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By Peter J. Szabo

The mining executive works in a cyclical industry. His employment is subject to the vagaries of the marketplace. Boom and bust has always been the industry's story. "Big oil" failed in its mining effort. This left emotional and financial scars on many mining families. One must remember that mining executives always play a high-stakes game. Given the cyclical nature of the mining industry, mining executives need to take care of their own financial security. The mining executive that does not plan for his financial security in this cyclical business is playing Russian Roulette with his future. Take a look at those people who have reached their later years with the mining industry. One usually finds three categories of people. Those few in the first group have been fortunate enough to have worked for one company. They have survived the winnowing process of cyclicality, political problems, and takeovers. They have reached normal retirement age. For them, the retirement years are usually comfortable. People in the second group have worked for those same mining companies. But these people have been forced out by early retirement. Or they have been laid off for cyclical, takeover, or political reasons. The third group includes those who have held many positions in the mining industry. Probably not until their later years are they fully vested, if at all, in a pension program. The first small group, then, is the exception. The others, unless they have taken care of their financial security, are doomed to later years of financial problems, stress, and unhappiness. Too late in life, many realize the harsh realities of failure to plan and implement a personal financial program. Mining executives go to some of the world's leading mining schools, to learn how to make money. The curriculum is technically strong. Most mining graduates are familiar with the intricacies of discounted cash flow, present value, and the Hoskold formula. But few of these same mining schools require courses on personal financial planning. Such courses could give mining students a realistic foundation and the mechanisms with which to cope with their cyclical profession. An executive has only three sources of money. He can make money at work. He can put his money to work. Or he can get money from charities, such as government programs. Of these three sources of money, money at work has the best chance of providing financial security in later years. The mining executive must think of the day when he will be too old to work and contribute to the market place. At this point, the quantity and quality of his investments will determine whether his later years will be secure. Along with the Mining Engineering Handbook, two key books should be included in the mining executive's library. These are Venita Van Caspel's The Power of Money Dynamics and Benjamin J. Stein's Financial Passages. These books contain the basic concepts of personal financial planning so critical to an individual's financial survival. Venita points out the simple formula that is the key to financial independence: Time + Money + American Free Enterprise (Rate of Return) = Opportunity to Become Financially Independent Chart 1 shows that this is not a trite formula. The chart shows the dramatic effects of compounding over time. The chart also shows at various yields what a $2000 a year Individual Retirement Account (IRA) contribution will accumulate. Chart 1 (from Money magazine) is based on the future value of an ordinary annuity. It shows that the key to amassing a small fortune by the time a person reaches his 50s is starting to save methodically in his 20s. This, coupled with the highest yields consistent with safety of principal will ensure financial security. There are significant effects from compounding money over time. Every year the decision is put off to save for later years will cost a person dearly by the time he reaches his 50s. For example, consider the decision to put off for one year a $2000 IRA investment at a 12% return. Starting it at age 31 instead of 30 will cost the executive almost $100,000 by age 65. What if the executive waits until age 35 to get started with his $2000 a year investment? He will then lose nearly $400,000 by age 65. Stated another way, the executive costs himself this $400,000 simply because he did not invest $167 a month for five years. $167 a month - that's less than an inexpensive second car payment. This $400,000 pool of money could provide the executive a $40,000 a year income at age 65, assuming a 10% return on invest-

Jan 11, 1985

By H. J. Handewith

This paper explores the state-of-the-art of mechanical rock drilling and boring methods in use in the year 2000. It covers the basic mechanisms of cutting tool design and outlines the current understanding of related rock fracture methods. It provides suggestions for future research needs and discusses the mining and construction markets that are driving these needs.

Jan 1, 2001

By K. Saikiran, A. R. Nalla

Longwall management, regular shield maintenance, and evaluation of ground control problems can be performed using real-time shield monitoring program. Based on real-time shield pressure data, evaluation of intensity and interval of periodic weighting, estimation of time-dependent pressure increase and the effects of geologic anomalies can be obtained. In this study, full-face shield pressure data of over 457 m (1,500 feet) of face advancement is analyzed to evaluate shield response in the presence of surface lineaments, floor undulations, and multiple main roofs. Shield pressure increase due to web cutting is also correlated with setting pressure during periodic weighting and normal time. In addition, time-dependent pressure increase rate on Sundays and holidays is also correlated with time average pressure and the location of previous periodic weighting.

