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By Stan Tang, Yiming Sun, S. Amir Reza Beyabanaki, N. Sathi Sathialingam

The Kurve mixed-use development project including a 22-story tower at 2801 Sunset Place was constructed on a site consisting of a roughly rectangular-shaped lot at the intersection of Wilshire Boulevard and Hoover Street in Los Angeles. Two Metro Red Line tunnels, with depths of approximately 30 feet and 58 feet, respectively, cross below the building at distances of approximately 1 foot to over 63 feet from the site. This paper presents numerical modeling performed to evaluate the ground and tunnel behavior in response to building construction. Results of geotechnical instrumentation and monitoring undertaken during the building construction are also discussed.

Jun 13, 2023

By A. G. Journel

Accurate prediction of recoverable reserves are key to the development and planning of a mining operation. Recovery functions for tonnage, quantity of metal and ore grade are defined and two approaches for their estimation are proposed. The indicator kriging (IK) approach draws on the data rank orders, whereas the multi-gaussian (MG) approach relies on a grade multi-variate distribution hypothesis. Although based on different premises, both approaches yield remarkably similar--and accurate--estimates for recoverable reserves.

Jan 1, 1984

The knowledge of aggregate size under various chemical and hydrodynamic conditions is very important for selective agglomeration, flotation and water clarification processes. Traditionally, aggregate size measurements are conducted using an ex-situ technique or in a diluted suspension. In either case, the measurement occurs in an environment that does not resemble the actual conditions under which the aggregates are formed. In this study, an on-line scanning laser microscope has been used to study the coagula size of micronized coal suspensions as a function of pH, solids concentration and agitation intensity. A maximum aggregate size of 310 µ m was obtained under relatively quiescent conditions and at pH values near the iso-electric point (iep) of the coal. The aggregate size results compare well with the coagulation efficiency measurements obtained under the same pH conditions.

Jan 1, 1994

By S. Komar Kawatra, J. J. Carlson

"It is widely known that steel made from iron ore pellets high in phosphorus is brittle. Removal of phosphorus from iron ores such as hematite has proven to be difficult. The majority of research on phosphorus removal from hematite ores has been focused on flotation. The purpose of this study was to assess phosphorus distribution under current operations at an existing hematite concentrator and determine how efficient the plant is at removing phosphorus. Objectives included: (1) Perform a phosphorus balance at an operating plant to assess phosphorus distribution under current operations; (2) Determine phosphorus removal efficiency of each separating unit and (3) Perform a quantitative liberation analysis to determine max phosphorus removal by physical means. Liberation was quantitatively determined using wet high intensity magnetic separation (WHIMS) to separate iron ore from liberated apatite (and other nonmagnetic compounds).It was observed that 61.2% of the total phosphorus entering Plant F was rejected during current operations. The desliming process was the most efficient step at removing phosphorus (45.1% P removed), whereas the flotation step was much less effective (16.1% P removed). Liberation analyses indicated that the deslime thickener may have been more efficient at removing phosphorus than the flotation circuit due to the greater abundance of liberated phosphorus in the deslime thickener feed. The scavenger returns stream was identified as having a high concentration of phosphorus and a possible point of phosphorus removal. However, liberation analyses indicated that only 32.4% of the total phosphorus in the stream was liberated. Grinding the scavenger returns to 80% passing 5.2 µm increased the amount of liberated phosphorus in the stream to 70.4%."

Jan 1, 2014

By Luis R. Bittencourt

Research efforts have been made to characterize a refractory Brazilian bauxite ore composed basically of gibbsite, kaolinite and quartz. Detailed polished-section microprobe analysis of the unbroken ore has been used to describe the liberation characteristics and the association between mineral phases. The linear grade distributions for selected particle size fractions were determined by means? of a particular implementation of King's Random Fracture Model that uses the exponential model for the distribution of linear intercepts through both dispersed (kaolinite) and continuous (gibbsite) phases. The corresponding volumetric grade distributions were then determined by means of a constrained optimization technique for the solution of the transformation equation. Batch flotation experiments were carried out to determine the kinetics for particles of different sizes and the results correlated with the liberation spectrum for each size class.

Jan 1, 1991

By Donna Wallace

Past EPA groundwater monitoring programs required that contamination not leave the boundaries of a disposal facility. New regulations under the Resource Conservation and Recovery Act (RCRA) require that once hazardous waste constituents are detected beyond the limits of the disposal area, a program to define the rate and extent of contaminant migration must be instituted. Future regulations are likely to include even more stringent groundwater protection criteria. The implications of both the existing and probable future groundwater protection and monitoring requirements in terms of using geologic containment as a means of disposing of hazardous waste are explored in this paper.

