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By Charles Knilans, Tassos Grammatikopoulos, Nicole Hoffmann

"Twin Metals Minnesota LLC, (TMM) has recently completed a prefeasibility study evaluating the development and operation of an underground copper (Cu), nickel (Ni), platinum (Pt), palladium (Pd), and gold (Au) mining project on the Maturi deposit in northeastern Minnesota.The Maturi deposit is a magmatic Cu-Ni-sulphide deposit occurring along the basal contact of the South Kawishiwi intrusion, comprised of heterogeneous troctolites to gabbros forming a tabular body designated the BMZ (basal mineralized zone). These rocks provide the major gangue mineralogy (plagioclase, olivine, and clinopyroxene) with local, minor rock-forming orthopyroxene, biotite, magnetite, and ilmenite. Altered silicates exist within local fracture and/or alteration zones, which are commonly associated with minor faults in the regional area. The Maturi deposit is comprised of four main mineralized zones within the BMZ, referred to as Stage 1, Stage 2 (S2), Stage 3 (S3), and Upper Heterogeneous. Chalcopyrite, cubanite, pentlandite, and pyrrhotite are mainly hosted within the S2 and S3 units, with talnakhite frequently occurring within the S3 unit.A cross-discipline approach combining geology, geochemistry, metallurgy, QEMSCAN™ mineralogy, and mine planning has been implemented to develop a preliminary geometallurgical model and life of mine metallurgical performance forecast. This paper provides an overview of the methods that were used to develop the model and forecast, and discusses the advantages of such a model in project development and evaluation.INTRODUCTIONThe TMM Project proposes mining a copper-nickel-palladium-platinum-gold-silver (Cu-Ni-PGM) magmatic sulphide deposit situated in the Duluth Complex of northeastern Minnesota, USA. The prefeasibility study proposes a 45,000 million tonnes per day mine and concentrator facility to produce two saleable concentrates. The mine will access two separate deposits, Maturi and Maturi Southwest. Saleable concentrates are the final products of the sequential flotation plant where a high grade Cu concentrate is produced followed by a Ni concentrate."

Jan 1, 2015

Caving of the second lift of the E26 orebody at Northparkes Mines was monitored with a comprehensive package of instrumentation, including an ISS seismic monitoring system. Seismicity was collected by an array of 19 triaxial accelerometers and 9 uniaxial geophones, giving a high quality seismic data set. The seismic response to block caving at Northparkes has been divided into two papers. The first paper focuses on the seismicity during undercutting. The second paper deals primarily with the seismicity during cave propagation during initial cave production. In this paper, traditional seismic monitoring concepts are applied to seismicity during cave mining. More than 40 000 seismic events were recorded during cave undercutting between February and January 2004. Events up to local magnitude +1.3 were recorded near the mine during undercutting, with event rates of up to 500 per day. Analysis of frequency-magnitude distributions, S-wave to P-wave energy, and temporal variations in event magnitude all gave insight into the seismicity recorded. In addition, a new technique, called apparent stress time history, was shown to be sensitive to stress change from undercut blasting, and useful to identify significant periods during cave development. A significant difference was identified between the cave back location and the halo of seismic events above the cave. Throughout the undercutting, the a seismic zone of loosening was typically 50 to 70 metres in vertical thickness. Based on the seismicity, a stress driven rock mass failure model is proposed. Early in the undercutting, seismicity and movements in the seismogenic zone were directly triggered by stress change from undercutting. Towards the end of undercutting, seismicity was virtually uncorrelated with undercut blasting, and likely due to the onset of cave initiation.

Jan 1, 2008

By Jesús E. Gómez

This work is a continuation of a paper presented in the 32nd DFI Annual Conference, Colorado 2007, titled ?Hollow Core Bar Micropiles - Design parameters interpreted from 260 load tests.? The first paper presented the results of the verification and proof tests performed for the retrofit of two bridges with hollow core bars that used 260 micropiles. It included an interpretation of the unit bond values in the different soils where micropiles were installed. Recently two additional bridges within the same geological environment were also retrofitted using 144 hollow core micropiles. This paper includes the interpretation of the additional data from the proof tests performed and refines recommended values for design of hollow core bar micropiles in soils similar to those encountered in these two projects. The authors believe that the data collected will significantly add to the relatively small existing database on micropile tests and may also be useful during implementation of the LRFD design methodology.

