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By M. Safiuddin

Within the mining industry, open-pit mining has progressed to a point where a 200-yard walking dragline is as conceivable today as a 35-yard dragline was just a few years ago. This is possible due to the technological advances and efforts of the excavator manufacturers, and the manufacturers of electrical equipment have always stayed abreast with them in meeting their requirements and in making available their experience with the latest control techniques and hardware from various fields for application in the mining industry. An electrician in the coal mines of Pennsylvania who had not heard the word "thyristor" a few years ago now wonders how the old excavators with Rototrols® and magamps could ever work. The thyristors, transistors and operational amplifiers which were considered too fragile and delicate for a rugged and severe application like the mining industry, today constitute the brain of an excavator control taking commands from the operator and giving signals to the muscles of the excavator to move the bucket within a few seconds. A giant 200-yd bucket filled with overburden moves within seconds of the operator's command. Digging cycles for these excavators range from 40 to 60 sec depending on the swing angle. With these tremendous production capabilities of the excavators, the equipment failures and downtime become very expensive, and the loss of return on large capital investment for such machines becomes intolerable. Even though these failures and downtimes cannot be avoided completely, a good preventive maintenance program can help reduce them, thus increasing the machine availability. As we shall see below, the causes for breakdowns and failures of electrical equipment can be analyzed and a good preventive maintenance program can be drawn up to eliminate most of these failures.

Jan 9, 1967

The development of Augered Cast-In-Place (ACIP) piles started in the late 1940's when several projects were performed by Intrusion-Prepakt, Inc. utilizing various techniques to place the piling. On some projects, a grout pipe was placed down the augered hole after the auger was withdrawn, and structural grout was pumped into the hole until grout appeared at the surface, after which the grout pipe was withdrawn. In some instances coarse aggregate was placed after a grout pipe was in place, and then the grout was intruded into the coarse aggregate, making a pile using the preplaced concrete method. Another method of forming augered piles used a system of driving or drilling a grout pipe through soils adjacent to the auger once the auger was drilled to the bottom elevation. The tip of the grout pipe was placed in close proximity to the tip of the auger. As the auger was withdrawn, grout was pumped through the grout pipe filling the augered hole from the bottom. After grout was observed at the surface, the grout pipe was withdrawn. In 1951, a patent was applied for by Raymond Patterson describing the above techniques along with a technique for placement of grout using a hollow stem auger and a removable plug or lead bit at the tip of the auger. The expendable plug or lead bit was removed by using grout pressure. The patent was granted in 1956. Around this same time other augered piling con-tractors began operations under licensed arrangements.

Jan 1, 2003

By E. R. Mueller

The natural lives of machines and components vary tremendously! Maintenance managers struggle constantly to maximize their equipment lives while minimizing their maintenance costs, but they normally lack the tools and techniques they need to do this properly. This paper proposes a methodology based on probabilities of failure and expected values for repairs that recognizes the variation among individual machines and components as well as the high costs associated with catastrophic failures. It enables a user to determine the optimum change-out intervals for many types of equipment. The approach proposed here is sophisticated enough to be reliable but simple enough to be applied by the maintenance staff on the shop floor. It will complement existing preventive and predictive maintenance programs.

Jan 1, 1995

By Zoë Mullard

The introduction of Web 2.0 platforms (also referred to as social media), with their architectures of participation, has ushered in a new era of technological interaction and information exchange that is changing the nature of corporate-community communications. Web 2.0 platforms give users the ability to generate data collaboratively, meaning that more stakeholders maintain the expectation of being able to contribute to online dialogue. In light of these changes, it is important for business to consider how social media can be used strategically to enhance stakeholder relationships and increase business efficiencies. This article provides three case studies of how different stakeholders in the mining industry are strategically using Web 2.0 platforms to communicate with target audiences. The case studies are based on the experience of respondents and from website observations, which were undertaken as part of a thesis research project by the first author (Mullard, 2010), focusing on the application of social media in the mining industry.

Jan 1, 2011

By W. A. Grosh

The Piquette Mining and Milling Co, operates a zinc mine and concentrating mill in the Upper Mississippi Valley zinc-lead district near Tennyson, Wis. The principal ore mineral is zinc sulfide, which occurs in limestones and dolomites of the Decorah formation. Exploration in the district is by churn drilling from the surface. An adit at the base of the ore zone provides access to the mine. A room-and- pillar mining method with irregular pillars is used. Drilling is done with Jumbo-mounted drills. The broken ore is loaded by crawler-mounted front-end loaders into diesel-powered trucks for haulage direct to the mill.

