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By Harvey W. Parker

Our industry has developed to the skilled, experienced and productive industry that we now enjoy as a result of the visions of great engineers throughout history, but, in particular for their visions in the last 1 centuries. Unfortunately for our forefathers, the technology lagged so far behind that these exceptional visions could not be realized for decades, sometimes for a century. All that has changed in recent time and many bold and visionary projects can now be constructed and operated because of dramatic advances in technology. Before, say, 1950, tunnel technology developed very slowly. However, technology is now developing at such a fast rate that planners and decision makers are challenged to stay ahead. Moreover, new technology will develop during the lifetime of any project that can dramatically improve under-ground space projects. One of the best examples of this technological advancement is that of closed-face TBMs which now make tunneling feasible in previously impossible ground conditions. Since it usually takes a decade or more to plan, overcome environmental and political issues, construct, and put into service major projects, planners and designers are challenged by the changes in technology that occurs during the long time span of planning and construction. This is particularly true of large infrastructure projects such as transportation, water and wastewater systems and other major underground schemes. Also, since the serviceable life of many of these tunnels is often over one century, planners must consider not only lessons learned from the past but also what new concepts and innovations may develop over an extremely long time. These and other issues create a great challenge to planners and illustrate the great importance of careful but creative vision and flexibility during planning of long-term tunnel and underground space projects.

Jan 1, 2008

By H. E. Hirsch

Propelled by the invention of the transistor at Bell Laboratories, germanium's unique properties have advanced our electronic world by many years. Germanium has found major uses in infrared optics, fiber optics and a revised vigor as a catalyst for PET plastic production. Other advanced applications are in various stages of development. The solid state electronics industry has been the driving force behind the accelerating demand for gallium since the late sixties. Past developments of substrates for light emitting diodes, lasers and magnetic bubble memories are paling in view of the current excitement over the use of semi-insulating gallium arsenide for high performance integrated circuits. This application requires gallium metal and gallium compounds of extraordinary purity.

Jan 1, 1986

By Robert R. Beebe

At first glance, mineral processing on an industrial scale might seem entirely in the realm of macro-engineering, with large machines operating on minerals and rocks to achieve size reduction, classification, chemical treatment, separation and dewatering. These operations must be conducted on a large scale to be of practical interest. But the machines and processes may not be designed and operated to take fullest advantage of micro-engineering factors. At the same time, idealized designs based solely on micro-engineering research may require adjustments to gain the desired results in the larger scale, operational context. Using micro-engineering research in this way allows the design and implementation of more efficient versions of the machines and processes currently used, while aiding the revolutionary developments unlikely to come from macro-engineered, trial-and-error solutions. Thus, from an industrial viewpoint, micro- and macro-engineering are complementary functions.

Jan 1, 1992

By H. K. Conn

This paper discusses briefly the evaluation of chrysotile asbestos deposits in ultramafic rocks. Such deposits are limited to serpentinized peridotite and/or dunites. The purpose of any evaluation is to determine whether a deposit contains sufficient ore mineral to justify profitable exploitation. Dimensions of a mineral zone are established by conventional methods, such as mapping, ground magnetic surveys, diamond drilling or underground exploration. The value of the contained asbestos fibre Is dependent on numerous physical properties such as fibre length, strength, flexibility, as well as the actual amount of fibre present. The determination of grade is difficult. The Quebec Standard Test (Q.S.T.) is used to grade fibre according to the proportionate lengths of fibre present. A method of visual vein counting allows calculation of an approximate percent fibre together with a simulated Q.S.T. Various drilling methods are discussed, diamond drilling is favored. Bulk sampling is required to determine fibre quality. Correlation of visual techniques and laboratory methods are often difficult. Reasons for any variance are discussed. Underground bulk sampling of most potential ore zones is strongly recommended to confirm the viability of the property. Evaluation of slip fibre deposits requires greater reliance on laboratory testing as visual methods are difficult to apply. Cross fibre has greater inherent strength.

