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By Whitmell J. Smithwick

Lime is one of the most extensively used chemicals in industry. Other than sulfuric acid, it is used in greater quantities than any other man-made industrial chemical. In 1974 there were 20,368,000 tons of lime used in the United States, which amounts to approximately 190 pounds for each man, woman and child in our nation. Lime also is perhaps the most diversely used of any industrial chemical. It is used in such areas as pharmaceutical, chemical, steel making, glass making, production of copper and aluminum, sugar refining, agriculture, construction, ecological endeavors, potable water treatment and sanitation. Figure I lists the major uses of lime for 1974, which is the latest year for which this data is available. The impact of the use of lime for ecological reasons did not show up to any appreciable extent in 1974, but we expect this to be a significant factor within the next few years. Fortunately, in the United States and also in most of the world, there are many deposits of high quality limestone available for the production of hood quality lime. For this discussion, we will assure that a limestone of a suitable quality and size consist will be available in a storage bin or stockpile near the kiln. Quality requirements for the lime product will be covered. We also will give a brief description of the three most popular types of lime calcining systems, how they function, and expected lime product quality from each of these. Commercial fuels and major accessory equipment will be discussed briefly.

Jan 1, 1976

By Bo Hyun Kim, Mark K. Larson

Researchers at the National Institute for Occupational Safety and Health have tested the finite element code, UT3PC, with LaModel to evaluate their results using know case studies. The purpose of the testing was to demonstrate the usefulness and limitations of these programs in evaluating mine layout design. Both of these software packages are simple to use and free for public download. Their use by mine engineers, along with other tools, such as empirical methods, can enhance the assessment of a mine layout design. LaModel can model mining layout on a mine scale or, at least, on a multiple-panel scale. However, this software has limitations in calibrating to conditions at many coal mines in the western United States. The UT3PC software models smaller parts of a mine and is used to evaluate the design of pillars, shafts, or drifts; but the software calculates all components of the stress tensor and provides stresses, displacements, and safety factors throughout the model volume. The two codes are used to evaluate design of one known case, and UT3PC is used to evaluate another case. The results and approaches demonstrated in the testing are intended to aid mine engineers in evaluating site-specific problems and to show that these tools can provide useful information to the mine engineer in evaluating mine layout design.

Jul 1, 2023

By P. M. Hawley

In April 1975 Kaiser Steel Corporation and the United States' Department of Energy entered into a cost-sharing agreement for the demonstration of shield-type longwall supports on three consecutive longwall panels at Kaiser's York Canyon' Mine in New Mexico. Under this agreement the Department of Energy supplied 117 Hemscheidt 320 HSL caliper-type shield supports and hydraulic pumps for the duration of the demonstration. The purpose of the demonstration was to educate the U.S. coal mining industry as to the benefits in production, productivity, health and safety, and increased coal extraction afforded by shield-type longwall mining systems and to provide the industry with a working model. A detailed description of this demonstration is given in U.S. Department of Energy Publication No. DOE/ET/12530-T1, entitled "Demonstration of Shield-Type Longwall Supports at York Canyon Mine of Kaiser Steel Corporation," hereafter referred to as the York Canyon Report.

Jan 1, 1984

By M. Springett

Organization of teams for rapid and effective evaluation of international mining properties requires special considerations beyond those needed for domestic activities. Experience, technical ability, a sense of perspective, humor and self-discipline are vital characteristics to look for in the selection of individuals for forming an efficient and productive team.

Jan 1, 1994

By John S. Harper

Can the mining industry in the United States accept the change and challenge of the "Now Generation" of entirely new high-performance automated transportation systems? Good Question! While there has been some revolutionary new thinking and product testing in mining, none has taken place in transportation of ore and waste. With one notable exception - DASHAVEYOR - not a single really new and 'unconventional' system has even been tried on a small scale in the hardrock mines in our country. Admittedly, U.S. equipment manufacturers share the responsibility for the slow progress in mine transportation systems in our country, since they have provided very litte leadership in design innovation or education. First, let me give you my definition of what is meant by the term "Advanced Transportation Systems". Then I will describe and compare such systems, emphasizing the strong and weak features of each as they apply to vertical and horizontal haulage. I will conclude by establishing the principal requirements for implementation of these types of systems in the mining industry in the United States.