Jan 1, 1959

By Kenneth L. Bickel

During an underground mine fire, the importance of controlling the spread of smoke and toxic gases with suitable ventilation structures has been proven. However, under certain conditions, control of the propagation of the fire itself may be even more critical in insuring a safe mine evacuation. Fire doors offer the means for accomplishing both objectives. In 1978, the Bureau of Mines initiated research to evaluate the state of fire-door technology and develop and test a fire door suitable for large openings (10 by 12 ft or larger) in noncoal underground mines. This report discusses current fire-door technology in the context of the underground mine environment and the design, fabrication, lab testing, and in-mine field testing of a mineworthy fire door. This door has a 1.5-h fire resistance rating and limits temperature rise across the door to 2500 F during the first 30 min of fire exposure.

Jan 1, 1987

By John A. Rusnak

"This paper discusses the variation of coal strength based on the megascopic coal lithotypes for Central Appalachian high-volatile A coal beds. The composition of coal beds is complex and variable, depending on the depositional environment associated with original plant material, inflow of clastic material, and water level fluctuations in the original swamp/mire environment. Thus, different types of coal and sediment are formed within each coal bed. These differences in coal composition were first classified by Marie Stopes, a paleobotanist, in 1919. The classic coal megascopic lithotypes are vitrain, clarain, and durain, which correspond to bright, bright banded, and dull coal, respectively. Stopes also identified that the lithotype fusain, which is mineral charcoal, has no inherent strength and can act as a plane of discontinuity. In this study, two other coal-bed lithologies are also considered—bone and carbonaceous shale. This makes for a comprehensive suite of coal-bed stratigraphic components apart from rock partings. A total of 1,000 uniaxial compressive strength (UCS) and 440 indirect tensile strength (ITS) tests were conducted on cores from southern West Virginia that were specifically logged and described using the megascopic coal lithotype nomenclature. Statistical analysis is presented showing the results for each lithotype group with mechanical properties correlated to the lithotype. Previous studies have analyzed the mechanical breakage properties associated with coal lithotypes, which correlate well with these results. However, coal rank does appear to be a contributing factor, and this study is confined to only high-volatile A bituminous rank. Application of these results would be well suited to a rock mass classification system to address coal pillar rib stability. This would allow for rib support design and implementation to consider relative coal strength by visual observation of the seam stratigraphy through ongoing observations within a mine. Changes in seam composition can be readily identified, allowing the adjustment in rib support design. Another application would be for the determination of numerical modeling inputs based on detailed seam stratigraphy. However, these results, even with the standard strength reduction criteria, may not be applicable to currently accepted empirical coal pillar design procedures."

Jan 1, 2017

By A. J. Kraemer

This paper is the second and concluding report of the results of the Bureau of Mines' twenty-second semiannual survey of motor fuel marketed in the United States. The first paper Was published as Report of Investigations 3063 and reported data relating to gravity, vapor pressure and distillation range of the samples. The present paper deals particularly with results of the determination of copper strip corrosion (method 530.22), color (method 10.11), sulphur content by the lamp method, copper dish evaporation residue (method 530.1), and "gum" content as given by the steam-oven method as developed by the Bureau of Mines. The price at the time the sample was taken and the tax are also stated for each sample. The sample numbers used throughout this report are identical with those used in Report of Investigations 3063; for example, No. 225 of this report is the same sample as No. 225 of Report of Investigations 3063. This is the first semiannual motor gasoline survey of the Bureau 6f Mines in which some data were obtained on antiknock values for samples collected in the survey. The Bureau of Mines is not provided with equipment for making these tests in its own laboratories, but composite samples were tested in the laboratories of the Bureau of Standards and the report on these samples is given as a supplement to this paper (pp. 11 to 14).

Jan 1, 1931

By S. Dey, C. Bhar, S. K. Mandal

Loading and hauling of ore and waste are the key operations of an opencast coal mine and entail a high operational cost. The productivity of a mine can be increased by reducing the cycle time of loading equipment as well as utilizing dumpers optimally. In this paper we discuss the impact of rock type, bucket fill factor, rock fragmentation, the height of the cut, and angle of swing of the bucket on shovel performance. A time study is conducted on shovels in an opencast coal mine with experimental blasts of rocks to assess the impact of different factors on the performance of the shovel. Based on the data, the authors applied multiple regression (MR) and artificial neural network (ANN) techniques to develop different models for the prediction of the shovel cycle time. Developed models are validated by comparing the predicted data with actual field data. With the help of the best model, the plausible fleet size is determined in order to utilize the shovel and dumper optimally and to improve the performance of shovel–dumper operation.