Jan 1, 1971

By Terry M. Hertel

The chemistry of waters processed by Acid Rock Drainage water treatment plants can affect the Total Suspended Solids quality of the plant effluents. The sulfate ions in the ARD water will combine with the calcium ions from the lime that is used to adjust pH to form calcium sulfate. When the sulfate content of the waters to be treated is greater than about 1400 parts per mil­lion, the resulting calcium sulfate concentration will be approx­imately 2100 parts per million. This concentration is above the saturation point for calcium sulfate, and the salt will drop out of solution until the concentration falls below the saturation point. This "salting" phenomenon affects the total suspended solids of the treatment plant effluents by virtue of the fact that the salts will report to the filtration apparatus used for the analy­sis. This scenario is exacerbated as an effluent sample ages. Zortman Mining's water treatment plant effluent was being affected by "salting" during the spring and summer of 1995, and it seemed as though the effluents were exceeding the TSS lim­its; for no obvious reason. A testing program was initiated to verify an observation that "salting' was taking place. Treatment plant samples were collected and allowed to age, with TSS analyses being performed every day that the samples aged. Synthetic solutions were also prepared to study the "salting" phenomenon.

Jan 1, 1996

By David E. Siskind

The Bureau of Mines has studied the problem of cracking in residential structure walls from vibrations produced by blasting in surface mines. Direct observations were made of blasting damage consisting primarily of cosmetic cracking in plaster and gypsum board walls. Measurements of structure response and also application of the response spectra analysis single-degree-of-freedom model were used to quantify the frequency dependence of the safe level criteria. An overall summary analysis was performed using the new Bureau of Mines damage observations and data obtained from nine previous studies, including the three analyzed earlier by the BuMines for Bulletin 656, published in 1971. Separate analysis of the high- and low-frequency damage cases, structural response, and two types of construction resulted in the establishment of safe vibration levels ranging from 12 mm/sec to 50 mm/sec (0.5 in/sec to 2.0 in/sec).

Jan 1, 1980

By E. Tarshizi

Research was conducted to develop a simulation and animation model for an aggregate (sand and gravel) mine operation. This model can assist the mine engineers to investigate and consider the various options of haulage systems which are critical for the mine operation productivity. Discrete-event system simulation studies can be used for the typical haulage issues that mining engineers are often faced with: using truck fleet haulage, conveyor belts, or a combination of both. The simulation has identified some strengths and weaknesses in the current loading and hauling fleet of the mine, and has resulted in some suggestions for improving the system. The simulation includes animation of the operation. Animation is needed to enhance the benefit of any mine simulation model. By combining the visual power of animation with a mine simulation, a complete picture of the mine system is obtained and displayed. The mine is modeled and animated using GPSS/H® and PROOF Professional®, both of which have shown great applicability in discrete mining simulation projects.

Feb 23, 2014

By Gregg W. Davidson, J. Andrew McGlenn, Frank Huber

The Second Narrows Water Supply Tunnel will ensure system reliability in the event of a major earthquake and increase the Greater Vancouver Water District’s capacity to meet the long-term needs of a growing population. The tunnel will be 1,100 m long and 6.5 m in diameter (3,610 LF × 21.3 ft), constructed under Burrard Inlet between North Vancouver and Burnaby in British Columbia. It will be excavated through mixed ground conditions under high groundwater pressure, using a slurry TBM, between a 72 m (236 ft) deep shaft in soil and a 110 m (361 ft) deep shaft in rock. The completed tunnel will accommodate three large-diameter water mains that will be installed as part of the tunnel contract. This paper presents the project from design and contractor procurement, into the current construction stage describing some of the unique challenges encountered during the project development to date.

