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By J. G. Groppo, B. K. Parekh

A series of performance studies were conducted using countercurrent column flotation to recover a marketable clean coal product from existing preparation plant fine waste streams. The test work was conducted at several preparation plant sites in Kentucky and Virginia using a 150-mm (6-in.) inside diameter column that was 5.8 m (19 ft) high. Both thickener feed and classifying cyclone overflow with a typical size distribution of 150 µm (100 mesh) X 0 were tested. The percent solids of the column flotation feed varied from 1.5% to 15% while the ash content ranged from about 30% to 60%. The concentrates produced contained 2% to 10% ash with Btu recoveries of nearly 90% using 0.12 to 1.25 kg/t (0.25 to 2.5 lbs per st) fuel oil and 0.12 kg/t (0.25 lbs per st) MIBC. These results were consistent with or better than results obtained in preliminary laboratory scale column flotation evaluation. Test results from seven different seams are discussed as well as scale-up relationships used to design a full-scale installation presently in operation.

Jan 1, 1991

By Richard Addison

Introduction A staccato beat rings out across the Australian bush. The stamps are at work, slowly pulverizing gold-bearing ore for a patient, grizzled prospector. This is the State Battery near Marvel Loch, a tiny 22.6-t/d (25-stpd) capacity gold plant operated by the Western Australia government. It is one of many such plants located in remote corners of Western Australia and the Northern Territory. They are miniature custom mills operated for the benefit of prospectors and small mine operators. These state batteries are so called because they are operated by state governments and because the principal item of machinery in the plants are stamp batteries. They are fascinating anachronisms - throwbacks to times past, a century ago, to the hard and heady existence of gold rush days. Marvel Loch plant Typical of these operations, and perhaps a trifle more sophisticated than most, is the plant near Marvel Loch, a small center for mining and farming about 400 km (250 miles) due east of Perth. Marvel Loch. The name evokes visions of a pristine lake set in a cool, green, misty glen of the Scottish highlands. Actually, it is probably a hot, dry salt pan somewhere nearby. Just where the "loch" is difficult to discern. There is no sign of it on the map.

Jan 7, 1986

By Dan Witkowsky

For the 36th consecutive summer, the Colorado Mining Association Education Foundation and the Colorado School of Mines have sponsored “A Total Concept of the Mining Industry” for kindergarten through grade 12 teachers. Teachers from 34 states, plus the District of Columbia and two foreign countries, have graduated from the four-week course. They received six hours of recertification credit. This summer 31 teachers from Colorado, Kentucky, Virginia and Alaska completed the program. The course is unique from other shorter courses in that it solicits teachers of all disciplines from all K-12classes. In addition to the expected earth science and mathematics teachers, the Class of 2004 consisted of educators who teach music, chemistry, biology, social studies, history, basic English and world history. Others in the program included those who teach American history, physical and life science, remedial reading, consumer/family studies, “world of work,” language arts, engineering technology, environmental science, world geography, human anatomy and physiology, and business.

Jan 1, 2004

By Klimpel. R. R.

Acknowledgments I am honored to be named as a recipient of the Antoine M. Gaudin Award, and I would like to briefly single out four groups who deserve a special thank-you relative to this award. The first group consists of Professor Kawatra, the many international support references that he gathered and the Gaudin Committee itself. I know such things don't come without considerable effort by many individuals, and I'm grateful for their support. The second group consists of the management of The Dow Chemical Company, the managements of various mining companies and, in recent years, the management of G. S. Technologies, all of whom supported me, financially and otherwise, in my grinding, flotation and other particle-processing work. Operations people are the most overworked and under recognized people in the world, whether they be in the mining or chemical industry. Obviously, without extensive industrial support, especially from operating personnel in the mining industry, almost nothing about the work contained in this lecture would have, or could have, happened. The third group consists of a number of coworkers who have played key roles in specifically implementing the new flotation-product portion of this lecture. Of these, Bob Hansen, Don Leonard, Basil Fee, Simon Isherwood, Fernando Cones and Marty Meulendyke deserve special recognition. They have not only been dedicated, but they have been great to work with. Also in this third group are many members of the international academic community, especially those at Penn State. Professor Leonard Austin must be singled out because he took me as a young mathematically oriented chemist and taught me to be an effective process-oriented engineer. Without this experience, I would not have had the over 30-year career as an engineer, which I have loved. In addition, Len planted the size-reduction-research virus in my blood, which I can't seem to get rid of. I also need to mention Professor Frank Aplan, whose obvious love of mineral processing and froth flotation helped to create my interest in flotation. Thus, for those of you who don't like my approach to flotation, it's all Frank's fault. The fourth, and certainly not the least, group to thank is my wife, Charlene, and our two sons, Richard and Steven. No one could have a more supportive family. In every sense of the word, my wife has been my partner from the beginningwe were married at the end of my freshman year in college. She has sacrificed much for me, and I will never really be able to express the depth of my gratitude for Charlene's encouragement, loyalty and support over the past 36 years. General comments on froth flotation The industrial process of froth flotation: Where is it going? I'm here to tell you loud and clear that froth flotation is alive, well, and growing. The inherent characteristics of high mineral throughput per unit of capital, low operating cost per unit of feed, high mineral specificity and high operating flexibility have guaranteed froth flotation an important past and a growing future. As with any evolving technology, there are always trends at the industrial level that are primarily driven by economics. The current trends include: •the movement towards larger and larger equipment, •more alternative equipment designs (e.g., the column cell),

