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By Raja P. Upadhyay

An evaluation of the economics of mining the deep, thick oil shale deposits of the central portion of the Piceance Creek basin, Colorado, U.S.A. is presented in this paper. For the analysis, a modified large scale underground mining system developed by Cameron Engineers, Inc. and the Gas Combustion retorting process developed by the U.S. Bureau of Mines were used to determine capital investment and annual operating costs. A modified risk analysis computer program was then used to calculate DCFROI’s for various grades of oil shale and selling prices of partially refined shale oil. Sensitivity analyses were performed to quantify the affect of bonus bid payments, operating costs, capital investment, and all costs on DCFROI. In addition, a probabilistic evaluation was made to determine the risk involved in obtaining desired rates of return. Results of the economic evaluation indicate that for current selling prices of crude oil a high risk is involved in obtaining a DCFROI of 15%, unless only higher grades of oil shale are mined. However, mining only the higher grade oil shales, 125 l/mt (30 gpt) and above, would effectively reduce the potentially mineable resources by 90%. Risk can also be reduced through higher selling prices of shale oil. Sensitivity analyses indicate that the capital investment has a three times greater effect on required selling price than total operating costs.

Jan 1, 1977

By Tim Ross

J. M. Huber Corporation's Quincey Mine. an underground limestone mine located near Quincy. Illinois, has operated successfully and safely for many years utilizing roof bolts on a very limited basis. Over the years, the mine had experienced several rool falls that did not result in injury to personnel. Nearly all of the roof falls were limited to the first 2 feet of the massive limestone roof. Investigation of the falls indicated the major contributing factor to these roof falls was a randomly occuring thin. horizontal clay layer in the immediate roof. Over time, separation would occur at the clay layer. causing the root to sag. and eventually causing the root to fail. J. M. Huber Corporation contracted with NSA Engineering. Inc. to assist in a study to determine the effectiveness of Ground Penetrating Radar (GPR ) for locating these potential root fall areas so that mitigating action could he taken prior to roof failure. Multiple tests were conducted in areas of known roof conditions. GPR accurately predicted the existence or absence of root separation up to 1.5 meters into the immediate roof for 100 % of the known lest site conditions. As a consequence of this successful studs, J. M. Huber Corporation has used GPR to evaluate roof conditions at both its Quince and Marble Hill Mines.

Jan 1, 2002

By Reid A. F

Since early 1971 Western Titanium N.L. has been operating an ilmenite upgrading plant on a commercial basis at Capel, Western Australia. In their process ilmenite is pre- oxidized, then reduced in a rotary kiln to a mixture of metallic iron and titanium oxides. The iron is leached out by accelerated rusting in aerated water, leaving a product with titanium content, expressed as Ti02, of about 92%. Samples from different stages of the up- grading process, representing operations over the last two years, have been studied in detail by X-ray diffraction methods, and the sequences of phases and reactions occurring have been determined. Quantitative X-ray studies showed the ilmenite feed materials to consist of a mixture of ilmenite and pseudo- rutile. Pre-oxidation of the ilmenite at =1000¦C leads to the formation of rutile plus a Fe2TiO5-FeTi205-Mn2TiO5 solid solution. The final reduction product consisted of a mixture of metallic iron, reduced rutile and a FeTi05-MnTi205-Ti305 solid solution. The relative amounts of these reduction products were very sensitive to the initial concentra- tions of the minor constituents manganese and magnesium. The effects of variation of ilmenite feed rate, reducing atmosphere,- reduction temperature and controlled addition of magnesium were also studied.

Jan 1, 1973

By A Struminski

The principles of occupational risk evaluation resulting from the improper ventilation of the underground mines were presented. It was shown that the risk level implies the appropriate planning and usage of prevention methods. That approach is fundamental in the ventilation, fire and climate safety management in the copper ore mines. The paper uses the adequately modified Risk Score method.

Jan 1, 2003

By Richards J. W.

J.W. RICHARDS, South Bethlehem, Pa. (communication to the Secretary?).-Mr. Howland's paper, data and conclusions have interested me intensely, and have led me to study carefully the record-of his 26 furnaces therein given. Mr. Howland is undoubtedly right in his conclusion that when expressing the amount of carbon burned at the tuyères in percentage of the total

Jan 1, 1917

By B. G. D. Smart

An understanding of the nature of yield zones surrounding coal mine excavations is fundamental to the design of mine support systems. Various methods have been designed for investigation of underground rock masses and an extensometric technique, the Magnetic Rod Extensometer, has been developed to overcome inherent design limitations in existing equipment of this type. This paper refers to the prototype form of the extensometer and details changes designed to overcome a variety of drawbacks indicated by routine use of the equipment. The principal change has been one of manual to computerised data acquisition and presentation in the laboratory phase of the system. This has dramatically reduced the time taken to process underground measurements and produce numerical and graphical results. The revised Magnetic Rod Extensometer represents an integrated instrumentation system that combines speed and accuracy in all areas of data handling.