Jun 13, 2021

By Andrew N. Peterson

US mine operators frequently fail to investigate more cost effective and productive bulk material handling systems because surface mines seem to lend themselves to truck ore haulage. In this country, as a result, use of conveyors to move heavy loads from mine to process facilities has been minimized, if not actually neglected. In contrast, there are more than 50 conveyorized surface mines in successful operation around the world. These mine operators have learned that properly applied conveyorized systems can offer major savings in capital and operating costs, which contribute to improved profits when combined with other proven mining technologies. Growing acceptance and application of conveyorized bulk material handling in surface mines also points up how unique each mine is and how careful planning contributes to maximum mine effectiveness. Because of these differences, mining executives and technical and operating staffs need to develop an understanding of three factors in applying conveyorized bulk material handling in surface mines: • Why each mine will benefit from the type of automation permitted by conveyorized operation, •What kind of equipment is available, and • What applications most effectively demonstrate the first two factors in action - hauling either ore or waste. The conveyorized systems considered in this presentation have production rates from 0.5-2.7 kt/h (500-3,000 stph). Worldwide, these systems have been operating since the early 1960s. Advantages of Conveyors Why do you want conveyorized bulk material handling? First, it almost always provides lower operating and maintenance costs. Second, it frequently requires lower initial capital costs and almost always requires lower capital costs over the life of the surface mine. Third, it provides comparable operating availability, and finally, it frequently gives comparable operating flexibility - depending on the mine plan. Cost avoidance can be accomplished with modern production methods. These, in turn, permit increased productivity and reduced operating costs such as those for energy, maintenance, and manpower. It has been demonstrated in European surface mines and elsewhere, that conveyor systems frequently require lower initial costs than does truck haulage. Almost always such operations require lower capital costs over the mine life. Those costs include the continual addition of haulage trucks to both accommodate the increasingly difficult haulage routes and fulfill replacement requirements when trucks wear out. Conveyor systems handling ore in numerous large crushing and port facilities, which have operated since the early 1950s, have clearly demonstrated a useful conveyor life of more than 25 years. In contrast, off-highway trucks have life spans of six to eight years. The following examples illustrate comparative capital costs to purchase conveyor systems and comparable truck haulage units. Example 1 The ore haulage route from point A to point B is level and 610m (2,000 ft) long. The material weighs 1.8 t/m3 (110 lbs per cu ft) and must be transported at a rate of 1.8 kt/h (2,000 stph). The installed capital costs to provide a properly designed conveyor that will transport the described material from point A to B is about $450,000. The capital cost to purchase three 77-t (85-st) off-highway trucks and one spare truck - which would provide equivalent capacity - would be about $1.2 million. The truck cost estimate is based on a 6 min. or 771 kt/h (850 stph) truck cycle time. Truck efficiency is estimated at 0.8. Each 77-t (85-st) truck would have an actual haulage rate of 617 kt/h (680 stph). Therefore, three trucks would be necessary to transport the designated tonnage of 1.8 kt/h (2,000 stph). A movable crushing plant would be located at point A for the conveyors and a permanent crushing plant at point B for the truck haulage system. Capital costs for these primary crushing plants were not included in the calculations for either system because the capital costs are frequently comparable. Example 2 The transport route from point A to point B is 610 m (2,000 ft) horizontally and 122 m (400 ft) vertically - on a 20% grade (Fig. 1). The material weighs 1.8 t/m3 (110 lbs per cu ft) and must be moved at a rate of 1.8 kt/h (2,000 stph).

Jan 6, 1983

By G. Trusler, P. Dama, C. Buckley, C. Jänisch

In the 1990s, Cleaner Production (CP) approaches were successfully introduced to a number of industrial sectors in South Africa. Building on this success, the South African Water Research Commission has commissioned a 3-year study to investigate the use of CP and its related set of environmental assessment and management tools in the mining industry. A scoping study is being carried out on the current knowledge of CP approaches being used in the industry, as well as the proactive and preventative measures being undertaken. One of the significant findings of the scoping study is that distinct differences exist between the larger global companies and the smaller local companies. Being a water research project a key focus area of the project is to reduce the impacts related to mining on the South African water resources. Some of the significant water related threats identified include acid mine drainage, the shortage of the resource and the effects of inter-mine flow.

Jan 1, 2005

By H. Reed

The precious metal mining industry in Nevada handles and generates a certain amount of hazardous materials and waste on a regular basis. These products range from processing material additives to wastes from laboratory testing, heap leaching, and hydrocarbon treatment and disposal. The volume of materials and wastes is dependent upon the amount of ore processed. Handling, treatment and disposal is dependent on the type of material handled and the waste generated. Owing to the health and safety concerns and due to the existing regulations that control handling and disposal of hazardous materials and wastes, the mining industry is obligated to comply with all applicable requirements for proper handling of these products. Plus, in an effort to minimize any impacts from this effort, the industry is continually looking for alternative methods to accomplish these requirements and to also minimize costs. This paper will discuss the general, and in some cases the specific conditions, by which the industry is coping with the issue and efforts to minimize any impacts from handling, treatment and disposal for hazardous materials and wastes. The subject of compliance with the Toxic Release Inventory (TRI) requirements and bio-treatment of wastes and other technologies will be discussed.

