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By B. Asbury, M. Cigla, C. Balci

The Western Mining Resource Center (WMRC) at the Colorado School of Mines (CSM) received a grant from the National Institute for Occupational Safety and Health (NIOSH) to perform a study that will help reduce the amount of respirable dust generated from the cutting of coal. The study is based upon laboratory testing and field experience. This information is being used to develop a new cutterhead design in conjunction with Joy Mining Machinery. The new cutterhead design is being evaluated with existing computer models developed at CSM. The new continuous miner cutterhead will be tested at the Twenty Mile Coal Company’s Foidal Creek Mine. Baseline testing with the current cutterhead will also be performed. This paper presents laboratory test results, design methodology, and test results performed to date.

Jan 1, 2002

By Mohammed Sakr

The use of helical piles as a deep foundation option has considerably increased in the recent years to support a variety of loads, from small loads for several applications such as residential housing, solar farms, utilities and retrofit projects, to large loads for many applications such as commercial, power transmission lines, oil facilities and industrial applications. Therefore, it is necessary to qualify and quantify their axial capacities and performance characteristics. This paper presents the first full-scale axial compression and tension (uplift) testing program executed on large capacity helical piles installed in cohesionless soils. A total of eleven pile load tests using either single or double-helix piles with shaft diameters that varied between 324 mm to 508 mm (12¾ in to 20 in) were carried out, including seven axial compression tests and four tension (uplift) tests. The results of the axial compressive and tensile pile load tests as well as field monitoring data of helical piles installed in dense sand are presented in this paper. Based on the results of this study it was found that helical piles have developed significant resistance to axial compressive loads up to about 2920 kN (656 kips) and tensile loads up to 2900 kN (652 kips).

Jan 1, 2011

Prominent among the ore minerals at Mt. Ellison, in the Brock's Creek district, Northern Territory, are a number of copper-bismuth sulphides wittichenite, aikinite, emplectite, in association with nativebismuth, chalcopyrite, bornite, chalcocite, sphalerite and linnaeite.Linnaeite and aikinite formed first and were followed by native bismuth. Wittichenite was later and substantially replaces earlier minerals. Replacement of aikinite by wittichenite has produced secondaryor reaction bismuth.INTRODUCTIONThe Brock's Creek district of the Northern Territory lies to the south east of Darwin and has been the locale of intermittent mining of small but rich deposits of diverse ore type. Gold, tin, and copper ores were recovered especially between 1890 and 1910 with minor exploitation up to the present time. Copper ores were of prior importance, the main production coming from supergene enriched deposits of chalcocite.The mines are situated in strongly folded Precambrian strata comprising slates, sandstones, volcanics and amphibolites with replaced haematitic rocks (Sullivan, 1953). The strata in the Brock's Creek area immediately north of the Darwin-Birdum railway line are domed around a roughly circular granitic mass some 5 miles in diameter. The Mount Ellison mine is located near the N.E. margin of the granite in metamorphosed basic country rock.Study of a series of polished sections from Mt. Ellison revealed the presence of linnaeite, chalcopyrite, bornite, aikinite, wittichenite, emplectite, bismuth, sphalerite, and chalcocite. With the exception of sphalerite and emplectite each of these minerals is prominently developed and intimately intergrown with the other constituents.

Jan 1, 1963

By B. G. Tarasov

This paper proposes the further development of a recently identified shear rupture mechanism (fan mechanism) that elucidates a paradoxical feature of hard rocks ? the possibility of shear rupture propagation through a highly confined intact rock mass at shear stresses that can be significantly less than frictional strength. In the fan mechanism, failure is associated with consecutive creation of small slabs (known as ?domino blocks?) from the intact rock in the rupture tip, driven by a fan-shaped domino structure representing the rupture head. The fan head combines such unique features as extremely low shear resistance, self-sustaining stress intensification, and self-unbalancing conditions. Consequently, the failure process caused by the mechanism is inevitably spontaneous and violent. Physical and mathematical models explain unique and paradoxical features of the mechanism, which can be generated in primary ruptures and segmented faults. The fan mechanism provides a novel point of view for understanding the nature of spontaneous failure processes, including shear rupture rockbursts. The process explains, in particular, features of shear rupture rockbursts such as activation at great depths, generation of new shear ruptures in intact rock mass, nucleation of hypocentres at significant distances from the excavation, shear rupture development at low shear stresses, and abnormal rupture violence.

