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By Craig J. Brown

Despite its great potential utility, ion exchange has only achieved limited application in hydrometallurgy. To a significant extent this is due to the limitations of conventional ion exchange process design as well as the properties of the ion exchange resins themselves. Over the past decade several new ion exchange resins have been introduced with properties that make them potentially very useful for various hydrometallurgical separations. In addition, a novel ion exchange process called Reciprocating Flow Ion Exchange or Recoflo, which has been employed in the metal finishing industry for the last dozen or so years for chemical recovery and effluent treatment, has been shown to offer a number of unique and significant advantages over conventional I.X. technology.

Jan 1, 1984

By M. Galetakis

The difficulties that rise during the evaluation of multiple-layer lignite deposits come from the deposit structure (alternating lignite layers with intercalated material of varying thickness), as well as from the limitations of the applied selective mining. Thin layers of lignite and interbedded waste layers are grouped under specified assumptions regarding thickness and ash content, to form the exploitable blocks. However, in practice the decision for excavating a block is made under subjective constraints of different importance or by using uncertain data. Advances in Fuzzy Inference Systems (FIS) have provided a new approach to the evaluation of multiple-layer lignite deposits. FIS have the ability to handle imprecise or incomplete or linguistically ambiguous information and to incorporate them into decision-making processes. In the developed FIS (Mamdani type) new linguistic variables, concerning with working conditions, operators? experience and production were involved. The FIS was used for the estimation of quality characteristics and reserves of the exploitable lignite produced from Southern Field mine, Ptolemais (Greece).

Jan 1, 2005

By K. W. Vincent

This paper, deals with the beneficiation of a low grade Western phosphate to ore. More specifically it summarizes the results of a study made to optimize a scrubbing step in the process, and to provide firmer data for use in plant design. The deposit is situated about 30 miles northeast of Pocatello, Idaho, in the Fort Hall Indian Reservation. It is a bedded deposit and throughout most o the orebody includes three contiguous layers of phosphatic material which differ in P205 content. The J. R. Simplot Company, as operator for a Simplot-FMC joint venture, mines the ore selectively by open pit methods The lower bed containing a nominal 30% P205 is shipped to the Simplot Company fertilizer complex near Pocatello; the middle layer averaging about 24% P205 supplies the FMC elemental phosphorus plant also near Pocatello, The top layer averaging around 16% P205 and designated as mill grade shale is stockpiled for future beneficiation. This paper is concerned with some aspects of the processing of this low grade shale.

Jan 1, 1965

By Kevin Hegerle

The Henderson Mill has operated over a wide range of production rates, feed grades, manpower levels and recovery targets since start-up in 1976. Henderson Mill personnel, both management and hourly, have successfully responded to these changes by not only maintaining unit costs, but by actually decreasing unit costs. Methods of cost reduction have included conventional austerity programs, innovative technological improvements and creative work schedules. This paper addresses both maintenance and operating cost reductions and efficiency improvements.

Jan 1, 1986

By J. R. Nawrot

Reclamation of potentially acid producing coal processing waste requires a 4-foot cover, and/or treatment to allow vegetation establishment. If not planned properly, soil covering alone does not prevent refuse acidification or formation of acid seeps. Adequate neutralization enhancement prior to soil covering can maintain an alkaline environment in the soil refuse interface and prevent acidification. Direct vegetation establishment using only limestone amendment (without soil cover) can successfully reclaim aged and weathered fine (Blurry) and coarse (gob) refuse if adequate neutralization treatment is provided for the oxidized surface zone. Acid seeps, representing an "after-the-fact" verification of an imbalance of acid-base equilibrium may also be corrected using upslope alkaline recharge techniques. Concentrated alkaline recharge pools have been constructed above previously soil covered acid gob at the Peabody Will Scarlet Mine to abate acid seeps. Preliminary monitoring results (1989-1992) from a concentrated alkaline recharge pool demonstration project in the Pit 4 area of the Will Scarlet Mine have documented a 50 to 80 percent reduction in acidity in the principal recharge pool groundwater zone. A 22% reduction in acidity has occurred in the primary seeps located downslope from the alkaline recharge pools. The initial improvements in water quality are seen as a positive indication that groundwater acidity will decrease further and amelioration of the acid seep will continue.

