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By P. Bousquet

Acid mine drainage (AMD) is a serious environmental problem that preoccupies the Canadian mining industry. Considerable amounts of money are spent every year in an effort to prevent or reduce the acid mine drainage phenomenon. AMD occurs when sulphide minerals (e.g., pyrite) contained in rock are exposed to air and water and subsequently oxidize to produce low pH water. This acid effluent has the potential to mobilize any heavy metals contained in the rock. Coating the sulphide minerals with silicates is a new promising technology to reduce AMD. Pyrite is treated with a solution containing H2O2, sodium silicate and a buffering agent. H2O2 oxidizes a small part of pyrite producing ferric iron (Fe3+) ions. These ions subsequently react with the silicate ions to produce ferric hydroxide-silica that precipitates on the pyrite surface producing a passive coating. This silicate coating can protect the grains of pyrite from oxidation. This paper presents a series of experiments that confirm that silicate coating can considerably reduce AMD.

Jan 1, 2002

By J Darbritz

"This paper details the events leading up to a slope failure that occurred at Kalgoorlie Consolidated Gold Mines (KCGM) and the remediation method executed using rope access specialists.n January 2016, KCGM Fimiston Pit experienced a double bench wall failure where approximately 80 000 t of material fell from the wall that blocked access to a ramp and caused minor damage to equipment.The event was triggered by heavy rainfall and occurred along unfavourable eastward dipping structures that lead into weaker shale/porphyry bands, which in turn left more material on the face. A remediation plan was formulated that would allow for the continuation of open pit operations while a full geotechnical assessment of the failure area could be conducted. This was accomplished by means of rope access specialists who abseiled down the wall and blasted off the remaining overhang using a portable drill rig and prepackaged explosives.This paper provides a brief overview of the KCGM operations, how the instability was identified and monitored, details of the failure event, outcomes of the geotechnical assessment and details on the remediation work.Citation:Graf, C and Sullivan, R, 2016. The Journey to Steepening the Pit Slope Angle - Advancing the Effectiveness of Wall Control, in Proceedings Ninth AusIMM Open Pit Operators' Conference 2016, pp 104–114 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 15, 2016

The Determination of Sound Exposures (DOSES) software was developed by the National Institute for Occupational Safety and Health (NIOSH) specifically for use by mine management and safety personnel. DOSES simplifies the record-keeping and analysis associated with time-motion studies and worker noise exposures, making it easier to identify and solve noise problems. The software relies on a time-motion study that profiles the worker?s daily activities. At the same time, noise measurements are collected with a dosimeter or sound level meter (SLM). Observations about the worker?s location and tasks or other activities are recorded along with times and durations so they can later be matched up with the noise data. After the completion of a time-motion study of the worker?s daily tasks and locations (possible noise sources), which measures the worker?s noise exposures during the recorded events, the information is entered into DOSES. The program then displays information about the worker?s accumulated noise dose over time.

Jan 1, 2009

By A. Brown

This report details work performed and results obtained in a study of the water management aspects of oil shale mining and retorting in the Piceance Creek Basin. Three specific sites were investigated, and optimal water management systems for both conventional and in-situ extraction processes were generated. Water-related legal and environmental constraints on development were identified and the water management schemes were developed in compliance with these regulations. Limitations on shale oil production implied by limited water supplies were evaluated. Potential Basin-wide effects of development were evaluated using a computer model, and mitigation strategies were developed. Recommendations for additional investigation and analyses were presented.

Jan 1, 1977

By V. Velicka, J. Ptacek, R. Snuparek, P. Konecny, G. Takla

Coal mining in Ostrava-Karvina coalfield is being accompanied by rockbursts. 82 rockbursts occurred within the period between 1990 and 2002. Natural and technological factors from these rockbursts were collected and analysed. They confirmed that rockbursts are complex geomechanical events and that the relations between co-acting technological and natural factors are very complicated. Der Abbau in dem Ostrava-Karvina Steinkohlenrevier wurde von Anfang an durch Gebirgsschläge begleitet. 82 Gebirgsschläge in dem Zeitabshnitt von 1990 bis 2002 erfolgten. Die Angaben über natürliche und technische Faktoren der Gebirgsschläge wurden gesammelt und analysiert. Es wurde bestätigt, dass die Gebirgsschläge komplexe geomechanische Phänomene sind und dass die Beziehungen zwischen den zusammenwirkenden Faktoren sehr kompliziert sind. L´abattage d´houille dans le Bassin houiller d´Ostrava-Karvina est accompagnée par les coups de terrains. 82 coups de terrains s´étaient produit dans la période entre 1990-2002. Les données sur les facteurs naturels et techniques ont été ramassées et analysées. Les résultats ont corroboré que les coups de terrains sont des phénomènes géoméchaniques complexes. Les relations entre les facteurs techniques et naturels coopérants sont très compliqués.

