Search Documents

By J. Hahn

Modern high-performance disc filters such as the BoVac Disc Filter have set new standards in applications where large capacities of solids, liquids and air have to be managed through the filters. These disc filters have an enormous hydraulic capacity. For applications in mineral processing - with a special focus on tailings – which typically have high solids throughputs but low filtrate and air flows, this capacity can be used to expand the filtration area while maintaining the benefits of very good cake discharge even with thin cakes (4-5 mm) and a high filter speed. Research work over the last century has proven that increasing the filter area should be achieved by increasing the disc diameter. Because adding more discs leads to big problems with the cake discharge. However, as the disc diameter increases, the filter segments become longer and heavier. A suitable compromise was therefore found by doing both. The result is the first vacuum disc filter that offers significantly more than 300 m² of filtration area, but has no more than 6 discs.

Feb 1, 2023

By T. P. McNulty

During the last decade, many exhaustive studies have been made of process energy requirements for the production of various metals and materials. Some excellent technical papers and text books have resulted, and some of these are included in the bibliography of this paper. These studies were, of course, prompted by the economic pressures which resulted from the beginning of the "Energy Crisis" in 1973. Our intensified consciousness of the cost of energy led, then, to a greatly improved understanding of the energy consumption attributable to individual mining, processing, and refining steps. It is worth noting, however, that an awareness of the cost of energy is not new and that efforts to minimize this cost were an important part of sound mine and plant management practice throughout the earlier days of our industry. One only has to read a few accounts of mining operations around the beginning of this century to develop an appreciation for the cost of supplying wood, coal, fuel oil, or electric power to remote locations.

Jan 1, 1983

By V. D. Hanson

When maintenance of a plant or operation is under discussion immediately three "M's", all in short supply, are brought to mind - money, men and markets. This paper will present what currently is being done at our plants and its effect on the 3 "M's". Examination of coal realization figures (F.O.B. Mine) from 1945 to the present reveals the fact that open and free competition can and will meet market conditions. The industry, without benefit of advantages afforded tax and transportation wise to oil and gas, remains the backbone of the energy market of United States. Figure No. 1 shows the realization figures from 1945 through 1962 compared to the hourly earnings. Note that through 1945 to 1948 F.O.B. prices increased $1.93 per ton while hourly earnings increased $.66 per hour. Since 1948 (with the ex¬ception of 1957) F.O.B. prices have declined $.45/ton, while hourly earnings have increased $1.23 per hour. Basically the maintenance men possibly represent the highest increment rate in the overall hourly earning.

Jan 1, 1963

By Ande&apos, Bengt n

The first Model 480 SALA-HGMS R carousel high gradient magnetic separator was recently manufactured (Figure 1). The carousel's design was based upon the high gradient magnetic separation technology developed and owned by Sala Magnetics Incorporated, Cambridge, Massachusetts. After a short (approximately 300 hours) in-house mechanical and electrical test and break-in period, the carousel was ready for a long term demonstration test. This paper describes the demonstration plant and operational performance of the Model 480 HGMS treating a low grade iron ore tailings. A location convenient to Sala International's main office in Sala, Sweden was desirable because Sala engineers and technicians were to operate the demonstration plant. The Strassa iron ore mine in central Sweden was chosen because it fit most of the criteria that was important for a good demonstration site. The Strassa mine is part of the state owned Svenskt Stal AB. The mine produces about 320,000 tons of iron concentrate per year consisting of 200,000 tons of magnitite concentrate and 120,000 tons of hematite concentrate.

