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By F. C. Appleyard

As one of the more important Industrials Minerals, gypsum occupies a significant place in the economy of the United States, particularly in that segment which can be loosely called the Construction Industry. For many years, products made from gypsum have been a major building material, and the usefulness and versatility of these products is such that their widespread use is expected to continue. In 1968, according to U.S. Bureau of Mines statistics, the value of all gypsum products sold in the United States was 405,000,000 - and although this value has dipped from the 1964 high of $ 432,000,000, it is expected to trend upward in the next few years to equal and surpass this figure as the construction industry recovers from its current squeeze of "tight money" and high interest rates. There are many factors to be measured in determining the potential value of any mineral deposit, and how it might fit within its particular industry. What, then, are the qualities which a gypsum deposit must have in order to profitably participate in the four hundred million dollar plus business which is the gypsum industry? First let's consider the geology of gypsum, the geographic distribution of deposits, and the more important factors such as size, grade, capital requirements, and operating cost. Then, an understanding of the uses of gypsum, various types of products, and location of markets would be helpful, along with such other factors as the structure of the industry, price trends, etc.

Jan 1, 1970

By A. M. Raichur

Flocculation of fine coal is usually accomplished with the addition of commercially available organic flocculants. Recently it has been shown that biopolymers derived from microorganisms can be used to flocculate coal. The biopolymers flocculate coal efficiently and render the coal surface hydrophobic. The increase in hydrophobicity can be utilized either to separate the coal flocs from mineral matter. It can also be used for reducing the moisture content of fine coal. In this regard, flocculation and settling tests of fine coal with biopolymers and synthetic flocculants was undertaken and the results are discussed here. Also, a transport model was developed for the time-dependent settling tests for fine coal.

Jan 1, 1996

By Salvatore Fancello, Ferruccio Cribari, Amerigo Tanzi, Mauro D’Angelo, Massimo Lodico, Alessandro Bertero, Eliano Romani, Tommaso Gondolini, Fabio Giannelli

"The new metro line “C” entails the construction and rehabilitation of 24 stations and 21,5 km of metro line, 13 of which carried out underground; the new metro line will improve the transportation system of a congested city such as Rome.The new line “C” of San Giovanni metro station will be constructed adjacent to the existing line “A” of San Giovanni station; the new metro line “C” is deeper than line “A” and will underpass the existing station. The underpass project envisages an Artificial Ground Freezing in order to excavate two new tunnels, while keeping trains running in the safest possible condition.In order to allow trains to regularly run to and from the existing station’s line “A”, a temporary structure for rail support, during excavation of the under-crossing tunnels, was installed and a real-time monitoring system was devised in order to control both soil temperature during freezing activities and the existing station’s behavior. The monitoring system has been one of the key to the success of the project.The excavation of tunnels under the water table, with a hydraulic head of over 10 m in not homogeneous soils having different mechanical properties and permeability and below existing sensitive structures, involves special ground freezing sequences and methods, as well as peculiar drilling systems and operations, such as TDDT (Trevi Directional Drilling Technology).THE NEW “C” LINE OF ROME’S METROThe world’s most complex and extraordinary Metro System is currently being built in the heart of Rome. Its underground route stretches underneath the most important monuments, churches and historical buildings.Rome’s Metro Line C is the longest urban underground railway in Italy and it is the first line in Rome to extend further east to the Great Ring Road, thus bridging the gap between the farthest suburbs and the Historical Centre. It is an original project, carried out mostly underground at a depth of 25/30 metres below road level."

Jan 1, 2016

By Keith Whitworth

The USSR, over the last 20 years, has continued to increase its out-put year by year and it is now almost four times what it was at the end of the Second World War. In 1975, it exceeded 700 million tons of run-oi-mine coal (all ranks) which amounts to over 20 percent of world output. This rapid progress has been due to modernization of the industry, by means of increased mechanization and automation and the development of new machines and systems for underground workings and by the expansion of open-pit workings and the development and implementation of larger earthmoving machines.

Jan 1, 1977

By R. S. Olson

The operation of a series wash thickener-two stage filtration circuit determines the soluble loss in many hydrometallurgical operations A study of this circuit yielded expressions which permit calculation of soluble loss for almost any condition of operation. The soluble loss over a range of the circuit variables is presented to illustrate and evaluate circuit performance, The interrelation of factors affecting filter performance and some of the wash circuit, variables are quantatively described. Filter wash, which is governed by wash zone size, filter pulp level and filter feed pulp density, has the greatest affect on soluble loss. Excepting clothing blinding and flocculation the factors which decrease filter capacity also decrease soluble loss. Repulping with water, under some circumstances, can bean important means of soluble loss reduction. Water for primary filter wash, leach pulp density repulp density and wash thickener underflow density have little effect on soluble loss. The dilution of both o the filter pulps with wash solutions is suggested as a means of reducing soluble loss, and at the same, time, controlling the performance of the filters. Blowback and filter cloth blinding seriously increase soluble loss.

