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By A. Thatcher, C. Day, C. Meyer

The purpose of this paper is to provide general information about the bioaccessibility of metals and specific information about the use of bioaccessibility in risk assessments (human health risk assessments [HHRA] or ecological risk assessments [ERA]) and a list of sites where regulatory agencies have approved the use of bioaccessibility data in risk assessment. The memorandum also cites current U.S. Environmental Protection Agency (USEPA) guidance as well as state specific guidance where applicable. BRIEF HISTORY OF METAL BIOACCESSIBILITY TESTING AND METHODS The bioaccessible fraction of a constituent is that fraction that dissolves or desorbs from its matrix (e.g., soil) in the gastrointestinal tract and is available for absorption (USEPA 2007a; ITRC 2011; ITRC 2017). This is different from the bioavailable fraction, which is the percentage of the amount of an element that an organism is exposed to that is absorbed by that organism during a given time under defined conditions (USEPA 2007a). The bioaccessibility factor is the percentage of a metal that is potentially available for absorption and, therefore, is a conservative estimate of the bioavailable fraction since all that is available for absorption may not ultimately be absorbed into the organism’s system. Currently, there are two main techniques for estimating bioavailability of metals within a medium: in vivo animal studies (time-consuming and often cost-prohibitive), and in vitro tests that simulate human, or animal digestion in a laboratory setting. In vitro and in vivo test methods and protocols have been extensively evaluated by numerous researchers (Ruby et al. 1996; Rodriguez and Basta 1999; Sips et al. 1998; Sips et al. 2001; Molly et al 1993; Oomen et al 2002; Kelley et al. 2002; Oomen et al. 2003; Furman et al. 2006; Drexler and Brattin 2007; Basta et al. 2007; Wragg et al. 2009; Wragg et al. 2011; Chaney et al. 2011; Bradham et al. 2015; Bradham et al. 2018). The most recent scientific literature demonstrates that protocols used to estimate the bioavailability of metals to mammals also predict bioavailability of metals to birds as well (Beyer et al., 2016).

Jan 1, 2019

By James F. Archibald

In historic mining practice, typical thin liner support systems have been considered to comprise non-reinforced or mesh-reinforced shocrete linings. In the early 1990?s, development of alternate forms of liner systems was initiated in Canada which is now undergoing significant international growth in countries which sustain major mining activity. Now internationally designated as thin, spray-on liner systems, a wide spectrum of liner materials, ranging from liquid/liquid to liquid/solid component combinations, has become commercially available. This innovative family of products is characteristically identified as being rapidly deployable, capable of creating ultra-fast setting coverage over rock surfaces, and able to develop tenacious adhesion and pull strength capacities for resisting rock falls and movements. This paper presents a summary of current liner developments and use in principal mining districts world wide. Additionally, a database of material properties for principal product types used in mining and a review of common quality control testing procedures under development are provided. Such information is based upon recent Canadian and international efforts being taken to assess and develop user standards for the implementation of thin, spray-on liners as rock support in mines. This work is intended to continue for a period of years, with the eventual goal being to establish support and installation guidelines for mines based on quantifiable laboratory and field research.