Jan 1, 1969

By Rex T. Ellington

The fluidized bed is an effective method for investigating retorting phenomena and possibly a commercial means of retorting oil shale. Both were examined by Sinclair Oil Corp. (now part of Atlantic Richfield Co.) in the period 1.965 to 1968. The results of the work show that presence of an oxidizing environment during retorting results in loss of oil yield which indicates that vapor phase oil burns in preference to combustion of coke on spent shale. This has implications for several types of retorts. Correlation of the results of this work with that of other investigators shows that the partial pressure of retorting products in contact with oil shale during retorting has an effect on yield. Consideration of hardware indicates that there are several possibilities for commercial embodiment. As a companion to shaft-type retorts the fluidized bed could have good potential. Realistic assessment of costs suggests that further development may have to await commercialization of another process. The existence of a plant in which to test prototype size would markedly reduce such development costs. Results Preliminary development work with the apparatus was carried out using a fluidized bed of sand, as explained later, with the entire system brought up to temperature and flows stabilized. The shale was injected rapidly in a slug (batch) which had small mass compared to that of the high temperature system to make the reaction approach isothermality with reasonable approximation of instantaneous preheating. Typically, the temperature in the center of the bed dropped from 900°F to 600°F one minute after batch addition. It returned to 750' within three minutes and 900° within seven minutes. Obviously, the bed was quenched but it recovered rapidly. Average bed temperatures of 700' to 1020°F were examined to compare the effect of temperature with published results. Yields In the 700°F range were only 10 to 15%, of Fischer Assay (FA). Above about 950'F, oil yields decreased and gas yields increased. Nitrogen was used first as the fluidizing gas to provide a chemically inert medium. Incept for an insignificant dip at 895"F, Figure 1, oil yield was not affected by retorting temperature in the 800° to 900' range as long as residence time was adequate (16 minutes). At 925°F, the oil yield was some 103% FA. With further increase in temperature, the yield decreased to 86% FA at 1015°F. There is no increase in carbon on spent shale, the lost oil goes to Increased gas make.

Jan 1, 1972

By John S. Cummings

Although there are many geologic situations which might be discussed at a session such as this, as I considered the problem, it became apparent to me that I should discuss a situation which has been of concern to me, and should be of concern to the geologic community. As a result, the questions which I will pose, and the criticisms, have not been arrived at quickly or easily, but have accumulated through time, to the point where I feel discussion is necessary. Very briefly let me say that my criticism of geologic mapping, of conclusions reached, and objectives or lack of such, results from my association with many areas where such studies have been completed, and resultingly my inability to comprehend the system of evidence or logic which supports extensive age-formational designations. The heart of the problem is that many conclusions resulting in geologic designations are based on weak or non-existent evidence, and such should be catagorized as hypotheses. Although the geologic community as a group does not approve or disapprove of such designations, it is evident that many or most of such designations attain a "status", and arc accepted as more or less valid statements. As will be shown, the amount of specific lithologic data provided in some quadrangle mapping projects is exceedingly slim. However, of concern herein is that the type of information presented at any stage is sufficient to warrant conclusions drawn. To see the magnitude of the problem, it is probably necessary to review some basic fundamentals upon which our geologic systems are established. The United States Geological Survey has defined a "formation" as the broad unit of geologic mapping consisting of a large and persistent stratum of one kind of rock. Obviously such a designation allows that a formation could be considered "time variant" in a horizontal as well as in a vertical context. However, other definitions enable a formation to mean units

