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By D. D. Harbuck

Previous studies at the U.S. Bureau of Hines have shown that only 70 to 80% of the germanium in domestic zinc process residues can be extracted during H2S04 leaching. To increase germanium extraction, the Bureau developed and researched the hypothesis that minor amounts of germanium and zinc silicate, both present in zinc calcine, dissolve during the leaching stages of zinc processing, forming soluble germanium and silica gel. This silica gel then selectively adsorbs germanium from solution, rendering the germanium insoluble. Testing showed that as the amount of silica gel formed increased, the amount of insoluble germanium in the zinc residue increased. Several processing alternatives are presented for overcoming this problem.

Jan 1, 1991

By B. J. K. Sullivan, Brian Hornsby

INTRODUCTION Mount Isa Mines Ltd. operates a copper and silver- lead-zinc property at Mount Isa in northwest Queens- land, Australia. Mount Isa is located in the tropics at latitude 20°43'S and longitude 139°30’E (Fig. 1). It is on the upper watershed of the Leichhardt River and at an elevation of 365 m above sea level. The average rain- fall is 360 mm/y, the greater part of which falls in January to March (the hot summer months). The mean summer temperature for these months is 30°C (dry bulb), with a maximum temperature of 43°C; the mean wet bulb temperature is 25°C with a maximum of 28°C. Mount Isa is located geologically towards the western edge of the Precambrian Shield of northwestern Queensland. This complex forms a north-tilting dissected peneplain which extends in the north-south direction for 640 km, with widths varying from 32 km to 190 km. The combination of differential erosion, regional strike, and steep dips has produced a corrugated topography of low north-south orientated hills and valleys. The field was first discovered in 1923 as a silver- lead-zinc field. Mount Isa Mines Ltd. was formed the following year and subsequently became the sole operating company on the field. Lead and copper ore have been mined and treated separately and simultaneously at Mount Isa since 1953. Intensive exploration commenced in 1954 and an active exploration program provided the justification for a series of production expansion programs in both silver- lead-zinc and copper (see Table 1 ). The most recent and largest production expansion program at Mount Isa commenced when a decision was reached in December 1969 calling for an increase in copper production from 100 000 to 150 000 t/y of blister copper. A major factor which influenced this decision was the substantial additions to the ore reserves in the so-called 1100 ore body which is a massive copper sulfide ore body with a known strike length of approximately 2500 m, a height which is variable up to 300 m, and a width of generally 300 m up to a maximum of 370 m (see Figs. 2 and 3). Host to the copper mineralization is a complex and variable rock generally called "silica dolomite." The ore body strikes 6.02 to 6.1 rad (345° to 350°), dips west between 0.78 and 1.13 rad (45° and 65°), and is truncated at depth by fault implaced basement rocks. It first occurs some 600 m below the surface and bottoms at about 1000 m below the surface. The unconfined compressive strength of the silica dolomite ore varies from 150 to 250 MPa, whereas the basement rocks, carbonaceous mylonite, slaty shale, buck quartz, and greenstone (a chloritic schist) are considerably weaker, varying in strength from 20 to 80 MPa. The distribution of mineralization within the ore body is variable, but can be considered as generally high grade at or just above the basement contact and diminishing towards the upper reaches of the ore body. The current

