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By D. K. DeForest

The olfactory system (sense of smell) is crucial to the ability of fish to avoid predators, recognize kin, and synchronize reproduction (Baldwin et al. 2003). Copper (Cu) has been shown to impair olfaction in juvenile freshwater life stages of salmonids (including Pacific salmon and trout) in some laboratory experiments; and in the United States, public concerns have been expressed that current regulatory criteria for Cu in fresh water are not adequately protective of olfactory function in salmonids (e.g., OSU 2007; Pearson 2007). These concerns have largely been raised because some Cu concentrations that have caused olfactory impairment in salmonids in the laboratory are less than Cu concentrations that have been shown to reduce salmonid survival, growth, or reproduction (the effects endpoints that are typically considered in deriving ambient water quality criteria). However, two important and interrelated points that must be considered: (1) freshwater Cu criteria are "driven" by the sensitivities of several invertebrate species that are more sensitive than the olfactory impairment threshold in salmonids when (2) the influence of water chemistry on Cu bioavailability is properly considered in deriving Cu criteria. Bioavailability refers to the ability of various chemical forms of Cu to interact with receptors on the surface(s) of organisms and thus directly cause toxicity or uptake by the organisms. The toxicity of Cu and other metals to aquatic organisms is a function of water chemistry. For example, acute Cu toxicity in fresh water generally decreases as pH, water hardness (Ca2+ and Mg2+), alkalinity, and dissolved organic carbon (DOC) concentrations increase (Meyer et al. 2007). The U.S. Environmental Protection Agency (USEPA) has recommended hardness-based freshwater aquatic life criteria for Cu and other metals since the 1980s (e.g., USEPA 1985); and hardness-based metals criteria decrease (i.e., become more restrictive) as water hardness decreases. More recently, the USEPA has recommended freshwater aquatic life criteria for Cu based on the biotic ligand model (BLM; USEPA 2007), which accounts for the influence of multiple water chemistry parameters, including DOC, pH, alkalinity, Ca2+, Mg2+, and several other cations and anions. The BLM-based Cu criteria generally decrease as DOC concentration, pH, alkalinity, and water hardness decrease. Because DOC has a stronger influence on Cu bioavailability than water hardness, hardness-based and BLM-based Cu criteria can differ considerably. For example, in water that has low DOC and high hardness, the hardness-based Cu criterion would be relatively high (because it is driven by the high hardness) but the BLM-based Cu criterion would be relatively low (because it is driven by the low DOC). Thus, any evaluation of the protectiveness of Cu criteria against a given effect, such as olfactory impairment, must properly account for the chemistry of the exposure water. Meyer et al. (2013) compiled data on Cu-induced olfactory impairment and olfactory-induced behavioral effects from tests in which BLM parameters were measured. They demonstrated that the USEPA's BLM-based freshwater life criteria for Cu are protective against olfactory impairment, because it adequately accounts for water chemistry (whereas the USEPA's hardness-based Cu criteria are not consistently protective). Olfactory impairment by Cu is now receiving increased attention in Canada and Europe (e.g., Wall 2013; Stang 2013). Accordingly, in this paper we have expanded the analysis of Meyer et al. (2013) to consider copper guidelines from various other countries and whether these guidelines are protective against olfactory impairment.

Feb 23, 2014

By Kurt Wiener

A major process control system is in some ways like a complex organism. The extremities, (that is, field instruments) are exposed to many hazards and suffer malfunctions of relatively minor and repetitive nature. Here I equate a stuck valve or dead transmitter with a skin abrasion or cut. The maintenance and repair of the extremities can be done by technicians with basic but thorough knowledge of relatively few problems and their solutions. Here I equate with administering Band-Aids and aspirin. On the other extreme, when the master control device (such as a computer) fails, one does not attempt home remedies. A "brain" specialist is called in. It is, however, crucial that the patient be able to clearly describe his symptoms. Getting down to the case at hand, a complex system consisting of field instruments, instrument racks, interface equipment, and perhaps a computer, may require maintenance at all levels. At the field equipment end where physical damage, corrosive atmospheres, reconfiguration, and routine calibration checks are common, the customer has the opportunity to develop a competent staff of maintenance people. The relatively high maintenance activity assures competence through repetition.