May 1, 2002

Improvement of Phosphate Ore Flotation Performance Through Sized Flotation

Sep 13, 2010

By W. P. Yant, R. R. Sayers, H. W. Shoaf, John Chornyak

"The contemplated use of dichloro-difluoro methane in domestic and commercial refrigerating appliances and in air-conditioning equipment for Public buildings and possibly homes, brings attention to the health hazards involved in a wide potential exposure of the public to vapors of another new product, and for the first time to vapors of an organic fluorine compound. The objective in the development of this new refrigerant, however, has been the mitigation of health and explosion hazards in automatic refrigeration, and accordingly these factors have been given primary attention. Early in the development, the Bureau of Mines was requested to make a laboratory study of the toxicity and potential hazard:"" and it was on the basis of the results of this work and the results of a preliminary investigation made in another laboratory5 that the compound has been selected for commercial use. Although the investigation conducted by the Bureau of Mines is still in progress, information has been obtained to indicate the order of the toxicity and the magnitude of the health hazards involved in the use of dichloro-difluoro methane as a refrigerant. The following is a summarized report of the work completed to date:Additionally work rich is in progress at the present time includes a determination of the lethal time-concentration curve for animals and a study of the response of persons within the range of safe concentrations.The writers desire to jive acknowledgment to T E. Midgley, Frigidaire Corporation, Layton, Ohio, for suggesting the investigation, for arranging for the cooperation of the Frigidaire Corporation, and for advice during the experimental work; to Robert A. Kehoe, The Eichberg Laboratory of Physiology, University of Cincinnati, Cincinnati, Ohio; and E. R. Hayhurst, college of Medicine, Ohio State University, for consultation and advice in planning the work; and to the following employees of the Bureau of Mines for assistance in performing the experimental work: L. M. Berger, chief scientific aid, S. J. Pearce, junior chemist, and Ethel B. Stead, technician."

May 1, 1930

By K. V. Konigsmann

"The results of Mr. Klymowsky's research confirm the essential role played by oxidation products in the flotation of base metal sulphides. They invite a discussion on the subject of aeration which I may open by a brief description of the development and current practice of aeration. The first installation of pre-flotation aeration in Canadian milling practice was undertaken during the years 1928 and 29 at the then new Noranda Mill. C.G. McLachlan and his collaborators demonstrated that the flotation differential between chalcopyrite and iron sulphides was enhanced by aeration in soda ash alkaline pulps. The ores treated contained more than 80 per cent sulphides. It was proposed already then that the products of mineral oxidation assisted copper and retarded iron sulphides, at least pyrrhotite flotation. The concentration of thiosulphates was used as a measure of the progress of oxidation. Several papers by C.G. McLachlan elaborate on this subject.The aerator was also used as classifier since it was held that aeration, i.e. controlled oxidation, should go hand in hand with creation of new mineral surfaces. Grinding mills and aerators were placed in closed circuit. Figure 1. This aeration was essential for successful separation at Noranda.Following the application of aeration at Noranda the technique was applied to existing mills in N.W. Quebec. Impressive improvements in concentrate grades and recoveries were obtained. It was observedthat the zinc flotation benefitted from aeration as much as the preceding copper float. In the late forties and fifties the aerator classifier was installed in new mills associated with the Noranda group. A diagrammatic sketch of the Quemont flow-sheet (figure 2) may serve as a typical example."

Jan 1, 1973

By I. R. Firth, D. L. Taylor

The ability to accurately model the movement of grade boundaries during a typical bench blast would be of significant benefit to mine operators. The movement of grade boundaries during the blasting process may have significant impact on grade recovery if not accounted for. The paper describes the preliminary stages of a research project which combines numerical blast models and conventional mine planning software to allow practical use of the results of a numerical blast simulation. A two dimensional bench blast is simulated using the Universal Distinct Element Code (UDEC). The results of the simulation are used to provide input to the Surpac mine planning package which can be used to generate grade control plans.

Jan 1, 2001

By C. B. Webber, W. A. Grell

"Sherritt Gordon's Ruttan Mine is a copper-zinc operation located approximately 600 miles north-west of Winnipeg. Open pit mining began in 1973 at 10,000 Tpd., with a change over to underground mining in 1981 producing 7,500 Tpd. Ore is crushed to -3/4"" followed by rod and ball mill grinding (two ball mills in series), differential copper-zinc flotation, and dewatering. The copper and zinc concentrates are trucked 75 miles to Lynn Lake, where they are shipped by rail to the HBM&S smelter at Flin Flon.This paper describes a method used to predict the effect of grind particle size on metallurgical performance, as well as details on the copper and zinc metallurgical performance due to fine grinding in actual plant operation.Initial statistical studies on historical data (including ore source, head gr3de, grind, etc.) indicated that copper and zinc recoveries increased with fineness of grind, in the range of 50 to 65% -200 mesh.In order to extrapolate beyond 65% -200 mesh, and to develop expected nonlinear relations between grind, Cu concentrate grade, and recovery, the assays of screen fractions of copper concentrate and tailing were used to determin8 the relation between net smelter return (a function of grade and recovery) and grinding cost. The optimum economic grind would be that grind at which the net smelter return less grinding cost reached a maximum."

