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By Lewis Dr. Wade

It is really an honor and pleasure to be here at the 231d International Conference on Ground Control in Mining. My name is Lew Wade. Until recently I served as the Associate Director of Mining for NIOSH. That's a position that I recently moved out of and that position is now filled by Dr. Jeffery Kohler. I now serve as the Sr. Science Advisor to the NIOSH Director. The topic of my talk today will be coal mine ground control, a look back at the last 30 years, and then a brief look forward. I will start by talking about coal mine ground control statistics and with just a brief look, those statistics clearly show that you people are making a difference and there have been tremendous improvements. I'll then look at reasons for those improvements and those will include people working together (this conference being a prefect example of that), as well as technology development. In the area of technology development, I will give you my top-ten list of technology developments in the area of coal mine ground control. Then I'll end with a look towards the future and point to some possible future developments. Then, I will be so bold as to issue some challenges to the participants of this conference. Again, if you take the broad look back at underground coal mine roof falls and ground fatalities, you see this tremendous improvement that we have all come to appreciate. We have all been a part of improving the safety conditions for our underground miners and the number of fatalities is orders of magnitude less than what it was at the turn of the previous century. We have every reason to be pleased and proud of what we have been able to accomplish. Now, the question is why. What are the reasons for those improvements? Just look around this room. You see evidence of what I think are one of the principle reasons: miners, mine operators, government workers and researchers, equipment suppliers, people in research and academia working together. Coming together and sharing at a Conference like this over the last 23 years.

Jan 1, 2005

Organization Place Date 1919 American Chemical Society Philadelphia, Pa. Sept. 2-6 National Assn. of Stationary Engineers Huntington, W. Va. Sept. 8 American Peat Society Minneapolis, Minn. Sept. 22-24 American Iron, Steel Electrical Engineers St. Louis, Mo. Sept. 22-26 American Institute of Min. and Met. Engineers. Chicago, Ill. Sept. 22-27 American Steel Treaters' Society, First Annual Convention Chicago, 111. Sept. 22-27 National Exposition of Chemical Industries.... Chicago, Ill. Sept. 22-27 National Safety Council Cleveland, O. Sept. 29-Oct: 2 American Foundrymen's Association Philadelphia, Pa. Sept. 29-Oct. 4

Jan 9, 1919

By A. H. Cronk

This paper is one of a series being prepared by the United States Bureau of Mines on mining methods and costs in the different mining districts. The mining methods described in this paper are employed by one of the large mines in the Illinois fluorspar district. The mine is located at Rosiclare, Ill., and shipments are made over the Illinois Central Railroad: and by barge on the Ohio River.

Jan 1, 1930

By Asmo Vartiainen

Background of Direct-to-Blister Flash Smelting is discussed; especially slag chemistry relating to copper solubility, slag fluidity and impurity behavior. In December, 2000, Mini-pilot Flash Smelting test runs were carried out at Outokumpu Research Oy to produce blister copper from Chilean concentrate and white metal and from a mixture of them. Tested slag types were iron silicate slag, ferrous calcium silicate slag and calcium ferrite slag with different slag compositions and different concentrate/white metal ratios. The test runs were successful. The fluxing effect of copper oxide was clearly demonstrated and ferrous calcium silicate slags remained fluid on a very wide liquidus range. The distribution of arsenic between ferrous calcium silicate slag and blister copper is much higher than between iron silicate slag and blister copper. This successful test run with the new slag type offer new possibilities in Direct-to-Blister process design.

Jan 1, 2003

By Rameshwar Sah, Bharath Kumar Shanmugam, Govinda Raj Mandela, Marutiram Kaza, Harsha Vardhan, Harish Hanumanthappa

Iron ores obtained from different sources differ in their chemical and physical properties. These variations make the process of grinding a difficult task. The work carried out in this context focuses on three different samples of iron ore, viz., high silica high alumina, low silica high alumina, and low silica low alumina. The grinding process for all the three iron ores is carried out individually in Bond’s ball mill and the total retention time taken by each iron ore sample is calculated. The present investigation focuses on utilizing the calculated retention time of the iron ore as a standard grinding reference time to the laboratory ball mill for optimizing the grinding time of each ore. The desired P80 (150 μm) with an acceptable range of hematite liberation (> 75%) was obtained in the laboratory ball mill after reducing 6 min from the total retention time taken in the Bond ball mill.

