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By George Weinman

GEORGE WEINMAN: Our first group leader for the discussion, "Ups and Downs of Downsizing," wishes to remain anonymous. ANONYMOUS PRESENTER: When George and Jamie asked me to do this, I thought a while about what to say and went through several variations of what I’ll present today. I came up with the title "Ups and Downs of Downsizing." A lot of downsizing has occurred in all of our industries-mining in particular. While this downsizing has gone on there's no doubt that all of us produced more and more, probably with less and less people and less and less resources. But I contend that there's also a big downside associated with this. I disagree with a point made in the keynote presentation yesterday, the point being that vendors are bringing new technology to us. I can agree that the major changes associated with equipment and similar items are being brought to us by vendors. But I do contend that there's an awful lot that's getting away from us-especially if you factor in the integrated supply or the strategic alliance or the various and sundry related purchasing techniques. I contend that we are missing a lot of, let's call it, lesser technology; not major equipment changes, but different tools, different techniques for doing things, different left-handed widgets. The integrated suppliers, to some degree, are bringing this to us; but I am concerned about the small guy who comes up with a good idea but deals through integrated suppliers rather than having direct contact with plant people. They're probably going to go somewhere else and market their wares. That's what I'm hearing from a lot of smaller vendors. I also think that we are losing a lot of our knowledge base. Every time you shrink an organization somebody leaves. The bottom line: less people. When a person leaves-and I don't care who he or she is, be it the janitor who's cleaning the bathroom, the operator, the engineer-when that person leaves there's some knowledge that goes with that per- son. And sometimes that knowledge is quite valuable. I've worked more or less at the plant "low." I can't tell you how many excellent, viable projects have come from people who said, "Look here. There's a better way of doing this." And, you know, they were right. Now, maybe they didn't have the resources or the expertise to develop these ideas into full projects, but they had that basic idea. Someone may say, "Well, if we put a no. 6 skyhook here, so we can lift this particular pump without bringing a crane from 30 miles away ...." No. 6 skyhooks are a bit expensive, but what if we put together a little structural steel here or whatnot?

Jan 1, 1998

By D. M. Fritz

Environmental experts face large and rapidly-increasing volumes of raw data obtained from environmental monitoring stations. These professionals must compile and analyze the data in a systematic manner to cost-effectively understand and minimize the impacts of mining. The shift toward desktop computing, combined with the downsizing of company staffs, has now more than ever created a demand for a modern, PC-based application for the storage, retrieval, analysis and presentation of environmental data. This paper discusses the general requirements of such a system, and points out specific ways in which such industry-specific software can provide convenient and useful access to the data. The software used to illustrate these features is the HydroDat program, developed by Western Water Consultants, Inc.

Jan 1, 1996

By J. R. Allan

Loki Gold Corporation of Vancouver, B.C. is developing the Brewery Creek Mine, an open pit heap leach gold mine, 55 km East of Dawson City in Yukon, Canada. Mineable reserves are 17.1 million tonnes of ore grading 1.45 grams/tonne, containing 24.8 tonnes (797 000 oz) of gold. Ore processing will employ a cyanide heap leach using run of mine ore. Permitting this mine has drawn significant attention because the heap leach technology, while proven in other jurisdictions, has not been used in Yukon. Engineering design of the heap leach was similar to that for heaps in more temperate climates, with the added issues of permafrost and cold weather operations. Solution balance with seasonal placement of ore and year -round leaching requires very large pond capacity for spring thaw conditions.

Jan 1, 1996

By D. A. Swanson

Predicting when and at what rate seepage will occur from waste-rock facilities is becoming an integral part of permitting and closure at mines situated in dry climates. Such predictions require development of a conceptual framework that accurately describes how water will percolate through a waste-rock facility. Also needed is a detailed hydrological characterization of the waste-rock facility, including measurement of the hydraulic properties of the waste rock and any potential cover materials. This paper presents a conceptual framework describing unsaturated water flow in a waste-rock facility and describes methods for characterizing the hydrology of a waste-rock facility in a dry climate. The methods are designed to collect site-specific data to support accurate and defensible predictions of long-term seepage rates.