Jan 1, 2014

By Tracy Brettmann

The use of rock-socketed Augered Cast-In-Place (ACIP) piles is new to the Austin and central Texas region. This case history describes the design methodology, load test results, quality control procedures and the rate of production pile installation for the first large commercial project where ACIP piles were used in Austin. The piles were 24 inches in diameter and extended through about 45 ft of alluvial materials to be socketed 6 ft into limestone. A full-scale instrumented load test was performed on a test pile that was loaded to 452 tons and held for 24 hours. Telltales were installed in the middle and the tip of the test pile. As part of the overall quality control procedures, singlehole sonic integrity logging was performed on the production piles to verify structural integrity during pile installation. During pile production, an average of 14 piles per day were installed, which is approximately seven times faster than the original design that consisted of drilled shaft foundations.

Jan 1, 1998

By W. Mbhalati

"Conzal Mine was not meeting production targets in 2013, and it was established that this was caused by the inability of the load haul dump machines (LHDs) to tram the required tonnages. An investigation of the LHD productivity was therefore conducted to identify the inhibiting factors. This was accomplished by carrying out a literature review on LHD operations to gain in-depth knowledge and conducting observations in the working environment. The relevant information and data on the LHD type used at Conzal was also acquired.The major inhibitor was found to be excessively long tramming distances in all the sections of the mine. The one-way tramming distances were all significantly greater than the 90 m set in the mine’s code of practice (COP), with the Main Shafts section having the longest average one-way tramming distance of 260 m. The other inhibitor was LHD utilization, which in 2013 was only 47% against a target of 70%. Simulation of the LHD operation, taking these two factors into account, showed that production could be increased by more than 100%. As a result, it was recommended that conveyor belts should be extended regularly in order to keep tramming distances within the recommended one-way distance of 90 m. In addition, utilization can be improved by minimizing employee absenteeism as well as by modifying the travelling routes such that LHDs do not encounter unnecessary delays.Paper written on project work carried out in partial fulfilment of BSc. (Mining Engineering)"

Jan 1, 2015

By S. H. Jason Choi

The Systems Conveyance and Operations Program (SCOP) is being implemented to convey tertiary-treated effluent to Lake Mead near Las Vegas, Nevada. The Reach 3 Tunnel Project is part of SCOP. The tunnel?s planned location along and across the Las Vegas Wash creates challenging tunneling conditions. A number of feasible excavation and initial support methods are being considered during the final design stage. This paper describes how the tunnel construction options were refined based on anticipated tunneling conditions and compatibility between tunnel excavation and initial support methods. A brief description of the most significant characteristics of the anticipated ground conditions is included for the purpose of discussion.

By Anthony J. Konya

"This paper was written during part of the author’s student co-op with Cargill Salt at its Avery Islandunderground salt mine in Louisiana. Blasting salt is a unique type of blasting that is different than blasting other rock types. The plastic nature of salt, along with its large swell factor make salt a challenge to blast. The Cargill salt mines use and have tested a variety of different methods for breaking salt in an efficient manner, however these blasting methods are rarely used in other operations nor talked about today."

Jan 1, 2016

An active list of permissible explosives was published in December 1936 as part of Bureau of Mines Report of Investigations 3324, under the title "Active List of Permissible Explosives and Blasting Devices Approved Prior to July 31, 1,936." This list included 170 brand names. Changes in the list that have been authorized to June 30, 1937 placed 35 additional brands of permissible explosives on the active permissible list as a result of tests, changes in brand names, or transfer from the inactive list. Ten permissible explosives were transferred from the active to the inactive list. The present list contains 196 brand names, one explosive having been placed on the list subsequent to June 30, 1937. The brand names of the permissible explosives placed on the active list are as follows: [ ]