Jan 1, 2008

By George S. Rice

The following paper was presented at an International Conference on Mine Safety Research held at Dortmund, Germany, September 23-28, 1935, inclusive. This conference was attended by representatives of Belgium, France, Germany, Great Britain, and the United States ands by invitation, Czechoslovakia, Poland, Spain, and Russia. The first international conference of representatives of mine-safety, research stations was held the United States Bureau of Mines Pittsburgh Experiment station in 1912 .4/

Jan 1, 1936

By Francisco Anglade

Dado que la simulación digital es una herramienta auxilar para los ingenieros de procesos -en tanto evalúa la factibilidad de un flowsheet propuesto y predice el efecto de una modificación para un flowsheet existente, su importancia también se extiende también a la evaluación de alternativas para las estrategias de control en los circuitos de la planta. En ese sentido, el presente trabajo señala los beneficios económicos y técnicos obtenidos en la planta San Rafael mediante el empleo de simuladores en los circuitos de molienda, chancado y concentración gravimétrica, los cuales permiten corroborar los cambios efectuados u optimizar los circuitos señalados de forma simple y rápida.

Sep 9, 2007

(This paper reviews the reasons for and the principles followed in designing and constructing complete new surface works at the mine of the Zinc Corporation Limited, Broken Hill, New South Wales, and describes the layout, plant, buildings and services.)The Zinc Corporation mine produces high grade lead, silver and zinc sulphide ore. Lead and zinc concentrates are sent by rail to Port Pirie, where the lead is smelted and the zinc concentrate is shipped to Tasmania, England and other overseas countries.Some time ago consideration was given to the advisability of sinking an additional shaft. For some years the old main shaft had been working at full capacity and developments underground had indicated that the mine would eventually be capable of an output greater than that which could be handled through the shaft. It was therefore decided to sink a new main shaft and the site chosen was in footwall country 900 feet south of the old main shaft. The reason for the move south was so that the new shaft would be opposite the centre of gravity of the ore-bodies at depth. The size of the new shaft is 27 ft. ,6 in. x 15 ft., and the work was put in hand early in 1936.It was intended to haul the whole mine output through this shaft, which was 1,600 feet from the mill then operating. An extensive conveyor system thus became necessary unless a new mill was built near the shaft. A careful study of the situation was made by the management and consideration was given to requirements for expansion, the condition of...

Jan 1, 1940

By John C. Machisak

The National Safety Competition is sponsored and conducted annually by the Bureau of Mines, U.S. Department of the Interior, to give greater impetus to the building of programs safeguarding the employees of the mineral industries from disabling work injuries. The results of the 1960 National Safety Competition are presented in this publication. Mines and quarries that were awarded the Sentinels of Safety trophy for the best safety record in their competitive group and those mineral operations that ranked second, third, fourth, and fifth in the competition are listed with a summary of their achievements in preventing disabling work injuries. In addition, this publication presents statistical data on disabling work-injury experience in all other mines and quarries participating in the annual competitions.

Jan 1, 1962

By Gordon M. Matheson

The factors which control chimney subsidence sinkhole development in weak rock were assessed by analyzing the characteristics of approximately 3000 chimney subsidence features along the Colorado Front Range. The area of study included features developed over abandoned mines in the Colorado Springs Coal Field, the Boulder Coal Field, and the Foothills District. The approximate locations of the areas studied are shown in Figure 1. Data were collected for sinkholes occurring over both room and pillar, and retreat mining areas in coal seams with a wide range of dips. The location, size, and approximate time of development of each sinkhole were documented. From these data, relationships were developed which describe the time rate of observable sinkhole development and the relative location of sinkhole development with respect to mined height, overburden thickness, and type of mining for relatively flat-lying coal seams. In addition, the observed locations of sinkhole development over steeply dipping coal seams were assessed for portions of the study area.