Jan 1, 2000

By R. L. Grayson, G. Mishra

Introduction Many old underground mines have been developed extensively into reserves requiring large numbers of workers to maintain and rehabilitate lengthy track haulages and/or belt conveyor systems. Often, large numbers of fans are required to maintain minimal airflows in areas where poor conditions and huge leakages prevail. Problems that beset one such coal mine and projects undertaken to restore it to potential profitability are presented. Brief history The Vesta No. 5 mine was opened in 1908. Drift development began near the Monongahela River, which was the primary avenue for shipping metallurgical coal to coke ovens in Pittsburgh. Over the ensuing 75 years, the main haulage entries were developed a distance of 16.1 km (10 miles) to the present mining area. Track haulage was used to transport coal from working sections to the river loading facility. As haulage distance and areas of high water influx increased, management decided, in 1973, to construct an underground conveyor belt system. The project spanned 36 months and culminated in a system of 22 flights, ranging from 205.7 to 1767.8 m (675 to 5800 ft) long. Six intake and eight return entries were developed as the mains were advanced. These entries provided adequate ventilating capacity over the years, but as extensive gob areas progressed and roof conditions deteriorated, the entries became inaccessible and more resistant to airflow. By 1981, five fans were being used to circulate 943.9 m3/s (555.5 cfm) of air through the mine. An average of 6440 t (7100 st) were produced from 20.8 continuous miner unit shifts and 2.7 longwall unit shifts each day in 1981. The ratio of support to production personnel was 1.94. To maintain the outby 16.1 km (10 miles) of haulage, 110 personnel were used. The average cost per ton was $43.54 ($39.58 per st), resulting in excessive bottom-line losses. The mine possessed a rather promising reserve, mostly in lease, of good quality, medium-sulfur metallurgical coal, but it also had a number of formidable operating problems. Operating problems Contributing factors toward relatively low productivity and high costs were the conditions of the track haulage, conveyor, and ventilation systems. Productivity was affected greatly by downtime associated with the conveyor system, which lacked adequate access for making splices or other repairs. Many areas within the conveyor belt entry itself required more

Jan 3, 1987

By K. Holmberg, D. Herriot

This paper by Mr Mclvor is yet another contribution to the eternal controversy surrounding the benefits, or otherwise, of high circulating loads in closed circuit grinding. Throughout the paper it is difficult to establish whether the author is referring to effects relating to the mill, classifier, or to the overall circuit. Table 1 is put forward as indicating the advantage of operating at high circulating loads. From the two (it would be interesting to see more) product sizing points provided in each case, the conclusions to be drawn are that cases one and two have very similar size analyses. The third case, however, indicates a much flatter curve, that is to say, higher fines production and a very wide spread of size ranges. If the objective of this circuit is to provide a closely sized product with minimum overground slimes to the downstream process, then it would appear to be the less "efficient" by far. No data is given for product pulp densities either. The term "efficiency" should never be used without a careful and clear definition. In this case, "efficiency" is used to express an apparent percentage reduction in operating work index (Bond) from the measured "standard" at 250% circulat¬ing load operation. The Bond calculation is itself based upon

Jan 1, 1989

By R. Addison

Boom, boom, boom, boom. The staccato beat rings out across the bush; the stamps are at work - slowly pulverizing gold-bearing ore for a patient, grizzled prospector. This is the State Battery near Marvel Loch - a tiny (capacity: 25 ton/day) gold plant operated by the Western Australian government. It is one of many such plants located in remote corners of Western Australia and the Northern Territory - miniature custom mills operated for the benefit of prospectors and small mine operators. These State Batteries, so called because they are operated by state governments and because the principal item of machinery in the plants are stamp batteries, are fascinating anachronisms: throwbacks to times long past, to a century ago, to the hard and heady existence of gold rush days.

Jan 1, 1986

By N. N. Clark, C. M. Atkinson

Pachuca tanks are used widely in the mineral industry for leaching and mixing operations. An analysis has been presented previously to predict circulation of homogenous slurry in Pachuca tanks with full height draft tubes. However, settling of solids causes deviation from the homogenous case. Circulation of settling slurry in a Pachuca tank is modeled and shown to be a function of settling velocity, solids fraction, solid and liquid density, air flew rate, and tank dimensions. The pressure balance is shown to be very sensitive to these parameters, especially at low slurry velocities. Equations for predicting the air requirements in Pachuca tanks containing settling solids are presented.