Jan 1, 1993

By Takashi Goto

In 1968 three historical rockbursts had occurred at Bibai Coal Mine in Hokkaido. At the time they had been observed by several seismic observatories as natural earthquakes away more than 100km from Bibai City. These facts taught us that the occuerrence of failure yielded in underground opening that was accompanied with seismic wave could be observed by seismometer on the surface. After two years from this desaster, the study concerning to microseismic events generated from underground mining panels has been begun by researchers with heart-throb.

Jan 1, 1982

By H. Sevim

The utilization of high sulfur Illinois coal by utility plants has been decreasing since the enactment of 1990 Clean Coal Air Act Amendment. Illinois coal producers can make their coal saleable by offering the choice of taking the combustion by-products from the utility plants and placing them in the abandoned sections of their mines. To be competitive, however, coal producers need to select an environmentally acceptable transportation-handling-placement system through which the cost-per-ton of by-product disposed can be minimized. In this paper, a few such systems are presented. The favorable operating range of each system is determined in terms of distance and tonnage. A case study is given whereby cost analysis is conducted for an underground coal mine receiving by-products from two Illinois utility plants.

Jan 1, 1997

By S. P. Brown, J. E. Worthington

Increasingly, exploration geology seems to be growing into a practice overly separated from production geology, yet the eventual purpose of exploration is a producing mine. To help in the search for new deposits, exploration "lessons" will be drawn from the papers given at the Fall AIME Applied Geology Symposium. In addition, examples will be re-emphasized to show how early observation of matters now routine to mine work (for example, hydrology, rock mechanics, oxidation state) can help increase the effectiveness of exploration.

Jan 1, 1992

By J. C. Purcupile

In this time of increased coal demand, a faster and safer method for roof support is needed. This report outlines the preparation and testing of a machine which we feel will help answer this need. The results of the tests are encouraging, and indicate that further exploration of the method should be continued.

Jan 1, 1975

By James G. Tilton

Throughout the world, sedimentary basins are exploited for many different minerals. Frequently, the extractive methods conflict with one another. A case in point is the proximity of oil and gas operations and the mining of coal. Generally, the interference between the two industries lies in the fact that the reserves over- lie or underlie one another. Mining of coal generally is developed on a rectangular pattern in a horizontal mode while oil and gas drilling is developed on a radial pattern in a vertical mode. Coal mining has exhausted vast acreages in various basins with many of those basins being drilled for oil and gas. Those existing wells create problems by requiring the unrecoverable coal pillars to support the well bore, or to make special provisions in order to mine through an existing well. The system works ... more or less; but there are little or no provisions made for additional drilling unless the vast majority of those new wells are drilled through mined-out sections (gob) of those mines. Many states have rules and regulations governing the drilling of oil and gas wells through gob; but, some companies and some regulatory agencies or personnel have deemed such drilling as a hazard to the mining operations. This paper explores the history, technical standards, and safety aspects of drilling oil and gas wells though the gob of worked-out and active mines. It is the opinion of the author that such drilling can be conducted safely while eliminating the re- quired changes in mine projections and the loss of recoverable coal in the form of well pillars.

Jan 1, 1997

By J. L. Carr, A. K. Smith, C. C. Jobes, G. T. Homce

"Underground continuous mining machines pose a difficult safety challenge since their operators generally work in close proximity to these machines in very restricted spaces. Intelligent software for use with magnetic proximity detection systems has been shown to accurately locate workers around mining machinery in real time. Calibrating these systems requires the manipulation of a lot of data to determine the calibration constants. Researchers have developed software to analyze, convert, and visualize data acquired during this calibration process to more accurately model magnetic fields and their interaction with the environment. This paper details the background, development, and operation of the resulting application software focusing on the utility of the graphical user interface to visualize the magnetic field calibration data. The refined data developed by this process can then be utilized by the proximity detection system to more accurately identify the location of miners working in an underground mining environment. INTRODUCTION Roughly half of the electricity consumed in the United States is produced with coal, and roughly one-third of all US coal production comes from underground mines [1]. Over the last century underground mining health and safety has seen a continuous and dramatic improvement. However, machine-related injuries and fatalities continue to be a major safety concern [2]. Every year, hundreds of miners are severely injured while operating underground mining equipment, and 39 miners have been killed in striking/pinning accidents involving continuous mining machines (CMMs) since 1984. CMMs, such as the one shown in Figure 1, are large mobile machines that are used to mechanically cut coal in an underground mine. These machines weigh approximately 40 to 50 tons, have hydraulically articulated appendages, and are capable of moving at speeds up to six feet per second [3]. Modern CMMs are remote-controlled, yet the operator and other miners are often in close proximity to the machine. Recent research by the National Institute for Occupational Safety and Health (NIOSH) reveals that the locations workers take relative to the CMM are usually influenced by visibility requirements and safety concerns [4]. The Mine Safety and Health Administration (MSHA) estimates that at least 28 fatalities involving CMMs since October of 1984 may have been prevented with proximity detection technology [5]. MSHA further estimates that proximity detection could prevent 20% of all deaths throughout the industry [6]."

