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By E. Spencer

Overexposure to hazardous noise has been found in most mining sectors, with up to 100% of the surveyed workforce experiencing a noise dose over the Mine Safety and Health Administration (MSHA) permissible exposure level (PEL). As a result, miners show elevated rates of hearing impairment of 70-90% by retirement age. To help manage noise exposures, the National Institute for Occupational Safety and Health (NIOSH) developed the Determination of Sound Exposures (DOSES) software and implementation guide for use by mine management and safety personnel. The software relies on a time-motion study that profiles the worker?s daily activities. Observations about the worker?s location and tasks or other activities are recorded along with the start and end time, to determine the duration of the tasks, so they can later be matched up with the noise data. The software gives the user the option of assessing dose relative to the MSHA PEL, the Action Level or the NIOSH Recommended Exposure Limit. The software generates a variety of interactive onscreen displays showing where, when, and how the worker?s noise dose accumulated. It also can generate customizable printed reports. These outputs can be used to highlight the tasks, locations, and times that are associated with the greatest amount of the worker?s noise exposure. DOSES simplifies the record keeping and analysis associated with time-motion studies and worker noise exposures, so mine management can make engineering noise control or administrative control decisions to limit the noise over-exposure of their workers.

Jan 1, 2010

By C. Grisanti, E. Prina Howald

The major of Swiss territory is occupied by mountains. Natural events as floods, debris flows, landslides, rockfalls, and avalanches regularly threaten the safety of people and properties. On the one hand, extreme weather events cause great damages, on the other hand, the enhancement of territory’s exploitation increases the risk. The Swiss Government makes many efforts to deal with the prevention of natural hazards, especially through measures of land management. As stated by federal law, Swiss cantons are obliged to establish hazard maps and to take the risk into account in the land management. Hazard maps are based on the hazard matrix, whose abscissa and ordinate are probability and intensity of the event on site. This project focuses on rockfalls. It consists of three main parts: the creation of a database to collect data on site, the creation of a catalog with all type of measures, and the development of a methodology for the analysis of the effectiveness of protective measures. The creation of the database allows us to collect information: about the site, about protective structures implemented on it, and about failures. With many multiple choice fields and few free text fields, it can collect data in a homogeneous way, without redundancy. The catalog has to be a tool that gives a basis to make decisions. It collects information about all types of protective measures implemented on Canton Vaud’s territory or available on the Swiss market. Free text fields allow for data storage of specifics, to give a complete view of structure’s characteristics and potentials. Methodology consists of four steps. The core of the procedure is the structure’s evaluation following a score system; it allows for calculation of reduction factors that have to be applied to intensity and probability parameters of the structure. Then it is necessary to convert the reduced structure’s intensity value into a residual site’s intensity value. Although the first step enables us to choose suitable measure for a specific site, it is not necessary to perform it. Second step allows us to evaluate structures under scenario 0, where structures are in best conditions. Third step allows us to evaluate structures under six scenarios of possible failings. Fourth step allows us to convert structure’s reduced intensity into event’s residual intensity and to establish the new point on hazard matrix. While the procedure has already been defined, details of score system and conversion have to be developed during the second phase of the project.

Jan 1, 2015

By Gwendolyn D. Hood

The U.S. Bureau of Mines developed a dewatering technique for treating wastewater that was tested on waste slurry from a commercial tile company in Alabama. Raw wastewater samples were pretreated with 10 Ib calcium chloride and 10 lb Wyoming bentonite per 1,000 gal of slurry. After pretreatment, polyethylene oxide (PEO) at dosages varying from 0.05 to 0.20 lb per 1,000 gal was mixed with the waste slurry, forming strong, tough floes that were separated from the clarified water using a trammel. The flocculated slurry was dewatered to a consistency that could be handled for subsequent disposal in a landfill. The clarified water quality was equivalent to that of the company's present treatment system.

