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By Jurij Karlovšek, Wolfgang Angerer, Vojtech Ernst Gall, Jacob Grasmick

The International Tunneling Association (ITA) Working Group (WG) 22 “Information Modelling in Tunneling” has developed a guideline for the implementation of Building Information Modeling (BIM) concepts for Bored Tunneling Projects. The guideline primarily covers the use of BIM during the conceptual and delivery phases of a project. It provides Owners with an introduction to BIM, an overview of the current capabilities of BIM, and a guide for implementation for a Bored Tunnel. The document will be officially published at the World Tunnel Congress (WTC) in Copenhagen in 2022. This paper describes the need for the guideline and provides a preview of its contents.

Dec 1, 2022

By Enrique Levy

The publication from which this paper was abstracted is the first at-tempt to correlate all the metallogenic deta compiled by the author for the preparation of the 1:2,000,000 Metallogenic Map of Central America. It is not a treaty of metallogenic theories but rather a careful effort to postulate metallogenic provinces and epochs with the intention to stimulate other geologists and mining companies familiar with the area to criticize and improve on the ideas proposed. The sole purpose being to find new mineral deposits for the betterment of our people.

Jan 1, 1971

By Herman Gill, Dani Delaloye, Madelyn Rubin

The Foothill Tunnel is a remote 16-mile-long untreated drinking water tunnel in the San Francisco Public Utilities Commission’s (SFPUC) Hetch Hetchy Water and Power (HHWP) system. The 14-foot horseshoe shaped tunnel, constructed in the 1920s, is lined intermittently with concrete over approximately 53% of its length, with the balance being unlined rock. After detailed planning, in January of 2020 Mott MacDonald and HHWP staff completed a visual inspection and documented the condition of the tunnel with electronic data collection, photographs, and video with audio recording. The result was a comprehensive condition assessment that identified key areas of the tunnel to monitor.

Jun 13, 2021

By CK Tsang, Jack Muir, Dharman Gersch, Joshua Barry

Correct face pressure is critical to safe operation of a closed face TBM. If inadequate face pressure is applied, this will lead to excessive ground movement, and may result in collapse of the tunnel face. Face pressure calculations are performed manually every few meters along the tunnel alignment. With the application of a 3D ground model, ground profile information can be extracted for automatic computation. This will significantly improve the efficiency and accuracy and is adaptable to changes in design parameters. This paper will discuss the development of automatic computation techniques in extracting information from a 3D ground model.

Jun 13, 2021

By Julia Herhold

The demand for sustainable and profitable/efficient projects within the tunneling and other underground engineering sectors grows rapidly. Construction tasks play a key role within the project conduction, whether as primary (tunneling), secondary (e.g., mine securing) or tertiary processes (e.g., workshops). The construction tasks of primary processes create the main structures, such as tunnels, which resemble the main project goal. For the secondary and tertiary processes, the purpose of the task shifts. The main goal is to provide structures, such as the securing of the cavity and workshops, that enable the project and enhance the efficiency of the primary conduction underground. To plan and optimize the conduction of construction tasks underground, whether they are identified as primary, secondary or tertiary tasks, the work preparation can be used. This method, known from the above ground construction, can be adapted and used underground. The approach of a digital work preparation tool combines, connects and adapts the main tasks “choice of procedure,” “logistics” and “site planning.” In addition, the digital tool is connected with digital models (construction, site, surroundings). With the adaption and forward projection of the work preparation, underground constructions (e.g., tunneling) can provide a more sustainable and efficient outcome.

Jun 13, 2023

By I. Cameron-Clarke

This paper describes the design of a wellfield to provide a water supply for a new mine in southern Africa. A hydrogeological investigation was conducted that included the drilling and test pumping of eight wells located within a highly jointed pyroxenite aquifer. The wellfield was designed using a simple probabilistic analysis. This approach allowed the variability of the aquifer parameters to be taken into account. A risk assessment analysis was then carried out to evaluate the level of assurance that a reliable water supply could be provided by the wellfield. The analysis was also used to assess the effects of supplementing the water supply by pumping from nearby flooded workings.

