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By J. P. Kennedy

Process data managers or historians are recognized as essential for reengineering projects in industrial plants. With increasing automatic data collection, the knowledge of how to use these data profitably grows as well. This paper is a summary of the data historian and its components plus examples of benefits including environmental reporting, performance monitoring, and exception reporting to management.

Jan 1, 1994

By André Vervoort

After the systematic closure of Europe’s coalfields in the late twentieth century, the emphasis is now clearly on industry’s environmental legacy. One aspect of the latter is the longterm surface movement above abandoned coal mines. The analysis of satellite data shows that the subsidence lasts longer than generally assumed. However, a few years after the flooding of the abandoned underground coal mines, a new phenomenon was observed, i.e., the direction of the surface movement was reversed. The phase of upsidence has already lasted for several decades, and only future measurements will tell how long it continues. A key conclusion is that the regions with maximum subsidence do not necessarily correspond to the greatest upsidence. In other words, buildings and infrastructure are subjected to a different loading from this upsidence than during the subsidence phase. The longterm surface movements have an impact on vulnerable structures in the densely populated regions of the former deep coal mining areas in Europe. These movements create additional damage. This new knowledge is also relevant for mines that are still in operation or future mines that are planned.

Feb 1, 2024

By H. Sis, D. Dahlin, S. Chander, C. Summers

Bench-scale selective-flocculation tests were conducted on samples of Florida phosphate and Western phosphate process tailings to recover upgraded phosphate concentrates. After physical and mineralogical characterization, the slurry samples were treated with a broad suite of flocculants with a range of molecular weights and anionic functional groups. Parameters investigated included pH, dispersant and flocculant types, and dose; conditioning parameters and settling times were, for the most part, held constant. Where selectivity was achieved, phosphate minerals remained dispersed, whereas silicate minerals flocculated and settled. Single-stage tests using reagents with low to medium anionic characteristics produced upgraded phosphate concentrates at moderately elevated pH. Two- stage site-blocking tests, in which low-molecular-weight flocculants were used as site-blocking agents, gave improved results.

Jan 1, 2002

By T. P. Meloy

Improvement of grade and recovery requires the use of optimum processing circuits. Critical to an optimum circuit is the set point for separation. With the introduction of the concept of circuit analysis (Meloy, 1982), it became possible to determine optimum circuits for a given task. No analysis, however, has yet been made as to the grade requirements of the larger circuits. Williams and Meloy (1982), reviewed the literature and concluded that, within the operating range, most unit operations involved in particle separation behave linearly. For the purposes of this analysis, linearity will be assumed. Grade, G, is defined as the weight of the coal mineral, C, that appears in the product, divided by the weight of the coal mineral plus the weight of the gangue mineral or waste mineral, Q, which appear in the product.

Jan 1, 1982

By E. Suoninen, K. Laajalehto, L. Kartio

Efficient separation of pyrite from other sulfides is of great importance for the metallurgical performance of flotation processes. In this work Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS) were used to study the surface chemistry of pyrite in depression, activation and xanthate adsorption under conditions of controlled potential. Modifications of pyrite surfaces after treatment with depressants (lime, sulfur dioxide, sodium cyanide) and after activation with metal ions (Cu, Pb) were studied. The principal adsorption product identified on pyrite was dixanthogen whose formation started at about +0.15 V and +0.25 V (vs, SHE) in ethyl and amyl xanthate solutions, respectively. Copper xanthate was formed on copper(II) activated pyrite. Activation mechanism of pyrite by copper(II) salts is likely to be electrochemical where copper occurs as copper(I) on the surface of pyrite. Effective depression is achieved by sulfur dioxide and sodium cyanide. Depression at high pH is due to formation of iron(III) hydroxides. Calcium ions do not affect the electrochemistry but adsorb on pyrite and reduce the surface sites for dixanthogen adsorption.

Jan 1, 1995

By Kenneth R. Miller

ThunderBasin Coal Co. has two mines located in the southern portion of Wyoming's Powder River Basin - the Black Thunder Mine and the Coal Creek Mine. Both are located 60 to 90 kin (37 to 55 miles) southeast of Gillette. The mines are principally located on federal coal leases acquired in the late-1960s. Development plans for the Black Thunder Mine focused on dragline stripping. Environmental considerations, however, made truck-shovel stripping the method of choice when the mine opened in 1976. In 1981, the Coal Creek Mine opened as the first dragline mine in the Gillette area of the Powder River Basin. The regional terrain is flat-lyimg with occasional clinker-capped hills. The mines are located on the Wasatch and Fort Union Formation contact. The coals are Paleocene in age. The deposits are structurally simple, dipping gently to the west. The seams are thick and are classified as sub-bituminous-C. The Black Thunder Mine, with its 21-m (70-ft) 'hick seam, is strategically located in the center of the highest heat value mining area of the southern Powder River Basin.