Jan 1, 1980

By A. K. Andersen

One of the prime examples of the versatility of the MARCONAFLO system, which is a body of technology comprising the means to handle, store, load, transport, discharge and reclaim mineral commodities in slurry form, is the direct application of this process to leaching ores. The initial approach was to provide a much improved materials handling system for the transport of copper ores; however, an extensive development program, inclusive of prototype and pilot plant tests, has established that a new leaching concept is possible with this system. Data are presented from the leaching operation of a 25 TPD pilot plant utilizing a copper-oxide ore, mainly chrysocolla. This pilot plant was designed to incorporate true countercurrent flow where the ore is actually in motion, as contrary to vat leaching operations, and the ore being successfully leached is fine crushed ore (3/8-inch x o), contrary to agitation leach circuits. Extractions in excess of 85% of the soluble values are common with only 15 hours of retention time in the MARCONAFLO leaching system.

Jan 1, 1975

By Richard L. Sanford

The generalized rail haulage simulator described in this paper is an outgrowth of the need to expand a previously developed single level simulator to permit analysis of production problems where intermediate car storage is used. Many of the ideas of the former single level simulator, which is an integral part of an Underground Generalized Materials Handling Simulator (UGMHS), have been used in model development. In addition, experience gained in applying the earlier model to a variety of operating conditions has been heavily relied on. The generalized rail haulage simulation model can operate as an independent system and, as such, can be used to analyze rail haulage systems using production distributions as data input. In addition, this model is designed to replace the present rail haulage sub-assembly in the UGMHS model and the linking procedure has been integrated into the model. The flow of coal from production sections in UGMHS, for example, fill the mine cars and a condition of no empty cars at a loading station will shut down in by production systems.

Jan 1, 1974

By W. C. Hellyer

In an autogenous grinding circuit in which feed at approximately nine inches top size is reduced to a size suitable for subsequent processing, the build- up of a "critical size" fraction in the media causes problems. A "critical size" fraction has been defined as, "media too small to effect reduction by impact grinding of ore coarser than a quarter of an inch and too large to be broken by the largest size of media in the charge. 9, (1) The buildup of a "critical size" fraction reduces the capacity of the mill, increases the grinding power requirements per ton of finished product, and generally produces a finer grind than is desired. It is general practice to overcome this problem by the addition of large diameter steel balls to the grinding charge. This has certain disadvantages, such as; (i) an increase in mill liner wear; (ii) wear on the steel balls, and; (iii) some loss in flexibility in grinding circuit operations resulting from difficulties in removing the steel balls by means other than by grinding out.

Jan 1, 1970

By Kent D. Gastreich

As the number of prime surface coal mining sites diminishes with time and with the potential for increased coal demand, areas that were previously not mined because of their difficult mining conditions, marginal economics, and controversial environmental nature, will have to be considered if surface coal mining is to continue in the future. Such sites include areas near major rivers, streams, and lakes. The name most commonly given to these areas by regulatory agencies is "wetlands". The exact definition(s) to the term "wetland" will be discussed later in this paper. Most coal operators are now more than familiar with permitting requirements under the Surface Mining Control and Reclamation Act of 1977 (SMCRA). The SMCRA permanent regulatory program recognizes the fact that coal mining operations will periodically encounter streams, wetlands, etc. Although discussed in various sections of the permanent program regulations, the relationship of coal mining operations to wetlands is particularly evident in the performance standards regarding hydrologic balance and protection of fish, wildlife and related environmental values.

Jan 1, 1980

By Jaeheon Lee, Junmo Ahn, Jiajia Wu

To reduce the environmental footprint of hydrometallurgical processing of black mass from spent lithium-ion batteries (LIBs), a green leaching system based on glycine and sodium metabisulfite (Gly-SMS) was proposed. The leaching study demonstrated that the highest cobalt and lithium recoveries of 100 percent and 99.8 percent were achieved under optimal conditions. The leaching mechanism revealed that the dissolution of LiCoO2 in the Gly-SMS solution followed the shrinking core model. The apparent activation energies for cobalt and lithium were determined as 48.05 and 41.51 kJ/mol, respectively, indicating a surface chemical reaction controlling mechanism. The leachate was then processed by an acidification- precipitation technique with oxalic acid as the precipitant to remove cobalt. Glycine complexes with metal ions by zwitterionic ligand and recycles in the leaching-precipitation circuit, reducing the reagent cost. Compared to other studies, this leaching system has near-neutral operating conditions and is cost-effective, making it an economically viable alternative for treating cathode materials from spent LIBs.