Jan 1, 1982

By E. B. Nelson, B. W. Gandrud, B. M. Bird

"The Lewisburg No. 2 mine of the Sloss-Sheffield Steel & Iron Company is located in Jefferson County, Alabama, about 7 miles due north of Birmingham. At this point the coal from the Mary Lee seam when coked in by-product ovens yields an excellent quality of metallurgical coke suitable for use in the iron blast furnace; it is also an excellent steam coal. In mining, all three benches are worked. Coarse impurities are largely gobbed by the miners underground.In addition to giving the data obtained from screen-sizing and float-and-sink tests of a representative sample of the raw coal, this report presents the results of slotted-screen tests to show the proportions of flaky particles in selected sizes, and the results of tests to show how much coal is liberated from impurities by crushing the coarsest sizes. These data have been obtained in connection with an extensive study of coal-washing now being conducted by the U. S. Bureau of Mines and the University of Alabama, with U. cooperation of the different operators of Alabama. As the work progresses other reports will follow containing furtner data on the washability both of the Mary Lee seam and of other seams in Alabama and giving the results obtained in preparing these coals by various methods.Although a great amount of investigative work on the preparation of the Mary Lee scam was previously carried on by the various coal companies of the district, comparatively little of this information has been published. In governmental publications three references have been found. Forbes5 gives a number of sections with proximate and ultimate analyses of face samples taken in the mines. Gandrud and Britton'' show sections of this seam at Flat Creek and New Castle; they also give the specific gravity and ash contents of the partings of coal and impurities. In their paper Yancey and Fraser7 include washability studies and washing data from the Sayreton mine of the Republic Iron & Steel Co."

Jun 1, 1930

By C. E. Brechtel

This project describes the design and testing of large face ventilation systems for oil shale mining. A design data base was generated by reviewing general industry practice, oil shale industry planning, and technical literature. Conceptual designs for seven different systems were developed and evaluated for suitability. A large, free-standing, jet fan and reversible fan with rigid duct were selected for fabrication and testing. The two systems were field tested in a dead-end heading 55 ft wide by 30 ft high and 320 ft long. System performance was optimized using measurements of air flow direction and air velocity. Total system performance was then measured using SF6 tracer gas released to simulate blast fumes, hot diesel exhaust, methane layering and methane from a blasted muckpile. Field testing indicated that both systems delivered similar performance. The jet fan offered some clear advantages because of its mobility, ease of oper-ation and lower power requirement. It also offered some functional advantages in ventilating for methane because of it high average velocity.

Jan 1, 1985

By M. J. Gregory

The Pebble Cu-Au-Mo deposit in southwest Alaska is one of the world's largest porphyry deposits. The western part of the deposit was discovered by Cominco America in 1987, who sold the project to Northern Dynasty Minerals Ltd., in 2001. Northern Dynasty discovered the high-grade eastern part of the deposit in 2004 and went into a 50:50 partnership with Anglo American PLC in 2007, forming the Pebble Limited Partnership (Lang et al., 2008). The Pebble Limited Partnership has continued to delineate the deposit through diamond drilling with the most recent resource estimate released in February 2010 (Pebble Limited Partnership, 2010). The Pebble deposit mineral resources comprise 5.94 billion tonnes of measured and indicated resources grading 0.78% Cu EQ, containing 55 billion pounds of copper, 67 million ounces of gold and 3.3 billion pounds of molybdenum. Also delineated are 4.84 billion tonnes of inferred mineral resources grading 0.53% Cu EQ, containing 25.6 billion pounds of copper, 40.4 million ounces of gold and 2.3 billion pounds of molybdenum (Pebble Limited Partnership, 2010). Resources are calculated using a 0.3% Cu EQ cutoff. GEOLOGY AND MINERALIZATION Deposit Geology The Pebble deposit is located in the Kahiltna terrane, between terminal strands of the north-east-striking Lake Clarke strike-slip fault. This fault represents an accretionary boundary and separates the Kahiltna terrane to the north-west from the Peninsular terrane to the south-east (Lang et al., 2008). The Pebble deposit represents a large magmatic-hydrothermal system centered on a group of 90 million year old porphyritic hornblende granodiorite intrusions. An east-west cross section through the southern part of the deposit (Figure 1A) shows the typical relationships between the various rock units which host sulfide mineralization. Sub-parallel ~96 million year old granodiorite and diorite sills were intruded into siltstones of the Jura-Cretaceous Kahiltna flysch. In the west, these sills were cut by a ~96 million year old alkalic intrusive complex composed of porphyritic monzonites and monzodiorites and related intrusion breccias (Bouley et al, 1995). The mineralized 90 million year old hornblende granodiorite intrusions cut all rock types and comprise four small stocks in the western part of the deposit and a larger pluton in the eastern part of the deposit. Recent deep drilling indicates that these intrusions coalesce at depth. The strongest porphyry-style mineralization is centered on the eastern granodiorite pluton and extends into the surrounding rock units (Figure 1A). The western half of the deposit crops out at surface, whereas the eastern side is un-conformably overlain by a cover sequence of Late Cretaceous to Eocene sedimentary and volcanic strata. The deposit was tilted 20º to the east during the Eocene.

