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By Scott Lewis, Andrew Kositsky

"INTRODUCTIONThe South Napa Earthquake of 2014 caused ground motion at numerous reinforced concrete-lined (shotcrete-lined) winery tunnels in Napa County and Sonoma County, California. The occurrence of seismic ground motion at these tunnel complexes, known as wine caves, presented an opportunity to reevaluate seismic performance of reinforced concrete and reinforced shotcrete lined tunnels. The authors of this paper updated the most recent comprehensive compilation and evaluation of case studies by Power and others (1998), which correlates peak ground acceleration (PGA) at tunnel sites to damage. For this update, the authors evaluated the seismic performance of 31 wine caves near the South Napa Earthquake epicenter; including some of the 90 wine caves they designed since 1991, some caves designed by others, and additional caves constructed by contractors that they frequently work with. Tunnel designers can use the new data presented in this paper to help evaluate the usefulness of detailed seismic design analyses. THE SOUTH NAPA EARTHQUAKE The South Napa Earthquake occurred at 3:20 AM Pacific Daylight Time on August 24, 2014. Figure 1 shows the approximate location of the epicenter, the measured/estimated PGA contours, and the location of wineries with wine caves added to the database where the PGA was at least 0.2 g. The epicenter was along the West Napa fault, about 5 miles south-southwest of downtown Napa, California. The earthquake moment magnitude was 6.0, and measured/estimated PGAs were up to about 0.7 g. The duration of strong shaking was about 10 seconds. This earthquake was characterized by right lateral strike-slip fault movement, ground surface rupture, and after slip at the ruptures. Increased surface water flows were observed at seven creeks after the earthquake. Groundwater level rises of up to 5 feet were observed in Sonoma County wells after the earthquake. The earthquake was the largest seismic event in the San Francisco Bay Area, which includes Napa and Sonoma Counties, since the 1989 Loma Prieta Earthquake. The Napa event caused an estimated $400 million in damage. This damage included moderate to extensive structural damage to older commercial buildings and to some newer buildings in downtown Napa. This damage resulted from ground motions, subsequent fires, and failed underground utility systems."

Jan 1, 2016

By Thomas N. Walthier

This paper will review world trends that are increasingly restrictive of mineral exploration and mining throughout the Free World This is occurring in the face of projected huge increases in demand for mineral products Some of the impediments are direct and absolute; others are indirect, but nevertheless effective; still others represent merely hostile attitudes Many of the world governments have a reputation for lack of integrity in dealing with existing foreign investments within their borders, and consequently are quite uninviting places for new investments, especially in the capital intensive natural resources industry. Compared with even 35 odd years ago (and pre-World War II is not that long ago) there are few places left where private mining investments are both wanted and where investors are willing, to go. We shall begin with an analysis of conditions in the U. S., shift to neighboring Canada and Flexico, and then have a look around the world. As the world grows smaller for the private mining sector, the function of exploration, development, and operation is passing over to government. We'll conclude with a view of what this holds for the future