Jan 1, 1988

By Louis J. Trostel

Refractories, called the Hidden Industry by The Refractories Institute, provide the temperature and chemically resistant linings for the multitude of vessels that are used today in high temperature processes ranging from giant iron-making blast furnaces to industrial incinerators to petrochemical cracking units to the smallest furnaces used by the jewelry trade. While these refractory linings are absolutely essential to the proper functioning of these processes, the linings are almost always on the inside of the vessels and thus hidden from the eyes of the public. Refractories are defined in Standard C71 of the American Society for Testing and Materials (ASTM), titled "Standard Definitions of Terms Relating to Refractories," as "nonmetallic materials having those chemical and physical properties that make them applicable for structures, or as components of systems, that are exposed to environments above 1 000°F (538°C)." This criterion of ability to withstand exposure to environments above 538OC is the critical distinction separating refractories from other ceramics, fibers, and coatings applicable only at lower temperatures. In addition to resisting temperature, the refractories must with- stand abrasion, chemical and slag attack, resist thermal shock, and carry sustained structural stresses at high operating temperatures for as long as years. The most common methods of classifying refractories are by forming method and composition. First are the traditional formed and fired bricks, batts, and the associated multitude of special shapes. These refractories are usually formed at room temperature, dried, and then fired to high temperatures to develop the final properties desired. Other formed refractories are chemically bonded or resin or tar bonded. To complete the formed refractory matrix, some fired refractory bricks and shapes are subsequently impregnated with resins or tars. Physical dimensions of these formed refractories are classified into two general categories: standard sizes and special shapes. The standard sizes are those in common usage in the United States described in ASTM Standard C909 "Dimensions of a Modular Series of Refractory Brick and Shapes" based on the 38 mm basic module as described in ASTM Standard C861 "Determining Metric Dimensions of Standard Series Refractory Brick and Shapes." The most common size is the "9-inch straight" 228 x 114 x 64 mm (9 x 4 ½ x 2 ½ in.) of the "2 ½ -inch" series or 228 x 114 x 76 mm (9 x 4 ½ x 3 in.) of the "3-inch" series. Bricks of nonstandard sizes are referred to as special shapes. Their use is required in specific furnaces for particular requirements or applications. In addition there is the large and growing group of refractories sold as unshaped mixtures that may be formed into their final shapes at the application site. These unshaped mixtures are sometimes referred to as specialties. The mixtures are prepared to be hydraulically cast, plastic or wet rammed, dry rammed, or dry vibrated into their final shapes. Some are designed to be projected through nozzles (or gunned) onto their forms. The refractory mortars used to lay up the shaped refractories fall into this group referred to as specialties. Prepared refractory grains also are sold. These are usually calcined or fused materials that are subsequently crushed and sized to a variety of specific carefully controlled grain sizes or size distributions. These grains include calcined fire clay, dead burned magnesite, periclase (fused magnesia), dead burned dolomite, kyanite, tabular and fused aluminas, fused zirconia, fused mullite, and calcined alumina-magnesia spinel. The primary composition groups of refractories are the 1) alumino-silicate refractories made largely from fire clay and high- alumina materials, 2) silica refractories made from quartzites and ganisters, and 3) basic refractories from magnesia (or magnesite) and chromia (also referred to as chrome ore), alone and in combination, and dolomite. Special refractories include carbon, zirconia, zircon, high purity alumina, mullite, silicon carbide, silicon nitride, and some borides. In addition there are groups of special insulating refractories.

