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By D. Hodouin

The paper reviews approaches to estimate in a real time fashion consistent mass flowrates and assays, using data from the on-stream analyzers and flowmeters of a flotation circuit. Results obtained with one algorithm operating on-line with an industrial flotation circuit are presented.

Jan 1, 1996

By A. K. Fallaw, G. Wang, L. R. Moore, S. Dobson, Y. Xiong, J. Gu

"As ores degrade, mining techniques and chemistries change to meet market demand and maintain product quality. The balance of recovery and grade is a significant challenge in the Crago Process where an anionic collector is used to float phosphate, followed by acid scrubbing, then an amine float to improve product grade. As the grade is a requirement for DAP and MAP production, recovery is the criteria to suffer. Phosphate losses in the amine float can bring overall recovery down by as much as 18%, creating a growing need to think outside the box to improve recovery. This paper will focus on the theory of amine tail recycling and the best methods to optimize the overall phosphate recovery by recycling the tails from the cleaner flotation step. INTRODUCTION In 2014 the total US phosphate production was down 13% over the prior year, from 31.9 to 27.1 Mt, which accounts for 12.32% of the world’s phosphate rock production. Florida and North Carolina phosphate production accounted for 80% of total US phosphate production, which was down from 85% the previous year. This decline is due in part to the closing of the last phosphate mine in Polk County, FL - which had an operating phosphate mine for over 100 years (Gurr, 2015). Another factor contributing to the reduction in contribution from FL & NC is the increasing challenges in beneficiating the remaining ore deposits. The Central Florida mining district has historically been in the Bone Valley deposit, where raw apatite was abundant with P2O5 values as high as 15%. The Bone Valley ore also had characteristics favorable to beneficiation to 27.5-29.7 %P2O5 while achieving recoveries above 86%. The move southward into the Hawthorne Formation has seen the ore feed grade hit some historic lows, and the matrix characteristics pose more challenges to phosphate producers. The Hawthorne Formation experienced lateritic weathering after the Bone Valley formation which altered the apatite to aluminum phosphate minerals, and alteration of montmorillonite to kaolinite, releasing MgO that caused the dolomitization of the top of the Hawthorne limestone (Cathcart, 1966). Elevated levels of dolomite can yield an increase in slurry viscosities, reduce production rates, and increase energy costs in the wet-acid fertilizer process. The MgO will also act to dilute grade, making it more difficult to achieve a standard 18-46-0 product (McHardy, 1981)."

Jan 1, 2016

By Marcus Digre

The autogenous grinding method has been progressively employed in mineral dressing plants during the last 15 years. The term has been used with somewhat different meanings (1), (2), (3). In this paper the author will use it in the most restricted way, for processes where run-of-mine ore (rock) in one step is reduced to a grind product by the action of the ore itself without any other grinding media present. The pebble grinding process where the major part of the ore enters the mill as finely crushed product which is ground further with selected coarse ore pieces acting as grinding media, is not considered autogenous grinding. Processes where a minor amount extraneous media as steel-balls is added to supplement an autogenous mill charge will be called semiautogenous. Other terms need also to be defined. "Mill charge" will be used about the active part of the mill content which performs the grinding, that is the steel balls in ball grinding and the coarse ore pieces in pebble and autogenous grinding. The interstitial nearly finished material is not included in the term "mill charge", and for the wet grinding operations is called the "mill pulp' The term "pebble" will be used for any rounded ore or rock piece in the mill charge whether it is an autogenous or a pebble grinding operation.

Jan 1, 1970

By M. Yavuz

Due to workability difficulties, people have begun to use iron ore much later than gold, copper and bronze. In addition, iron and steel products are the most commonly used metals which are necessary for human life today. It is a fact that iron ore is raw material of the steel production process as known. Iron&Steel sector is plays an important role in the economic development of countries all over the world. Therefore, the amount of production and consumption of steel is one of the basic indicators of industrialization all over the world. The amount of steel consumed per capita of the country is considered as a measure of development. The world average per capita consumption of steel is around 210 kg in 2007 (Yildiz, 2009).

Jan 1, 2010

By Ben L. Seegmiller

How to obtain optimum slope angles for future open pit mines using the rock mechanics approach is the subject of this paper. In the past ten years significant developments in open pit rock mechanics have come about. This has been due to the mining industry's need for the steepest, yet safe, pit slope angles attainable. Requirements for economically achieving slope stability and the actual payoff that may be achieved through stability studies have been previously discussed', by stability engineers. While the emphasis has generally been placed on the concept of "stable slopes" in the past, it is suggested that emphasis now be placed on "optimum slopes" or "optimum slope angles". A definition of an optimum slope angle is one which (1) is as steep as possible and practical from orebody and mining constraint standpoints and yet, (2) maintains the accepted standard of safety defined by a safety factor against failure and/or a probability of failure. In other words, the emphasis is placed on achieving practical stability results as defined by safety and economic considerations, as opposed to simply achieving stability. The essential purposes of this paper are to (1) outline the need for optimum slope angles, (2) discuss the procedures for using the rock mechanics approach in slope angle design for a future open pit and (3) specify the end results that may be achieved by using such an approach. While the basic concepts and recommendations outlined in this paper may be equally applicable to soil as well as rock slopes, the emphasis and procedures have been directed at rock slope angle design.