Jan 1, 1984

By Takayuki Sakai, Takefumi Takuma, Lee Roesner

"70-foot deep rectangular-shaped bulkheads were built with sheet piles as launching and receiving shafts for a pipe jacking operation for new underground waterlines in a densely populated section of Los Angeles, California. The Press-in Piling Method was specified to drive 95-foot long sheets (a record for the method) to form the bulkheads for the Los Angeles Department of Water and Power’s LA-29 (DWP) Connection Modification and Pipe Jacking. The piling was chosen because of its very low noise and practically vibration-free nature since the site is surrounded by houses, an apartment complex, and existing water lines. The out front areas of the bulkheads were grouted to let the TBM go through without major ground water leaks. Hydrophilic foam grout was also injected in addition to welding steel scab plates on the inside to seal them to achieve sufficient watertightness behind a few split interlocks. BACKGROUND This project was located in the Crescent Heights area of Los Angeles which is a few miles south of Beverly Hills. The project represents the completion of the last phase of the Stone Hollywood Trunk Line. This was an 8-mile long water trunk line that averaged 60 inches in diameter and was built to improve the reliability of the DWP’s major water system. This section of the project involved driving 2 deep shafts to allow for the installation of a 350-foot-long 72-inch steel casing using microtunneling construction. See Figure 1 for the shaft locations and the tunnel alignment. The challenge for the project was that this water line would have to pass beneath the Hollyhills buried box drain (15 feet high by 20 feet wide). Further complicating the construction was the soils beneath the drain. The DWP chose to drive the tunnel at a depth of approximately 65 feet to ensure that the ground conditions were uniform and suitable for the microtunneling equipment. There were two previous attempts to construct this work which failed because of poor ground conditions and very high water levels. This third attempt was critical because the DWP could not afford to have another failure due to the fallout with the residents being impacted by the project."

Jan 1, 2016

By Pier Paolo Manca

The investigated area lies close to a large town and covers an area of about lkm2. The mine was worked at depths ranging from 5 to 100 meters but mining operations actually ceased some 50 years ago. There are seven coal seams, each one to two meters thick, overlain by sedimentary rocks in a strongly faulted area. Different kinds of subsidence have occurred, crown holes, shallow depressions and hummocky ground. The results of rock mechanical characterisation (RMR method) in the area have been used to define three different types of numerical model (FLAC 2D). A large numbers of simulations has been performed to solve three different problems at three different scales: to determine the, mechanical properties of the roof rock and overburden involved in the subsidence process, to assess the crown hole subsidence potential and to define the properties of the beam foundations.

Jan 1, 1999

By R. Marrill

Mining is a complex and intensive industry. Extracting raw material with different shapes, sizes, chemistry from the earth?s crust and transform them into a standardized and high quality final product is a big processing challenge - which involves energy and control on large scales. Not only is the physical work challenging, the mining industry today is facing unprecedented challenges: Decline of mineral grade and reserves, cost escalation for new developments and modernization, regulations, safety, lack of skilled people, and market uncertainty are the new constant. It is clear that process control and management of electrical power will be of increasing importance to the recovery rates the mine will achieve. The objective of this paper is to provide a quick vision about future trends and evolutions in technology related to these fields and their impact on Electrical Safety and Control of the mineral recovery. The paper will cover trends in safety, energy management and efficiency, communications of data, control room evolutions, plant integration, other control technologies, and we will examine how these technologies provide information and the benefits of aligned reporting systems to address current industry challenges. More than just the trends or breakthrough concepts, current technologies are available today that can be applied in the mineral recovery operations now to help overcome anticipated future challenges will be presented later in this document. Finally, a brief discussion to look at some real tools to help make real time changes to the process while maximizing recovery and optimizing cost.

