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By P. A. Riveros, R. Molnar, F. J. Baša

"An acidification circuit was installed and operated at the Agnico-Eagle Silver Division refinery in Cobalt, Ontario, for treating ~300 m3 of a concentrated cyanide waste solution with the purpose of recovering its cyanide and metal values. The acidification circuit was designed from parameters determined experimentally at CANMET. Available refinery equipment was assembled according to a flowsheet developed by Agnico-Eagle Mines. The process produced a regenerated cyanide solution containing >15 g/L of free cyanide, which was used for leaching gold ore at another Agnico- Eagle operation. It was estimated that the value of the recovered cyanide offset the treatment cost. BackgroundThe Silver Division of Agnico-Eagle Mines needed an economic and effective method for disposing of ~300 m3 of a concentrated cyanide waste solution that had remained in the plant after the operation was shut down in 1989. As a result of extensive recycling and evaporation, the solution had become practically saturated with metals, cyanide, thiocyanate, sulphate and other components, and was, therefore, an environmental liability for the company. A partial analysis of the solution is presented in Table 1. Initially, the use of cyanide destruction methods was considered by Agnico-Eagle, but the estimates indicated a considerable cost with no credits to be gained. A research project carried out by CANMET showed that a simple procedure consisting of acidification, filtration and reneutralization was the most attractive option, because it enabled the recovery of a substantial portion of the cyanide. Furthermore, the metals would be recovered in the form of a solid precipitate. The research showed that conventional AVR was not applicable because of excessive cyanide degradation and low HCN volatilization obtained with this particular solution (Riveros et al., 1996). This paper describes the procedure used to treat the concentrated cyanide waste solution and the operating practices of the large-scale acidification circuit run at the Agnico-Eagle refinery."

Jan 1, 1998

By Launa G. Mallett, Charles Vaught, Michael J. Brnich

Beginning in 1991, scientists at the Pittsburgh Research Laboratory recorded interviews with individuals who are recognized as experts in mine emergency response. These 30 veterans related stories and observations from events experienced during as many as 47 years of response activities. Overall, the response veterans averaged 29 years of mine emergency response experience and 35 years of mining experience. Interviewees included representatives from mining companies, the United Mine Workers of America, and State and Federal agencies. Most of their comments dealt not so much with technical aspects of particular mine emergency responses, but rather the human side of more general topics, including preparedness, experience, people on-site, mine rescue teams, and decision-making. An analysis of their interviews provides an overview of lessons learned on-site at some of the largest mine disasters since the mid-1940s. This knowledge was gathered so that it could be provided to today's miners and to tomorrow's emergency response personnel. It is expected that the collective wisdom obtained can be used to help train new responders and guide those decisions that will have to be made on the scenes of future events.

Jan 4, 2004

By H. T. Mulryan

Talc is used as an essential ingredient in a wide variety of plastics applications ranging from polyester body patch compounds through polypropylene automotive, appliance, and household furniture components to high performance parts made from liquid crystal engineering resins. The paper focuses on polyolefin applications; the three tier market for talc in polypropylene; the effects of various talcs in typical compounds; and trends in each market segment. Emphasis is given to emerging markets, examples of which are polypropylene compounds which mimic higher cost resins, and polyethylene films, customer requirements for talcs for these purposes are discussed.

Jan 1, 1993

By G. Vogt

Water is one of the most important ressources of our planet. Unlike many other natural resources, water cannot be substituted by anything and must therefore be handled with the utmost care. Depending on the region and the possible shortage of water, the importance of water increases even further. Water consumption is not the only factor. In the construction industry, water pollution from auxiliary and operating materials and processes as well as other contaminants and their resulting load on wastewater play an important role. The sources for wastewater on tunneling construction sites are various: Washing water, seepage water accumulating in construction pits, tunnel water, water used in the slurry circuit in fluid-assisted tunneling methods or water from concrete work and stone cutting all these waters are contaminated with a range of pollutants like solids, hydrocarbons, heavy metals, etc. These contaminants can be removed or treated/reduced with the help of specifically designed wastewater treatment plants (WTPs). After the treatment the cleaned water can be either, in best case, reused on the construction site itself or discharged into water utilities like the available sewer or river pin respecting their discharge requirements. Due to dwindling water resources globally, the continuously rising discharge limits and the ever more important aspect of sustainability the use of WTPs on tunneling construction site will be indispensable. In this paper, it will be presented how these systems are designed and work, what advantages they offer environmentally as well as financially and what to look out for when planning and implementing such a system onto jobsite.