Jan 1, 1976

By J. D. Patsey, G. T. Lineberry

Introduction A computer program was developed for analyzing drum-type hoists before modifying an existing system or designing a new one. Its use permits the preliminary evaluation of a system before seeking technical assistance from mine hoist designers and manufacturers. The user-friendly program accepts a variety of data and analyzes hoisting systems for any balance state. The program can be used to calculate skip capacity to yield a desired production rate, solve for drum face width, select a permissible wire rope, estimate total horsepower of the hoist plant, and estimate annual power cost. Whether required for a large mining complex or for a relatively small operation, a hoisting system must be carefully designed to ensure the efficient, reliable, and safe flow of material. Because shaft sinking and hoist installation can total between 2.5% and 3% of the cost of opening a deep mine, proper hoist selection is critical. Today's mining engineer has at his disposal the most powerful design and analytical aid ever, the microcomputer. There is, unfortunately, limited software for the study of hoisting systems, unlike that for other materials handling equipment (Manula and Albert, 1980; Prelaz et al., 1964; Bucklen, 1969; Thompson, 1985). HOIST reduces a time-consuming set of calculations to a concise package of interrelated subprograms. A literature review revealed no common-user programs to analyze hoisting systems, although at least four major hoist designers/manufacturers/installers have their own in-house programs. To provide a tool with which the mining engineer could preliminarily analyze a materials hoisting system or could check the calculations of a hoist contractor, a computer program was developed. HOIST was written in BASIC for the IBM-PC for ease of program adaptation and to encourage field use on compatible systems. Details of program development are omitted, since the basic principles of hoisting analyses are relatively straightforward, simple, and readily accepted (Harmon, 1973; Nordberg, n.d.; Adler, 1957). Program features, intended usage, and benefits of the computerized solution are emphasized over theory development and mathematical rigor. Background The mine hoist system that is selected and installed at a mine is the "lifeline" of that mine, with installations lasting 20 years or more. Thorough study is warranted to ensure that productivity demands are met at a minimum cost per ton. The increased cost of a large, powerful, high-speed hoist must be offset by increased production to justify its selection. To optimize this tradeoff, an extensive hoisting analysis should be performed. The analyses to properly size the skip (or cage), the drum, and the hoist drive are conducive to computerization, permitting rapid evaluation of changeable operating and design parameters, such as velocity, acceleration, state of balance, and productivity demand. The program is particularly useful in conducting sensitivity trials, such as investigation into the effect of change of productivity on skip capacity and on horsepower of the hoist drive. HOIST is currently limited to the study of drum-type hoists with cylindrical drum(s). However, only minor changes to the program would permit analysis of friction hoists and conical drum configurations. Model development and testing The program is based on accepted equations and physical relationships. Examples of manual calculations formed the basis for decision points and program branching. Data is input in the order that it would be needed if the problems were solved manually. The choices are arranged likewise. HOIST was developed in sections, with manual solutions performed to check program logic. The testing became more rigorous as sections were completed. Output from one section becomes input for following sections, as appropriate. The simplified flow diagram of HOIST is given in Fig. 1.

Jan 2, 1987

By S. A. Shoop, J. J. K. Daemen

Site-specific blast vibration prediction can be more accurate than using a universal prediction equation. Vibrations from 37 blasts were monitored using three seismographs. Data analysis showed that square root, cube root, and site-specific scaling predicted ground motion with equal reliability. Imprecise prediction is caused by geologic and blast variability, particularly, inaccurate delay times. Vibrations at some mines were consistently lower or higher than vibrations predicted from US Bureau of Mines (USBM) equations. Vibration restrictions based on USBM studies could then be too conservative or too lenient. Predominant vibration frequencies were generally less than 50 Hz, but several blasts had significant energy up to 125 Hz. In some cases, energy was concentrated at frequencies corresponding to delay intervals.

Jan 3, 1985

By Todd Minoski, Matthew McElhinney, Morgan Sears, Craig Compton

In an effort to advance the science underlying ground control engineering, researchers with the National Institute for Occupational Safety and Health (NIOSH) are frequently involved in field studies at collaborating mines. Often, these field studies involve visiting the mine site, instrumentation installation, and data acquisition. Each of these aspects involve potential risks to NIOSH employees. As an organization whose mission it is to promote the health and safety of mine workers, the health and safety of our workforce is paramount. This paper provides documentation of the best practices followed by NIOSH employees who are tasked with visiting and conducting work at underground and surface mines. This includes Mine Safety and Health Administration (MSHA) approved training, mine site specific training, and hazards associated with all aspects of mining that could be encountered by the employee. Additionally, this paper details best practices associated specifically with instrumentation installation including the mitigation of hazards associated with the proper equipment handling, drilling, and the mine environment. The information showcased in this paper can be used as considerations for industry practitioners such as mine operators, consultants, and academic researchers engaged in the installation of instrumentation in the field. Furthermore, the best practices detailed in this paper can be used as a foundation for agreements made between mine operators and researchers to ensure safety procedures will be followed while on mine property. This will result in enhanced safety of both researchers involved in field studies as well as mine employees tasked with assisting and accompanying those researchers.

Feb 1, 2024

By O&apos

Southern Ohio Coal Company (SOCCO) and the U.S. Bureau of Mines have identified techniques to optimize the use of scrubbers on continuous miners. The techniques provide maximum respirable dust control while maintaining a high output. The use of radio remote control and scrubber help to achieve greater advance between lifts by locating the operator in fresh air during the mining cycle. He is also kept away from newly exposed roof, which is not supported. An alternative to fan-powered scrubber was also evaluated at SOCCO. A high-pressure water-powered scrubber system eliminated the noise associated with fans, and achieved an intrinsically safe system. Experience in the use of these scrubber systems and remote control at SOCCO are discussed.