Jan 1, 1996

By LeEtta M. Shaffner, John R. Marks

INTRODUCTION In the last twelve years, underground stoping methods at the Homestake Gold Mine have evolved from open cut-and-fill with jacklegs, cribbed raises and electric slushers to ramp-based mechanized cut-and-fill (MCF) and vertical crater retreat (VCR) with dieselpowered loaders, trucks and drill jumbos. The evolution was swift. Unfortunately, ventilation practices have had trouble keeping pace. Stope ventilation is still too dependent on auxiliary fans and coolers. A single large MCF stope might contain up to eight headings, each of which requires significant ventilation resources when a diesel loader is present. Air is shortcircuited all too frequently through mined-out VCR panels. These factors and the recent rapid decent of the center of mining prompted a study to improve ventilation practices and to more accurately project future requirements. BACKGROUND In 1992, the underground portion of the Homestake Gold Mine produced 8336 kg of gold from 1407 ktons of ore (268,000 oz from 1,551,000 st). The ore is hosted in low to medium grade meta-sediments. Stoping took place from 420 to 2347 m below the surface (1400 to 7700-ft levels). The weighted center of mining was 1662 m deep (5450-ft level) in 1990 and is projected to be 1890 m (6200-ft) in 1993. The deepest level is 2440 m (8000-ft) where the virgin rock temperature (VRT) is 56.1°C (133F). The mine is ventilated by 504 m3/s (1,069,000 cfm) measured at mid-exhaust-circuit density. The air-conditioning system includes an 8.1 MWR (2300 ton) controlled recirculation plant, a 2.0 MWR (580 ton) chilled water plant, a 1.0 MWR (290 ton) exploration drift refrigeration plant, 28 spot-coolers totaling 3.4 MWR (960 tons) and 35 spray coolers totaling 1.5 MWR (420 tons). The mine employs 117 diesel units with a total nameplate rating of 7961 kW (10,672 hp). These units include twenty-four 1.5m3 (2-yd) loaders, twenty-six 2.7m3 (3.5-yd) loaders, fourteen 3.8m3 (5-yd) and two 7.6m3 (10-yd) trucks, and assorted utility vehicles and drill jumbos. THE STUDY In April 1991, the University of Nevada-Reno (Mackay School of Mines) and the South Dakota School of Mines and Technology cooperated with Homestake on an MCF study. Mackay instrumented a stope with thermocouples, air velocity meters and hygrometers (Duckworth, 1992). South Dakota Tech conducted a finite-elements computer analysis of a back-filled MCF stope with/without light-weight shotcrete insulation on the sidewalls and back (Chellam, 1992). Homestake conducted an empirical analysis of deep-level MCF stoping. This paper describes the Homestake study. Twenty-three of the forty MCF stopes deeper than 1800 m were surveyed at least once during the last quarter of 1992. The stopes not included were being cable-bolted or back-filled. Figure 1 shows the complexity of one of the ramp-based stoping areas included in the survey. This particular stope has six separate production headings. A baseline wallrock heat load was derived for each stope or heading from psychrometric calculations. Broken ore, waste rock fill and fissure water were noted when present and the effects included in the baseline heat load. Other heat sources often mentioned in the literature such as metabolic heat from workers, heat from explosives and small electric loads were neglected. Fan heat was considered part of the ramp & crosscut heat load and thus not included in the study. Diesel heat was addressed separately. RESULTS Survey results, plotted as the heat flux against VRT, are shown in Figure 2. The equation for the regression line is: W/m2 = 2.1236*VRT - 75.405 The 0.31 correlation coefficient is poor which implies that the results should be used cautiously. Previous experience strongly suggests that differences in productivity are most likely responsible for the scatter in data points. A rapidly advancing stope will have a