Jan 1, 2003

By AMIR EHSAN KIANFAR, Moritz Ziegler, TOBIAS HARTMANN, ELISABETH CLAUSEN

Accurate positioning information is a central step in the process of increasing automation and digitalization in the mining industry. Underground mine environments are prime examples for GNSS-denied environments that pose several additional challenges for the employed indoor positioning system (IPS). This work presents an ultra-wideband (UWB)–based system specifically tailored for underground mine environments. Initially, the UWB technology is reviewed and basic concepts of IPS are explained. Both software and hardware are described in detail, including positioning algorithms, electrical circuitry, and the mining-compatible enclosure. Finally, the results from field tests in an underground mine are presented and positioning performance and the influence of dilution of precision (DOP) on positioning results are empirically evaluated. The results show that the localization errors are mostly below 1 m. Individual zones of high localization errors are suspected to be caused by noise interference. Significant DOP influence due to the mining drift geometry can be confirmed. The system shows promising localization results for different mining applications, while influences negatively impacting the accuracy are presented as items for future research.

Jul 7, 2023

By Denis Tepavac, Mark Trim

Structural performance of fiber reinforced concrete (FRC) depends on its ability to carry tensile forces after cracking. Australian Standards AS5100-2017 and AS3600-2018 are the only available design standards that establish a test procedure to determine strength and toughness of an FRC in direct tension. Direct tensile testing of fiber reinforced shotcrete samples was performed to determine if the model and guidelines in AS5100/3600 were applicable to shotcrete; all previous testing was from cast samples. In addition to direct testing, micro CT-scanning was also performed. The paper presents tests performed, results, and how the tests could be used on future projects. In addition, a brief summary is provided of the guiding structural mechanics used for estimating residual tensile strength and test methods utilized to verify those estimates.

Jun 13, 2023

The panic bars (and associated linkages and electrical circuitry) that are defined in this document are a machine operator-actuated control for the emergency deenergization of the tram motors on self-propelled, electric and diesel face equipment; including haulage equipment such as shuttle cars. There are nine basic types of panic bars (and several variations) that are recommended in this document, but all of the panic bars are characteristically of the ?fire door? type that is frequently encountered on outside exit doors of many public and some commercial buildings. It is also the intent of the following panic bar designs that, when emergency brakes are added to the face equipment machinery for which they are required, that they be designed and hooked up so that actuation of the panic bar will result in automatic application of the emergency brakes (immediately following the deenergization of the tram motors). The following panic bar design requirements are a restatement of the proposed requirements defined in the Federal Register, requirements cited in "Guidelines for the Design and Installation of Devices for Deenergization of Self -Propelled Electric Face Equipment/Automatic Emergency Brake s II by C. E. Lester and J. D. Greenhalgh of MESA, and Bendix recommendations that were formulated as a result of discussions with personnel at the various machine manufacturers and underground coal mines that we surveyed, discussions with G. L. Judy (our consultant), etc:

Jan 1, 1974

By Chris Nelson

Two pieces of European Union (EU) legislation together establish requirements for protection against risks from vibration at work. The vibration directive1 specifies duties of employers to protect workers from risks from exposure to vibration; the machinery directive2, specifies duties of manufacturers and suppliers regarding the safety of machinery marketed in the EU. This paper discusses both directives and the standardisation programmes that support them. It also addresses the implementation of these requirements in Great Britain. Employers’ duties: the vibration directive This directive requires employers to assess and control risks to health and safety arising from hand-arm vibration (HAV) and whole-body vibration (WBV). Member States were required to implement the directive in national legislation by 6 July 2005. Employers are required to eliminate vibration risk at source, or reduced to a minimum. The duties include: assessing risk and exposure; planning and implementing the necessary risk control measures; providing and maintaining suitable work equipment; providing workers with information and training on risks and their control; and monitoring and reviewing the effectiveness of the risk control programme. Daily exposure exceeding a specified action value triggers a requirement for a programme of technical and organisational measures to minimise vibration exposures and the resulting risk, and the provision of health surveillance. Exposures above a specified limit value are prohibited. When conducting their risk assessments, employers are required to “assess and, if necessary, measure” the vibration exposure of workers, for comparison with the action and limit values. Vibration measurement in the workplace is not expected in all cases and the use of vibration information from equipment manufacturers is specifically mentioned. This provides a link with the machinery directive (see below). Manufacturers’ and suppliers’ duties: The machinery directive The machinery directive, first introduced in 1989, is intended to remove barriers to trade. It puts duties on manufacturers and suppliers who place machinery on the European market to design their products to eliminate or reduce risks to health and safety and to warn the user of any residual risks, providing information required for safe use (for example, operator training, maintenance and selection of consumables). There are specific requirements for minimising risk from vibration in the design and construction of the machine and, in the case of hand-held, hand-