Jan 1, 1990

By Todd Clarke, Ralf Winterberg

For more than a decade the tunneling industry has explored the potential and benefits of macro synthetic fiber (MSF) reinforced concrete solutions for precast tunnel segments. Parallel to industry investigations, academic research is being undertaken to better understand this material when subjected to the typical loads expected during mechanized tunneling. This paper investigates the performance of MSF reinforced precast concrete tunnel segments by means of an experimental program comprising testing of full-scale tunnel segments. The presentation of the satisfactory results of the experimental testing regime will be complemented by a brief case history from a successfully executed project—an America’s First.

Jun 13, 2021

By TUIJA MONONEN, LUDGER BENIGHAUS, CHRISTINA BENIGHAUS, Virginia del Rio, SARI KAUPPI, JUHA M. KOTILAINEN, JAVIER GÓMEZ, JARI LYYTIMÄKI

The understanding of public debates over mineral exploration and mining largely originates from exceptional situations such as mining accidents of conflicts. Less is known about how mining is portrayed and understood under more conventional settings. What storylines dominate the local day-to-day public debate? This article presents results from a comparative case study focusing on newspaper coverage of mineral exploration and mining in three European countries representing different geological and socio-economic contexts. Newspaper articles from the Geyer-Erzgebirge region in Germany, the Andalusia region in Spain, and Northern Finland are studied. The sample looks into the period between September 2018 and February 2020 and shows that regional newspapers report about mining issues relatively intensively even in the absence of major accidents or other media events causing peaks of attention. The tone of the articles is generally neutral to positive towards mining activities, reflecting the specific local settings, historical experiences, and future expectations. Despite the different contexts of the three countries, there were considerable similarities to the topics highlighted, including common themes of mining revival, mining events and social interaction, history of mining, and damages related to mining. Past, present, and future employment opportunities related directly or indirectly to the mining sector are key storylines. Another recurrent underlying theme is the need to balance environment and safety risks and socio-economic prosperity, typically covered through ordinary disputes among the mining sector, public authorities, regional non-governmental organizations, and local initiatives.

Jul 6, 2021

By O. M. Arafat, J. A. Finch

Since its development, the functional performance equation for ball milling (McIvor, 1988) has facilitated a new understanding of industrial circuit cause and effect relationships, leading to significant strides in operational performance. Success stories of this approach to plant circuit performance improvement are now too numerous to list. Finch and McIvor (circa 1986) also discovered that the functional performance mill grinding rate at the size of interest was the same cumulative grinding rate that is calculated from mill feed and discharge size distributions using a first-order rate equation. By calculating these cumulative grinding rates for all screen sizes, a complete ball mill model is generated (as used by Finch and Ramirez, 1981). Others in industry, Hinde and Kalala (2009), for example, have noted the same. Lacking the complexity needed to maintain their interest, most researchers have ignored this model, broadly opting instead for Epstein’s (1948) characterization of grinding as a chemical reaction, combining selection rate and breakage size distribution functions. The much simpler ball mill model has previously been incorporated into a proprietary circuit modeling program (McIvor, 2005) and used for plant improvement work (for example, see McIvor and Finch, 2007, and McIvor, 2014). Now, by combining this business-friendly ball mill model with optimization criteria from functional performance analysis, a circuit modeling system (including the needed supplementary steps to assure successful plant implementation of circuit design changes) is at the disposal of every plant metallurgist, grinding equipment/ material provider and circuit designer.