Jan 1, 1993

By L. Gutierrez, S. Gering, C. Calderon-Arteaga

"Drill and blast represent the most important, and sometimes the costliest processes in the mine. The cost of drilling and blasting operations greatly contributes to the “high cost trends of the overall mining operations” (Afum and Temeng, 2015). The use of available information to improve the drill and blast processes can be the difference between a wasteful process and one that is optimized for costs, safety and desired fragmentation. Mining operations have access to several types of data sets that include a variety of different systems. This information can be used to improve, evaluate and apply processes for drilling and blasting. This may include different types of data from the different stages of the process (before, during and after the drilling and blasting operations), such as hole locations (planned and actual), penetration rates, drill operators, fragmentation (expected and resulting), explosive (design and usage), geology, vibration and others. This information can be used on its own or combined for further analysis to reduce costs, improve safety and evaluate results. Fortunately, due to advances in mining software, drill and blast engineers can exploit this data and create reports to evaluate results and improve the drill and blast process. However, as users start combining information from multiple datasets and establishing standard operating procedures for reporting across multiple sites, it becomes valuable to create auditable, automated and sustainable workflows for handling the information.In some cases, the task of aggregating and standardizing the data formats has already been completed and is available to consumers via the Enterprise Data Warehouse (EDW). A data warehouse team extracts data from the source systems and transforms it so that it is meaningful for decision support (Wixom, Watson, 2007). The author’s initial implementation plan for the drill and blast solution included using data stored at the sites on local servers. However, we learned early in the process that much of the work for aggregating and supplying the required data was already completed and was available in the EDW ready for use. This saved time, reduced risk and added value to the system.The goal for this case study is two-fold: to show how information can be used to make decisions and improve processes, especially highlighting the value of using an EDW for managing drill blast information; and to discuss how technical challenges encountered during the implementations were resolved. This article targets users that want to better manage their drill and blast data or try to set up standardized workflows for using this information.This case study will discuss the process of implementing a drill-and-blast workflow at multiple sites within Freeport-McMoRan (FMI) using both data at the sites and information available from the EDW."

Jan 5, 2017

By R. D. Schmidt

An in situ leaching geochemical simulator consisting of flow, mass transport, and graphics support programs has been developed. Two dimensional flow in heterogeneous porous media is modeled using a semi-analytic boundary integral technique. This method involves mapping streamlines to straight line segments in the complex potential plane. Leachant concentration and mineral values are modeled in this plane using the (one dimensional) potential coordinates. A fully implicit finite difference scheme is used to solve the resulting coupled system of four concentration equations. Graphical representations of streamline patterns, concentration histories, profiles and recovery curves are generated. An application of the model to uranium leaching in a heterogeneous aquifer and ore zone setting is presented.

Jan 1, 1985

By Robert J. Wise

The mine plan for an underground longwall mine plan usually requires a longwall panel conveyor that begins operation at its maximum length and gradually shortens over the life of the panel. Current mine plans around the United States require initial panel conveyor lengths of up to 4500 m (15,000 ft) and capacities of up to 3.2 kt/h (3500 stph). Because these conveyors are constantly being moved from panel to panel, their components must be as compact and light as possible, and the design must be flexible enough to be modified as new terrain and conditions are met. In the past, when drive horsepowers or belt tensions were exceeded due to conveyor length, a new flight would be added, including additional belt storage units. In some cases, this led to as many as three flights installed in a single longwall panel. As the longwall retreated through each flight, mining was required to stop during removal of the drives and storage units. This sometimes meant several days of lost production. Intermediate drive technology was developed to eliminate this excessive downtime and still keep conveyor belts, motors, pulleys and other components as small as possible. With intermediate drives placed along the carrying side of the conveyor, belt and motor sizes are kept as small as possible, and only one storage unit is needed. Most importantly, as the longwall retreats through a booster drive station, it can generally be removed in a regular downtime slot and no additional production time is lost.

