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By David Whalen

Mobile equipment in oil sand mining operations experience more maintenance problems than similar equipment in other surface mines, due to soft underfoot conditions. Oil sand properties are known to vary with temperature, bitumen content and previous loading cycles. One of the challenges is the widely variable underfoot pressure which supports shovels and trucks. In the case of a heavy hauler driving on in-pit roads, each tire is supported by a different ground stiffness resulting in an apparent uneven surface. Driving over uneven ground causes twist in the truck frame, which is transmitted to the dump body. Through a finite element analysis of a haul truck dump body, it was shown that slight frame twists produce localized stresses in the intersections of the floor stiffeners. These stresses are at times greater than those resulting from the maximum ore weight and are primarily responsible for cracking in these intersections. Syncrude maintains high quality haul roads, which are constructed of gravel, and makes every effort to keep the shovel pit roads as smooth as possible. This problem cannot be avoided through operational practices only and must also be accounted for in the design of haul truck bodies.

May 1, 2003

By B. McCosker

The choice of the appropriate delivery process for a project is often not adequately thought about. The industry needs to be prepared to break its preconceived mind-sets on delivery procedures. Industry should also be prepared, on a project by project basis, to commit to a critical review as to how the assessment and then selection of the best procurement method can best optimize the project outcome for both client and contractor. Conventional standards and biased reliances and experienced based preferences should be challenged. To achieve this requires a paradigm shift in attitude to both the process of tendering and the evaluation of tenders. Tender and contracting practices are dynamic and have moved away from solely cost based assessments. Tendering contracts arise imposing changed duties upon owners. Traditional contract delivery models have shifted, reflected in part by the trend towards relationship contracting. The categories of contract options are not closed. Many are but hybrids of other time-tested models. This paper considers options available for any brownfield or greenfield project. The principles outlined are translatable to supply, upgrade, operation and maintenance arrangements.

Jan 1, 2002

By E. R. Bauer

Prolonged exposure to noise can cause permanent damage to the auditory nerve and/or its sensory components, known as noise induced hearing loss (NIHL). It is the most common occupational disease in the United States today. The Pittsburgh Research Laboratory (PRL) of the National Institute for Occupational Safety and Health (NIOSH) is addressing NIHL in the mining industry through several research efforts. This paper presents a general review of NIHL, the status of NIHL in mining, the results of the longwall noise surveys, and a review of the longwall engineering controls research efforts.

Jan 1, 2008

By S. G. Malghan, J. P. Van Dillen

Introduction Some uranium minerals are paramagnetic and hence are amenable to concentration by high gradient magnetic separation (HGMS). This paper describes effects of the HGMS parameters-pulp velocity, field strength, matrix loading, and magnetic field gradient-on the product recovery and grade. Unsatisfactory separation of uranium minerals by HGMS is related to ore-specific properties, such as lack of liberation, fine dissemination of uranium minerals, uniform distribution of magnetic minerals throughout the ore matrix, and interference of fine-sized slimes. Experimental techniques to identify and resolve some of these problems are outlined. HGMS of Uranium Ores The mechanism by which uranium minerals are attracted to a magnetic field is either due to its magnetic susceptibility or its association with other minerals that are magnetic. Data on magnetic susceptibility of uranium minerals are scarce. The only reported data are for uraninite at 2360 X 10-6 cm3/mole. Povarennykh (Andres, 1976) concluded that the magnetic properties of minerals depend on: • Structure of the outer electron shell in a mineral with electropositive atoms; • Valence of the atoms; • State of the chemical bonds; • Type of coordination; and • Proportion of magnetic atoms (Fe, Mn, Cr, and Ni) in the composition of the mineral. However, information on the magnetic susceptibilities of the constituent atoms of a mineral alone does not suffice for evaluating the mineral compound as a whole. Most often, uranium minerals can be beneficiated by HGMS if they are associated with other minerals that are magnetic. This appears to be a more predominant mechanism by which the uranium minerals are beneficiated. Experimental A Sala-HGMS (Malghan and Subramanian, 1981), model 10-15-20, separator was used in the experiments. The matrix material-ferromagnetic stainless steel in the form of expanded metal or steel wool-was packed into a 38-mm (1.5-in.) diameter by 360-mm (14-in.) long canister. The matrix material occupied only a 150-mm (6-in.) length. The experimental set-up and slurry flow direction are described elsewhere (lannicelli, 1976). The response of uranium ores in the HGMS was studied by feeding well-dispersed slurry at 10% solids and examining the influence of process variables on selectivity and overall uranium recovery. The chemical and mineralogical characteristics of the ores under study are presented in Table 1.

