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By Wilson Blake

This report presents the results of a 7-year Bureau of Mines program to review, revise, and make an effective engineering tool of the microseismic method of determining the stability of rock structures. The program consisted of developing new microseismic equipment and data analysis techniques and extensive field investigations to demonstrate the effectiveness and potential of the broad-band microseismic method. The guidelines for choosing the components of a microseismic system are presented along with approximate cost figures. Different microseismic systems are discussed, including completely automated systems. Procedures for conducting microseismic investigations and analyzing microseismic data are discussed in detail. Field situations which show the full value of the microseismic technique as an engineering tool are described.

Jan 1, 1974

By Wayne J. Nordstrom, Dennis L. Murr, James E. Wennen

National Steel Pellet Company (NSPC) conducted pilot scale testing and computer simulation studies which indicates that the capacity of the secondary grinding mill could be increased and that concentrate grade improvement could be expected with improved classification in the grinding circuit. Based on these studies, a decision was made to modify one secondary ball mill line at NSPC to include both cyclone and screen classification with magnetic separation applied to the circulating load. This paper will briefly discuss the studies leading to the decision to modify the circuit, the design of the modified circuit and the initial start-up and operating experience.

Jan 1, 1997

By Nader Golchinfar

The V-shaped breakout zones around excavation boundary have been captured by a variety of numerical methods such as FEM and DEM methods and failure criteria such as linear Mohr-Coulomb and non-linear Hoek-Brown failure criteria. Diederichs (2007) used Hoek-Brown parameters in his spalling parameter approach; however, it is convenient to use the Mohr-Coulomb failure criterion in numerical modeling because the material parameters can easily be determined from triaxial tests. It is shown in this study that when peak and residual strength parameters as well as dilation angle are properly defined, the brittle Mohr-Coulomb failure criterion can be used to model depth of failure near underground excavations satisfactorily.

Jun 1, 2012

By Moatassem Abdallah

Buildings in the United States account for 72% of electricity consumption, 40% of energy consumption, 13% of water consumption, 39% of carbon footprint, and 30% of waste output. In order to minimize these negative environmental impacts, many public and private owners are requesting that their buildings be more sustainable and certified under the widely known programs such as leadership in energy and environmental design for existing buildings (LEED-EB). To accomplish this, buildings are increasingly integrating green building measures including energy efficient lighting, motion sensors, thermal pane glass, geothermal heat pumps, EnergyStar rated HVAC systems, photovoltaic systems, and wind turbines. This research paper presents the development of an automated decision support system (DSS) that is designed to optimize the selection of green building measures which can be used to upgrade existing buildings. The developed DSS incorporates two optimization models that are capable of (i) minimizing the total upgrade costs required to accomplish a specified LEED-EB certification level such as silver or gold; and (ii) maximizing the number of accredited LEED-EB points within a specified budget of upgrade costs. The DSS is designed to identify a set of optimal upgrade decisions that accomplishes these two optimization objectives. An application example is used to illustrate the capabilities of the DSS and to validate its result.

Aug 1, 2013

By AIME AIME

FOUR separate groups of conveyors are installed in the Morenci Reduction Works as follows: (1) Ore-handling conveyors from the primary crushing plant to the coarse ore bin, from the coarse-ore bin to the secondary crushing plant, and from the secondary crushing plant to the ore bin in the concentrator plant. (2) Conveyors in the mill section of the concentrator plant. (3) Conveyors handling concentrate from the filter plant to the bedding plant, and from this plant to the smelter. (4) Conveyors handling flux and custom ore in the smelter crushing plant and to the bin at the bedding plant.

Jan 1, 1942

By J Bean

Iluka Resources Ltd developed the Jacinth-Ambrosia Mine (Jacinth) in the Eucla Basin during 2009 and 2010. In this arid climate the operation relies on hyper-saline groundwater from a palaeochannel for process and potable water supplies. The water is hyper-saline, acidic and mildly reducing, with high ferrous iron concentrations. Ferrolysis commences on exposure of water to oxygen, resulting in increased acidity and the conversion of dissolved ferrous iron to insoluble ferrihydrite. The unstable groundwater forces a careful balance between interventions relating to maintaining pipeline efficiency, corrosion protection and processing aspects. Providing an oxidising environment at the head of the pipeline will result in the precipitation of akaganenite and goethite in the pipeline, which over time reduces pipeline efficiency. However, sending too much ferrous iron forward may reduce processing performance.The processing plant experiences changes in water chemistry in response to the variability of iron concentrations and pH within the pipeline, and the spatial and chemical variability of ore. As the main orebody at Jacinth contains little buffering capacity a source of carbonate in the overburden is carefully used to allow the cost-effective control of process water pH.This paper highlights the importance of understanding the chemistry of saline make-up water, ore, and overburden when designing water treatment facilities and heavy mineral processing facilities.