Dec 1, 2024

By Douglas F. Crickmer

Pocahontas Land Corporation, a wholly-owned subsidiary of Norfolk and western Railway Company, owns a 100,000-acre block of coal lands in Martin, Johnson, Pike, Floyd and Lawrence Counties, Kentucky. These holdings were largely acquired in three major purchases between the years 1942 and 1959. The area is undeveloped and constitutes a part of the coal reserve for future mining. This block, which is principally in Martin County, lies in a triangle formed by the Levisa and Tug Forks of Big Sandy River on the sides with Dewey Dam at its base and the Town of Louisa at the apex. The topography'is typical of eastern Kentucky and consists of steep hills rising from 500 to 800 feet above creek level. There is little level ground in the area. As a matter of fact, some roads are on the creek bottoms with what little bottom land is available in the hollows being utilized for small-scale farming. The steep hills are marked by three separate massive sandstone formations which form cliffs ranging from 40 to 100 feet in height.

Jan 1, 1964

By Claude M. Moreland

It is common practice when thermally drying coal from wet coal preparation facilities that the coarse +0.5mm fractions and fine fractions (-0.5mm) are combined and fed to a thermal dryer. There are very good reasons for this concept. The coal feed is much easier to handle in this condition for it is not as likely to stick inside the dryer or hang up in the material handling equipment, and is easier to feed and discharge. However, it is generally only the -0.5mm fines that really need to be dried. The +9.5m fraction of the cleaned coal will leave the dewatering screens, or drain and rinse screens, at an acceptable surface moisture, probably 5 or 5 ½ percent. The 9.5m x 0.5mm mesh fraction can be centrifuged to about 8 percent. The -0.5m fines can range from 18 to 22 percent or more, depending upon the type of equipment employed to dewater, and upon the size distribution within this size range.

Jan 1, 1982

By Henry S. Brown

At least two dozen massive sulfide deposits in the southern Appalachians have supported significant mining operations. Literally hundreds more deposits are known to exist, but are too small to be of commercial interest. Essentially all that are being, or have been, mined are those deposits that were exposed at the surface when first discovered. It is reasonable to assume that many more massive sulfide deposits, large and small, exist hidden not far beneath the surface. The ideas I am sharing with you here today are based both on my personal studies of some of the deposits and on descriptions of deposits in the literature. An attempt will be made to account for the genetic interpretation problems raised by many of these deposits posessing both "syngenetic" and "epigenetic" features. In addition, an examination will be made of the possible relationships between the massive and the not-so-massive sulfide deposits in this region. Hopefully, these observations added to those of others will eventually lead to the synthesis of a better model on which we can base exploration programs in the southern Appalachians.

Jan 1, 1976

By AMIR EHSAN KIANFAR, Moritz Ziegler, TOBIAS HARTMANN, ELISABETH CLAUSEN

Accurate positioning information is a central step in the process of increasing automation and digitalization in the mining industry. Underground mine environments are prime examples for GNSS-denied environments that pose several additional challenges for the employed indoor positioning system (IPS). This work presents an ultra-wideband (UWB)- based system specifically tailored for underground mine environments. Initially, the UWB technology is reviewed and basic concepts of IPS are explained. Both software and hardware are described in detail, including positioning algorithms, electrical circuitry and the mining-compatible enclosure. Finally, the results from field tests in an underground mine are presented and positioning performance and the influence of dilution of precision (DOP) on positioning results are empirically evaluated. The results show that the localization errors are mostly below 1 m. Individual zones of high localization errors are suspected to be caused by noise interference. Significant DOP influence due to the mining drift geometry can be confirmed. The system shows promising localization results for different mining applications, while influences negatively impacting the accuracy are presented as items for future research.

