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By William M. Kester

Finely sized Upper Freeport coals are beneficiated to reduce ash and sulfur using high-intensity magnetic separation to process both (1) raw, untreated coal as well as (2) raw coal which was pre-treated thermally with steam and air. Substantial, sulfur and ash reduction can be obtained using both approaches to magnetic beneficiation of coal fines, but evidence indicates that pre-treatment which would constitute a costly supplementary step is technically inferior to the direct beneficiation of raw, untreated coal. These bench-scale studies demonstrate that if high-intensity,; high capacity, dry, magnetic beneficiation equipment can be developed and' installed at coal burning power plants or at appropriate points in coal preparation plants substantial quantities of sulfur may be removable from coal after pulverization as a means' to reduce air pollution.

Jan 1, 1965

By A. M. Raichur

Flocculation of fine coal is usually accomplished with the addition of commercially available organic flocculants. Recently it has been shown that biopolymers derived from microorganisms can be used to flocculate coal. The biopolymers flocculate coal efficiently and render the coal surface hydrophobic. The increase in hydrophobicity can be utilized either to separate the coal flocs from mineral matter. It can also be used for reducing the moisture content of fine coal. In this regard, flocculation and settling tests of fine coal with biopolymers and synthetic flocculants was undertaken and the results are discussed here. Also, a transport model was developed for the time-dependent settling tests for fine coal.

Jan 1, 1996

By J. D. Grace

[Screening by centrifugal force is an unique, subject, for with the exception of only one vibrating screen presently on the market, all vibrating screens depend upon, gravity to pass material through a sizing mesh or screen cloth. This one screen that sizes by centrifugal force and utilizes gravity only to convey materiel along the screen, is the SYMONS V-Screen. This screen was designed by Loren Symons, a member of the family that has contributed so much to the metallic and non-metallic mineral processing industries. Among Symons' other outstanding contribution to these industries are the original Cone Crusher which revolutionized reduction crushing practice, the first high-speed horizontal vibrating screen, the original Rod Deck Screen, and one of the earliest vibrating Bar Grizzlies.]

Jan 1, 1965

By R. E. Hucko

The principal thrust of the U.S. Department of Energy (DOE) Coal Preparation R&D Program is to develop technology to reduce the ash and sulfur contents of United States coals to levels such that the resultant product can be formulated into a high quality solid or slurry fuel that could replace oil or natural gas in both new and retrofit applications. Specifically, the objective is to develop and refine cost-effective physical and chemical beneficiation processes to extract 85-95 percent of the total sulfur and ash. The Coal Preparation program is implemented by the Pittsburgh Energy Technology Center (PETC) and is conducted both in-house and by a cross section of industrial organizations, universities, and national laboratories. Research is subdivided into three areas -coal characterization, beneficiation, and ancillary unit operations. This paper will provide a brief overview of many of the research projects being carried out in these areas in fiscal year 1984.

Jan 1, 1984

By B. C. Darst

Developments in the agricultural use of potassium (K) have been based solely on the essential role K plays in crop production. Crop plants cannot complete their normal life cycle if K is deficient or absent. In fact, no essential plant nutrient other than nitrogen is required in greater quantities. Table 1 shows the amounts of K some crops take up from the soil. Although the exact functions of K in the plant are not well known, its primary role seems to be tied to plant metabolism. Potassium is vital to the process of photosynthesis. When K is deficient, photosynthesis declines, but respiration increases. These two K-deficient conditions. . . reduced photosynthesis and increased respiration ... lower the plant's carbohydrate supply, the end result being poor agronomic crop production. Potassium is also essential to several other plant functions, including the following: 1) Protein synthesis. 2) Water use efficiency, through the influence of K on stomata opening and closing, to maintain the turgidity in plant leaf cells. 3) Translocation of heavy metals such as iron and zinc. 4) Ionic balance. 5) Control of enzyme reactions within plants.

