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By G. Kris Kapoor

Each new period of public concern, whether rooted in things political, social, economical, or technological, brings with it new words or phrases which highlight that new interest. With people's awareness of our rapid depletion of readily available energy sources and the enormous increase in energy .costs came the new, and now often heard, terms "energy intensive", "energy sensitive", and "energy conservation". Since its birth in 1926, Fuller Company had been directly associated and involved with energy intensive products and processes. We are located in the heart of the Cement Industry. Many of our products and processes are geared to the needs of the portland cement manufacturer, and a look at the inferno within an operating cement or lime kiln will certainly convince anyone that here is an energy intensive process. Fuller Company, then, has always been energy sensitive. Process kilns, hard rock crushers, tube and roller mills, fluid bed thermal reactors, pneumatic compressors and conveyors, material coolers - all are Fuller Company products utilizing or transferring large amounts of energy. Consequently, much of our success in the marketplace depends on how wisely we design and plan for efficient use of power and for conservation of each unit of heat available.

Jan 1, 1975

By R. L. Godfrey

The Custom Coals advanced coal cleaning plant will be designed with a unique blending of existing and new processes to produce two types of compliance coals: Carefree Coal? and Self-Scrubbing Coal?. Carefree Coal will be produced by cleaning the coal in a proprietary dense media cyclone circuit utilizing fine magnetite to remove up to 90 percent of the pyritic sulfur and correspondingly greatly reduce the ash. While may utilities can achieve full S02 reduction compliance with Carefree Coal, others face higher sulfur reduction requirements due to the higher sulfur content of their existing fuel supplies. For these circumstances, a patented Self-Scrubbing Coal will be produced by taking Carefree Coal and pelletizing limestone-based additives with the finest fraction of the clean coal. These technologies will enable over 150 billion tons of non-compliance U.S. coal reserves to meet compliance requirements.

Jan 1, 1995

By X. Cai, L. Jiang, G. Fu

A process for recovering manganese from low-grade manganese oxide ore through a reduction acidolysis-selective leaching method is investigated. Two types of biomass, sawdust and straw, were used as reductants. Reduction acidolysis, using concentrated sulfuric acid, was used to disrupt the structure of the biomass, allowing the biomass to be hydrolyzed into monosaccharides. Analysis by X-ray diffraction revealed that Mn2O3 was reduced to MnSO4. Then, in the selective leaching process, iron was removed through the formation of goethite. The optimized experimental parameters are as follows: reductant to ore mass ratio of 0.4, sulfuric acid to ore mass ratio of 0.9, water to ore ratio of 0.5, aging time of 18 h, leaching temperature of 95 °C, leaching time of 90 min, and solution pH of 2.5 to 2.8. Under these conditions and using sawdust as the reductant, the manganese leaching efficiency and iron removal efficiency were 91.8 and 99.2 percent, respectively.

By M. Spangler

FirstMiss Gold installed a supervisory control system based on Pavilion Technology's Process Insights neural network software and Oil System's PI data historian. The primary goal of the system was to control the acid preconditioning circuit. However, our first successful control loop was on the limestone feed rate to the neutralization circuit. The information gained by modeling these circuits and the better control provided by the system has resulted in reagent savings of over $80,000 per month.

Jan 1, 1995

By S. M. Pickering, L. T. Gregg

Appraisal of industrial minerals beneath privately owned land requires a different approach and mindset from valuation of base and precious metals or energy minerals, and from valuation of government-owned mineral lands. First, is it the value of inground minerals or of mining rights that is being sought? Second, value to whom, the mining company, a potential investor, the mineral landowner, a lending institution, the property tax assessor, or a condemnor? Third, how should mineral value be apportioned between the land and mineral owner, and a mining company with limited years of lease-hold interest? These and many other questions must be addressed before a valuation method and Discount Rate are selected. For various reasons the Income Method is most often used, with Net Present Value calculations made for long term predicted mining income. Choice of an appropriate Discount Rate is critical.

Jan 1, 2000

By Y. Wang

Wet magnetic separation methods for recovering hematite and chromite fines and ultrafines are investigated in this paper. These methods include wet high intensity and high gradient magnetic separations, carrier or "piggy-back" magnetic method, magnetic field-induced aggregation and magnetic seeding. This investigation indicates that wet magnetic separation is more efficient for fines and ultrafines whereas other methods can be used to enhance the particle aggregation and/or the magnetic response. The magnetic behaviour of these minerals with respect to magnetizing field, particle size and temperature is also presented.