Jan 1, 1998

By A. E. Ketler

Optical smoke monitoring fills an important gap in ventilation and fire safety: namely monitoring of smoky, low temperature fires where little CO and heat are generated. Smoke monitoring also avoids the nuisance alarms due to diesel exhaust, battery chargers, blasting and welding. The smoke optical density (OD) fire alarm standard specified by MSHA presents an opportunity for improved safety. Experience of actual mine usage of the SmokeBoss*100 is reviewed, with particular regard to effectivity, maintenance and cost.

Jan 1, 1995

By Mark J. Zdunczyk

Short Mountain Silica mines the Clinch Formation, an orthoquartzite, for silica sand. The operation is located near Mooresburg, TN, about 80 km (50 miles) northeast of Knoxville. Short Mountain is a local geographic name given to an area of resistant sandstone (Fig. 1). The area is part of the Clinch Mountain system that extends from eastern Tennessee to southwestern Virginia. The thick sandstone unit is more technically called a quartz arenite (orthoquartzite) that forms most of the mountain. In 1980, a Knoxville resident brought the Clinch Formation - Short Mountain in particular - to the attention of the large silica-sand producers as a potential silica-sand mine. Working with a local contractor who owned several hundred acres on Short Mountain, the Knoxville resident contacted interested companies. Many silica companies reviewed the property including Ottawa Silica Co., Pennsylvania Glass Sand Co. (both now US Silica Co.),Unimin Corp.,The Morie Co. and others. AFG Industries was the main market for the glass sand product from this potential mine. It had two plants, both within trucking distance from the site. All the silica sand producing companies, however, declined to develop the site. A few years later, Unimin Corp. decided to drill and evaluate the deposit. From that evaluation, Unimin leased the property but later dropped it. The relatively limited market for the Short Mountain product as well as Unimin’s recent acquisition of Carolina Silica were reportedly instrumental in the company’s decision to let go of the lease. Several other companies-unrelated to the silica sand industry - looked at the site but no one was interested in developing it. In 1986, J.D. Nicewonder, owner of coal mines in Virginia and Kentucky, was approached to investigate the site. Nicewonder began to develop the site with the intent to produce glass sand to supply AFG Industries. In May 1988, the first shipment of sand was trucked to AFG Industries.

Jan 1, 1992

By Q. Xu

The adsorption behavior of gold in ammoniacal solutions on to activated carbon has been studied. The gold loading capacity of the activated carbon used in the system and the recovery efficiency by the adsorption were examined. The parameters affecting the adsorption of gold on to activated carbon included temperature, agitation speed, concentration of 'cation and anion as well as that of ammonia. It was found that the maximum gold loading on activated carbon used was about 10 kg of gold per ton of carbon. The recovery of gold by the adsorption from ammoniacal solutions was dependent upon the initial gold concentration in the solution. A recovery of 98% of gold was obtained on to the activated carbon under experimental conditions after 120 hour adsorption. It was also found that the initial adsorption rate was relatively fast compared to the whole period of the adsorption. The apparent activation energy for the adsorption was measured to be 15.8 kJ/mol. It was believed that the kinetics of gold adsorption on activated carbon was controlled by pore diffusion.

Jan 1, 1995

By J. K. Ross, K. O. Hoal, S. K. Appleby

Understanding ore variability is a key factor in the geometallurgical analysis of a deposit and is beneficial to process development and mine planning. Ore variability is a function of the mineralogy of a deposit, in terms of both ore and gangue minerals and their textural relationships. This study integrates optical microscopy and quantitative mineral analysis to characterize the mineralogy and texture from 13 samples from different lithologic units at the Bingham Canyon Mine. The analysis identified several parameters, such as modal mineralogy, alteration assemblages, distribution of mineral phases and alteration assemblages and microfracture and void space distribution. These parameters can have an impact on the materials’ behavior during processing. This study demonstrates that quantitative mineralogical analysis can provide detailed information for improved understanding of ore variability.