Jan 1, 1985

By Y. H. Alghamdi, A. D. S. Gillies

"INTRODUCTION Background Diesel Particulate Matter (DPM) has been a critical issue during the last decade in underground mines. This problem is threatening the health of mine workers, as well as the mine’s productivity. It has been confirmed that the diesel engine exhaust is the main source for the diesel particulate matter (DPM), and that it has the highest impact in raising carbon monoxide, carbon dioxide, oxide of nitrogen, and hydrocarbons in the underground environment. Miners who are exposed to this kind of emission are at high risk for developing lung cancer and other lung diseases. The Mine Safety and Health Administration (MSHA) has issued standard rules to regulate diesel emissions in underground mines. The final ruling confirmed in 2008 that the total carbon should not exceed 160 µg/m3. (MISHA, 2008) Monitoring DPM in underground mines has become important to ensure compliance with the MSHA regulations. There are many different types of DPM monitoring systems that are currently being used in underground mines. Two methods are typically used for DPM sampling: the personal sampling method or the direct exhaust sampling method, which takes a direct sample from the engine’s tailpipe. Many mines do not recommend using the direct exhaust sampling method since it involves complex measuring equipment and procedures, as well as it is not regulated in the United States or Canada. Thus, the personal sampling method is the preferred method in many mines when taking DPM samples. Even this method includes many variations, such as the Respirable Combustible Dust (RCD) method and the method devolved by the National Institute for Occupational Health and Safety NIOSH 5040. The NIOSH 5040 method is the preferred method overall because it gives more accurate measurements compared to the other methods. This method does not allow organic carbon sources other than those coming from diesel engine exhausts to interfere with the measurements, which otherwise would lead to overestimating the actual amount of the DPM in the mine environment. An impactor feature in the cassette, which holds the samples in the instrument, characterizes this method. Since the diesel particles are less than 0.9 micron, this impactor does not allow particles more than 0.9 microns to be collected in the cassette filter. The cassette is then analyzed in a lab and the concentrations of organic carbon (OC), elemental carbon (EC), and total carbon (TC) are determined. Lately, the National Institute for Occupational Safety and Health (NIOSH) has developed a new instrument that can use the same concept of NIOSH 5040, but with instant measurements of elemental carbon. It utilizes laser radiation with the cassette so it can give a real time measurement. The real time measurements give instant information about the underground environment that will allow the mining engineer to take immediate action and enact plans instead of waiting for results from the laboratories where NIOSH 5040 method may take several weeks to get the measurements."

Jan 1, 2016

By P. C. Clark

This paper is an overview of the requirements and concerns for minerals and pigments used in papermaking. The first part of this paper deals with mineral or pigment filling in the actual papermaking process. The second part deals with the pigment or mineral properties that are important in today's coating processes.

Jan 1, 1993

By G. L. Black

Choosing a mining method for an underground ore body is a complicated and often iterative process. Advances in technology give the design team an overwhelming array of possibilities for methods and equipment. Hecla's recent discovery of the deep Gold Hunter ore body has given the staff at the Lucky Friday Mine the exciting challenge of determining the optimum mining method. Taking an ore body from prospect to production requires traditional resource characterization, including drilling, delineating and modeling. Developing the mining plan is an evolving process, changing with each new piece of information as the project progresses through exploration and development.

Jan 1, 1998

By C. C. Stewart

Jim Walter Resources, Inc. operates four underground coal mines in Alabama. In 1986, during longwall recovery operations, sparks from a torch ignited methane that migrated onto the face after a roof fall. The fire quickly spread to the gob at the tailgate end of the longwall. The fire was successfully "area" sealed and mining operations resumed after five weeks. However, several problems were encountered during this process. This paper describes the events following the fire, methods used to control the situation, problems encountered, and steps taken to ensure preparedness for any future occurrences of this type.