Jan 1, 1993

By Joseph M. Denk, Gary J. Wirth

This paper summarizes a three phase face ventilation study which was conducted from September 1989 through March 1990 to determine face area methane liberation patterns on two extended longwall sections. The coal seam being mined was considered gassy and the mine liberated an average of 14.4 million cubic feet per day (cfd) or 0.41 million cubic meters per day (cmd) of methane through the mine fans. The mine also used an extensive underground degasification program to recover up to 13.4 million cfd (0.38 million cmd) of methane. Data was collected while the longwall sections were mining from the beginning, middle and end of panel extraction to determine the relationship between the methane liberation and extent of longwall retreat. As expected, methane concentrations did increase from the headgate (intake) to the tailgate (return) side of the longwall face and peak concentrations were detected above the shearer as it passed a methanometer location during mining. There were significant differences in the methane liberations due to the location of the active face within the longwall panel. Results from this study could be used to determine a minimum design face air quantity for an extended longwall section operating under similar conditions.

Jan 1, 1991

By Richard Hogg, Erol Kaya, Jan M. Mutmansky

Characterization of the size, shape, chemical composition, and mineralogical content of mine airborne dusts generally requires a larger mass of dust particles than is typically collected using traditional sampling devices. In this paper, the general design of a passive dust collector is described and the field results are presented. The collector was constructed of galvanized sheet metal duct with a resin-coated honeycomb to provide an elutriation-type system for particle collection. Several versions of the collector were used in the field portions of the research. The dust samples collected from underground coal mines were found to possess angular particle shapes, relatively consistent size distributions, and elemental compositions that showed relatively little variation, at least for the more prevalent elements. In addition, the distributions of particles sizes obtained from the passive dust collector appear to be similar to those of samples collected at the same time in a conventional personal sampler except that the passive device seems to collect a larger quantity of coarse, non- respirable particles. Conclusions on the suitability of this dust collector for collecting characterization samples are presented. In addition, the potential for using such a dust collection system for supplying dusts for biomedical research is discussed.

Jan 1, 1993

By Herbert Pöllmann

The mineralogical and chemical compositions of various waste materials undergo different reactions when treated thermally The heavy metal contents can be bound to stable phases. These minerals are called reservoir minerals. The main property of these minerals is the stability in their geochemical surrounding containing the heavy metal cations and anions. Examples for these minerals are apatites, spinels, garnets, perovskites and also water containing minerals like ettringites, metal-metal-hydroxi salts, jarosites and zeolites. When the chemical compositions of different wastes are mixed according to the compositions of the new formed minerals, a probable reuse of these wastes can be obtained. The use of waste incineration ashes for the production of cementitious binders and the use of flue gas desulfurization products for cement additives are shown. Also the transformation of highly contaminated materials into stable reservoir mineral assemblages are shown including the study of stabilization and immobilization techniques.

Jan 1, 1998

By P. J. Kientzler, Y. C. Lo

The current study is concerned with the analysis and attempt at simulating the product size distributions obtained from a vibrating ultrasonic device. Systematic experiments of comminution were performed with natural sizes as well as monosizes in order to understand the breakage behavior of the device. A precise analysis of the device's breakage performance in the case of fine grinding of alumina samples will be presented. Initial steps to model the breakage events using a detailed mathematical algorithm will be discussed.

Jan 1, 1992

By E. S. Smith, Sunirmal Banerjee

INTRODUCTION Social awareness of the detrimental impact of man-made wastes on our environment has grown considerably during the last two decades. Increased public and institutional concerns have resulted in the implementation of a wide variety of regulatory controls of disposal of wastes. These regulations have often reflected significant conservatism in expecting guaranteed elimination of pollution risks. This sort of expectation assumed a state of knowledge which was not readily available to the major producers of wastes. The mining industry, in particular, has been affected by such regulations in terms of excessive costs and loss of benefit. As a result, investigations are in progress (1) to generate newer methods for satisfactory stabilization of mine and mill wastes and (2) to apply the available technology to achieve the standards set by the regulatory agencies at reasonable costs. This paper presents a conceptual scheme for stabilization of mill wastes by suitable management of operations and accelerated consolidation of tailings slurries. The main discussion in this paper is aimed at the ability of the proposed scheme to address the major considerations in effective disposal. Comparison in both cost and effectiveness are also made between the proposed scheme and various other currently used disposal concepts. MAJOR CONSIDERATIONS IN EFFECTIVE DISPOSAL The primary objective of an effective tailings disposal scheme is to provide containment of the contaminants in such a manner that the undesirable impact of the wastes on the three basic elements of our environment--land, air, and water-would be minimal. Bearing the above objective in mind, one may justifiably list the major considerations in the choice of the disposal scheme in terms of its effects on land, air, and water (Bromwell, 1976) as follows: Effects on Land (1) whether the scheme makes optimal use of land.