By Yuting Xue, Mark Van Dyke, Joe Wickline

The understanding of coal mine roof lithology is a critical component in the determination of engineering solutions for roof control. Coreholes were the first technology available to determine lithology of the roof in reserve areas, but coreholes are typically drilled 500–2,500 ft apart due to their cost and sometimes reach more than $125,000 dollars per hole, depending on mine conditions. The next method developed to bridge this gap was the fiber-optic scope which is utilized in the roof at the faces of underground development. High-end fiber-optic scopes can also be costly (20,000–40,000 dollars) but are more affordable than drilling a corehole, and the information can be processed immediately to make quick roof support determinations. The fiberscope can be operated wherever a roof bolter can drill a hole, and there are no restrictions related to property owners, proximity to streams, elevation changes, etc. The latest borescoping method utilized by mining companies is the use of videoscopes. Videoscopes and all borescopes in general are limited by the lengths of the scope and the length of the borehole drilled in the mine. Videoscopes have the advantage of being able to record video while examining the roof lithology. The information can be recorded quickly underground and then be examined on the surface which allows anyone to capture the video so that a geologist can make lithology descriptions without ever going underground. In the past, videoscopes had limited resolution, a short battery life, were fragile and were relatively costly. As technology progresses, videoscopes have become more affordable, have increased battery life, and offer enhanced 1080p resolution. With the broader availability of affordable videoscopes, videoscopes can be more readily used in various mine environments at every active section underground. This paper will discuss the types of videoscopes available, the features that will aid in lithology description/identification, the deployment methods pertaining to supplemental roof support recommendations, and an advanced methodology to enhance accuracy in understanding roof lithology.

Feb 1, 2025

By J. W. JESSUH

TO certain people the name of Northern Rhodesia brings only a vague recollection of a distant country somewhere in Africa; to others, it means a big game territory and the opportunity for excellent shooting; to some, a land of sunshine and peace; but to mining men the name signifies the land where the latest discoveries of copper ore are astonishing the mining world and bid fair, in a few years, to make Northern Rhodesia one of the largest copper- producing countries. There is a fascination about this part of the globe that is somewhat similar to southern California, and at the same time there is that feeling of mystery peculiar to a tropical climate. Perhaps it is the isolation, the fear of wild animals, or the influence of an undefinable something which cannot be expressed.

Jan 1, 1931

By Eldon Keith Stanek

This annual report deals with a multi-faceted research effort to increase mine electrical system safety. The project can be broken down into six task areas. Task one deals with the development of tests and instrumentation to perform these test- that are designed to detect incipient faults on mine power systems. This program also encompasses evaluation of the tests and automation of data collection and recording using a microprocessor. Task two concerns the prediction and suppression of mine electrical transients. This program involves digital simulation and suppression hardware evaluation. Task three deals with the reliability and fail safe assessment of various components of the mine electrical system including both the protective system and bulk power system components. Task three deals with theoretical analysis, laboratory testing and in-situ testing in coal mines of power system devices. Task four is an effort to design an optimal mine electrical distribution system. The initial effort is along the lines of refining analytical tools such as the load flow model. Task five is an attempt to optimize the selection of molded case circuit breakers makes or models on the basis of total annual cost. Task six assesses the availability of equipment to satisfy existing federal regulations.

Jan 1, 1977

By N. H. Emmons

An interesting development of copper blast-furnace construction has been brought about in adapting the blast-furnace to be a "burner" for sulphuric acid making. When the Tennessee Copper Co. first decided to construct an acid-plant, the standard type of brick-top furnace, supported by structural steel, was the only one in use at its plant. All the tests for temperature and strength of gas had been made on these furnaces, and had been satisfactory. When, however, the acid-plant was put on the flue, and the flue had to have a damper put in it to force the gas into that plant, troubles began. The furnaces were fairly tight, and for a few months the work was quite satisfactory. Fig. 1 shows the old type of furnace-top used at the start. It was soon found that this top would not stand the temperatures, particularly when dampered back, as was necessary to force the gas into the Glover towers. The structural steel, of which the furnace skeleton was constructed, warped and twisted so badly that it was not safe to use the furnaccs. This effect is shown by Fig. 2, which is a photograph of old No. 4 furnace, after the brick-work had been removed. It became apparent that a new type of top mas necessary and the engineering force was started on the design of a new furnace-top, with the result that a low top, with brick-lined flues at each end below the feed-floor, leading to the main concrete dust-chamber, was constructed. This furnace, No. 7, is shown in Fig. 3. The charging-doors are made of cast-iron sections, three sections to a door, and three doors to a side. A door to the furnace was made of east copper, but the heat was great that the copper bent readily, due to the jarring of its