Jan 1, 1993

By Benjamin C. B. Hsieh

Many processes in the hydrometallurgical and chemical industries require the separation of dissolved material from suspended solids. Counter current decantation (CCD) with thickeners is one of the methods generally used. The process engineer needs a quick and accurate CCD calculation method. Several theoretical 1-12 CCD calculation methods are available in the literature . The simultaneous 1, 2 equation method for a complex circuit as used would take too long to solve the problems. Approximate equation method1 is not accurate and is for simple cases only. A shortcut method developed by Counselman3 contains no mathematical equation, and thus is not suitable for computer programming. Based on Counselman's method, Woody4 derived two simple equations in terms of percent soluble loss for two typical examples. Scandrett5 included a term for mixing in his formulas. This mixing efficiency was defined by Murphree6. Another method which depends on making volume calculations instead of using weights is presented by Mastin8 and Cahalan9. None of these methods is related to dissolution and pre¬cipitation reactions. Chen 10,11 demonstrated his methods for counter current leaching. His results are calculated from the general solution of a derived linear difference equation for constant underflow, and from the solution of a derived non-linear Ricatti difference equation for variable underflow. This paper concerns derivation of a general equation for CCD washing with provisions for adding and withdrawing the streams, and for leaching (dissolution) or precipitation reactions. These equations take several forms depending on the input information available. A set of simplified equations for continuous counter current washing and leaching is derived for determining:

Jan 1, 1972

By J. D. Noll, J. A. Organiscak, A. B. Cecala

Significant strides have been made in optimizing the design of filtration and pressurization systems used on the enclosed cabs of mobile mining equipment to reduce respirable dust and provide the best air quality to the equipment operators. Considering all of the advances made in this area, one aspect that still needed to be evaluated was a comparison of the efficiencies of the different filters used in these systems. As high-efficiency particulate arrestance (HEPA) filters provide the highest filtering efficiency, the general assumption would be that they would also provide the greatest level of protection to workers. Researchers for the U.S. National Institute for Occupational Safety and Health (NIOSH) speculated, based upon a previous laboratory study, that filters with minimum efficiency reporting value, or MERV rating, of 16 may be a more appropriate choice than HEPA filters in most cases for the mining industry. A study was therefore performed comparing HEPA and MERV 16 filters on two kinds of underground limestone mining equipment, a roof bolter and a face drill, to evaluate this theory. Testing showed that, at the 95-percent confidence level, there was no statistical difference between the efficiencies of the two types of filters on the two kinds of mining equipment. As the MERV 16 filters were less restrictive, provided greater airflow and cab pressurization, cost less and required less-frequent replacement than the HEPA filters, the MERV 16 filters were concluded to be the optimal choice for both the roof bolter and the face drill in this comparative analysis case study. Another key finding of this study is the substantial improvement in the effectiveness of filtration and pressurization systems when using a final filter design.

Aug 1, 2016

By B. Morris

This presentation will describe the process by which the Quebrada Blanca (QB) copper project in northern Chile was financed. It will also show how a relatively junior mining company addressed the problems created by its inability to provide its share of the equity funding and the guarantees required by the project lenders. QB is located in the semi-arid Andean highlands of northern Chile, 170 kilometres southeast of the port of Iquique and 30 kilometres west of the border with Bolivia, at an altitude of about 4,300 metres (14,000 feet). Figure 1 depicts the project's location. The QB orebody is a secondarily enriched porphyry copper deposit containing reserves of 85 million metric tons grading 1.3 percent copper. Underlying the enriched zone is a significant primary ore zone containing several hundred million metric tons grading about 0.5 percent copper. In the late seventies and early eighties Falconbridge and its affiliates spent $20-30 million dollars exploring the deposit and conducting feasibility studies. For a variety of reasons they decided not to develop the property which was returned to its owners, Empresa Nacional de Mineria (ENAMI), which is a Chilean state mining corporation. In 1988 ENAMI announced its intention to privatize the property through a public bidding procedure.