Jan 1, 1982

By Robert M. Stevens, Arnoldo Acuña

INTRODUCTION In the early 1950s, underground miners and tunnel¬ing contractors were experimenting with ways to supple¬ment or eliminate track-bound loading and hauling equipment. Diesel-powered crawler and rubber-tire mounted front-end loaders and trucks designed for use on the surface were being modified and tried with limited but encouraging success. Miners began working with interested manufacturers to explore the develop¬ment of vehicles specifically designed to meet the de¬mands and constraints of underground material han¬dling. By the mid 1960s, load-haul-dump (LHD) vehicles were firmly established as a fundamental part of what has become known as the "trackless" mining concept, used in many mines and many countries around the world. The flexibility, mobility, and versatility of these units have given the industry a useful tool and have added new dimensions to mine development and produc¬tion. Many old mines have been redesigned to accom¬modate these trackless vehicles, and few new mining plans have failed to find some use for the concept during some phase of development and production. By 1977, several manufacturers in several different countries were producing a variety of LHD vehicles to meet the growing worldwide demand. GENERAL DESCRIPTION LHD vehicles combine certain characteristics of conventional front-end loaders and dump trucks, spe¬cifically designed for materials handling in underground mining and tunneling. The design intent is to provide one vehicle with one man, with the vehicle loading itself, hauling the load over level or inclined haulageways, and dumping the load. A typical production cycle of the most popular units has the operator driving the vehicle forward, forcing the bucket into the muck at or near floor level, and using the tractive effort of the vehicle and the prying action of the bucket to roll out and tilt back the load as shown in Fig. 1. With the bucket rolled back into the carrying position on the boom and the boom resting on the main frame of the vehicle, the load is hauled (trammed) to the dump point as shown in Fig. 2. At the dump point, the boom is raised, the bucket is rolled forward, and the load slides out as shown in Fig. 3. After dumping, the bucket is rolled back to the carrying position, the boom is returned to rest on the main frame, and the unit is driven back to the loading point for another load. There are two other types of LHD units that are slightly different in the cycles that they perform. One uses a hopper arrangement carried on the front of the machine, with a small bucket mounted ahead of the hopper. Several passes with the small bucket load the hopper, which is dumped by opening its floor. Al¬though this concept is several years old, it has gained less than 0.5% of the total market. The most recent LHD concept differs in that it has one bucket nesting inside another. The smaller inner bucket is loaded first, and it is then tilted back and above the larger bucket. When the larger bucket has been loaded, it is rolled back, and the total load is trammed to the dumping point. The dumping operation tilts the buckets in the reverse order from that of the loading operation. The impact of this new concept on the mining industry has not been measured yet. This chapter concentrates on the LHD vehicles employing the cycle described by Figs. 1 through 3, since these LHD units constitute an estimated 99% of the units in current use. MAIN VEHICLE FEATURES In general, the LHD vehicles available from most manufacturers share the same basic features.

Jan 1, 1982

By G. Rinelli, Arthur F. Colombo, Donald W. Frommer

With the opening of the Tilden mine near Ishpeming, MI, a new era in iron ore beneficiation was begun. A description of a U. S. Bureau of Mines investigation is summarized to illustrate the selective flocculation-deslime-flotation process developed by the Bureau and used at the Tilden concentrator, which is also briefly described. The operating parameters for the selective flocculation-cationic flotation of an oxidized taconite from the Mesabi range are discussed. A water reclamation system using lime and a cationic flocculant was applied to reclaim the effluents from a 900-pound-per-hour flotation pilot plant. About 80 percent of water requirements were recovered, and the calcium content of the reclaimed water was found to be more important than clarity in influencing the selective flocculation and flotation processes. Although reclaimed waters with about 10 ppm calcium registered turbidities of approximately 5,000 ppm SiO2 equivalents, the concentrates produced using these waters contained 64 percent Fe and =5.0 percent SiO2 and had accompanying iron recoveries of 75 percent. Lower grade concentrates resulted from using reclaimed water with higher calcium contents and lower turbidities.

Jan 1, 1976

By E. L. Mann, Robert L. Virta

Asbestos is a generic name given to six fibrous minerals that have been used widely in commercial products. The six types of asbestos are chrysotile, crocidolite, amosite, anthophyllite asbestos, tremolite asbestos, and actinolite asbestos (Table 1). Chrysotile is the asbestiform variety of serpentine. Crocidolite, amosite, antho-phyllite asbestos, tremolite asbestos, and actinolite asbestos are the asbestiform analogues of riebeckite, cummingtonite-grunerite, anthophyllite, tremolite, and actinolite, respectively. Although amosite is an acronym for the Asbestos Mines of South Africa (AMOSITE) and does not specify a mineral type, it generally is composed of cummingtonite-grunerite asbestos so the terms are assumed to be synonymous.