Jun 23, 2024

By David Mast, Irwan Halim, Seung Han Kim

Fermilab is constructing a large underground cavern in Limestone to house scientific equipment. The cavern will have a complex L-shaped geometry and about 215-foot depth with relatively shallow rock cover, with service/egress shafts accesses into the cavern. Three-dimensional analytical models were developed to study the ground behavior and support performance. Multiple rock constitutive and failure models were evaluated. The models were significantly impacted by the high lateral in-situ earth pressure at the site. This paper will describe the design approaches that were taken to optimize the cavern arch geometry to allow safe construction in shallow rock, and permanent support requirements.

Jun 13, 2021

By H. William Zeller

The Bureau of Mines is conducting research to determine whether the use of chemical surfactants improves respirable coal dust control and is evaluating laboratory test criteria for selecting effective surfactants. This publication presents the results from wetting effectiveness tests with emphasis on the capillary rise test. The test variables investigated included coal particle size, type of surfactant, surfactant concentration, test duration, and mineral con-tent of the water. In addition to the rise test, measurements of con-tact angle, zeta potential, and sink time for various coal and surfactant combinations were conducted. No significant correlations among the four wetting tests were observed, a surprising result which implies that each test type measures specific aspects of the wetting phenomenon and also that each test type should only be used to select surfactants for specific applications. For example, the rise test shows solution penetration into porous materials, and the sink test discriminates among surfactants for dispersing finely ground materials into suspension. Another important conclusion is that combinations of agents retain their individual wetting properties, allowing mixtures to be for-mulated to perform well in both rise and sink tests.

Jan 1, 1983

By Gilbert Soler

PRODUCERS of alloy steels recognize the importance of chemical composition in rela-tion to the hot-working properties and the typical surface defects found in their prod-uct. Each analysis of steel has its own peculiar characteristics. Under conditions of standard mill practice each analysis is susceptible to certain types of defects. Mill practice must be varied to obtain the best combination of surface and internal quality in the product. Chemical composition influences the cast structure and crystallization character-istics of the ingot. It also determines the rate of heating and cooling, the plastic hot-working range, and the phase structure of the steel at various temperatures as well as the tendency toward scale formation and decarburization, This paper endeavors to emphasize the manner in which chemical composition affects the various properties of steel, and to indicate the relative impor-tance of these factors in relation to the hot-working properties and surface charac-teristics of killed steel. The influence of chemical composition may be outlined as follows: I. Effect on the cast structure of steel, including: A. State of deoxidation, and type of inclusions. B. Gas content of steel. C. Freezing point and melting point of steel.

