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By P. R. Taylor

A review of the advantages and disadvantages of plasma technology for metal and mineral wastes is presented. Examples of the use of plasma systems are given and possible future uses are outlined. Among the potential uses are treatment of electric arc furnace (EAF) dusts, the vitrification of nuclear wastes and the removal of toxic metals. Over the past few decades, plasma technology has been studied for potential applications over a wide range of metals/materials processing areas. One promising area of plasma technology applications is the treatment of industrial hazardous waste. The potential generation of hazardous and toxic waste by various industries has become a matter of public and political awareness. Environmental regulations have put stringent toxicity emission limits on disposable waste streams. An intensive research effort is currently underway in the area of hazardous waste treatment.

Jan 1, 1994

By P. M. Keyser

Column flotation continues to make inroads into applications traditionally dominated by mechanical flotation cells. For example, columns are becoming more visible as rougher flotation devices. At Royal Mountain King Mine in California, two 2.9 m (9.5 ft) diameter columns are used for rougher flotation of carbon from a gold ore (Orlich et al, 1992). In addition, work performed at BRGM in France demonstrated the superiority of column flotation over mechanical flotation with respect to design of new plants (Morizot et al, 1991). With the mounting evidence, columns can succeed in any flotation application. The primary reasons for this acceptance of columns are a general improvement in design, scale-up and operation as well as improvements in sparger design and performance. With these advances, the full benefits of column flotation can be realized. The benefits of properly designed, aerated and operated flotation columns include: ? Lower Capital Costs ? Reduced Operating Costs ? Fewer Processing Stages ? Improved Metallurgical Performance

Jan 1, 1993

By T. Bartnitzki, N. Fietz

"INTRODUCTION For a long time now automation has been state of the art in production engineering and chemical engineering. The advantages of automation are, for instance, higher reliabilities of production processes, higher product qualities as well as capacities and improved safety conditions for the personnel. In contrast, many operations in mining are still conducted manually by machine operators instead of autonomous control units. One example for this is the excavation of underground hard coal which is still executed with aid of human perception. The Institute for Mining and Metallurgical Machinery (IMR) has been working on possibilities for sensor-based automation of mining machinery for many years now. Thereto the focus is set on the implementation of common material analysis techniques into ruggedized conditions as a basis for automation. Laser-induced breakdown spectroscopy (LIBS) for instance is an atom emission technique which enables the determination of the elemental composition of a sample. After introducing LIBS this paper will give an overview on dust formation during the cutting process. With the illustration of a few examples the challenges in determining dust concentrations specifically such of cutting processes are explained in further detail. The final chapter will outlay the possibilities and challenges in utilizing cutting-induced dust for the automation of shearer loaders. LASER-INDUCED BREAKDOWN SPECTROSCOPY LIBS Fundamentals LIBS (laser-induced breakdown spectroscopy) is a contact-free method for analyzing materials in any state of aggregate. It pertains the atom emission techniques and is based on the generation of plasma, inducing avalanche ionization on the surface of a solid material or any spot in a gas or aqueous solution. With sufficient background information on the expected elements and an additional calibration, this method can determine all present elements not only qualitatively but also quantitatively. However, this method cannot be utilized for determining the molecular composition of materials – if this feature is required a complementary method such as Raman analysis needs to be added. (1, 2)"

Jan 1, 2015

By D. Berberick, G. Sturgis, M. Board, B. Strickland

"Hecla Limited is nearing completion of the Lucky Friday Mine No.4 shaft located in Mullan, ID. The shaft is collared at the 4940 level of the mine and will have a final mine level depth of 8620, or 9,590 feet below the surface. After reaching the 7400 mine level the shaft encountered ground deformation higher then allowed for in the design for a circular shaft excavation and concrete lining. This additional ground deformation required portions of the shaft concrete liner to be reinforced with frameless, steel liner plate. To eliminate the installation of the liner plate from the remaining shaft development, the design of the shaft excavation starting at the 7650 mine level was changed to an elliptical cross section based on the overall stress field orientation as well as the orientation of the structure of the host rock surrounding the shaft. The elliptical cross section was instrumented to confirm the shaft excavation and lining was performing as designed. This design change has allowed the shaft to continue to the planned 8620 mine level without the need to install liner plate in the shaft or change the overall functionality of the shaft or the Lucky Friday life of mine plan.INTRODUCTION Hecla’s Lucky Friday Mine is a deep, underground producer of silver, lead and zinc in the Coeur d’Alene mining district of northern Idaho (Figure 1). Primary access into the mine is via the Silver Shaft, a 5.5-m (18-ft) diameter, concrete lined shaft sunk to an original depth of 1,890-m (6,200-ft). Current production is from the Gold Hunter vein system, approximately 1,525-m (5,000-ft) northwest of the Silver Shaft.Lucky Friday’s #4-Shaft is a 5.5-m (18-ft) finished diameter, internal shaft, or winze, being sunk to the north of the Gold Hunter vein system, from the mine’s 4760 level, 1,743-m (5,720-ft) below the surface, to the 8620 level, 2,923-m (9,590-ft) below the surface. The shaft is designed to provide access to the deep, high-grade zones of the Gold Hunter in order to increase the mine’s production and operational life. Design and engineering began in 2006, with construction starting in the fourth quarter of 2009."