Jan 1, 1994

By Aditya Rana, A. K. Mishra, M. M. Singh, N. K. Bhagat

Many cases of derailments, train accidents and traffic interruptions due to the slope failure and rockfall have been reported in the past on Konkan Railway trackline because of unstable rock slopes. The authorities installed stability enhancement measures such as wire netting, rock bolting and shotcreting which were found insufficient. The failed geotechnical measures prompted authorities to excavate the unstable slopes. Rock blasting is generally not preferred for the excavation of slopes along the transportation route. Stabilisation and widening of slopes by blasting need closure of the route for a considerable time. Discontinuing traffic on Konkan Railway route was undesirable as it connects two important port cities Mumbai and Mangalore. The paper presents an innovative directional controlled blasting (DCB) technique for excavating three unstable slopes (i.e. cuttings) in hilly terrain without disturbing the traffic. New empirical formulae for small geometry blasting to estimate burden and throw have been developed. A unique sequence of firing and excavation with powder factor varying between 0.04 and 0.39 kg/m3 irrespective of the actual free face was used for rock blasting. The process controlled the throw of blasted material over the track and resulted in a smooth and stable wall. The slope angle has been changed from 80 to 82° to 45–47° and probability of wedge, planar and toppling failures was eliminated. About 100 such accident-prone slopes (52 km cumulative length, 7% of total route) situated at discrete locations along Konkan Railway route were stabilised using the technique. No incident of rockfall and slope failures along these slopes has been observed after the stabilisation.

By D. R. Babich, E. R. Bauer

Noise-Induced Hearing Loss (NIHL) continues to be a concern of the mining industry. A new noise standard (30 CFR, Part 62) is aimed at reducing NIHL in mining through engineering and administrative noise controls. However, the difficulty and expense of implementing engineering controls can make administrative controls an attractive alternative for reducing worker noise exposure. Over the last three years, the National Institute for Occupational Safety and Health (NIOSH) has conducted worker noise exposure surveys in underground and surface coal mines and coal preparation plants. The surveys revealed numerous possible administrative controls and an approach to implementation and analysis. The surveys have shown that worker dosimetry, time-motion studies, and equipment noise profiling are important aspects of effectively utilizing administrative controls. A description of the approach for selecting, implementing, and evaluating administrative controls, and a list of administrative controls, are reported.

Jan 1, 2004

By Donald E. Warnken

The Study concerns the estimation of fair market value (FMV) of non-producing mineral rights. Two approaches to value are used and the values determined by each are compared. The Study area environment is unusual. The tectonics is visible on surface rocks throughout much of the study area. The effect on mineral values in the exposed areas has been compared to areas where the tectonics is not visible.

Jan 1, 2005

By Ed L. Schrader

Kaolin of the Georgia-south Carolina "Clay Belt" are used in a wide variety of filler and extender applications. Sane applications specifically require the performance enhancement delivered by incorporating kaolin into the product formulations. Other applications are less specific in requirements for an inert mineral filler. In order to be a feasible candidate for filling and extending, a mineral or mineral product must be generally inert (except where specific interaction with the filled medium is desired), inexpensive, easily handled and transported in a variety of forms, accessible to a broad segment of the desired market, and must exist in sufficiently large ore reserves as to assure production for many years. Of course, more precise requirements are necessary in specific applications of a prospective filler material.

Jan 1, 1985

By R. H. Grau

The National Institute for Occupational Safety and Health (NIOSH) has conducted research to improve the ventilation of large-opening mines. The research has demonstrated that the ventilation of large-opening mines improves significantly by including ventilation requirements in the mine planning process and implementing some practical techniques during mining. Planning the location of long pillars to reduce the number of crosscuts between intake airways and return airways, positioning auxiliary fans in their proper locations, and establishing ventilation stoppings with minimal leakage all significantly improve the ventilation of large-opening mines. Mine operators that adopt these techniques in the mine ventilation plan will reduce mineworkers? exposure to airborne contaminants.

Jan 1, 2008

By S. K. Kawatra, Harrison R. Cooper

In the last 30 years, on-¬stream slurry analyzers have proven to be of great use in the control of mineral processing circuits. This review discusses the two most popular methods, x-ray fluorescence and neutron activation analysis, and also considers techniques which are still under development.

Jan 1, 1986

By S. Vogely, J. Trescot, D. Connor, F. Beloy

In 2001, the Minntac Division of US-Steel retrofitted one of their Grate-Kiln Iron Ore Pelletizng lines with a Ported-Kiln Air Injection System (PKAIS) the first of it’s kind in the world for oxide pellets. The Ported Kiln System injects air under the bed of pellets in the rotary kiln, causing rapid oxidation of the magnetite pellets. This rapid oxidation allows for lower kiln temperatures, reducing fuel demand; less heat load on the annular cooler; and higher pellet quality. Both the process and the equipment are patented developments by Metso Minerals. This paper discusses the process, the key equipment, and the benefits to the pellet plant and the downstream blast furnace operations.