Jan 1, 1962

By Mahiyar Nasarwanji, Jonathan K. Hrica, Jonisha P. Pollard, Lydia M. Kocher, Brianna M. Eiter

Within the metal/nonmetal mining sector, fall-related incidents account for a large proportion of fatal and non-fatal injuries. However, the events and contributing factors leading up to these incidents have not been fully investigated. To help provide a clearer picture of these factors, an analysis of imminent danger orders issued by the Mine Safety and Health Administration (MSHA) between 2010 and 2017 at both surface and underground metal/nonmetal mine sites revealed that most orders are associated with fall risks. Of these cases, 84% involved the workers not using fall protection, fall protection not being provided, or the improper use of fall protection. Fall risks for workers most frequently occurred when standing on mobile equipment, performing maintenance and repairs on plant equipment, or working near highwalls. In most cases, a single, basic, corrective action (e.g., using fall protection) would have allowed workers to perform the task safely. Overall, these findings suggest that a systematic approach is needed to identify, eliminate, and prevent imminent danger situations. Furthermore, to protect mineworkers from falls from height, frequently performed tasks requiring fall protection should be redesigned to eliminate the reliance on personal fall protection.

By Laurence M. Demers, Douglas C. Kuhn

It has been suggested that radicals on the surface of dust particles are key chemical factors in the pathophysiology which results from the occupational inhalation of coal and silica dust. In addition, oxygenated derivatives of arachidonic acid (eicosanoids) have been implicated as important biochemical mediators of mineral dust-induced lung disease through their role in bronchial and vascular smooth muscle reactivity, inflammation, and fibrosis. Therefore, we assessed eicosanoid production by the rat alveolar macrophage (AM) exposed in vitro to mineral dusts with varying surface chemical characteristics in order to determine if radicals associated with the mineral dub1 could influence the production of pro-inflammatory mediators in the lung environment. Rat AM were exposed to freshly fractured or "stale" bituminous coal dust, as well as untreated silica or silica calcined to 500°C and 1100°C. Prostaglandin E2 (PGE2) and thromboxane B2 (TxB2) levels in incubation medium were determined by specific radioimmunoassay. When AM were exposed to freshly fractured coal dust, PGE2 and TxB2 production were markedly increased. In contrast, exposure of AM to "stale" dust significantly reduced PGE2 and TxB2 production. In vitro exposure of AM to untreated silica resulted in a significant increase in PGE2 and TxB2 production compared to control. However, exposure of AM to silica calcined to 1100°C resulted in eicosanoid levels which were not significantly different from control. These findings suggest that radicals associated with respirable coal and silica particles may play a key role in the ability of mineral dust to activate AM eicosanoid production.