Jan 1, 1992

By Michael Roach

"There’s a bit of confusion and misinformation in the tunneling and underground construction industry regarding contractor joint ventures. If it was all so clear I would not have been "asked" to write this article. For those of us on the contractors’ side of the fence, joint venture business relationships have been a part of life for a long time. But even for contractors, there can be a bit of confusion, and it normally begins on bid day.How often have you received bid results and wondered (out loud, usually), "Who the hell are the Lake Mead Intake Constructors"? or the "Regional Connector Constructors"? Once you get past the name, you see that there is nothing behind Oz’s curtain other than a couple of contractors bidding and building work in an attempt to make a profit. So take a few minutes to read the rest of this, and I’ll do my best to dispel a few mythWhat is a joint venture?In some form or fashion, joint ventures are as old as industry itself. In the United States, some of the earliest (and largest) joint ventures involved the railroads and oil companies in the late 1800s. In the United States’ underground construction industry, joint venture names such as, Healy-Greenfield, Green and Winston, Gates & Fox and Walsh, Shea-Ball, Kenny-Paschen and S&M-Traylor bring back memories of successful joint ventures that operated over many projects.There are nearly as many definitions for joint ventures (JVs) as there are attorneys. A short and simple definition is, "an association of two or more companies engaged in a singular, for-profit business enterprise without actual partnership or incorporation." That’s it. Two or more contractors decide to partner up for one or more projects. One benefit of the JV relationship is that the partners typically do not need to file incorporation documents, or articles of organization within the state where they intend to operate. So it is a relatively easy business arrangement to pull together. Other benefits of the JV arrangement include: • Oportunities to gain new expertise and capacity.• The ability for firms to move into new geographic markets.• JV agreements are not long-term commitments.• Sharing of financial support for a project.• Sharing of financial risks within a project. between the partners.• Can complicate dispute resolutions with the owner and between partners"

Jan 1, 2014

By Dan Witkowsky

In an increasingly environmentally conscious world, mining's importance to society has often been misunderstood and even maligned by the public. Extreme and impractical ideas have often been presented to children because of the lack of accurate, timely resource materials available to educators. In the late 1960s. two mining engineers, S.P. "Pi" Warren and C.L. "Lindy" Barker, became aware of this situation. They proposed to develop a summer field course to provide a factual overview of the minerals industry for teachers. The pair believed that teachers could become better informed to educate students, and future generations, about mining. These two Colorado Mining Association (CMA) members felt that such a course could reduce much of the misunderstanding about this vital industry. This could be done by providing a balanced perspective of mining, not only for kindergarten-through-grade-12 teachers, but also for the students they would be teaching during their careers. Students who better understood the minerals industry could better formulate an unbiased view of it. The course would seek recognized authorities from industry, academia and government who would lecture in their respective fields of expertise. The course would provide a total concept of the coal, aggregate, metals and industrial minerals industries. It would include geology, geophysics, exploration, mining, processing, marketing, product applications, economic, mining history, careers, and environmental responsiblity. When possible, site visits would permit educators to view operations and to meet the men and women who are industry leaders. Teachers would pay a small tuition fee. The balance of the program expenses for each teacher would be paid through scholarships provided by industry and individuals. The "total concept" idea obtained the support of the minerals industry. The support of CMA's Education Committee and the Colorado School of Mines (CSM) was obtained in 1968. Colorado's Commission on Higher Education approved teacher recertification credits through CSM's Office of Special Progams and Continuing Education for those successfully completing the program. The first six-week series of classes presenting the total concept of the indus¬try was held at CSM in 1969. In 1977, the CMA Education Foundation Inc. (CMAEF) was established as a Colorado nonprofit corporation. The "Total Concept of the Mining Industry" (Total Concept) course was placed under its sponsorship. CMAEF is dedicated toward this continuing education program (Table 1). In 1994, the course was streamlined to four-weeks for six hours recertification credit.

