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By Steve Kral

San Francisco, CA will host about 1,500 tunneling and underground construction professionals from around the world during the biannual Rapid Excavation and Tunneling Conference (RETC), June 19-22. These professionals are gathering in a city that has seen much under-ground work throughout its history. And, today, the San Francisco region has more than $4.6-billion in tunneling projects under way. The RETC will include three-and-a-half days of technical programming, complete with proceedings, two short courses, two field trips and a host of social activities. In addition, the accompanying exhibit has attracted 127 exhibitors in 152 booths, an RETC record. The following is a brief list of activities that will take place during the conference. A more complete program is provided in the official showguide that is bound into this issue of Tunneling & Underground Construction.

Jan 1, 2011

By D. J. Carpenter

Safe and successful mine closure represents a fundamental work element that needs to accommodate the geochemical conditions existing at the completion of the mining and ore processing effort. Given the interests in limiting costs and time associated with mine closure efforts enhanced prior understanding of the geochemical conditions likely to exist upon exhaustion of the economic reserves can provide important benefits. The purpose of this paper is to document the benefits associated with geochemical modeling and understanding how the ore formation process may impact mine closure efforts, using one ore deposit type as an example. Specifically, this paper will emphasize the geochemical processes leading to the formation of sandstone-hosted uranium roll-type deposits and how the resultant concentrations and distributions of ore and gangue phases need to be incorporated into understanding the geochemical conditions projected to exist at the end of mineral recovery efforts. The paper will describe the evolution of geochemical conditions leading to ore body formation and the geochemical effects induced by open pit mining and how these may be used to understand both the geochemical controls and constraints on residual mine water. In addition, a discussion will be provided on how these conditions may be simulated by solution equilibria and kinetic modeling to develop optimum approaches to achieve applicable closure standards. This paper will also discuss specific augmentations to existing industry standard solution equilibria and kinetic models and associated thermodynamic databases to maximize the predictive accuracy of the geochemical modeling results. The benefits of understanding the electrochemically reactive behavior of uranium and associated gangue phases and incorporating this behavior into mine closure efforts will be presented. The culmination of the benefits of the geochemical modeling will ultimately be the development of a sustainable approach to uranium mine closure that is based upon an engineered environment designed to return the ore body to stable geochemical conditions.

Feb 27, 2013

By R. W. Chadwick

Coal was discovered in South Africa in the mid 1830's. The earliest exploitation of modern times was probably in Natal where, in a letter dated 20 August 1842, a Captain Smith mentions that a wagonload of coal brought to Pietermaritzburg, was sold. Until the discovery of diamonds in 1867 and the Witwatersrand gold in 1886, coal mining satisfied a very small domestic demand. By 1889, at least four collieries were operating in the Middelburg-Witbank district, some 120 kilometres East of Johannesburg, and mining had star- ted at Vereeniging, about 50 kilometres to the South of Johannesburg. A map of South Africa is shown in Figure 1 and an enlargement of the main coal mining areas in Figure 2.

Jan 1, 1982

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 Barbara B. Newlin, Emily Rosenberg, Marianne Snedeker

Whose longwalls perform best in Eastern underground mines? What is the latest legislation affecting slurry pipelines? What are the trace element constraints on magma genesis? How can process set points be controlled more economically without affecting product quality? Where can I get a paper presented at the Australian Coal Preparation Conference? If answers to questions like these can help with your management decisions, exploration plans, or market positioning, your firm should know about Information on Demand. Information on Demand, Inc. (IOD) is a research service available to SME members to help them get the facts needed to develop business plans. IOD can function as a research staff and data bank specialist for geologists, planning specialists, production managers, and engineers in all levels of the mining industry. Just dial 415-549-3259 and ask IOD for a copy of an obscure article, a comprehensive literature search, or a background report on a company, a process, or a product. Within a short time, IOD will have the information you need delivered to your office or worksite. Information on Demand has a bank of dial-up terminals that provide access to more than 200 business and technical data bases, including Lockheed's Dialog, CompuServe, InfoLine, The New York Times Information Bank, and other systems. These data banks contain more than 95% of the world's technical literature published in the last 10 years. There is no input required from individuals or companies. The data bases are maintained by publishers and are constantly updated with abstracts of articles, reports and reviews, and other text appearing in more than 5,000 engineering publications, as well as thousands of other trade and technical publications. The data bases are organized by subject and offer a speedy comprehensive survey of world literature. One data base, called Compendex, provides worldwide coverage of engineering publications, meetings, and reports. The Metadex data base abstracts literature on the science and practice of metallurgy, and can be accessed by commercial, compositional, and numerical alloy designations. PatSearch and Claims data bases enable IOD to determine what patents have been filed by a given entity, what international patents are equivalent to a US patent, and other vital patent information. In the non-technical arena, the Commerce Business Daily has daily updates of federal procurement information. The Federal Register is abstracted on-line in a data base, and ABI/Inform is a data base full of marketing and management information for all industries. IOD offers a free pamphlet listing these and other data bases. A typical literature search from IOD will produce 60-200 references with abstracts, and can be printed out off-line and mailed or transmitted directly to an electronic mailbox. Abstracts will often give all the information needed by the reader. At times, when the complete article or technical report is needed for further study, IOD will send a photocopy of the full text for a small additional fee. Patents, books, securities exchange filings, standards, and specifications can also be supplied by means of IOD's network in major libraries, such as Harvard, MIT, and The Library of Congress. A technical translation service is available for foreign

