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By James T. Finley

Profit, product quality, speed of operations, reliability, operator confidence, safety and environmental improvements have all been enhanced as a result of the recently completed maintenance, renovation and construction program at Crown Central Petroleum Corporation?s (Crown?s) coke calcining unit at its Pasadena, Texas refinery. (Figure 1) BACKGROUND The calcining unit was built in 1969 - 1970 and has been operated continuously. Approximately 400 to 500 TPD of high quality metallurgical grade coke is manufactured, stored, and shipped to consumers. About 1/2 of the feed stock to the calciner is manufactured in Crown's coking unit and the remainder is received, via barges, from various sources. The green coke is off loaded from the barges with a conventional grab crane that discharges into a small travelling hopper over a conveyor belt that feeds a radial stacker, which forms a stockpile on the ground. The green coke, from the coking unit at the refinery, is moved to the calcining unit with front end loaders. Reclaiming from the stockpiles is also done with front end loaders. The coke is primarily handled by covered conveyor belts. The finished product is stored in steel silos and can be shipped via railroad cars, but the majority of it is shipped out in ocean going bulk carriers. Maintenance work in the calcining unit is performed by Crown's refinery maintenance department on an as needed, on call basis.

Jan 1, 1983

By Louis A. Panek

INTRODUCTION Block caving is distinguished from other types of mining in its requirements that the mineral body to be extracted must cave after a relatively large tabular open¬ing is created underneath it, and that the caving must be predictable and controllable for both operating and safety reasons. A mineral body that caves readily may present special problems with respect to ground support in the mining access openings, where stability, rather than failure, is the desired objective. The complete ex¬traction of a caving block, which may measure 50 to 100 m on a side and 100 to 300 m in height, tends to create a large void, resulting in significant changes in the ground stress system and a migration of rock from all directions toward the void; these events begin very early in the life of the mine and lead to additional spe¬cial problems with respect to control of ground move¬ments in the mine working areas, in the rock adjacent to the caving stope, and on the subsiding surface above the mine. Thus, the mechanics of an undercut-cave operation involve a broad range of geotechnical subject matter, including the determination of the lithostatic earth stresses, the structural properties of a large jointed rock mass, the flow properties of the fragments after caving, the stability of tunnel-like openings, and the stability and displacements of the rock structure (1 to 2 km in size) that surrounds the ore body. The objectives are achieved by in-place measurement of rock properties, laboratory tests, theoretical structural analyses of the related prob¬lems, measurements of structural behavior in and above the mine, and comparison of theoretical predictions with actual performance in order to interpret and refine the predictive capability. Undercut-cave mining (Julin, et al., 1973) differs from most other methods in that the caving is an essen¬tial and inherent part of the excavation process and in¬volves the movements of millions of cubic meters of rock over distances of hundreds of meters, as compared to the gradual 2-m settling of the overburden typical of full¬caving longwall coal mining. Undercut-cave mining may involve a rock mass on the scale of a 1-km diam open¬pit mine, but mining is several times deeper than that in the open-pit mine; furthermore, a large portion of the rock mass is in a failed, rather than a stable, state. Ground-control problems are inevitable in a situa¬tion where ground movements are occurring on such a large scale, and where the rock mass is expected con¬veniently to cave at one location but to be stable at an¬other. To devise effective responses to these ground¬control problems, one needs to know first of all what is happening, not merely at the point where the symptoms are observed, but more broadly with respect to the be¬havior of the entire mine rock-mass structure over the total area of extraction, including the effects on the sur¬face as well as those underground. Monitoring structural behavior on this scale would require a sizable group of people, if they attempted to measure all the significant mining-induced changes of ground displacement and pressure, even on a 100-m grid of points. The practical approach is to conduct the mea¬surements activity by a judicious sampling, making in¬termittent, concentrated efforts in selected areas of lim¬ited extent to study problems of immediate importance; simultaneously a minimum level of surveillance is main¬tained over the total structure to delineate long-term be¬havior trends in the major structure, which provide the baseline reference data that are so essential for interpre¬tive purposes. Mine-structure behavior depends not only on the mine extraction configuration and sequence, but on the rock structural properties and how they change from one location to another in the mine. Increasing attention is being given to determinations of rock strength and de¬formation by performing mechanical properties tests in place and in the laboratory, and by drawing inferences from the mapping of geologic structure in mine openings as they are driven and from the logging of cores ob¬tained from exploration drilling that may be performed primarily for delineating ore reserves. Monitoring of mine-structure behavior and inter¬preting it in terms of the growing excavations and the structural properties of the rocks have significant im¬pacts on designing the major undercut-cave operations of undercutting and drawing the ore, supporting the ac¬cess openings, and controlling surface subsidence. The purpose of this chapter is to call attention to the com¬mon ground-control problems encountered in undercut¬cave mining, to relate them to the mining process, and to explain the geomechanical approaches to analyzing these problems with emphasis on methods that are most readily available to the mine staff. UNDERCUTTING, CAVING, AND DRAWING A distinguishing characteristic of an undercut-caving method of extraction is the objective that the rock mass fails of its own weight in a predictable and controllable manner, after it is undercut by excavating a tabular¬shaped void, horizontal or inclined. Induced or forced caving refers to procedures that may be resorted to when the ore will not self-cave over the desired span. Block caving, panel caving, and mass caving are terms used to denote the particular sequence of undercutting and ex¬tracting the total area of the ore body on a single min¬ing level. The discussion herein is not specialized to any of these variations; the word block as used does not imply anything as to sequence. CREATING THE UNDERCUT A common undercutting method is to drive a series of drifts and blast the intervening pillars. Theoretical structural analysis and practical experience show that ground-support problems in the undercutting drifts and in underlying access openings as well (the same princi¬ple applies even if undercutting is done by belling out drawpoints from the slusher drifts) are minimized by retreat-mining across the undercut slot according to a sequence such that the growing undercut area retains a