Jan 1, 1993

By Isabel F. Barton, MarkD. Barton, Christian A. Rathkopf

Molybdenite is the world’s principal source of rhenium (Re), a critical element in multiple high-tech applications. However, the Re contents in molybdenite vary by orders of magnitude on scales ranging from single grains to whole deposits. In order to better understand the systematics of this variation and what geochemical factors control molybdenite Re concentration, and hence overall Re resources, we examine global patterns in molybdenite Re contents through a compilation of > 3000 measurements of Re in molybdenite from > 700 mainly ore-bearing moderate- to high-temperature hydrothermal systems of different types. Our results are similar to but expand on those of earlier studies. Rhenium concentration in molybdenite has a lognormal distribution and varies systematically with type of geologic system, intrusive lithology, and Mo grade. The lowest-Re molybdenite occurs in greisens (geometric mean 1 ppm ± a multiplicative standard deviation of 9), quartz vein-hosted W-Sn deposits (2 ± 5 ppm), unmineralized granites and granodiorites (12 ± 8 ppm), intrusion-related deposits (24 ± 8 ppm), and porphyry W-Sn deposits (16 ± 11 ppm). Rhenium is most enriched in molybdenites from volcanic sublimates (23,800 ± 5 ppm), with skarn Fe and Au (560 ± 5 ppm and 540 ± 3 ppm respectively) and porphyry Cu and Cu-Au deposits next (470 ± 4 and 430 ± 7 ppm respectively). Among porphyries, skarns, and quartz vein-hosted deposits, Re is most highly concentrated in molybdenites from Cu and Au systems and its concentration decreases systematically through Cu-Mo, Mo, Sn, and W deposits. In nearly all cases, molybdenites from systems associated with intermediate igneous rocks contain more Re than molybdenites from systems of the same type with more felsic rock associations. The disparity between Re contents of molybdenite in felsic and intermediate systems is largest for porphyries, quartz vein-hosted, and skarn deposits and is near zero for subeconomic or barren granite and granodiorite Mo systems; felsic intrusion-related deposits have slightly higher molybdenite Re than their equivalents associated with intermediate intrusions. In most systems, molybdenite Re content does not correlate with metal grade, but may have an inverse correlation with Au grade in intrusion-related deposits (based on a small number of data points) and does exhibit a strong inverse correlation with deposit Mo grade. Dilution of Re through larger amounts (higher deposit grades) of molybdenite explains about 40% of this correlation, but the relative enrichment of Re in molybdenite from low-Mo deposits must also reflect some selective enrichment of Re/Mo in porphyry Cu systems compared to porphyry Mo systems. We found no evidence for secular increase or other systematic temporal variation in molybdenite Re content. The data regarding the use of molybdenite Re content as a proxy for mantle influence are ambiguous. Nearly all observed empirical correlations can be traced back to differences in redox state and sulfide concentration, the two geochemical factors identified here and by previous experimental work as the controlling influences on Re mobility under hydrothermal conditions. Hydrothermal systems with reducing conditions (W- and Sn-rich) tend to have low molybdenite Re even though compiled whole-rock data indicate that their source rocks have as much or more Re as those of more oxidized systems (e.g., Cu-rich). Vapor-phase exsolution, crustal assimilation, and mixing with external fluids may all enrich molybdenite Re concentrations in individual deposits and deposit types, but their extent and importance in overall hydrothermal concentration of Re is uncertain. Thus, it appears that the available molybdenite Re resource in an ore deposit largely depends on how the deposit’s redox and sulfidation conditions have varied over time and space during the timespan of hydrothermal activity. Oxidized, high-sulfide conditions tend to concentrate Re in molybdenite, whereas reducing conditions tend to leave Re dispersed at low concentrations in the bulk rock.

By Vas P. Srinivasa

A comminution circuit is an important integral part of a mineral processing plant. Nearly 40% of the capital cost and 30 to 40% of the operating cost are taken up by the crushing and grinding circuit. Therefore, considerable care should be given to the design and selection of this circuit. Several factors affect the selection of a comminution circuit--energy consumption, avail- ability of the equipment, the remoteness of location, and availability of trained personnel, to mention a few. Each of these factors influences the choice. Selecting a comminution circuit strictly on lower capital cost may not be optimal. Crushing and grinding circuits are usually site specific and should be selected - only after careful analysis of all the factors involved. The objective of this paper is to show the effect of these factors, which are extranious to capital cost. Usually, the capital cost of a semiautogenous grinding circuit is lower than that of an equivalent conventional circuit. However, due to lower equipment availability and high power costs in certain locations, the economic advantage of lower capital cost is lost. Analysis indicates that a break even point occurs at a power cost of 5¢/kWh. This paper describes the procedure utilized for selecting the most economic comminution circuit and states the conditions applicable for each cominution circuit.