Jan 1, 1994

By Scott D. Thayer, George H. Milly

INTRODUCTION Ambient concentrations of radon and its daughter products have been measured and analyzed by a number of investigators for a variety of purposes. Principal among these purposes have been: (1) descriptive, to characterize the distribution and changes in concentrations under various conditions; (2) research in the use of radon as a tracer gas in the study of atmospheric characteristics and motions, such as eddy mass transfer, diffusivity profiles, large scale circulations, and the like; and (3) the use of radon as an atmospheric tracer in exploration for uranium deposits.* This information forms the basic data for this paper and for its placing the ambient natural, or non-anthropogenic, radon concentrations into the perspective of ambient radon health standards and lung cancer risk calculations. To enable better understanding of some aspects of the ambient radon data, review and analysis is also performed on selected measurements of radon emanation or flux from the surface of the earth into the atmosphere. These measurements have generally been made for purposes similar to those for ambient radon, i.e., (1) description of radon emanation characteristics; or (2) to support and justify the use of ambient concentration measurements in atmospheric research; or (3) in exploration for uranium. Interest is also developing in the use of such measurements for earthquake prediction. In addition, to complete the perspective, brief examination is given to anthropogenic ambient and flux radon measurements related to the mining and milling of uranium, so that comparison can he made with the values from natural sources. As a frame of reference we cite here previous summaries of studies which have presented representative values and ranges of ambient concentrations and emanation rates. H. Israel, in the Compendium of Meterorology (1951), cites eight studies of ambient radon concentrations which we have selected as representative of non-anomalous continental values. Their means generally range from [0.06 to 0.15 pCi lit-1 with the smallest reported minimum of zero and the largest maximum 0.53 pCi lit-1. The overall mean is 0.10 with a standard deviation of 0.03 pCi lit-1. Means over oceans are much smaller, and the data scarcer, with only three values ranging from 0.0004 to 0.003 pCi lit-1 and a mean of 0.0016 pCi lit-1.] Thirteen studies from Israel's list were selected as representative of mountainous terrain. These data, except for the cases of higher elevations, frequently show significantly higher values than the average cases in non-mountainous terrain described-above. The averages range from 0.10 to 0.59 pCi lit-l; the smallest minimum is zero and the largest maximum is 9.2 pCi lit-1. The overall mean is 0.30 with a standard deviation of 0.17 pCi lit-1. Israel also cites five studies of radon emanation (flux) from the earth's surface. These show a mean of 0.40 pCi-2m-2 sec-1 and a range of from 0.21 to 0.74 pCi m-2 sec-1. Data on flux are naturally scarcer in the literature than data on ambient concentrations, because of the greater interest in and utility of the ambient information. In this paper we also give special consideration to observations of the variability in time and space of radon flux rates, and to the impact of these phenomena on the use of such data for a variety of purposes. NATURAL(NON-ANTHROPOGENIC)AMBIENT RADON CONCENTRATIONS We have examined the following reports for the data selected for this category; these studies were generally intended to describe radon characteristics in the atmosphere. Jonassen and Wilkening (1970); Bradley and Pearson (1970); Wilkening (1970); Lambert, et al (1970); Pearson and Moses (1966); and DickPeddie, et al (1974). Another set of studies which was reviewed was selected because the investigators made ambient radon measurements in the course of examining the use of radon as a tracer in atmospheric research. This set consists of: Israel and Horbert (1970); Carlson and Prospero (1972); Subramanian, et al (1977); Larson (1978); Cohen, et al (1972); Hosler (1966); and Shaffer and Cohen (1972). Finally, unpublished data from uranium exploration activities (Milly and Thayer, 1976) was analyzed. [Treating the ocean cases first, the mean values are generally consistent with those quoted earlier from Israel (0.0004 to 0.003 pCi lit-1); they range from 0.001 to 0.011 pCi lit-1, with 0.003 the most frequently reported value. Continental values, from eight studies, range in means from 0.07 to 0.41 pCi lit-1 (not including mineralized areas, or "uranium country", discussed later), with maxima as high as 2.4 pCi lit -l. For comparison, the means from Israel are 0.06 to 0.15 pCi lit-1, with a maximum of 0.53 pCi lit-1. Some of these studies also present the typical decrease of-1 concentration with height to 0.01 to 0.04 pCi lit at 5 to 7 km. The vast numbers of uranium prospecting radon data of]