Jan 1, 1982

By A. Tobey Yu

The smelter is the heart of a copper producing operation. Its principal function is to reduce and convert raw copper concentrates and/or leach plant precipitates into blister copper before it is refined. In addition to concentrates and precipitates, typical feed to a smelter also encompasses matte chips, flue dust, flux and lime. By nature, the characteristics of these materials are extremely variable, ranging from sub-micron to lumps, from slurry to dust, from abrasive to corrosive and free-flowing to adhesive. Furthermore, as a result of geological formation, most of the world's open pit copper mines are located in a semi-arid zone, where precipitation is minimal. This particular climate compounds the problem of handling these materials.

Jan 1, 1976

By Cheng Ang, Yun Bai, Zhi Liu

"This paper presents a conceptual design of an innovative tunnelling method named the Ring Pipe Jacking Method (RPJ) which is conducted by the Ring Pipe Jacking Machine (RPJM). The RPJM consists of a double ring shell which forms a ring section where small interlaced cutter heads or several micro tunnelling machines are assembled to cut soil. Similar to the conventional pipe jacking method, the RPJM also needs a thrust system, a slurry transport system, and a control system. To satisfy the need for large/super large or special section tunnels in future, the RPJM is designed to reduce sharply the excavation face to the annular section, thus enhancing the face stability. Part of the innovation is that the RPJM uses modular cutter heads or micro-TBMs which can be reused. The typical double shield shape can be easily changed by reinstalling the modular cutter heads. Modularity allows the tunnel to be cut in any cross-section shapes, ranging from a circular tunnel to a rectangular one. INTRODUCTION The demand and requirement to utilize urban underground space is rising with the rapid social development in recent years. It is necessary to reduce excavations of the urban ground surface to ensure smooth traffic in cities. Therefore the conventional open cut construction method for underground tunnels can no longer satisfy the need of practical engineering, and it is taken over by trenchless technologies .The Pipe jacking method is an important trenchless technology and is used more and more frequently to install underground pipelines, but the present pipe jacking method still has many problems. For example, it is not suitable for installing large-diameter tunnels and it also has difficulty in construction of short radius curved tunnels. This paper presents a conceptual design of an innovative pipe jacking machine named the Ring Pipe Jacking machine (RPJM) and introduces the correspondent Ring Pipe Jacking Method (RPJ) which can be applied to construct large-diameter tunnels. Furthermore, technical characteristics and superiority of the ring pipe jacking method are analyzed in this paper."