Jan 1, 1997

By K. Mohamed, G. Rashed

A conventional mechanical anchor bolt consists of a smooth bar threaded at the anchor end, with a conical wedge, and a mechanical shell anchor. When the smooth bar is torqued, the conical wedge pushes the shell anchor against the borehole wall. Coal mines use mechanical bolts in addition to other types of bolts to control the deformation and stabilize the yielded coal ribs. Limited research has been conducted to understand how a mechanical anchor performs in a coal rib. Researchers from the National Institute for Occupational Safety and Health (NIOSH) conducted the study described in this paper to define the loading characteristics of mechanical bolts (stiffness and capacity) installed in coal ribs at five underground coal mines. Standard pull-out tests were performed in this study to define the loading characteristics of a mechanical rib bolt. Based on the strength of the coal seam and the conditions of the coal mines, the bolts were installed at different amounts of torque. A typical tri-linear load-deformation response was obtained from these tests. It was found that the anchorage capacity depends on the coal strength, and the anchorage stiffness depends on the installation torque. The outcome of this research provides essential data for rib support design. INTRODUCTION Rib falls are a serious hazard in underground coal mines. In the last 10 years, rib failures have resulted in 17 fatalities, representing 52% of the ground-fall fatalities in underground coal mines in the United States (MSHA, 2018). Although resin bolts has been used increasingly in the last few years to control coal ribs, mechanical bolting (mainly expansion-shell bolts) is still used in many underground coal mines. Recently, NIOSH researchers surveyed 90 sites in 14 underground coal mines in the Eastern United States and found that 79% of the mines determine their rib support requirement based on the depth, mining height, and the loading conditions, of which 35% use the conventional mechanical bolts. Conventional mechanical bolts are preferable for rib support because they do not require the miners to be too close to the rib during rib bolting. Hence, using the conventional mechanical rib bolts can reduce the risk of injuries and fatalities during the installation process. The mechanical bolt or the point-anchored bolt is the oldest type of rock bolt that is still in use today. The point-anchored bolt is a tensioned bolt anchored down the hole with a mechanical expansion shell or a grouted medium (Peng and Tang, 1984). Figure 1 shows the components of the mechanical anchor bolt. The mechanical anchor bolt consists of a plug, a shell anchor, a headed smooth bar with the top end threaded, a bearing plate, a hardened washer, and sometimes a friction-reducing washer. The shell anchor can be either standard or bail type. The shell of the standard type is held in place by a nut, while the bail anchor uses a strap to hold the shell in place (Peng, 2008). The diameter of the smooth bar is generally 5/8 in for the #5 bolt or 6/8 in for the #6 bolt. The diameter of the hole that the bolt is inserted into must be carefully controlled since an oversized hole can result in poor anchorage (Moss, 1971). The anchorage is obtained by applying torque to the bolt head, which in turn pulls the wedge down in the shell and expands the serrated leaves against the sides of the hole-wall. In the resin-grouted anchor, the resin replaces the mechanical expansion shell at the end of the hole. The anchorage is achieved by bonding between the resin, bolt, and the hole-wall.

Jan 1, 2019

By A. J. S. Spearing, B. Forbes, T. Kostecki, A. Hyett

Improving upon the past understanding of the interaction between installed rock bolts, the immediate roof and sidewalls is vital for the implementation of sound support system design, as this has a direct impact on rock-related safety. This is the primary goal in rock-bolt-related research. The earliest research in this field concentrated on limited laboratory and in situ measurements accompanied by theoretical analyses, based on the Kirsch equations. This represented the initial insight into understanding relative ground movements and their impact on primary support. However, these studies were far from complete. More recently, major technological advances in computing power within the mining industry has changed the scope from theoretical analysis to computer simulation. Even with these advancements our understanding of rock bolts in situ and in the laboratory has not progressed, particularly concerning bending and shear. To measure the behavior of rock bolts, the widely accepted practice is to populate the bolts with an array of strain gauges. Historically, resistive foil strain gauges or long displacement sensors have been used. Additionally, all instrumented rock bolts have used only two diametrically opposed slots. Rock bolts instrumented with these methods have significant shortcomings, one of which is the inability to capture shear and bending. The shearing and bending of rock bolts are particularly common in tabular soft rock mining, such as coal mining. This paper discusses the use of three slotted rock bolts, cut diametrically 120º apart, and two new optical fiber technologies populated along the entire rock-bolt length.