Oct 5, 2011

By Jason Herron, Joseph Brown

The common couplings for joining sections of helical piles with an outside diameter of 6.625 inches and 8.625 inches are square on square, flange to flange, external pipe sleeve, internal pipe sleeve, and welded joint. Each coupling type has advantages and disadvantages in efficiency, capacity, installation, and economics of the installed pile. All these coupling types have been used in the helical pile market in North America for various applications and designs. Many of these applications require on-site testing, but test records are not typically shared with the helical pile industry. Due to the lack of information available for square on square and flange to flange couplings, testing was done to compare the efficiency of installation, load to deflection response, and torque to capacity ratios of external pipe sleeve, square on square, and flange to flange couplings. Field installations and tension tests were performed in non-cohesive (sand type) soil near Caseyville, IL and in cohesive (clay type) soil in Centralia, MO. The data collected during these tests included rotations per foot during installation, installation torque, applied pressure, and deflection. The results of this testing are analyzed and discussed within this paper. The results indicate that the square to square coupling is the most efficient of the designs tested, but this conclusion cannot be fully justified without further testing due to the variability in the data gathered and the small number of piles tested. INTRODUCTION A helical pile is typically assumed to be a medium-displacement pile when its outside diameter is between 4.5 inches and 8 inches and a high-displacement pile when its outside diameter is greater than 8 inches. A helical pile designer has multiple options when selecting a coupling type for medium- to high-displacement helical piles. Each type of coupling has advantages and disadvantages and must be analyzed on the bases of efficiency, capacity, installation, and economics of a project. Typical couplings that are chosen by designers include square on square, flange to flange, external pipe sleeve, internal pipe sleeve, and welded joint. A helical pile must transfer axial, lateral, bending moment, and torsional loads, and the coupling must be designed to effectively and efficiently transfer each type of load. During the installation of a helical pile, the rate of penetration and the disturbance of soil layers play a critical role in the efficiency and torque to capacity ratio (Kt) of the pile. It is common for a coupling to protrude beyond the outside diameter of the pipe section being used. This is necessary for the function of certain coupling types and can facilitate the connection of couplings. However, it causes increased soil disturbance and reduce the rate of penetration due to soil bearing against the protruding portion of the coupling. A helical pile designer typically will work to minimize the coupling protrusion and create a pile with optimal installation efficiency but may choose a design with lower installation efficiency if it offers sufficient economic advantage.

Jan 1, 2019

By Richard Campbell, Claire Pirona, MEHMET KIZIL, Ismet Canbulat, Stephen Giese, Ravindu Goonawardene, Edward Steed, Serkan Saydam

The Australian longwall mining industry spends millions of dollars per year on proactive and reactive ground consolidation applications across most of the operations currently in production. The design and effectiveness of the applications and products vary widely and are based predominantly on-site precedence or what were considered successful applications at other sites in similar situations. In the continual improve the effectiveness of how consolidation products are used and when by enhancing our knowledge of the mechanical properties of products used in underground coal applications and applying this increased understanding to geotechnical design. One of the current challenges to further developing more appropriate and accurate geotechnical design methods for consolidation activities is the lack of standardised materials testing and knowledge of rock mechanics data on in situ performance. The lack of industry standardisadesign of consolidation programs, with a reliance on experience-based guidance for rockmass consolidation design. consolidation products. The program was designed to provide the industry with a set of geomechanical property index tests and a data set that can be utilised by rock mechanics engineers as baseline information for product evaluation and engineering design. The laboratory work undertaken is critical to understanding the exact small-scale mechanical properties of these products and testing was carried out at Monash University for various states of curing of each product. Recognising that the speed at which a mixed product develops its desired properties to act as a support element in underground coal mines is critical to its serviceability. This paper presents the testing rationale proposed, the testing results, and a framework for how the data set can be used to improve the engineering basis for ground consolidation design, in terms of expected rockmass performance under various mining conditions and application parameters.