Jan 1, 1981

By S. Tafazoli, D. Cooper, I. Bell, S. Nouranian, B. Sameti, M. Ramezani

"Image-based rock fragmentation sensing in mines and quarries includes an important rock boundary delineation step, commonly referred to as rock segmentation. This paper presents an artificial intelligence-based solution to this challenge. The proposed technique encodes prior knowledge of previously analyzed images into mathematical/statistical models. Human-labeled images are used as inputs to train neural networks through an optimization process. The networks can then be used in real time for rock delineation. To build the models, special deep artificial neural networks are used as a pixel classifier. The proposed classifier labels each pixel (edge, rock or fine) by analyzing a plurality of pixels within the image. Advances in machine learning allow the network to contain many parameters. The increased number of parameters is a strong factor in the classifier’s ability to correctly classify each pixel. Deep learning-based segmentation, combined with 3D imaging followed by post processing, provides a unified fragmentation sensing solution. Results from automatic segmentation are compared to human labeled segmentation using the percentage passing curves for 64 rock images. INTRODUCTION Mines and quarries can see significant productivity and performance benefits by controlling material sizes (McKee, Chitmobo, & Morrell, 1995; Sellers & Gumede, 2012). During the past decade, image-based fragmentation analysis has been applied to estimate rock size distributions in order to optimize procedures in mines and quarries. Using a roving camera and operator assisted analysis Maerz, Franklin, and Coursen (1987) measured the size distribution of the blasted rock and eliminated the need for manual sieve analysis. Since then, many others have introduced automated and manual methods for fragmentation analysis and improved upon existing approaches (Girdner, Kemeny, Srikant, & McGill, 1996; Smith & Kemeny, 1993; Palangio, Palangio, & Maerz, 2005; Tafazoli & Ziraknejad, 2009; Raina, 2013). In image-based fragmentation, rock boundaries are identified in the image, and an image scaling is applied to transform rock pixel sizes into real world dimensions. Usually geometric references, such as regularly shaped objects (discs and basketballs) (Siddigui, Ali Shah, & Behan, 2009), or the known size of an excavator bucket (Zeng, Chow, Baumann, & Tafazoli, 2012), are used to determine the proper scaling factor. In recent years, 3D imaging and sensing have also been incorporated to improve rock delineation. Specific methods include using camera-laser combinations and stereo imaging to measure rock fragmentation on conveyor belts (Noy, 2013; Thurley, 2013; Dislaire, Illing, Laurent, & Pirard, 2013) as well as portable fragmentation analysis devices with 3D imaging sensors (Sameti, et al., 2014)."

Jan 1, 2018

By Frederick S. Fisher

Three spatially separate porphyry copper/molybdenum deposits are associated with the Tertiary Needle Creek igneous center in the southern Absaroka Mountains, Wyoming. In all three deposits a central zone containing disseminated copper and molybdenum is surrounded by a halo of small, discontinuous base and precious metal veins. Propylitically and phyllically altered rocks are common in all three mineralized areas, and potassically altered rocks are locally present. Fission- track age data from apatite and zircon indicate that mineralization occurred about 32-40 m.y. ago. Limited data suggest that the lead isotopes are nonradiogenic, similar to porphyry copper deposits elsewhere in the western United States. The complex igneous history of the Needle Creek center has involved several periods of intrusive and probably extrusive activity. lntrusive rocks are calc-alkalic and include andesite, granodiorite, diorite, quartz monzonite, dacite, and rhyodacite. Stocks (1-30 kmz in exposed area), radial dike swarms, and sills make up the presently exposed plutonic masses and constitute lower-level vent fillings in an old stratovolcano. The Needle Creek igneous center is located approximately midway along a northwest-trending belt of intrusive rocks extending more than 100 km along the central axis of the Absaroka volcanic field. The igneous and mineralized centers within this belt were probably localized at the intersections of northwest- trending Laramide and possibly Tertiary fracture systems and earlier northeast-trending Precambrian structures in the underlying basement rocks.

Jan 1, 2013

By D. Zaharaki

In the present experimental study the geochemical stability of inorganic polymers was studied by immersing them in various solutions (distilled water, seawater and 0.5N HCl) for a period of 7 months. Inorganic polymers were synthesised by mixing ferronickel slag with kaolinite, potassium hydroxide and sodium silicate solution. The cement like paste was heated at 80 °C for 48 hours and left for curing at room temperature. Their structural integrity was assessed by compressive strength testing after subjection to freeze-thaw cycles as well as high temperature heating. XRD studies were carried out in order to identify new formed phases and provide useful information regarding the progress of the mechanisms involved.

Jan 1, 2008

By Edward T. Koch

With the dramatic increase in world demand for basic raw materials, open pit mining is proceeding at an unprecedented rate. A viable demand is the ever tempting Siren's song for increased production or new facilities. When the Siren's lure is viewed against the panorama of today's world economic milieu the concomitant Scylla and Charybdis are seen in the form of high capital cost and high operating cost. If the economic realities of present day open pit mining are to show a proper return on investment, a clear and penetrating eye must be cast upon the area of mine planning. This paper deals with the problem of overburden removal. In almost every open pit mining operation overburden removal is a significant part of the capital cost and operating cost of the total operation. This paper deals with a new and unique method to affect economical overburden removal. Well known to all are the parameters surrounding draglines, shovels, and bucket wheel excavators. All of these machines require a reasonably stable soil to support them and the shovel and bucket wheel excavator require a reasonably stable bank in which to operate. Their reliability, portability and rate of production per dollar of invested capital are good.

