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By R. R. Klimpel

This paper describes a series of mechanical flotation cell results run with various chemical reagent schemes designed to economically improve the flotation performance associated with selected industrially available coals. The emphasis is on the identification of practical flotation methods of processing coals containing unusually coarse and/or fine feed sizes, of increasing the recovery of oxidized and/or difficult to float coal, and of increasing the selectivity of coal over pyrite in high sulfur coals.

Jan 1, 1991

By C. Timothy Shaw

Traditionally, only the large mining companies have maintained specialist departments in such areas as Rock Mechanics, Ventilation and Safety. To the small companies this has been a luxury that they could ill afford. Any work required by such companies in these areas, more complex than could be handled by the existing staff, was done by consultants. This situation is changing though and there is a need arising for many specialist departments. These changes are partly being brought about by the effects of inflation as the ever increasing costs are causing more and more operators to increase the size of their operations in search of economies of scale. In addition though the plethora of new laws and regulations are creating a need for many more specialists in all areas of mining in order to ensure compliance. The abovementioned factors, added to the existing Pattern of mines endeavoring to improve the working environment for their labor force, both for reasons of practical labor relations and also due to further legislative pressures, have thus created a climate where, in the near future, departments such as Rock Mechanics, Safety, Ventilation, Environmental Engineering and Subsidence Control will be commonplace in mining companies. It will no longer be practical to function without such services. Many mining companies already maintain such departments and this has particularly been true of the big mining groups of South Africa. From the experience gained by many of these large companies with specialist departments, it is clear that the maintenance of a cadre of experienced, competent professionals in such a department has not always been easy. It would seem from the experience gained that one can generalise and state that graduate mining engineers tend not to view specilisation as an optimum direction for their career development. It is of course true that many professionals, especially those with higher than a bachelors degree, do view these areas as valid career options, but even here experience shows that wastage is high. The time therefore seems to be ripe to take a look at this area in some detail to see whether reasons for the problems can be isolated. Working from that some suggestions can be made as to directions in which improvements might be made. If the challenge of the demands of the new regulations are to be met then such improvements must be made.

Jan 1, 1980

By J. Raatikainen, I. Auranen

"INTRODUCTION Sorting technology has advanced rapidly recently. Of the two possibilities particle sorting has advanced especially in introducing new sensors and the use of multiple sensors. The analyzing and computing lead times have also shortened. This has made it a viable technology option for many applications but not for the most important sorting task at a mine; the run-of mine ore. Bulk sorting, however, has advanced in smaller steps, even if the technology has the capability to tackle the run-of-mine ore and offers a high potential to bring mines substantial economic benefits. The sensors, which are useful are restricted by the difficult operating conditions or by the ore characteristics. One of the important features of run-of-mine sorting technology is the major material handling infrastructure required. The capital expenditure can be substantial requiring good understanding of the sortability curve (grade-recovery curve) behavior of the ore. This paper discusses one industrial case, where substantial amount of data measured from the ore feed belt has been obtained. This data was then analyzed for the grade recovery curves obtainable from that ore with sorting. EXPERIMENTAL The XRF measurement used was the FCA device from IMA Engineering (Fig.1). It is a specially built version of XRF designed to operate with coarse material. The measurement was situated at the main belt conveyor taking ore from the primary crusher to the stockpile. The crushed ore was about 80% -300 mm at a capacity of 1100-1200 tph (Fig.2). Measurement times were varied from 30 seconds to a minute. Measurements were obtained over several months.As the XRF is a surface distribution measuring technique, the measurement was first tested upon accuracy and reproducibility against plant daily wet chemical assays and against on-line Courier feed analysis. As there is a varying delay in the ore stockpile, the delay time was used as a variant in the validation. Different measurement times were tested for accuracy. A one minute measurement time gave a total measurement relative standard error, which was both for Cu and Ni below 3%. The results showed also very robust correlations; for Cu, the correlation coefficient was R > 0,94 for one minute measurements over three months and R > 0,86 for Ni respectively. Fig 3. Shows a measurement period of two hours showing substantial feed grade variations (given as relative value; 1.0 represents the mean value during the measurement month)."