Jan 1, 1983

By C. E. Golson

Modern concrete technology emphasizes the basic qualities required of an acceptable aggregate: it must be clean, sound, homogeneous, and of a size gradation resulting in a concrete of the desired physical qualities at a minimum cost. In the case of coarse aggregates, crushing, scrubbing, and screening will usually provide the required material, although beneficiation is often necessary in order to eliminate unsound or deleterious fractions. Beneficiation is also applicable to fine aggregates,( but the processes most often employed are washing, classification, and dewatering.

Jan 1, 1959

By J. C. Watts

Monitoring and control of conventional industrial wet grinding circuits is conceptually straightforward. However, since production objectives and operating constraints can vary widely from plant to plant, there is probably no single overall grinding circuit control strategy which is "best" in all cases; in-variably some compromise is necessary between performance desired under ideal conditions and performance achievable in practice. The recent advent of relatively low cost, reliable, high speed small computer systems is revolutionizing daily operations in increasing numbers of metallurgical processing plants. Of special power and capability is a hierarchical computer network like that currently in use at the Pinto Valley Operations of the Cities Service Company. Several satellite processors for key plant areas communicate with a master computer operating under a powerful multitasking real-time operating system. Hardware and software structure is such that downtime on one of the processors -including the master -does not have a major impact on overall system operation. Admittedly, the powerful, core efficient table driven satellite software, which handles process/computer communication, calculation of nonmeasured process variables, and basic Direct Digital Control functions, is difficult to modify. However, important high level process monitoring, report preparation, graphic display, and supervisory control functions -including economic optimization -can be implemented by project engineers at the plant site. Thus, for example, new control strategies can be quickly examined and rapidly evaluated. Such computer monitoring capability also permits use of short duration process pulse tests for approximate dynamic modeling and rapid calculation of controller tuning constants for single loop dominant systems. Following a brief back-ground discussion of the Pinto Valley Project, we present some of the more interesting results and conclusions of our work over the past year.

Jan 1, 1978

By John F. MacDonald

This paper describes the driving of a 400 m long by 25 m diameter highway tunnel through sensitive, overconsolidated silts and clays. The design concept requires the construction of the permanent support system, consisting of 24 concrete filled perimeter drifts, before excavating the mass core. General construction procedures used during the construction of the perimeter drifts are described.

Jan 1, 1985

By Ashraf A. M. A. Wali

Many of the economic resources of Egypt have been recognized and exploited for thousands of years (e.g. gold and copper). Most of these minerals, particularly those from hard-rock sited deposits, are found in complex form along with other components while those present in sedimentary sequences are largely in simple compounds or as native elements. Recognition of their characteristic settings (structure, basin development, environment of formation etc.) is the main clue in predicting and locating their presence. The main economic minerals exploited in Egypt today come from sedimentary sequences and include sodium and potassium chlorides, gypsum, sulfur, and sedimentary iron ores. Large amounts of low grade sedimentary phosphates are known but are not of economic value at today's prices. Recent intensive investigation in the north-eastern Sinai (EI Arish) and along the southern coasts of the Gulf of Suez has revealed new and extensive sulfur and chloride deposits, and considerable oil and gas are now being exploited from closely related sediments. Tin is the only mineral that is produced from hard-rock sources, and gold and copper deposits are present but not of high enough grade to be economically viable. However, a significant part of Egypt has not yet been studied in enough detail to close the door on future discoveries. Another point of considerable geological interest is the presence of diverse, modern evaporitic settings, from which we may draw the analogs for many of the older gypsum, anhydrite, chloride and sulfur de-posits. In fact these analogs are so well displayed that both the Sinai and Gulf of Suez-Red Sea evaporites (Middle and Upper Miocene) can be readily compared with these modern deposits.

Jan 1, 1990

By d&apos, I. J. Agati

The stockpiling and reclaiming of bulk materials can be a challenging task for engineers seeking the optimum solution for plant needs, reliability, and at lowest unit cost. The objective of this paper will be to expose advantages, disadvantages and limitations of many storage and reclaiming systems to the responsible engineer and management. The paper will emphasize the practical aspect of stockpiling and reclaiming methods. Many valuable and interesting papers are available dealing with the theoretical viewpoint and application of a particular manufacturer's machine. Several of these are mentioned in the bibliography. As many practical parameters as possible will be given. After twenty years in the field of designing and selling bulk materials handling systems, the needs of the user and the plant are recognized and reasonably understood. This paper cannot give solutions to all problems In this vast field but will stress practical applications and examples of various installations. The evolution of advancements in materials handling is based upon not only technological innovations, but learning from many experiences of others and utilizing them as stepping stones to improved installations.