Jan 1, 1980

By R. E. Cook

"Mineral deposits require substantial amounts of energy to transport and be processed into useable form, and as such present a real processing challenge in that the deposits are never homogeneous and ore body compositional characteristics are all over the map! Extracting the desired mineral(s) from the deposit at sufficient profit margin, despite severe fluctuations in market price, requires process automation architecture capable of supporting an integrated enterprise solution. Such an architecture will encompasses the activities of individuals, process units, process areas, plant level activities, mine management and business planning and accounting systems. Key to the automation process is the aspect of value generation. This paper brings together the various requirements for the automation of a mining enterprise and presents the different aspects of how to obtain value across the entire mining operation.INTRODUCTIONMinerals’ processing sites are historically long lived, 20 year life of mine is not uncommon and 75 years is not unheard of. Considering that hardware technology advancements are introduced every six months, or less, it is prudent to select process automation systems that adhere to “open” industrial standards versus proprietary based systems. In the minerals processing industry, the key to survival is driving the cost of production per unit volume to the lowest possible level and provide enough profit to sustain operations. Control system architecture and Business information technology are rapidly becoming important tools in the quest for productivity. Getting key dynamic business performance information at the right time to the right person or process unit is crucial to successfully achieving corporate goals. The process automation architecture selected must therefore be able to integrate to the various networking enterprises and business systems.The mining industry is generally known as an “extractive” industry that is very physically-oriented with respect to operations and the activities in which workers engage. Large numbers of people performing manual tasks in difficult surroundings, produce very variable outputs. But, times are changing – and so are industry best practices. While the nature of work still consists of activities such as ore extraction, ore movement, ore concentration, refinement and logistics, automation innovations are starting to change the nature of many of the production steps. The industry has transitioned from requiring more physical activities by workers, to more information management, automated control and collaboration within the operation. Humans are good at situational intervention and non-linear reasoning and do best when empowered with an overall production perspective. Machines and automation are good at repetitive functions, steady state operation, and managing transitions. Thus, a combination of advanced technology solutions, reliable and useful information and full human contribution are necessary to mining operations for value generation."

Jan 1, 2015

By R. E. Cook

"Mineral deposits require substantial amounts of energy to transport and be processed into usable form and, as such, present a real processing challenge in that the deposits are never homogeneous and orebody compositional characteristics are all over the map. Extracting the desired mineral(s) from the deposit at sufficient profit margin, despite severe fluctuations in market price, requires process automation architecture capable of supporting an integrated enterprise solution. Such an architecture will encompasses the activities of individuals, process units, process areas, plant level activities, mine management and business planning, and accounting systems. Key to the automation process is the aspect of value generation. This article brings together the various requirements for the automation of a mining enterprise and presents the different aspects of how to obtain value across the entire mining operation.Minerals’ processing sites are historically long lived, with 20-year life-of-mine not uncommon and 75 years not unheard of. Considering that hardware technology advancements are introduced every six months, or less, it is prudent to select process automation systems that adhere to “open” industrial standards versus proprietary based systems. In the minerals processing industry, the key to survival is driving the cost of production per unit volume to the lowest possible level and provide enough profit to sustain operations. Control system architecture and business information technology are rapidly becoming important tools in the quest for productivity. Getting key dynamic business performance information at the right time to the right person or process unit is crucial to successfully achieving corporate goals. The process automation architecture selected must, therefore, be able to integrate to the various networking enterprises and business systems.The mining industry is generally known as an extractive industry that is physically oriented with respect to operations and the activities in which workers engage. Large numbers of people performing manual tasks in difficult surroundings, produce variable outputs. But times are changing – and so are industry best practices. While the nature of work still consists of activities such as ore extraction, ore movement, ore concentration, refinement and logistics, automation innovations are starting to change the nature of many of the production steps. The industry has transitioned from requiring more physical activities by workers to more information management, automated control and collaboration within the operation. Humans are good at situational intervention and nonlinear reasoning and do best when empowered with an overall production perspective. Machines and automation are good at repetitive functions, steady state operation, and managing transitions. Thus, a combination of advanced technology solutions, reliable and useful information and full human contributions are necessary to mining operations for value generation."