Jan 1, 1940

By K. D. Jacob, W. L. Hill

THE bulk of natural phosphates is comprised of calcium phosphates, which are usually apatites;1 calcium aluminum phosphates such as pseudowavellite;2 and aluminum phosphates, which occur in extensive deposits, notably on Grand Connetable Island.3 Nearly all deposits of current commercial value are apatite, often with admixed material of other classes. In the trade coarsely crystalline material, mainly fluorapatite of igneous origin, moves as apatite, whereas the fine-grained material of sedimentary origin is marketed as phosphate rock. The latter classification includes the phosphate shales in western North America. Although several genetic varieties of phosphate rock are recognized,4 most known reserves are of marine origin. Calcium phosphate is concentrated from Florida land pebble and Florida hard rock deposits and from Tennessee brown rock deposits. Phosphate Rock as a Fluorine Carrier: More than two decades ago Reynolds and Jacob surveyed the fluorine content of commercial phosphate rock from various parts of the world.3,5 Later these samples were reanalyzed by a new and more reliable method of determining flourine.6,7 The revised results with interim additions of new samples, published a few years ago in a brief summary,' are shown in Figs. 1-3. Through the points representing the respective varieties of rock medial straight lines are drawn. In some instances the lines are well defined by the points; in others, where scattering renders the position of the best line uncertain, the greater weight is given points near the end of the covered range. Wherever distinct varieties are not recognized among regional deposits the custom is to identify the sample with the geographical location of the deposit.

Jan 10, 1954

By P. Coghill, P. Revell

"Geo-sensing is the ability to routinely measure or infer rock properties at a range of scales using non-destructive scanning devices. These devices can provide information and data flows to support integrated decision making across the minerals value chain. Geo-sensing has been used for many years in minerals exploration using technologies such as satellite imaging and airborne geophysics but to date the use of sensing technologies in between the mine and mill has been very limited. The aim of this research is to develop new mineral sensing technologies that can enable grade engineered ore streams through the rejection of low value gangue or deleterious elements either in the pit or during transfer to the mill. This paper focusses on the research and development being carried out by the Cooperative Research Centre for Optimising Resource Extraction (CRC ORE) and its associated members on new sensing technologies. At the start of their development these technologies were classified on the Technology Readiness Level scale at 3 (TRL3), equivalent to a proof of concept. Laboratory testing and design is aimed at progressing these sensing technologies to TRL5 which is ready for testing at an end users site. New data obtained during the laboratory testing and design phases are presented in the paper demonstrating performance specifications such as detection limits and measurement speed which can be used to infer the pod size of gangue that can be rejected at scale. Grade Engineering® and coarse gangue rejection are considered as key drivers for the mining industry to address the higher mining, processing and environmental costs associated with ore bodies with declining grades. This is an industry wide problem and the development of mineral sensors is seen as key enabling technologies for Grade Engineering® and coarse gangue rejection. The technologies presented in this paper enhance value through early decision making of ore quality and improve the overall resource value case through improved grade and throughput engineering."

Jan 1, 2018

By D. M. Hausen

Carbonaceous gold ores are ubiquitous to virtually all of the Carlin-type gold deposits along the Carlin gold belt in north central Nevada, representing the unoxidized "zones" of presumably extinct thermal spring systems of mostly Tertiary age. A period of subtropical weathering resulted in deep sub-lateritic zones in most deposits to several hundred feet below surface. Carbonaceous ores below this supergene profile of weathering have been investigated by various methods, including petrographic study, standard geochemical and organic carbon analyses, carbon and hydrogen isotopic ratios, electron-spin resonance spectra, infrared spectra, and DTA techniques. Results have been integrated with recent findings by other investigators utilizing fluid inclusion and thermal brine data to indicate a first phase hydrothermal solution temperatures and pressures at a minimum depth of 6 km under normal geothermal gradient. This phase resulted in the quartz-barite-calcite vein filling of the host rocks. Gold mineralization took place later at shallower depths. Primary organic material in carbonaceous ores from the Carlin and other mines appears to be a pyrobitumen residue derived from an old oil pool that had been heated by the thermal solutions, and from which the light hydrocarbon fractions were removed. Some of the bitumen was remobilized along silicified veinlets in the ore, but its role in the emplacement of the gold, itself, is not clear. The gold was localized submicroscopically in fine pyrite, mostly in framboids, and as fine metallic particles, but does not appear to be concentrated within the carbonaceous matter per se. However, reducing conditions associated with bituminous residues are believed to have been favorable for gold deposition.