Jan 1, 2010

By Geo. D. Furse

"The information that has accumulated regarding the geology of the McIntyre mine is the result of work by several geologists and, as might be anticipated, their conclusions have varied. The writer has been at the mine only a few years and due to wartime conditions has not been able to study and review the mine's geology as thoroughly as his predecessors. Where the writer's conclusions differ from those of previous authors, it should be noted that he has been unable to re-map all the workings in which flow contacts are exposed, but has endeavoured to describe the structure as indicated by the evidence he has been able to observe. He wishes to thank H. G. Skavlem and H. S. Robinson for their constructive criticism of this paper, and McIntyre Porcupine Mines, Limited, for permission to present it. A list of references is appended.The McIntyre mine is in the central part of the Pearl Lake section of the Porcupine gold area. It includes the ""bed of Pearl lake, twenty-two claims to the north of the lake, and the Platt Vet lot to the southeast. It is bordered on the west by the Hollinger and on the east by the Coniaurum property. The chief ore-bearing veins on the upper levels lie very close to the north shore of the lake, but some occur under the lake, and others of lesser importance are found to the southeast. The most important veins are Nos. 3, 5, 7, 10, and 25. Some of the veins extend into the Hollinger. on the west and others cross the east boundary into the Coniaurum. The total production since the commencement of milling in 1912 to the end of March 1947 has been $168,448,218 in gold and silver from the milling of 17,690,963 tons of ore."

Jan 1, 1954

By M. L. Free, N. Dhawan, M. S. Safarzadeh, J. D. Miller, M. S. Moats

"The drum agglomeration of nickel laterite and gold ores has been optimized through the design of experiments (DOE) using a Taguchi L16 (45) orthogonal array to determine the optimum conditions for maximizing average agglomerate size and minimizing the amount of fines. The effects of controllable operating factors including moisture content (nickel laterite ore: 34-37%; gold ore: 7-10%), retention time (2-3.5 min), drum speed (15-45% critical speed), drum load (nickel laterite ore: 8-32 %; gold ore: 6-22%) and acid concentration (150-600 g/L) on the performance of the agglomeration process were studied.For nickel laterite ore, maximum average agglomerate size and minimum percent fines (-1 mm) occurred under the following conditions: drum load (23.7%), moisture (36.5%), time (3 min), drum speed (30% critical speed) and acid concentration (150 g/L). Under the studied nickel laterite ore conditions, the most effective parameters for maximizing average agglomerate size and minimizing the amount of fines were found to be drum load and acid concentration, respectively. Drum speed had a statistically significant effect on minimizing the amount of fines. Maximum average agglomerate size and minimum percent fines (-1 mm) for gold ore occurred under the following conditions: drum load (19.3%), moisture (8.5%), time (2 min 15 s) and drum speed (40% critical). The most significant factors for maximizing average agglomerate size and minimizing the amount of fines for gold ore were found to be drum load, time and moisture.IntroductionSeveral heap leach operations have experienced problems in terms of poor recovery due to percolation issues caused by low-grade complex ores, tailings and clayey deposits. Poor percolation can lead to low metal extraction due to solution channeling or the development of impermeable/dead zones within the heap (Dhawan et al., 2012; Kappes, 2005). Improper heap building practices such as the use of loose agglomerates and inadequate attention toward the presence of clay minerals have been among the main reasons for percolation issues. During the transport of ore material, severe segregation of the material can occur. To overcome percolation problems, a major improvement was made through the introduction of agglomeration prior to ore placement. If the ore particles and agglomerates are of similar size, segregation can be avoided to a great extent (Dhawan et al., 2013; Kinard and Schweizer, 1987; McClelland and van Zyl, 1988). Agglomeration improves the uniform percolation of solution through ore heaps and is applicable to many ores, wastes and milled tailings (Bouffard, 2005; Dhawan et al., 2013). Manning and Kappes (2005) reported agglomeration/ stacking accounts for ~14% of the total heap leaching operating cost. The cost of binder is a primary contributor toward the total cost. Also, the lack of consistent quality control tests for agglomerate often leads to operational problems. The details are mentioned elsewhere (Dhawan et al., 2013). Considering the significant contribution of the agglomeration/stacking step toward the total heap leach operating cost, it is appropriate to study the agglomeration behavior and its optimization for two different ores. The reason to study the same parameters for different ores is the fact that significant variability in the agglomeration behavior of different ores has been reported to exist in industrial operations."