Jan 1, 1976

By Ronald B. Stone

This paper describes a proposed solution to the problem of mining a 315 foot diameter unsupported sphere at a depth of 2700 feet in a salt dome by conventional mining methods. The proposed solution utilizes many of the varied technologies available to the mining engineer for solving mining and underground construction problems. The following are reviewed in the paper: A. The location of the sphere within the dome as required by construction criteria. B. The relation of the location of the access shafts to the sphere. C. The rock mechanics theory in relation to the salt dome and large size of the excavation. D. The proposed "honeycomb" method of mining which will be a partial answer to rock mechanics stability requirements. E. The equipment which it is recommended be utilized to accomplish the construction. F. The rock mechanics measuring instruments proposed. G. The methods of disposal of the mined salt. Conclusions and areas of further study are outlined in the final statement.

Jan 1, 1968

By Alexander N. Winchell

"The wash ore area on the Mesabi iron range covers a regionof the iron bearing formation extending from Grand Rapids on the west to the Hibbing district, about forty miles eastward. Not all of the developed ore bodies are of wash structure; some are of such grades that they can be shipped direct as merchants able ore. It is safe to say, however, that 65 per cent of the ore is of a possible wash structure and of too high a silica content to be classified as merchantable ore. The increase in the number of washing plants completed each year on the western Mesabi shows that ,the product must be of a structure desirable for furnace operation. The following is a list of plants which were . in operation, under construction, or with plans completed, at the end of 1918:"

Jan 1, 1920

By Y. Lizotte

The purpose of this paper is to describe a stochastic simulation program used to assess several dispatching rules applicable to small scale computerized systems for optimizing truck/shovel productivity. The system studied is semi-automated with a dispatcher communicating instructions by two-way radio. The simulation program is structured on an advance clock approach which enables the insertion of dispatching rules at various points in the haulage net- work. The rules tested include minimize shovel idle time, maximizing immediate truck use and assigning trucks to shovels to meet specific production objectives. A variation of the traditional "Match Factor" is implemented to maintain fleet balance throughout the shift. A mine case study demonstrates how the dispatching rules increase productivity of such semi-automated dispatching systems. Practical problems involved in the implementation of small computerized dispatching systems are also discussed.

Jan 1, 1986

By Ehab Gomaa, K. A. El‑Nagdy

Backfilling material such as tailing (mine wastes) mixing with cement or gypsum has grown throughout the world’s underground mines. However, despite their growing popularity, the typical hydraulic and mechanical fill types utilized in many mines still exist. Deep underground mining has increased due to the lack of commercial minerals nearby. Mine wastes were considered the main part of backfilling to prevent environmental pollution, ground subsidence after mine abandonment, and mine collapse during deeper extraction phases. The cemented backfill technique is the principal technique used in underground mines, which include cement with fly ash and/or filter dust, cement with tailing material and fly ash, gypsum with fly ash, and synthetic anhydrite with fly ash and have been reviewed. It has concluded that a backfilling material must be selected based on further goals, available material near the mine site, and economic factors. This paper analyzes different backfill material mixtures to create a technique that will increase safety in underground mining conditions and foresees an appropriate formula that gives high uniaxial compressive strength. The multiple linear regression (MLR) on the collected data from the experimental works to construct the relationship between the uniaxial compressive strength (UCS) of the mixture and the components of the backfilling and the prediction formula for expected compressive strength was obtained. The results revealed that the predicted regression equation was robust and reliable to predict the (UCS) for the new components of the filling (cement (CE), filter dust (FD), water content (WC), and time (T)).

Oct 3, 2023

By P. Tong-jiang

We studied mineralogical characteristics of the vermiculite samples from seven mines in China. We found three types of interstratified structures in the investigated samples: 1:1 regular interstratified structure, segregated interstratified structure, and random interstratified structure. The vermiculite samples from six mines are mainly composed of phlogopite?vermiculite interstratified minerals, and the samples from the other mine are composed of chlorite?vermiculite interstratified mineral. The samples with phlogopite?vermiculite structure have high contents of K2O, TiO2 and Na2O. The samples with chlorite?vermiculite structure have the highest contents of MgO and Al2O3. The cation exchange capacity of the samples is 17.3?99.0 mmol/100g.The exchangeable cations of phlogopite?vermiculite samples from Weili Mine mainly include Na+ and Ca2+, while those of phlogopite?vermiculite samples from Tongguan Mine mainly include Mg2+ and Ca2+. The thermal expansion ratio of the samples is between 9 and 32. The exfoliated vermiculite products from Weili Mine have the best mechanical strength.