Jan 1, 2015

By S. C. Suboleski

Underground long-range planning and mine design is an iterative process beginning with a specified production level, quality criteria, and geology of the deposit. Given these factors, face equipment is selected, the number of units needed and production per unit are calculated, and the mine infrastructure needs are developed. The scheduling of units then follows, with the design of the various support systems coming next. The support systems needed to maintain production can be grouped as follows: (1) outby haulage of mined material, (2) supply and manpower haulage, (3) ventilation and associated environmental considerations, (4) drainage, fresh water, and related considerations, (5) rock mechanics, and (6) power, supply. Thus, long-range planning may be viewed as a three-tiered structure, with the data on required production, product quality, and geology at the upper level; the development of face production capacity and the scheduling of units sufficient to meet the needs of the first two at the second level; and the development of support operations for the production units at the third level. Changes at any level may affect not only the items on that tier but may also cause a change to the items on the tier above and below. For example, if the rock mechanics data indicate that desired opening sizes will not be stable, then this situation will affect not only the ventilation design but also the production rate and possibly the selection of equipment itself. These, in turn, may affect the scheduling of units and the number of units, ultimately influencing the entire third tier of systems.

Jan 1, 1979

By W. C. Lacy

It is the responsibility of educators to look ahead and prepare young engineers and scientists to cope with industrial and social problems of the future. We are faced with a review of history as well as prophesy of the future. The mining industry exists in a "bubble" with little interaction or communication with the outside. This isolation must be broken down if the industry is to survive in the U.S. and Canada. The ability to communicate with the general public and public officials is essential. Many changes are occurring that will require readjustments in technology and staffing. Aging population will result in raising retirement and increasing available workforce. This may force shorter working weeks to supply additional jobs. Environmental concerns will likely direct more attention not only to these concerns during mining, but to planning for post-mining land usage. Retraining and up-dating educational programs are required to cope with these changes.

Jan 1, 1994

By Joseph C. Rota, Charles E. Ekburg

Introduction The Gold Quarry gold deposit is the largest bulk tonnage epithermal gold deposit in northeastern Nevada to be developed by Newmont Gold Co., formerly known as Carlin Gold Mining Co. Exploration and development of the deposit extended over a period of nearly 50 years before bulk tonnage mining became economically feasible. Proven reserves at Gold Quarry are currently estimated at more than 255 t (8.2 million oz.) of gold, accounting for more than 40% of the total Carlin Trend mineable reserves for 1986. Milling began in late 1985; dump leaching of lower grade ores began in May of 1986. The mill has exceeded the initial design throughput rate of 6.3 kt/d (7000 stpd) and is now processing more than 8 kt/d (9000 stpd). The dump leach facility will process more than 7.3 Mt (8.1 million st) of lower grade ores in 1986. The Gold Quarry ore body is to be developed by an open pit that will eventually be 1830 m (6000 ft) long, 1220 m (4000 ft) wide and 300 m (1000 ft) deep. The mine currently produces 77 kt/d (85,000 stpd) on a 24-hour-a-day, seven-day workweek. Planned pit production will increase to nearly 168 kt/d (185,000 stpd) in 1988. Production equipment currently includes one Demag H-/285, three Komatsu PC-1500 hydraulic shovels, two Cat 992C loaders and 21 90 to 135 t (100 to 150 st) haul trucks. Mining is conducted on 8 m (20 ft) benches within the Paleozoic

Jan 4, 1988

By Y. Topkaya, R. E. Johnson, B. R. Palmer, Jia-Jun Ke, Da-Ping Kang

The kinetics of the leaching of antimony oxide ore (Sb2O4) in aqueous hydrochloric acid solutions has been investigated. This dissolution reaction is a heterogeneous solid-liquid reaction. It has been found that the leaching temperature and the concentration of hydrochloric acid turn out to be the significant influencing factors on the leaching rate. The apparent activation energy for the leaching reaction was determined to be 63.5 W/mol within the experimental temperature region of 50O to 90O C. The experimental results indicate that the leaching process is controlled by the rate of the chemical reaction.

