most likely determined by the presence of calcium on the clay surfaces, as was found for the artificial mixtures.

Jan 1, 1994

The deformation, failure, and filling characteristics of a caving roof in the initial and normal mining stages of a pitching oblique longwall mining area are analyzed using large-scale threedimensional physical-similitude experiments and numerical calculations to study the characteristics of roof fracture and migration in a steeply dipping seam. The results show that the roof fracture development has evident sequential and spatial characteristics. Among them, immediate roof breaking in different parts of the mining area shows difference in time and space. The failure sequence of the immediate roof in different areas changes with the mining; unique regional stability evolution characteristics are observed in the suspended immediate roof simultaneously, resulting in its significant regional stability on the goaf filling.

Jan 7, 2020

By Charles E. Weaver

A core from the La Camelia attapulgite mine in north Florida was studied in detail to determine the detailed vertical variability and the relations of the various parameters. The structural, textural, mineralogical and chemical data indicate there are two major depositional cycles represented within the minable interval. The sediments deposited during the two cycle differ in detail but in general are similar. The environments of deposition grade from shallow marine to lagoonal to tidal flat to marsh. The sedimentary structure (lamination, burrows, pebble conglomerate), mineralogy (attapulgite, montmorillonite, sepiolite, dolomite, calcite) chemistry (Al, Mg, Fe) are closely related to each other and their nature is determined by the depositional environments. Most of the clay minerals and carbonate minerals are authigenic and are therefore particularly sensitive to environmental differences. The variability and environmental features seen in this core are characteristic of the sediments in the general attapulgite mining area. A detailed understanding of the relationships discussed should be of value in prospecting, mining and processing.

Jan 1, 1972

By Lucien Duckstein

The purpose of this paper is to give recommendations for utilization of water resources in a mining region, considering also water supply and environment; the case study of mining for coal and bauxite under the karstic aquifer of the Transdanubian mountain of Hungary is used to illustrate the approach, which consists in formulating a static multiobjective control model and solving it by compromise programming. The three activities of regional mineral resource exploitation, water supply and environmental protection are represented by different objectives which cannot be expressed in commensuerable units. Thus, a solution which is optimal for one objective is usually far from being optimal with respect to the other two objectives. As a result, we are not seeking an optimal solution for the conjunctive regional system, but a good compromise, trade-off or "satisfactum" (1), (2).

Jan 1, 1979

By A. M. Johnson, M. A. Cornachione

The west central Upper Peninsula of Michigan contains a large resource of graphitic slate. The slate has potential industrial use as a substitute for shale currently used in the production of portland cement. Some of the unweathered slate, however, has a high concentration of pyritic sulfur that can create emission problems when processed in a kiln. A low-cost method to reduce the sulfur content of the slate through the optimization of pyrite oxidation in a bio-heap leaching operation was investigated. In this study, optimal conditions for the bacterium Thiobacillus ferrooxidans were created to promote pyrite oxidation and, therefore, sulfur removal from the slate. Preliminary lab scale flask tests using crushed and sized slate (-40 + 100 mesh) and T. ferrooxidans bacteria in a sulfuric acid medium resulted in 70% oxidation of pyrite over a one-month period. Subsequent column leaching tests on coarser materials (-3/8+1/4 in.) operated for six months resulted in a maximum reduction of total sum of 75%. These data suggest that bio-heap leaching to remove sulfur from the slate for use as a kiln feed material is viable.

Jan 1, 1995

The exploitation of mineral deposits for economical recovery of the contained minerals has many aspects differing from other industrial or manufacturing operations. However, generally accepted principles of good organization and management applicable to industrial plants are similarly effective for mineral processing plants. A more detailed coverage of organizational structures and management techniques than is possible in this section can be obtained from many good books devoted wholly to these subjects. A few of the more readily available examples are included in the general references at the beginning of this section. The field of mineral processing encompass a wide variety of minerals, processes, flowsheets, equipment, and end products. Mineral deposits, mines, and related beneficiation plants are found in all parts of the globe, often in remote locations with no nearby support for supplies and maintenance. Available labor is frequently unskilled, sometimes primitive, and often untrained without machine and hand tools or heavy equipment experience. Such situations call for well- planned and conducted training programs covering the full range of mining-type job skills. Climates can range from arctic to tropical and from arid to extremes of rain or snow, and the mine and plant sites can be almost anywhere. However, it is often possible and sometimes necessary for