Jan 1, 2004

By Frank L. Gaddy

Falls of roof account for over 50% of the fatalities that occur in coal mines in the US. Thus, roof control is one of the more important phases of underground mining. In reality, the control of roof influences the system of mining and is a major determinant of the width and spacing of working places, operations at the mining face, ventilation control, and surface subsidence. Frequently, the control of roof is the largest single cost item. Roof control is a never-ending task, not only at the working face and throughout sections where men are working, but along haulways and air- ways that must be maintained for the life of the mine. This is because roof, even the best of roof, slowly deteriorates, so it must be frequently examined, with corrective support applied when needed. As coal is excavated, stresses are set up in the roof because the previous equilibrium is upset, resulting in pressures that cause fractures and slight movements that are frequently hard to detect. Unless the immediate roof, in the excavated area, is given support by artificial means, it might fall or there might be a succession of falls, varying from a thin scale to several feet, depending on the nature of the top. Exceptions to this are those rare mines, or sections of mines, with hard, strong, nonweathering roof that requires no support.

Jan 1, 1981

By Marian Radetzki

The economic developments and industrial behavior patterns that led to a lasting excess capacity in the world non-ferrous metals industries from the aid-1970s are explored. Detailed attention is devoted to analyzing and defining crucial concepts like "capacity", "excess capacity", "capacity maintenance" and "investments". Empirical evidence of capacity utilization and capacity growth in the industries under study is provided. The coincidence of excess capacity and low prices on the one hand, and investments in capacity maintenance and capacity expansion, on the other, is seen as a consequence of substantial declines in the metal industries' investment and production costs during the period studied.

Jan 1, 1989

By Dennis S. Kostick

Sodium is a silver-colored metal that is so unstable that it reacts violently in the presence of water, and chlorine is a greenish-colored gas that is dangerous and lethal. Yet the combination of these two elements forms sodium chloride, commonly known as salt, which is a white-colored compound essential to life itself. Salt is perhaps the only mineral in the world that is used virtually by every human being in every country. Although its importance has diminished over time, salt has had a profound influence on history. Sources of salt have determined the location of cities, such as Salzburg, Austria, Salzgitter, Germany, Salt Lake City, UT, and Saltville, VA. Populations have migrated in search of salt, and wars have been fought to obtain or to protect it. Although there is no written record of when prehistoric man first discovered salt, he probably instantly appreciated its unique and distinctive taste and sought more of it. He noticed animals were attracted to salt springs and salt licks, where they satisfied their innate cravings. Man used this knowledge to hunt for food; where he found the salt, he would find the animals. Because prehistoric man was not aware of his physiologic need for salt, he automatically received his salt requirements from the meat of the animals he ate. A Mesopotamian tale tells of a wounded pig that ran into the ocean and drowned. After being recovered from the ocean, where it was saturated in the salt brine, the pork was found to taste better than unsalted meat. It was not until man graduated from a nomadic to an agricultural society when he introduced vegetables and cereals into his diet that he realized he needed additional supplements of salt. The Sumerians ate salted meat and used salt to preserve food about 3500 BC. In approximately 1000 BC, the Trojans learned to use salt for preserving fish. The maritime civilizations, such as that of the Phoenicians, engaged in an extensive salt trade throughout the Mediterranean. Many superstitions, customs, and traditions surround the religious, social, economic, and political aspects of civilization. Although some commodities have provided the basis of some ageless metaphors and cliches (i.e., heart of gold, strong as steel, etc.), none are more commonly used than those pertaining to salt. Being "the salt of the earth" referred to a person's worthiness, as referenced in Matthew 5:13 of the Bible. Someone "not worth his salt" reportedly was used in ancient Greece in bartering salt for slaves. When a laborer was worth his salt, he was paid a salary (sal is Latin for salt), a term still in use today that dates back to Roman times when part of a soldier's pay was salt rations. Fearing those around him, the Roman leader Pompey was known to add a grain of salt to his drinks as a supposed antidote to poison. Hence, "taking it with a grain of salt'' is to regard something with suspicion. The earliest known record of salt production was in China about 2000 BC when Emperor Yu decreed that salt had to be supplied to the court as a tribute. Because salt was a commodity that had universal demand, governments often intervened to control salt production and distribution to generate revenue for major national projects. State-run salt monopolies were common in history, such as in Rome about 506 BC. Revenue was also derived from taxes levied on salt sales. The word gabelle refers to the direct salt tax used in France. This tax was so despised that it was a major cause of the French Revolution. Although the tax was repealed in 1790, it was reinstated in 1805 to raise revenue for war. France continued to used the gabelle until 1945. Salt making was an important economic activity in many areas of the world. Archaeological evidence indicates that salt was quarried from hills near the Dead Sea before the Bronze Age. At Hallstatt in the eastern Alps of Austria, rock salt was mined as early as 1400 BC. Solar salt was being produced in the northern Yucatan peninsula by the Mayan civilization from about 50 BC to AD 300. Other than the prehistoric use of salt in the southwestern part of the United States by the Native Americans, the first production of salt by American colonists began in June 1614 on Smith's Island, VA, seven years after the founding of the Jamestown colony. The short-lived activity was in response to the high price of salt being charged by ship's captains who brought salt over as ballast from England. Although Nathaniel Loomis is credited with starting the first commercial inland salt production in the United States at Onondaga Lake in New York in 1790, salt had been made by individuals for private use years earlier. Indians had long known of the salt springs in the Kanawha Valley of Virginia (now known as West Virginia). In 1755, Mary Ingles, a white settler, was kidnapped by Indians and was forced to make salt from the saline springs. After her escape, she told other settlers how to make salt. At Saltville, VA, Arthur Campbell began making salt in 1782 by boiling brine obtained from salt springs. In 1799, William King sank a shaft about 3 m in diameter down about 61 m to the underlying Saltville salt deposits. The shaft flooded before he could extract any rock salt; however, King has the distinction of digging the shaft of the first salt mine in the United States. Fig. 1 shows the King site as it appears today in Saltville, VA. Production of brine from the shaft continued until 1892. Settlers moved into the Kanawha Valley in 1785, but it wasn't until 1806 that Elisha Brooks established the first commercial salt works in Kanawha.