Jan 1, 2015

By D Tuazon, M Powell, M Ziemski, G D. Corder

Although mining companies have made broad corporate-level commitments to adopt sustainability, there continue to be problems when attempts are made to adopt higher-level sustainability aspirations and translate them into appropriate targets and methods at the more-specific operational level. The integration of sustainability principles into minerals processing operational decision-making processes has unique challenges that are not addressed adequately by current tools and methodologies, yet impacts from operational decisions can have longer-term effects realised at closure and rehabilitation.This paper describes a proposed methodology to achieve the integration of sustainability at the operational level through a systematic and rigorous process of identifying and qualifying sustainability issues and opportunities in an operation. The methodology, starting from a sustainability point of view rather than an operational one, guides the identification of process issues and opportunities by examining the operation, unit-by-unit, similar to a Hazard and Operability (HAZOP) process. Each issue or opportunity is qualified according to its measurability, scopes of impact and consequences so that it may be understood fully and the correct engineering problems are formed. Through improved decision-making to account for broader sustainability factors, operations can better address environmental and social expectations and pressures (both corporate and community, as well as immediate and in the longer-term), whilst still delivering on operational and business goals.The methodology has been tested with two case studies at minerals processing operations. At one site, the methodology identified a dust issue which had considerable business risks (loss of valuable product) compared to conventional engineering analysis processes. The other site also benefited from using the methodology as an opportunity to improve the operation of the milling and flotation circuits was identified. The opportunity not only showed a potential to improve operational efficiency, but also potential improvements in water and energy efficiency and a resulting increased resilience against water and energy supply risks. It was important to utilise the holistic approach of the methodology in the identification of opportunities at this site; the goals of the operation showed a strong coupling between water and energy issues which would be difficult to overcome using the operationÆs current organisational model, which deals with such issues separately of each other.CITATION:Tuazon, D, Corder, G D, Powell, M and Ziemski, M, 2012. A practical and rigorous approach for integrating sustainability principles into decision-making processes at minerals processing operations, in Proceedings Life-of-Mine 2012 , pp 233-242 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By Phillip R. Moyle

In 1985 the U.S. Bureau of Mines evaluated the mineral resources of tie Bruneau River and Jarbidge River study areas, Owyhee County, ID, for the U.S. Bureau of Land Management. The study areas, separated by a narrow corridor, include 90,000 acres of the 107,020-acre Bruneau River Wilderness Study Area (ID-111-17) and 47,000 acres of the 75,340-acre Jarbidge River Wilderness Study Area (ID-17-11). They lie 26 miles and 55 miles, respectively, due south of Mountain Home, ID. Approximately 38 placer claims for gold and 182 lode and placer claims for jasper, agate, and limestone were located within and adjacent to the study areas from 1893 to 1981. Currently, there are eight mining claims for jasper at Indian Hot Springs along the corridor between the study areas.

Jan 1, 1987

By A. J. Baer

"DEFINITION OF THE REGION AND ITS BOUNDARIESTHE EXPOSED PART OF THE GRENVILLE PROVINCE is the southeastern part of the Canadian Shield, characterized by crystalline rocks with K-Ar ages of about 1,000 million years. Its Canadian portion is bounded on the southwest by Georgian Bay •and by Paleozoic sediments south of a line passing through Orillia and Kingston, on the southeast by the St. Lawrence River valley and the north shore of the Gulf of the St. Lawrence, on the east by the coast of Labrador and on the northwest by the Grenville front, a linear tec-tonic feature that is a metamorphic transition zone and/or a fault. Rocks located to the southeast of the front have younger K-Ar radiom€tric ages than rocks located to the northwest of it.The region is formed of complexly deformed and highly metamorphosed crystalline rocks and in part differs from other areas of the Canadian Shield by the presence of large amounts of crystalline limestone and bodies of anorthosite."