Jan 12, 1983

By Charles A. Bankston, John C. Rowley, Robert J. Hanold, Joseph W. Neudecker

The basic concepts and processes of soil and rock melting as applied to excavation technology are reviewed. The electrically heated, small diameter prototype penetrator development sequence is presented. Emphasis is placed on the different methods of handling the fluid rock and soil melts and their significance in providing new solutions in hole support and debris handling problems. The refractory materials requirements, penetrator life and electrical heater technology are presented. Consolidating penetrators, which form stable glass-lined holes in low density rocks and soils, require no debris removal and will find applications in horizontal holes for utilities, cables, and pipeline installations. Extruding penetrators are being developed to make holes in dense, hard rocks. Melt is conditioned into a variety of debris forms, i.e., glass rods, pellets or rock wool, selected to match appropriate debris handling systems. Unique use in drilling into very hot rock or magma for geothermal exploration or production wells is projected. Some of the results of laboratory and field tests of these devices are compared with theoretically derived operating performance. Coring-consolidating penetrators for geological sampling in alluvium are projected to larger diameter self-propelled and guided coring devices for prospecting along proposed tunnel alignments. Application to the melting of annular shafts for pipeline support piles in difficult conditions such as permafrost has been scoped. Conceptual design studies of large diameter tunneling equipment have indicated the system contributions and economic aspects of rock melting relative to material comminution, wall and roof support and materials handling.

Jan 1, 1974

By M. G. Wallis

This report presents the results of a study to develop a detailed mining method design based on longwall mining with sublevel caving. The method is applicable to low-dipping coal seams 20 or more feet thick such as are found in the western United States. The report covers (1) the development and description of the mining method, (2) evaluation of the engineering feasibility of the design, (3) estimates of productivity and recovery, and (4) an engineering cost analysis and economic feasibility evaluation of the mining method design.

Jan 1, 1977

By V. N. Bryant

"1.0 SYNOPSISThe Colomac property, located 137 miles by air northwest of Yellowknife in Canada's NWT. will recover gold from 10,000 tons per day of open pit ore.The decision to proceed with the project was based on a mineable ore reserve of 16 million tons (including dilution) averaging 0.064 oz/ton. After an in-fill drilling program in the latter half of 1988, Colomac's mineable, proven and probable ore reserves were increased to 28 million tons averaging 0.056 oz/ton of gold.A feasibility study completed by Wright Engineers for Neptune Resources in December 1987 examined the possibility of vat leaching followed by C.l.P. and electrowinning. A second feasibility study completed by Wright in February 1988 demonstrated that a conventional agitated leach circuit using a finer grind justified the higher capital cost of this process. This study was accepted and formed the basis of the project authorization.Preliminary engineering commenced in April 1988 and detailed engineering was started in September of that year with the objective of a mine/mill start-up by early 1990.The short time period available to meet the project deadline was additionally challenging, as site access is either by plane year round, and winter road from early February to late March. Normal lead times for equipment design, specifications, quotations and bid analyses were not possible, if the winter road time-slot was to be met."

Jan 1, 1990

By Michael B. Cortie

The young field of nanotechnology has as its objective the design and construction of useful devices made of nanoscale materials. Objects or structures which have at least one important dimension in the range 0.5 to perhaps 50 nm may be considered to be in the nanoscale domain. These sizes lie far below the 200 nm or so that can be resolved with an optical microscope, and are closer in size to the 0.3 nm diameter of individual atoms. Nanotechnology, which is the study and exploitation of these tiny structures, is attracting keen interest at present. The excitement is motivated by the observation that control of matter at the nanoscale holds the promise of faster computing, better medicines, and smarter materials. In this paper, the physical phenomena on which this optimism is based are broadly discussed and explained. Where appropriate, examples of the rather different and curious properties of gold at the nanoscale are used to illustrate the points covered.