Jan 1, 2013

By ManhKha Trinh, Neal Pyke

Dofasco was the first company to adopt oxygen steelmaking in North America in 1954, two years after the first LD vessel installed and operated successfully in Linz, Austria. Since then, Dofasco has investigated and implemented several strategies to maximize hot metal usage and minimize overall cost. Some key strategies -low hot metal silicon, combined blowing conversion, vacuum degassing tank upgrade and BOF slag carryover control - are discussed. Post combustion, scrap preheat, carbon injection trials along with current operating philosophies are described.

Jan 1, 2004

By T. Carl Shelton

The coal industry of the United States in 1967 had reasons to be both exuberant and concerned about its present and future role in the economy of the country. Continuing a momentum that began in the early 1960's, the industry has moved ahead in providing competitive customized products to strengthen its long-term domestic and foreign commitments, and has maintained with steady progress its position as a major supplier of energy. On the other hand, the industry must overcome air- water pollution and conservation-reclamation problems that have been identified by 1967 legislation. Throughout the year, the industry was characterized as "progressive," "healthy" and "dynamic." To have been termed a "growth industry" in 1967, is an accolade the coal industry can accept with pride. Culminating its efforts throughout the decade, the industry has emerged with a competitive image that is representative of its future strength.

Jan 2, 1968

By Will Jansen

When Enron rocked the United States with its Titanic-sized financial accounting scandal, miners and metallurgists were probably too busy on the mine sites in remote locations to wonder about its ripple effect. But then Enron sank, Arthur Andersen tanked and the list of scandals, costing billions of dollars, continued to ripple. Followed by the Public Company Accounting Reform and Investor Protection Act of 2002 (Sarbanes-Oxley), the recent credit crunch and weak economy, the currents from Enron?s collapse eventually washed right into the mine and the mill. These events placed intense scrutiny on metals production accounting processes as traditional semi-qualitative metal accounting practices provided insufficient credibility and transparency. ?There is growing intolerance of organizations that are unsure about the location of thousands of tonnes of ore, which will typically lose 10 to 15% of their notional value on the way to the concentrator,? Rob Morrison wrote in the opening chapter to An Introduction to Metal Accounting and Balancing. ?If the measurement and forecasts also contain qualitative (fudge) factors, a very real suspicion might emerge about just how much metal might disappear (by theft or misplacement) before detection becomes likely.? Metallurgical accounting, put simply, is the tracking and reporting of the quantity and quality (tonnage and grade, usually) of materials entering or leaving each stage from source to product for a specified accounting period. Lacking an accounting standard, metals accounting in precious metal operations has been performed in an ad-hoc, informal manner, leading to numerous errors and unidentified potentially significant inefficiencies and financial losses. As a result, mining companies are beginning to examine the quality of their metals accounting systems since they form the basis of mining company?s financial accounts and reports. As part of an effort to create that accounting standard in the mineral industry, University of Queensland?s Julius Kruttschnitt Mineral Research Centre published the textbook An Introduction to Metal Accounting and Balancing in 2009. While development of a textbook and standard are significant steps forward, the challenge in the precious metals industry is in the application of some of these suggested practices. Though improving process transparency and precious metals accounting reporting accuracy is a key driver for change from the financial side, perhaps even more important is the potential benefit to operational performance that comes with better measurement, accounting and reconciliation systems. Loss of precious metals, processing of waste and inefficient mining and processing systems are all problems that are faced in an operation on a daily basis that can help be resolved through improvements in metal accounting and reconciliation. The financial consequences of such operational inefficiencies and bad decisions based on poor information are arguably greater than consequences of fraudulent accounting. Large discrepancies between mine and mill measurement systems that measure the quantity and quality of valuable material currently exist. Some of these are expected because of statistical variation, but inherent random measurement variation is sometimes an insufficient explanation. Though the mill can usually make much better production estimates through their measurement systems (that is, less variation), this knowledge rarely benefits the mine. 3 Moreover, even if the mine does a reasonably good job of estimating expected production at the grade control level (in situ), issues such as blast movement, poor mining practice and inefficient ore/waste classification make for a disconnect between the in situ estimates of the mine and the estimates from the concentrator. This inhibits effective evaluation of the reserve and grade control models using concentrator estimates. Linking the two ends, mining and concentration, is a neglected area sorely in need of an overhaul. Hence the need for improved mine to mill reconciliation ? the area of comparing, balancing and adjusting production estimates between mine and mill for consistency in reporting.