Jan 1, 2024

By Randhir S. Sehgal

After some decades of lying low and being treated as a second rate fuel, coal is back in the news. Production is rising. Predictions are for an ever expanding use, and they differ only in their rates of increase. Even the FBI is involved in trying to stop fraudulent sales of non-existent coal lands and leases to the innocent. In short, we have a nearly chaotic boom on our hands. Obviously our energy production base is in the process of undergoing a major shift, and the process will present many problems. However, there is little doubt that the industry has the basic strength and organization to be able to deal with the new issues that will arise as a result of these shifts in production and use of coal. After all, it does produce nearly 800 M tpy now, and coal is the single biggest fuel for generation of electricity. This role of coal is illustrated in the table below, which shows the coal equivalent quantities of various fuels used in the production of electricity.

Jan 1, 1980

By Charles LeMoyne

The Cable belt Company has been building single flight conveyors for a number of years. The simple design concepts of this type conveyor, introduced over thirty years ago, when distances of one to two miles were considered major advances in technology, remain relatively unchanged. Conveyors that are 6 to 20 miles (9.0 to 32 kilometers) long are being built and are presently in operation through- out the free world. The Cable Belt conveyor is not conventional in its construction. Cable welt differs from conventional troughed idler conveyors in that the driving medium and carrying medium are separated. Motion is provided by two endless steel cables running the length of the conveyor. The cables are driven by a single drive unit incorporating a differential gear which insures identical cable linear speeds and equal tension in both cables at all times. The belting is located and supported by "V" shaped shoeforms moulded to the belt which form a wedging action. The friction between the belting and rope is sufficient to prevent slippage (See figure 01).

Jan 1, 1983

By Keith G. Wallace

Coal mine ventilation systems are often subject to high leakage rates. As a result, changes in airflow resistance will strongly affect the efficiency with which air is delivered to the working place. One major source of airflow resistance is the line brattice used to direct air from the last open crosscut to the working face. Because it is a great distance from the fan, the resistance of the line brattice can result in more overall leakage than an equivalent resistance closer to the fan. Substituting auxiliary fans for brattice eliminates this source of resistance, with improvements in system efficiency and cost. Also, in some mines, the leakage that leads to spontaneous combustion can be reduced. The benefits obtained by several different brattice and fan substitutions have been studied by Mine Ventilation Services, Inc., under contract to the Bureau of Mines. Changes in main fan duty were compared with additional costs associated with auxiliary fans. Results indicate that in some circumstances, considerable leakage reductions and cost savings are possible.

Jan 1, 1986

By C. K. Jankousky

The midwestern area referred to is the Illinois basin. The coals presently worked are mainly the No. 5 and No. 6 coal seams which vary in thickness from five to eleven feet. Present average of the more important No. 6 id about nine feet. The coal can vary considerably in toughness within the same mine with some coal perhaps rashing very easily and other coal being extremely difficult to cut. Top is generally well laminated shales with some fortunate areas having limestone roof. There are local areas with troublesome top of poorly laminated shales, shale with slickensides and shale intermingled with small partings and traces of coal. The bottoms are generally one to three feet of clay which softens readily on exposure to moisture. The mines are dry although some water is released and collects from rapid penetration of the seam by continuous miners. However, there are locally wet areas. Most of this material refers to mines of the Freeman Coal Mining Corporation. The mining operations written about are underground mines in southern and central Illinois.