Jan 1, 1980

By Felicia F. Peng, Wenguang Wang

The purpose of this research work is to predict the dust concentration distributions of different particle sizes on longwall faces. This Is necessary because the dust sources must be identified before dust control techniques can be recommended and applied correctly. The dust concentration data at longwall faces were determined by using Real-time aerosol monitors (RAM-1) and gravimetric monitors. However, these field data cannot explain the nature or the mechanisms of dust flow phenomenon on longwall face. Therefore, a mathematical model Is developed taking Into account the characteristics of airflow, the natures of dust generation and particles, the mechanisms of dust transport and deposition as well as the multiple dust sources on the longwall faces. In this paper, the identification of respirable dust sources on the longwall faces are determined. The dust particle size distributions In various longwall faces are analyzed and classified. The comparison analyses of field data and model predictions are presented. Specifically, the general trends of dust concentration on the longwall faces obtained at different positions and at various conditions are discussed.

Jan 1, 1991

By H. Soto, G. Barbery

The effect of particle size on the flotation of coarse particles is analyzed. It is concluded that turbulence and the presence of the froth layer are detrimental to the recovery of coarse particles during conventional flotation. A counter-current column cell is proposed to avoid these two factors. In this column, a net upwards flow of water is prevalent, such that no froth is allowed to form on the top. Also, the levitation of heavy bubble-particle aggregates is helped by the ascending water current. Preliminary work at laboratory level with kilogram-size samples indicated that under similar conditions recoveries in the column were much higher than in conventional cells. Flotation results obtained with coarsely sized phosphate and quartz samples are presented. One interesting feature of this type of column is very fast flotation kinetics. Thus, a short column (only 55-cm collection zone) yielded, full recovery of floatable values.

Jan 1, 1992

By John A. DesLauriers

INTRODUCTION This paper will update the status of small sized tunnel boring machines used in both the Mining and Civil Industries. I will mention a) new developments in small size hard ground tunnel boring machines, b) review North American performance records of the Atlas Copco Mini/Midi Fullfacers, and c) compare relative costs in driving a 1200m (4000 ft) typical utility tunnel using a leased TBM versus the conventional drill and blast method. NEW DEVELOPMENTS JARVA MACHINES Of all small rock tunnel boring machines currently in use, the Jarva MARK VI and MARK VIII are receiving the most enthusiastic acceptance. These circular fullface borers using usually 15 inch single disc cutters (manufactured also by Jarva) are designed on the 'T' bracing principle. Previously, Jarva's line of tunnel boring machines, even their smallest, was designed on the 'X' or double diagonal bracing configuration with a gripper in each quadrant. In small tunnels where net room is so very important, the 'T' scheme with gripping only at the spring line nets precious room around the cutter unit for passage of men and supplies. It allows freer un-

Jan 1, 1981

By Ryan Lindmark, Guoxing Gu, Zhenghe Xu, Jacob H. Masllyah

Induction time is often referred to the time required to form a stable three-phase contact between a gas bubble and a flat or droplet surface in a liquid medium. It can be used to quantify the attachment process in aflotation system. Various techniques have been developed to measure this important parameter. Due to its importance in flotation systems and other processes, significant advances in refining the induction time measurement techniques have recently been made. This paper summarizes these recent advances and describes a novel method developed to monitor bubble attachment to a pendant bitumen drop or bitumen-coated flat surface. This visualization-based method offers a higher sensitivity and accuracy than the previously developed apparatuses in the induction time measurement. As an example, the induction time for oxygen bubble-bitumen attachment was measured at a fixed bubble size as a function of temperature in two different aqueous solutions. The results showed that higher process temperature is favorable for oxygen bubble-bitumen attachment and hence bitumen flotation. Addition of calcium to the aqueous solution slightly decreased induction time.