Jun 25, 2024

By A. C. Watts

For several years, a mine in Colorado experienced considerable trouble from small fires caused by the blasting of coal. Although a well-known make of permissible powder was used, it was first thought that the powder ignited gas that might be present and that this, in turn, set fire to line brattices or to the coal. Experiments were, therefore, conducted with another make of powder, but the results convinced the superintendent of the mine, Robt. Williams, Jr., that the fires were not caused by the powder but by the high-voltage electric current used for detonating the shots. The mine "makes" gas very freely, giving off from three-fourths to one million cubic feet of methane every 24 hours. The coal is a good grade bituminous of a very free burning quality. Electric shot-firing from the outside, after all men and animals were outside, had been practiced for a number of years. The shooting circuit was connected with the main power circuit at the mouth of each entry. Shooting circuit switches were mounted in boxes, which were kept locked with the handle of the switch, in open position, showing through the bottom of the box. The door of the box could not be shut and locked when the shooting switch was closed. At the entrance to each room, or working place, a small switch, called the miner's switch, was placed on the shooting line. It was the duty of the miner, when entering his place at the beginning of the shift, to see that this switch was open and that it was kept open until he left the placc at the end of the shift to go out of the mine. Grounded return was used for main power lines. The current was 500 volts, direct current, with 100 to 300 amp. The nearest working face was 9600 ft, from the shot-firers' switch outside the mine and the most remote working face was 2½ miles. The various working faces were scattered over a wide area between these two points. A description of the main power line would be valueless; the conductors were of sufficient size, the drop in voltage being not more than

Jan 1, 1927

By Michel Guillot

Gaz metal arc welding is commonly used for producing large frames and assemblies. Even for light aluminum and thin wall assemblies, the GMAW technique is increasingly preferred over the GTAW technique. This is particularly true where the welding gun motion is achieved accurately with automated or robotic systems and when using pulsed or regulated metal deposition. In this study, butt joints in floor welding position are tested at speed ranging from 1.5 to 16 m/min. Attempts are made of find parameters providing good and repeatable joint quality with minimal distortion and good appearance even at high travelling speeds. Taguchi experimental plans are proposed with different parameters tested with sheet metal samples. The parameters include typical GMAW machine settings, joint preparation geometries, wire gages, gun angles, wire feeds, and more. The robot motion speed and the proximity of the part are also considered. Direct monitoring of machine welding current and voltage is achieved. Once is found the best set of parameter settings, additional tests are carried out to verify the repeatability of weld quality. Secondly, these conditions are applied for joining and testing a floor panel made of several extrusions. Weld quality is established with Vickers micro-hardness measurements, cross section geometries of the weld pool including penetration, tensile tests and metallographic observations to establish the amount of porosity and weld microstructure in the HAZ.

Jan 1, 2011

By D. G. Kotlyar

Oxidized sulfide minerals, commonly formed by weathering, increasingly are becoming important resources as primary sulfide deposits are depleted. Oxidation, in general, reduces selectivity and recovery in flotation. The objective of this research was to determine the mechanisms of oxidation and collector adsorption in sulfide systems as a step towards developing improved technologies for beneficiation of oxidized sulfides. Data from microcell flotation tests are combined with electrochemical and spectrophotometric measurements. The adsorption of ethyl xanthate (EX) on oxidized sulfides was characterized using AC impedance techniques and correlated to flotation response. The floatability of chalcocite, chalcopyrite and pyrite was dependent on the extent of oxidation. Oxidation for 1?) d at 65? C inhibited flotation of chalcocite, and chalcopyrite even after the addition of a large amount (1 x 10') M) of collector. Heavily oxidized (27 d) chalcocite remained unfloatable. However, longer oxidation of pyrite and chalcopyrite restored the floatability. Oxidation resulted in an electrically resistive, nonporous surface layer.