Oct 1, 2003

By S. J. Schatzel

Coal mine longwall face ventilation is an important component of the overall mine ventilation system. Increases in the production rate due to higher capacity mining equipment tend to increase methane emission rates from the coal face, which must be diluted by the face ventilation with a minimal opportunity for assistance from additional control equipment (i.e., surface boreholes). Increases in panel length, in some mines approaching 6,100 m (20,000 ft), and panel width provide additional challenges to face ventilation designs. Face ventilation can also be affected by communication with the methane-laden gob gas reservoir. Except in a two-entry system, belt air cannot be used to ventilate the face in the US, except in limited cases. This relatively recent requirement has further challenged the mining industry in maintaining adequate longwall face ventilation. To assess the effectiveness of current face ventilation practices, a face monitoring study was combined with a tracer gas test on a longwall face. The study was conducted at a US mine operating in a thick, bituminous coal seam with some self-heating tendencies. Multiple gob gas ventholes were located near the face and produced a small portion of ventilation air in their production flow. Initial results show that emission rates on the longwall face showed a very limited increase in methane concentrations from headgate to tailgate despite the occurrence of methane delays during monitoring. Increases in methane concentrations in the tailgate entry in the vicinity of the longwall face T-junction appeared to be produced primarily by gas flow from the gob, not from increased emissions from the face. Barometric pressure variations were substantial over the course of the study and varied on a diurnal basis, as is typical of many mining operations. Suggestions are forwarded for reducing longwall face methane concentrations.

Jan 1, 2012

By Ronald L. Bruening

IBC has developed a cost effective MRT process for the selective extraction and recovery of gold, copper, and a mixture of other base metals from mine leach cyanide solutions. This is a two-stage system in which the gold is first recovered selectively as a high purity salt. The copper is then recovered separately as a sulfate salt. The other base metals are then collected as a cyano anion concentrate. Three different SuperLig® materials are used. The first stage can be used alone on gold leach solutions where copper and other base metals are not a problem. The two or three stage system is used when the base metals build up in the leach solution, resulting in increased costs. The cyanide or cyanide/cyano anion concentrate can be recycled back to the leach solution until the build-up of other salts, etc. becomes too high, or this too can be controlled with a percentage bleed stream.

Oct 1, 2003

By Laura E. Beverage

The Changes 2008 Brought -MSHA recently posted a PowerPoint to its website which shows statistical performance information for fiscal years 2000 to 2008. -Interesting statistics: Fatality rate in Coal dropped by nearly 30% (.0348 to .0246 per 10,000 workers)

Jan 1, 2009

By R. G. Aspden, D. A. Colling

THE {120}(001) texture has been reported in near 50 pct Ni-Fe alloys <0.004 in. thick1,2 and in copper 0.014 in. thick.3 This texture is one of two types of secondary recrystallization textures observed to replace a cube texture matrix and is desirable in Fe-Ni alloys because of its unique magnetic characteristics.1,2 However, the conditions for and mechanism of the {120}(001) formation are not well understood.3 During an investigation of the influence of alloying elements on the magnetic characteristics of 49 pct Ni-Fe alloys with a sheet thickness of 0.014 in., we have observed the growth of {120}(001) secondaries when strong deoxidizers such as aluminum and calcium were present. It is believed that this observation in unique and provides additional insight with regard to the mechanism for {120}(001) texture formation. Three alloys were prepared with electrolytic iron and nickel and contained a nominal 49 wt pct Ni. Alloy A was a straight binary Fe-Ni alloy, whereas intentional additions of 0.013 wt pct Ca to alloy B and of 0.59 wt pct A1 to alloy C were made. Ingots were forged at 1100 C, hot-rolled to 0.150 in. gage, pickled, and cold-rolled to 0.014 in. Standard U-shaped magnetic test specimens were punched, deburred, sprayed with MgO, and annealed in ~50°C dew point hydrogen. Textures were identified with the aid of etch pits, the