Feb 27, 2013

By Carla A. Kertis, Alan A. Campoli, Claude A. Goode

This Bureau of Mines study was conducted to obtain a better understanding of the coal mine bump problem and its effect on underground coal mining in the Eastern United States. To accomplish this, information was collected on the geologic conditions, mining techniques, and engineering parameters at five bump-prone mines. Two geologic conditions have been found to cause the occurrence of bumps in the Eastern United States: (1) relatively thick overburden and (2) extremely rigid strata occurring immediately above and below the mine coalbed. Additionally, the probability of bump occurrence is increased by certain mining practices that concentrate stresses during retreat mining, in areas where geologic conditions are conducive to bumps. Mining plans that permit the development of pillar line points or long roof spans that project over gob areas should be avoided because these features may contribute to the occurrence of bumps.

Jan 1, 1987

By Padmavathi V. Sagi

In this paper, effect of cyclic loading on the behavior of a long, flexible, unrestrained vertical pile loaded laterally in soft clay is examined. For cyclic loading, the analysis is carried out using a new method for the construction of p-y curves and for static loading conditions, p-y curves proposed by Dewaikar and Poonam (2005) are used. An iterative analysis is employed with secant modulus approach using a matrix method known as moment area method developed by Sawant et al. (1994). For pile top deflection of 20% of pile diameter, the load values are computed for both static and cyclic conditions. The comparison of results with the field test results reported by Matlock (1970) shows a good agreement. A parametric study is further carried out to examine the effect of load eccentricity, pile embedment length, diameter and the number of cycles on the pile response. The results of this study are discussed in the paper.

Jan 1, 2006

By Karen C. Armfield, Gisele R. Passalacqua, Joanna Smith

New York City is an urban environment with a history spanning over 200 years. The coastline of New York has changed over the years. In the East River, old bulkhead and remnant of relieving platforms together with variable bedrock elevations pose challenges in the design and construction of deep foundations. This paper presents a Case History of high capacity deep foundations along the Franklin D. Roosevelt (FDR) Drive on the Upper East Side in New York City. The project consists of a ramp that overpasses the FDR Drive allowing heavy trucks to access the Marine Transfer Station (MTS) facility built over the East River. Large diameter drilled shafts and mini-piles socketed to bedrock were designed and constructed. Remnant of old bulkhead was encountered at the site and a Ground Penetrating Radar (GPR) investigation was completed during the subsurface investigation phase of the design. This paper discusses details of the subsurface investigation program and design methodology of the high capacity drilled shafts and mini-piles. It also describes construction methods and results of Osterberg Load tests documenting the field values of skin friction through the rock socket. Other construction challenges include construction and drilling rock sockets for drilled shafts over sloping bedrock. 1. INTRODUCTION New York City is a renowned urban city that always calls for the most delicate, yet complex, and robust superstructures and most importantly substructure designs. The historic preservation of this large 200 years old city of 319 square miles is ever changing. Shorelines are often extended to accommodate new infrastructure and very often many miscellaneous structures are discovered below the ground surface. The East 91st Street Ramp was constructed to provide access to the East 91st Street Marine Transfer Station over FDR Drive and York Avenue. Another alternative ramp will be relocated to the South Bound (SD) of the FDR Drive at 92nd Street. A subsurface exploration program was completed in accordance with the New York City Department of Design and Construction (NYCDDC) general requirements, Section 4.5, to perform subsurface investigation along the FDR Drive in Manhattan, New York.

Jan 1, 2019

By S. W. Miller

During the examination of welds made in steel by the oxy-acetylene and electric-arc processes, the writer has met with some unusual structures, which he has not encountered elsewhere. They seem to be quite closely associated with the welding methods used, and characteristic of them, and would seem to be worth noting, especially as the references to them in the literature are few, and their explanation not clear or complete. An introductory word or two about fusion welding may not be out of place. The oxy-acetylene process is based on the great and very local heat generated by the burning of acetylene in the presence of commercially pure oxygen, the two gases being thoroughly mixed before combustion. The theoretical temperature is somewhat under 4000" C, but on account of various losses, the actual maximum temperature is probably about 3000" C.' The electric-arc process, using a metal electrode, which is also the filling rod, generates a still higher and more local temperature. The actual temperature of the positive crater of the carbon arc is given as 3500" C.2 NO figures have been found for the temperature of the arc using a metal electrode, but it would probably not be very different from that of the carbon arc, and probably higher than that of the bxy-acetylene flame. The greater localization of the electric arc is due to the fact that it is not surrounded by a large envelope flame, as well as to its higher temperature; while the oxy-acetylene white cone, or welding flame, in which the carbon of the acetylene is burned to CO, is surrounded and preceded by a long envelope flame, itself of quite high temperature, in which the CO is burned to GO2, and the hydrogen of the acetylene to H2O. This flame spreads around and over the pieces being welded, heating them to a further distance from the weld than does the electric arc.