Jan 1, 2015

By R. A. Hodge, J. W. Murray

By an order of the Executive Council of the Provincial Government dated January 18, 1979, a Royal Commission was established under the Public Inquiries Act to: 1) Examine the adequacy of existing Federal and Provincial requirements for the protection of the health and safety of workers associated with exploration, mining and milling of uranium in B.C. and for the protection of the environment and of the public. 2) Receive public input on these matters. 3) Make recommendations for setting and maintaining standards for worker and public safety and for the protection of the environment as a result of the exploration for the mining and milling of uranium ores. At that time,and at the present time in British Columbia, no uranium mines were, or are, in operation. Exploration at a number of sites was under way and one deposit, the Blizzard deposit, with estimated reserves of 1.92 million tonnes containing approximately 4.74 million kilograms of U308 was at an advanced stage of exploration. With our Terms of Reference, and because of the diverse geology of the western Cordillera which could potentially host a broad variety of uranium, deposit types, the Commission was faced with the task of considering environmental and health protection necessary for the potential development of [any] kind of uranium mineralogy situated in [any] of the environments found in British Columbia. Over the past 17 months since that time, much has transpired, culminating in the February 27, 1980 Provincial Government announcement of a seven year moratorium on exploration, mining and processing of uranium coupled with the termination of our Inquiry before completion of the hearings. The Government sebsequently modified its decision to terminate the Commission completely, deciding instead to stop the hearing but allow time for the Commission to gather in the work that had been initiated

Jan 1, 1980

By Roberto de Moraes

Lunar construction faces unique challenges arising from the nature of regolith and megaregolith. Unlike terrestrial soils shaped by weathering, lunar regolith is composed of angular, poorly sorted particles produced by impacts, with bulk Density, strength, and trafficability varying sharply with depth and terrain. Boulder fields, floaters, and talus aprons add further complexity, disrupting excavation and mobility. Apollo missions documented these conditions through drive-tube samples, trenching, penetrometer data, trafficability tests, and seismic profiling, but the results remained as datasets rather than a unifying classification. This paper introduces the LRC (Lunar Regolith Classification) Framework and the Overconsolidation Ratio applied for the Moon (OCR*), the first contractor-ready system to organize Apollo-derived trends into excavation demand zones (L1–L5). LRC is explicitly a classification, not a stratigraphy: depth ranges are indicative and require in-situ verification before use. Each zone is defined by bulk density and strength ranges, field proxies (bootprints, trench stability, auger torque, seismic contrasts), and corresponding excavation implications. Worked examples from Apollo 15 (mare), Apollo 16 (highlands), and Apollo 17 (pyroclastics and talus) demonstrate how observed data translate into LRC zones. These cases show that LRC captures both systematic depth trends and sharp local heterogeneity. The framework standardizes excavation planning for landing pads, haul roads, berms, foundations, and tunneling trials, while converting floaters from hazards into resources. LRC thus provides a common language for lunar construction. Rooted in Apollo evidence but designed for Artemis verification, it is proposed as a living standard; a reference framework to guide site preparation, excavation, and risk management in the next phase of lunar development.