Jan 1, 1986

By V. Labiouse, M. Jaboyedoff

GIS documents are of great interest for a quick and low-cost determination of areas endangered by rockfalls. They allow (i) the detection of potential instabilities from steep slopes and cliff areas, and (ii) the preliminary estimation of potential run-out areas by means of a so-called cone method. After the presentation of the tools used to compute these areas, the paper focuses on two methods developed for a preliminary hazard mapping, one at regional scale and the other at local scale. Mittels GIS-Dokumenten können von Steinschlag bedrohte Gebiete schnell und kostengünstig ermittelt werden. Die sogenannte Kegelmethode erlaubt die Erkennung potentiell instabiler Zonen von Steilhängen und Felswänden sowie eine erste Einschätzung der möglichen Reichweiten. Nach der Vorstellung der zur Berechnung der bedrohten Gebiete benötigten Hilfsmittel stellt der Artikel zwei Methoden zur vorläufigen Gefahrenkartierung in lokalem und regionalem Maßstab vor. Les SIG sont très intéressants pour une détermination rapide et peu onéreuse des zones affectées par des chutes de blocs. Ils permettent une détection des zones potentiellement instables et une estimation sommaire des zones de propagation des blocs par une méthode dite des cônes. Après la description des outils utilisés pour définir ces zones, l’article expose deux méthodologies élaborées pour un zonage préliminaire du danger, l’une à l’échelle régionale et l’autre à l’échelle locale.

Jan 1, 2003

By J. Asfahani

"The Schlumberger configuration used in geoelectrical sounding is slightly adapted here to obtain reliable data for both shallow and deep penetration depths from the same survey. In this configuration, two kinds of current electrode half-spacings are used: the first enables construction of vertical electrical resistivity sounding (VES) curves for shallow depths (<50 m), and the second for depths =250 m. For a given VES location, two field curves are measured and interpreted using two standard approaches. Practical characteristics of such a modified configuration are illustrated with two field applications in Syria. The first aims to characterize the structure of Quaternary and recent deposits in the Al-Ghab depression region, and the second deals with exploration for phosphatic sedimentary units in the Al-Sharquieh mine. La configuration de Schlumberger normalement employée dans les levés géoélectriques a été légèrement modifiée afin d’obtenir des données fiables à faible et forte profondeur durant le même levé. Dans cette nouvelle configuration, deux types de demi-espacements des électrodes sont utilisés : le premier permet le développement de courbes de sondage de résistivité électrique verticales (REV) pour les faibles profondeurs (<50 m), et le second atteint des profondeurs =250 m. Pour une localité REV donnée, deux courbes de champs sont donc mesurées et interprétées grâce à deux approches standardisées. Les caractéristiques pratiques de cette configuration modifiée sont illustrées par deus exemples d’application en Syrie. Le premier vise la caractérisation de la structure des dépôts Quaternaires et récents de la région de la dépression d’Al-Ghab, et le second traite de l’exploration pour des unités phosphatiques sédimentaires à la mine Al-Sharquieh."

Jan 1, 2009

By M. I. Al-Wakeel

Nile sediment was collected as a waste from one of the water treatment plants in Cairo, and subjected to petrographical investigation and granulometric, chemical, and mineralogical analyses. It was expected to find diatomite in that sediment but it was a surprise to find that the diatomite content amounted to about 52.01% by volume in addition to quartz, orthoclase and clay minerals. The latter are represented by montmorillonite and illite minerals. The sediment is light gray in color, soft and has low density and high surface area, such density and surface area generally decrease with temperature. The sediment absorbs 317% of its weight in water. The diatomite skeletons are the main factor responsible for its high porosity producing microporosity and low density, and these particles are concentrated in the very fine silt size fraction (11x2µm). The common diatoms in such sediment include Cyclotella ocellata Pant, and Melosira granulata (Ehr.) Ralfs. It seems that this Nile diatomaceous sediment has many advantages over the fossil diatomite, such as Fayium diatomite in Egypt, with the absence of carbonate minerals that require grinding and calcination those cause destruction of the cellular structure and energy consumption. This Nile diatomaceous sediment can be processed using sequential classification to obtain diatomite concentrate of 88.8% grade at 90.6% recovery, and a middling product of 19.4% grade and 5.8% recovery. The suggested flow sheet is quite simple to produce diatomite product for different industries at a low cost. The unusual particulate structure and chemical inertness make diatomite an ideal mineral to be used as functional filler in a wide range of industries, and as catalyst carriers and insulating material. Key words: Egypt, Nile sediment, Diatomite, Beneficiation, Sedimentation, Classification.