Jan 1, 2016

By Karen L. Menna

At Digital Equipment Corporation, increasing demands on executive secretaries to share, track, and retrieve information prompted development of ALL-IN-1 System for Executive Services. Executive secretaries asked engineers to combine word processing and electronic mail with utilities for managing time; logging and tracking telephone calls, letters, and inquires; creating presentations; compiling directories; and archiving. The system, two years in development, now automates the president's and senior vice presidents? offices at Digital. It allows secretaries to interrupt any task with two keystrokes, and return later to the original task. The system has speeded customer response, enabled online information sharing, and increased professionalism and customer satisfaction.

Jan 1, 1989

By A. J. S. Spearing, A. Mueller

The support of intersections in coal mines remains an important safety issue, mainly because the large diagonal span compromises the stability of the roof. This structural weakness is further exacerbated if the intersection is developed incorrectly, the pillar corners fail or the crosscuts are angled (not perpendicular). This report details the current support systems used and investigates unplanned falls of ground in intersections in coal mines throughout the United States. A possible failure mechanism is proposed and some suggestions are made to improve the effectiveness of the support in these vital areas.

Jan 1, 2009

By R. D. Auten

This paper is primarily a report on the process of using oolitic aragonite, as received from Marconi& Ocean Industries, Ltd. without further processing, for a major portion of the raw feed to a rotary kiln producing cement clinker. Oolitic aragonite is a high purity calcium carbonate material, dust free, with the appearance of a course, white sand. It is farmed when under the right conditions of temperature ocean currents, and ocean floor topography. The calcium carbonate will precipitate into small spherical particles on the ocean floor. These oceanic conditions are correct to cause precipitation of the calcium carbonate near Ocean Cay in the Bahama Island chain. The present growing deposit near Ocean Cay is in the billions of tons and is mined by a relatively shallow-operation hydraulic dredge. The aragonite thus formed is en orthorhombic crystaline form of calcium carbonate with a specific gravity of approximately 2.9. At a temperature of 505°C. (940F), the aragonite converts to the hexagonal crystal of calcite with a specific gravity of 2.6 to 2.7. This change in specific gravity weakens the structure of the particles but the individual pieces are still fairly hard. When the material is then calcined at 900°C (1650°F), the particles retain their shape but become soft and will break up under finger pressure.

Jan 1, 1978

By Charles Kocsis, Pedro Nascimento, W. Patrick Arnott, Samuel J. Taylor

Respirable crystalline silica (RCS) is an inhalation health hazard for mining and industrial work environments and must be monitored. We provide theoretical analysis of real-time measurements for determining RCS mass concentration without the use of filters by using photoacoustic spectroscopy. The suspended dust in the mine air can be continuously sampled by the photoacoustic instrument. A tunable quantum cascade laser is the light source, allowing for determination of interferences such as kaolinite, coal dust, and water vapor. The most useful spectral region is found to be between 11 and 13 μm. Absorption by water vapor, and, to a lesser extent, carbon dioxide, in this spectral region has gaps that allow for quantification of the aforementioned dust species as well as a convenient check on the calibration of the instrument. This work brings photoacoustic measurement of aerosol to the mid infrared range where spectrally dependent light absorption can be used to quantify dust composition and mass concentration.