Jan 1, 2018

By J. L. Fuller

Thousands of mine air samples are taken underground each year by MSHA inspection personnel in order to further assure that miners have a safe and healthy environment in which to work. While most air samples are taken with stain tubes, many samples are obtained in evacuated containers and returned to a laboratory for more accurate analysis on a gas chromatograph. In order to enhance the accuracy, reliability and repeatability of the samples taken with evacuated containers, improved procedures have been developed, which are described in this report, for filling two different types of evacuated sample containers using either mechanical or electrical pumps. In those instances, such as when sampling strata gases in drill holes, where mathematical calculations may be required for proper sampling, example calculations are provided. The use of a third type of evacuated container, which is generally restricted to non-specific sampling of the ambient mine atmosphere, is also described.

Jan 1, 1986

By J. R. Evans

Mining claims must have a discovery of a valuable mineral deposit to be valid. When required, a Federal government mineral examiner makes a determination of validity and recommendations thereof to authorized management officials. The examiner should show whether or not an existing mining operation, or a proposed operation have economic viability. This is accomplished through an analysis of legal entities, land status and use, geologic and mineralogic relationships, and mining, milling and processing techniques considered in an appropriate economic evaluation framework. A framework involves market and market entry studies, reserve analyses, all costs analysis, royalty buyouts, tax structure, discount rate of return, and escalation and risk factors. An income approach to value is then used by means of a simple or complex discounted cash flow (DCF) analysis to certify validity. Whether one claim is owned by a single miner, or hundreds of claims are owned by a large corporation, thorough, fair, consistent, and appropriate economic concepts should be applied by the mineral examiner.

Jan 1, 1993

By R. G. Graber

Field testing of GPS mining applications has confirmed the technical and operational viability of GPS for precise, centimeter-level positioning in harsh taconite environments. GPS hardware has provided consistent availability exceeding 90%, with precision in certain applications of ± 0.07 foot at 95% confidence levels. Despite these technical successes though, challenges persist in achieving effective GPS integration. These challenges include the acceptance of new job tasks by mine personnel, the capacity of typical mine data communications infrastructure and the need to design GPS interfaces for new mining equipment.

Jan 1, 1998

By T. J. Dudek

To be competitive in automotive applications, polymer composites must be processable by high production rate processes like injection molding (IM), reaction injection molding (RIM), structural rim (SRIM) and compression molding. With current fiber reinforced composite materials, performance properties are sometimes compromised to make them compatible with these processes. This is done by decreasing the amount and length of the reinforcing fiber and the viscosity and molecular weight of the polymer matrix. Sheet molding composite (SMC) and thermoplastic polymer blends are examples of polymer composites which are cost effective in many applications and meet the high speed processing requirements for automotive parts.

Jan 1, 1993

By Steven A. Tesdahl

Maintenance means keeping equipment running or restoring it to operating condition. However, the 21st century will usher in a broader need for equipment management, a cradle-to-grave strategy to preserve equipment functions, avoid the consequences of failure and ensure the productive capacity of equipment. Profitable future mining operations will have reduced the 35% of operating costs typically spent on maintenance and the unfavorable impact of downtime that often multiplied these costs by 300%. They will survive those operations that tried to carry outdated "maintenance" thinking beyond the year 2000. These surviving operations will have applied modern management techniques, technology and information to align the efforts of people with the needs of equipment. Future managers will use equipment management as an integral part of an overall production strategy. They will see it as a means of raising productivity, improving performance and minimizing downtime to maximize profitability. This global thinking will characterize all operations planning to survive in the competitive world of mining of the next century.

Jan 1, 1998

By E. H. Bentzen

The purpose of this paper is to explain the production of sand for glass manufacturing and the reasoning behind the sand specifications set by the glass industry. In order to discuss the production of glass sand, there is a need to understand what glass is and how it is made. Therefore this paper discusses glass, as well as sand beneficiation.