Jan 1, 2016

By L. Yan, T. Lutz, J. Noll

"Mine disasters, such as fires and explosions, can create a hazardous atmosphere due to the generation of carbon monoxide (CO). After a mine disaster, contaminated mine air can enter the refuge alternative (RA) as miners enter. Most built-in-place (BIP) RAs use an air delivery system to provide an unlimited supply of breathable air through a borehole which also serves to purge contaminants. In order to determine what levels of contaminants enter the RA, researchers from the National Institute for Occupational Safety and Health (NIOSH) conducted testing in NIOSH’s Pittsburgh Experimental Mine using groups of 5, 15, and 30 subjects entering the RA. The experiment used sulfur hexafluoride (SF6) as a tracer gas that was released into the air outside of the BIP RA to establish a uniform concentration. After the human subjects entered the BIP RA, the SF6 levels inside the RA were measured to quantify how much of the tracer gas entered the BIP RA. In tests conducted while the borehole air supply was left off as test subjects entered, interior contaminant levels were less than 3% of the exterior concentration. In tests conducted with the borehole air supply activated as test subjects entered, the interior contaminant levels were measured at less than 2% of the exterior concentration. Considering a mine disaster can result in 10,000 ppm of CO in the mine atmosphere, these percentages indicate that unhealthy CO concentrations that may lead to headaches, dizziness, and loss of judgement can occur in a BIP RA. This information will help mines make decisions concerning air locks, air delivery systems and a determination if purging mechanisms are necessary. INTRODUCTION The Mine Improvement and New Emergency Response Act of 2006 (MINER Act) was enacted in the wake of three mine explosions/fires that claimed 19 lives that year. Intended to help improve underground coal mine accident preparedness, the MINER Act includes provisions that target mine safety issues in areas such as emergency response planning, adoption of new technology, training and education, and enforcement of mine safety standards (MSHA, 2006). Section 13 of the MINER Act specifically directs the National Institute for Occupational Safety and Health (NIOSH) to provide for research into the effectiveness and viability of RAs for underground coal mines. This mandate culminated in the 2009 adoption of changes to the 30 CFR mining health and safety regulations, requiring underground coal mines to provide RAs capable of maintaining a life-sustaining environment for persons trapped underground. Such RAs can be either pre-fabricated or BIP shelters. The regulatory changes also include provisions establishing requirements for Mine Safety and Health Administration (MSHA) approval of RAs and their components, and among these provisions are numerous criteria for providing a safe, breathable atmosphere within RAs."

Jan 1, 2018

By J. G. Pippenger

The Coteau Properties Company's Freedom Mine is a surface lignite mining operation utilizing large draglines, trucks and shovels, tractor-scrapers, and bulldozers to uncover a single coal seam. In 1989, a work order system was instituted to record data by equipment type, cost, productivity, and distance, and to provide historical information for planning the most efficient and economic use of each equipment type in the mining operation. This report explains how the work order system was initiated, what data is tracked, and how the data is utilized for equipment and project scheduling.

Jan 1, 1994

By D. W. Hendrickson

Cliffs views the process as extending from mine planning to cargo loading including auxiliary systems such as material handling and plant utilities. Process automation is recognized as an area that can provide significant improvement opportunities with less capital requirement than major flowsheet modifications. This paper discusses the development and results of a strategy to allow and promote implementation of process automation improvements at individual mines based on their economic priorities taking advantage of common systems and concepts for use at multiple mines where practical. Specific process control upgrade projects a Hibbing Taconite Company and the Empire Mine are reviewed in detail.

Jan 1, 1998

By J. A. Porter

This paper uses project examples, primarily associated with large iron ore mines in Brazil, to demonstrate opportunities for the mining industry to go beyond traditional compliance and impact mitigation to proactively operate within the ethics of environmental and economic sustainability.