Jan 1, 1969

By R. J. Hickson

The giant El Abra copper mine project under development in Northern Chile will come on stream in early 1997 at a production rate of 500 million pounds of cathode copper annually. Ownership is 51 % Cyprus Amax and 49% Codelco. Cyprus Amax has construction responsibility. Total project cost is $1050 million. El Abra will incorporate latest operational technology with labor efficient practices to achieve world class productivity levels and low initial cash costs of about US $0.35/lb copper. Development procedures for the almost 800 million ton oxide deposit, as well as the hydrometallurgical processes selected for recovery of the copper values are discussed. Construction costs and pertinent technical data are shown.

Jan 1, 1996

By Qinghua Gu, BUQING XUE, XUEXIAN LI, JIANGSHAN SONG, Qian Wang

To solve the problem of time-consuming and low precision in updating the open-pit vehicle transportation network, a high precision road network model construction method for unmanned vehicles in open-pit mines is proposed. This method can be divided into two steps. In the first step, an improved deep learning image processing model named DeepLabv3 + C (DeepLabv3 + Concat) is presented. Then, the road information extracted by the DeepLabv3 + C network is used to construct a three-dimensional model of the open-pit mine road network. In the second step, aiming at the time-consuming problem of unmanned vehicle meeting in open-pit mines, a vehicle meeting strategy was proposed. This strategy is used to guide the navigation of unmanned vehicles in open-pit mines. Besides, the DeepLabv3 + C network is verified by comparing the mIOU (means Intersection Over Union), accuracy, and continuity of road image extraction with the mainstream networks. The road network model constructed in the first step is quantitatively analyzed, and its performance is compared with GPS trajectory clustering methods. At the end of the paper, vehicle running simulation is carried out on the road network model by using Unity (a 3D visualization simulation software). The results show that the road network model constructed by this method can meet the navigation requirements of unmanned vehicles in open-pit mines, and the feasibility of the vehicle meeting strategy is proved.

Jan 11, 2022

By Sandy Worden

Coal mining companies in Australia are managing the high-consequence risks across their operations more effectively by using an interactive online risk management system known as Riskgate Developed by the Minerals Industry Safety and Health Centre (MISHC) at the University of Queensland, Australia, Riskgate contains detailed information about 11 high-consequence risk areas (called topics in the system) for opencut and underground coal mines (Table 1). The existing topics are: fires; strata control for underground mining; ground control for opencut mining; tires; isolation; collisions; explosions and explosives; manual tasks; and trips, slips and falls. Every Riskgate topic is focused on coal industry activities (mining, processing, transport and storage). The scope includes mine sites, lease areas and mine infrastructure (mobile, fixed plant, field equipment, buildings, road and rail transport), and all aspects of the mine life cycle from design through to decommissioning. The topics uniformly recognize that a loss of control can result in injury or fatality, equipment damage, production loss, reputation loss and environmental damage. However, the priority focus for Riskgate is the safety of mine personnel.

Jul 1, 2013

By Jeremy Stone, Yiming Sun, John Stolz

The Courthouse Commons Tunnel facilitates the secure transfer of inmates between the County Jail and State Courthouse across a city block in downtown San Diego, California. This shallow tunnel was excavated using the Sequential Excavation Method in soft ground. It passes under 8- and 10-story buildings with a foundation cover of 6 feet, and crosses the active San Diego Fault with a design offset displacement of 18 inches. In this paper, key design challenges of tunnel construction are presented: limiting building settlements without using underpinning of building foundations and incorporating an oversized seismic section with seismic joints and crushable backfill