Jan 1, 1911

By E. Watkins, J. C. LeRoy, A. Vivyurka

"TAILINGS REVEGETATIONWelcome to the Revegetation Session. My instructions are to introduce the Speakers and to provide a general introduction.I do the latter with humility not only because of a lack of personal experience or because tailings revegation is not well established technology, but because any general statement on a country or industry as diverse as the Canadian Mining Industry is bound to be wrong somewhere.Laying aside normal standards of accuracy I proceed as follows:In considering the question of tailings revegetation, one asks two basic questions:1. What ought to be done?2. What can be done?The first question can be broken down into three kinds of criteria or objectives:a) Legislativeb) Technicalc) AestheticThe first I leave to the politicians and the last I will avoid. Aesthetics is the philosphy of taste. It is concerned with the appreciation of things rather than what they really are. It is much easier to get into an argument on aesthetics than to get out of it feeling you have said something of consequence.Technical criteria can be divided into the following sub-objectives: 1. To isolate the tailings basin so surrounding land is not degraded. The first step here is stabilization of the surface to prevent wind and water erosion."

Jan 1, 1975

By Fernando O. Boechat

Com a redução da oferta de minério granulado de boa qualidade no mercado mundial e as restrições ambientais à sinterização, as pelotas de minério de ferro passaram a ocupar um papel importante como matéria prima para produção de ferro primário. Entretanto, embora apresentem maior resistência à degradação, as pelotas ainda sofrem com este problema, embora em menor magnitude, quando comparadas com granulados. Pode-se identificar a degradação das pelotas de minério de ferro em duas etapas, durante o manuseio e sob redução. Uma vez que vários estudos já analisaram a degradação durante o manuseio, a degradação durante a redução torna-se um assunto relevante e pouco explorado. Assim, o presente trabalho avaliou as energias envolvidas no movimento da carga ao longo de um forno de redução direta do tipo Midrex, usando o método dos elementos discretos. Para isso, foi utilizado o software EDEM® para obtenção das energias dissipadas durante as colisões das partículas. Aplicando estas energias ao modelo mecanicista proposto por Tavares e Carvalho [4] para fragmentação das partículas foi possível estimar a taxa de geração de finos no interior do forno. Estes resultados foram utilizados na previsão da degradação mecânica de pelotas no interior do forno, que previu a geração de 1,2 a 2,6% de finos gerados em um forno Minimod®, dependendo das premissas usadas.

Aug 1, 2018

By Donald E. Redmon

This Bureau of Mines report examines the injury experience in the quarrying industry for the years 1968-69. Twenty-eight tables for each year are presented in which disabling work injuries are summarized by department, source of injury, extent of disability, part of body injured, and nature of injury. Correlative information on employment, worktime, and operating activity is also presented.

Jan 1, 1973

By D. Anthony, R. A. Williams, R. Raponi

Barrick Gold Corporation in conjunction with SNC Lavalin Engineers and Constructors have developed basic engineering design for counter current decantation thickener (CCD) plants capable of processing 44 000 t/d. To achieve this throughput in a single train, the largest high-rate thickeners installed to date have been utilized in concert with large process slurry and solution transport systems. Process reliability and plant operability and maintainability have been carefully considered in order to develop a practical, yet cost effective design. The design also incorporates the challenges associated with installation of large equipment and structures in a remote location, with a climatically hostile environment, situated in a high seismic activity zone.

Jan 1, 2002

By S. I. Angadi, C. Eswaraiah, Sunil Kumar Tripathy, T. Santosh, Nilima Dash

Banded hematite quartzite (BHQ) and banded hematite jasper (BHJ) ores represent a promising potential iron ore resource in the near future. The hematite and quartz in BHQ and the hematite and jasper in BHJ are closely related and require fine grinding for the liberation of hematite phases. The present study investigates the mineralogical features and comminution properties of BHQ and BHJ ores. In the BHQ ore, it is observed that thick bands of hematite have fine inclusions of silicate minerals, whereas silica bands have few grains of iron-bearing minerals. The hematite and quartz minerals in the iron and silicate bands of the BHJ ore appear to be more intricately associated and complex in nature, presenting difficulties for liberation. Bond work index studies were carried out for the BHQ and BHJ ores with different product fineness in order to evaluate the energy requirements in fine grinding. A higher Bond work index value was found for the BHJ ore (15.4 kWh/ton) than for the BHQ ore (12.4 kWh/ton). A decrease in the product particle size was associated with an increase in the work index value. Single-particle breakage experiments were designed by varying feed particle size and input energy. The specific energy consumption for the BHJ ore was higher than that for the BHQ ore. The comminution parameters showed that the BHJ ore is harder to grind than the BHQ ore, which may be due to the mineral composition and association of hematite phases with the silicates.