Feb 27, 2013

By C. Leal

Modern production has as goal to reach high and uniform quality in their products. To success with this, it is essential to have a good knowledge of the different variables involved in the process. Investigation or analysis of a process or system has as references the measurements of the variables. These measurements are presented normally in form of data. These data are measured in intervals over time. The aim with measurement of the data in a process is to obtain information about the state of it in order to have it under control. Other goal is to know how the results are affected by the process variables to improve upon product quality, redunding manufacturing cost, better pollution control etc.

Jan 1, 1994

By M. Javier

In business mining, dilution is the result of the operating parameters that occur too often and cause serious consequences to mine performance, questioning TO WHOM BENEFITS DILUTION. Mining persists in changing perception of real meaning of dilution. The lack of interrelation between mineral processes and nature compromises the understanding of dilution; this absence of interrelation occurs due to the misinterpretation of nature, otherwise, Geomimic could be helpful to filling the gap of misinformation. NATURE provides LIMITED metals in low content deposits; it is a challenge to obtain them. Nature never considers dilution. Furthermore, though dilution is a human concept, dilution is accepted and promoted. Reality of dilution is in its errors accumulation that translates into technology level or status applied in nature. It is doubtful that dilution can continue surviving if it is ?meaningless?. It will discourse: Is dilution illegal? If the change occurs in the prediction of mining will prevail a different destiny, it is important to touch the cores of the business; otherwise, it would represent repetition of the same ?negative? effects, as usual. Mining defines many losses during the disturbance of nature, from NPV elaboration to the metal recovery to commerce, demanding BETTER DESIGN. This paper introduces and applies MANAGEMENT BY LOSS, as first steps, to limit risks and uncertainties in mining. As result, the management of dilution will be obtainable under mining practices which promotes its character of SUSTAINABILITY.

Feb 23, 2014

By A. Dell’Era, E. Ciro, C. Lupi

The indium recovery via electrowinning from sulfate baths has recently gained significant attention as it does not present toxic emissions, hermetically sealed system requirements, human health, and environmental hazards. Following previous works related to the optimization process for AISI 316L and Ni cathode, it was observed significant importance of the metal supports on the input and output parameters of the indium electrowinning process from sulfate solutions. Thus, comparing input and output parameters in both cases seems very interesting. Particularly, regarding the input parameters, the attention has been focused on the electrolyte composition, current density, and temperature, while productivity, morphology, and structure have been considered regarding the output parameters. Considering the productivity as the optimal output, the findings for Ni cathode were better than that for AISI 316L in most of the selected conditions studied. In the case of morphology, indium grains appear rounded and dendritic on the AISI 316L, while those on the Ni cathode show stratified lamellar grains. Anyway, the indium deposit obtained on Ni cathode shows bigger grains independently from the used operative conditions with respect to that on AISI 316L. Regarding the structure, it is clearly tetragonal, but preferential orientation, crystallinity, and deformation of the structure strongly depend on the metal support.

Jun 14, 2023

By J. Paul

Mining engineers in charge of open pit mine planning very often face decision making situations dealing with the selection of the most economical method for the removal of overburden. Ripping versus conventional drilling and blasting are the options considered. The choice of a particular overburden removal method depends upon the physic-mechanical properties of the overburden material as well as the various cost factors involved in the process. The analysis of techno-economical factors involved in different methods of overburden removal needs detailed study and investigation by a technical expert. But the expert system "Fragmentation System Design" has been created in a way such that it will help and expedite the decision making process relating to overburden removal in surface mines. Furthermore, this expert system can be used for detailed design aspects of overburden removal in open pit mines.

Jan 1, 1988

By M. A. Giralico

A new generation of hydraulic efficient pumper and auxiliary impeller designs is the result of an extensive research program focused on improving the overall performance of optimized SX/EW plants. Combined with the proper scale-up, these optimized designs will greatly reduce aqueous and organic entrainment losses, reduce or eliminate air entrainment and crud formation, enhance mass-transfer and maximize the overall copper yield. Currently, these new pumper and auxiliary impellers are installed full-scale in numerous plants ranging in flow rates from 90 to 15000 G.P.M. and developed heads up to 51 inches. Operational results reported by the independent metallurgist at each processing plant are reporting the lowest entrainment results in the industry. Further R&D has just been completed on a new mixing configuration that separates the systems mixing and pumping requirements. Results from the system pilot test document further improvements in reduction of both chemical entrainment and crud formation, while keeping mass transfer stage efficiencies.