Jan 11, 2017

By Robert D. Hansen, Basil S. Fee, Richard R. Klimpel

Despite the importance of froth flotation to the mineral industries as a means of separating various minerals, the commercial flotation reagents used have varied little in the last twenty years. Numerous articles and books are available describing existing flotation chemistry and its application, e.g., Fuerstenau (1962), Fuerstenau (1976), Aplan (1980), Somasundaran (1980), King (1982), Leja (1982), Ackerman, et. al. (1984), Crozier (1984), Hansen and Klimpel (1985). There are many reasons for this lack of significant new reagent development including the general utility and relative cheapness of collectors, such as xanthates, and frothers, such as methyl isobutyl carbinol and the glycol ethers. Another important reason is the inherent complexity of the flotation process itself coupled with highly variable and difficult to standardize feed materials which make reliable reagent comparisons difficult and seriously limit the use of theoretically based studies to "predict" new or optimal reagents. In addition, the higher cost of "specialty flotation reagents demands that their performance attributes be significantly greater than existing general all- purpose commercial reagents – something often difficult to prove in practice. Faced with this situation, a detailed applications research pro- gram [Klimpel (1980 ab, 1982, 1984 ab), Klimpel, et. al. (1982)] was organized from 1979-1985 on mineral flotation with the following goals: 1) the development of appropriate batch laboratory flotation testing techniques sensitive enough and statistically reliable enough to identify small differences in performance between different flotation tests (i.e., between various reagents, even those with relatively minor chemical structural changes); 2) the identification of mathematical models with appropriate numbers and types of parameters that have maximum statistical power to statistically distinguish between various time-recovery profiles; 3) the generation of laboratory and corresponding plant scale data in sufficient quantity and consistency so that the highly interactive nature of the "flotation system9' of chemistry/ equipment/operating conditions could be quantified; and 4) the invention and development of really new and unique reagents for giving improved flotation performance. The goal #1 was achieved [Klimpel (1980b. 1984b), Meyer and Klimpel (1984)l by basically using a simple automated paddle device for consistent

Jan 1, 1986

By F. Maciosek, D. Denton, J. Johnson

Researchers from the Spokane Research Laboratory of the National Institute for Occupational Safety and Health and personnel from Coeur Silver Valley, Wallace, ID, conducted tests using rock strain strips and Split-Set rock bolts instrumented with strain gauges to monitor wall rock strain at the Galena Mine, Osburn, ID. The objective of the test was to identify whether strain on the rock bolts increased prior to a rock burst. Although results were inconclusive, researchers learned that the Split-Set rock bolts yielded in stick-slip fashion in the highly jointed walls of the stope. The bolts were also bent as stress was redistributed following blasting and subsequent movement along joints in the wall rocks.

Jan 1, 2004

By Steve Kral

The dramatic rescue of nine Pennsylvania coal miners trapped nearly 90 m (300 ft) underground for77 hours probably would not have happened without the high technology equipment and improved mine rescue training techniques available today. By now, most everyone has heard the story of the accident that occurred at the Quecreek Mine near Somerset, PA. At about 9 pm on Wednesday, July 24, the miners were drilling coal in the room-and-pillar mine. Their drilling accidentally punched through to the adjacent, abandoned Saxman Mine. Old mine maps of the Saxman Mine led Black Wolf Coal, Quecreek’s owners, to believe they were between 60 to 90 m (200 to 300 m) away from the abandoned mine. Those maps proved to be inaccurate.

Jan 1, 2002

By William Gleason

"Government support for Canada’s mineral industry was on full display during the Prospectors & Developers Association of Canada (PDAC) conference in Toronto, ON, Canada on March 3-6. First, there was the announcement of the five-year extension of Canada’s Mineral Exploration Tax Credit (METC), the first multi-year extension of the METC since its inception in 2000. Canada’s Minister of Natural Resources, Amarjeet Sohi, added to that support when he spoke at the opening keynote session and announced the Canadian Minerals and Metals Plan (CMMP), a plan that aims to map out the future of the industry in Canada. Finally, the support for the mining industry was buttoned up with a visit to the conference by Canadian Prime Minister Justin Trudeau.More than 25,000 people from 135 countries attended the annual conference that features a robust trade floor, technical sessions and an investors’ exchange that aims to put mining companies in touch with potential investors. Mining companies and ambassadors from nations around the world are given the opportunity to present to small audiences throughout the conference and this year PDAC was able to sway the Prime Minister to speak on its behalf.Trudeau sat down with PDAC President Glenn Mullan on March 5 to talk about the METC extension and a host of other issues important to the Canadian and global mining industry, giving the home country a bit of a profile advantage when it came to making a pitch to investors.Trudeau entered the week of the conference in the midst of the most serious political scandal of his career and was defending himself against accusations of political interference with the top prosecutor in the land over a criminal case involving one of Canada’s largest companies, SNC-Lavalin. During the question-and-answer session at the Metro Toronto Convention Center, Trudeau seemed more than happy to keep to the discussion about mining. He spoke favorably about the industry during the half hour conversation and praised the industry for its work with Indigenous people as well as its efforts to advance technology and innovation. He made a case that Canada is a safe and reliable place for investment in the minerals sector.“We are at a time of change right now, of transformation with new technologies and global supply chains, and everyone is trying to adjust to the new realities that have accelerated so much these past years,” Trudeau said. “What we are trying to do as a country and what you have done as an industry is to try to look at where things are going – go to where the puck is going to be, not where it is. You, as an industry, know that investments in innovation, research, science — investment in technology and partnerships with Indigenous communities are all things that are going to give you opportunities to be competitive in the coming years.”"