Jan 1, 1993

By Gyimah Kasali

Rapid Load Testing was performed as part of an extensive drilled pier testing program for the University of California Berkeley Capital Improvement Program. The purpose of the program was to: (1) Verify the axial compressive design capacity values for the planned 24" piers, and to estimate the capacity of the existing 30" CIDH piers, and (2) To evaluate the seismic performance of the proposed drilled shafts. The Fundex PLT was used since the loading period of the PLT is very similar to the period of a seismic event, making it an ideal tool to model the pier response to seismic events. "Performance-based design" of structures subject to seismic loads has been of particular interest to UC Berkeley Seismic Review Committee and the Pacific Earthquake Engineering Research Center. The comparison of static tests to Rapid Load testing also provided valuable correlations. The program represents one of the most comprehensive drilled pier test programs on the West Coast. The testing program consisted of Rapid Load Testing using the Fundex PLT on 6 drilled piers. Rapid Load Tests were followed by conventional static compression and tension tests on selected piers, followed by another cycle of rapid load tests on the statically tested piers. The piers featured extensive instrumentation to allow detailed interpretation of the test result. Correlations were drawn to compare static load test result to that of the PLT in the particular soil profile, and the PLT also provided the data to analyze the ultimate seismic capacity of the piers. The load test results indicate that the ratio of interpreted failure load from the PLT data to the corresponding load from the static load test data is about 1.2 to 1.3 for the clayey soils underlying the test site. The results also indicate that the PLT offers an economical approach to defining the stiffness of drilled pier foundations subjected to seismic loads for use in performance-based design.

Jan 1, 2002

By Denis Yaychuk, Gary Billingsley

The economic eva luation of a mineral property or mining venture should include the quantification of ri k as part of the analy is. The re ults of such an analysis provide the decision-makers not only with the most likely financial outcome and the probability of achieving that or any other outcome. but al o with a ranki ng of the relative impact of all the ri sk factors. These type of resu lts offer more complete information for investment and technical deci ions than the traditional cash flow/ ensitivity analysis. In addi tion. by attempting to quantify ri sk. the personnel providing the va ri able input are forced to take a much clo e r look at the data involved, and are fo rced to work together. the reby increa ing substantially the awa reness of the impact their work and others· work has on th e outcome of the analysis.

Jan 1, 1986

By Muhammad Zaka Emad

Cemented rockfill (CRF) is a mixture of rock aggregate and binder slurry. It is a stiff backfill, it is fast curing, its operation is simple, placement rate is reasonably high and no drainage is required. The main demerit of CRF is failure of exposed faces causing ore dilution, which can be associated with the fill placement method. This paper discusses the effects of two placement methods being practiced by mines and numerical modelling is used as a tool to evaluate stability of the backfill column. In the first method, practiced in longitudinal retreat mining of a narrow vein deposit, the rockfill is hauled and dumped into the stope with a LHD scooptram. Once dumped, cement slurry is sprayed into the stope. In the second method, a raise situated centrally above the mined stope is used to convey already mixed CRF into the stope. Stopes are mined out transversely in primary and secondary blocks in a sublevel stoping system. Problems of poor mixing in combination with both placement methods are discussed. The two backfill placement methods are analyzed for blast induced vibration damage using the dynamic Flac3D modelling technique accounting for rock mass and fill damping characteristics, and a pressure wave is used to simulate the blast vibrations. Fill heterogeneity has also been considered for the two cases and results are compared.

Jun 1, 2012

The fate of generations yet unborn lies in man's hands. Shall it be prosperity, a high standard of living, and the development of spiritual values; or ruin, misery, and a reversion to jungle law? World affairs move in high gear, at high tension, in many directions. Each nation fears the other fellow- races, crosses the white line on curves, skids, takes its half in the center; and the devil take the hindmost. For one, the United States is on the horns of dilemma; it must insure a flow of raw materials of industry and world-wide markets in order that the American people may maintain high standards of living, but the commitments of the United States cannot be fulfilled without trimming present standards of comfort and convenience back to the level of perhaps a quarter of a century ago. A way must be found to retreat without anarchy at home as well as abroad. Everything is relative and all things change, and change is the essence of civilization. It is now clear that man has not kept pace with changes of all kinds, some of them overnight, during the past 50 years. Conventionality has led to stagnation; man now seeks learning of all kinds at an accelerated pace, but men should not be educated beyond their native intelligence for they must be able to apply their education. There must be a resolute action now on 10 great challenges in regard to conservation of human and ma-