Jan 1, 1985

By G. Rinelli, Paul R. Jr. Smith

Preparation for flotation begins with dragline mining, pumping, washing, screening, and desliming. Slimes, nominally -150 mesh material, constitute large quantities of phosphate and water which are a disposal problem. Older techniques involve sizing at about 35 mesh for separate coarse and fine treatment. The plus 14 mesh fraction does not require concentration. Coarse treatment includes agglomerate spiralling, belt flotation, thickening, scrubbing with sulfuric acid, de-oiling for reagent removal, and cationic flotation of fine quartz. A recent trend is to screen at coarser than 35 mesh size and eliminate coarse particle treatment, sacrificing some grade of this product. Techniques for flotation concentration of the fine size fraction are discussed.

Jan 1, 1976

By Patti J. Best

The Southern Powder River Basin (SPRB) now commands 30% of the US utility, coal market due to the region's low mine production costs, competitive rail rates and low sulfur content. In 1997, production exceeded 240 Mt (265 million st). This was an in¬crease of 104 Mt (115 million st) since 1989 and 4.5 Mt (5 million st) above 1996. Continued growth is expected as the second phase of the Clean Air Act Amendments (CAAA) approaches. This growth will be the greatest in the southern part of the Basin where coal quality is higher. Coal characteristics SPRB coal is classified as subbituminous due to its low heating value and high moisture content. The coal is characterized by low sulfur and ash contents, low ash fusion temperatures and high reactivities. In 1997, the average heating content was 8,593 Btu/lb, with an average sulfur and ash content of 0.79 lbs S02/million [ ] Btu and 5.13%, respectively. The distinguishing characteristic of SPRB coal is its low sulfur content. Most SPRB coal contains less than 1.2 lbs S02/million Btu. This is the approximate definition of "compliance" coal for Phase II of the CA AA. Much of the coal, particularly in the southern part of the Basin, is referred to as "super-compliance" coal due to SO2 contents of between 0.4 and 0.7 lbs SO2/million Btu. The SPRB is divided into three geographic clusters based on coal quality. Mines located in the southern part produce coal with the lowest average sulfur content and highest heating content, almost 400

Jan 1, 1998

By Stephen P. Harrison

The ventilation of coal mines has long been a major challenge for the mining industry. Prior to the 1969 Health and Safety Act, mine ventilation planning was almost entirely handled by individuals in mine operations and engineering who had extensive practical experience. Their background and expertise was sufficient to deal with existing ventilation problems and planning. A recent decline in the number of qualified individuals combined with more stringent state and federal regulations have necessitated a thorough engineering oriented approach to ventilation in mine planning design. To plan for an existing mine, a thorough ventilation survey must be conducted to determine the capabilities of the existing ventilation network. A ventilation survey also provides considerable useful data for long range planning. Essential information such as friction factors, entry resistance, and potential ventilation problem areas is gained from the survey data. With this information a comprehensive computer analysis can be conducted to evaluate alternative mine plans. This evaluation of mine plans is essential to minimize the number of shafts required while still maintaining the quality of mine ventilation. Using an existing mine as an example, this paper outlines a detailed procedure for organizing, con-ducting, and evaluating a ventilation survey. In addition, specific ventilation problem areas are isolated and alternative methods for their solution are considered. Furthermore, a long range mine plan is evaluated and the most feasible variation of the plan is selected.

Jan 1, 1980

By B. Mishra, A. Staley, D. Kirkpatrick

The major waste product of the alkaline extraction of alumina from bauxite (Bayer Process) is known as red mud. Approximately one ton of red mud is produced for every two tons of bauxite mined. The red mud produced from Jamaican bauxite is rich in hematite, alumina and titanium oxide. It has been shown that more than 90% (by weight) alumina can be recovered from red mud by soda ash sintering and caustic leaching. Hematite can be carbothermically reduced with a degree of metallization of more than 94%, resulting in attempts, for magnetic separation. These separations are desirable because there are no waste products generated. Consequently, there is an opportunity for complete utilization of the waste material. Conversely, the preseparated material could be charged through the tuyeres in an iron blast furnace, or it could be smelted to produce pig iron. If smelted, the concentration of titanium oxide in the slag would be high enough to justify its recovery by an established acid-leach process. This paper describes the results of alumina recovery and the plans for titanium oxide recovery from red-mud. In addition, the situation of ongoing efforts in iron extraction, particularly, the method of magnetic separation of the reduced material. The problems associated with the use of reduced red mud as an alternative to direct-reduced iron (DRI) is also discussed. A critical assessment of the recovery sequence chosen for the products is described based on economics. Key words: Red mud, Waste product utilization, Alumina recovery, Titanium oxide, Iron