Jan 1, 1991

By J. S. Meyer

Although salmonid fishes (including Pacific salmon and trout) have only intermediate sensitivity to copper (Cu) for traditional toxicity endpoints (survival, growth, and reproduction) and thus do not ?drive? the freshwater Cu criteria (e.g., see species-sensitivity ranking in US EPA 2007), Cu concentrations as low as 1 to 2 µg/L have been reported to impair olfaction (the sense of smell) in salmonids in laboratory experiments using dilute fresh water (see references in Meyer and Adams 2010 and DeForest et al. 2011). Olfaction is crucial to predator avoidance, recognition of kin, and reproductive synchronization (Baldwin et al. 2003); and Cu is of general ecotoxicological concern because it can be present in acid/mine rock drainage, industrial and municipal effluents, agricultural runoff, and urban stormwater runoff (Meyer et al. 2007). Therefore, there is public concern that the current regulation of Cu in surface waters is not stringent enough to protect salmonid fishes against olfactory impairment (e.g., OSU 2007; Pearson 2007). Because the toxicity of metals to aquatic organisms is a function of water chemistry [e.g., acute toxicity of Cu generally decreases as pH, water hardness (Ca2+ + Mg2+), alkalinity, and dissolved organic carbon (DOC) concentrations increase; Meyer et al. 2007], hardness-based freshwater criteria for metals are lower at lower water hardness. The recently-developed biotic ligand model (BLM) explicitly takes into account all four of those water chemistry parameters and the concentrations of other major inorganic cations (Na+, K+) and anions (Cl-, SO42-) to predict the acute toxicity of cationic metals (e.g., Ag, Cd, Cu, Ni, Pb, Zn) to aquatic organisms; and the BLM has been adopted by the U.S. Environmental Protection Agency (US EPA) to calculate acute and chronic national freshwater criteria for Cu (US EPA 2007). Consistent with observations of Cu toxicity to aquatic organisms, BLM-based Cu criteria generally are lower at lower pH, water hardness, alkalinity, and DOC concentrations. Therefore, although threshold concentrations for olfactory impairment by Cu can be low in dilute fresh waters, the corresponding hardness-based and BLM-based Cu criteria for the same waters also tend to be low. This leads to a logical question: Are Cu criteria already protective against impairment of olfaction in salmonid fishes, thus obviating the need to decrease those criteria even lower to protect against adverse effects to this physiological/ecotoxicological endpoint? Herein, we demonstrate that in all studies conducted to date, the US EPA?s BLM-based freshwater Cu criteria would have been protective against olfactory impairment in salmonid fishes, but the US EPA?s hardness-based criteria would not always have been protective. This distinction is important because all 50 States in the USA still use hardness-based Cu criteria in their water quality standards, and only some of the States allow use of the BLM to calculate site-specific Cu criteria. Additionally, in the absence of empirical results for calibration of a saltwater Cu-olfactory model, we demonstrate that a proposed unified freshwater-saltwater Cu-olfactory BLM predicts the US EPA?s current saltwater Cu criteria would be protective against olfactory impairment caused by Cu in sea water.

Feb 27, 2013

By John Kuyt, Zili Li, Michael Mooney, Michele Mangione

"INTRODUCTIONTwin bored tunnels are commonly used for a variety of road and tunnel projects throughout the world. A major component of these twin tunnel projects is the construction of connecting cross passages that provide emergency access between tunnels and space for tunnel service equipment. Cross passages can present significant geotechnical risk and technical challenges to a project – support systems must be considered for redistributing loads around the mainline tunnel openings and supporting new loading resulting from excavation activities. Additionally, cross passages pose risks to construction schedule and cost because of their sequencing at the end of construction, so mitigation of schedule overruns can be critical. By observing field instrumentation data records from completed projects, a betterunderstanding of the force development in each temporary structure can be achieved with indication of which structures are the most critical to support ground loads.This paper discusses the data obtained during the Brisbane Airport Link construction project, a road tunnel located in Brisbane, Australia. Strain gauge instrumentation data from the precast segmental lining and propped opening steel sets is presented with relation to the construction sequence and local geology. Interpretations and conclusions based on the observed trends are proposed, with several key mechanisms affecting the loading and unloading identified.Brisbane Airport Link Project OverviewThe Brisbane Airport Link project in Brisbane, Australia, connects central Brisbane to the airport located northeast of the downtown with over 7km of twin-bore road tunnels, two lanes each, with several caverns, interchanges, and access ramps constructed along the alignment to connect to other key routes in the city. The project was executed under a Public-Private Partnership (P3) scheme, funded and operated by the consortium BrisConnections. The main contractors were a joint venture of John Holland and Theiss, while the design was carried out by Arup and Parsons Brinckerhoff.Construction of the tunnels was conducted using a combination of 17 roadheaders and two 12.5m double-shield Herrenknecht TBMs [1]. The TBMs were used in EPB-type closed mode for the initial portion of their drive, starting at the northeast end of the alignment. Tunneling started in soft ground, weathered rock, and mixed face conditions initially, progressing to competent sedimentary rocks as the drive continued. Support was accomplished using a 12.1 m diameter steel fiber reinforced concrete (SFRC) segmental lining installed behind the TBMs in a 9 segments + 1 key arrangement. The innovative design of these segments is detailed in the paper by Harding and Francis [2]. Ancillary roads and underground interchange caverns were constructed by sequential excavation techniques using roadheaders, accounting for nearly half of the total underground excavations."