Jan 6, 2006

By H. Savasci, G. Yarim, J. S. Chung

As part of ongoing deep-ocean mining research, hydraulic transport systems as well as status of deep-ocean mining systems are reviewed in the aspects of manganese nodules and crusts from 8006,000-m depth. The emphasis of the investigation of hydraulic transport is placed on the shape effect of particles on the pressure gradients and flowrates. Series of tests are being conducted to study the lift characteristics of a 2-phasevertically upward hydraulic transport of 2 types of small solid particles in a PVC pipe of 1-in (2.54 cm) diameter: irregular-shaped silica sands and equivalent spherical glass beads. Pressure drops and mass as well asvolumetric flow rates were measured by electromagnetic(EM) flowmeter and mass flowmeter. The particle sizes used are 8-10 mesh. The results in turbulent flow range of 101045Re show that pressure gradients or friction factors are smaller for the spherical beads than the sands. The larger the concentration of the particles are, the larger the pressure gradients become. The larger the particle concentration is, the less the effect of particle shape on pressure gradients becomes. The shape effect is greater for the minimum particle transport velocities than for the settling velocities.

Jan 1, 1999

By Timothy C. Siegel

Given that piles are composed of different materials and installed using a variety of methods, ASTM D 1143/D 1143M-07 Standard Test Methods for Deep Foundations Under Static Axial Compression is justifiably general so that it has as many applications as reasonably possible. There are aspects of the test setup, the test procedures, and data interpretation for instrumented piles (some of which are specific to augered cast-in-place piles) that are either not discussed in detail in this ASTM standard or are not addressed at all. Specifically, the use of variable time hold times can obscure the shape of the conventional load-deflection curve, as well as, influence the interpretation of the ultimate pile capacity. Unload-reload cycles induce additional non-uniform internal axial loads within the pile which complicate interpretation of the strain gage data and increase the potential for errors. Attempts to maintain a constant top load during the hold period can lead to operational difficulties in taking measurements and are technically unnecessary. Residual load has been shown to develop in cast-in-place piles and can significantly influence the axial load distribution as interpreted from strain gage data. The stiffness of cast-in-place piles has been observed to vary with the measured strain, and a constant modulus, as provided by correlation with the unconfined compressive strength of the grout, may lead to a significantly different interpretation of the axial load distribution.

Jan 1, 2010

By Kenneth M. Maas

The Bureau of Mines inventoried the land availability for mineral exploration and development in northern Alaska and compared this land with known mineral terranes and mineral deposits, to quantify the potential for favorable location of mining claims for metalliferous mineral deposits. This report includes thirty-three 1:500,000-scale maps that depict land availability, and the accompanying text and tables relate availability acreage to areas of favorable mineral terranes. Three categories of land availability and ownership are identified, along with 12 subcategories of land status. Available land comprises approximately 14.5 million acres or 16% of the 90.3-million-acre study area; land available with restrictions accounts for 7.5 million acres or 8%; and unavailable land encompasses 68.3 million acres or 76%. Mineral terranes underlie 37.8 million acres or 42% of the study area; 5.3 million acres or 14% are available for mineral location, 2.8 million acres or 7% are available with restrictions, and 29.7 million acres or 79% are unavailable. There are 500 known mineral deposits or occurrences within the study area. This includes 271 lode deposits, of which 171 lie within a recognized mineral terrane and 55 are on available land. The remaining 229 are placer deposits.