Jan 1, 2008

The Bureau of Mines studied blast-produced ground vibration from surface mining to assess its damage and annoyance potential, and to determine safe levels and appropriate measurement techniques. Direct measurements were made of ground-vibration-produced structure responses and damage in 76 homes for 219 production blasts. These results were combined with damage data from nine other blasting studies, including the three analyzed previously for Bureau of Mines Bulletin 656. Save levels of ground vibration from blasting range from 0.5 to 2.0 in/sec peak particle velocity for residential-type structures. The damage threshold values are functions of the frequencies of the vibration transmitted into the residences and the types of construction. Particularly serious are the low-frequency vibrations that exist in soft foundation materials and/or result from long blast-to-residence distances. These vibrations produce not only structure resonances (4 to 12 Hz for whole structures and 10 to 25 Hz for mid walls) but also excessive levels of displacement and strain. Threshold damage was defined as the occurrence of cosmetic damage; that is, the most superficial interior cracking of the type that develops in all homes independent of blasting. Homes with plastered interior walls are more susceptible to blast-produced cracking then modern gypsum wallboard; the latter are adequately protected by a minimum particle velocity of approximately 0.75 in/ sec for frequencies below 40 Hz. Structure response amplification factors were measured; typical values were 1.5 for structures as a whole (racking) and 4 for midwalls, at their respective resonance frequencies. For blast vibrations above 40 Hz, all amplification factors for frame residential structures were less than unity. The human response and annoyance problem from ground vibration is aggravated by wall rattling, secondary noises, and the presence of airblast. Approximately 5 to 10 pct of the neighbors will judge peak particle velocity levels of 0.5 to 0.75 in/sec as "less than acceptable" (i.e., unacceptable) based on direct reactions to the vibration. Even lower levels cause psychological response problems, and thus social, economic, and public relations factors become critical for continued blasting.

Jan 1, 1980

By W. A. Calhoun

This report gives results of metallurgical investigations performed by the Bureau of Mines on mineral samples taken during April 1959, from Hawaiian bauxite deposits on the islands of Kauai, Maui, and Hawaii. The bauxite samples were tested at the Bureau&apos;s Rolla Metallurgy Research Center, Rolla, Mo., to determine if alumina could be extracted. The results were encouraging. Extraction of the alumina by the American Bayer type digest of crude ore samples from Kauai, Maui, and Hawaii recovered 78.8, 73.1, and 70.0 percent, of the total alumina, respectively. These recoveries were increased to 82.8, 85.5, and 79.5 percent by modifying the treatment, which consisted essentially of calcination and weak caustic desilication to provide a residue. The residue was then treated with calcium oxide and digested in a strong caustic solution to extract the alumina.

Jan 1, 1962

In preparing this paper, the writer hopes to achieve two main objects. Firstly, an indication of the desirable features of coke from the viewpoint of a blast furnace operator should be of assistance and value to those connected with coal and coke research, coal mining, the manufacture of coke and the production of iron. Secondly, it is hoped that the conclusions and opinions expressed herein, which are known to be of a controversial nature, will promote some discussion and thought. In this way, other workers may see fit to contribute and enlarge our general knowledge of Australian coke and its behaviour in blast furnaces.Those properties of coke that are considered to be of importance to blast furnace operation will be examined. Although broadly speaking, the composition and characteristics of coke are inherent in the coals used, any special features of coal preparation and carbonization that affect the resultant coke will be discussed. An attempt will also be made to indicate the effect on blast furnace operation of significant irregularities in these properties.THE FUNCTION OF COKE IN A BLAST FURNACECoke has four important functions in a blast furnace:1. To reduce the oxides of iron and other elements to metal and to provide the carbon absorbed by the iron.2. To supply the necessary heat for the process.3. To provide an open supporting structure in which the descending ore and limestone lie exposed to the action of the ascending gas.4. To provide voidage in the bottom of the furnace, so that iron and slag can accumulate in the hearth.

Jan 1, 1957

By V A. Tsukerman

Prospects a new energy saving method for an efficient destruction of the sturdy and hard materials (rocks, ores, frozen soils, concrete blocks, etc) û the Electric Pulse Discharge (EPD) method of materials destruction for green processing in mining and processing of mineral raw materials are considered.The EPD-technologies give additional possibilities for solving ecological problems at the expense of increase of integrated approach of utilisation of minerals and industrial wastes. The scientific and technical level of executed development of EPD method is sufficient for organisation of design work to develop substantially new equipment. A number of plants have been developed and tested, including plants for processing raw material with minerals of jewels, plants for selection of mica from rocks, and plants for processing the merging of artificial mica.