Jan 1, 2003

By D. D. Misra

Though computer simulation of coal beneficiation has been in use for nearly two decades the models used in the programs for the simulation of the crushing processes concentrate mainly on the size distribution. This paper suggests the use of an empirical equation approximating to the cumulative probability or error function for the simulation of the liberation process in coal crushing. The algorithm outlined here can be incorporated in a computer program already having a size distribution model.

Jan 1, 1989

By M. G. Ayat, B. C. Scott

H. P. Ferri I refer to the article "Degradation Process in Coal Slurry Pipelines" by M.G. Ayat and B.C. Scott in the September 1988 issue of Mining Engineering. I would like to congratulate Dr. Ayat and his colleague on a very interesting and valuable piece of work. This article is an excellent one, describing a real phenomenon that has been ignored for so long. I do, however, have an objection. The article fails to address the degradation process when coal is processed or transported in other ways than slurry form, particularly those employed in this work. Could, for example, screening (wet or dry) have contributed to the extent of degradation? Perhaps scanning electron micrographs of the samples examined and after screening would have helped to clarify this. I would like to point out that degradation is also observed in pneumatic conveying systems, mechanical conveying, and other means of transportations employed by the mineral industry. Reply by M. G. Ayat We gratefully acknowledge Dr. Fern's comments on the subject paper. As he so rightly points out, the degradation process is a real problem, not only in coal slurry pipelines, but also in many handling and processing equipment employed by the coal and mineral industry. Scanning Electron Microscopic examination of samples may offer very little information about the extent of degradation for several reasons. One is that preparing a representative sample that has undergone degradation will be extremely difficult if not impossible. This problem is exacerbated by the fact that SEM requires only very small amounts of material for testing. Secondly, there is a sample preparation step involved in the SEM examination and, as such, it would be very difficult to associate the extent of degradation to either sample preparation or handling and processing operations. Finally, it is probably worth mentioning that degradation is a multi-faceted phenomenon involving many natural and man-made factors. The logical approach to this problem would, therefore, seem to be a "one-step-at-a-time" approach.

Jan 2, 1989

By D. Jacobson

There are many different machine design parameters and variables that affect the production of cone crushers in a mineral processing plant. One of these variables is the speed at which the cone gyrates. In June 2012, pilot tests were conducted to determine the production and operating conditions over a wide spectrum of speeds. mining operations will have variations in the ore characteristics and feed rates that result in non optimal use of the crushing energy and inconsistent process control. This study documents the measured variation in production and energy efficiency with two operating modes. Overall, the results match the theory, and the capacity and power fluctuated by 25% and 17%, respectively, when operated at full capacity, with an overall trend of slightly coarser discharge size distribution as the speed decreased. Using a fixed feed rate, the crushers had 4-14% higher production when operating at the optimal speed. Secondary analysis showed that the power draw consistency and magnitude of power spikes could also be improved by optimizing the cone speed. Varying the speed of the crusher can be used to tune the crusher during commissioning, adapt to changing ore conditions over long periods of time or be used as a dynamic input into an advanced control system. each action above would serve to make the crusher(s) more productive, more energy efficient, impove process control and would also have mechanical benefits for the machine

Dec 1, 2013

By F. L. Wilke, J. Fabian, D. Oravec

The task of production planning in ore mining is primarily con¬cerned with the removal of ore blocks within planning periods spread over the life of the mining operation. The investigation of this problem in the past resulted in the introduction of computer based optimizing techniques for production scheduling and se¬quencing. Although these techniques succeed in computing an "optimal" mine output for one planning period, they usually fail in composing a practical and feasible mine plan over the periods in concern. This paper describes conventional production planning based on operations research and the capabilities of a knowledge-based approach. An example of a planning system for the Slovak under¬ground iron ore mine Nizna Slana will be presented. By combina¬tion of these two techniques this system should improve the qual¬ity of planning procedures.

Jan 1, 1996