Feb 22, 2026

By J. P. Ducarme, J. L. Carr, C. C. Jobes

"An average of 1.2 fatalities occur per year in underground coal mines in the United States when a miner is struck or pinned by a remote-controlled continuous mining machine. Proximity detection technology provides a means to prevent these types of accidents by disabling all machine motion when a miner is in close proximity. Researchers at the National Institute for Occupational Safety and Health (NIOSH) have developed the intelligent Proximity Detection (iPD) system, which continuously tracks the position of miners near the machine and disables only those machine motions that could cause a pinning accident. This system, previously demonstrated using non-permissible proximity detection hardware, has now been shown to be effective when implemented using an MSHA-approved system as a platform. Performance tests have shown accuracy, repeatability, and stop zone identification to be comparable to or better than the system demonstrated with non-permissible hardware. INTRODUCTION Underground coal mining room-and-pillar operations typically use Continuous Mining Machines (CMMs), such as the one shown in Figure 1. When CMMs first became available, they were operated from an on-board operator’s compartment that protected operators from roof falls and other hazards but severely restricted visibility and subjected them to machine vibration and high levels of dust and noise. To solve these problems, remote controls were developed to operate CMMs. Now CMM operators are free to position themselves for best visibility of each mining task and are no longer subjected to the rough motion of the CMM during mining operations or the dust and noise generated by the machine. However, this technological advance removed operators from the protection afforded by the operator’s compartment and exposed them to the hazard of being struck or pinned by the CMM or other large moving machines."

Jan 1, 2015

By T. W. Camm

"Search Amazon.com using the keyword “leadership,” and you are rewarded with a list of over 144,000 titles. There is no shortage of books and articles, many of them well written, with excellent ideas. So why is there still a constant cry for effective leadership in organizations? Often, the person in charge has personal blinders that prevent them from seeing or understanding how to implement the newest leadership idea or method. Either deliberately or subliminally, there is a disconnect from learning about leadership, and actually modelling and implementing what has been learned. Some current research in leadership theory can provide insight and tools to address this issue. INTRODUCTION Let’s start with a discussion of terms. Pseudo is defined by Webster (2015) as “Being apparently rather actually as stated.” Synonyms include affected, assumed, contrived, fake, false, phony, pretended, and artificial. Antonyms for pseudo provide additional clarity, especially when we consider terms normally associated with effective leadership: genuine, natural, unaffected, unforced. A similar type from my world of academia is a pseudointellectual, “A person exhibiting intellectual pretentions that have no basis in sound scholarship” (Dictionary.com, 2015). This is a person pretending to have an interest in intellectual activities for status; a fraudulent intellectuality. The thought of applying the term pseudo to leadership first occurred to me while reading Power and Innocence by Rollo May (1972). In discussing the dynamics of power, and how the innocent are often victims of the exercise of power, especially the more aggressive and destructive types of power, he saw two types of innocence. The first he called authentic innocence, which he described as a childlike clarity that carried into adulthood. The second type he called pseudoinnocence, a type of naïveté that makes a virtue of powerlessness, weakness, and helplessness; being more childish than childlike (p. 48-50). Just as there is the potential for pseudoinnocence and pseudointellectuals, it is also possible to experience pseudo leadership. (I hope the gentle reader is not troubled by my decision to use pseudo leadership as two separate words, in contrast to the use of compound words for pseudoinnocence and pseudointellectual cited above. Since there is no official definition of pseudo leadership, I have exercised my author’s prerogative to treat it as two words, both because I think in this particular application this makes the most sense, and also I think it is easier to read). As we will see, there are numerous theories applied to leadership. What is so troubling to many of us in organizations, there are a myriad of “leaders” in companies espousing pet theories, but very few instances where the actions of these individuals match their words. This is a particularly important problem when we look at the effect this has on the day to day operations of a mine, and where effective leadership (or its absence) can have a profound impact on both productivity and safety."