Jan 1, 2012

By Edward D. Graf

Once the heavy work of mining, supporting and completing an underground structure is finished, there is frequently the problem of handling unwanted water infiltration into the opening. Methods of controlling the infiltration vary from collecting and channelling the inflow to shutting off the water at the surface of the opening or within the ground formation. Discussed are various methods of controlling ground water inflow from within the structure including collector pipe systems, shotcrete, cement grout, bentonite, and various chemical grouts. Case histories illustrating some of the methods and materials will be presented.

Jan 1, 1987

By S. Chander, S. W. Musselman

The molecular structure of hydrophobic and hydrophilic groups in nonionic surfactants has been related to the wetting and dispersion of selected pigments. The nonionic surfactants included in this study are acetylenic diol based surfactants and ethoxylated alkyl phenols. The Langmuir model could be used to fit adsorption data. Further analysis of the data showed that the free energy of adsorption was a function of adsorption density of the surfactants at the interface. The change in free energy with adsorption density could be interpreted by considering a change in the orientation of the adsorbed molecules. Acetylenic diol based surfatants were found to have an area per molecule of 2-3 times that of similarly ethoxylated alkyl phenols. The wetting and dispersion properties of lamp black, a model hydrophobic surface, by these surfactants were investigated by contact angle measurements and particle size analysis. Acetylenic diol based surfactants with ethylene oxide contents between3.5 and 10 moles per molecule and alkyl phenol based surfactants with approximately 9 moles of ethylene oxide per molecule were found to provide superior wetting abilities. Longer ethylene oxide chains were required for superior dispersion capabilities within each family of surfactants. Complete wetting and dispersion was found to occur above the critical micelle concentration of the surfactants.

Jan 1, 2000

By M Ash, P Bellairs

The world class iron ore mines at Mt Whaleback, Tom Price and Paraburdoo located in the Hamersley Province of Western Australia must mine the Mt McRae Shale to obtain high grade ore from the Dales Gorge Member of the Brockman Iron Formation. The Mt McRae Shale contains a Black Pyritic Shale lithology that reacts with Ammonium Nitrate based explosives. This paper provides an overview of the problems associated with mining this reactive rock type as well as the development of a comprehensive procedure to safely and efficiently blast, excavate and dispose of this material.