Jan 1, 1994

By L. M. Pruett

The Arizona Legislature is currently in the process of considering mined land reclamation legislation in the 1994 legislative session. A bipartisan legislative study committee has drafted proposed mined land legislation. The committee has attempted to craft legislation that is appropriate for the unique conditions in Arizona. Existing Arizona and federal laws and regulations extensively regulate the environmental performance of mines in the state to protect public health, safety and the environment. The proposed mined land reclamation legislation does not replace or duplicate these statutory provisions relating to environmental protection. Instead, the purpose of the proposed legislation is to provide for the reclamation of land that is being mined and to fill the gap in existing laws by requiring the reclamation of land that currently is being mined or that has been mined since 1986 to provide for future land use. The legislation would require an operator to submit a reclamation plan describing the exploration operations, mining operations, post-mining land use and the proposed reclamation measures for review by a state agency. Financial assurance also would be required in an amount such that a third party could complete the approved reclamation measures. Arizona's mined land reclamation legislation would recognize Arizona's leading role in hard rock mining and emphasize the mining industry's economic importance to Arizona and the nation. Because mining operations necessarily require disturbing the surface of the earth to extract valuable minerals, reclamation requirements would be adapted to different conditions and would vary depending on site-specific conditions and on the commodity being mined. The current proposal does not identify the state agency that will administer the mined land reclamation program and approve reclamation plans, substantial changes to plans, and transfers of reclamation plans to other operators.

Jan 1, 1994

By J. Szarkowski

"INTRODUCTION The Butte district of Montana is well-known as one of the biggest historic producers of copper in the world. It is also a classic example of a porphyry Cu-Mo system that has been overprinted by zoned, polymetallic (Cu-Zn-Pb-Ag) lode mineralization. After copper, silver was the next most important metal mined from Butte, with over 700 million ounces of total Ag production between 1880 and the present day. Although many papers have been written on the mineralogy of the early porphyry Cu-Mo mineralization and the high-grade Cu-rich lodes in the center of the district, relatively little information exists on the mineralogy of silver in Butte. The purpose of this paper is to summarize past and present silver production trends for the district, and to combine previously published work with new research to examine the mineralogy of silver in the Butte mining district. BUTTE HISTORIC SILVER PRODUCTION According to a recent USGS compilation1, Butte is one of the most Ag-rich porphyry deposits in the world, both in terms of average Ag grade (8.6 g/ton) and total production + reserves (Fig. 1). It is also the 2nd biggest Ag-producing mining district in the U.S. (after the Couer d’Alene district, Idaho). Annual silver and copper production data for the Butte district, compiled from various sources2,3,4, are summarized in Figure 2. Peak production of Ag and Cu was in 1917. While Ag production gradually declined in the ensuing decades, Cu production remained strong until the years leading up to the closure of the Berkeley Pit in 1982. In 1984, mining of the nearby Continental Pit resumed under a different operator, and continues to the present day. The Continental mine produced an average of 35,000 metric tons Cu and 575,000 oz Ag per year between 1984 and 20044. These figures do not take into account a period of mine closure in 2001-2003 due to an unexpected hike in utility prices. The long-term decline in Ag/Cu ratio of ore mined in Butte (Figure 3) is due to several factors, including: 1) changes in metal prices; 2) a downwards decrease in Ag/Cu ratio of most of the lodes with depth below surface; and 3) a shift in mining methods from selective underground mining of high-grade veins to open-pit mining of the bulk rock."