Jan 1, 2016

By P. G. Kovalchik

Recent research conducted by NIOSH, Pittsburgh Research Laboratory showed that electrical current levels permitted under present regulations may not limit cable temperatures to less than 90°C in reeled trailing cables. Reeled cables, tightly wrapped with many turns, all carrying current in an enclosed space, can become overheated due to poor heat transfer. This overheating can cause the cable insulation to soften and become easily damaged. The damaged insulation reduces the life of the cable and can lead to shock, electrocution, and mine fires. This paper describes a method of measuring the conductor temperature of mine trailing cables during normal operation. The temperature is measured using a 50/125 micrometer Graded Index Multimode Optical Fiber located in the center of the metallic conductors. Distributed temperature measurements are made using an Optical Time Domain Reflectometer (OTDR). This system is capable of measuring temperature with an accuracy of plus or minus one degree centigrade over a length of 4 km at 1-m intervals. With this unique way of measuring temperature, tests can be conducted simulating actual mine conditions and provide important data to allow MSHA's Approval and Certification Center to develop approval criteria for cyclically rated reeled machines.

Jan 1, 1998

By D. L. Lampshire

Biological leaching using native heterotrophic bacteria was studied by the U.S. Bureau of Mines as a means of extracting manganese from a domestic low-grade wad ore. Column heap leaching simulation techniques were employed using molasses as the nutrient source for the bacteria. These column studies were designed to investigate the effects of molasses medium flow rate, concentration, and replacement interval on the extent and rate of manganese extraction. .Results showed that flow rates between 0.41 and 8.1 L/min/m2 had little impact on manganese extraction. The total amount of molasses used did have a direct effect on the extent and rate of manganese extraction. Manganese extractions over 90-pct were obtained in 12 weeks of bioleaching with 2-week medium replacement cycles.

Jan 1, 1993

By S. Upadhyay, A. M. Afrapoli

"Fluctuation in market price of mineral products has enforced mining companies to cut down their operating costs. One useful way of reducing operating costs in mining operations is to make optimal operational decisions, incorporating efficient mining fleet management systems (FMS). Over the last 50 years, several types of FMS have been developed and introduced in the mining systems around the world. However, there are two major shortcomings in existing systems. Firstly, none of the existing systems consider effects of the short-term plan on dynamic truck assignment. Secondly, most of the existing FMSs make decisions in a way that optimize a specific objective while ignoring others. Herein, we propose a multi stage and multi objective FMS that deals with aforementioned shortcomings of the currently available systems. The developed FMS, in its upper stage, links semi-dynamic operational decision making process to the short-term production plan by simultaneously assigning shovels to mining faces and allocating trucks to the shovels by implementing its first multi objective decision making model. Then in its second stage, in a real time dynamic decision making process, it assigns trucks to shovels and corresponding destinations by optimizing its second multi objective decision making model. The developed fleet management system has been verified using an Iron ore case study and the results are presented in this paper. INTRODUCTION Open pit mining method is the most common method to mine mineral from the earth. Based on Wetherelt and van der Wielen (2011) there exist 2500 open pit metal mines that are categorized as industrial scale mines. Over all of those, the amount of material handled using truck and shovel material handling system is more than the amount handled by all other systems together (Humphrey & Wagner, 2011).It has been proven by several studies that more than 50 percent of operating cost in a truck and shovel based open pit mining operation is accounted for material handling (Moradi Afrapoli & Askari-Nasab, 2017, Alarie & Gamache, 2002, Ahangaran et al., 2012). Thus, introducing even 1 to 2 percent cut in its material handling cost saves huge amount of money for the stakeholders. Over the last 50 years, two major areas have been identified to cut this cost. On one hand mining industries have been implementing equipment with higher production capacities, and on the other hand, researchers have been developing operations research techniques to make dynamic decisions as close to optimal as possible to deduct operational costs in truck and shovel based mining operations."