Jan 1, 2016

By James Wonneberg, William Edgerton

"Today’s underground construction megaprojects are tremendous feats of engineering on a massive scale, excavating through ground conditions once thought impossible, using new and innovative contracting practices. But one important truth remains unchanged; projects are built by people. What separates winning projects from the rest? Great people, working in great organizations. In straight-talk fashion this paper sets forth fundamental differences between good project leaders and bad ones, on topics ranging from client relations, design management, and scheduling, to use of the whiteboard, and everything in between. Broadly applicable to all corners of project delivery, this paper will resonate with project leaders from around the world and help identify skills necessary to succeed in the management of underground facilities. A NOTE FROM THE AUTHORS This is a training document, and not really a “paper” per se. We have attempted to tackle some big and potentially complex topics using bite-sized paragraphs, each of which are intended to promote thoughtful introspection and dialog. So please feel free to skip around, or even set this document down while you reflect on your own personal experiences, tactics, and philosophies. We have found that providing examples of “what not to do” is oftentimes more instructive than simply listing “what to do”, hence the Good/Bad format of this document. Please note that “PM” refers loosely to anyone on the project management team not just the “Project Manager”. We also wish to preface this with the following cautionary statements: • The authors do not pretend to be the “Good PM” in all cases. In fact, we’re almost certainly the “Bad PM” for some. We aim to improve on those areas. • It has been said that “The only real training for leadership is leadership.” (Antony Jay) We all started somewhere, and nobody has 20 years of experience on day one. • Converting this text into some sort of prescriptive checklist would be a disservice to the evolution of project management. Our world – and our awareness of it – is constantly changing. We must always be open minded to new ideas and different perspectives on project delivery."

Jan 1, 2016

By Cesar Carrasco, Heath Arvidson, Mark Forster

Block models built to represent the geology and rock characteristics of mineral deposits represent huge complex data sets, which form the basis of strategic and business planning, and public reporting of Mineral Resources and Mineral Reserves. Recent advances in cloud computing and database technology developed for the Internet of Things offer a different way of working with these critical data sets. Enabling a cloud based, open data structure with high performance data analytics capability presents a compelling improvement in governance and a democratization of ore body knowledge that can lead to automation use cases that support the digitalization of mining.

Jun 25, 2023

By W. F. Hahnert, P. A. S. Ralston

In off-line training of a rule-based controller, the significant measure of successful training is the quality of control provided by the generated rule set. In an adaptive or on-line control environment, performance is also measured by the ability to accurately maintain a satisfactory rule set, but within constraints on speed and/or resource availability. Very small population genetic algorithms, or microGAs, have been proposed as a means of capitalizing on the hill climbing characteristics of faster local optimization techniques while requiring less memory and retaining much of the robustness of traditional, larger population genetic search. A traditional genetic algorithm and a similar microGA are developed and applied to two control problems. The performance of these algorithms is analyzed with respect to (1) the quality of the rules learned, (2) the rate at which learning occurs, and (3) the memory resources required during learning.

Jan 1, 1993

By R. A. Haney

The Mine Safety and Health Administration (MSHA) has conducted studies both in coal and non-coal mines to evaluate methods for sampling diesel particulates in underground mines. The agency is investigating size separation techniques to distinguish between diesel particulate and respirable coal mine dust. Additionally, ashing techniques have been used to distinguish diesel particulate from mineral dust in metal and non-metal mines. As part of these studies, personal exposures to diesel particulate for various mining occupations have been measured. This paper describes the measurement techniques and summarizes the exposure levels for various underground mining operations.

Jan 1, 1993

By Frank Cook

As in other areas of the country, surface coal mine productivity in the Central Coal Province--primarily Illinois, Indiana, and west Kentucky--has declined steadily since 1969 (figure 1). Productivity, as measured in tons of clean coal produced per man-shift, dropped 35 percent during the period 1969-1975. Unwelcome at any time, this phenomenon is particularly untimely now, when increased coal production is a national goal. The U.S. Bureau of Mines has been working with the coal industry to develop new operating methods and equipment to enable increased productivity and improved reclamation performance in surface coal mining. Several projects have involved identification and evaluation of existing overburden handling and reclamation practices, and development of means to improve operational procedures. Some results of one of those projects, as they apply to the Central Coal Province, are summarized in this paper.

Jan 1, 1977

By Haydn H. Murray

A hydrothermal bentonite located in the high Sierras in Nevada is being mined and processed to produce a natural dietary supplement. The minerals present are smectite, gypsum, jarosite, quartz, feldspar, kaolinite, goethite, hematite and zeolite. The clay material was analyzed for respirable crystalline silica, asbestiform minerals, heavy metals and dioxin. No asbestiform minerals are present and the crystalline silica, heavy metals and dioxin are all less than the maximums set by Federal and State agencies. The clay material was analyzed chemically for all major, minor, trace and rare earth elements. The geology, applications and analyses will be discussed in the paper.