Jan 1, 2001

By H. Sevim

Belt network simulators developed in the last two decades are reviewed. Critical parameters in belt network design are identified, and the capabilities of belt simulators in providing values of these parameters are investigated. An alternative design model that optimizes values of the critical parameters is introduced. To illustrate the capabilities of the alternative model, a real life case is treated and the outcomes are discussed.

Jan 1, 1990

The current understanding of the mechanics of rock fracturing during smooth blasting is largely empirical and qualitative due to an inability to model the dynamic process at the fundamental level. In order to overcome this difficulty, a numerical simulation of smooth blasting is performed using the Dynamic Lattice Network Model. This model is capable of simulating material inhomogeneities and the dynamic evolution of fragmentation at the micromechanical level. In this study, smooth blasting techniques are numerically analyzed to characterize the development of the damage rock zone during explosive fracturing.

Jan 1, 1995

By Swan. J. D.

Repairing and replacing equipment damaged by corrosion and abrasion is a major cost throughout industry, especially in the coal mining industry. Careful study of corrosion and abrasion, and their causes and effects, often leads to the selection of alternative materials which can provide economies. What, actually, are corrosion and abrasion and how do they contribute to the cost of operating a coal-preparation plant? Furthermore, what can be done to alleviate corrosion and abrasion problems and thereby reduce operating costs? These questions will be answered in the following discussion, which will describe the destructive action of corrosion and abrasion and give several methods for controlling corrosion and abrasion losses, These methods include the substitution of stainless steel for carbon steel, the use of corrosion inhibitors, and the use of design to eliminate corrosion and abrasion. Examples will be given illustrating the benefits that have resulted in plant tests when these methods of controlling corrosion and abrasion were used.

Jan 1, 1970

By D. R. Willmer

An understanding of how health and safety management systems (HSMS) reduce worksite injuries, illnesses and fatalities may be gained in studying the behaviors of health and safety leaders. These leaders bear the accountability for identifying, understanding and managing the risks of a mining operation. More importantly, they have to transfer this knowledge of perception, recognition and response to risks in the mining environment to their workers. The leaders’ efforts to build and maintain a mining operation’s workforce that consistently executes safe work practices may be captured through more than just lagging indicators of health and safety performance. This exploratory study interviewed six leaders in occupations such as site-level safety supervisors, mine superintendents and/or general managers at surface and underground stone, sand and gravel and metal/nonmetal mine sites throughout the United States, with employee populations ranging from 40 to 175. In exploring leaders’ perspectives on how they systematically manage health and safety, examples such as approaches to task training, handling near-miss incidents, identifying future leaders and providing workers with feedback offer insights into how leaders translate their knowledge and management of site-level risks to others.

Jan 1, 2018

By D. R. Willmer

An understanding of how health and safety management systems (HSMS) reduce worksite injuries, illnesses and fatalities may be gained in studying the behaviors of health and safety leaders. These leaders bear the accountability for identifying, understanding and managing the risks of a mining operation. More importantly, they have to transfer this knowledge of perception, recognition and response to risks in the mining environment to their workers. The leaders’ efforts to build and maintain a mining operation’s workforce that consistently executes safe work practices may be captured through more than just lagging indicators of health and safety performance. This exploratory study interviewed six leaders in occupations such as site-level safety supervisors, mine superintendents and/or general managers at surface and underground stone, sand and gravel and metal/nonmetal mine sites throughout the United States, with employee populations ranging from 40 to 175. In exploring leaders’ perspectives on how they systematically manage health and safety, examples such as approaches to task training, handling near-miss incidents, identifying future leaders and providing workers with feedback offer insights into how leaders translate their knowledge and management of site-level risks to others.

Jan 1, 2017

By Jeremy Maurer, Duah Philip, Awuah-Offei Kwame, Donya Otarod

Land use impact assessment for mining is time- consuming and expensive. Because of mining’s impact on biodiversity, land use assessment methods that evaluate biodiversity are important for mining land use impact assessments. Remote sensing, in particular satellite multispectral sensing platforms such as Sentinel‑2 and the Landsat mission series, have been used to assess and quantify biodiversity through proxy variables such as NDVI (Peña-Lara et al., 2022). The objective of this paper is to present results of a comparative study of land use and biodiversity based on multispectral satellite observations and production data from copper and cobalt mining in the Democratic Republic of Congo. We quantify the relationship between different spectral bands and vegetative indices and the production data provided by the mining companies and measure correlations. The results suggest that remote sensing could be a cost- effective means of assessing biodiversity impacts of mining.