Oct 1, 2022

By F. Calizaya

A booster fan is an underground fan installed in series with a main surface fan and used to boost the air pressure of the ventilation air passing through it. To accomplish this objective, the fan is installed in a permanent stopping and equipped with airlock doors, a monitoring system, and interlocking devices between main and booster fan controls. The stopping and doors are used to prevent flow recirculation, and the monitors to ensure safe operation of the fan. A booster fan, properly sized and sited, can be used to create safe work conditions and allow the extraction of minerals from areas that would otherwise be uneconomic to mine. In deep and large mines with heavy emissions of air contaminants, the required quantities of air can only be supplied by using high pressure fans. These fans will inevitably induce significant losses of fresh airflow through the stoppings and doors. For well defined ventilation circuits, booster fans can be used to decrease the main fan pressures and reduce the leakage flows. However, this will require a good understanding of the correct ventilation practice, from planning to operation and maintenance of booster fans. The objective of this study is to investigate the conditions under which booster fans can be used safely and efficiently in underground coal mines. Specifically, the study is directed at (1) collecting reliable information on airway resistances and flow requirements from two large U.S coal mines, (2) collecting fan performance data from one or more existing coal mine where booster fans are used regularly, (3) monitoring the performance of booster fans in a laboratory model and an experimental mine, (4) developing a booster fan selection method to assist the ventilation engineer at the planning stage, and (5) training six M.S. or Ph.D. graduate students in advanced mine ventilation.

Jan 1, 2010

The principal activities of the Bureau of Mines Explosives Research Center (now Safety Research Center) during fiscal year 1968 (July 1, 1967, to June 30, 1968) are reviewed in part 1. Part 2 presents short abstracts of the publications issued during this period in the Bureau series and in other media. Part 3 describes a short study on the thermal decomposition of RDX and HMX not destined for publication elsewhere. ACKNOWLEDGMENTS The Bureau gratefully acknowledges the support received through cooperative agreement in fiscal year 1968 from The Manufacturing Chemists Association.

Jan 1, 1970

By Albert L. Toenges, Henry E. Dekay, James N. Scudder

Support of the immediate roof in coal mines is essential for their safe operation, and timbers are the most common means of support. Their effectiveness depends upon their resistance to decay. The theory has been advanced by some mine operators that rock dust, which is applied to ccal-mine workings to prevent propagation of explosions, accelerates the decay of mine timbers. As the results of part 1 of this study were inconclusive, the study was continued. Its principal objectives are: 1. To determine the effect of rock dusting upon decay of mine timber. 2. To compare the extent of decay of timbers in two mines in which underground conditions are similar. 3. To determine the loss in strength of the timbers after exposure to mine atmosphere. The studies were carried on in the Crucible mine of the Crucible Fuel Co. where the first part of this study was made, and in the Isabella mine of the Weirton Coal Co. The mines are on the Monongehela River and are adjacent.

May 1, 1943

By Venugopal Tammishetti

One of the important technological challenges facing the iron ore industry in India is to find commercially viable technologies to process alumina rich iron ore fines and slimes. The key to solving this problem lies in developing selective reagents for the separation of iron oxide minerals from associated gangue minerals like quartz, gibbsite, kaolinite and montmorillonite. We present in this paper our successful results on the dispersion-flocculation of three different natural iron ore slime samples from mines in India using the reagent combination of PVP dispersant and corn starch flocculent. All the three samples contained hematite, goethite, kaolinite and gibbsite minerals as confirmed by X-Ray Diffraction (XRD) analysis. The effect of various process parameters such as pH, dosage of reagents, settling time and pulp density was studied. We were able to produce a concentrate assaying 66.2% Fe and <2% Al with a yield of 67.4% by weight (with a recovery of 77% of iron values) using PVP (1 ppm dosage) and corn starch (20 ppm) for one of the slime sample (Sample I) assaying 58.2% iron (Fe) and 3.8% aluminium (Al). The XRD analysis of settled and dispersed fractions revealed that alumina-containing minerals like clay and gibbsite mostly remain in the dispersed phase while iron-bearing minerals tend to concentrate in the flocculated fraction. Keywords: iron ore, slime, flocculation, dispersion, beneficiation, starch, polyvinylpyrrolidone

Sep 1, 2012

By D. H. Chambers, Arnold M. Lansche

Electro recovery by amalgam methods was investigated to determine the feasibility of recovering pure cadmium from cadmium sponge produced during purification of zinc electrolyte at electrolytic zinc plants . Actual material used in this work was air- oxidized cadmium sponge . An acid rinse and zinc displacement technique was developed to amalgamate this oxidized cadmium . ( In - plant use of the recovery process would probably not require this step because of the fresh state of the sponge . ) Zinc was completely removed from amalgamated sponge by selective oxidation with air . Zinc - free cadmium amalgam was circulated by an electromagnetic pump through an electrolytic cell where cadmium of 99.9+ percent purity was electrodeposited onto a rotating aluminum cathode . Polarographic methods were developed for determining cadmium and zinc in mercury and in sulfuric acid solution .