Jan 1, 1994

By E. Viet Howard

During the recent expansion of precipitate copper production at the Chino Mines Division of Kennecott Copper Corporation, Santa Rita, New Mexico, local studies of the dump leaching process were intensified. As these studies progressed it became apparent that a reliable method for locating leach solutions within the dump was required, since the contact between leach solutions and the copper-bearing material would determine, in great part, the recovery of values. In the past, the problem of determining leach solution contact has been attacked by various methods, including destructive testing (dump dissection), indirect observation (such as chloride or dye tracers), and mathematical or laboratory model studies. These methods have not proved completely satisfactory for the studies now being developed. Investigation of methods for in situ observation of leach solutions led to consideration of radiation logging in drill holes, which are petro¬leum exploration and development techniques for locating fluids and measuring porosity in the subsurface. Standard oil field logging equipment was leased, modified, and tested. After successful testing, the equipment was purchased for additional studies. Applications and results of the methods are described in this paper.

Jan 1, 1968

By Howard J. Brown

The Lucerne Valley limestone mining district is in the San Bernardino Mountains, one of the major ranges in the Transverse Range Province of southern California. Several large limestone mining operations are present along the north range front in Lucerne Valley, and the area is one of the premier limestone mining districts in the country. Resources are contained in Paleozoic carbonate rocks that are part of a thick late Precambrian and Paleozoic sequence that uncomformably overlies crystalline basement. The district has been affected by multiple episodes of metamorphism and deformation, as well as by a complex sequence of late Cenozoic structural events. Detailed studies, however, have demonstrated that these rocks can be divided into formations correlatable with late Precambrian to Permian strata of the Cordilleran miogeocline. The district is the leading producer of white, high-purity calcium-carbonate products in western North America. Pluess-Staufer (California) Inc. mines and processes high-purity white limestone from extensive deposits, and is one of the largest producers of high-quality limestone fillers and extenders in the western United States. Major factors influencing the genesis of economic carbonate deposits in the district include depositional environment, post-depositional processes such as diagenesis, dolomitization and/or silicification, regional and/or contact metamorphism and associated intrusive activity, faulting, folding, uplift and erosion, and preservation from erosion. Regional geologic studies, detailed geologic mapping, intimate knowledge of stratigraphy, and recognition of complex structural relationships have proven to be invaluable tools in the discovery of high quality calcium carbonate deposits in the district.