Jan 1, 1998

By W. C. Foshee

The large volume of water used in coal preparation plants makes water recycling a necessity. Economical cleaning of dirty water usually requires flocculation with an efficient organic polyelectrolyte. This paper discusses identification of optimum flocculant systems. Supporting laboratory data with on-site tests and full scale field trials supplies information necessary for matching the polymer to the plant.

Jan 1, 1979

By E. H. Christiansen

Gem-quality red beryl in the Wah Wah Mountains of southwestern Utah formed as a post-magmatic mineral in a topaz rhyolite flow. Unlike topaz, this beryl occurs along fractures in devitrified rhyolite, rather than in lithophysal vugs. The flow occupies a graben and perhaps a significant paleo-drainage. Beryl occurs at medial depths within the eroded flow, about 170 m below overlying mafic lava flows. Both beryl-bearing fractures and the host rhyolite show an unusual amount of argillic alteration compared with other topaz rhyolite flows. Alteration may be related to the incursion of surface water along shrinkage fractures within the flow. Whole-rock concentrations of CaO within the host rhyolite are very low (<0.01 % to 0.18%) compared with other topaz rhyolites and Be concentrations (about 20 ppm) are about average. Low Ca activities prevented fluorite precipitation and allowed Be transport as fluoride complexes. Beryl probably grew at subsolidus temperatures (-300-650°C), but above the temperature of kaolin development (200-300°C) as fluoride-rich vapors, released by devitrification, encountered fractures and mixed with vapors derived from surface water flowing through the fractures. Beryllium fluoride complexes reacted with water vapor, silica minerals, alkali feldspar, water, and Fe-Mn oxides along fractures to produce red beryl. Continued reaction of the cooling flow with surface water at lower temperatures probably produced a boiling, more acidic fluid that produced the argillic alteration. Consequently, eruption of low-Ca topaz rhyolite followed by entrance of surface water into medial portions of a devitrifying and still hot lava flow appear to be critical factors that led to red beryl formation.

Jan 1, 1996

By J. Villeneuve

Steady-state simulation has proved to be a very useful aid in designing new plants and optimizing existing ones. The algorithms and data definitions of existing simulators often, however, require a great deal of expertise for implementing a simulation-based methodology. The constraints imposed by conventional simulators are explained and the advantages of a new algorithm, the Objective-Driven Simulation, are shown. These advantages are a) an improvement in the simulation results, which enables simplifications of the methodologies used, and b) the possibility of taking into account economic objectives for plant operation, thus extending the range of application of steady-state simulation.

Jan 1, 1992

By Richard A. Grieve

A 63.5 metric tons per hour (70 TPH) demonstration coal preparation plant was constructed on the Iowa State University campus, Ames, Iowa, as a part of the Iowa Coal Project funded by the state of Iowa and administered through the Energy and Minerals Resources Re-search Institute. Processing equipment in the plant circuit includes a heavy media separator, concentration tables, separating and dewatering screens, and conveying equipment. Coal samples of size 907 metric tons (1000 tons) with sulfur contents ranging from 2.5 to 8.75% sulfur from seven mines in the state of Iowa have been pro-cessed in the plant. Sulfur reductions have averaged 35%. With ash reduction averaging 45%. Equipment for advanced fine coal beneficiation research is currently being installed in the plant to include a slurry pretreatment circuit, froth flotation, oil agglomeration, pelletization, hydrocyclones, advanced design thickener and disc filtration.

Jan 1, 1978

By K. J. Shoop

Coal-fired power plants in the U. S. produce approximately 20 million metric tons of Hue-gas desulfurization sludge every year. The sludge mainly consists of calcium sulfite and calcium sulfate. This can be converted to synthetic gypsum, which in principle could be a marketable commodity. However, many Hue-gas scrubbers produce sludges that do not meet the quality requirements of the gypsum industry, and so their sludges must be landfilled as a waste. If a suitable method can be developed for removing certain objectionable impurities from the sludge, it will then be possible to market the material instead of landfilling it. A sludge from a natural-oxidation scrubber was characterized, and the main contaminant was found to be calcium carbonate from unreacted limestone. Based on the particle size and the characteristics of the material, froth flotation was considered as a method for purifying the material. Since no flotation studies have ever been carried out to separate calcium carbonate particles from calcium sulfite or calcium sulfate particles, it was first necessary to select a suitable collecting reagent. Based on Zeta-potential studies, the most suitable reagent was found to be an octadecylamine-octadecylguanidine complex. Results are presented for flotation of calcium carbonate from scrubber sludge using this reagent, in a reverse-flotation process. The best results were obtained when the sludge was first pre-cleaned using a water-only cyclone to remove unfloatable coarse limestone, followed by froth flotation to remove fine limestone.

Jan 1, 1998