Jan 12, 1983

By Richard J. Lundin

Literature research is an inexpensive, yet effective tool for the direct discovery of ore deposits. Case studies abundantly demonstrate that properties with viable mineralization and *proven reserves have been overlooked, forgotten. or ignored and can be rediscovered by inexpensive literature search techniques Areal studies s as WaIlaby Enterprises Mining District Data Base Program appear to be more effective than traditional commodity studies. The success of such studies depends on the inclusion of Mineral Clairant Questionnaire Data, Mineral Ownership Data, Field Examination Data and the continual updating of all information. Such studies are valuable for proposed or existing Wilderness Area Evaluations.

Jan 1, 1977

By M. F. Goodrich

The concept of using water-only cyclones as a clean coal scalping device preceding a heavy media cyclone circuit shows considerable promise, as it can considerably reduce the feed to the heavy media cyclone circuit. The system will not perform as well as a heavy media cyclone circuit alone, but the resultant loss in yield is small and may be negligible under some conditions. The concept of water-only cyclone scalping has previously been suggested by others. By reducing the amount of raw coal to be processed in the more expensive circuits overall capital and operating costs may be reduced. There are a few commercial plants with circuits operating on this concept. In the Warwick and Rowland plants water-only cyclones are used to scalp the feed to a heavy media vessel and Deister tables respectively while Amherst Coal Company's McGregor plant uses them to scalp the feed to a heavy media cyclone circuit. The system was evaluated on a technical basis, both from a theoretical viewpoint and by analysis of a computer simulation, in order to gain a fuller understanding of its usefulness and limitations.

Jan 1, 1977

By Edward J. McNamara

Sulphur as an element has been used for centuries. The technique of storing, handling and transporting it in its various forms has changed through the years. Freeport Sulphur Company, a division of Freeport Minerals Company, has produced sulphur since 1912. The first storing and transporting of this product as a liquid began in 1947. Significant environmental problems occurred in the handling of solid sulphur in the late fifties and early sixties. Since the sulphur WAS produced in the liquid form and the major customers used it in the liquid form, it became obvious that a liquid transportation system was the solution. The liquid sulphur delivery eliminated the dusty and hazardous handling problems and the contamination of the sulphur by dirt, acid, moisture and other materials. The remelting by the customer to use the sulphur is thusly eliminated with a savings in energy. In addition, this change in the mode of handling permitted a broad development of new sulphur mines in the marshy coastal area of Louisiana and offshore in the Gulf of Mexico.

Jan 1, 1978

By Douglas G. Fox

Outputs from industrial activities planned in the Riley Ridge natural gas project are modeled to determine the potential locations of air pollution impacts on the Bridger and Fitzpatrick Wildernesses in Wyoming. The nature of modeling, especially with regard to its realism, is discussed. Alpine lakes which, along with their watersheds, have minimal buffering capacity are being studied because of their sensitivity to acidic deposition from proposed new air pollution sources. A hypothesis which relates a source's emissions to deposition and lake chemistry in a worst-case sense is presented. Research designed to test the hypothesis and reduce uncertainties is outlined and progress reviewed. Focus is placed on the meteorological transport and atmospheric deposition parameterization contained in the hypothesis.