Jan 1, 1970

By S. K. Pan, R. Venugopal, L. A. Kumaraswamidhas, Rakesh Prasad, Chandan Pandey

Cold compressive strength (CCS) and apparent porosity (AP) of pellets are essential properties regarding the burden of blast furnaces. The optimal required values for industries are 2.5 KN CCS and 21% AP. Blaine fineness and firing temperature are the decisive parameters analyzed here. During firing, microstructure phases such as silicate, hematite, and pore are formed. The phase’s grain density during induration influences the pellet’s CCS and AP. The influence of the factors over the response is evaluated by I-optimal (response surface methodology) design. Blaine fineness, firing temperature, pore phase grain density (PPGD), silicate phase grain density (SPGD), and hematite phase grain density (HPGD) affect the CCS and AP of pellets. The RSM-I-optimal predicted responses with a coefficient of determination (R2) of 0.89 for CCS and 0.91 for AP of iron ore pellets. Optimal conditions were Blaine no. = 1668 cm2/g, 1250 °C firing temperature, PPGD value 90 no/mm2, SPGD value 250 no/ mm2, and HPGD value 490 no/mm2, with 4.5 KN CCS 27%. The induration processes were investigated through statistical design of experiments for process optimization. Statistical analysis indicated the direct and interactive influence over CCS and AP. In this study, RSM-I-optimal modeling is used for iron ore pellets processing. The I-optimal prediction could be applied to make the process economical because information is obtained through fewer experiments.

Aug 18, 2020

By Mäkinen, Eero

OUTOKUMPU, a large copper mine in eastern Finland, has the distinction of being one of the few important mines in the world discovered by a geologist the late Otto Triistedt, of the Geological Sur- vey of Finland, having found the out- clop in 1910 by tracing glacial ore boulders, some of which had been carried as far as fifty kilometres. As the mine had no connection with either railways or waterways and the possibilities of transport were poor, the owners first tried the Hybinette hydrometallurgical process to extract the copper. The raw ore was finely crushed, treated by a sulphatizing roast. and then leached. The resulting solution was electrolyzed, using lead anodes. This experimental plant, having a capacity of 10,000 tons (all Ions are metric tons in this paper) of raw ore and producing 300 to LEO0 tons of electrolytic copper annually, was built in 1913 and run until dis-

Jan 1, 1938

By J. F. Brune

This is a shortened version of the paper ?The Methane-Air Explosion Hazard Within Coal Mine Gobs published in the 2013 volume of SME Transactions (Brune, 2013). This paper analyzes the explosion hazard resulting from the formation of methane-air mixtures in the mined-out gobs of underground longwall coal mines. Evidence from numerous mine explosions suggests that explosive methane zones can form within longwall gobs. Explosions and fires resulting from these methane accumulations have led to severe and fatal injuries to the miners, including the explosion of the Upper Big Branch mine in West Virginia, where 29 miners lost their lives. The paper also reviews current research on numerical modeling of gas flows in longwall gobs and outlines how targeted injection of nitrogen into gobs can effectively reduce the volume of such explosive methane zones. The paper concludes that comprehensive monitoring of gas compositions along the accessible fringes of the gobs along with inertization, improved ventilation schemes and further research are necessary to control this explosion hazard and make mining operations safe.

Feb 23, 2014

By Jürgen Brune

This is a shortened version of the paper ?The Methane-Air Explosion Hazard Within Coal Mine Gobs published in the 2013 volume of SME Transactions (Brune, 2013, pp. 376-390). This paper analyzes the explosion hazard resulting from the formation of methane-air mixtures in the mined-out gobs of underground longwall coal mines. Evidence from numerous mine explosions suggests that explosive methane zones can form within longwall gobs. Explosions and fires resulting from these methane accumulations have led to severe and fatal injuries to the miners, including the explosion of the Upper Big Branch Mine in West Virginia, where 29 miners lost their lives April 5, 2010.The paper also reviews current research on numerical modeling of gas flows in longwall gobs and outlines how targeted injection of nitrogen into gobs can effectively reduce the volume of such explosive methane zones. The paper concludes that comprehensive monitoring of gas compositions, along the accessible fringes of the gobs along with inertization, improved ventilation schemes and further research are necessary to control this explosion hazard and make mining operations safe. Keywords: Longwall, gob, methane, EGZ, explosive gas zones, underground, coal, explosion, fire