Jan 1, 1950

By F. S. Hoseinian, B. Rezai, E. Kowsari, M. Safari

In order to remove heavy metal ions from a large volume of wastewater with a low ion concentration, ion flotation appears to be promisingly effective. In the ion flotation process, because of the high ion removal percentage, the amount of water recovery percentage is a very important factor which determines the process efficiency. However, ion flotation suffers from relatively high collector concentration to achieve the high removal percentage to the desired limit, which subsequently increases the water recovery. In this study, functionalised graphene oxide (FGO) was synthesised, using a chemical method in the ion flotation process, applied as a collector for increasing process efficiency by reducing the collector consumption and water recovery. The high ion removal was achieved with both collectors of sodium dodecyl sulfate (SDS) and FGO, while the water recovery with a collector of SDS was 3.4% higher than that with a collector of FGO. The results indicated that the FGO could be effectively used for high ion removal and low water recovery in the ion flotation process. Keywords: Ion flotation, synthesised collector, ion removal, wastewater, water recovery

Jan 1, 2020

By P. C. Pistorius, D. Kruger, Y. Kacar

Because of its superior properties, stainless steel has been widely used for many applications. Nonmetallic inclusions can influence the quality of stainless steel products. A set of samples was used to track the response of inclusion composition during processing of a heat of titanium-bearing 18% chromium steel, from deoxidation after decarburization, to the solidified slab. The oxide inclusions responded as expected to additions of deoxidizers and calcium treatment, changing from silica to alumina and spinels, and then to calcium aluminates. The samples confirmed that titanium nitride can nucleate on liquid calcium aluminate during steel solidification.

Aug 1, 2021

By C. E. Hennig

On January 1, 1960 there were 310 petroleum refineries in the United States, with a crude-oil capacity of 9,901,424 barrels daily, according to the Bureau of Mines' annual survey. Compared with a year ago, this represents a net decrease of three in the number of refineries and an increase of 81,578, barrels per day in crude-oil throughput capacity. Continuing the trend to fewer units with greater individual throughput, the capacity of the average refinery in the United states increased during 1959 from 31,373 barrels per day to 31,740 barrels per day. Compared with the previous year, total crude-oil capacity of refineries on January 1, 1960 was lower in the Appalachian No. 1, Other Rocky Mountain, and Texas Gulf refinery districts. All other districts showed slight increases in capacity. At the beginning of 1960 the industry had under construction facilities that would increase the crude-oil capacity in the United States by 70,947 barrels per day. This was the smallest capacity increase under construction at the beginning of the year since 19460 Included in this construction of additional capacity were two new refineries, one in Michigan and another in Hawaii. In addition, the industry was constructing facilities to replace 50,250 barrels per day of existing crude-oil capacity.

Jan 1, 1960

By Gunnar Eriksson

Computer simulation has become an everyday practice in thennodynamic and materials research. Advanced thennochemical algorithms take into account heat transfer effects and salient reaction kinetics when applied for process models. In particular, the combination of mass transfer or overall reaction rates with multi-component Gibbs energy minimisation provides an effective tool for simulation of industrial thennochemical processes and processing of materials. In this work the combination of rate factors with the Gibbs energy technique was studied by using the novel program ChemSheet, which operates through Microsoft's Excel® spreadsheets. Such processes as, for example, CVD of pure silicon production, titania pigment manufacturing, vapour pressure of Mercury in amalgams (in Hg-Iamp manufacturing) and melting behaviour of low-temperature alloys have been modelled. Provided that the thennochemical data is available simulations can be performed with any thennodynamic system. The calculation can be performed as an affinity study without a particular reactor model or with a specific reactor scheme.

Jan 1, 2001

By Arthur T. Word

STANDING room only seemed to be the order at the annual session and luncheon of the Eastern magnetite committee. Gatehouse check at the former indicated at least 80, with 33 attending the luncheon - all the crowded facilities could handle. Chairman Crockett opened the meeting by calling upon Meredith E. Johnson, who presented his illustrated paper on "Prospecting for Iron Ore in New Jersey in 1943." This "wartime" brief was discussed by Lucien Eaton, P. W. Henry, and Chairman Crockett. H. E. Hawkes, Jr., of the U. S. Geological Survey, then presented his unscheduled paper on the "Magnetite Deposits of the Jersey Highlands." Discussion was by A. W. Pinger and Chairman Crockett. Fred E. Stiefel then described shaft sinking at the Fisher Hill mine of the Republic Steel Corp., giving a detailed description of how modern

Jan 1, 1944