Jan 1, 1984

By Martin Langenderfer, Catherine Johnson, Alexander Douglas

Mine haul roads degrade rapidly due to extreme loads on suboptimal construction materials. Unmanned aerial vehicles (UAV) are suited to quantify large-area road-network conditions, such as surface roughness, defects and grade to optimize remediation of poor conditions and reduce overall costs. Mine haul roads present unique challenges, such as material type and edge characteristics, to automatic road detection that often fails, requiring manual road input. This research work proposes a new method using the road center determined by the principal curve of a haul truck’s path. Analysis grids were created from this center line. A dense point cloud from UAV photogrammetry was generated and multiple linear regression analysis was conducted on each individual grid. The root-mean-square error in each grid indicates the surface roughness, and the change of slope between grids indicates the road grade inconsistencies. This method was applied to 26 road sections, and the results were validated by images taken from the truck operator’s vantage point. Critical defects were identified including excessive pothole formation, corrugation, depressions retaining water, and narrowing of travel lane. The results demonstrate this is a valid method of road identification and quantification of road defects at a mine site.

Apr 1, 2024

By Zoltan F. Oszter

The frictional resistance to motion of a belt conveyor has always been a subject of intensive studies and research by engineers throughout the years. Numerous informations have been developed by analysing series of field tests on belt conveyors of different characteristics and carrying different materials at various capacities. Within certain limits of weight per unit length and tension, the theoretical considerations and the analysis of the field tests, both in the US and abroad, resulted in the development of similar formulas. In general these formulas are safe to use up to the following limits:

Jan 1, 1977

By Truman P. Stauffer

Secondary use of mined-out space in underground limestone quarries is emerging in the Kansas City area where abandoned quarry sites are being renovated into warehouses, factories, and offices. Mining techniques, ceiling heights, and pillar distribution are being altered as planning for the secondary use of mined-out space is combined with the quarrying process. Even the historic urban- quarry land use conflict invites a reappraisal in that this development provides a potential resolution of the problem. Mutual subsidization by dual rock and space interest is changing the economics of rock production. A city is much more than a surficial adjunct superimposed upon the topography of an area. Its development and growth are deeply rooted in the resources, benefits and problems of its underlying geology. The environmental geologist must address himself to more than the quality of a particular resource. He must comprehensively relate resource extraction and processing with the urban emphasis of optimal use which favors long term usage of land over one time economic ventures. Limestone quarrying, closely allied with the growth of many cities, has commonly left a series of scarred landscapes in the path of the burgeoning metropolis. These abandoned quarry sites are barriers to orderly city growth and fail to serve the people as useful and taxable land. Where quarries are functional, supplying the city with needed growth minerals, problems of blasting damage, noise, and dust exist. Technology faces the challenge of making mineral production and processing good neighbors to the urban market they serve. Continued growth of cities may require more efficient use of space below as well as above the surface optimizing land usage so that long term economic benefits may be reflected in improved mining methods.

Jan 1, 1973

By Steve Kral

The Clinton administration’s policies toward the environment have the mining industry on the defensive. The president and US Secretary of the Interior Bruce Babbitt continue to bypass Congress in their efforts leave an environmental legacy when they leave office in a year. So the mining industry must take its case to the public. And the public seems willing to listen if the industry is willing to tell its story, according to US Rep. Chris Cannon (R-UT). Cannon was one of the keynote speakers at the105th meeting of the Northwest Mining Association, in Spokane, WA. The conference, held in early December, attracted about 2,400 people and more than 200 exhibitors

Jan 1, 2000

By Gabriel Böde Jimenez Leon, Michael Karmis, Christopher Newman, Zach Agioutantis