Jan 1, 1972

By Taghi Sherizadeh, Kutay E. Karadeniz, Dogukan Guner, Samuel Nowak

Seals and build-in-place (BIP) refuge alternatives (RAs) are two main underground structures to isolate an area from the active working zones with different purposes. While seals are used to prevent methane gas that seeps from coal seams and blast pressures from a possible detonation of the contained gas, RAs are used to provide a safe haven for miners who are unable to escape their working locations after an accident like an explosion or fire. The recommended BIP RA designs can be similar to seals constructed with steel-reinforced concrete. Both seal and BIP RA are constructed in different locations of the mines for a period of time, exposed to a certain convergence due to stress redistribution which can change their responses during an explosion. In this study, a steel-reinforced concrete wall to be used in such applications is simulated to examine the structural performance during an explosion for a coal mine model with different strata conditions using dynamic analysis by a 3D distinct element method (DEM) code. The main purpose of this study is to reveal any possible effects or trends on the wall deformation with changes in strata conditions by implementing different combinations of roof, seam, and floor material properties. The model is calibrated by the experiment conducted on a steel-reinforced concrete wall by the NIOSH researchers in the Lake Lynn Experimental Mine. The results show that strong adjacent rock and coal units are the least favorable condition for the survival of the wall subjected to a simulated explosion pressure. The results indicate that changes in the roof and seam conditions can have dramatic effects on the deformation characteristics of the wall when compared to the floor conditions. The results of this study might be enlightening for future BIP RA and seal applications.

Feb 8, 2023

By E. S. Cheney

The sandstone-type uranium deposits of the Gas Hills occur in the arkosic, lower Eocene Wind River formation on the southern edge of the Wind River Basin. The d S34 values of pyrite cement associated with uranium mineralization are-significantly lighter than values for syngenetic-diagenetic pyrite nodules, therefore the H2S responsible for the precipitation of the epigenetic pyrite and uraninite was produced [t]epigenetically. These values are much lighter than the values of H2S from neighboring oil fields. The presence of biogenic pyrite in meta-igneous Precambrian cobbles indicates that these cobbles are not remnants of former; vein-type uranium deposits.

Jan 1, 1964

By A. G. Provost

On April 3, 1981, Harrison Western Corporation was awarded a contract by Amax Alloy - A Division of Amax Inc., to sink the Henderson #5 ventilation shaft. The project was located on the Henderson Mine site 88 kilometers west of Denver near the town of Empire, Colorado (Figure I). The Henderson No. 5 Shaft, located in an Alpine environment at an elevation of 3145 meters, was a 9.8 meter diameter concrete lined shaft with a total depth of 793 meters. Work started and continued with Harrison Western employees until January 15, 1982. At that time, Amax made the decision to continue the shaft-sinking with their own labor, and with Harrison Western providing supervision under a management service contract. Shaft sinking continued under this arrangement to October 1, 1982, at which time Amax put the Henderson No. 5 project on standby status until further notice.

Jan 1, 1986

By Martin B. Zimmerman

It is becoming evident that traditional methods of econometric analysis are inadequate in estimating-the long-run supply of minerals. Econometrics is limited to extracting estimates from observations of the theory predicts that the least cost deposits will be exploited first.1 The estimation of parameters from past data then must lead to biased projections of the future. Mining conditions in the future will be worse than in the past and it is the impact of the future conditions on cost that we need to know. In this paper we present a methodology for dealing with this problem. We estimate a "cumulative cost" function that yields the long-run marginal cost of mining as a function of cumulative output produced over time.2 This is relatively easy to do for coal mining in the United States where exploration for new deposits is not a major factor in supply. The first step of the procedure relates cost to the rate of output and to the geological conditions of the mine. The second step combines geological information on remaining deposits with the cost function to yield the cumulative cost function. A central theme of both these steps is the interaction of economics with geology. The best deposits are selected first and in each step of the estimation allowance must be made for this fact. The problem of depletion is part of the general problem of structural change. The change through depletion in the nature of the exploitable mineral stock is only one factor that calls for an analysis sensitive to the changing circumstances of the industry. The factors impinging most heavily on the coal industry today are the strict environmental regulations legislated

Jan 1, 1977

The last decade has seen the use of powerful computerized Mine-Wide Monitoring (MWM) systems for detecting hazardous conditions in underground coal mines. Recently, the U.S. Bureau of Mines and Jim Walter Resources, Inc. (JWR) expanded the scope of MWM system to include ground control. Single-point extensometers were installed in each of 30 intersections along a tailgate entry. These instruments monitored the rate of roof sag, a sensitive indicator of roof instability. Data were collected by the mine's own computerized MWM system. The paper describes the successful integration of ground control instruments into MWM, the data reduction procedures, and the identification of several hazardous areas.