Jan 1, 2010

By Bernd Hagenah, Hans-Peter Vetsch, Eric Jones, Sean Cassady, Danielle Johnson, Petr Pospisil

There are a number of issues associated with freight trains in non-electrified tunnels that are fundamental during the planning and operation of a rail tunnel. During uphill operation, increased air temperatures at the air intake locations of diesel trains can reduce diesel motor efficiency (stalling/choking) and affect HVAC systems. Strong airflows can aggravate fire scenarios due to fanning or water-reactive cargo materials. This paper focuses on the impact of freight trains on tunnel safety concepts, strategies to overcome heat issues at locomotive air inlets and air quality in tunnels operating diesel trains.

Dec 1, 2022

By A. Haghighat, B. Lattimer

"Mine face ignition due to a high levels of methane is one of the most common fire incidents in underground coal mines. This work exams ignition scenarios in continuous miner headings. Depending on the magnitude of the ignition or resulting fire, the ventilation curtain in the continuous miner (CM) heading may be damaged or dislodged, affecting the ventilation into the area. A computational study was conducted to investigate the effects of different levels of damage to the ventilation curtain on the ventilation flow into the CM area. The computational fluid dynamics software Fire Dynamics Simulator (FDS), Version 6.0 was used to predict the conditions that develop due to a 200 kW fire in the coal mine face following a methane ignition with different levels of curtain damage. Smoke layer depth, temperatures and mass flow into the CM area were used to evaluate the impact of no damage to the curtain, partially dislodged curtain, and fully removed of the curtain. Partial removal of the curtain allowed more smoke to accumulate in the CM area and a reduction in ventilation into the CM area. With full removal of the curtain, the smoke accumulated through the entire depth of the CM area and flowed out the entrance to the CM area and the ventilation completely bypassed the region. INTRODUCTION Active working faces in underground coal mines are one the most hazardous locations in terms of fire events. According to Mine Safety and Health Administration (MSHA) data analysis, the highest number of non-fatal fire incidents was reported at mining faces, intersections and crosscut areas in comparison with other locations from 2000 to 2012. About 464 fires happened at active working faces from 2000 to 2012, most consisting of a methane ignition, in some cases followed by localized fire. These are high risk incidents due to the potential to raise float dust and damage ventilation systems, particularly auxiliary systems such as curtain or tubing. Depending on the magnitude of the ignition or fire, the ventilation curtain in the continuous miner (CM) area may be damaged or dislodged, affecting the ventilation into the area. Five computational fluid dynamics (CFD) scenarios were considered to investigate the smoke layer depth, temperature, visibility, mass flow rate, and the behavior of airflow in an entry with a continuous miner (CM) located in it. The state of the auxiliary ventilation was varied based on the assumption that as an ignition increases it magnitude it will affect ventilation curtain proportionally. Visibility and temperature along the height of the entry at different sections were investigated and the interface height at each section was determined. Also, the fresh air height was studied for tenability analysis in future. FDS, Version 6.0 was used to predict the conditions that develop due to a 200 kW fire on the coal mine face following a methane ignition with different levels of curtain damage. Smoke view software was used as the post processor to visualize and analyze methane fire behavior at the face. Most entry fires are reported as fuel-controlled fires as they are rarely restricted to air access (Ingason et al, 2014). The working face fire in the following models was assumed to be a fuel-controlled fire."

Jan 1, 2016

Paper and paperboard manufacturers need to quantify the carbon footprint and environmental impact of their products to satisfy market, social and government demands. Coated paper products contain minerals, such as kaolin and calcium carbonate, at significant levels; some coated paper grades have mineral contents as high as 45% by weight. Some uncoated paper has no mineral content, but most uncoated paper contains some mineral to improve appearance, process efficiency and cost. Super-calendared paper grades can contain levels of mineral up to 35% by weight. This paper describes how to calculate the carbon footprint of kaolin and calcium carbonate minerals used for white pigments. The carbon footprint of these minerals strongly correlates to the primary energy sources, final product form and energy used to calcine kaolin and lime. Kaolin and calcium carbonate pigments have a favorable impact on the carbon footprint of paper and paperboard products by directly substituting for fiber and by reducing the energy needed for paper making. Key words: Kaolin, Calcium carbonate, Paper production, Carbon footprint, Lifecycle analysis