Dec 1, 2022

By Clifford B. Farris

Introduction Shale Mining Problems The mining problems an oil shale operator will face are largely determined by the process. Candidate oil recovery processes are surface (above ground processing of mined oil shale), modified in situ (underground with some shale removed), and true in situ (completely underground with no shale removed). The shale removed for modified in situ (MIS) is generally processed by surface techniques. The mining problems are different for each category. Fig. 1 depicts the diversity of western shale deposits. Mining for surface operations will employ underground mining techniques in common use but the scale will be larger. A typical oil shale operation is expected to require 75,000 to 250,000 st (68 000 to 226 800 tons) a stream day of crushed oil shale. This is above the upper limit of current mining operations. Major problems include: (1) lack of good engineering design properties for oil shale, especially when interbedded with saline minerals at depths below 1,000 ft (305 m); (2) presence of water, hydrogen sulfide, and methane in some areas; (3) necessity for mine disposal of as much retorted oil shale waste as possible; and (4) control of environmental impacts of mining. Portions of the oil shale deposits in Colorado, Wyoming, and Utah and significant portions of the Devonian shales in the eastern U.S. are adapted to surface mining. No major technological problems are apparent outside overburden thicknesses up to 1,000 ft in the West. However, numerous political and environmental difficulties have arisen. One major oil shale developer cancelled a planned surface mining operation and currently is pursuing a modified in-situ plan. The eastern shales are closer to the surface than the western, but suffer from many of the same environmental and political problems. Modified in-situ operations face much more severe mining problems than surface efforts. Because the mined stope (called an in-situ "retort" by processors) acts as a retorting process vessel subject to gas flow, combustion, and temperatures between 1,500° and 2,000°F, mining is under highly restrictive limitations. This processing method involves removing between 20 and 40% of the shale deposit and then blasting the roof and walls into the mined space, where the oil is recovered by retorting. Major problems are: (1) swell factor severely limited; (2) need for consistent size distribution of blasted shale; (3) even filling of stope (in-situ retort) by blasted shale with consistent permeability throughout; (4) scaleup of blasting techniques, after optimization; (5) protection of retort pillars and roof during and after retorting; (6) prevention of groundwater percolation; (7)use of ANFO explosive in wet holes; (8) disposing of surface-retorted shale waste in stope; and (9) restoration of site. True in-situ operations are less well developed than surface or MIS processes. No actual mining is done, as the true in-situ processes generate permeability in the highly

Jan 9, 1980

By Clifford B. Farris

Introduction Shale Mining Problems The mining problems an oil shale operator will face are largely determined by the process. Candidate oil recovery processes are surface (above ground processing of mined oil shale), modified in situ (underground with some shale removed), and true in situ (completely underground with no shale removed). The shale removed for modified in situ (MIS) is generally processed by surface techniques. The mining problems are different for each category. Fig. 1 depicts the diversity of western shale deposits. Mining for surface operations will employ underground mining techniques in common use but the scale will be larger. A typical oil shale operation is expected to require 75,000 to 250,000 st (68 000 to 226 800 tons) a stream day of crushed oil shale. This is above the upper limit of current mining operations. Major problems in¬clude: (1) lack of good engineering design properties for oil shale, especially when interbedded with saline minerals at depths below 1,000 ft (305 m); (2) presence of water, hydrogen sulfide, and methane in some areas; (3) necessity for mine disposal of as much retorted oil shale waste as possible; and (4) control of en¬vironmental impacts of mining. Portions of the oil shale deposits in Colorado, Wyoming, and Utah and significant portions of the Devonian shales in the eastern U.S. are adapted to surface mining. No major technological problems are apparent outside overburden thicknesses up to 1,000 ft in the West. However, numerous political and environmental dif¬ficulties have arisen. One major oil shale developer cancelled a planned surface mining operation and currently is pursuing a modified in-situ plan. The eastern shales are closer to the surface than the western, but suffer from many of the same environmental and political problems. Modified in-situ operations face much more severe mining problems than surface efforts. Because the mined stope (called an in-situ "retort" by processors) acts as a retorting process vessel subject to gas flow, combustion, and temperatures between 1,500° and 2,000°F, mining is under highly restrictive limitations. This processing method involves removing between 20 and 40% of the shale deposit and then blasting the roof and walls into the mined space, where the oil is recovered by retorting. Major problems are: (1) swell factor severely limited; (2) need for consistent size distribution of blasted shale; (3) even filling of stope (in-situ retort) by blasted shale with consistent permeability throughout; (4) scaleup of blasting techniques, after optimization; (5) protection of retort pillars and roof during and after retorting; (6) prevention of groundwater percolation; (7)use of ANFO explosive in wet holes; (8) disposing of surface-retorted shale waste in stope; and (9) restoration of site. True in-situ operations are less well developed than surface or MIS processes. No actual mining is done, as the true in-situ processes generate permeability in the highly

Jan 1, 1980

By B. W. Cavender

"World-class manufacturing" (WCM) techniques can be applied in milling operations to substantially improve productivity and reduce costs. Through the use of "just-in-time" and "total quality control" practices, WCM methods establish an environment for continual and rapid improvement in all aspects of production operations, with particular gains in product quality, costs, flexibility, employee involvement, and responsiveness to customers. This paper examines WCM techniques that can be utilized specifically in the mill, and their influence on plant configuration, organization, and scheduling practices; equipment selection and maintenance methods; training; the role of supporting staff; and methods of data collection and analysis.

Jan 1, 1993