Jan 1, 1987

By August J. Kwitowski

This report presents the results of a joint Bureau of Mines-U.S. Department of Energy project that evaluated a newly developed low-coal mining system: the 4M miniminer system. The evaluation took place from April through October 1981 and determined potential health, safety, and productivity factors for the mining system using the surface test facilities at Bruceton, PA. The planning, testing, results of testing, and a summary evaluation of the 4M miniminer system are included in the report. The miniminer system was found to be a very good concept with future potential for safe, healthful, and economic production in thin-seam mining. The mining system was also judged to have considerable potential for use in some coal seams that are presently considered unminable by other existing mining equipment. The preproduction, prototype version of the miniminer system that was tested suffered from several safety and production problems. These problems are also described, along with suggested remedies.

Jan 1, 1989

By Michael S. Contratto, Dave Marshall, Tom Brodersen

The European Union (EU) completed a new directive 2002/44/EC1 called the Physical Agents Directive (PAD) that establishes action and limit values for hand-arm and whole body vibrations. The directive specifies that: “…workers shall not be exposed above the exposure ‘limit value’.” 1 and “…once the exposure action values … are exceeded, the employer shall establish and implement a programme of technical and/or organisational measures intended to reduce to a minimum exposure to mechanical vibration and the attendant risks…” 1 The PAD limit value is effective for new machines starting July 6, 2007 and for used machines by at least July 6, 2010. These requirements apply to the users of machines, but machine manufacturers will be challenged to provide machines and information to help the users comply with the directive. Caterpillar manufactures machines with the goal of enabling our customers to comply with all regulations dealing with health and safety. Caterpillar designs all of our machines to provide a safe, comfortable and productive work environment. This study was to determine if seat suspensions could provide a reduction in the vibration environment experienced by operators of Caterpillar mid sized (<50,000KG) Track Type Tractors Methods Seat manufacturers were asked to provide seat suspensions that provide improved isolation over and above current seat suspension. Each supplier was provided with ride profiles and was asked to demonstrate the vibration reduction on a shaker table. Two suppliers provided suspensions that were compared with the current seat suspension in a field study. Three full factorial experiments were conducted. The first experiment was to evaluate overall suspension performance for four operations. The second experiment was to determine the benefit of the adjustable vertical damper at three different levels and the third experiment was to determine the effect of the fore/aft and side/side isolators. Six operators were used for the study. Acceleration was measured at the seat base and at the operator seat pad. Both the transfer function and the ISO 2631 RMS ride values were used to determine the seat suspension’s effectiveness of isolating the operator from vibration. A structured questionnaire was used to determine the operators’ subjective assessment of the seat suspensions. Results There was significant operator-to-operator variability in the vertical direction (>35%), however there was little variability in the fore/aft and side/side direction based on seat base

Jan 6, 2006

By Charles Vaught, Jeff Duncan, Michael J. Brnich, Lisa J. Steiner

This document contains most of the materials needed to use the exercise. The main part of the document is the instructor&apos;s copy. It tells how to use the exercise, presents the objectives, the master answer sheet, the scoring key, and discussion notes to be used following the exercise. The next section summarizes results from field tests of the exercise, and reports the miners&apos; evaluation of the activity. The last part of this document is three appendices. Appendix A is the exercise problem booklet. This booklet can be duplicated locally. The booklets are reusable. One is needed for every person in the classroom. Appendix B is the answer sheet. Copies of this answer sheet must have the latent image (invisible) ink answers that appear in Appendix C printed on them.3 Answer sheets are consumable. One is needed for each person or each small group of persons who work the exercise. Exercise Summary Read this section first. It determines if the exercise is appropriate for your classes. If you choose to use the exercise, examine the table of contents and review the remainder of this document. Type: Latent image Audience: Remote control and extended cut miner operators and face crews Length: Eight questions (30 minutes for administration plus 30 for discussion) Skills: Remote control mining procedures including remote control mining, taking extended cuts, resetting breaker on mining machine, and setting timbers. Communicating mine conditions, influencing safe behaviors when mine conditions are less than stable Location: Underground coal mine, four section continuous mining operation Average seam height is 48 inches Problem: Your regular job is on the general labor crew at Cripple Creek #9 mine, a four section continuous mining operation. The mains are 9 entries wide and panels are 5 entries across. You and the rest of the crew had annual refresher training about 3 months ago. For the past few days you have been sent to 2 South panel to fill in as the third shuttle car operator. This morning, however, your buggy is down. The face boss asks you to get the scoop and take seven or eight timbers to the number 5 entry because the last shift got off sight line. The miner will be working in entry 5 while the bolter crew pins entry 4. When you get up to the face you see that Mo, the remote control continuous miner operator, has rounded off the left inby corner in order to make his first cuts in the right hand rib. Now, he has squared around enough so that you and Red, the miner helper, can set some posts on the corner. The two of you set posts along the left inby rib of #5 entry while the shuttle car operator waits. You are in a tight spot when Mo decides to start mining. You must decide where the best place is to stand for safety and to be out of the way.