Jan 1, 1970

To allow the controlled yielding of mine walls in order to reduce rock-burst hazards and reduce maintenance caused by excessive squeezing forces. Approach Rock bolts that elongate and continue to sustain a load, have been fabricated and tested. This device is an adoption of a concept originally developed in South Africa for use where unusually adverse conditions may warrant the added cost. How It Works A coupling in the rock bolt allows controlled elongation if the load increases beyond the bolt&apos;s design strength. (The load can build up either slowly, as during heaving, or rapidly, as before a rock burst.) The elon¬gation of one or more rock bolts surrounding a mine opening, allows the rock to move from its original position to c new position in a controlled manner. This movement relieves the rock stresses, and the mine opening reaches a new state of equilibrium. The elongatible coupling of the rock bolt consists of a

Jan 1, 1977

The purpose of this paper is to outline some aspects of the experimental worlr that has been carried out in the mineral dressing laboratory at M&apos;ount. Morgan during recent years.The subject matter has been dealt with under the following headings:1. Comminution of various mill products.2. The application of sulphur dioxide as a flotation reagent.3. Heavy-media separation.4. Bulk flotation of sulphide ores.COMMINUTION OF VARIOUS MILL PRODUCTSThe following data were cbtained by processing fractions of reserve grade ore.Granular TailingIn Table 1 are shown the results of tests on material representative of average grade tailing. In the first test (H1 ) the granular tailing was floated as received and in the second test (Ha) the tailing was ground prior to flotation.

Jan 1, 1952

By R. Switalski, M. Schafer, R. Pintabona, M. Kritzer, B. Lukajic, S. Janosko

Methane gas caused an eight-month shutdown of mining operations at the Mill Creek, Phase 3, Tunnel. The gas-related shutdown occurred as the tunnel was advanced to an approximate distance of 2,700 feet, which constitutes approximately18% of the total tunnel length. The construction of an emergency ventilation shaft, a comprehensive program of de-gassing wells and an expanded gas monitoring system were used to mitigate the gas condition. When complete, this tunnel will be utilized to convey and store combined storm and sanitary sewage collected from a portion of Cleveland, Ohio and ten suburbs. This paper will provide an overview of gas related remedial measures and explain how these measures were integrated into the project to ensure safe tunneling conditions.

Jan 1, 2007

By Christopher C. Jobes, Alan G. Mayton, Timothy J. Matty, Joseph P. DuCarme

Mining injury statistics show that a significant number of back, neck, and head injuries are linked to exposure from vehicle vibration. Use of a suspension seat is a common way to isolate the vehicle operator from the adverse effects of vibration exposure. Thus, researchers at the National Institute for Occupational Safety and Health1 – Pittsburgh Research Laboratory (NIOSH – PRL) performed laboratory studies on four passive and two semi-active seat suspension designs. These are typical of seat suspensions commonly found on large off-road heavy surface mining, construction and agricultural vehicles as either replacement or original equipment manufacturer (OEM) systems. One included a pneumatic (air bladder) spring mechanism. The fifth and sixth suspensions were a NIOSH magnetorheological (MR) semi-active damper design based on the pneumatic (air bladder) and one of the coil spring suspensions above. These suspensions were modified with a commercially available MR damper substituted for the OEM damper. These six seat suspension systems were tested and analyzed, for vertical vibration only, using the ISO 5007 Standard [1]. This paper describes the laboratory vibration tests using a MTS® shaker table and discusses the results obtained for the different suspension designs and highlights the rheonetic technology studied. Implications of the seat suspension designs relative to their capabilities for isolating vehicle operators from vibration exposure are discussed. Results for suspensions 1 through 3 showed frequencies of isolation from 2.1 to 3.0 Hz using the 40-kg (88-lb) mass and from 1.65 Hz to 1.8 Hz using the 80-kg (176-lb) mass. Suspension #4, in tests with only the 80-kg (176-lb) mass, showed an isolation frequency of 3.7 Hz. With the MR damper added to seat suspension #4, the peak transmissibility was lowered from 1.3 to 0.95 and showed a corresponding downward shift in frequency from 2.25 Hz to 1.4 Hz. In fact, the results for suspension #5 (the MR damper added to seat suspension #4), using test #3 conditions of the programmed control algorithm, showed isolation (attenuation of transmitted vibration) throughout the test frequency range from 1.0 to 6.0 Hz.