By F. J. Wiebel

"INTRODUCTION As a result of a general survey of the iron-ore deposits of Califor¬nia, the Bessemer was one shown to offer possibilities of developing com¬mercial ore reserves. Surveying and exploring were done at the request of Congress for an investigation of raw materials for the production of steel.A wartime steel plant has been established at Fontana, San Bernardino County, and a backlog of iron-ore reserve for the maintenance of permanent steel industry on the West Coast will be of National benefit in the postwar period.W. D. McMillan, a mining engineer the Bureau of Mines, examined the property in May 1942, and it was reexamined by D. W. Butner, also of the Bureau, in October 1943. Geophysical work was done by the Bureau in 1944, and the property was explored by diamond drilling from April to August 1944 and February to SeptemberACKNOWLEDGMENTSIn its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contri¬bution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, under the direction of Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, under the direction of R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests."

May 1, 1947

By Adeyemi Adesina, Subhabrata Mishra, Syed Mohammed Mustakim, Malaya Kumar Jena, Shaswat Kumar Das

Utilization of low-grade manganese ore adopting the carbothermic reduction roasting process is a proven method to produce high-grade manganese ore. To minimize industrial waste and protect the environment, gas cleaning plant sludge (GCPS), which is a solid waste from steel industries, was employed as a reductant to perform the reduction roasting process. The optimum conditions to carry out reduction roasting of the low-grade manganese ore were found to be: a roasting temperature of 950 °C, a residence time of 2 h, 40% GCPS as reductant, and magnetic separation at 5000 G for a manganese ore size of –10 mm. A lowgrade manganese ore comprising Mn grade 31.27% and Fe grade 19.78% having a Mn/Fe ratio of 1.58 containing a high silica content of 26.48% was used for the carbothermic reduction roasting having mineral phases of pyrolusite (MnO2) and hematite (Fe2O3) as found from XRD. The gangue minerals were separated during the magnetic separation, and the upgraded product was obtained, which reached a maximum value of TMn 49.5% with RMn 76.55% and TFe 62.19% with RFe 42.51%. In the study, activated charcoal (AC) was also taken as a reductant for comparative analysis; the experimental results revealed that GPCS performed better than that of the AC, showing potential to be used as a reductant in metallurgical industries. However, the resultedMn/Fe ratio was very low for the reduced sample; therefore, it can be used for smelting along with high-grade manganese ores as a feed.

Mar 5, 2021

By Juan Camus

To understand why some companies excel in creating value, Jim Collins (2001) and a group of postgraduate business students engaged in a comprehensive, five-year research project. They examined 1,435 U.S. companies for more than 40 years, seeking those that made significant improvements in their financial performance over time. The distinctive pattern sought was: ?Fifteen-year cumulative stock returns at or below the general stock market, punctuated by a transition point, then cumulative returns at least three times the market over the next 15 years. ?The search identified 11 outperforming companies, all in different industries, that were called the ?good to great? companies. To contrast these companies with similar peers within the same industry, the search also selected a group of comparison companies that failed to make the leap from good to great. Collins then set out to examine the transition point. What distinguishing features did the good-to-great companies have that their industry counterparts did not? At the heart of the findings about these outstanding companies is what Collins refers to as the ?hedgehog concept? ? how to find the one big thing that the company must focus on. According to Collins, those who built the good-to-great companies were, to one degree or another, hedgehogs. Those who led the comparison companies tended to be foxes, never gaining the clarifying advantage of a hedgehog concept, being instead scattered, diffused and inconsistent. This insight is complemented by Peter Drucker (2004), an influential management guru, who asserts that the first question an effective executive should ask is: ?what needs to be done?? Asking this question and taking it seriously, he asserts, is crucial for managerial success; and that the answer almost always has more than one urgent task, but the effective leader only concentrates on one task. In this last respect, Drucker emphasizes: ?If they [executives] are among the sizeable minority who work best with a change of pace in the working day, they pick two tasks. I have never encountered an executive who is effective while tackling more than two tasks at a time.?