Jan 1, 1964

By Sydney H. Ball

A QUARTER of a century ago, a pessimistic Belgian financier in conversation with the founder of the Belgian Congo, that great ruler, Leopold II, emphasized the danger to the colony should the synthesis of rubber be discovered. The king replied, "I do not worry. The Congo has had its ivory period; it now has its rubber period. Tomorrow it will have that of its mineral wealth; eventually that of agricultural products." That "tomorrow" arrived some twenty years ago. Through her mines the Belgian Congo has survived the present depression, and her mines for the next decade will safeguard her. The Congo, in turn. is the surest foundation industrially and financially of Belgium itself. In few, if any, political units is mining as dominant as in the Belgian Congo. In 1930, 1931 and 1932 mineral products represented respectively 67.9 per cent. 70.5 per cent and 59.3 per cent, of the total exports. In 1933 for each white person in the colony, there was produced about $1,675 worth of gold, diamonds, copper, tin ore and minor mineral products and in 1930 the per capita production, notwithstanding the larger population, was almost $2,000.

Jan 1, 1934

By P Hawke, J Hurst, B KrapeP

Hancock Prospecting Pty Ltd (HPPL) drilled two deep diamond stratigraphic holes (ECD0001 and RHD0296) within the eastern Fortescue Valley in the Pilbara of Western Australia. Located south of the Roy Hill Iron Ore project, the holes aimed to define the stratigraphy of the Marra Mamba Iron Formation (MMIF) of the Chichester Range and its south-dipping extensions below recent cover. Previous attempts to define the MMIF of the Chichester Range have resulted in differing interpretations due to the data available at the time.The unweathered MMIF beneath the Fortescue Valley in the HPPL drill holes is characterised by dolomitic carbonate interbedded with stilpnomelane-rich shales, chert and banded iron formation (BIF) with hematite staining. This intersection equates to ~75 m of carbonate-facies iron formation, as opposed to the ~230 m thick oxide-facies BIF and shale sequence encountered south of the Fortescue Valley.Various detailed geological core analyses and interpretations from ECD0001 and RHD0296 were integrated with regional diamond and reverse circulation (RC) holes from across the Fortescue Valley. Interpretation of the data indicates that the eastern Fortescue Valley MMIF represents a thinned thickness sequence of the whole formation. The MMIF of the Chichester Range and Fortescue Valley has gamma logs that correlate strongly in parts to the type section used for MMIF south of the Fortescue Valley. Therefore, the outcropping MMIF in the Chichester Range represents an eroded equivalent of the æreducedÆ thickness MMIF observed in ECD0001 and RHD0296.Data from deep diamond drill holes across the valley, from the Hamersley Basin to the Carawine Basin, were correlated. The correlation shows that the depositional site of the MMIF in the HPPL diamond drill holes is consistent with a proximal ramp setting, in which iron-rich shales wedge up-palaeoslope and shelf-derived carbonate turbidites wedge down-palaeoslope. Not only is it the occurrence of these shales that define the MMIF, but they also determine the northward potential to develop orebodies, as they are the source of iron from which iron-rich oxides and carbonates of metamorphic or diagenetic origin form.CITATION:Hurst, J, KrapeP, B and Hawke, P, 2013. Stratigraphy of the Marra Mamba iron formation within the Chichester Range and its implications for iron ore genesis at Roy Hill - evidence from deep diamond drill holes within the East Fortescue Valley, in Proceedings Iron Ore 2013 , pp 91-106 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By G. Mark Aylmore

Various processes have been developed using a combination of elevated temperature and chemical treatment processing to recover Li from silicate minerals. To facilitate further process development, a comprehensive understanding of the deportment of Li and associated minerals in ore bodies is essential to allow the industry to predict the response of ore reserves to metallurgical treatment options. This paper describes results from the integrated use of the John de Laeter Centre’s state of the art analytical and mass spectrometry techniques to characterise a selection of Li bearing ore bodies and determine their amenability to potential processing options for the extraction of Li. The mineralogy, mineral associations, and liberation characteristics of ore-bearing and gangue minerals were characterised using a combination of the TIMA and XRPD studies. The Li content and distribution within minerals were defined using LA-ICPMS and field emission scanning electron microscopy techniques (EBSD, ToF-SIMS) and atomic probe microscopy.