Jan 1, 1937

By H. L. Anthony, A. C. Richardson, G. D. Coe

"INTRODUCTION The Warrior View mine of the Seaboard Coal Corporation is located in Tuscaloosa County on the Warrior River about 14 miles northeast of Tuscaloosa, Ala. The Brookwood bed at this point yields a coal with fair coking qualities, and the product from neighboring mines on this bed has been used for the manufacture of blast furnace coke. The output of the Warrior View mine, however, is used exclusively for domestic and steam-raising purposes.This paper continues the series° of reports on the washability of Alabama coals which are based upon the study of coal preparation in Alabama now being conducted by the U. S. Bureau of Mines and the University of Alabama with the cooperation of the different coal mining companies. This paper contains screen-sizing and float-and-sink tests of a representative sample of run-of-mine coal, and flakiness and crushing tests on certain sizes.Published information on the Brookwood bed is very meager. Fieldner6 gives the proximate and ultimate analyses for a number of seam samples taken from representative mines working this bed. Gandrud and Britton7 show sections of this bed taken at Searles, Ala. They also give the specific gravities of the coal, the bone, and the shale partings.Table 1 give the proximate and ultimate analyses for the 3/4 to 3/16 inch size of raw coal. Table 2 gives the sulphur content and the ash fusibility temperatures of the float-and-sink fractions for this same size. The character of the coal is very uniform throughout the range of sizes produced and, as it was not convenient to have these analyses on all sizes, this size was chosen as being representative of the coal. From the information available it is evident that the coal preparation problem is restricted to one of ash reduction.SAMPLING AT THE MINEAt the Warrior View mine the run-of-mine coal is dumped from the mine cars upon a 3-inch grizzly. The oversize is crushed in rolls set at 24 inches and joins the undersize before being elevated to the raw-coal bin ahead of the jig. The sample was caught at the point where elevates discharges into the raw-coal bin, by taking a proportional amount of the coal at 10-minute intervals over the period of a day's run, The total sample amounting to 2.7 tons was shipped to the laboratory at Tuscaloosa for the washability studies."

May 1, 1932

By R H. Sillitoe

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Geological concepts are employed routinely in porphyry copper exploration at the area selection, prospect appraisal and deposit definition stages. Regional, district-scale, deposit-scale and laboratory-based concepts can all play a role, with the resulting porphyry copper models providing templates for the integration of geochemical and geophysical responses and interpretations. Of the 19 concepts and parameters selected for brief discussion, those relating to subdivision of porphyry intrusions, understanding of diverse and commonly complex alteration-mineralisation patterns and lithocap characterisation are undoubtedly the most influential in exploration. Several of them are of particular importance because of their role in promoting grade development. Additional belt-, district- and deposit-scale features are currently little used but hold promise, whereas others have less practical value but help in underpinning the evolving porphyry copper genetic model.CITATION:Sillitoe, R H, 2015. Recent advances in porphyry copper geology and their exploration utility , in Proceedings PACRIM 2015 Congress, pp 35–44 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By David Smith, Bernie Martin

The Queens Bored Tunnels consist of 11,000 feet of 19'-6" inside diameter tunnels mined through rock, mixed face and dense glacial till, constructed with bolted gasketed one pass reinforced concrete liner. The tunnels are to be excavated with a pressurized face TBM, either EPB or slurry. The construction of the tunnels will require ground stabilization in the mixed face area, instrumentation and monitoring of railway infrastructure, underpinning of bridges, relocation and protection of utilities, demolition of some industrial buildings, construction of open-cut approach tunnels and emergency exits and vent plants. The purpose of this paper is to describe the scope of work, the suggested methodology and the proposed construction schedule.

Jan 1, 2005

By C Adams

Reports of delays and cost blowouts in major study and construction projects are becoming increasingly prevalent in the resources industry. This is mainly being attributed to an escalating cost environment associated with the increased number of projects in the development to construction pipeline and a scarcity of competent skilled resources to deliver these projects. However, not all this effect can be directly attributed to the current environment. Historically the mining industry has not performed well in its ability to deliver projects according to the financial and physical parameters forecast in the feasibility study process. To manage the risks associated with delivery of major projects, resource companies need to ensure they use a standardised approach to management of their project development to satisfy project objectives and enable more efficient use of the increasingly limited available resources. Each discrete step in advancing the project from scoping study to operations needs to be integrated, reducing the amount of rework and duplication. This paper is primarily a consolidation of existing ideas on project management systems but also introduces new concepts to solve current issues. It describes the basic components of a typical mining project, the issues that commonly arise, the key attributes, and critical steps required for an effective integrated project management system covering projects from initial scoping studies through to project commissioning and operation. This paper focuses on technical study components of the mine development project with allowance for transitioning to design and construction and operation phases.