Jan 1, 2010

By Sadatoshi Ohmori, Simin Zhai, Devini Abeyawardena

A road tunnel is planned to be constructed in soft, high overburden ground of around 600 m in Japan by using the center drift advancing method. The dodging effect and early ring closure of the center drift were expected to reduce the displacement and deformation of tunnel and promote safe construction. The measurement result during construction was analyzed and those effects, which the displacement and deformation after the widening excavation decreased and its effect increased as the center drift radius increased, were confirmed by numerical analysis. Also, the effect of the early closure of center drift after widening excavation did not have much effect.

Jun 23, 2024

By Gerhardt A. Bennewitz

The mechanism shown here (Fig. 1) may not be all that it appears to be. To many of you it may look like a hopper car, a thing of mobility, in which you would ship coal, ores, limestone, or other bulk materials. It is approximately 50 feet long, 12 feet high, and can be placed on tracks which are on approximate 14 foot centers. But far too often in the past, and all too often today, this mechanism has been made to serve as an immobile storage box, with its primary role -- the transportation of products, seemingly incidental to the storage function. Our engineering training teaches us to conserve resources, despite some of the popular and misconceived philosophies being advanced these days. Those of you who work for companies with traffic departments know that they are always striving to reduce the price which is paid to move your mine products. Today, let's consider and analyze the ways in which the cost of transporting your mine products might be reduced, based on particular reference to coal. Bear in mind that in this context, cost and price are not necessarily synonymous. Until a few years ago, most coal and other bulk materials handled by railroads moved under standard tariff rules. These rules, which still exist today, provided transportation vehicles (railroad cars) for extended periods at no added price to the shipper or receiver. "Normal" free time rules would permit a car to be held for a maximum of 48 hours without charge; however, in the case of coal, there is a rule which, subject to liberal rules as to the

Jan 1, 1972

By R. F. Harig

Designing an underground nuclear waste repository is a complex process. Although many decisions are involved before the design is complete, the first three--what the target horizon is, what the underground boundary is, and where the entry point will be located--are important because they establish the basis for the entire repository design. Even more important than these decisions, however, is the data on which the decisions are based. Because the current data are limited, an aggressive data gathering program is needed during the next design phase to augment information about the intricate interplay among all facets of the repository design and the geologic medium in which the proposed repository is to be developed. Although unique to modern engineering enterprises, the challenges involved in designing a repository in the unsaturated zone are within current technology and engineering practices.

Jan 1, 1991

By M. Lotfi

The criteria for evaluating equipment operator performance were identified as the changes in reaction time, the changes in physiological responses, and the changes in subjective reporting of stress. Data were collected while the Subjects operated a front-end loader simulator. This report out-lines the components and the tasks generated by the simulator. It explains the simple and basic assumptions underlying the design of the simulator and the methods of data collection. Improvements that can facilitate the collection of data, including the connection of the simulator to a portable personal computer for on site use are discussed. Statistical analysis of data showed significant deterioration in performance. The report concludes that operator performance can be measured and improved. This report shows that the operator tasks can be simulated by means of simple simulators, the complexity of which is determined by the availability of funds and the area of interest of the investigator.

Jan 1, 1989

By John Litz

The term "refractory gold ores" refers to a wide number of ore types which are not readily amenable to direct cyanidation. A number of processes have been used commercially, and a number of others have been proposed and in many cases pilot tested. The selection of the appropriate process for an ore should not be arbitrary. Ore grade may preclude some processes, but a good understanding of the ore mineralogy can guide the selection. Many present gold operations and many potential gold operations have faced or are facing problems with refractory gold mineralization. We at Hazen Research have had the opportunity to perform bench testwork and in some cases, pilot plant testing on a number of refractory ores. The data included in this paper are excerpted from the testing of fifteen ores which cover a wide range of mineralogical compositions. This paper is not intended to be a treatise on the processing of refractory gold ores. In many of these gold projects, not all of the standard process alternatives were evaluated, nor was adequate mineralogical work performed. Such is the dilemma of contract research. "If I believe that I don't need it, why should I pay to have it done." The intent of this presentation, therefore, is to show how different ores respond to the various processes, and to demonstrate that one must have an open mind when developing a process for a specific refractory gold ore.