Jan 1, 2005

By Andy W. Stephens, William H. Langer

In Australia and America, encroachment by conflicting land uses, zoning restrictions, and the "not in my backyard" syndrome make it increasingly difficult to access high-quality aggregate resources located near the market areas. Attempts by government agencies in America to protect aggregate resources for future development have met with varying degrees of success. The State of Queensland, Australia, designates aggregate resource areas as Key Resource Areas, which protect the resource and the routes to transport the resource, provide a separation area from incompatible land uses, and indicate the likelihood that the area is free from conflicting social or environmental issues.

Jan 1, 2005

By W. D. Diment

The concept of flying employees in and out of remote mine sites on a regular rotation basis, rather than establishing permanent support communities nearby, has gained increasing acceptance by mine operators, unions and regulatory agencies in Canada. The development of successful fly in/fly out programs and resultant compressed work schedules is dependent on meeting design requirements through comprehensive research of worker profiles to ensure the selection of suitable employees and the implementation of satisfactory working conditions. This paper presents an overview of Canadian mine industry practice with regard to the fly in/fly out mode of operation and compressed work schedules.

Jan 1, 1987

This one day field trip is sponsored by the Denver Region Exploration Geologists? Society, May 14th 2009. The trip highlights major geologic features and some notable uranium occurrences along the north-south mountain-basin boundary southwest of Denver and continuing north to Fort Collins, Colorado. Uranium deposits visited include sandstone?hosted roll front type and polymetallic veins hosted in metamorphic rocks. A replacement ?episyenite? type occurrence is considered via description and hand samples but is not visited owing to logistical constraints. Recovery methods addressed include underground mining and in-situ leach recovery. Samples of Precambrian basement rocks, deposit host rocks, uranium ore samples, and ore polished sections viewed by reflected light microscopy will be available. A road map showing the locations of the stops serves as the front cover of this field guide. The Robinson episyenite-hosted occurrence (not visited) is labeled as Stop 6. A stratigraphic column is provided which shows the position of the host rocks at each stop (Figure 1-1).

Jan 1, 2009

By Erik Klohn

The El Soldado copper deposit occurs in volcanic rocks of alkaline affinity of Lower Cretaceous age. The orebodies are discordant and show strong structural and lithological control. The mineralizing event was accompanied by hydro- thermal alteration expressed as carbonatization, silicification, and chloritization. Individual orebodies contain bornite-chalcopyrite cores which are surrounded by haloes dominated by chalcopyrite and pyrite respectively. The sulfur isotope composition of copper sulfides strongly suggests the sulfur is of magmatic origin. Fluid inclusion studies show the mineralizing fluid to be a highly saline NaC1-CaC12, brine. No evidence of boiling was found. The deposit is most likely of epigenetic origin. Hydrothermal fluids were produced during crystallization of a sodium rich trachytic magma during the waning stages of an episode of alkaline magmatic activity. Similar copper deposits along the Chilean Coastal Range may also be associated with alkaline host rocks.

Jan 1, 1986

According to the Balandin's (1) "multiplet theory of catalysis", adsorption can occur only if atoms of the reactant molecules are congruent with surface atoms of the catalyst. Such a condition calls for certain definite geometrical relationships between the reactant molecules and the atoms at the surface of the catalyst. If such a match or geometrical 'fit' is not provided, the surface reaction will not take place. An appropriate analogy to this may be the lock and key theory that enzymes should fit a substrate just as a key fits a lock. Similar geometrical considerations in adsorption studies were made in connection with the flotation of minerals. Gaudin(2) and Gaudin and Preller (3) proposed that if the dimensions of collector ions are in registry with the mineral lattice, an ordered layer of adsorbed species is formed. They explained that the structural fit is one reason for good flotation of galena with xanthate. In another study, Bachmann (4) attributed the selective flotation of KC1 from NaCl with amine to the fact that the lattice parameter of the amine collector is closer to that of KC1. Schubert(5) investigated the flotation of various nonmetallic minerals with amine and pyridine, and related the dimensions of the collector ions with the anion distances of the mineral surface. He concluded that good flotation is obtained when the tolerance is within 20%. The geometrical theory has also been used by Groszek (6) to explain the preferential adsorption of n-paraffin onto the basal plane of graphite. The geometrical theory has thus been found useful in explaining adsorptive properties of an adsorbate relative to the substrate structure. The purpose of the present work is to examine the possibilities of a geometrical fit between sodium dodecyl sulfate and Cu(OH)2 surface, and to construct a crystallographic model of the surface compound.

Jan 1, 1974