Jan 1, 2016

By R. Freer

Recent developments in expanded PTFE membrane filter cloths offer high flow rates and sub-micron particle removal. These high strength, industrial grade filter cloths can be tailored for tubular filters, leaf filters and rotary vacuum drums. Filtration techniques using tubular filters make possible filtration of difficult slurries with the elimination/reduction of filter aids and chemical additives. This paper describes principles of surface filtration, applying the membrane filter cloth and comparisons to gravity separators. Benefits to the mining industry include clear effluent, enhanced solids recovery and accelerated cost payback.

Jan 1, 1996

By Roger L. Baer

Introduction Brief Review -SEC mission & history -Development of SEC mining disclosure guidelines -Principles of good public company ‘disclosure’ SEC staff views of alternative approaches to mining company disclosure -SME Resource & Reserve Committee – April 2003 Food for thought

Jan 1, 2003

By Michael Karmis, Emily A. Sarver, Ellen S. Gilliland, Leigh-Anne H. Krometis

"Public engagement is increasingly important in ensuring the success of projects related to energy development, particularly with regard to issues of environmental protection, public health, and socio-economic impacts. This is due to concurrent trends in public behavior, including a rise in public interest in these projects that is not matched by a rise in science literacy, and increasing organization and participation of the public through social media, citizen science, and grassroots initiatives. In recent years, several high-profile incidents have demonstrated that when public concern is ignored or met with a passive response from industry, it can rapidly grow into organized opposition that negatively impacts or wholly derails a project. Engaging, listening to, and educating stakeholders during early planning and development phases are therefore essential to earning credibility and trust. Moreover, maintaining two-way lines of communication throughout the lifespan of a project demonstrates social responsibility and facilitates cooperation, acceptance, and even support from communities and others. Positive experiences with specific projects at a local, community level can influence the larger public opinion of an entire industry sector. This paper presents cases studies of public engagement related to shale gas development (including hydraulic fracturing and pipeline construction), mountaintop removal mining, and management of mixed-use watersheds near surface mining operations. The experiences highlighted in these case studies are used to draw best practices of public engagement for sustainable energy development.Introduction Within the scientific research community, the importance of public engagement has gained increasing recognition. In a 2007 article in Nature, medical researcher, Patrick Taylor, stated that public engagement has both “gone viral” and “gone global” and has the ability to make real impacts to research (Taylor 2007). Nancy Baron, the science outreach director for COMPASS, an organization providing communications training for scientists, provides further evidence for the increasing focus on engagement, including shifting attitudes observed during her own experience as a communications coach and documented in surveys, the recent inclusion of communication and engagement activities in academic tenure review, and the surge of workshops, materials, and other resources available on the subject (Baron 2016). In addition to COMPASS, a number of organizations and institutes have been developed to train scientists for communication and engagement with the public, perhaps most notably the Alan Alda Center for Communicating Science at Stony Brook University, and academic fellowship programs, such as the Leopold Leadership Program at Stanford University and the Wilburforce Fellowship Program, have been established for the same purpose."

Jan 1, 2017

By F. J. Brenner

The Slippery Rock Watershed Coalition was organized to restore a 70 km2 portion of the headwaters of the Slippery Rock Watershed in northwest Pennsylvania. Thirteen passive treatment systems have been installed with engineering and funding provided by private industries, county government and the Commonwealth of Pennsylvania. In addition, experimental systems have been installed at the Jennings Environmental Education Center which, in addition to monitoring the systems installed within the watershed, provide an array of educational and research opportunities for secondary, college and university students. The coalition sponsors an annual seminar for students to present the results of their research and field trips for public officials and private citizens to learn how public and private partnerships work together to restore the Slippery Rock Creek watershed.