Jan 1, 2018

By R. E. Le Messurier

GENERAL DESCRIPTION The mines are located at Broken Hill in the western part of New South Wales, Australia, 930 km west¬northwest of Sydney. Mining Methods Where pillars must be left between stopes, extraction of a block of ore between two or more levels is carried out in stages: 1) Stopes are mined overhand by horizontal cut¬and-fill stoping, or by long-hole stoping. The various methods of horizontal cut-and-fill stoping used are desig¬nated as: -Loader cut-and-fill stoping with horizontal blast¬holes and diesel load-haul-dump (LHD) units. -Open stoping with horizontal blastholes and com¬pressed air or electric scrapers, or with diesel or electric LHD units. Square-set timber stoping, where ground condition precludes open stoping. The backs are sup¬ported with timber square sets. Pattern rockbolting of the backs may be used as an intermediate stage between open stoping and square-set stoping. 2) Vertical pillars are mined by undercut-and-fill stoping or by vertical crater retreat stoping. 3) Where a horizontal pillar has been formed below the level above the primary stope, this level pillar, usually 6.1 to 8.2 m in depth, may be mined by over¬hand square-set stoping or by undercut-and-fill. Long-hole stoping is used at the Zinc Corp. (ZC) and New Broken Hill Consolidated (NBHC) to mine parts of the zinc-rich A and B lodes. Drilling is carried out from drill drives and, in some cases, sills. Hole sizes used are 165 mm (61/2 in.), 110 mm (4'h in.), and 65 mm (21/2 in.) nominal diam with hole lengths being limited to 50, 30, and 20 m respectively. Ammonium nitrate-fuel oil (ANFO) and water gel explosives are used. Broken ore is loaded from drawpoints at the bottom of the stope using rubber-tired diesel-driven LHD units which deliver ore to an orepass. Annual production at Zinc Corp. and NBHC accord¬ing to mining method is given in Table 1. At Zinc Corp. mining is being carried out at depths varying between 200 and 832 m. At NBHC it ranges from 528 to 915 m below the surface. The average travel time to the stope is 30 to 45 min. GENERAL ORE BODY REQUIREMENTS Size, Shape, and Dip There are six separate lodes which carry minable ore in the mines of Zinc Corp. and New Broken Hill Consolidated. The lowest of these and the main ore bodies presently being mined at Zinc Corp. are the lead lodes, consisting of a siliceous fluoritic ore body (No. 3 lens) and overlying it a calcite rhodonitic ore body (No. 2 lens). Each possesses characteristic ratios of lead, silver, and zinc, although the grade within each lens is variable, in places being as high as 30% Pb. There are also low¬grade portions which consist chiefly of poorly mineral¬ized rhodonitic material. No. 3 lens terminates within the Zinc Corp. leases, while No. 2 lens continues into the NBHC leases where it continues to provide a significant proportion of pro¬duction from the mine. Overlying the No. 2 lens are the various zinc-rich ore bodies. In ascending sequence these are lower No. 1 lens, upper No. 1 lens, A lode, and B lode. A typical assay for the small No. 1 lens group ore bodies is 8% lead, 50 g/t silver, and 20% zinc. The `A' lode is a large low-grade ore body in which the higher grade sections assay 4% lead, 30 g/t silver, and 10% zinc; larger quantities of lower grade ma¬terial also occur. B lode, the main zinc lode, typically assays 5% lead, 30 g/t silver, and 17% zinc. B lode increases in size as it extends south, and in NBHC is a major ore body, contributing about 52% of the production. All the lodes pitch south, the average pitch being 0.52 rad (30°) in the Zinc Corp. leases and rather flatter than this in the NBHC leases (see Figs. 1-3). The ground is all competent rock. Production requirements at Zinc Corp. are 900 000 t and 1 200 000 at NBHC.