Jan 1, 2006

By Robert L. Frantz

The performances of the three bituminous coal demonstration methane re¬covery boreholes, located in Greene County, Pennsylvania, are reviewed. Development of these vertical holes was largely underwritten by project funds. Reference is also made to an anthracite coal methane project in Luzerne County, Pennsylvania. This involved one vertical hole and was underwritten by a utility company. In addition, an exploratory drilling in the southern anthracite, which provided the project group with coal cores for methane gas analysis, is also cited. The technical and economical data that were gathered from the various methane projects are analyzed. Finally, the advantages and disadvantages of methane recovery by vertical boreholes are assessed.

Jan 1, 1978

By F Farías, D Villa

Codelco’s Salvador Project has been operating a block/panel caving mine for more than 50 years. This underground mining method dynamically mixes the ore and dilution. As a result, forecasting grades is difficult and achieving 100 per cent extraction of the reserves is practically impossible. A substantial volume of the ore mixed with dilution becomes remnant ore and remains to be subsequently extracted.A potential open pit mine is under evaluation at Codelco’s Salvador Project, which includes the extraction of remnant ore post-block caving extraction. An effective methodology has been implemented to estimate what is left behind once the underground mine has closed. A new mixing method using the Cellular Automata (Alfaro and Saavedra, 2004) approach has been used to allow estimation of the remnant ore with a sufficient level of confidence to be included as part of the open pit reserve.A remnant block model is created using elements such as in situ block model, drawpoint layouts, historical production records and the drawpoint extraction. Using this information, simulations of the extraction of the mine by month from 1959 to 2019 were completed, using different mixing scenarios and trying to replicate the tonnage and grade extracted.Finally, the remnant block model is categorised using a score card with four inputs to assess the risk of the estimation of this material into a category class (measured, indicated and inferred).CITATION:Villa, D and Farías, F, 2016. Remnant ore model generation and categorisation post-block caving extraction at Salvador Mine, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 461–470 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By Paul Meadows

This Bureau of Mines report presents operating practices and results of pressure maintenance and secondary recovery by water injection or by water injection supplemented by gas injection. Particular emphasis is placed on the results of water injection, which is the principal oil-recovery method employed in projects covered by this report. No attempt is made to study gas-injection projects or operations that are considered water-disposal projects. Also, this report does not include water-injection projects that have not been in operation long enough to evaluate results. Figure 1 is a map of north Louisiana showing the geographical locations of the projects included in this report. Most of the data used in this study were supplied by unit operators, operating companies, and the Louisiana Department of Conservation. Reservoir information and recovery data are generally those supplied by the operators, but include revisions where deemed necessary.

Jan 1, 1962

By Ellis S. Hertzog, James R. Cudworth

Tremendous interest has been evidenced in the subject of dewatering and drying ooal for the past 10 years, and yet little effort has been made to summarize the literature, at least so far as this country is concerned. Only a few published articles have dealt solely with dewatering and drying coal. In most cases the subject has been discussed briefly, either in general terms or as to specific installations. It is desirable that a compendium be prepared collecting in one place information on the dewatering and drying of coal, the needs for this process in various fields, the available equipment, and the current American practice in regard to it. This work was underta..lten by the :Bureau of Mines in cooperation with the University of Alabama. New coal-washing plants in which various types of dewatering and drying equipment were in operation were visited in-Pennsylvania; Ohio, India...~a~ and Illinois. The dewatering·and drying of coel has .been studied in this coimtry by the Surface Preparation ·Committee of the ·coal Operato~s• Committee of the .American Mining ·Oongress. In GermaIJY .it has received the special attention of the Reichskohlenr·at, and in Great Britain of the Utilization of Fuel Commi-t-tee of the Insti ti.ite of Min"ing Engineers.