Jan 1, 2002

By John B. Rigg

The title of my paper today is "public relations challenges for the pending minerals crunch". There isn't anyone in this room who would dispute. That the minerals industry has always had public relations challenges . . . No matter what the circumstances, mineral shortage or abundance. The industry suffers from an image that is second to none in longevity. It defies all actuarial formulas of the past or the future. Never mind that such an image is outdated, distorted, overstated, and reiterated. I submit that the minerals industry had public relations challenges long before there was anything called public relations. This account of egyptian mining practices, recorded for posterity by Diodorus Suculus at the end of the second century, b.c., is indicative. "On the confines of Egypt . . . And Ethiopia is a place which has many great mines of gold, where the gold is got together with much suffering and expense. The kings of Egypt collect together and consign to the gold-mines those who have been combined for crime, and who have been made captive in way . . . Sometimes only themselves, but sometimes likewise their kindred. "Those who have been consigned to the mines, being maw in number and bound with fetters, toil their tasks continuously both by day and all night long, getting no rest and jealously kept from all escape.

Jan 1, 1975

By S. James Campbell

Ladies and Gentlemen: Never in the history of our mining industry has the emphasis on public relations been accelerated as much as it has in the last few years. Knowing of your keen interest in this subject I consider it a great privilege that your program committee has asked me here to discuss the crushed stone segment of our industry approach to this important part of our daily business lives. As you are aware, crushed stone operations are present in almost every segment of the country wherever aggregates for construction projects are required. The tonnage of crushed stone produced is second only to sand and gravel - another source of aggregates - and this together with sand and gravel amounts to over half of the tonnage of all mined products in the United States. What is unique about this industry that will be of interest to all of you in analyzing how they have approached Public Relations? The fact that it is so wide-spread is of course obvious, but perhaps a more significant nature of this segment of the mining industry that has brought it more in the limelight of public interest and on a larger scale is the location of a large part of the quarries quite close into the urban area and population centers where you have the greatest demand for aggregate products.

Jan 1, 1969

By David R. Cole

Before discussing some of the specific public relations issues in Colorado mining, I would like to define public relations, identify the "publics," review Colorado's population profile, and outline Colorado's mining history. Public Relations In describing public relations, a definition which is frequently quoted appeared in the PUBLIC RELATIONS NEWS, and is as follows: "The Management function which evaluates public attitudes, identifies the policies and procedures of an individual or organization with the public interest, and executes a program of action to earn public understanding and acceptance..' As you can see, this covers a "multitude of sins."

Jan 1, 1975

By Mike O’Brien, Rob Croll

The Evolution of AngloGold -Incorporated in 1944 under the name of Vaal Reefs Exploration and Mining Company Limited -Name changed to AngloGold Limited in 1998 as the vehicle consolidating the gold interests of Anglo American Corporation -Diversification (geographic and orebody) through the sale of low-margin, deep level, short-life assets and the acquisition of higher margin, open-pit and shallow underground operations

Jan 1, 2003

By M. H. Dunn, T. P. Danehy, C. F. Denholm, S. L. Busler

The problems associated with abandoned minelands are so extensive that neither federal, state, or local governments nor the mining industry nor watershed groups can adequately address these problems individually. By combining talents and resources, however, these problems are being solved efficiently, effectively, and economically. Utilizing existing water monitoring data, local public-private partnerships have successfully designed and built passive systems within five weeks to six months which treat discharges up to hundreds of gallons per minute that vary in quality from net alkaline to highly acidic, containing as much as 200 mg/L dissolved iron and 70 mg/L dissolved aluminum.

Jan 1, 2002

By F. Grandjacques

INTRODUCTION Selective Reduction of Nickel in Oxidized Ores Oxidized nickel ores, either garnieritic or lateritic, contain much more iron than nickel. The regular carbon reduction in an electric furnace is operated in such a manner that the greater part of iron oxides is reduced simultaneously with nickel oxide, resulting in a low nickel content ferronickel. In order that the nickel content of residual slag may be suitably low, -excess carbon must be fed so that the carbon content of the ferronickel thus obtained is that of casting iron. The metal also contains other impurities such as silicon, chrome, etc. In order to convert the casting iron into slightly carburized ferronickel with high nickel content, the greater part of the carbon and more than half the iron contained therein must be oxidized by means of oxygen. Energy is thus consumed as carbon, and power to reduce iron oxides, and more energy is consumed as oxygen to re-oxidize the iron contained. This method can be economically adopted for nickel ores with grades ranging around 2. 5 to 370, but it gets excessively costly when nickel grade falls below these values. This is why, for nickel ores with low nickel grades and high iron content, studies were conducted to develop a selective reduction process which, while reducing only a small part of the iron oxide, would provide efficient reduction of nickel oxide. Rich ferronickel is thereby obtained, with nickel content ranging around 30 to 50%. Due to the presence of slag with a high iron oxide content, the metal thus