Feb 1, 2014

By S Viviers, G Ratner

Ventilation is part of all underground mine operations and is undertaken in order to introduce fresh, cool air to the workings and to remove stale, affected air. It is problematic to obtain efficient and accurate estimates of volume flow and static pressure in the installed operational configuration for the auxiliary axial flow fans.An empirical method was developed to estimate the static pressure and volume flow through a calibrated differential pressure port on axial flow fans. Prior to shipping, each fan is performance tested according to BS 848 (ISO 5801) to establish the fan performance curves. In addition to the standard required parameters captured to fully describe the performance, the differential pressure is measured across the fan rotor to enable correlation with the characteristic fan curve.The method was implemented on a ruggedised tablet PC platform. This compact platform is then used to calculate the volume flow rate from the differential pressure sensor measurement input via a USB port. The result is a real-time measurement of volume flow and operating point of the fan system. This can be used effectively in overall modelling of the mine auxiliary ventilation systems and calculation of system resistance could provide a health indication of the fan and duct system.CITATION:Ratner, G and Viviers, S, 2013. Underground auxiliary ventilation monitoring and diagnostic system, in Proceedings The Australian Mine Ventilation Conference , pp 57-62 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By Giuseppe Bonifazi

Minerographic and petrochemical research was carried out on crude ore samples from the complex polymetallic Zn-Cu-Pb sulfide ores of , Sotiel in Huelva province west of Seville, Spain. A computerized image analysis system was used to define the structural and textural characteristics of the ore to obtain information on the degree of liberation of the different minerals (i.e. pyrite, sphalerite, galena, chalcopyrite). Techniques of digital multispectral image processing of reflected light microscopy images were used. Particular structures were identified by means of mineral associations and numerically quantified to obtain useful information for designing beneficiation processes.

Jan 1, 1991

By William K. Tolley

The U.S. Bureau of Mines (USBM) is investigating hydrometallurgical processing techniques to recycle metals from semiconductors and other advanced materials. Cadmium and tellurium were recovered from mixed CdTe/CdS scrap produced in the manufacture of thin-film photovoltaic devices. Selective cadmium dissolution was achieved using oxygen-pressure leaching in dilute sulfuric acid. Leaching the scrap for 90 min at 110° C in 2.2NH2S04 under 400 psig 02 yielded 97% Cd extraction; however, cadmium content of the residue ranged between 4% and 7%. Soluble iron was added to the lixiviant to catalyze oxidation of the CdS component. Tellurium and sulfur remained in the leach residue primarily in the elemental form. The iron and tellurium were removed from the cadmium-rich leach liquor by adjusting the pH to 5.3. The cadmium was recovered as cadmium sulfate crystals by evaporating the solution. Alternative leaching and purification schemes are discussed.