Jan 1, 1981

By R. S. Hearon

The image of the open-pit miner in the eyes or the Environmentalist has never been very outstanding. The phosphate industry, whose history in Florida reaches back to the late 1800's, can-not be credited until recently with a large number or accomplishments in terms of protection or the environment to change this image. This lack of action was not deliberate or in opposition with the desires of the public. In the formative years, there was little or no public and the companies found it necessary to build towns to house their employees and their families, towns which remained in existence until the late 50's and early 60's or formed the core of present large communities. Neither these pioneers nor most subsequent resource developers considered themselves un-thinking spoilers, nor were they so regarded by their contemporaries. Instead, they acted in a manner consistent with their environmental circumstances and intellectual heritage. Early Americans did make mistakes in using the land but the mistakes became apparent only in the opinion of later generations. Over the past five to ten years, there has been a new self-awareness in the industry with regard to environmental responsibilities brought about, in part by a continuing onslaught of new regulations with jurisdiction over our activities. Part of the new regulations are aimed at industries as a whole while many, particularly state regulations, pertain specifically to the phosphate mining industry. Why all the new regulations? The reasons are encased in a complex web of activity but stem primarily from a new public awareness of its environment. More and more of our youth have become interested in the environmental science areas such as biology and ecology. The tremendous growth rate in both the population and industry has made personal issues out of subjects such as atmospheric inversions and water shortages which previously were abstract concepts. The State has grown from a population of 1,500,000 in 1930 to approximately 9,000,000 people today. This personal impact and general lack of knowledge on the part of the public concerning economics has resulted in big business no longer being held in awe, often in contempt and generally in suspicion where environmental concerns are encountered.

Jan 1, 1978

By W. J. Wuest

The U.S. Bureau of Mines (USBM) has recently developed a rock mass classification system for evaluating the structural competency of bedded roof strata; the Coal Mine Roof Rating, or CMRR. When compiled with the companion Lotus 1-2-3 spreadsheet, which is simple to learn and use, CMRR data are a useful tool with applications to longwall gate road pillar design, safety hazard mapping, and artificial roof support analysis. This paper demonstrates these applications under actual conditions found in current U.S. mining operations.

Jan 1, 1995

By Michael A. Werner

"A Yieldable Structure for Use in Areas of High Rock Stress & Deformation." Rock stress of up to 9000 psi have been recorded in the mines of the Coeur d'Alene Mining district. Associated with these large stresses are rock fractures and deformation. In order to maintain openings required for mining, large wood preparation structures are constructed to provide access to the work areas for men and materials. These wood raise preparation structures are costly to construct and maintain. Therefore a steel-foam concrete structure was designed and proposed for testing which would be less costly to construct, require no maintainence and maintain its structural integrity while allowing up to 53 inches of wall rock deformation.

Jan 1, 1984

By N. W. Johnson

Two analysis tools which have been applied to problems in industrial Flotation processses are the application of kinetics and detailed mineralogical or liberation data, both on a size-by-size basis. The paper describes practical examples of the application of kinetics to examination of the entrainment recovery mechanism, the retardation of valuable minerals at the commencement of flotation sections and the resolution of problems related to valuable species with reduced rate constants at the end of sections. Examples of the usefulness of size-by-size liberation data for monthly composite samples of products from a concentrator are also described.

Jan 1, 1985

The Colorado Joint Review Process (JRP), a bold step to expedite energy and mineral projects, is off and running. Blazing the trail is Amax Inc., which serve as guinea pig in JRP's development and is now test-flying the process at its Mt. Emmons molybdenum property in Gunnison County, CO. Although JRP is still in its infancy, the new permitting review process has drawn enthusiastic applause from across the resource spectrum: William K. Reilly, president of the Conservation Foundation, said JRP is "one of the most interesting projects I've seen" and called on environmentalists to monitor its progress "because it appears worthwhile." Stan Dempsey, vice president of Amax Inc., noted that of all the locales in which Amax operates, Colorado is "the only place where the complicated mine permitting scheme appears to work"-an achievement he attributes to JRP. Lynda Lee Brothers, the federal Energy Department's assistant deputy secretary of environment, reported that an extensive DOE search has not turned up "another single mechanism in all of government and private industry as good as JRP as a model for the proposed federal Energy Mobilization Board."

Jan 7, 1980

By J. A. Organiscak

This paper describes the research con-ducted on bit wear and respirable dust generation conducted by the US Bureau of Mines (USBM) and West Virginia University (WVU), a member of the Generic Technology Center on Respirable Dust. The USBM investigated wear, energy and dust characteristics of various conical bit designs when cutting rock. WVU studied the functional relationships between wear, cutting force, energy, and dust of one conical bit type when cutting coal. The objective of the USBM study was to identify qualitative bit selection guidelines for cut-ting rock; WVU's research objective was to determine optimum bit replacement guidelines. These research studies both found that bit geometry (a function of bit design and wear) influences energy consumption and dust generation. Bit selection and replacement recommendations are given.