Jan 1, 1977

By B. Anamaeric

Economic, environmental and operational disadvantages of the traditional blast furnace process has led to the development of direct smelting reduction processes, including those that utilize self reducing/ fluxing dried greenballs as iron oxide feed materials. This is mainly due to improved carbothermic reduction, carburization and reaction kinetics. In this paper, the morphological changes of the greenballs as they transform to pig iron nuggets are examined over time at a constant temperature of 1,400° C. The products produced after each treatment were characterized using optical microscopy, scanning electron microscopy/energy dispersive spectroscopy and point counting/image analysis. The changes in the percent metallized area, wustite dendrite and slag matrix content of the structures were calculated. It was determined that the transformations were initially controlled by dissolving and containment of iron oxides in the molten slag and their consequent reduction to iron, followed by coalescence of the metallized areas. The final transformations were controlled by the carburization of the metallized areas.

By B. A. Bancroft

A quality assurance program consists of all those activities aimed at providing confidence to the purchaser that the suppliers quality system will provide a product that will satisfy the purchaser's stated quality requirement. An organizing principle is necessary for prioritizing the quality control activities of quality personnel in the face of a myriad of technical possibilities, data-analytic applications, and an overwhelming number of possible activities promoted in the literature and by quality "gurus". The organizing principle I like is that quality assurance exists when those involved in the quality process: (1) know what they are supposed to do, (2) can tell if they are doing it and are set up to continue doing it and, (3) if they are not, they can remedy the situation in a timely fashion. Any incremental activity which facilitates this organizing principle is a continuous improvement activity. That activity which has the chance to facilitate this principle to the greatest extent is the next one to work on. In these days of lean corporate and regional staffs it is as important to know what not to work on as it is to know what to work on. In this paper I shall discuss in general terms the implications of this organizing principle for the design of Quality Assurance (QA) Programs for coal mines and also provide some comments about the application of Statistical Process Control (SPC) methodologies in the coal industry.

Jan 1, 1994

By Wayne D. Gould

Planning for a project does not start with the announcement of the approval for a project. Planning actually begins when the project is only a prospect and it involves the years of experience of many people because their expertise influences the final decisions. In partial anticipation of the Pinto Valley project, as well as a search for improvement in the Copper Cities operation, two projects were undertaken. The first project was to substitute one 26" cyclone for three 20? cyclones in the single stage grinding circuit. The second project was to replace the Hunt air flotation cells with 300 cubic foot mechanical cells. The 300 cubic foot cells were just being introduced, consequently two types of cells were selected for testing. The results from both projects influenced the decisions on equipment for the Pinto Valley project.

Jan 1, 1975

By James A. Clem

Approximately 2,000 years ago, the Lord Admonished the Scribes (Lawyers) and Pharisees (Religious leaders of that time) that they had paid the tithe but had omitted the weightier matters of law, Judgement, Mercy, and Faith. (Matt. 23:23). I want to talk about "The Weightier Matters of Law." In a situation where big government is trying to have an effect on even small details of a work activity, otherwise simple situations become complex. Regulations are written to such detail that constant compliance with strict interpretations can be a nightmare--not to mention off the target of the intended purpose for the regulation. One soon re- cognizes the oneros characteristics of Federal statues

Jan 1, 1979

By B. S. Hulvey

Thin support liners are becoming more accepted and being developed with improved properties because the mining industry as a whole has been offering underground safe test trial sites. This is because of the huge potential for such products. Recent developments tend to indicate that the technology is “coming of age” and these are discussed in this paper.

Jan 1, 2003

By James A. Jessop

The Bureau of Mines is investigating the use of geophysical methods to determine rock mass characteristics, particularly rock quality, lithology, and fracture parameters that are important for determining the feasibility of in situ leaching operations. As part of this research, two Bureau-developed crosshole geophysical systems are described that can be used for site investigation and rock mass characterization. Results are given for performance tests at field sites in Arizona and Texas and for correlations between the crosshole seismic data with fracture frequency, rock quality, and lithologic variation. Recommendations are made for using elastic waveform propagation characteristics and dynamic elastic properties for improving rock mass characterization in the geomechanical assessment of in situ leaching deposits.