Jul 31, 2022

By William Gleason

"Mining roots run deep in Glenrock, WY, a town that was founded in part, because of the coal mining that began in the late 1800s. But that rich history also now threatens large parts of the town that were built over the top of the mines. Like many towns in the Western United States, mining is a proud part of the historical fabric and heritage of the town, but the legacy issues from past mining activities continue to present challenges to modern-day engineers.In the case of Glenrock, a small town about 40 km (25 miles) east of Casper, it is flooding from a century of water that has accumulated in the down geologic dip of the furthest northeastern extent of 87 ha (217 acres) of mine workings that has made the town susceptible to sinkholes and other issues (Fig. 1).Full commercial coal mining production began in Glenrock in 1887 during the development of the Fremont, Elkhorn and Missouri Valley railway. Due to poor overlying roof rock and continuous flooding within Glenrock, Mines No. 1 and 2 were fully closed in 1909. During its history, an estimated 87 ha (217 acres) were mined with 50 to 60 percent extraction ratio within the eastern town limits through room-and-pillar mining. It is estimated that the mines produced 22 kt/a (25,000 stpy) during their lifetime. A century later, the water pressure built up in the northeastern most portion of the mine has created serious concerns for residents.In 2016, the Wyoming Department of Environmental Quality’s Abandoned Mine Lands Divisions (AML) investigated a number of subsidence events in the town including sinkholes following heavy precipitation. The AML investigations confirmed that most events were related to the previous mining in the area.Mitigation efforts on the mines were done in the 1980s and 1990s, but the problems in the town and in a nearby subdivision persisted, leading the AML to search for alternative solutions."

Nov 1, 2019

By Henning Schwarz, Faisal Al Arifi, Anas Almousa

"The Riyadh Metro Project forms part of a complete new public transport system integrated in the urban planning and development of the fast growing capital city of the Kingdom of Saudi Arabia. The Design & Build project consists of 176 km of a new metro network with 57 km of double track single tunnel infrastructures, spread over six metro lines. During the design phase, geological, hydrogeological, geotechnical and geophysical site investigations were undertaken to chart the, previously uncharted, underground construction space. Different TBM solutions were selected for implementation taking due consideration of the ground conditions of each metro line. The results obtained from deep excavations for underground stations and analysis of the TBM tunneling data will be used as key input for future tunneling projects in the Riyadh and the Kingdom of Saudi Arabia. The present paper details the design conditions and presents the solutions for large diameter tunnels in karstic limestone. INTRODUCTION The High Commission for the Development of Arriyadh was established in 1974 as the organizational, planning, executive and coordinating body responsible for the development of Riyadh. Arriyadh Development Authority (ADA), established in 1983, is the High Commission’s executive, technical and administrative arm. The ADA is responsible for implementing the High Commission's organizational, planning, executive and coordinating decisions and missions (ADA 2015). One of the remits of the ADA is the preparation and execution of a transport plan for the city. The metro network is planned to be the backbone of the public transport system developed as part of the King Abdulaziz Project for Riyadh Public Transport in Riyadh. With six lines and a total length of 176.5 km (Table 1) and 85 metro stations, the metro network will cover most of the densely populated areas, public facilities, and the educational, commercial and medical institutions. The network will connect the King Khalid International Airport, the King Abdullah Financial District, main universities, Riyadh downtown and the public transport center. The public transport plan includes a future bus network with 22 lines on 1200 km and 6765 stops that will be the main feeder for the Riyadh metro network; it will also be the main mode of transportation within and around Riyadh districts (ADA 2015)."

Jan 1, 2016

By J. F. Hunt

[THE AUTHOR DESCRIBES THE ACTUAL PROCESSING OF THE GOVERNMENT STOCK¬PILE OF CHROMIFEROUS SANDS. LOCATED AT COQUILLE. OREGON, DURING 1955 AND 1956. A GENERAL HISTORY OF THE STOCKPILE IS GIVEN, ALONG WITH A BACKGROUND OF THE GEOLOGY AND ORIGIN OF THESE SANDS. THE FLOW SHEET USED IN THIS OPERAT ION IS OUTLINED IN DETAIL, AND THE MINERALS WON FROM THE STOCKPILE BY HIGH TENSION AND MAGNETIC PROCESSING ARE DISCUSSED AS TO THEIR PURITY AND SALEABILITY. AMONG THESE MINERALS ARE CHROMITE, ILMENITE, MAGNETITE, ZIRCON, GARNET, RUTILE, MONAZITE, GOLD, AND PLATINUM. PLANNED POST-STOCKPILE OPERATIONS ON THE PRESENT BEACH DEPOSITS ARE DISCUSSED. THESE OPERATIONS WOULD HAVE BEEN CARRIEDOUT TO SET UP A' CONTINUOUS INTEGRATED MINING AND BENEFICIATION PROJECT, EXCEPT FOR UNFORESEEN CIRCUMSTANCES WHICH DICTATED THE CLOSING OF THE OPERTIONS AT THE EXHAUSTION OF THE GOVERNMENT STOCKPILE. THE PAPER IS ILLUSTRATED WITH MAPS, FLOW SHEETS, CHARTS; AND PHOTOGRAPHS OF STOCKPILE, PLANT, AND EQUIPMENT.]