Jan 1, 1995

By Andrzej M. Wala

A knowledge of the friction factor (K-factor) is necessary in planning and designing mine ventilation systems for least cost and highest effectiveness. The friction factor used must be accurate and reliable for correct estimation of airway resistances. At present, the friction factors are determined by using tables of published values. These values were established principally for metal-mine openings having small effective areas. This presents a problem to the ventilation design engineer whose responsibilities center around the design of effective ventilation systems for large room-and- pillar mechanized underground coal mines. Friction factors selected from these tables could be excessively conservative for large scale room-and- pillar operations. With only limited data on the K-factor (which are considerably site dependent) for Kentucky's coal mines and for all the above mentioned reasons, it was concluded that there is a need for field investigations to determine these values in-situ for existing mining conditions in Kentucky. The author describe the study carried out in ten coal mines located in eastern and western Kentucky and present the results of the investigation in both tabular and graphical form.

Jan 1, 1991

By R. M. Cox

Pneumatic coal loading and conveying systems provide alternative methods for the safe and efficient mining of the thin, high-grade coal seams found in the Southern Appalachians. Pneumatic systems eliminate most of the health and safety hazards associated with the operation of conventional mining and haulage equipment in small low-coal mines by removing powered mobile equipment from the mine. Ventilation is also improved by the coincidental removal of gas and respirable dust from the mine by the operation of the pneumatic loading and conveying system. Other significant advantages of pneumatic coal recovery systems are relative simplicity, operating flexibility, low capital cost, quiet operations, environmental benefits and ease of automation. The design considerations and field evaluations of experimental prototype pneumatic coal loading and conveying systems installed and operated in small thin-seam mines are presented in this paper. In addition, fundamental design criteria and recommendations for the installation and operation of a variety of pneumatic coal loading and conveying systems that offer alternative coal-recovery systems that alleviate the serious health and safety concerns of current small mine operations are proposed.

Jan 1, 2000

By John J. Schanz

The ideal entering freshman for the College of Mineral Industries possesses the necessary aptitude to complete successfully a difficult technical curriculum, has a highly developed intellectual curiosity and adequate preparation in basic mathematics, sciences, and English, is enthusiastic about pursuing a career in the mineral industries, and puts forth a good academic effort while attending Penn State. The present programs of the University?s Division of Counseling and the College of Mineral Industries are directed toward providing the College with students who will meet these requirements. At present, freshmen are admitted to the Pennsylvania State University without entrance examination if they are in the upper two-fifths of their high school classes. All Pennsylvania students in the lower three-fifths are required to take the University Aptitude Test and all out-of-state students the College Entrance Board Examinations. Such students are admitted only if they score sufficiently high on either test to indicate the ability to do satisfactorily the work of University students. Only to this extent, are native intelligence and areas of greatest aptitude known for the Freshman prior to admission, and they are, therefore, largely beyond the control of either the Division of Counseling or the College of Mineral Industries. Because all freshmen, with exceptions that are numerically minor, are required to select a curriculum before admission to Penn State, each student who presents himself for required counseling during the summer, prior to his first semester, has already made a choice of his course of study. In many instances, such choices have been made without a rational and serious consideration of the student?s abilities and interests. Through tests given between the date of admission and the date of the counselling interview, it is possible to measure these characteristics and for the Division of Counselling to advise the student of his chances of success in his chosen curriculum. If he is qualified for the curriculum he has selected, Counselling Service goes on to direct the student?s attention to those other curriculums which are in the same general area as the one he has chosen and which will also challenge his abilities and correspond to his interests, Through this counselling, the curriculums of the College of Mineral Industries, which are often less well known to high school students than others for which they are no more qualified by ability or interest, are brought to the attention of the incoming freshman.

Jan 1, 1959

By Jean-François Boucher, Ernest K. Yanful, Mei Lin Shelp, Lionel J. J. Catalan

Shallow water covers for preventing acid production in tailings are based on the principle of minimizing oxygen availability. Resuspension of material from the tailings bed may result in increased oxidation and metal releases since dissolved oxygen is at near saturation levels in the water cover. Resuspension can be caused by waves and currents strong enough to mobilize the surface of the tailings bed. Tailings resuspension was measured with sediment traps in the Upper Cell of the Heath Steele site near Mirarnichi, New Brunswick Canada. Although significant amounts of resuspended tailings were collected in all traps, analysis of resuspended solids and bed tailings suggests that for the observed wind conditions resuspension did not occur at locations where the water cover depth was greater or equal to 1.0 m. Currents were likely responsible for the transport of resuspended tailings from shallower areas to locations where the water cover was deeper than 1.0 m.