Jan 1, 2011

By G. L. Schroeder

Investigations were conducted at two underground locations, foreman's room and 5702 area, of the Kermac Nuclear Fuels Corp. uranium mining installation, Ambrosia Lake, New Mexico. The rock environment is stratified sandstone. Pressures were varied from minus 0.4 an Hg to plus 3.8 cm Hg with respect to barometric pressure, and were maintained for periods ranging from several hours to 21 days. One cm Hg overpressure (-1.5% of normal barometric pressure) produced a 20-fold decrease in Rn flux into the foreman's room as compared to the Rn flux observed during dilution ventilation. The 5702 area experienced a 5-fold decrease in Rn flux for a similar overpressure. During 21 days of continuous 1 cm Hg overpressure in the 5702 area this reduced Rn flux was maintained. The smaller reduction in flux for the 5702 area results in part from the proximity of the foreman's room to a non-pressured area and the presence of an impermeable shale lens overlying the ceiling of the 5702 area. A 0.4 cm Hg underpressure of the 5702 area increased the Rn flux into the area by 3-fold over the non-pressured value. A barometric pressure influence on Rn flux into the mine and on air Rn concentrations in non-pressurd areas of the mine was measured. A falling barometric pressure causes an increase in the flux of interstitial gas into the mine; a rising barometric pressure decreases this flux. These effects are not seen in overpressured mine areas. Radon concentrations in rock interstices show, during overpressure, decreases of all locations monitored except in the immediate vicinity of the shale lens above the 5702 area ceiling. These reductions are the result of air flowing from the mine into the rock interstices under the influence of the pressure gradient induced by the overpressure. The relative humidity of the 5702 area was reduced after 2 days of 1 cm Hg overpressure from a pre-overpressure value of 96% to 81%. The control of harmful or noisesome gases which emanate into underground mining areas from surrounding rocks is often a costly necessity. In uranium (U) mines this problem is presented by the high interstitial concentrations of radon-222 (Rn), a radioactive noble gas of 3.82-day half-period, formed in the decay scheme of U238, and the relative ease with which this noble gas diffuses from its parent rock into the interstices of the rock and then to a working area. Long-term exposure to moderate concentrations of Rn (3000 µµc per 1) and its short-lived alpha-ray emitting daughter products, RaA (Po218) and RaC (po214), has been found to result in an increased incidence of bronchial carcinomaa2 The acceptable limit of Rn daughter products in a mine atmosphere is presently set at a concentration of short-lived radon daughters which would be in equilibrium with 100 ppc of Rn per 1 of air. Ventilation of mines is conventionally accomplished by continuously diluting the mine air with fresh air brought in by fan or natural convection from above ground surface. The diluted air is allowed to vent freely to the atmosphere. This process does nothing to retard the rate at which gases (including Rn) diffuse into the mine from surrounding rock. It merely reduces the concentrations of these gases within the mine. It is suggested that in a sufficiently permeable rock environment a slight pressurization of the mine air may induce air flow from the mine into the interstices of rock surrounding the mine. The convective flow of comparatively fresh air will reduce the concentration and the concentration gradient of undesirable gases in the rock interstices adjacent to the mine. Radon will diffuse counter-current to this convective flow at a rate proportional to its concentration gradient. In time, a steady state of convection and counter diffusion will be established. The Rn flux into the mine will never be reduced to zero, and will only asymptotically approach zero as the overpressure (and hence the convective velocity of purging air) approaches infinity. During 1963 and 1964, an investigation into the effect which such applied pressures have upon the Rn characteristics of a mine atmosphere was conducted at the Kermac Nuclear Fuels Corp. uranium mines, Ambrosia Lake (near Grants), New Mexico.

Jan 1, 1967

By J. P. Walsted

Offgrade chromite concentrate, with a Cr-Fe ratio of 1.3 to 1.4 has been successfully smelted to produce useful ferroalloys. The Cr-Fe ratio is not improved, but the alloys can be used without a too drastic change in normal steel-mill practice. The ordinary high-carbon ferrochrome has been successfully produced by smelting under highly acid smelting conditions. An alloy containing 50 percent chromium was produced at a power consumption of 4,490 kw.-hr. per ton of alloy. Alloys containing 20 percent silicon were made by direct smelting chromite concentrate and silica.

Jan 1, 1956

By Edmond J. O’Donovan

South Bulga is a new longwall operation located in the Hunter Valley coal-mining region in Southeastern Australia. The mine’s objective is to achieve productivity levels significantly higher than the current industry average. From the day longwall production began, South Bulga’s output was below both budget and industry expectations, primarily because of the poor performance of the conveyor system. In the past, conveyor systems have been seen as an adjunct to the mine plan, not as an integral part. At past production levels, this approach may have been acceptable. In today’s mining operations, the conveyor system must be treated as integral and vital to the mining operation. The conveyor system is analogous to the vascular or circulatory system of the human body. Of itself, the system does not do anything, but if it is not functioning satisfactorily, the mine cannot operate.

Jan 1, 1996