Jan 1, 1964

By Paul B. Valenti

The Nevada Moly Operation of Anaconda Minerals Co., (a molybdenum/copper ore body) was initiated in 1978, with a contract to Bechtel Civil and Minerals Inc. for construction of a mining and milling facility near Tonopah, NV. Ground was broken on the concentrator portion of the project in August 1979$ with a multi-phased startup of the mill beginning in June 1981. Processing design tonnage of 20 000 t/d (22,000 STPD) was reached in early 1982. Major pitfalls of rapid design and implementation of engineering, construction, and startup are considered. The operation of the concentrator including SAG milling, ball milling, bulk rougher flotation, copper/moly separation, moly regrinding and cleaning, thickening, and product loadout are discussed.

Jan 1, 1983

By M. G. Schulz

Mining of molybdenum at Questa, New Mexico has been accomplished by block cave methods since August, 1983. As caving progresses, a periodic geologic evaluation is made of the rock-types present in finger raises on the Grizzly Level of the mine. The production maturity of the cave can be monitored by relating this data to geologic cross-sections through the ore body. The draw point mapping program is a simple and effective tool that is used in making draw control decisions at Questa.

Jan 1, 1985

By ANA E. BOHE, MICCO GEORGINA DE, GASTON G. FOUGA, JUAN P. GAVIRIA, FEDERICO J. POMIRO

To the best of our knowledge, this paper comprehensively summarizes a thorough study to determine the thermodynamic viability of the reactions between light rare earth oxides and chlorine with and without carbon. The kinetics and mechanisms of light rare earth oxide chlorination and carbochlorination reactions are analyzed and discussed according to results in the literature. Lanthanides between lanthanum (La) and gadolinium (Gd) are considered as light rare earth elements (LREEs) in agreement with previous literature and the results detailed in this review. Both laboratory- and industrial-scale light rare earth chlorinations and carbochlorinations, starting from oxides and ores, are reviewed.

By M. Woodie

INTRODUCTION Information such as application review to choose the proper style of vibrating screen, parameters that determine the proper size of vibrating screen, engineering design information that governors proper screen design, review of topics that govern proper isolation from structural steel and other topics that dictate proper screen selection for applications will be presented in this paper. Topics like process and application information review to choose the style of screen and how material size and type influences proper type of screen selection (multi-slope, incline, horizontal, linear incline or dewatering) will also be discussed. Parameters will be reviewed that help size the screen for the application. The total amount of surface area to size a screen is critical to the overall success of a screen installation. Once proper style of screen is determined there is an engineering process that is required to design the screen to operate correctly in the environment it will be used. Finite Element Analysis, Dynamic Modeling, Field Vibration Analysis and other engineering tools will be reviewed to best implement a successful vibrating screen installation. TYPES OF SCREENS Multi-Slope Multi-Slope vibrating screens are used where sizing large amounts of tonnage on surface areas that would be smaller than conventional screening where roughly 6” (150mm) minus material is required to be sized. Occasionally larger particle sizes can be screened on the Multi-Slope machine but the effectiveness of the machine can be diminished with larger particle sizes and larger than 4” (100mm) screen opening. The most common and effective size range of screening with these machines is 2” (50mm) minus material. The Multi-Slope screen is used where particle size is not extremely important. Mineral processing, hard rock mining and industries where exact material size is not critical are best suited for this equipment. Because the aggregates industry requires very specific material sizes, the Multi-Slope screen is not suited for most aggregate screen applications. The key to the success of a Multi-Slope screen is proper material presentation at the feed end of the screen. This allows for the material to stratify quickly and disperse the fines through the screen quickly with a relatively thin bed depth at the feed end which allows the undersize material through the screen quickly.