"When utilizing high recovery underground mining methods, such as longwall or high-extraction room-and-pillar mining, the movement and deformation of the overburden propagate toward the surface and may affect the integrity of overlying surface streams (Peng et al, 1996). Published studies cite three major mechanisms of subsidence as most likely to impact streams: displacement, slope and strain. While subsidence-induced vertical displacement cause little structural damage to the stream bed, it may create adverse drainage and stream flow issues as the subsidence trough allows for ponding (Dawkins, 2003). Subsidenceinduced changes to the slope, or tilt, of a stream may have adverse effects on water flow. As the stream enters the subsidence trough, the gradient increases providing potential erosion control problems. When exiting the subsidence trough, a reduction of the gradient may inhibit stream flow, causing localized ponding (Peng, 2008). While vertical displacement and tilt both may have detrimental effects to surface streams, the resulting strains have been documented as being the most damaging to surface streams and structures causing distortion, fractures, or failure (Singh, 1992). When stream beds are subjected to high tensile strain, tensile cracks may form at the surface level allowing for the direct loss of stream flow through fissures. When stream beds are located in areas of high compressive strain, rock layers forming the stream bed can fail as the stream bed ruptures, upward, blocking stream flow or having the stream diverted into the fracture zone at the base (Iannacchione, et. al., 2010).Recent investigations on the effects of underground mining on surface bodies of water suggest that to determine the degree of stream impact one must also consider the geologic structure and thicknesses, surface topography, watershed drainage areas, width of river bed and rate of mining. Due to the complex nature and number of parameters affecting surface streams, subsidence modeling tools and software packages should be implemented throughout all stages of subsidence planning, prediction and control. The Surface Deformation Prediction System (SDPS) utilizes the influence function for the calculation of final subsidence deformations with respect to the angle of influence, supercritical subsidence factor as a function of the percent hard rock, edge effect offset distance, and surface topography. Developed more than 25 years ago, SDPS has been continually updated with new analysis and prediction features, providing a reliable and versatile program for subsidence management methodologies. Most recently, the program has been updated to evaluate the effect of varying surface topography in the prediction of horizontal displacements, referred to as ground strain, allowing for the accurate three-dimensional representation of surface deformations in mountainous terrain (Agioutantis and Karmis, 2014). Ground strain has become one of the predominant deformation indices used in the evaluation of potential damage to surface structures (Karmis et al., 1995). Ongoing work with SDPS software seeks to investigate the calculation of ground strain in SDPS and its ability to accurately and realistically predict damage to surface streams due to underground mining operations."

Jan 1, 2015

By S. Mojeddifar, N. Ostadmahdi Aragh, M. Hemmati Chegeni

This work integrated selective principal component analysis (SPCA) with a singularity fractal model to map hydrothermal alterations of argillic, phyllic, and propylitic in the north-west of Kerman city in Iran. SPCA results were provided for short wave infrared (SWIR) bands of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor tomap phyllic and propylitic alterations. Also, the bands 5–7 were applied to map the argillic alteration zone. SPCA results could present useful information for alteration mapping but it does not show the purest pixels of alteration. Therefore, a fractal model of singularity was applied to highlight the different alteration pixels in the Kerman Cenozoic magmatic arc (KCMA). Thus, the singularity index of different hydrothermal alteration zones was produced. Comparing the obtained results with the field data showed that Kader, Serenu,Meiduk, and Abdar deposits were acceptably identified by alteration mapping. Also, it seems that the singularity index could not discriminate the hydrothermal alterations of argillic and phyllic. The same spectral signature of kaolinite and muscovite minerals is the main reason for misclassifications.

Jul 20, 2020

By J. Noll, J. A. Organiscak, A. B. Cecala

"In recent years, significant strides have been made to optimize the design of filtration and pressurization systems used on enclosed cabs of mobile mining equipment to reduce respirable dust and other contaminants and provide the best air quality to the equipment operators. This synergetic effort has involved original equipment manufacturers building mining equipment, manufacturers of heating, ventilation, and air conditioning systems for mobile equipment, filtration and pressurization system manufacturing companies, as well as the National Institute for Occupational Safety and Health, and other government organizations. Considering all the advances made in this area over the last decade, one aspect that NIOSH still needs to assess is the longevity of optimal cab performance with respect to the quality (filtering efficiency) of the filters used in filtration and pressurization systems. In today’s culture, most health and safety professionals automatically believe that HEPA quality filters need to be used to provide the greatest level of protection to workers. Researchers at the Office of Mine Safety and Health Research for NIOSH hypothesized that HEPA quality filters may not be optimal for the mining industry and speculated that MERV 16 rated filters would be more appropriate in most cases. In order to test this hypothesis, NIOSH performed a two-year study comparing both HEPA and MERV 16 quality filters on two pieces of underground limestone mining equipment, being a roof-bolter and face drill machine. Testing showed at the 95 pct. confidence level that there was no statistical difference between the two efficiency filters on both pieces of mining equipment. Since the MERV 16 rated filters were less restrictive and provided greater cab pressure, and since they did not have to be replaced as often as the HEPA quality filters, researchers concluded the MERV 16 filters were the optimal choice for both pieces of mining equipment in this case study comparative analysis. INTRODUCTION When most health and safety professionals today think about filtration efficiencies and their correlation with protecting workers’ health, the normal assumption is the higher the efficiency of a filter, the greater the protection afforded to the workers. The next logical step is to believe that HEPA filters deliver the greatest protection for workers because they provide the highest filtering efficiency. Obviously high-efficiency intake filters are a necessity for an effective cab filtration and pressurization system on mobile mining equipment, but what is the optimal filter efficiency rating for achieving high levels of cab protection factor performance over the service life of filters? To address this question, the National Institute for Occupational Safety and Health (NIOSH) has performed an in-depth laboratory research study over the years simultaneously with numerous field studies to retrofit used enclosed cabs on mobile mining equipment with newer and more effective filtration and pressurization systems."