By D. R. Torgoson, Th. G. Sahama

"This paper contains some new thermodynamic data for silicates in the series Mg2SiO4-Fe2siO4 and MgSiO3-FeSiO3 and gives the results of a thermodynamic attack on the problems of stability end parageneses.. Although some data are lacking satisfactory agreement with mineralogical and petrological observations is indicated.The use of thermodynamic methods in mineralogy and petrology has been rather limited, because accurate thermal data, especially for the more complicated and more important rock-forming minerals, have been too scanty to permit any systematic application to problems in those fields. It is, nevertheless, a fascinating task to investigate to what extent the mode of occurrence and the stability relations of the minerals and mineral parageneses, as revealed by petrological and mineralogical observations, agree with predictions of thermodynamics. At the present stage of development calorimetric data are needed for most of the abundant silicate minerals.Measurement of the heats of solution in hydrofluoric acid of minerals in the series Mg2SiO4-Fe2SiO4 and MgSiO3-FeSiO3 affords a ready means of obtaining their heats of formation from the oxides. Combination of such data with entropy and heat-capacity values gives a means of obtaining free energies of formation from the oxides, which, in turn, are connected di¬rectly with stability and paragenoses.The two silicates of magnesium, Mg2SiO4 and MgSi03, occur as rock-forming constituents as forsterite and clinoenstatite or enstatite. The orthosilicate (forsterite) forms a series of isomorphic mixtures with ferrous-orthosilicate (fayalite). The continuity of this series, suggested by petrological observations, has boon proved experimentally by Bowon and Shairer.4/ The present work shows that those minerals constitute a series of perfect solid solutions - that is, a series of solid solutions for which heats of formation from the individual pure silicates, Mg2Si04 and Fe2SiO4, aro negligibly small.The metasilicates of magnesium and iron also form an isomorphic series. However, this series differs from the forstorito-fayalite series in the fact that the most iron-rich mixtures, between about En10Fs90 and pure Fs, appear to be unstable with respect to the paragenesis iron-rich olivine plus quartz. The supposed instability of pure FeSiO3 as a crystalline compound, at least at high and at moderate temperatures, is remarkable, as no crystal struc¬tural reason for such instability is apparent. The present work indicates, also, that these minerals form a perfect series of solid solutions and throws additional light on the instability question.In the following, the samples used in this investigation will be described. For each of the natural olivines and orthopyroxenes, with the exception of sample L, a chemical analysis was made of the purified and actually used fraction. All the analytical work was carried cut by Oleg v. Knorring, and the specific gravity determinations, by moans of a pycnomctcr, by Oiva Joensuu, both of the University of Helsinki, Finland. The determinations of the optical properties were made by Mrs. Toini Mikkola, of the Geological Survey of Finland."

Feb 1, 1949

By Carl Fisher

A microseismic roof fall warning system was field tested in Western and Eastern coal mines in the United States to better define the capabilities and limitations of the microseismic method in predicting roof fall Microseismic event and energy type data were obtained and documented for twenty-three coal mine roof falls. Field test results indicate that both the microseismic event and energy methods, as applied in this development effort, have a high probability for successful application in a commercially practical roof fall warning system. Based on the results and experience obtained during field testing, a commercial prototype microseismic roof fall warning system was designed and constructed. Although it was the intent of the program to field test the commercial prototype system, delays in equipment fabrication and contract time limitations did not permit field testing.

Jan 1, 1980

By Gopala N. Krishnan

The most promising candidate for the recovery of alumina from non-bauxitic sources is the leaching of clay by HCL acid followed by crystallization of aluminum chloride hexahydrate (ACH) by hydrogen chloride sparging. Hydrothermal precipitation of boehmite ( ?-A100H) from aluminum chloride solution will simplify the process, will reduce energy consumption and will eliminate corrosion problems involved in calcination of ACH to obtain alumina. This report summarizes the results of Phase I of a program to study the precipitation of boehmite from AlC13 solutions. The amount of boehmite precipitation from dilute A1C13 solutions (5 wt%) is . negligible below 200°C. Above 200°C the precipitation increases with increasing temperature approaching 40% at 300°C. Addition of HCl acid to the dilute A1C13 solution even in small quantities drastically reduces boehmite precipitation. Solution impurities such as Fe, Ca, Mg, or Na substantially promote the precipitation of boehmite. No precipitation is observed from concentrated A1C13 solution (30wt%) representing the leach liquor.

Jan 1, 1980