Apr 1, 2019

By C. V. Deutsch, D. A. Silva

The geologic modeling of multiple domains is required for the prediction of mineral resources and reserves. In general, explicit methods have wide acceptance among modelers due to the ability to manually add deemed important trends and geological features into the models. As an alternative, implicit geologic modeling techniques are increasingly adopted to reduce professional time requirements. These methods aim for objective, repeatable and flexible models by replacing the manual time-consuming interpretation of sections with the interpolation of signed distance values. These techniques, however, have been developed for the binary case of two domains at a time. The current paper presents an algorithm that extends the binary case to multiple domains. The method is able to transfer large-scale geological features from data to geologic models. A case study illustrates the benefits of the algorithm and practical implementation considerations.

Jan 1, 2016

By R. T. Richins

Coeur d'Alene Mines Corporation (CDE) is a precious metals mining company. The company's three mining operations are located In Nevada and Idaho. Collectively, these mines (Rochester in Nevada, and the Galena and Coeur In Idaho) produced about 61,000 ounces of gold and more than 7.5 million ounces of silver in 1991. The company is currently planning the development of two major properties; the Fachinal gold-silver project in Chile and the Kensington gold project near Juneau, Alaska. Fachinal and Kensington hold encouraging potential to significantly expand CDE's gold production during this decade. The permitting process for these two distinctly contrasting environmental settings, project design requirements and regulatory/political circumstances provide the basis for a comparative analysis of licensing and permitting requirements, timeliness of the permitting process and costs in the U.S. and Chile.

Jan 1, 1993

By James A. Madonna

Several universities and colleges in Australia, Canada and the United States, recognized the need to establish or reorganize geoscience programs at the vocational and two-year technical levels. To accomplish this, a cooperative study with industry in one state or province from each country was initiated. These include Tasmania in Australia, British Columbia in Canada and Alaska in the United States. The objective of this work was to develop a diversified geoscience educational model at the two-year technical, vocational and continuing education level that provides the source from which any nation can draw the proper educational tools to create a new geoscience program, modernize an existing program or strengthen a weak program. More than 100 mineral industry organizations provided information regarding their specific training needs for support personnel. The data gathered have been used to identify training areas for semi-skilled, skilled and technical personnel in geochemical mineral exploration. These included geological, geochemical, environmental and computer skills. With the areas of major educational need defined for geochemical exploration, an educational field skills model was developed for the three levels of training. The international need for a study of this type was recognized as early as 1980, following numerous contacts from domestic and foreign geoscience educators regarding the structure and success of training within the University of Alaska Fairbanks Mining Extension program, located in Fairbanks. Contacts, correspondence and visits included educators from Australia, Brazil, Canada, Mozambique and the conterminous United States. The need was magnified between 1985 and 1989 at the University of Alaska Fairbanks, when an attempt failed at initiating and developing a two-year geoscience vocational-technology program leading to an Associate of Science degree.