Jan 1, 2005

By J. F. Stenebråten, W. P. Johnson

Carbonaceous material (CM) from the Barrick Goldstrike Mines, NV, was characterized with respect to its gold sorption (preg-robbing) and gold recovery behavior. The breadth of graphite peaks measured by X-ray diffraction were used to calculate crystallite dimensions (002) of the CM. The (002) dimension was found to vary inversely with preg-robbing activity and directly with gold-recovery behavior, indicating that the degree of graphitization (maturation) experienced by the carbonaceous material is correlated with gold-loss during ore processing. The inverse correlation of preg-robbing activity was improved when percent preg-robbing was regressed against (002) crystallite size and carbon content. The (101) crystallite dimensions of all samples were calculated from laser Raman analysis, and were not found to correlate with preg-robbing behavior of the CM. BET surface area and micropore size distribution results were affected by grinding history, negating comparison of these characteristics between samples.

Jan 1, 2000

By R. A. Metz, James W. Clark, William C. Dixon, Kevin L. Wiley, Thomas R. Couzens

This paper is a description of certain geologic aspects of the Inspiration mining operation. It is not a geologic description of the Inspiration deposit nor an exposition of all the geologic work involved in the development and exploitation of the deposit. A few specific examples of the application of geology and geostatistics to the mining process are given to illustrate the progress that has been made in making the Inspiration Mine more efficient and cost effective, and a statement of the philosophy of geologic applications is offered.

Jan 1, 1992

By Sally Gillies

During the 14 years since the last update to National Instrument 43-101 (NI 43-101), there have been many discussions between Canadian regulators and mining companies about mining disclosure deficiencies that arise from regulatory reviews. These discussions are not made public, and as a result, there has been some drift in how NI 43-101 is interpreted by the regulators, which in turn creates uncertainty for the mining companies trying to comply with the instrument. To reduce uncertainty in mining disclosure requirements, the Canadian Securities Administrators (CSA) has issued a notice to update the current NI 43-101 with a streamlined instrument and form. Changes and benefits are listed in the “CSA Notice and Request for Comment — Proposed Repeal and Replacement of National Instrument 43-101 Standards of Disclosure for Mineral Projects,” which is available on the Ontario, Quebec, Alberta and British Columbia Securities Commission websites. The public has been invited to comment, with the comment period ending on Oct. 10, 2025. The 43-101 Companion Policy (43-101 CP) provides an update to the views of the regulators on how the CSA staff interpret and apply certain provisions of the instrument. Collectively, some of the changes to NI 43-101, the form and 43-101 CP are likely to increase the financial and other burdens on the mining companies responsible for the disclosure, and the qualified persons (QPs) who create the disclosure. In other instances, there are missed opportunities to reduce the burden on mining companies and QPs without impacting the markets.

Sep 1, 2025

By D. Dunbar

The flooding of open pits is now receiving considerable attention from the mining industry as an option that may minimize environmental impacts, particularly when anoxia in pit-lake deep waters can effectively eliminate oxidation of pit-wall sulfides. This paper describes a state-of-the-art, coupled physical-geochemical pit-lake model. The model is used to verify that a controlled, two-stage infilling of the open pit at the Kori Kollo gold mine, southeast of La Paz, Bolivia, would result in a cost-effective, environmentally responsible closure strategy. By filling the pit initially with highly saline surface waters and naturally saline deep groundwater and then capping with fresh river water, a very stable and strongly stratified pit lake will be developed. In addition, the stratification will result in the isolation of metal-rich saline bottom waters from surface waters of good quality. Results of this model provide defensible predictions of the physical stability and evolution of water quality in the Kori Kollo pit lake over time. The model results indicate that anoxic conditions will develop below the fresh-saline water boundary within one to two years, followed by the rapid onset of sulfate-reducing conditions in the bottom waters. Hydrogen sulfide produced by sulfate reduction will readily react with dissolved metals to form highly insoluble metal sulfides. The process results in the gradual removal of metals from the water column and the concomitant improvement of water quality over time. A notable benefit of this strategy is that it can be fully integrated with other mine site closure options as well as future environmental-management strategies. The proposed plan allows for the safe isolation of saline waters, the potential for passive treatment in anoxic bottom waters of ARD seepage from other mine site operations, should they arise, and a repository for future reactive wastes that could be effectively isolated in a physically and chemically stable environment.

Jan 1, 2003

By J. Herbst, J. A. Kitchner, J. P. Anfruns, G. Poling

Measurements have been made of the rate of capture of single particles of strongly hydrophobic, surface-methylated, quartz, of sizes ranging from 12 to 40 pm diam., by single rising bubbles of diam. 0.5 to 1.1 mm. The results agree closely with the theoretically calculated hydrodynamic collision rates, indicating that, in this system, every collision results in capture and retention of a particle.

Jan 1, 1976