Jan 1, 1962

By I. S. Parrish

Locating and defining an ore body with minerals or metals that can be recovered at a profit is the objective of minerals exploration. Direct exploration involves examining and sampling rocks either in outcrop, underground exposure, drill core, or cuttings. Indirect exploration infers the measurement of some physical, chemical, or biological factor that reflects the possible presence of the metal or mineral of interest, or a structure that may act to collect, concentrate, or otherwise favor the presence of the desired commodity. Included here are all forms of geophysical, geochemical, or geotech-nical prospecting. In recent years, indirect exploration has given rise to an impressive number of specialists and a variety of techniques. Less impressive is the success rate or productivity of the modern explorationist. Exploration Productivity Losing Ground Judging from the low number of mine openings or mine discoveries in recent years, the exploration industry is not as productive as it once was. Many will take umbrage at this judgment, but a review of the literature will support this statement. In Canada, from 1951 through 1960, there was an average of 5.6 discoveries a year. From 1961 through 1976 there were only four a year. This nearly 30% reduction occurred despite a massive increase in exploration funding. From 1950 to 1955, the Canadian mining industry spent $5 million (1975 dollars) for each minable deposit found. During the period 1970 to 1975, the cost was $25 million for each one found. The industry was spending five times as much and finding 30% less than a generation earlier. This is not indicative of a productive endeavor. The loss in productivity is even more apparent to explorationists who wander the western US, and are awed by the thoroughness and discovery rate of those early prospectors who explored from 1850-1920. The "old-timers" missed very little. They used pans and crude chemical tests in place of plasma or X-ray fluorescent assay techniques. But, they found ore bodies that led to mines. Today, the best prospecting areas are pockmarked by the hand dug pits, trenches, and shafts left by our predecessors. The success or productivity of the old-timers may be attributed to any or all of several factors. Granted, they were looking at virgin ground and at deposits that in many places were exposed. The factor most critical is, however, that they employed direct exploration methods. They walked over areas of interest, traversed swamps and mountains, and followed "colors" in stream gravels to their source. They also chipped rocks, dug pits, trenched along structures, and followed the "leads." Many of today's explorationists, on the other hand, adopt a more sophisticated approach. A geologic model is conjured up so the exploration team "knows" models, but the model should be applied at a later stage in the exploration effort. J. D. Ridge has written an excellent article on the role and timing of models. Geologists should collect and assemble data, facts, and observations and fit these into a model and not conceive a model and seek data to prove their vision. Further, many exploration managers are adept and talented at devising exploration programs. They can program and use modern exploration techniques and tools. They can apply these and their modeling capacity to assemble a glittering array of targets. It would appear that in all too many instances, creating targets has been equated with and is considered being productive. As noted, finding ore bodies is being productive in exploration. Creating targets may or may not lead to ore bodies. As an end result, locating targets is not productive exploration. How then does one foster productivity in exploration? Some suggestions are to increase the use of direct methods, follow the methods and philosophies of old-timers, look at more rocks, do more field work, use foot traverses, and do more drilling. It may be argued that this is what the old-timers have done and we would then be hoping to find

Jan 11, 1983

By James J. Fallon

I'm glad this meeting is being held in New York. First, because the city is close to my home in New Jersey, only 35 minutes from Times Square ..... if I were to come to Times Square between two and three in the morning. Otherwise it takes two hours. But even more important is the fact that all of you good people from around the country and around the world will enjoy the unique experience of that warm friendly atmosphere in the greater metropolitan area, something that you won't see any place else on the face of the earth. Seriously, the greater metropolitan area has been a large part of my industrial, cultural and spiritual experience. There are many aspects of it which I find disagreeable but on net I would rather live in this area, at least for the time being, than any other area of the United States. As a consultant I find contact with financial institutions, corporate headquarters, information sources and a great many production and research facilities a valuable asset to my activity.

Jan 1, 1985

By Akihiro Higashide, Roy H. Patten

The DOT Tunneling method combines two conventional earth pressure balance shield machines in an overlapping cylindrical arrangement. The method allows two tunnels to be driven simultaneously with mini¬mum cross sectional area. Two full size trials, one configured horizontally and one vertically stacked, were successfully completed employing the DOT method. The method was then utilized for the new transportation system. The goggle-shaped DOT machine, 9.36 m high by 15.86 m wide, is the largest earth pressure balance shield machine in the world. This paper includes a general description of the DOT tunneling method as well as a history of its development.

Jan 1, 1995