Jan 1, 1918

By Jack L. Taylor

As expected from similar crystal structures and favorable atomic size factors, titanium, vanadium, and molybdenum are completely soluble in one another above the transformation temperature of titanium. The fl phase parameters of the continuous solid solution are shown graphically. Limiting compositions for retained fl phase have been determined. VANADIUM and molybdenum both have body-centered-cubic structures at all temperatures and, from the atomic diameter comparison factor, 3.9 pct, would be expected to form a complete series of solid solutions. The existence of complete solubility has been confirmed by work' at the Jet Propulsion Laboratory. Furthermore, vanadium and molybdenum have favorable atomic size factors to form complete binary solid solutions with the B phase, high temperature form of titanium, which also has body-centered-cubic structure. Pietro-kowsky and Duwez' and Hansen et al." have established the existence of the complete series of solutions in these binary systems. It would be logical, therefore, to expect that p-titanium, vanadium, and molybdenum would be completely soluble in one

Jan 1, 1957

By Edward Jr Walter

This paper discusses the problems that arise in the process of developing adequate explosives noise legislation. Case histories are used to illustrate how and where these problems arise and the course of action followed in overcoming them. It is imperative that those concerned keep informed as to possible legislation and be prepared to present solid facts that will insure fair and reasonable controls.

Jan 1, 1975

By D. K. Ingram, G. L. Mowrey, T. R. Rehak

Problem: Blasting is a hazardous component of surface mining. Serious injuries and fatalities result from improper judgement or practice during rock blasting. This paper describes several fatal injury case studies, analyzes causative factors, and emphasizes preventive measures. Method: This study examines publications by MSHA, USGS, and other authors. The primary source of information was MSHA’s injury-related publications. Results: During the 21-yearperiod from 1978 to 1998, the mean yearly explosive-related injuries (fatal and nonfatal) for surface coal mines was 8.86 (95% CI: 6.38 -11.33), and for surface metal/nonmetal mines 10.76(95% CI: 8.39 - 13.14). Flyrock and lack of blast area security accounted for 68.2% of these injuries. This paper reviews several case studies of fatal injuries. Case studies indicate that the causative factors for fatal injuries are primarily personal and task-related and to some extent environmental. A reduction in the annual injuries in surface coal mines was observed during the ten-year period of 1989 - 1998 [5.80 (95% CI: 2.71 - 8.89) compared to the previous ten-year period of 1979 - 1988 [10.90 (95% CI: 7.77 - 14.14)]. However, such reduction was not noticed in the metal/nonmetal sector, i.e., 9.30 (95% CI: 6.84 - 11.76) for the period 1989-1998compared with 11.00 (95% CI: 7.11 - 14.89) for the period 1979-1988. Discussion: A multifaceted injury prevention approach consisting of behavioral/educational, administrative/regulatory, and engineering interventions merits consideration. Impact on industry: The mining community, especially the blasters, will find useful information on causative factors and preventive measures to mitigate injuries due to flyrock and lack of blast area security in surface blasting. Discussion of case studies during safety meetings will help to mitigate fatal injuries and derive important payoffs in terms of lower risks and costs of injuries.

By P D. Munro

The spatial distribution of ore with similar processing properties or domains within an orebody may be identified early in the assessment of an orebody to provide a sound basis for later development of the orebody. The assignment of domains in the primary sulfide portion of an orebody is often more difficult than recognition of the oxidised, supergene and related domains usually located towards the top of the mineralised volume. This paper will discuss some approaches to assigning domains within the primary sulfide portion of an orebody. The processing properties of each mining block will be known if the contained domain(s) and their proportions are known. The use of both physical and chemical ore properties to assign the domains is discussed. The domains based on similar processing properties do not necessarily coincide with geological zones assigned by geoscientists. As part of assessing the physical properties of ore, the modal analysis of the ore with respect to the valuable sulfide minerals and the sulfide and non sulfide gangue minerals has to be known, along with the traditionally used elemental assays for valuable and penalty elements. Two scales for determining other physical ore properties will be considered: the mesoscopic scale (examined by human eye) and the microscopic scale (examined via a microscope under high magnification). The strengths and weaknesses of the data obtained at the two scales are discussed in the paper. Broadly, data collected at the mesoscopic scale are much less expensive but the types of data available are more limited. Methods for evaluation of chemical ore properties are also discussed. After establishing a basis for establishing the spatial distribution of domains, variability testing is required to verify the integrity of the designated domains. In contrast, each block of ore in some orebodies has been assessed principally via the results of a laboratory separation on a number of drill core samples or composites from throughout the block, with minimal or no attention to the concept of domains.