Jan 1, 1979

By William E. Wallace, Michael J. Keane

This review summarizes three sets of ongoing studies which we are performing in collaboration with a number of researchers associated with the Dept. of Interior - Generic Mineral Technology Center for the Study of Respirable Dusts, concerning surfactant-particle interactions studied using this surrogate surfactant. These topics are: (A) the suppression of mineral particle cytotoxic potential by DPL adsorption and the persistence of this effect under conditions of enzymatic digestion; (B) surfactant suppression of organic particle cytotoxicity by DPL adsorption and the effect on subsequent expression of genotoxic potential; (C) potential effects of surfactant on heterogeneous structured complex respirable particles. The references list some of our reports which can provide additional information on these studies. Further, those reports provide references to the literature of the field and to the works of others on these topics. Deep lung airspaces, the pulmonary alveoli and respiratory bronchioles, are coated with a hypophase which is rich in surfactant biomolecules secreted by the alveolar type II epithelial cells. The surfactant is known to be critical to maintaining stable low surface tensions on the inner surfaces of the alveoli by forming a surfactant layer on the airliquid interface of the alveolar hypophase. Upon deposition in the acinar regions of the lung a respired particle's initial contact will be with this surfactant coating over pulmonary tissue. A primary component of this surfactant is the phospholipid diacyl glycerophosphorylcholine, commonly called lecithin. A surface layer of dipalmitoly lecithin on saline will act much as full pulmonary surfactant in decreasing surface tension and producing a hysteresis in surface tension behavior with surface area. We have used dipalmitoyl glycerophosphorylcholine, or dipalmitoyl lecithin (DPL), a major component of that surfactant, dispersed in physiologic saline as a surrogate for studying interactions of both mineral and organic respirable particles with pulmonary surfactant and consequent effects on particle toxic behavior. A. DUST CYTOTOXICITY AND LECITHIN SURFACTANT ADSORPTION Respirable quartz and kaolin clay particles are found to be comparably cytotoxic in a number of in vitro bioassays including lavaged rat pulmonary macrophage release of cytosolic and lysosomal enzymes, and red blood cell hemolysis as a measure of dust membranolytic potential. These direct and prompt cytotoxic activities do not account for the distinctly greater potential for quartz to induce pulmonary disease. When respirable quartz and kaolin are incubated with a dispersion of DPL in saline at 37C it is found that the prompt cytotoxicity of both dusts is fully suppressed as measured in vitro by pulmonary macrophage release of lactate dehydrogenase, beta-N-

Jan 1, 1991

By K. S. E. Forssberg, K. Hanumantha Roa

Batch flotation tests are carried out with phosphatic material from LKAB, Sweden containing carbonatic and siliceous gangue while using sodium oleate as collector and sodium silicate as modifier. The pulp liquid is analysed for oleate, silicate, carbon dioxide, calcium, magnesium and phosphorous after each flotation test under different reagent conditions and flotation pH. Theoretical calculations of thermodynamic chemical equilibria in apatite-calcite-sodium oleate-sodium silicate system have been carried out with the help of SOLGASWATER computer program. During the calculations, the chemical variables are maintained similar to the operating chemical variables in flotation. A comparision between the experimental and theoretical chemical equilibria has been made and the flotation behaviour of apatite is discussed with reference to the theoretically calculated pulp model.

Jan 1, 1993