Jan 1, 2010

By R. E. Whitehead, G. J. Prior

"Abstract -Biotite from aplite that appears to have crystallized simultaneously with disseminated Cu-Mo mineralization at MacLeod Lake in northern Quebec yields K-Ar dates in the range 2032 ± 44 Ma to '2f1:)1 ± 47 Ma. The mean value, 2065 Ma, is some 400 Ma younger than the 2485 ± 64 Ma date obtained from a hornblende concentrate separated from a granodiorite sill that is spatially, but apparently not genetically, associated with the disseminated Cu-Mo deposit. The mean biotite date of 2065 Ma at MacLeod Lake, a K-Ar date of 2055 Ma reported from an area 50 km east of MacLeod Lake and published dates of about 2000 Ma for galenas from the Chibougamau Cu-Au ores, suggest a widespread thermal and mineralization event, in that part of the Superior Province east of James Bay, that differs from the common late Archean mineralization that is related to volcanism and metamorphic-intrusive activity.Sommaire - Les datations au K-Ar sur des biotites qui auraient cristallisé en même temps que la minéralisation disséminée en Cu et Mo dans une aplite mise en place au Lac MacLeod, au nord du Québec, s'échalonnent entre 2032 ± 44 Ma et '2f1:)1 ± 47 Ma. La datation moyenne, soit 2065 Ma, est d'environ 400 Ma plus récente que la datation obtenue pour un concentré de hornblende extrait d'un fùon-couche de granodiorite qui est spatialement mais ne serait pas génétiquement as­ sociée à la minéralisation disséminée en Cu et Mo. La datation moyenne de la minéralisation au Lac MacLeod, soit 2065 Ma, la dataion au K-Ar à 2055 Ma citée pour une région à 50 km à l'est du Lac MacLeod, de même que les datations d'environ 2000 Ma établies pour des galènes qui se trouvent dans le minerai aurifère et cuprifère à Chibougamau, suggèrent un phénomène thermique répandu qui aurait produit la minéralisation dans cette région à l'est de la Baie James, dans la province du lac Supérieur. Ce phénomene serait différent de celui qui aurait produit la minéralisation répan­ due d'âge archéen tardif qui elle serait associée à l'activité volcanique et à l'activité intrusive accompagnée de métamorphisme."

Jan 1, 1992

By J. H. Howard

The purposes of this report are to summarize the findings of the Committee on the Challenges of Modern Society Non-electrical Project (a working committee of the North Atlantic Treaty Organization) and also, thereby, to provide an introduction and review of the current situation regarding non-electrical applications to those who are interested in the subject.

Jan 1, 1975

By M. Hitch, M. B. Lytle

Resource development conflicts arise largely due to differences in worldview between those who support and those who oppose development. This paper illustrates how societies and civilizations with different worldviews produce different levels of creative and economic energy. A questionnaire was created to build a database of responses to test whether worldview and resource development are correlated. Factor and multivariate regression analysis determined correlations for respondent groupings. Results showed a positive correlation between the respondents\u2019 worldviews and their attitudes toward resource development. Correlations became stronger as the homogeneity of the sample subgroups increased.

Jan 1, 2017

By H. B. Charmbury

The acid mine drainage problem in Pennsylvania is of continuing and growing interest to the coal mining industry, the state government and the citizenry at large. Approximately one-third of the total volume of mine drainage presently polluting the streams of the Commonwealth originates from active coal operations and two-thirds come from ?abandoned mine discharges.? For this reason the Pennsylvania Department of Mines and Mineral Industries has mounted a significant research and action program seeking solutions to this two-fold problem. The Coal Research Board of the Department has sponsored a wide variety of research projects in an effort to study the treatment of acidic and highly ferruginous mine waters. A review of the published literature on the treatment of mine waters indicated that many laboratory and theoretical studies had been undertaken on various aspects of the coal mine drainage problem, but little applied, developmental, or engineering study had been undertaken. In January of 1964 the Board commenced a rigorous program using state and industry funds in an effort to find a ?least cost? solution or solutions to this vexing problem.

Jan 1, 1967

Modern coal cleaning technologies have allowed coal preparation facilities to become quite efficient at removing sulfur compounds, waste rock and low grade coals from run of mine coal. Up to 50% of the raw mined coal stream may end up as refuse, particularly when the coal originates from longwall mining operations, or is high in partings, rock and impurities. The refuse materials vary from coarse materials removed by physical screening to very fine materials removed by floatation and density separation processes. Coal refuse piles are also known by a variety of other names including "waste dumps", "gob piles" and "slate dumps". The potential hazards of improperly reclaimed refuse include contamination of surface and groundwaters by acidic leachates and runoff, erosion and sedimentation into nearby watersheds, spontaneous combustion, disturbance of topsoil borrow areas, and damage from landslides should large slope failures occur. Many of these problems have been particularly acute for abandoned refuse piles, and modern regulations attempt to minimize the environmental impact of coal refuse disposal operations.

Jan 1, 1993