Jan 1, 2008

By A. G. Waters, N. J. Bristow

A comparative study was made of an untreated and a heated haematite ore and a sinter produced from a feed consisting of 100% ore, to study the influence on reduction behaviour of sinter bonding phases such as SFCA (silico-ferrite of calcium and alumina). Under low-temperature reduction conditions the order of increasing reducibility followed that of increasing porosity and surface area but under similar conditions at 900 degrees C the sinter exhibited higher reducibility than the ores even though the total porosity and chemical reducibility of the individual phases were lower. This behaviour can be explained in terms of the higher total porosity of the natural ore at low temperatures and the higher level of fine pores in the sinter at high temperatures due to the presence of SFCA, which acts to support the fine (c.0.1 micrometre) pores created by the reduction process. This leads to the conclusion that the main role of SFCA in sinter during high-temperature reduction is to maintain a high level of fine porosity. Some implications of this work for granule design and sintering practice are discussed

Apr 1, 1991

By Thomas A. Wright

No symposium on die-casting could be complete without consideration of the methods of formula and impurity control. No corisideration of control would be complete without discussion of that new tool of the analytical chemist and inspector, the quartz spectrograph. Just as there is an increased appreciation of the possible applications of the die-casting process and of die castings, so too is there, slowly but surely, of the spectrograph. At present the role of the instrument might well be compared with that of brass or magnesium die castings. Neither is as widely understood or known as they will be. Product specifications are increasing and are getting more explicit and often more rigid. The designer, metallurgist and production engineer or superintendent will be forced to depend more and more on the chemical laboratory. Sampling, as well as analyses, testing and inspection problems will grow. The chemical laboratory must meet its increased responsibility and use of the spectrograph will become more common. Advantages of increased precision, greater speed, lessened labor and often lower costs cannot be ignored. It will be the purpose of this paper in part to outline the respective fields of chemical and spectrographic analyses and to indicate where one may overlap the other and in part to indicate certain possible sources of contamination of zinc-base die-cast alloys in particular. Composition Aluminum.-Aluminum die die castings are expected to conform to the specifications of the Amcrican Society for Testing Materialslt and the Society of Automotive Engineers2. The A.S.T.M. has recognized seven aluminum alloys in Tentative Specification B85-33-T. TWO are straight silicon and the remainder are of the copper-silicon type of which alloys VIII and IX have in addition respectively 2 and 4 per cent of nickel, but unlike the others are not covered by S.A.E. as well. All seven call for rigid control of certain impurities. With the exception of alloy XII,

Jan 1, 1935

By Thomas A. Wright

No symposium on die-casting could be complete without consideration of the methods of formula and impurity control. No corisideration of control would be complete without discussion of that new tool of the analytical chemist and inspector, the quartz spectrograph. Just as there is an increased appreciation of the possible applications of the die-casting process and of die castings, so too is there, slowly but surely, of the spectrograph. At present the role of the instrument might well be compared with that of brass or magnesium die castings. Neither is as widely understood or known as they will be. Product specifications are increasing and are getting more explicit and often more rigid. The designer, metallurgist and production engineer or superintendent will be forced to depend more and more on the chemical laboratory. Sampling, as well as analyses, testing and inspection problems will grow. The chemical laboratory must meet its increased responsibility and use of the spectrograph will become more common. Advantages of increased precision, greater speed, lessened labor and often lower costs cannot be ignored. It will be the purpose of this paper in part to outline the respective fields of chemical and spectrographic analyses and to indicate where one may overlap the other and in part to indicate certain possible sources of contamination of zinc-base die-cast alloys in particular. Composition Aluminum.-Aluminum die die castings are expected to conform to the specifications of the Amcrican Society for Testing Materialslt and the Society of Automotive Engineers2. The A.S.T.M. has recognized seven aluminum alloys in Tentative Specification B85-33-T. TWO are straight silicon and the remainder are of the copper-silicon type of which alloys VIII and IX have in addition respectively 2 and 4 per cent of nickel, but unlike the others are not covered by S.A.E. as well. All seven call for rigid control of certain impurities. With the exception of alloy XII,

Jan 1, 1935