Jan 1, 1995

As the high-grade copper deposits in the world become depleted, there is an increasing focus on developing lower-grade ores which contain problematic impurities such as arsenic. Indeed, many high-arsenic ore bodies remain undeveloped because of their high arsenic levels. Separation of arsenic from copper at the beneficiation stage is difficult using the current processing techniques and invariably copper concentrates produced from these ores contain high arsenic levels, sometimes so high as to make them unacceptable to copper smelters. New, sustainable approaches are needed to allow development of high-arsenic copper ores while at the same time minimizing arsenic dispersion into the biosphere. The most promising route for separating arsenic from copper at the flotation stage centers on the use of pulp potential control. In recent years CSIRO has demonstrated at laboratory scale, for a number of high-arsenic copper ores, that crude flotation separation between arsenic-bearing minerals and copper-bearing minerals can be made. The differences in specific minerals responses to changes in pulp potential and pulp pH are exploited for this separation. Such separations nominally produce a low-arsenic high-copper concentrate and a low-copper high-arsenic concentrate. The former can be smelted without penalty, while the latter requires further treatment to capture and stabilize the arsenic and to recover the residual copper. Consideration has now been given to treatment options for the high-arsenic low-copper product. A pyrometallurgical option, involving a low temperature roast to selectively fume off the arsenic and leave a high-copper calcine, coupled with an arsenic stabilization step, has been demonstrated in the laboratory, and a preliminary techno-economic evaluation shows the process to be economically favorable. These results were recently published. CSIRO has now investigated an alternate hydrometallurgical option, involving atmospheric alkaline sulphide leaching of the high-arsenic product, where the arsenic is selectively dissolved leaving a copper-rich leach residue. The leaching testwork was carried at on the same high-arsenic low-copper material used in the roasting studies, enabling a techno-economic comparison of the alternate roasting and leaching treatment options to be made. The alkaline leaching work is briefly described and the results of the process option comparison presented and discussed. Keywords: arsenic, copper, economics, enargite, ore flotation, tennantite INTRODUCTION

Sep 1, 2012

By J. K. Weglo, M. U. Savich

"The measurement and evaluation of the noise emanating from an ST4A scooptram in an underground stope under a simulated work cycle, and under three conditions of after-treatment systems is covered.These include scooptram without muffler or filler (bare engine), an in-line small filter, compared to a larger-filter, and the larger filter with an in-line muffler in series with fume diluter, which were tested under three engine operating conditions-IDLE, wide open throttle (W. 0. T.), and working condition. This is load, short haul and dump operation.The results showed an attenuation of the scooptram at work of 8 to 15 dBA, 16 cm from the exhaust pipe of the machine, to 4.8 dBA at the operator's ear. Recommendations are made to increase the attenuation at the operator 's ear by additional improvement in design of the fume diluter.IntroductionIn current mining operations, the diesel engine provides a safe, efficient and highly mobile source of power. In the major underground mine s in Canada the most common types of diesel equipment are load-haul-dump (LHD) machines and ore trucks. In general, there is a tendency to use high horsepower, diesel LHD machines in mines to achieve maximum productivity. The increased use of diesel-powered equipment in underground mines has shown no cause pressure levels were measured at the exhaust and outlet pipe. Also, while measuring the octave band and A-weighted sound pressure levels, the operator's position was also measured."

Jan 1, 1986

By I. S. Parrish

One of the most common errors uncovered while performing a reserve, or resource, audit is not in the geological modeling or grade problems due to poor sampling, prepartion or assaying. The error most commonly found is in tonnage or, more specifically, in the tonnage factor - that factor applied to volume to derive tonnage. Tonnage factors In the metric system, the tonnage factor is the density, or specific gravity. Specific gravity (Sp.g.) is defined by Dana (1947): • "The specific gravity of a mineral is the ratio of its density to that of water at 4° C (39.2° F). • "Density is the mass of the unit volume or weight of the body divided by the weight of an equal volume of water." When Sp.g. is multiplied by the metric volume it yields metric tonnes. In the English system, the tonnage factor is usually expressed in cubic feet per short ton (cu ft/st). When the volume in cubic feet is divided by cu ft/st, the resulting figure is in English short tons. Table 1 gives the cu ft/st factors equivalent to specific gravities from 1.6 Sp.g. to 5.8 Sp.g. The table is based on the following equation: cu ft/st = 0.9072 divided by Sp.g. times 0.02832 The blase attitude that most geologists have toward tonnage factors is echoed in the prevailing definitions of Reserves and Ore, as provided by the US Securities and Exchange Commission (S.C Form S-18), Canadian National Policy 2A and the SME Proposal for Reporting Terminology (SME February 1991). In each case, it is stated that "quantity" (SEC, SME), or "tonnage" (Can.2A), "is computed from dimensions revealed in...." etc. Unfortunately, "dimensions" do not directly yield tonnage. Dimensions must be factored by density to derive tonnage.