Jan 1, 1993

By Klaus Beckmann

Gentlemen : My object reads "Longwall Rapid Advance of Coal Mining in the Federal Republic of Germany". It is true that the percentage of coal obtained in your country from longwall faces, with at present 1.2, is still rather low, but it increased considerably since 1966 with 0.4 %. The coal mines of the Federal Republic of Germany ever used longwall as the classical method of coal getting. All attempts to introduce bord and pillar mining did not lead to any wider application of this method. The principal reasons, for this appear to have been: - the deeper depth of our workings, - the wish to keep working losses as low as possible and to utilize the deposits opened up by deep and therefore expensive shafts to the furthest possible degree, - the dense sequence of seams and the mutual influencing of the working points, - the high number of disturbances in the geologically much stressed deposits, - and the necessary considerations to the protection of the densely built-upon surface.

Jan 1, 1970

By Jamai Rostami

Mining, perhaps more than other industries, has been under pressure to achieve higher productivity, while reducing costs and environmental impacts. This has encouraged a move toward large-scale operations and greater integration and automation of systems. Mechanization is being used increasingly to raise production and reduce labor requirements. Yet, while transportation, ventilation and other activities have benefited from this trend, mechanization of rock excavation (for development and production) has lagged. The switch to a mechanized excavation system can be complex, requiring a thorough study of operational and cost benefits to be successful. To justify the high capital cost of mechanical mining equipment, production rates and the true costs of machine mining must be accurately estimated. To evaluate the cost effectiveness of mechanical mining for a particular operation, the total production cost (capital and operating) must first be estimated. This requires a reliable estimate of the production rate of the candidate mechanical excavator. Previously, the variable nature of rock caused performance prediction of these machines to be more an art than a science. Additionally, some of these machines are highly sensitive to operator skill. They all depend on their backup systems. The effects of interaction with the overall mining operation can be difficult to forecast. And a new system must surmount psychological barriers before it can become truly operational.

Jan 1, 1994

By B. C. Flintoff

In general, process control systems in solid-solid separation have not evolved to the same level as in flotation circuit control. Perhaps one of the more significant contributing factors in this regard is the lack of suitable on-line analytical instrumentation. In spite of the obstacles, some interesting work has been done. This paper presents a review of current industrial control strategies in ore sorting, dense media separation, gravity separation and electrical and magnetic separation.

Jan 1, 1986

By Robert Moore Lewis

Extensive exploration is being undertaken throughout the world in search for heavy minerals, particularly rutile and other titanium minerals. The federal government is sponsoring research involving rutile ores and recovery of stockpile-grade concentrates from domestic sources. Producers are being forced to turn to deposits with a heavy mineral content as low as 0.50% (essentially rutile and zircon). The North Carolina State University Minerals Research Laboratory investigated the possibilities of recovering heavy minerals from the amine tailings of the Texasgulf Inc.'s phosphate plant at Aurora, North Carolina. One laboratory beneficiation procedure using gravity, electrostatic and magnetic processes, resulted in the recovery of 78.7% of the heavy minerals in the amine tailings. Based on this percentage recovery and the present rate of phosphate mining, approximately 13,000 tons per year of heavy minerals (principally ilmenite and zircon) with a potential value of approximately $1,045,000 (1977) could be recovered. The economic potential for recovery of these heavy minerals appears to be favorable. A flotation procedure for up-grading the heavy minerals content in the amine tailings has been developed at the Laboratory, which could allow for concentration of heavy minerals and storing them in tailings area other than main tailings for future processing.

Jan 1, 1978

The Mine Safety and Health Administration (MSHA) academy in Beckley, WV, received enquiries from various segments of the mining industry concerning alcohol and substance abuse in the mining industry. The MSHA Director formed a committee, the Mining Industry Committee on Substance Abuse (MICSA), to deal with these enquiries. The committee met in April 1985 at the mining academy in Beckley. The MICSA committee expanded its membership to represent labor, management, and government agencies affiliated with the mining industry as well as government agencies dealing with alcohol and drug abuse. This expanded 18-member committee met for the first time in July 1985. At that time, two cochairmen were elected, one from labor and one from management. MICSA has spent time on education by sharing information on the issues and by calling in outside experts for advice and consultation. The committee also initiated several projects. These include a resource manual on substance abuse and employee assistance programs. Mine operators and labor unions can use these programs as guides. MICSA is also assembling statistics on substance abuse, particularly as applied to mining. And the committee commissioned an Education film, Substance Abuse, Is It Our Problem? (The results of a survey on drug use, given in Table 1, suggest that substance abuse may indeed be a problem.) The educational film, produced by MSHA, is an introduction to the problem of substance abuse in the mining environment. The film encourages mine operators, labor unions, and miners to analyze their individual circumstances to determine whether a problem exists. The film also offers ways to deal with the problem. And the film invites the mining industry to request additional information from MICSA. There is no single approach to substance abuse that will fit the need of every mining operation. As with any health, safety, or production problem, remedies must be site specific. MICSA's aim is to channel ideas to those who seek to help employees in a mining environment who seek to rid themselves of alcohol and substance abuse. As stated more formally: The Mining Industry Committee on Substance Abuse represents the efforts of labor, management, and government. The mission of the committee is to make the mining industry aware of the problems resulting from alcohol and other drug abuse and to recommend possible methods to remedy the problem. The function of the committee is to assist the industry in developing programs and resources to recognize and provide help for troubled employees, and thus reduce the risk of accidents, while lower absenteeism and increasing productivity.