Jan 1, 2016

By S. P. Sandoval

In 2002 the Freeport-McMoRan Technology Center undertook research to develop a lower-cost alternative to guar for cathode smoothing in copper electrowinning. The work was conducted at the Technology Center?s SXEW Test Facility located in Morenci, Arizona. Bench-scale copper electrowinning cells were designed and implemented to screen a number of potential polymers for cathode smoothing. These included modified polysaccharide polymers that were nonionic, cationic, and anionic in nature.

Jan 1, 2010

By Steven A. Whittle, Robert E. Cook

Years ago, personal computers (PC) were pricey devices destined for who knows where in the process industry. Now their use runs the gamut from low end data acquisition systems to high performance windows into the process area. Their applications range from CAD, CAM, CIM, and CAE to factory floor scheduling, process planning QC, facility management, cell control, and publishing. This discussion traces the evolution of a zinc plant's control automation program beginning with a PC as an operator interface and migrating to higher level work stations. Included in this paper will be a discussion of an Open Industrial System and the role PCs have played in this facility.

Jan 1, 1993

By Richard L. Bullock

Believe it or not, mine evaluation and feasibility studies are as old as the industry itself. In the first recorded writing on mining by Agricola (1556), he gave several clues as what to look for in evaluating a mine, to determine if it was economically feasible. Below is the guidance from Agricola, with my interpretation of what he would include today. Now a miner, before he begins to mine the orebodies must consider seven things, namely: ? The situation (the geography/topography). ? The conditions (the geologic/mineralogic and mining conditions). ? The water (availability, hydrology and ownership). ? The roads (plus the railroads, power lines, all other infrastructure). ? The climate (the weather-rainfall/environment). ? The right of ownership (the land and legal entitlement). ? The neighbors (the social environmental concerns of the area). It is amazing how much of his guidance has not changed in 455 years. Yet Agricola gives no guidance on determining the correct cost, or determining the correct commodity pricing. But he does give a few words of caution on the related ethics involved on buying mineral properties: ?A prudent owner, before he buys shares, ought to go to the mine and carefully examine the nature of the vein, for it is very important that he should be on his guard lest fraudulent sellers of shares should deceive him.? Three hundred years later (1866), to further amplify this point, in the most famous thing that Mark Twain never said, as an introduction to a lecturer to an audience of gold-miners at Red Dog, CA, the famed author/humorist allegedly described a mine as ?a hole in the ground owned by a liar? (Farrar & Rinehart, 1935). So, one might conclude that between these two dates, the mining industry did little to improve its reputation. Unfortunately, since Mark Twain allegedly made those remarks, we have not done near enough to gain accountability for the mineral industry.

Jan 1, 2011

By R. W. Bruce

The normal practice for processing complex sulphide ore has been to grind with steel balls and/or rods in steel mills before flotation. Little thought had been given to the effect of grinding media on flotation selectivity of copper-lead -zinc ore until 1960 when Rey and Formanek(1) published their experiments on sphalerite floatability after grinding in a porcelain mill with ceramic pebbles. The studies by Rey and Formanek had a pronounced effect on the milling of copper-lead-zinc ores in Canada and possibly throughout the world at a time when autogenous grinding was creating a great deal of interest. The impression was created, and possibly still exists with some mill men, that grinding an ore in the absence of steel will result in a loss of selectivity between copper, lead and zinc minerals. This is in spite of the fact Rey and Formanek's experiments showed that the "naturall floatability" of sphalerite was not apparent after grinding in a porcelain pebble mill in an alkaline pulp.

Jan 1, 1976