Jan 1, 2016

By A. L. Miller, A. J. Chambers, P. R. Griffiths, D. A. Parks

"Diesel engines are one of the primary contributors to the presence of nano and ultrafine aerosols in ambient air and occupational environments. Exposure to diesel emissions has been shown to contribute to various adverse health outcomes of the pulmonary system and cardiovascular system. Currently diesel emissions in the workplace are monitored by way of collecting the aerosol onto filters, which are then sent to a lab for thermal-optical analysis using the NIOSH 5040 method, which measures elemental and organic carbon explicitly. This process can take days or even weeks, and workers can potentially be exposed to excessive levels of diesel particulate matter (DPM) before the problem is identified. To remedy this, researchers from the National Institute for Occupational Safety and Health (NIOSH) are seeking to develop a field-portable method for measuring elemental and organic carbon in DPM aerosols. In the current study, we investigated the use of Fourier transform mid-infrared (FT-IR) spectrometry, which lends itself more readily to implementation in a real-time system than do the thermal-optical analysis methods. We have demonstrated a method for measuring organic and elemental carbon in DPM for a broad range of organic carbon (OC) to elemental carbon (EC) ratios (from 50.3 to 0.8). The ability to handle a wide range of OC to EC ratios is critical given the evolving diesel technology. INTRODUCTION Respiratory illnesses are common in mining industry workers [1] and exposures to toxic aerosols such as DPM can result in serious respiratory illness [2]. Health studies show a correlation between workplace exposure to diesel exhaust and an increased risk of lung cancer [3-8]. The International Agency for Research on Cancer (IARC) has characterized diesel exhaust as a human carcinogen [9], and similar classifications have been made by the World Health Organization and the California Air Resource Board. A recent study [10] suggests that the risk of lung cancer is approximately three times greater for heavily exposed workers. When compared to other aerosols in the mine environment, the settling time of DPM is significantly longer than that of dust due to their small particle size (typically < 1 µm) [11]. Additionally, submicron particles (such as DPM) are deposited in the lungs much more efficiently than their larger counterparts such as dust [12]. Previous studies focusing on particle morphology [13] show that the largest mass contributor to lung disease in mining is elemental carbon, which provides a solid core onto which hydrocarbons are adsorbed. In accord with those findings the Mine Safety and Health Administration (MSHA) decided on submicron total carbon as a surrogate for monitoring diesel particulate matter in the mining environment."

Jan 1, 2018

By K. H. McDaniel

An interactive mine ventilation simulation software program (WIPPVENT) was developed at the Waste Isolation Pilot Plant (WIPP). The WIPP is a U.S. Department of Energy (DOE) research and development project located near Carlsbad, New Mexico. The facility is designed to provide a permanent, safe underground disposal of U.S. defense generated transuranic waste in bedded salt. In addition to its regular functions, the underground ventilation system is engineered to prevent the uncontrolled spread of radioactive materials in the unlikely event of a release. To enhance the operability system, Westinghouse Electric Corporation has developed an interactive mine ventilation simulation software program (WIPPVENT). While WIPPVENT includes most of the functions of the commercially available simulation program VNETPC (copyright © 1991 Mine Ventilation Services, Inc.), the user interface has been completely rewritten as a Windows ® application and screen graphics have been added. WIPPVENT is designed to interact with the WIPP ventilation monitoring systems through the site wide Central Monitoring System.

Jan 1, 1996

Ceremonies for the induction of four mining industry pioneers into the National Mining Hall of Fame will be held Saturday, Sept. 11, 2010 at the Charles F. Barber Pavilion of the Museum Convention Center in Leadville, CO. The 23rd Annual National Mining Hall of Fame and Museum Banquet will begin with an open house and reception at 5:30 p.m., followed by the dinner and program at 7 p.m. The four inductees are: William Wheeler Coleman who served 46 years, from 1911 to 1957, as president and chairman of the company that is now Bucyrus International of South Milwaukee, WI, a world leader in the manufacture of surface and underground mining equipment. Dr. Allen Van Heyl, Jr., an economic geologist who served with the U.S. Geological Survey for nearly 50 years beginning in 1943. He studied more of the nation?s mineral deposits than most could begin to imagine. Arthur Lakes contributed enormously to the geological and mining sciences in the western United States as a geologist, teacher, writer and artist over a period of more than four decades beginning in 1869. The Arthur Lakes Library at the Colorado School of Mines, Golden, CO, is named for him. Samuel Calvin McLanahan, through his inventive genius, changed the direction of his family?s company from that of a foundry to a leading manufacturer of minerals processing equipment to become today?s McLanahan

Jul 1, 2010

By PDF

Previous work has shown that significant, free milling gold values exist in the Ryan Lode ore. This project used pilot scale equipment to estimate the percentage of gold recoverable by gravity methods from the circulating load of a conventional, closed-circuit, grinding mill. The pilot scale flowsheet employed three stages of gravity concentration, hydraulic classification and batch grinding to simulate a full scale milling circuit. 172 kg (379 lbs) of Ryan Lode ore were processed, having a head grade of 4.8 g/metric ton (0.14 oz/ton). Results showed that simple gravity methods are capable of recovering 45-50% of the gold values in a concentrate grading in excess of 3430 g/metric ton (100 oz/ton). Of the remaining gold values reporting to the classifier overflow solids (80% passing 70 microns, 3.1 g/metric ton (0.09 oz/ton)) 89% were recovered from 48 hour bottle roll tests.

Jan 1, 1995

By D. F. Cater

The Macassa Mine is a mature mine with a 61 year history of continuous production. The majority of past production has been derived from a zone called the &apos;04 Break (Main Break). Recent underground mine exploration has been successful in locating several neighbouring ninera1ized zones. This paper will characterize the spatial location, geometry and mineralogical properties of these secondary zones. Future plans for underground mine exploration to follow-up on these target zones will be outlined.