Jan 1, 2009

Safety remains a critical priority for the Australian mineral resource industry and will receive increased focus in the future. This is particularly evident in underground coal mines where reserves are becoming deeper and more hazardous to extract. The CSIRO, through its Exploration and Mining Division, have recently delivered on two projects aimed at providing step-change capabilities in real-time risk management and hazard control. This paper describes the key outcomes of these projects.

Jan 1, 2005

By John J. McClelland

The U.S. Bureau of Mines formed a team in 1991 to begin developing a long-range research plan for computer-assisted mining that would benefit the metal-nonmetal mining industry. This report details the team's accomplishments, specifically, the development of a model that identifies metal-nonmetal mining research needs that could be addressed by the application of automation technology. The report also provides a summary of automation needs and applications based on visits with mining company representatives. The status and future direction of this work is also presented.

Jan 1, 1994

By D. W. Struhsacker

Mineral exploration has evolved into a sophisticated science which uses powerful scientific tools to make mineral discoveries. In addition to their usefulness in performing mineral exploration, these scientific tools can assist the exploration geologist in assessing environmental conditions at exploration sites. During exploration, environmental data acquisition should focus on data collection efforts which can be easily integrated into exploration activities, and should provide information needed for pre-feasibility and preliminary engineering design studies. Environmental studies performed during exploration should also include an environmental liabilities audit and a fatal flaw analysis to assess whether there are any unresolvable environmental or regulatory issues affecting the project. Performing extensive environmental baseline studies during exploration and project evaluation is neither necessary nor recommended. This paper describes opportunities to integrate environmental data collection with mineral exploration activities. This paper also examines how political and communication issues can affect the outcome of permitting efforts, and recommends a strategy to improve the industry's ability to respond to political challenges and to communicate with the public. This strategy integrates technical and political issues, and implements programs to convince the public of the mining industry's technological achievements and its commitment to resource stewardship and environmental protection.

Jan 1, 1994

By Zbigniew Lubosik, Andrzej Walentek, Stanislaw Prusek, Sylwester Rajwa, Aleksander Wrana

"Underground coal gasification (UCG) provides a solution to supply electricity from high ash coal or deep deposited seams. The coal is consumed in situ, and, accordingly, the ash is left underground. UCG could play a major role in the future of coal, which is expected to fuel 44% of the world’s energy in 2030, in a more environmentally friendly and commercially viable manner. Nevertheless, it is known that the UCG can impact the environment. One of the most important factors in safe UCG process should be the evaluation of rock mass quality and the monitoring of its behaviour. The changes of rock mass parameters and quality have an influence on numerous aspects, such as subsidence and the stability of underground workings in georeactor vicinity, however, they also increase the possibility of pollutant migration through fractures and pores. These issues are especially important in cases of gasification conducted in an operating mine or on areas of high ecological vulnerability. This paper details observations made in two underground trials of UCG performed in Poland recently. The first of which is the Experimental Mine Barbara (under the project entitled HUGE-2 Hydrogen oriented underground coal gasification for Europe – Environmental and Safety aspects, (Wiatowski et al., 2015). The other trial has been conducted at an operating mine, Wieczorek, which is in the framework of a research project on the development of coal gasification technology for highly efficient fuel and electricity production (Czaplicka-Kolarz et al., 2013). During these trials, investigations were carried out aimed at assessing geomechanical parameters of rock mass and support behaviour in surroundings of UCG geaoreactors. Investigation comprises assessment of geomechanical parameters of coal, floor and roof strata, roof displacements, and concrete support strength parameters variation, as well as standing steel support load. Hydraulic penetrometer, endoscopic camera, Schmidt hammer, pull-out method, telltale, and ground penetration radar (GPR) were used in the investigation. Research conducted at both EM Barbara and Wieczorek Collieries revealed that the UCG process did not adversely affected the competency of rock mass (expressed by number of fissures and strength parameters of rocks), the stability of roadways and the support performance in the areas located in the vicinity of the georeactors."