Jan 1, 1990

By B. Gigas, M. Preston, M. Giralico

Optimized mixer settler designs will now handle total flows of over 6,000 m3/hr.Computational Fluid Dynamics (CFD) is a timely and predictable tool for design development. Lightnin has the capability of using numerical analysis methodology to evaluate flow patterns and phase separation. CFD can show performance differences between changes, in mix tanks, in settler geometry, and in liquid depth, against variable flow rates. Understanding the differences allows the development of optimized designs. This paper focuses on the major design components of the mixer settler and how technological advances will lead to further improvements, when designing for today’s largest flow plants.

Jan 1, 2004

By A. K. Bhowmick

Size reduction is very energy intensive and is the single most power-intensive operation in mineral processing plants. Research has shown that only a small part of the energy is utilized efficiently. One of the major thrusts of all equipment manufacturers has been to improve this efficiency. Choosing the right equipment to maximize energy utilization in any comminution application has always been the utmost criteria. Due to the high energy cost and depletion of good grade minerals, it is becoming essential to optimize all the subsystems within a given comminution system for the overall economic success of such ventures. Bradley Pulverizer Company of Allentown, Pennsylvania recognized this and started offering its Feeder Controller in 1988 for automatic feed control. After its first successful operation, Bradley made this as a part of all of their grinding system standard offering. It was also recognized that the Feeder Controller was just a beginning and more automation and controls would be required for an overall, efficient grinding system.

Jan 1, 1993

By KOKOWSKI J., RUDZIŃSKI Ł.

The LUMINEOS network was established in 2013 to monitor mining-induced seismicity in Legnica-Głogów Copper District (LGCD), located in south-western Poland. Since the starting time, the network was improved and today consists of 17 seismometers and 10 accelerometers. Up to now, the strongest recorded earthquake in the region had Mw4.0. Both raw seismic data and earthquakes catalog for events recorded by the LUMINEOS network are fully open and available on the EPISODES platform (https://tcs.ah-epos.eu/#episode:LGCD). During the last 7 years, the network improvements gave us a possibility to increase location accuracy for shallow mining events. This accuracy is influenced by factors such as the configuration of seismic stations, noise level at seismic stations, and the influence of the velocity model. Here we encountered two main issues which are worth to discuss. The first one is the low detection threshold of two seismic stations and their significant impact on the location errors. The second one is the large uncertainty in the S-wave picking. Even though S-waves are not so clearly visible on seismograms, they are very helpful in the estimation of source location and strength of seismic events in the region. In our work, we present the history of LUMINEOS network and corresponding improvement on location accuracy as well as the influence of noisy stations on the error distribution and how it is connected with location results. We also investigate the effect of the S-wave phases and how they are related to the accuracy of the earthquakes locations in the network.

Apr 26, 2022

By Joseph J. Garbarino

World demand for phosphate fertilizers has grown at an average annual rate of between 6 and 7 per cent over the past 10 years. In the next five years world demand is expected to at least continue to grow at that rate. Also, the continued need for improved fertilizer materials, coupled with improvements in fertilizer technology, have placed added importance on the use of phosphoric acid as a starting material for high analysis phosphate fertilizers. This demand for phosphates and phosphoric acid must be met by increased production. Increased phosphoric acid production also brings increased demand for chemical processing agents including foam control agents. We at Arizona Chemical Company have closely followed the phosphate fertilizer industries needs. Arizona Chemical Company has been an important supplier of flotation agents to the phosphate industry, primarily from its Panama City, Florida plant. We have also recognized the important role played by foam control agents in the wet-phosphoric acid manufacturing process. We feel it is the responsibility of the supplier of foam control agents to offer specifically designed products that are highly efficient and economically useful. The difficulties involved in evaluating foam control agents in the plant are recognized. Owing to the large number of variables present, and the difficulties in controlling these variables during the period of a plant trial, plant evaluation of a large number of foam control agents is impractical. We have attempted to develop a practical, reproducible, and yet rapid, laboratory evaluation test which correlates with plant performance.

Jan 1, 1966

By Francis Martino

Just as coal producing mines are faced with various handicaps which control the quantity of coal produced and sold, the subsequent user of that product is faced with parameters that impact the optimum utilization of coal. Traditionally, the industry focused on the quantity of mineable coal in a reserve. The mine planning development was primarily concerned with two important criteria: (1) safety and (2) the productive efficiency in a quest to produce the lowest cost coal.

Jan 1, 1982