Jan 1, 1998

By J. Urosek

Since the promulgation of the Mine Safety and Heath Administration?s (MSHA?s) Final Rule on mine seals (30 CFR § 75.335(b)), which became effective on October 20, 2008, many seal designs have been approved by MSHA and constructed by the mining industry. Since the effective date of the Final Rule, several issues on the design, construction, and/or inspection of seals have been brought to the attention of MSHA. Several such issues discussed in this paper include; the directional, design-load criteria required by MSHA for 50-psi seals, 120-psi seals, and greater-than-120-psi seals; the presence of fireclay in the surrounding strata where a mine seal is to be built; the measurement of convergence of the mine opening in which a seal has been constructed; where gob-isolation seals can be used; and the importance of periodic inspection of seals.

Jan 1, 2010

By M. L. Leming

The mechanisms of Alkali-Silica Reactivity (ASR) are briefly reviewed, test methods are examined, and typical specifications are discussed. In addition, views on responsibility of the aggregate supplier regarding specifications are presented.

Jan 1, 1995

By D. H. Dvorak

Two pilot-scale biological reactor systems were installed to treat metal-contaminated water. The reactors consisted of barrels and tanks filled with spent mushroom compost, within which bacterial sulfate reduction became established. Concentrations of Fe, Zn, Mn, Ni, and Cd were lowered by over 95% as these metals were precipitated as insoluble sulfides by reaction with bacterially generated H2S. The chemistry of the reactor systems is examined, and opportunities for maximizing their metal-retaining and alkalinity-generating potentials are discussed.

Jan 1, 1991

By C. S. Harman, C. A. Enright, J. F. Brune

"The mining environment presents challenging and complex situations for the application of medical care. The combination of remote locations, difficult access and longer response times may create an increase in morbidity and mortality in the event of serious accidents. The U.S Mine Safety and Health Administration (MSHA) has only minimal requirements of first aid training for mine workers. For mine rescue team members, MSHA requires medical training at the Emergency Medical Responder (EMR) level, as only prescribed by mine rescue contest rules. This paper examines, based on mine accident statistical information, whether a higher level of medical training, for example at the Emergency Medical Technician (EMT) or at the Advanced Life Support (ALS) level can better address injuries most commonly disabling or leading to the death of miners in the United States. BACKGROUND Prehospital emergency medical care for the sick and injured has evolved considerably from first inception. Ambulances used to be staffed by persons with little training and equipment and prehospital care was focused largely on the rapid transport of the injured person to a hospital and. The modern prehospital care model was initially developed in military applications, where medics were responsible for some treatment on the battlefield and rapid transport to the care of a physician. In 1965, the National Academy of Sciences and National Research Council Committees on Trauma and Shock published Accidental Death and Disability: The Neglected Disease of Modern Society (National Research Council Committees on Trauma and Shock, 1966). This white paper laid out the consequences of the insufficiency of the Emergency Medical System (EMS) in the United States at that time. According to this paper, in 1965, 107,000 people were killed from accidental injury, with another 400,000 injured with permanent disability. The authors estimated that approximately 50% of ambulance services were provided by local morticians that were not capable of rendering advanced life support. The paper states that, based on experiences in the Vietnam war, seriously wounded soldiers had a better chance of survival in the battle field compared to traffic accident victims with similar traumatic injuries because the military was capable of providing first aid and efficient transportation to emergency care facilities. The white paper states that death rates from battle injuries declined significantly from 8% in World War I to 2% in Vietnam. The publication of this white paper is credited for the broad evolution and rapid advance of the civilian EMS system after 1965. It eventually lead to the creation of the National Highway Transportation Safety Administration (NHTSA) National Standard Curricula (NSC) for emergency medical care in 1985. Training, and therefore required skill and knowledge for prehospital emergency care has continued to grow to reach the current standard."

Jan 1, 2016