Jan 1, 1993

By F. G. Miller, H. C. Miller

Petroleum technologists and progressive operators constantly are striving to increase the percentage of oil that may to recovered from reservoir rocks through wells. The exhaustive studies that have been made of the function of natural as in the production of oil, for example, have aided operators greatly in increasing the quantity of oil recovered from reservoirs. Natural gas dissolved in and otherwise associated under pressure with oil in reservoir rocks, however, is not the only source of energy available for moving oil through sands to wells. In becoming "reservoir—energy conscious" engineers have learned that in many petroleum reservoirs the edgewater flanking the oil accumulation constitutes a potential source of energy capable, through proper control, of increasing oil—recovery efficiencies materially. No longer is the encroachment of water into the oil— and gas—filled tart of the reservoir considered as an evil to be combatted by devious methods but rather a natural consequence, incident to the withdrawal of nil and as from the wells, that may be used advantageously in lengthening the flowing life of wells and increasing the economic recovery of oil and gas.

Mar 1, 1938

By Laurel E. Blackman

The DFI Project Information Management Systems (PIMS) Committee cooperated with the US Army Corps of Engineers (USACE) to develop a specification for PIMS used on USACE projects. Once completed the Committee developed a more generic version of this specification for general use, which is contained in this document. This first edition has simply removed the USACE-related requirements from the document. The committee will continue to work on this specification to enhance the content and also incorporate recent technological development for these systems. It is the Committee's intention that a second edition will be issued in 2022.

Jan 1, 2021

By R. Bokotko, J. D. Miller, J. Hupka

Laboratory results from an initial study on the removal of SO2 from gas mixtures are reported using air-sparged hydrocyclone (ASH) technology. Tap water and alkaline solutions were used for absorption and the influence of gas flow rate, water flow rate and length of the ASH unit were investigated. Complete removal of SO2 was possible with very favorable kinetics. The efficiency of sulfur dioxide absorption from air using the ASH is compared with the efficiency of conventional technology.

Jan 1, 2002

By H. Cevizci

"Numerical simulation of the plaster stemming method (PSM) was performed and compared with the conventional drill cuttings stemming method (DCSM). Many earlier in situ tests have proved that PSM can use the blast energy more efficiently than DCSM. Despite PSM generating more blast vibrations, it has advantages over DCSM such as better fragmentation and lower cost per unit volume of rock blasted. In this study, numerical simulation with Autodyn software using a 2D tool was employed to prove the efficiency of plaster stemming by comparing parameters such as pressure, Y-velocity, Y-force, internal energy, acceleration-Y, and compression. For example, the maximum pressure attained at the top of explosive column was 7 395 MPa for DCSM whereas it was as high as 11 945 MPa for PSM. Most of the computed parameters were significantly higher in PSM than those obtained for DCSM. This paper is the first study elucidating the efficiency of PSM by numerical simulation. It is concluded that PSM can save substantial amounts of money and effort. IntroductionThe stemming of blast-hole collars in surface mines with an inert material redirects blasting energy to the rock more efficiently, thus the blast-induced energy is utilized more effectively in breaking rock. With proper stemming, the gases should not escape due to loose stemming material. More efficient stemming with better confinement therefore increases the blast fragmentation. In addition, the distance of scatter is increased, giving rise to a looser rock pile that can be more easily loaded and transported. In order to improve the performance of a blast, stemming is used to help maintain the gas pressure over time (Konya and Konya, 2018). Proper stemming has been shown to increase the explosive efficiency by over 41% (Snelling and Hall, 1912).The most common stemming material in open pits and quarries is drill cuttings because of their ready availability at blast sites and the drill cuttings stemming method (DCSM) is a low-cost method. However, it has a major disadvantage in that dry drill cuttings eject very easily from blast-holes during an explosion, thus a great percentage of the blast energy is wasted and lost to the atmosphere. Cevizci (2012, 2014, 2013, 2017) studied blasting parameters in open pits and obtained better results with the plaster stemming method (PSM) in many limestone, basalt, and clay quarries. Moulding plaster is preferred for stemming because of the fast hardening time of 25–30 minutes."

May 1, 2019