Feb 1, 2025

By S. K. Kawatra, V. Claremboux, S. Valluri

Carbon dioxide capture from coal-fired power plant flue gas and subsequent sequestration is expected to play a vital role in mitigating global climate change. To meet the growing need for CO2 capture Technology, Michigan Technological University is researching CO2 capture and Utilization. We have successfully converted CO2 into oxalic acid using an electrochemical approach. If oxalic acid can be produced in bulk from CO2, it can be used to leach rare earth minerals at low cost. Electrochemical reduction of CO2 to hydrocarbons and other chemicals is a complex multistep reaction with adsorbed intermediates. The exact reaction mechanisms leading to various products are not clear from the literature to date and will likely change over the range of conditions like pH, electrode potential, electrolyte medium, catalyst, etc. In this paper, we will present an idea of how the factors mentioned above will effect the electrochemical reduction of CO2 to Oxalic acid. INTRODUCTION. CO2 is thermodynamically quite stable, as shown by its highly negative heat of formation. Thus, it is expected that the formation of any useful chemical from CO2 will require the input of at least as much energy as geological sequestration. However, to be more effective the resulting economic value of the chemical need only pass the cost of the additional energy required beyond geological sequestration. This lends itself to two extremes: one where the quantity of energy required is low and one where the economic value of the additional energy is low. It is expected that CO2 can be reduced via electrolysis to several compounds. Of particular interest are formic acid, oxalic acid, methanol, ethanol, formaldehyde, and carbon monoxide (as a component to syn-gas). These chemicals have been reported as electrolytic products previously in literature and have considerable potential for application. EXPERIMENTAL Electrocatalytic Production of Oxalate from CO2 We are using membrane electrolysis cell to produce oxalate from CO2. A membrane electrolysis cell is a 2-chamber electrolysis cell where the chambers are separated by a selectively permeable membrane. To produce oxalate, a cation exchange membrane (which selectively exchanges cations) was used. Previous literature suggests that in the cathode chamber an organic electrolyte, such as tetraethylammonium perchlorate or tetraethylammonium bromide in dimethylformamide, are preferred3. In the anode chamber, a sodium hydroxide solution water is used. Carbon dioxide is then bubbled into the cathode chamber as a current is applied.

Jan 1, 2019

By V. K. Gupta

A detailed experimental study of the variations in grinding rate with particle size, particle load, ball diameter, ball load, mill diameter, and mill speed was carried out for a soft cement clinker and a hard cement clinker. The effects of the ball diameter, ball load and particle load were observed to be material (hardness) independent, and those of the particle size, mill diameter and mill speed to be material dependent. A sharp change in the grinding behavior was observed for both the clinkers at about 150 µm size. Below this critical size: (i) the hardness difference between the two clinkers became insignificant, (ii) variation in the grinding rate with particle size became markedly more pronounced, and (iii) mill speed had little or no effect on grinding rate. The importance of these results in the context of process optimization and control is discussed.

Jan 1, 1987

By P. A. Plunkert, D. E. Morse, L. McCartan, S. F. Sibley

Following the recession of 2001, restrained consumer spending, declines in domestic manufacturing and industrial output, and increased unemployment led to a lack-luster year in the domestic economy. In 2002, the U.S. real gross domestic product (GPD) grew only 2.4%. Significant production declines in the U.S. metals industry were registered by copper, lead and zinc producers. Steel producers, despite a slight improvement in shipments, continued to face strong foreign competition, higher energy costs and lower prices for their products. Homebuilding and other domestic construction sectors— major consumers of nonmetallic mineral products such as cement, brick, glass and stone — remained strong enough to help raise the output of industrial mineral materials slightly above 2001 levels. A strong U.S. dollar relative to other national currencies continued to weaken the competitive stance of U.S. metal and non-metal mineral materials companies alike against foreign producers in markets at home and abroad.

Jan 1, 2003