Jan 1, 1987

By H. M. Breza

Recovery of phosphate concentrate has received increased attention as the existing mine and plant production capacity limitations of the Texasgulf Inc. Aurora, North Carolina Mine are reached. Improved mining techniques and mineral processing of waste streams offer a potential to increase overall phosphate production without major expansion of the Mining facility. Innovative processes have been or are being identified to maximize pit mining recovery and to minimize losses in waste streams, resulting in more effective use of the valuable phosphate natural resource. This paper will describe the various continuous recovery improvement programs being implemented to achieve this goal.

Jan 1, 1994

By T. Klemetti, W. H. Su, M. A. Van Dyke

Entry stability in coal mines is dependent on geologic conditions and engineering controls. Most engineering controls in ground control are predictable and standardized for typical geologic conditions. However, geologic anomalies may exist that are difficult to detect with traditional core hole drilling. Borescopes offer a cost-efficient way to gather more geologic data between core holes. Additional data obtained from borescope results provide a clearer picture to enhance detection of hazardous conditions due to geologic anomalies. The equipment, methods, and analysis of borescope results provide geomechanical engineers with a clear understanding of strata behavior and the best information to implement roof control plans and supplemental support to enhance miner safety and health. INTRODUCTION Borescope technology has changed very little since its inception. However, the idea to use borescopes to examine roof strata started with the U.S. Bureau of Mines in 1979 with the production of a fiber-optic borescope (FitzSimmons, et al., 1979). The first documented use of a borescope in the coal mining industry began during the 1980s in Australia by researcher John Shepherd. Shepherd’s idea was to use a borescope to collect a series of data points from the roof lithology and compose a geologic cross section. The cross section was then used to identify key features that suggested the beginnings of roof failure. The features Shepherd identified were bedding plane separations in the roof and low angle, extension, and tensile failures. Shepherd also suggested that the borescope findings could be used for geologic mapping for lithological variation, fracture distribution, and determining if supplemental roof support was needed (Shepherd, et al., 1986). In the United States the first publication about borescope usage for coal mine stability assessment was by Su and associates in 1999, who specifically related the combination of using borescope, geophysical, and corehole data to produce geologic hazard maps (Su et al., 1999). This work directly linked the usage of a borescope with the design of supplemental roof support. The use of borescopes in mining was adopted industry wide by the 2000s. Operator case studies were being published using borescopes to aid in supplemental support recommendations and hazard mapping. An Australian study published in 2007 based the optimization of secondary support after each longwall pass on the results of borescope data. The study stated that the borescope was an invaluable tool for understanding roof behavior (Black, et al., 2007). In 2009, a publication by the National Institute for Occupational Safety and Health (NIOSH) took the concept of borescoping one step further. The work centered around creating a roof quality index (RQI) for limestone mines based on borescope data. The RQI attempted to assign a ranking to establish the nature of the roof and its stability (Ellenberger 2009). In theory, this would have been a very useful tool, but the RQI system has not been widely adopted in the industry.

Jan 1, 2019

By W. H. Schiffbauer

The U. S. Bureau of Mines has been investigating methods and technology that, when applied to existing continuous coal mining machines, may improve production and safety. Toward those goals, a microcomputer network has been designed that provides automated control and monitoring of all mining machine systems using a single twisted pair cable (two conductor stranded wire twisted together to provide a level of noise rejection). The network also provides -connections for intelligent sensors and systems for navigation and diagnostics. The flexibility of the network is demonstrated in that features can be added and removed without redesigning the whole system. A general description of the network's integration to a Joy' 16CM, Joy 14CM, Jeffrey 102, and a custom built auger machine is provided. The microcomputer networks for the Joy 16CM and the Jeffrey 102 have been installed onboard the mining machines and have been extensively tested at the Bureau of Mines test facility. The Jeffrey 102 system has also been tested in an actual highwall coal seam. Both systems have performed satisfactorily. The microcomputer networks for the Joy 14CM and the Auger Miner have been tested and await installation on the respective machines.

Jan 1, 1990