Jan 1, 2019

By Steven M. Bishoff

The reclamation of surface land areas disturbed during the course of coal recovery became a major, universal consideration upon the implementation of the Surface Mining Control and Reclamation Act of 1977. This legislation not only established reclamation as an absolute requirement, but also presented guidelines for reclamation standards and required bond-posting procedures to assure completion of the reclamation process. The Office of Surface Mining was established to enforce the provisions of the Congressional mandate by promulgating specifically detailed regulations and supervising the State participation in this regulatory process. The major operational consequences of the reclamation-related provisions of the Act and the OSM regulations are the increased costs and complex procedures necessary to accommodate the regulatory authorities. It is anticipated that many of these costs and procedures have not been adequately evaluated by either the coal operators or the regulatory bodies. It is, therefore, necessary to proceed with an examination of the general reclamation processes, the effect of these processes on product costs, and the methods, if any, which may be utilized to minimize their impact on the overall operation.

Jan 1, 1981

By James Withers, Dongbo An, Jinhong Zhang

A micro-scale investigation was carried out by applying atomic force microscopy (AFM) to study in situ the adsorption of various collectors, i.e., oleic acid, octanohydroxamic acid (HA), and salicylhydroxamic acid (SHA), on bastnaesite in aqueous solutions. The obtained AFM images show that the surface morphology of bastnaesite changes greatly after it comes into contact with the solutions of the collectors, suggesting that all these collectors can effectively adsorb onto bastnaesite. Increasing temperature can facilitate the adsorption of oleic acid onto bastnaesite. Results from attenuated total reflectance–Fourier transform infrared spectrometry (ATR-FTIR) also show that all of these collectors adsorb strongly onto bastnaesite, with strong absorbance spectra being detected. The ATR-FTIR results confirm those obtained by AFM. In general, hydroxamic acid collectors (HA and SHA) adsorb onto bastnaesite mainly in the form of insoluble metal hydroxamate. This specific adsorption mechanism explains that a high selectivity with a moderate collectivity will be achieved with a hydroxamic acid collector for the flotation of bastnaesite.

By Alexander Filimonov, Yury Bloshteyn

Ventilation of gas mines keeps necessary sanitation and hygienic conditions for labor in mines and increases the safety by dilution and removal of hazardous and dangerous gases in accordance with the safety rules. Several different concepts exist at the present time to design mine ventilation control systems. But technical ideas have been developed inadequately and technological solutions have not been investigated experimentally enough to build a serviceable system. This paper presents a new concept of high- efficiency mine ventilation process control system (MVPCS). The methods of modern system engineering (Kalman, 1969) are used to establish its functional and algorithmic structure. A three level hierarchical principle of system building is considered.

Jan 1, 1991

By Chien-Tsun “C. T. ” Chu, Drupad B. Desai, Ron E. Redd

The 12,710-m (41,720-ft) Riverside Badlands Tunnel is located between the most active faults—San Andreas and San Jacinto—in Southern California. To accomplish the impervious final lining design and to accommodate the effects of earthquake ground motions, a new approach was developed and is prescribed in this paper. Two final lining options, welded steel pipe and prestressed concrete cylinder pipe, are considered for the tunnel, which will be excavated under groundwater and ground conditions from soft rock to hardrock at depths exceeding 244 m (800 ft). The buckling strength, serviceability, and structural integrity under seismic effects and other loads were considered in the design.

Jan 1, 1997

By Enrique Levy

The publication from which this paper was abstracted is the first at-tempt to correlate all the metallogenic deta compiled by the author for the preparation of the 1:2,000,000 Metallogenic Map of Central America. It is not a treaty of metallogenic theories but rather a careful effort to postulate metallogenic provinces and epochs with the intention to stimulate other geologists and mining companies familiar with the area to criticize and improve on the ideas proposed. The sole purpose being to find new mineral deposits for the betterment of our people.

Jan 1, 1971