Jan 1, 1975

By D. P. Patil, B. K. Parekh

Water is the mainstay for beneficiation of fine size coal and minerals; however, it is also the least desirable constituent in the final product. The basic concept of the novel process described in this paper is based on the differential surface heat absorption capacity of individual particles, which differs for different species of mineral. When a mixture of fine material is exposed to a radiant energy source, the various solids components present in the mixture will absorb heat energy depending on their composition and there will be difference in the surface temperature of the particles. When this differentially heated solid mixture is placed on a moving belt, which is coated with low temperature melting resin, the hotter component of the mixture will stick to the belt and relatively cooler will stay free on the belt and fall off at the end of the belt run. Experiments were conducted with pyrite, coal and quartz of 6 x18 mesh particle size. The goal of the test program was to find the optimum conditions at which there exists a required temperature difference between minerals and coal particles by controlling the operating and system variables. Preliminary tests results showed that there is a potential for separating mineral matter from coal using the thermo-adhesive separation technique.

Mar 2, 2022

By K. W. Lee, C. Pound, J. Carmody, L. Petersen, C. Nelson, J. G. Cai

The feasibility of developing the Underground Science City below the Kent Ridge Park has been investigated. The primary aim of the study has been to explore the possibility of creating underground space to house a new community of research laboratories and offices. The investigation represents the first such study undertaken in Singapore for a non-military underground facility. The paper describes the geology of the Underground Science City site and illustrates the layout and plan of the Underground Science City. The geology and rock mass below the Kent Ridge Park is generally favorable for the development of an underground cavern complex. Underground Science City can be potentially developed housed in a cavern complex. Several potential development schemes are studied; with various combination of deep/shallow mined caverns of different span sizes and access options. The preferred scheme is shallow, mined room-and-pillar caverns with large spans and shaft accesses at both existing surface Science Park 1 and Science Park 2. The scheme can be potentially expanded laterally to create more underground space for new Underground Science Cities at Kent Ridge area.

Jan 1, 2001

By Edwin K. Maughan

The Rocky Mountain region contains part of the paleocontinental shelf that lay in Arizona and New Mexico through Utah, Colorado, and Wyoming into Montana and North Dakota. The shelf was bounded by the northeast-southwest-trending Transcontinental arch and the Cordilleran miogeocline in late Paleozoic and early Mesozoic time. Major tectonic features that affected middle Phanerozoic sediments on the shelf were the Big Snowy trough and Williston basin in the north and the ancestral Rocky Mountains in the central part of the region. The Zuni uplift and similar positive areas occurred along the axis of the Transcontinental arch in the southern part. The late Paleozoic and early Mesozoic sedimentary rocks record transgressive-regressive marine cycles in which the Cordilleran shelf and much of the adjacent craton were inundated by epeiric seas. Early in the Carboniferous, an epeiric sea covered most of the shelf. Greater topographic relief developed in Late Mississippian, was at a maximum in Middle Pennsylvanian, and then diminished through Permian and Triassic time. The development in the Pennsylvanian Period of horsts and grabens along northwest- trending faults on the northwest flank of the Transcontinental arch resulted in the ancestral Rocky Mountain system. The eastern part of the region was emergent by Middle Triassic, and the emergence lasted until Middle Jurassic, owing to uplift along the Transcontinental arch. During the early part of the Mesozoic, the sediments were dominantly terrigenous and were deposited mostly in shallow littoral marine environments shifting to continental. Most middle Phanerozoic structural elements within the area of the shelf are characterized by lineaments that have either an east-northeast or a conjugate north-northwest trend. The east-northeast lineaments closely parallel the northeast trend of the continental slope (miogeocline) in Nevada to southern Idaho. The conjugate set closely parallels the northwesterly continuation of the miogeocline north of an approximately right- angle bend in south-central Idaho. The northeasterly trending Transcontinental arch and the northwest-trending margin of the Canadian Shield are parallel structural elements with the north- east and northwest trends of the miogeocline. The rectangular lineament pattern on the shelf suggests a system of rectilinear fractures within the underlying Precambrian crystalline basement rocks that moved several times in the Phanerozoic in response to external forces applied against the continental crust. Movement of these blocks influenced erosion, deposition, and lithofacies of the sediments in middle Phanerozoic time. Zones of crustal weakness, represented by the lineaments bounding these blocks, probably were influential in localizing sedimentary mineral accumulations and petroleum deposits, as well as later igneous intrusions, volcanism, and emplacement of hydrothermal ores. Igneous activity in this region was rare during the middle Phanerozoic, but these conjugate fractures seem to have been avenues for later passage of hydrothermal solutions responsible for ore emplacement.