Jan 1, 2000

By Alex Stewart

Most iron bearing ores treated by the R=N Direct Reduction Process yield products lower in phosphorus than the initial ores. The sulfur is also removed and generally is in the range of 0.02 to 0.05 percent in the final R=N product, independent of the sulfur content of both the ore and carbon fuel used. The mechanism and thermodynamic justification of the principal reactions leading to the removal of both phosphorus and sulfur and the control of sulfur in the iron concentrate produced are discussed and supported by the results of laboratory experiments. In substantially all iron ores (containing up to 4% sulfur as sulfate) and solid carbon fuels (containing sulfur from 1 to 8%) tested, the rejection of sulfur has been in the order of 90-95%, with not more than 0.02 0.05% sulfur in the final metallic iron product. With respect to phosphorus-bearing iron ores ranging up to 0.70% P205, the rejection to tailings has been in the order of 70-95%, resulting in not more than 0.03 - 0.07% phosphorus in the final product.

Jan 1, 1958

By Peter Zhang, Daniel Su, Berk Tulu, Bo Hyun Kim, Zoheir Khademian

Over 2,000 shale gas wells have been drilled in the Pittsburgh Seam longwall reserves. As longwall panels are laid out, some of these shale gas wells must be located in longwall chain pillars. With longwall mining on both sides and the constraint of chain pillar size, gas well in chain pillars are subjected to longwall-induced ground movements and stresses, which could induce deformations in gas well casings Casing deformations are associated with several factors such as overburden geology, surface topography, setback distance, and casing construction. Overburden geology is one important factor that largely determines the locations and levels of deformations in gas well casings Previous NIOSH gas well research has found that casing deformations above the coal seam horizon are smaller under deep cover than unde shallow cover and that casing deformations could occur at the coal seam horizon under deep cover. Recent mine-by cases have provided more insights into the locations and amount of longwall-induced casing deformations as well as the potential occurrence of a large casing deformation at the coal seam horizon. This paper presents three recent mine-by cases with shale gas wells in the chain pillars between two adjacent longwall panels under different overburden depths. Casing deformations were measured by multi-finger caliper surveys and predicted with numerical modeling. With the established numerical model, the effect of overburden depth was further analyzed to investigate the potential occurrence of a large casing deformation at the coal seam horizon under deep cover. These mine-by cases not only provide a general demonstration of how overburden depths can affect longwall-induced stresses and deformations but also give a good indication about the level of casing deformations that could occur under different overburden depths. The study concludes that (1) casing deformations reduce with increase of overburden depths at the gas well; (2) a cementing alternative with production casing uncemented is an effective means to eliminate production casing deformations; and (3) large plastic casing deformation could occur in the production casing at the coat seam horizon under deep cover. The experience and knowledge gained from these mine-by cases would help longwall operators and gaza companies to take appropriate measures to minimize the influence of longwall mining in shale gas wells in chain pillars.

Jun 25, 2024

By K. R. Miller

Thunder Basin Coal Company has two mines located in the southern portion of the Powder River Basin. 60-90 km southeast of Gillette, Wyoming. The mines are principally located on federal coal leases acquired in the late-1960's. Development plans for the Black Thunder Mine focused on dragline stripping, but environmental considerations during the mid-1970's made truck-shovel stripping the method of choice when the mine opened in 1976. In 1981, the Coal Creek Mine opened as the first dragline mine in the Gillette area of the Powder River Basin. The regional terrain is flat-lying with occasional clinker-capped hills. The mines are located on the Wasatch and Fort Union Formation contact. The coals are Paleocene in age and the deposits are structurally simple, dipping gently to the west. The seams are thick and are classified as sub-bituminous-C. The Black Thunder Mine, with its 21 m thick seam, is strategically located in the center of the highest heat value mining area of the southern Powder River Basin.

Jan 1, 1993

By Donald P. Moore

During April 1967 a Frasch sulfur mine was placed in operation near Fort Stockton, Pecos County, in West Texas. This was the first Frasch mine to recover native sulfur from a deposit not associated with the caprock of a salt dome. Since 1967 two additional mines have been opened in west Texas, another one near the first at Fort Stockton and a third one near Orla in Culberson County (Figure 2). Recoverable reserves at the Culberson County mine are estimated to be 57,000,000 long tons of native sulfur (Zimmerman and Thomas, 1969). Total recoverable reserves at the three mines probably exceed 60,000,000 long tons, Studies of the geochemical cycle of native sulfur mineralization in test Texas indicate an origin similar to the deposits on salt domes although the geologic framework is different. A comparison of the geologic setting of the west Texas deposits with the deposits in the Union of Soviet Socialist Republics as reported in the literature, reveals many similarities. ACKNOWLEDGEMENTS The writer wishes to express his appreciation to Cities Service Minerals Corporation for support throughout this study. Special thanks are due Dr. Chris Riecken and Mr. Dave Hardy for their

Jan 1, 1971