Jan 1, 1994

By Adam Bedell, Paul Derby, Brad Crenshaw

Modified contact grouting was introduced almost 15 years ago as a methodology combining traditional contact grouting and consolidation grouting to address groundwater infiltration into hard rock tunnels that utilize cast-in-place concrete as permanent tunnel support. This process has been used on additional tunnels (since initially presented) as a measure to mitigate both groundwater infiltration and exfiltration. During this time, self-sealing grouts have been developed and have been added to the process to further reduce groundwater infiltration that occurs through cracks and discontinuities within the concrete liner itself. This modification is presented and additional results from the grouting process are discussed.

Jun 13, 2021

By J. A. Wallace

U. S. Steel's coal mining research activities are directed toward providing new or improved hardware and techniques to increase productivity or reduce cost. Because more than 80 percent of U. S. Steel's coal production is obtained from continuous miner sections, most of our research efforts are focused upon that mining system. Current and historical time study data show that our continuous miners only operate about 30 percent of the available face time. This limited equipment utilization is the result of the delays or interferences imposed by the non-coal-cutting phases of the continuous mining cycle. The most time consuming of these delays are: waiting-on-roof-support, tramming between alternate work locations, waiting-on-haulage-capacity, and in some mines waiting for excessive methane concentrations to clear. Because waiting on roof support is our most time consuming delay, several programs are underway simultaneously to address this problem. In one of these we are developing a patented microprocessor-based control method and apparatus to improve roof drilling performance. This increase is attained by using the microprocessor to adjust electrohydraulic valves which control drill thrust and rotation speed. The microprocessor is designed to continuously search for an optimum combination of thrust and drill rpm to maximize penetration rate at all times.

Jan 1, 1979

By J. Weinstein

New erosion, corrosion resistant metal, ceramic, and polymer composite technologies are being developed and marketed by Alanx Products L.P. for use in hydrocyclones, pumps, valves, and other applications in mining and minerals processing. This paper will present an overview of the ceramic/metal composite material system and properties developed, which include excellent erosion/ corrosion resistance. Wear data will be shown from a variety of laboratory tests in dry and wet conditions, in aqueous neutral and corrosive environments. Comparisons will be made with a variety of competitive materials currently used in the industries sited. Data will also be presented on field tests with pumps and hydrocyclones in hard rock mining and other abrasive/corrosive environments. Field data from North and South America, as well as Australian mining applications will be highlighted.

Jan 1, 1992

By Otto E. Zwanzig

You may think long before this talk has been completed that the speaker is belaboring the obvious. Please let me put to rest here and now any doubt which you may have in this regard by assuring you that is precisely my intent, and for a very specific reason. We all profess to know and recognize the obvious, but I am impressed increasingly how often we forget or fail to act upon the obvious. Shortly after starting my first job upon graduation from college, I was asked by my boss to participate in a course on practical communications, particularly as applied to conveying proposals effectively to the client -- be he customer or company president. The concept or philosophy underlying this program was so simple and obvious that in my youthful brashness I saw only a gross waste by the company of e good, solid $1930 in compelling me to take the course. The sequel to this experience occurred about five yews ago when I was directing a 300-man marketing group. At that time I enrolled a dozen of my department heads, and subsequently about a hundred other personnel, in the contemporary version of that sane program. Why? -- because they all knew the obvious, but I could see how imperfectly they were implementing it. Truly, a wide chasm exists all too often in our beliefs on the one hand and our practices on the other.

Jan 1, 1962

By Alejandro Sanz, Juan Luis Magro, David Mazeyrie

The Hampton Roads Bridge-Tunnel Expansion Project (HRBT), initiated by the Virginia Department of Transportation (VDOT), will add two new 1.5-mile TBM bored tunnels to the two existing immersed-tube tunnels between artificial islands, part of the connection between Norfolk and Hampton under the Hampton Roads Harbor in Virginia, USA. The new bored tunnels will be built by Hampton Roads Connector Partners (HRCP), a joint venture of Dragados USA, Vinci Construction, Flatiron Constructors and Dodin Campenon Bernard. This paper covers technical discussions that led HRCP to select a Variable Density TBM to address the challenges of this tunnel project, including but not limited to (i) the diameter of the bore: a 46 feet (14.04 m) diameter machine that constitutes the second-largest TBM ever used in the United States; (ii) shallow ground-cover under the water table; (iii) challenging and varying geology along the alignment, with mixed-face conditions and different types of ground modification zones; and (iv) the high TBM operating pressures required—all these and other challenges in a sensitive marine environment.