Jan 1, 1993

The past decade has seen remarkable progress by the railroads both in equipment and concepts in the handling of dry bulk. materials. While such shipments have always been an important part of the traffic handled by the railroads I little was done to improve the efficiency of handling or toward attempted optimization of equipment design before 1960. Several developments at about that time turned attention to this important segment of railroad traffic. One was the construction of a successful coal slurry pipe-line. Another was the promise of substantial economy in electric power transmission by ultrahigh voltage systems and finally, came the growing technological and economic feasibility of nuclear fuel electric generating plants. Each of these developments was a threat to the coal traffic of the railroads --the most important single commodity they handled in terms of revenue and tonnage. By the mid-1950's I Southern Railway management had become most concerned with its growing investment in freight car equipment and the declining revenue productivity of the capital employed. Additionally I there was substantial concern with the loss of business and potential losses in the area of the railroad's greatest economic advantage --bulk commodity movements. In 1958 a small team was established to study this problem. They arrived at two conclusions. The first conclusion was that within limits of maximum gross allowable weight on rail the lowest unit net capacity cost of investment came at maximum allowable gross weight per car unit. The second conclusion was that with a high degree of utilization costs per weight unit transported could be reduced to the pOint where

Jan 1, 1971

By L. Michael Kaas

Any increasing number of restrictions are being placed on mining management's ability to pursue profit. Raw materials pricing, the cost of capital equipment, labor cost, and overhead costs, are becoming more difficult to control. Cost reduction is one of the few remaining areas in which management may still exercise its profit making ability. Equipment maintenance is an area where mine and mill management can readily reduce costs and increase profits. Why is this possible? First, maintenance costs comprise a large portion of total operating cost. Thirty to sixty percent of the operating cost dollar is not unusual. Even a relatively small percentage reduction in this cost represents a very sizeable increase to mining profitability.

Jan 1, 1967

By John F. Abel

Convergence measurement across the 17.4 m (57ft) high shaft station/loading pocket at Mt. Taylor provided continuing verification of stability and safety. Three levels of instrumentation, consisting of three lines each, were installed and monitored. The instrumentation showed that the flexible lining restrained the adjacent rock. The flexible lining consisted of pea gravel with neat cement between rock and liner plate, wooden crush blocks between liner plate and steel ring beams. The loading pocket is elliptical, 11.6 by 9.6 m (38 by 31 1/2 ft) I.D. The crush blocks were designed to allow 15 cm (6 in.) of convergence. Maximum predicted convergence was 7.0 cm (2 3/4 in.) and 5.7 cm (2 1/4 in.) was measured. Convergence measurements also demonstrated decreasing deformation with respect to elapsed time and distance from the measurement station to the temporary bottom of the shaft excavation.

Jan 1, 1984

By E. J. Ostrowski

The history of ironmaking dates back to 4000 BC when an open forge was used to produce a sponge iron from a heap of ore and charcoal. Even at this early date, man recognized the need for a fuel and a reducing agent. As time passed, man developed new methods of producing iron; however, these developments were centered on the mechanical aspects, and as a result, a furnace evolved which is now known as a blast furnace. During this period of evolution,' man struggled with the only fuel he knew - charcoal. Some 5600 years passed before any attempt was made to use coal as a fuel for the blast furnace. The use of coal had its beginning in 1619 when Dud Dudley of England first attempted its use in the blast furnace; as a-fuel and as a reducing agent. Coal charged to the top of the blast furnace was not satisfactory. The volatile matter of the coal choked the flues, and also the poor, strength qualities would not support the weight of the ore. Breaking up of the coal compacted the stock column to an impervious mass. One hundred and sixteen. years later in 1735, Abraham Darby of England introduced coke as the fuel and reducing agent in the blast furnace. The acceptance of coke as a fuel for the blast furnace was not spontaneous. As late as 1870, one-half of the pig iron product of the United States was made with anthracite coal, 30 per cent with raw bituminous coal and coke, and 20 per cent with charcoal. However, by 1910, 96.2 per cent of the blast furnace product was made with coke, 2.4 per cent with anthracite and coke admixture, and 1.4 per cent with charcoal. Coke became the standard fuel in the blast furnace. As the art of ironmaking progressed, more pig iron was produced and more coke was consumed. Coke oven capacity was progressively increased. In 1910, there existed approximately 4,000 coke ovens; in 1960 there was approximately 15,000 ovens. This increase in coke oven capacity was necessary to feed the mammoth appetite of modern blast furnaces.