Jan 1, 2002

By K. A. Lewandowski

Agglomeration techniques are widely used by industry to form fine particles into larger masses that are easier to handle and process. One area where agglomeration is potentially useful is in heap leaching operations. With-out agglomeration, fine particles travel through the heap, clogging the spaces between the larger particles and resulting in poor leach solution flow. Poor flow of leach solution will result in long leach rates and/or decreased metal recovery. Agglomeration immobilizes the fine particles and therefore improves heap permeability to fluid flow. Additional additives (binders) are needed to prevent agglomerates from breaking up as leaching solution percolates through the heap. Type II Portland cement and lime are two well-known binders used in gold and silver leaching, but these are limited to alkaline leaching environments. Various other products have been tested as binders, including polymers. This paper summarizes the benefits of agglomeration in heap leaching and the results obtained from the testing of several different agglomeration binders in heap leaching operations.

Jan 1, 2009

This is the third in a series of reports on properties of commercial motor fuels, made in accordance with a cooperative agreement between the Cooperative Fuel Research (C. F. R.) Committee and the Bureau of Mines of the Department of the Interior. The first report gave data on motor gasolines sold during the winter of 1935-36.3/ The second report gave the same data for motor gasolines sold during the summer of 1936)4/ As was the case with the first cooperative gasoline survey, reports were received for some areas from only one company and in other areas from two companies that did not in all instances report on the same brands of gasoline. In still other areas reports were received from five or six companies on the same brands of gasoline. Thus, it can be seen that data on gasolines are unequal in regard, to the number of reports that were averaged in calculating the data shown in table 1. The data from the Pacific Coast were averaged by the Pacific Coast technical group before submission and are published exactly as they were submitted.

Jan 1, 1937

This is the third in a series of reports on properties of commercial motor fuels, made in accordance with a cooperative agreement between the Cooperative Fuel Research (C. F. R.) Committee and the Bureau of Mines of the Department of the Interior. The first report gave data on motor gasolines sold during the winter of 1935-36.3/ The second report gave the same data for motor gasolines sold during the summer of 1936)4/ As was the case with the first cooperative gasoline survey, reports were received for some areas from only one company and in other areas from two companies that did not in all instances report on the same brands of gasoline. In still other areas reports were received from five or six companies on the same brands of gasoline. Thus, it can be seen that data on gasolines are unequal in regard, to the number of reports that were averaged in calculating the data shown in table 1. The data from the Pacific Coast were averaged by the Pacific Coast technical group before submission and are published exactly as they were submitted.

Jan 1, 1937

By John R. Bartels

This U.S. Bureau of Mines report describes the development, system by system evaluation, and preliminary surface testing of a flywheel-powered shuttle car (FPSC). The use of a self-contained flywheel-power source has the potential to eliminate the numerous safety and routing problems associated with tethered mobile equipment. An alternative to conventional power cable systems was developed consisting of the world&apos;s fIrst seven-rotor stacked flywheel system capable of storing 6 kW·h of energy at 16,700 rpm. Numerous interdependent systems were necessary for successful interfacing with a conventional shuttle car. Each of these systems was evaluated and tested individually. Finally, the entire shuttle car was surface tested. The tests indicated that the flywheel energy system can function and operate a shuttle car. The economics of the system and the design of required support systems were not addressed in the project.

Jan 1, 1991

By Lucien Weber

In the Shanghai area, the soil conditions are such that bearing piles have become an essential foundation part of the new highrise buildings. In order to reduce the settlements under the high working loads of about 2300 kN/pile, the Chinese building authorities require the pile tip to penetrate into the compact sand layer, situated at approx. 60-70 m depth. No H-piles have yet been tested under these conditions in Shanghai. This paper describes the driving of 8 H-bearing piles with 4 different shapes and with lengths varying from 45 to 75 m. Dynamic measurements are performed during driving and after a wait time of approx. 40 hours in order to assess the change in bearing capacity in function of time and in order to get an idea about the resistance distribution along the piles by using a stress wave analysis program (CAPWAP). One pile is equipped with channels between the flanges for executing verticality measurements with an inclinometer. However, this test has not yet been performed. One month after driving, two piles of 75 m length are statically loaded both in vertical and in horizontal directions.

Jan 1, 1987