By A. Kapito

The ferrite-pearlite microstructure is the most popular microstructure for alloys used in structural applications, including railway wagon wheels. These alloys have been designed through alloying and thermo-mechanical processing to have a refined microstructure. Ferrite-pearlite alloys are low cost, weldable, have good fabricability, and are reliable under extreme conditions. Given these performance attributes, it seems unlikely then that their dominant position as structural steels would ever be challenged by alternative microstructures. One major achievement in the development of ferrite-pearlite steels has been in the refinement of their interlamellar spacing to very fine distances of the order of < 0.3 um. A refined microstructure increases the hardness of the alloy, thus increasing its life under wear conditions. The interlamellar spacing in pearlitic steels has, however, been refined almost to its theoretical limit. The increasing demand for speed and increased axle loading on railway wagons requires the use of stronger, tougher, and more durable materials. This has opened the window for the development of novel bainitic steels. Bainitic alloys have a higher level of microstructural refinement than pearlitic ones. They have shown to have good wear resistance and rolling-contact fatigue resistance, and high toughness. This paper will discuss the progress to date on the development of bainitic railway wheel alloys. Four alloy chemistries have been chosen for possible further development.

Jan 1, 2012

By Mario Bergeron

L&apos;exploration géologique pour les EOP (EOP: platine, palladium, iridium, osmium, ruthénium, rhodium) requiert avant tout des méthodes appropriees à la mesure de ces élémenIs. L&apos;approche analytique choisie doit tenir compte de plusieurs facteurs, les plus importants étant: le type de materiel analysé, sa representativite, la sensibitite de la methode et les cotits reliés à son utilisation. Dans cette optique, plusieurs démarches ana/ytiquessont possibles, toutes requérant une étape de préconcentration. L &apos;une des plus adéquate consiste à effectuer une préconcentration par fusion plombeuse suivie d&apos;une analyse par émission au plasma, cette procédure permettant de mesurer Ie platine, la palladium et Ie rhodium à des couts compétitifs (15 $/échantillon). Advenant 10 presence de teneurs appréciables de l&apos;un ou plusieurs de ces éléments, une préconcentration par fusion au sulfure de nickel suivie d &apos;une analyse par activation neutronique assure alors la mesure de tous les EGP ainsi que celie de l’or (90 $/échantillon). Il est important de noter que Ie nickel, ades teneurs superieures à 4%, interfère au cours de l&apos;étape de préconcentration par fusion plombeuse, ce qui se traduit pas sous-dosage des concentrations en platine, effectivement presentes dans l&apos;échantillon. Ainsi, les géologues à la recherche d&apos;EPG dans des environnements géologiques riches en nickel devraient s&apos;assurer que l&apos;analyse utilise, au cours de l&apos;étape de préconcentration, une fusion au sulfure de nickel.

Jan 1, 1990

Mining and the related extractive and processing industries are chiefly responsible for America&apos;s high standard of living. Enormous quantities of sand and gravel, limestone, copper, iron and a myriad of other mineral commodities are required to sustain our growing nation. However, the mineral deposits, both domestic and foreign, are becoming increasingly difficult to find. Adding substantially to the problem, is the fact that the conditions are worldwide. Foreign politics are increasingly affecting mineral commodity availability. Figure 1, taken from Bureau of Mines, "Status of the Mineral industries 1976" illustrates our dependency (in some cases total) on foreign sources for vital mineral commodities. While few nations are capable of exerting an OPEC-like influence on any one mineral commodity, the threat of cartel arrangements and related control strategies is evident. Nationalization of entire industries, once they become self-sufficient, is also exerting a disruptive influence on a large portion of the mineral industries.

Jan 1, 1977

By Sadettin Bagdatli, Ali Kahriman, Umit Ozer, Alper Celtikci, Yucel Karakus

Due to population growth and rapid urbanization in Turkey, the need for the construction of residential units, transportation and infrastructure facilities has become increasingly more pressing. Since rock units encountered in the surface and underground in the construction of the subway, infrastructure and housing facilities, it is a necessity to use blast excavation methods. In recent years, large housing construction projects have been carried out especially in Turkish metropolitan areas, involving foundation excavations giving rise to great amounts of earthmoving. Since rock units encountered during foundation excavations are usually hard and solid, excavation with conventional machinery proves to be inadequate and unproductive, hence the necessity for the application of blasting technology.

Jan 1, 2014