Jan 11, 1987

By V. L. Andrade, K. L. C. Goncalves, N. A. Santos

This paper describes results obtained in a test program performed with new equipment, called Mini Pilot Plant, manufactured by Canadian Process Technologies. This equipment was acquired by CVRD aiming at testing flotation circuits, in a continuous closed configuration, with samples obtained from drill cores. Success of this goal would allow CVRD to establish the metallurgical performance of mineral deposits with more confidence in comparison to Locked Cycle Tests (LCT). This paper discusses the importance of assessing the ore variability and compares results obtained in LCTs and Mini Pilot Plant. Results suggest that more reliable data is obtained in MPP test.

Jan 1, 2002

A Mark IV surface force apparatus (SF A) was used to conduct direct force measurements in dodecylamine hydrogenchloride collector solution between mica surfaces at varying pHs. It has been found that the long-range hydrophobic forces reach a maximum at pH 9.5, which also corresponds to the maxima attained by the contact angle and flotation recovery of quartz. The charge densities are comparable on both mica and quartz surfaces (0.40-0.48 run2), making it possible to draw conclusions on the flotation of quartz from the direct force measurements conducted on mica. Therefore, it may be suggested that the maximum flotation recovery of quartz m the range of pH 8.0-10.3 may be attributed to the appearance of long-range hydrophobic force, which in turn can be related to the formation of a close-packed monolayer (or hemimicelle) in the presence of neutral amines formed as a result of hydrolysis.

Jan 1, 1996

By Steve Axen

In situ mining is now considered an alternative mining method for some ore bodies. The in situ operation consists of a well field designed from reservoir properties and geological information; the wells for such a field are then drilled, cased, and cemented, using good designs and practices to eliminate future problems. Injection and production (recovery) systems are required to be corrosion resistant. Hand in hand with the mining operation is the metal extraction plant, the entire operation offering an environmentally acceptable method for metal recovery. Great opportunity exists in this field for mineral engineers; presently, they must borrow knowledge from other fields, since the schools have not yet addressed this specialty.

Jan 1, 1979

By David Belknap, Clay Haynes, David Egger

Rehabilitation challenges were met nearly two months ahead of contract schedule for the Design-Build, Fast Track Scituate Aqueduct & Tunnel project in Cranston, Rhode Island. The aqueduct and tunnel were built in the 1920s and consisted of three sections—a 2.3 m diameter reinforced concrete section that extends approximately305 m before it transitions to a horseshoe-shaped 2.3 m wide by 2.1 m high cast-in-place concrete tunnel that continues for approximately 5.3 km until it transitions back to a 2.3 m circular section that extends approximately 1.9 km to the end of this project. Major repairs were required to assure sustained operation of this water supply tunnel.

Jan 1, 2005

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 Graham Davey

High-speed stirred milling is a relatively new method of grinding in the metalliferous process industries. However, it has been widely used in the industrial mineral field for more than 30 years. Many existing metallurgical operations are looking to maximize economic return from existing deposits this requires new thinking and technologies. The operating experience of two copper operations is discussed here to show the effect of the introduction of the Metso Stirred Media Detritor (SMD), a new type of high speed stirred mill. Both operations have derived significant metallurgical benefits from this new technology. The benefits and process difficulties are explained. The initial drive in high speed stirred milling technology was toward ultra fine grinding where the mill product has an 80 percent passing size of 15 µm (937mesh) or less. More recently, a number of installations have occurred in a more conventional regrind setting. Few conventional copper concentrators require such fine grinding to attain satisfactory copper grades and recoveries. So other advantages must be considered here rather than just the ability to grind fine with good power efficiency.

Jan 1, 2004

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