Jun 13, 2021

By William Gleason

"What will the mine of the future look like? Will it resemble the current operations that supply the world with the products it needs to function, or will it be something totally different? How will the demands from the communities that are most affected by mining operations shape the mine of the future? How will technology and innovation be used to help miners reach deposits that are getting harder to access, and what are the dangers of this new world? Who will work at the mine of the future, and what will that work look like?These are questions that do not yet have definitive answers, but they are questions that need to be asked for the mining industry to move into a future that is as filled with uncertainty and challenge as it is with promise and opportunity.On Feb. 16, the 2015 SME Annual Conference and Expo and the 117th CMA National Western Mining Association conference began with a keynote address, "The mine of the future: Forecasting opportunities and challenges for the global mining industry." Panelists from five sectors of the mining industry participated in the session, which was followed by the conference and expo, that in large part, were also trying to answer the question of what the mine of the future will look like.In coming months, Mining Engineering will continue the discussions and answer some of the questions submitted by members of the 2,000-person audience during the keynote address in a monthly feature called, "Predicting the Mine of the Future," and in Thought Leaders Podcasts with the panelists and other industry experts."

Jan 1, 2014

By O. K. Olawale, G. O. Edaogbogun, B. N. Ben‑Festus, F. Ben, F. R. Amodu

The environmental and health implications of artisanal gold mining activities at mining sites across Nigeria have rekindled research interest. This study aimed to assess the scalability of naturally occurring radioactive materials in gold mining sites in Iperindo, Nigeria. Soil samples were collected from three different mining sites and control locations and analyzed for natural radionuclides, mainly 238U, 232Th, and 40K, using gamma spectrometry having a sodium iodide detector. The average activity concentration values of 61.55 ± 3.71, 72.65 ± 4.45, and 1134.99 ± 38.12 Bqkg− 1 obtained from within the mining sites for 238U, 232Th, and 40K, respectively, were above the world permissible values of 33.0 Bqkg− 1 for 238U, 45.0 Bqkg− 1 for 232Th, and 420.0 Bqkg− 1 for 40K. The average activity concentration values of 15.26 ± 3.19, 21.46 ± 4.27, 381.04 ± 23.36 Bqkg− 1 estimated for 238U, 232Th, and 40K, respectively, for the control location were, however, lower than the global permissible values. The study also evaluated other radiological parameters such as radium equivalent, dose rate, annual effective dose rate, internal and external hazard indices, and alpha and gamma indices. The obtained values were 252.83 Bqkg− 1, 119.98 nGyh− 1, 147.15 mSvy− 1, 0.85 Bqkg− 1, 0.68 Bqkg− 1, 0.31 Bqkg− 1, and 1.89 Bqkg− 1 respectively. Except for radium equivalent, external and internal hazard risks, and alpha index, which were significantly lower than the recommended threshold, all other radiological parameters were higher than the recommended global limits. Moderate data reproducibility and a p-value of 0.000574 further reinforced the robustness and reliability of the results obtained in this study.

Feb 22, 2024

By Fabrizio Fara

The Ship Canal Water Quality Project (SCWQP) includes a 2.7-mile long, 18'-10" internal diameter tunnel which is located inWest Seattle. Tunneling in urban areas and soft ground conditions (Till and Till-like soils in Seattle) is associated with the risk of settlements, especially in presence of groundwater above the alignment. The Designer foresaw the use of soil improvement (jet grouting) outside of the launch shaft to mitigate the risk of flowing ground and to provide a redundant sealing. The Contractor proposed and ultimately successfully executed a different approach by using a “Steel Bell System” or Pressurized Can as described in this paper.

Jun 13, 2023