Jan 1, 1995

By T. A. Toney

With new lightweight designs, spirals have become standard equipment in coal preparation plants worldwide. To their credit, spirals typically show very low coal losses to the refuse stream under most operating conditions. However, spirals do tend to separate at cut points in excess of 1.80 S.G. Attempts to obtain lower cut points have typically resulted in coal losses to middlings. Middlings retreatment with secondary spirals is therefore becoming common place. Other forms of retreatment with water-only cyclones, hydrosizers, and recirculation have been attempted with some success. This paper reports on a novel (Patent Applied For) approach to retreating spiral middlings m a heavy-media-cyclone circuit.

Jan 1, 1998

Federal Regulations require that coal producers conduct a written, in-house investigation with every lost time injury accident. Besides their obvious value in accident prevention, competently conducted investigations can provide a number of additional benefits to include positive supervisor involvement, the control of rising worker&apos;s compensation costs and a measure of protection from civil/criminal proceedings. The paper describes such topics as MSHA minimum requirements, investigator selection and training, accident site procedures, witness interview techniques and the management review process. The reader is also presented with a number of information resources available through MSHA, the National Safety Council and other sources.

Jan 1, 1995

By Paul H. Rylund

Substantial priming was a considered necessity for proper initiation of ammonium nitrate-fuel oil mixes as ANFO began to carve its niche in the mining industry in the latter fifties. Heavy priming accompanied the introduction of prills and oil to many blasting operations, large charges of high explosives were commonly used at the bottom, top and frequent intervals through-out the column. As the quality of ammonium nitrate improved and operators became more experienced, primer costs began to diminish. Increased experimentation continued with reduced primer costs a main objective. Cast primers were introduced and became accepted as an excellent companion for ANFO. Although the trend toward larger diameter boreholes became increasingly popular, emphasis on lower and lower priming costs continued. A primer was simply required to produce any type of initiation within the ANFO column to be considered adequate. Suddenly ANFO priming had digressed from excessive to marginal. Early experimental data developed at "test site" and laboratory locations indicated that ANFO had a tendency to react inefficiently in the initiation region of the column unless substantially primed. This was evidenced by the presence of unstable reaction rates detected with newly developed detonation velocity measuring equipment. These 10" order or "transient" velocities were believed to originate because of inadequate primer strength or a primer diameter to column diameter mismatch. How-

Jan 1, 1972

By A. Adhikari, P. Tukkaraja, S. Jayaraman Sridharan

Shafts are critical components of the mine ventilation systems and contribute significantly to the mine ventilation pressure. Estimation of shaft pressure losses is an important aspect of mine ventilation planning and shaft frictional pressure losses are extensively studies. Shock losses contributed by shaft buntons are estimated using the interference factor model developed half a century ago. This study aims to develop a better performing prediction model for shaft buntons using state of the art experiment and numerical data, and machine learning techniques. Results show that the present prediction model is performing poorly, and the prediction performance can be improved by incorporating additional predictor variables. The Artificial Neural Network standardized Machine Learning model developed in this study is able to predict the shaft bunton shock loss with high accuracy (R2 = 0.956).

Jun 25, 2023

The Ernest Henry copper-gold project is located in North West Queensland, Australia and commenced production in late August 1997. Utilizing a philosophy of selecting the biggest proven equipment available Ernest Henry at full production ¥ill treat 9 Mtpa through a single grinding line over a 15 year mine life. 350.000 tonnes of concentrate a year will be produced, containing 95,000 tonnes of copper and 120,000 ounces of gold. The two mills recently commissioned at the Ernest Henry Copper/Gold Mine are a 10.4m x 5.1m (34 ft x 16.75 ft) SAG Mill and a 6.1m x 8.4m (20 ft x 27.5 ft) ball mill. The mills have a power draw of 11 MW (14745 hp) and 5.5 MW (7373 hp) respectively. While the SAG Mill is not the largest SAG Mill in the world, it is the largest shell-supported SAG Mill in the world. The Ernest Henry mills epitomize the new standard design of large grinding mills. The design was introduced more than 20 years ago and has been further developed from extensive experience with grinding mills, and the need to produce a design, which overcomes the recognized problems of large mills. The result is a design with the potential to be used for mills up to the largest for which machine tools can be found to fabricate and machine them, currently approximately 15m (48&apos;) overall diameter.

Jan 1, 1999