Apr 1, 1938

By Alexander Siefert, Steffen Pankoke

In the development of commercial vehicles as well as of passenger cars, the effects of vehicle vibrations on operating safety, health and comfort can only be predicted by numerical simulation when appropriate occupant models are available. Such models must be based on human anatomy and have dynamic properties of real humans in order to achieve realistic results. Since human dynamic behavior depend on posture and percentile, the occupant model needs to be adjustable to these parameters with respect to geometry and dynamic properties [1,2]. Dynamic Human Finite-Element-Model CASIMIR CASIMIR is a non-linear, dynamic finite-element-model of the human body. It consists of a dynamic model of the upper torso with head, neck, shoulders and arms as well as of a dynamic model of the lower extremity with pelvis and legs. The most important part is the lumbar area with dynamic non-linear models of the lumbar spine and of back and abdominal musculature. The frequency-dependent characteristics of the intervertebral discs and the effects of muscle activation and non-linear frequency-dependent muscle properties are included. In the latest stage of development, CASIMIR has been equipped with a compliant model of the body surface in the contact areas to the seat. This results in a very realistic transmission of static and vibrational forces into the human body, see fig. 1. Intense model verification and validation has been performed in all stages of model development, starting with validation of small components like intervertebral disc, ending with validation of whole-body-vibrations using measurements of the dynamic mass / mechanical impedance [4]. For an in-detail examination of stresses in the vertebral bodies and discs, a non-linear submodel of the lumbar spine with an increased number of degrees of freedom can be coupled to the whole-body-model, enabling the researcher to examine local effects of vibrations and single shocks on the lumbar materials. [ ] Since it is well known that human dynamic behavior is significantly affected by anthropometric data and posture, CASIMIR can be individualized to the anthropometric status of single individuals or to the mean values for specific percentile groups. Furthermore, posture can be adjusted to the seating conditions applicable to a specific vehicle. Posture modification capabilities include the variation of the lumbar lordosis [3].

Jan 6, 2006

By Jörg Fischer-Bühner

Conventional 22ct Au jewellery alloys are comparably soft in the as-cast and soft-annealed state and hardening by cold-working is the only way of giving strength to the jewellery. The paper first focuses on hardening of 22ct jewellery alloys by conventional means, i.e. solid solution hardening with base metals (aiming particularly at an increased as-cast hardness) as well as precipitation hardening by alloying with base metals beyond the solubility limits and subsequent age-hardening heat treatment. Co-additions of ~2% turned out to result in most pronounced solid solution hardening up to ~100 HV1 in an investment cast & quenched state. Subsequent heat treatments, consisting of solution annealing at 850°C for 1h followed by water quenching and ageing at 300°C ? 400°C for ~ 1h lead to pronounced age-hardening with a peak hardness of ~ 260 HV1. In contrast, 22ct Au alloyed with Ni, Fe or Sb display no age-hardening effect within the same range of heat treatment parameters. The 2nd part of the paper reports on some preliminary trials to enhance the hardening effect of the base metals by additions of suitable elements, which possess a strong tendency to phase formation with the added base metal during ageing treatments. It is shown, that the age-hardening behavior of 22ct and 990/995 Au alloyed with Co or Ni can be remarkably influenced by additions of Sb. A total of only 10wt%0 of CoSb or NiSb-additions lead to a peak hardness of ~ 150 HV1 for a 22ct Au and ~ 100-120 HV1 for 990 Au , which is obtained already after very short ageing times (20-40min) at 300-400°C after solution annealing at 700°C / 1h / water quenching. It is suggested that the age-hardening mechanism in these alloys consists in precipitation of intermetallic CoSb- and NiSb-phases.

Oct 1, 2003

By G. Papachristodoulou, O. Trass

"Performance data for both wet and dry grinding of materials have been obtained in this novel, planetary ring-roller mill over wide ranges or operating conditions. The Szego mill consists of a stationary cylindrical shell inside which grooved, radially mobile rollers rotate, driven by a central shaft. The mill has several internal design variables such as number, diameter and length of rollers as well as size, shape and pitch oi helical grooves. It is compact, has a high specific capacity, modest power consumption, and can grind many materials down to ultrafine powders. Illustrative data on product fineness and mill power consumption are given along with results from studies on grinding kinetics.INTRODUCTIONThe extensive use and importance of grinding as a unit operation, coupled with the rather low energy efficiency of conventional equipment provide a challenging incentive to investigate novel methods of comminution. Yet, most current development work is taking place in mill performance modelling and optimization, or with various detailed improvements rather than in the field of new equipment development.This paper is a report on the development of a ring-roller mill invented by the late L.L. Szego which embodies several novel concepts. The mill has a broad range of applications, may be operated wet or dry, and can grind materials down to ultrafine sizes with modest energy consumption. It has been developed by General Comminution Inc. in close cooperation with the University of Toronto."

Jan 1, 1986