Jan 1, 1994

By M. A. Trevits

Mine seals are used in underground coal mines throughout the United States to isolate abandoned mining areas from the active mine workings. The objective of adding inert gas to a sealed mine area is to quickly reduce the oxygen concentration in the sealed area to a level that will not support combustion. In the US, this process is typically conducted from the ground surface and because surface-to-mine access is constrained by so many variables, it is very difficult to provide a source of inert gas to the place where it is needed underground. To alleviate this problem On Site Gas Systems, under a NIOSH contract, built a nitrogen (N2) generation plant that operates in the underground environment. The purpose of this work was to create a reliable in-mine mobile plant that would extract N2 gas from the mine atmosphere and use the gas to create and maintain a safe sealed mine area. The plant is based on a novel design using pressure swing adsorption technology and is sized to fit on a standard shield car or mine dolly for easy transport in and around an underground coal mine. The plant is capable of producing about 900 scf/min of N2 gas at ambient mine conditions. After an exhaustive series of laboratory tests, the plant was field tested at the NIOSH Safety Research Coal Mine (SRCM) where a portion of the mine was sealed and rendered inert. During the test, the movement of the injected gas was monitored at several underground points to observe the progress and extent of the inerting process. This paper describes the plant design and the results of the field test at the SRCM. Disclaimer: The findings and conclusions in this report are those of the authors and do not necessarily represent the views of NIOSH.

Jan 1, 2009

By C. Pitzer

"Safety performance in many companies and even industries has stalled in the last decade. Accidents rates are at a “plateau” and yet, serious accidents and fatality rates are not. In more dramatic cases, such as in the BP Texas Refinery disaster, organizations that have “exemplary” safety statistics, suddenly have a catastrophic or multi-fatality event occurring. Classic examples are the Piper Alpha disaster and NASA’s Challenger and Columbia disasters, the BP’s Deepwater Horizon Rig disaster in the Gulf of Mexico. Looking into the causes of these accidents provides an insight into the events and deficiencies that led up to the accident, but what are the common features in the organization’s mindset, or its culture? What characterizes these organizations’ decision-making, their approach to safety and to risk and are there features that can be delineated? The research and review presented in this paper covers a period since1995, which started in the Australian resource industry and since then covered international events. The features of these organizations are summarized as the seven deadly delusions of near zero organizations (NZO) that suffered unexpected disasters, based on extensive research by the author. More recently, the massive West Fertilizer plant explosion in Texas, and the Train Disaster in Lac-Mégantic, Quebec, Canada underlined the same trends. Organizations may experience calamities not because they are bad, or unsafe, but because they have become “cult-like”. INTRODUCTION The train disaster of 6 July 2013, in the small town of Lac-Mégantic in Quebec, Canada, in which 47 people were killed, had many strange pre-cursorsso-called “black swan” events that have occurred in many different industries. Black swan events are so rare, that there is almost zero chance that they will ever occur again, but they are so calamitous that the responses to these are emotional and irrational, (but necessary) and in those responses, the seeds for other, different black swan events are put into place. It is not what we don’t do, or do wrong, that causes modern disasters, it is what we do. The same things in the culture that make us successful, may also cause the disasters. We slowly, incrementally and insidiously ‘float’ into disaster. One such Black Swan event: The Piper Alpha Oil Rig disaster, killing 167 men in the North Sea on the 6 September 1988, was one of the most pivotal events in safety around the world. It changed the thinking and focus of governments, whole industries and led to numerous books and papers. It resulted in new legislation, textbooks and a critical self-examination by the oil and gas industry."

Jan 1, 2016

By Paul D. Tomlingson

The difficult and often harsh working environment of the mining industry can stress both personnel and equipment to the extreme. Often, the unintended consequences of this environment lead to confrontations between departments, as each goes about its tasks of mining, maintaining or supporting these activities. On occasion, the confrontations may result in criticism of other departments for perceived or real sins or omissions. The offended department may not be able to change the circumstances, but can only complain while frustration persists. The most effective solutions are the actions of the mine manager. By establishing mutually supporting roles of each department and specifying conditions for the interactive conduct of maintenance, the mine manager can better assure that the inherent problems of the mining environment are neutralized.

Jan 1, 2011

By Vince Saporito

Miners work in dangerous terrain, around the clock, with heavy equipment. Is there room for improvement in safety and standardization in the mining industry? Recent history would suggest there is a need for action. At a 2011 Spring Thaw conference in Denver CO, one speaker commented, ?We are having a number of incidents with workers getting ?pulled? into rollers or ?trapped? at transfer points when trying to manually clean (it) while the conveyor is still in motion.? It?s a troubling thought. These actions are specifically prohibited under U.S. Mine Safety and Health Administration (MSHA) regulation 57.14202. Another official from MSHA earlier this year indicated with today?s technology and policies presently in place, ?we should not be repeating the same incidents and violations year after year as we currently do.? But we are doing exactly that.

Jan 1, 2012