Jan 1, 2017

By D Chalmers

After the sustained use of the GAG (Górniczy Agregat Gaśniczy) engine at a Queensland coalmine, it has raised questions as to its effectiveness as a remote firefighting tool. All firefighting apparatus have advantages and limitations, however the deployment of any apparatus must be based on its likelihood to succeed and effectively extinguish the fire or bring it under control. A recent study conducted for ACARP by researchers at UNSW has highlighted that there is more to be learned about the GAG. As coalmines are mining at greater depths and fan pressures are much greater than they were when the GAG was introduced, deploying the GAG may be a total waste ofresources and may place operators at greater risk. When the GAG unit is positioned on the surface of the mine, the pressure it generates has to overcome buoyancy of the exhaust gases and the frictional resistance of the borehole and part of the mine circuit. Buoyancy in deeper holes can lead to the GAG pressure relief system opening, venting out the products to the atmosphere without delivering any product to the mine workings. Additionally, frictional resistance is a function of distance. Deeper holes will have a greater frictional resistance than shallow holes. Delivering sufficient products from the unit will be limited by the available pressure that has to overcome the buoyancy, and increased mine resistance thatconsumes any residual pressure. By documenting the limitations of this unit it will enable better decisions to combat a fire or spontaneous combustion event.

Oct 12, 2022

By John J. Dwyer

As one begins to contemplate the organization of a talk with the title "Iron Ore - The Permanent State of Evolution," the main divisions appear to be the past, the present, and the future. But distaste for repetition of the present production achievements, which scarcely need additional description on this occasion, soon leads one to the conclusion that a more appropriate division of the subject is simply the past and the future . . . with emphasis on the future. We are working in the present, but it can only be understood by what has taken place in the years and decades gone by, and/or under what terms we will have to face the future. Evolution is more often thought of as a steady change - but steady change is really the product of revolutions, sometimes making headlines but often unnoticed at the time. With hindsight, we recognize the great importance of the emergence of the Bessemer converter and the open hearth and the vast influence that both have had on steel making and the changing ore demand. In this country we also see schooners opening the era for lake transportation of iron ore from Michigan to Take Erie. Later, steamships haul the ore from the Mesabi Range to the steel centers of the country. In order to take full advantage of the inland seaway, there had to be revolutions in ship design, loading and unloading facilities and channel and lock development. Full scale utilization of the resources of the Mesabi Range, itself, required parallel upheavals such as the development of new production equipment, and substitution of modern forms of energy for horsepower, and, yes, manpower, as well.

Jan 1, 1968

By A. C. Smith, J. H. Rowland III

The Mine Improvement and New Emergency Response Act of 2006 (MINER Act) established a Technical study panel (the Panel) to provide recommendations on the utilization of belt air and new technology that may be available for increasing the fire resistance properties of conveyor belt used in underground coal mines. The Panel Report recommended use of the belt evaluation laboratory test (BELT) as the method for testing and approval of flame resistant conveyor belts used in underground coal mines. The research conducted to establish the correlation of the BELT with large-scale belt fire flammability tests was done using 91 - 107 cm (36- to 42-in.) wide conveyor belt. Due to today’s coal haulage capacity, the mining industry is using 183 cm (72 in.) and wider conveyor belts. The U.S. National Institute for Occupational Safety and Health (NIOSH) conducted a study to determine if the BELT will also qualify wider belts as fire resistant for use in underground coal mines. This paper describes the results of recent experiments comparing results from using the BELT and the large-scale tests for six different belts.

Jan 1, 2011