Jan 1, 1993

By H. Huang, J. C. Wu, C. H. Xie, Y. Q. Xue, Z. H. Zhang

Two- and three-dimensional groundwater flow models for dewatering in an opencast mine are presented. The models focus on solving special problems using numerical simulations of the opencast mine. These special problems include the drying up of the aquifer, the movement of the model boundary and the prediction of the residual head. These models are used to describe the decline of groumdwater levels in the Yuanbaoshan Opencast Coal Mine and its neighboring area during the drainage period. The simulated values agree very well with the field data. There have been several successful examples of numerical simulation for predicting the mine dewatering rate in an opencast mine. However, The hydrogeological conditions for the Yuanbaoshan Opencast Coal Mine are rather complex, and the total average flow rate is very high at 4.676 x 105 m3/d (1.65 x 107 cu ft/day). In this paper, a two-dimensional groundwater flow model in a large area is developed to solve the problems mentioned above by simulating regional drawdowns of the groundwater level during the drainage period, and a three-dimensional flow model is developed to simulate the residual head near the open-pit bench.

Jan 1, 1998

By Y. Topkaya, R. E. Johnson, B. R. Palmer, R. B. Bhappu, Ronald J. Roman

The hydrodynamics of the leaching solution in leach heaps is known to be one of the important variables in the performance of the heap. The solution hydrodynamics are also important in the decommissioning of a heap where the aim is to flush out the residual dissolved metals and the remaining reagents. Chemical engineers have studied the hydrodynamics of "trickle bed" reactors for 40 years in an attempt to relate the performance of trickle bed reactors to flow conditions. Their work is reviewed with emphases on areas of similarity to heap leaching.

Jan 1, 1993

By J. H. Rowland, R. A. Thomas, III, C. D. Litton

Atmospheric monitoring systems (AMS) are required when using air from conveyor belt entries to ventilate working sections in U.S. underground coal mines. AMS technology has the potential to increase fire safety mine-wide, but research is needed to determine the detection and response times for fires of a variety of combustible materials. To evaluate the potential of an AMS for fire detection in other areas of a coal mine, a series of full-scale fire experiments were conducted to determine detection and response times from fires of different combustible materials that are found in U.S. underground coal mines, including high- and low-volatility coals, conveyor belts, brattice materials, different types of wood, diesel fuel, and a foam sealant. These experiments were conducted in the Safety Research Coal Mine (SRCM) of the U.S. National Institute for Occupational Safety and Health (NIOSH) located in Pittsburgh, PA, using a commercially available AMS that is typical of current technology. The results showed that through proper selection of sensors and their locations, a mine-wide AMS can provide sufficient early fire warning times and improve the health and safety of miners.

Jan 1, 2016

By R. J. Pruett

Selective flocculation enables the production of high-brightness kaolin products from kaolin ore once considered too poor in quality for beneficiation into paper-coating pigments. Anatase, Ti(1-X)FeXO2, with X = 0 to 0.05, is a common iron-bearing impurity in sedimentary kaolin that can be unresponsive to kaolin beneficiation processes, such as magnetic separation, due to its extremely fine particle size (<0.3 µm), or chemical bleaching, because of its chemical stability. Described here are selective flocculation technologies that separate anatase by flocculating anatase or flocculating kaolinite from dispersed slurries. Applying the advances in the chemical and mechanical dispersion of ultrafine particles and the selective aggregation of kaolinite or anatase particles have resulted in the selective flocculation processes practiced today that have increased process recoveries from those technologies practiced beginning in the 1960s.