Jan 10, 1999

By Leonard Obert

THE CRACKING AND POPPING of rock, often heard by men working underground, for years has been interpreted as a warning of danger and unstable ground. However, not until 1939 was it discovered that rock under stress generates subaudible and sometimes audible seismic disturbances (referred to as "micro-seismims" 4), which can be detected with the use of a suitable seismic apparatus. Since that date laboratory and field investigations have been in progress to ascertain to what extent this phenomenon can be utilized to detect, localize, and determine the magnitude of areas of instability in and around mine openings and to predict if and when failure will occur. These investigations have included a determination of the types of problems to which the method is applicable and the effect of rock type, geological defects, such as joints, fractures, faults, and other uncontrollable factors, on the reliability of results. Six reports have been prepared covering the investigations conducted between 1940 and 1952 (4-9). 5 These reports describe some of the characteristics of micro-seismims, as determined from both laboratory and field tests; the equipment used to pick up and record micro-seismims; the general test procedure and method of analyzing results; and applications of the method to specific mining problems.

Jan 1, 1957

By J. L. Kearns

The importance of optimizing equipment replacement decisions becomes more critical each year due to the rising costs of buying new equipment versus maintaining old equipment. Replacing equipment when it is physically worn out, or replacing it too soon or too late relative to its Economic Life (when it is economically worn out), is very costly. After extensive literature review and research, Kennecott has developed its Equipment Replacement Guide (ERG) system which identifies, evaluates, and justifies the replacement of uneconomical equipment. The system considers such critical factors as inflation, decreasing work capability, increasing maintenance/repair and operating costs, taxes, time value of money, return on investment, salvage value, and investment tax credit. These factors are used in a system of equations which balance the costs of new equipment against the total operating costs of old equipment. The solution of the equations determines the Economic Life of equipment. Replacement of equipment at the determined Economic Life will earn the specified, required return on investment that is used in the calculation of the Economic Life.

Jan 1, 1979

By E. J. Lintner

This paper is one of a series being prepared by the Bureau of Mines describing; gypsum mining and crushing methods and costs at various operations throughout the, United States. These papers are designed to dissemminate technical information regarding methods used. The cost tabulations represent local operating expenditures only and not total production costs. It is recognized that publication of total production costs may in many instances cause embarrassment to the individual operator as well as to the industry as a whole; on the other hand, operating costs are essential to the technical discussion and. study of the methods employed. The attention of the reader is specifically called to this differentiation in order that no misunderstanding of the scope of the cost tabulation shall ensue. The following report deals specifically with the mining and primary crushing methods employed at the plant of the Ebsary Gypsum Co., Inc., Wheatland, Monroe County, N. Y. This company is capable of maintaining a maximum yearly production of 220,000 tons of crushed gypsum, thereby ranking as one of the largest gypsum operators of the State. The methods and practices employed typify the standard methods followed by gypsum producers in western Now York State, The bed of gypsum mined lies only 35 feet beneath the surface and is above average thickness for this vicinity.

Jan 1, 1937

By M. E. Gershon

I would like to congratulate Professor Gershon on an idea that is obviously valuable and is certainly new to me. It has, however, to be further developed, in that one can get fallacious results by limiting oneself to positional weights. In the example problem, the positional weight of one block was 8.6 (the 8.0 value in the paper was incorrect) for 36 units in the cone, for a mean block value of 0.239. The positional weight of the second block was 4.4 for 15 units, for a mean block value of 0.293. Surely one would expect the second block to be rated higher. Additionally, the time value of money adjustment cannot be determined by depth, because the time that a block is mined is determined by the mining sequence, not depth. Figure 1 shows a slightly altered version of Professor Gershon’s pit. The overall value of the pit is the same, as are the total values under each of his blocks. The values in the right-hand cone have been reversed top to bottom, and the values in the rest of the pit adjusted to keep the central cone total unchanged. All values have been multiplied by 10. Figure 2 shows the sequence of mining, at three blocks per year, for Professor Gershon’s pit, and Fig. 3, the sequence for a pit under the other block. Table 1 shows the value and discounted value (157. ) of Professor Gershon’s pit, and Table 2 shows similar values for the second pit. It is apparent that the second pit schedule is more valuable than the first.

Jan 12, 1987