Jan 1, 1962

By P. C. van Aswegen

The Bacterial Oxidation (BIOX®) process for the pre-treatment of refractory ores for gold recovery developed by Genmin, the mining division of Gencor, has been operating successfully at the Fairview mine since October 1986. The continuous operation of a pilot plant at Genmin Process Research has resulted in further process developments to improve plant operating efficiencies. These new developments which include a higher solids content of the pulp feed to BIOX®, lower retention times, higher operating temperatures, lower power utilization for oxygen dispersion .and reduced nutrient addition have all been successfully implemented on the Fairview plant.lt has furthermore been confirmed that the arsenic precipitate formed in the neutralization of effluent solutions complies to the United States of America EPA standards. Continuous cyanidation pilot plant work conducted on BIOX® product has indicated that cyanide consumption can be drastically decreased if a continuous flowsheet is implemented in preference to a batch leaching system.

Jan 1, 1991

By P. Shang

Fly ash and zeolite have strong absorption to cations since their porous microstructure. The porosities of fly ash and zeolite can also be increased by modification, which improves the absorption of the materials. This research showed that the effects of modified fly ash and zeolite to remove ammonia nitrogen from rainwater. The optimal reaction time, additive amount of materials, and pH value of the stormwater to remove ammonia nitrogen were experimentally determined. For modified fly ash, the optimal removal rate of ammonia nitrogen from 100 ml stormwater was 74.41% with the addition of 10.0g fly ash, 1.5 hours of the reaction time, and 8 of pH value. To the modified zeolite, the optimal removal rate of ammonia nitrogen was 51.22% at the reaction conditions of 2.0g of zeolite, 1 hour of reaction time, and 7 of pH value.

Jan 1, 2010

By R. L. Eppley

The Blacklick Creek Watershed Association was awarded a $158,000 Growing Greener grant from the Pennsylvania Department of Environmental Protection in 2002 for the design and construction of a sulfate reducing bioreactor (SRBR) cell to treat acidic discharge from the Judy 14 abandoned underground coal mine near Indiana, PA. The vertical flow SRBR was designed to treat 38 liters per minute of MIW containing elevated concentrations of aluminum and iron. Other treatment systems at this site plugged due to aluminum precipitates; this problem did not occur in the SRBR. The bioreactor has been periodically overloaded with flows up to six times the design rate. To date, the only maintenance performed on the unit has been the addition of hay to the surface of the unit in response to less than expected performance. The periodic hay additions appear to have restored the SRBR to nearly post-construction levels. Since construction, the SRBR has treated about 136,000 cubic meters (36 million US gallons) of MIW.

Jan 1, 2010

By David A. Lee

It was estimated in Chemical Week1 that the uranium fuel requirements for the U.S. Electric Utility Industry by the mid 1980's would be about four times that-of what it is today. This corresponds to approximately 45,000 tons per year of 'yellow cake' - of which a good portion is represented by ammonium diuranate - vs. the 11,700 ton total estimated for 1975. Perhaps just as significant is the 40-fold increase in thirty years projected for the entire world since 1970. Thus by the year 2000. 'yellow cake' production could be in the order of [3]50.000 short tons annually.2 'Yellow cake', so named because of its inherently bright yellow color, is a finely divided precipitate that can be formed after the leaching step when refining uranium ores. Feed solids enhancement then occurs to at least 50% by weight using filters or centrifuges This is followed normally by drying and then calcining with the conversion of ammonium diuranate to triuranium octoxide represented by the following equation: [9 (NH4)2 U2 07 heat 14 NH3 7 + 15 H2O7 + 2N2/ + 6 U308 4] Theoretically, assuming 100% conversion every 100 kgs. or 100 lbs. of ammonium diuranate will result in 90 kgs. or 90 lbs. of triuranium octoxide.

Jan 1, 1976