Feb 1, 2012

By J. Weyer

"A lot of incorrect, dangerous and misleading statements about the effect of CO2 on the human body can still be found in the internet, the media and in books. It is a fact that already low concentrations can lead to critical reactions, higher concentrations cause a narcosis. The real effect is not a lack of oxygen but an inner suffocation. The breathing reflex is decreased and the transport of oxygen in the blood is reduced due to a low pH value of the blood. Furthermore a reduced oxygen content in the air can also lead to the failure of diesel engines. MOTIVE Different gases can appear in active mines as well in abandoned mines, adits and caves. The most dangerous gases are CO, NO/NO2, H2S, SO2, CH4 and CO2. Although the general danger arising from these gases is mostly known some aspects are underestimated. Furthermore misleading or wrong statements exist about the detection and the effect of gases on the human body. This is especially true for CO2. In the last years a couple of accidents happened with a great number of injured persons and unfortunately also some fatalities. As a result wrong information and comments about the effect of CO2 have been published in the media. A huge unexpected CO2 outburst in a potash mine showed again some additional problems and limits for rescue troops. ORIGIN OF CO2 AND MISLEADING STATEMENTS ABOUT THE EFFECT ON THE HUMAN BODYCarbon dioxide can appear as free gas in the earth crust. It is especially known in significant concentrations in some potash deposits, in hard coal mines and some caves. Furthermore it can be formed due to complete oxidation of carbon. It can appear in technical processes. It is also used for or in technical processes, as fire extinguishing agent, as cooling agent, it is contained (added) in sparkling water or other soft drinks and it is formed by fermentation processes. Up to today a lot of wrong information about the effect of CO2 on the human body is published or is still in the mind of many people and unfortunately even in the mind of members or leaders of rescue troops. On August 16th 2008 a faulty CO2 extinguishing installation in the city of Mönchengladbach/Germany caused the injury of 107 people and the evacuation of further 150 people /1/. People on the streets became unconsciousness and felt down. Fortunately all could be rescued due to the immediate rescue operation of local fire fighters. Furthermore the CO2 concentration on the ground was diminished by help of a helicopter. What could have happen with the engine will be discussed later. After 6 days a second similar accident took place /2/. In the news members of the rescue teams explained that CO2 leads to suffocation due to a lack of oxygen. This is wrong! Also cave explorers often say that a burning candle can detect a low oxygen and/or high Carbon dioxide content in the air. This is also wrong and deadly dangerous! Similar statements we find nowadays in the internet /3, 4 and many other/. In a forum “science and mathematics > chemistry” several people say that winegrowers go with a candle into the vine-cellar to detect CO2 /5/. Again: this can be deadly! Another dangerous statement is that CO2 in higher concentrations leads to headaches so people should leave such areas. A last example found in the literature is that at 3 % the breathing volume is doubled and at a concentration of 20 % one can felt some warmth on the skin. Both is not wrong but can lead to false conclusions. /6/"

Jan 1, 2015

By C. Heckman, M. S. Moats, A. Luyima, W. Cui

"Chloride ions and their interactions with two organic smoothing additives – Cyquest® N-900 and HydroStar® 4208 – during copper electrodeposition were explored using cyclic voltammetry and electrochemical impedance spectroscopy. The results revealed that chloride ions, up to a concentration of 40 mg/L, depolarized the copper deposition reaction. A combination of chloride ions and Cyquest N-900 inhibited the depolarization reaction during copper electrodeposition. It is proposed that the chloride ions acted as bridging ligands between copper and Cyquest N-900. Addition of HydroStar at a concentration of 2.5 mg/L depolarized the copper deposition reaction when no chloride ions were present. This behavior did not change with the addition of chloride ions at the concentrations tested, indicating that chloride ions and the polysaccharide do not interact.IntroductionElectrowinning is a major production method used to obtain high-purity copper. In modern tankhouses, copper is electrodeposited onto stainless steel blanks and then stripped, washed and bundled for delivery. Significant improvements in the quality of electrowon copper have been made over the last few decades. Additives, temperature, current density, electrolyte concentrations and agitation are known to influence the quality of copper electrodeposits (Jenkins and Eamon, 1990).The influence of chloride and organic additives on copper electrodeposition has been the subject of considerable research. The addition of small quantities of chloride and organic additives has been recognized to significantly improve the properties of copper electrodeposits. These additives are critical in the prevention of dendrite growth and the production of smooth, dense cathode deposits.Chloride ions have been reported to catalyze the copper reduction reaction and assist in the production of uniform deposits (Lakshmanan et al., 1977; Sun and O’Keefe, 1992). Moreover, it is generally agreed that chloride ions depolarize the copper deposition process at low (several millimolar) chloride concentrations. This is because chloride ions catalyze the reduction of copper (II) ions to copper (I) ions (Cu2+ ? Cu+ + e-) in the rate-limiting step of this process (O’Keefe and Hurst, 1978; Ilgar and O’Keefe, 1997; Hebert, 2005; Shao, Pattanaik and Zangari, 2007)."

Jan 1, 2016