Jan 1, 1982

By Erik S. Bernard

"INTRODUCTION Reinforced Concrete (RC) members such as beams and columns are usually required to include stirrups to maintain post-crack shear capacity, and some may include stirrups that act as confining steel to maintain structural integrity during a seismic event (eg. NZS3101, ACI 318). To achieve seismic resistance, the spacing between stirrups is usually required to be much closer than is ordinarily prescribed for non-seismically resistant structures. Each stirrup must also fully enclose the longitudinal reinforcement with long end-hooks to ensure that the contained concrete is sufficiently restrained during reverse-cycle loading and the reinforcing bars are confined to prevent buckling. The close spacing between stirrups can lead to congestion of reinforcement within members, and can also be expensive to construct due to the labor-intensive nature of steel fixing. A possible alternative to closely-spaced stirrups is the use of fibers to provide restraint and confinement during a seismic event, although this is not yet recognized in codes. Previous experimental research (Jiuru et al, 1992; Filiatrault et al, 1995; Bayasi and Gebman, 2002; Billington and Yoon, 2004) has demonstrated that steel fibers are relatively effective in this application, but suffer the problem that their stiffness can make them difficult to consolidate within an already tight reinforcement cage, especially if they are relatively long (>40 mm). Moreover, steel fiber reinforced concrete (SFRC) is subject to embrittlement with the passage of time, leading to a steady loss of ductility beyond crack widths of 1-2 mm (Banthia and Trottier, 1994; Bernard and Hanke, 2002; Bernard, 2014; Bjontegaard et al, 2014; Bernard, 2015). Since cracks during seismic events are generally much larger than this, embrittlement may present a challenge to the long-term efficacy of SFRC during seismic events. An alternative to steel fibers for enhancement of seismic resistance is the use of macro-synthetic fibers. This type of fiber usually offers the advantage of being flexible so that consolidation is easier between reinforcing bars. They also offer superior durability compared to steel fibers and can reduce flexural crack widths (Bernard, 2016). Several recent small-scale investigations (Ma et al, 2012; Carnovale, 2012; Osorio et al, 2014) have indicated that macro-synthetic fibers can produce meaningful improvements in seismic resistance if used in combination with conventional steel reinforcing bars. The present investigation has extended research in this field by examining whether embossed macro-synthetic fibers can be used to increase the spacing between stirrups while maintaining seismic resistance."

Jan 1, 2016

By T. J. Fenner

Surface and underground mining operations are often hindered by unknown tunnels and stopes and the precise locations of adjacent workings. Mine safety and planning are adversely affected especially in previously undermined areas where historical records are incomplete or non-existent. The results of several Ground Penetrating Radar (GPR) studies for the detection of known mine tunnels in underground coal; salt, and gold mines are presented. A case study to locate unknown, abandoned mine workings at a surface gold mine successfully located all workings to a depth of 11 meters.

Jan 1, 1992

By D. G. Chedgy

Environmental improvement efforts are focusing with increasing intensity on pollutants resulting from combustion. The high cost of removing these pollutants at the power station is well documented. Physical coal cleaning has always been and should remain the most economic method of reducing sulfur oxide emission from coal combustion. It is critical in the selection of preparation plant circuitry to consider capital and operating costs, as well as the level of sulfur reduction. This paper describes the technical criteria which must be used for efficient process selection and summarizes the cleaning systems available or in development.

Jan 1, 1990

By Brig M. Moudgil

It was reported earlier that francolite and dolomite from the South Florida deposits cannot be selectively floated using conventional conditioning with sodium oleate as the collector. However, dolomite could be separated from francolite if the minerals were first conditioned at pH 10 followed by reconditioning at a lower pH. An optimum separation was achieved at a reconditioning pH below 4.5. Reconditioning pH and collector concentration were determined to exert a major influence on the selectivity. Flotation, adsorption and transmission infrared spectroscopic results are presented to elucidate the mechanisms underlying the observed selectivity.

Jan 1, 1984

By Thomas E. Finch

Coal produced from surface mines in the Western United States is becoming a more important part of this nation's economy as other types of fuels become scarce. This paper reports the investigation of alternative methods of handling the parting between two coal seams. The results of this investigation are presented as the engineering-economic aspects of alternative parting handling methods involving stowing or back filling techniques. The coal and parting characteristics were selected as being representative of those under consideration or actively mined in the West. The basic philosophy of evaluation is to establish a mine-within-a-mine where equipment selected for minimal capital investment can remove the parting and second seam nearly independent of the ongoing, present production. With proper consideration of design, this parting-coal removal is evaluated as a second operation within the first and has its own profitability measure. The Fort Union Area of Montana, Wyoming, and the Dakotas contains large reserves of low sulfur sub-bituminous coal. In many locations, several coal seams are close to the surface and are separated by relatively thin layers of parting. The removal of overburden and the mining of the upper seam is accomplished effectively with conventional mining methods and equipment. Mining a second seam of coal and handling the parting in accord with economic and environmental controls presents a number of problems. Typically, mining companies have adapted the conventional strip mining techniques used in the East. However, the extreme thickness of the western coal seams offers alternative mining method possibilities for parting and second seam removal.

Jan 1, 1976