Jan 1, 2013

By Zengwu Zhao, Peng Xu, Jieliang Wang, Qingwei Bai, Xinyang Liu, Xiao Lei

The paper investigates the capture and recovery of rare earth minerals from Bayan Obo ore using superconducting magnetic separation. A finite element model (FEM) was established to study the influence of various factors on the capture of rare earth minerals under a high-gradient superconducting magnetic field. The study aims to improve the efficiency of rare earth mineral separation and recovery.

Oct 1, 2023

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 C. J. Milam

Oil shale may not produce the same excitement of the gold rush days, but presently there is an "oil shale fever" among mining men. Such exotic equipment as 800-ton haul units, 75 ft. boring machines, and huge fully automatic multi-purpose jumbo drill units are only a few of the topics of conversation in the oil shale groups. I am dreaming, perhaps, but this type of exotic thinking will exuberate the advancement in mining technology and will only be tempered by the practicality and the availability of today's equipment.

Jan 1, 1975

By James R. Arnold

Gold Fields Mining Corporation started processing ore from it's Chimney Creek operation in northern Nevada in November, 1987. Since that time production has averaged about 200,000 ounces per year from the milling and dump leaching circuits combined. The events that led up to commissioning of the plant started in January of 1985 when the Gold Fields exploration team drilled their first hole in an area now known as Discovery Hill. The major orebody was located later in the year in what is currently the major focus of activity, the North Pit. Subsequent drilling since plant startup has found another 14 million tons of ore two miles south of the original orebody. This South Pit orebody is currently being stripped and metallurgical testing is underway. Engineering Engineering on the Chimney Creek plant started in earnest in May, 1986. Davy McKee Corporation from San Ramon, California, did both the engineering and the construction management. Before engineering began the entire senior staff of the Plant Department was hired and assigned to the project. Senior staff included the Plant Superintendent, Plant General Foreman, Maintenance General Foreman and Chief Metallurgist. Gold Fields does not employ an internal central engineering staff to design their plants. We feel that the people who design the plant should be the ones who will be required to run it once it has been commissioned. This philosophy affords a continuous accountability from start of design through commissioning and operations. All four of the senior staff spent the most critical phase of the engineering stage at Davy McKee, so the plant is truly a reflection of all four disciplines. In bringing on the Maintenance General Foreman from the start, there was a focus placed on ease of maintaining the plant. Another philosophy that was adopted from the start was that the plant be easy to work in and maintain for both operators and maintenance personnel. Numerous design criteria were given to Davy McKee to ensure this. For example, we required that every piece of equipment could be reached easily with a crane or fork lift. All conveyors were required to have walkways on both sides for ease of maintenance and a minimum of 30 inches of clearance under them for ease of cleanup. Visibility for operators was considered very important and the control rooms and general plant layout were designed with this in mind. A list of about 100 general rules were given to Davy McKee during the early layout meetings and these were held as the general design criteria throughout engineering and construction. While engineering was progressing in San Ramon, California, dump leach test work was being done at the site. Three 6 foot diameter fiberglass columns were constructed and filled to a 20 foot height with low grade ore. Leaching characteristics were determined and the dump leach design was based on information collected from these columns. Construction The major contractors on the project were The Industrial Company for the bulk of the piping and structural, EMKO on the electrical/ instrumentation and Hunewill for most of the earth work and leach pad construction. All plant operating and maintenance personnel were employed eight weeks before startup for intensive training. Instructors were Gold Fields personnel, including foremen, and Davy McKee engineers. On occasion, selected suppliers representatives were brought in to discuss major pieces of equipment. Project completion was targeted for January, 1988 at a projected cost of 78.9 million dollars. Actual startup was about 1 1/2 months ahead of schedule and slightly under budget. Full design capacity was achieved the first full month of operation. Crushing Run of mine ore is delivered to the crusher and dumped into a 90 ton hopper which is topped with a 30" X 30" opening stationary grizzly. Ore is fed to a 50" X 60" Telsmith jaw crusher with a 5' wide apron feeder. The closed size setting of the

Jan 1, 1989