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By Rees D. Groves

Cement copper is ordinarily converted to marketable metal by processing in a conventional smelter and refinery. Because of rapidly increasing cement copper production and limited excess smelting capacity, other techniques were investigated for preparing marketable copper products. One route was to make copper powder for industrial use. The process scheme employed flotation for rejecting the bulk of the impurities, acid leaching to remove residual iron and aluminum, reduction sintering to eliminate oxygen, and grinding to obtain powder. Another route was to sinter the floated and leached copper into the form of anodes and electrolyze these to yield refined copper cathodes. At a current density of 30 amperes per square foot, power consumption for electrorefining was 185 kwhr per ton of copper. The feasibility of preparing commercial-size anodes by sintering is still to be assessed.

Jan 1, 1970

By Hamid Maleki

This paper reviews a study conducted for Australian Coal Research Limited (ACARP) to assist Anglo-American operations with better understanding of coal burst mechanics and control based on U.S. practical experience, investigations, and inspections in three major U.S. coalfields over the past 45 years. The study examined both nonviolent and burst-prone case studies to identify contributing risk factors and addressed failure mechanisms for major U.S. coalfields in Utah, Colorado, and Kentucky, which have diverse characteristics. To investigate the mechanics of coal burst, a multipronged approach is used. First, field measurements in three mines from East Mountain, Utah, are complemented with finite-difference stress analyses to address the importance of horizontal stress in coal pillar mechanics of violent failure. Second, the computational procedures for estimating seismicity resulting from slip along geological discontinuities are reviewed, as these measurements point to seismicity being the trigger mechanism for violent failure of marginally stable structures. This joint-slip seismicity mechanism is in agreement with the more recentimproved re-examination of mining-induced seismicity (MIS) data from the Crandall Canyon Mine, Utah by University of Utah (UOU). Third, a hybrid statistical-analytical methodology is applied for identifying significant factors affecting coal burst. It utilizes data from 30 case studies including those from Utah, Colorado, Kentucky, and other eastern U.S. mines. The statistical approach reinforces field measurements and points to strata rigidity, joint spacings, and horizontal stress field as significant factors affecting damage resulting from coal bursts. This provides practical capabilities for identifying operations of higher risk using a rigidity-cavability variable. Overall, the study provides valuable insights into the mechanics and risk factors associated with coal bursts in major U.S. coalfields. By utilizing a multipronged approach that incorporates both field measurements and statistical-analytical calculations, the study offers practical capabilities for identifying operations of higher risk and improving coal burst control.

Jul 1, 2023

By Howard L. Hartman

The federal government's declining role in funding research has created a critical dollar gap for university departments of mining engineering. Industry is not unaffected by the drought: not only is research lagging, but hard- pressed universities are going to the private sector for funding. This paper's thesis is not that mining companies should shower universities with philanthropy, but that a quid pro quo ought to be exacted: a research partnership should be contracted on a pay-as-you-go basis. A model exists at The University of Alabama (albeit not in mining) that may lend itself to adoption by our industry.

Jan 1, 1984

By Hou Xilun

Three production methods of rapid cold bonding and low temperature bonding pellets using sponge iron powder as a binder have been successfully developed. These methods differ from ordinary bonding method by no addition of salt and other catalyzers, no corrosion of equipment and no pollution of environment. Mechanism of pellet bonding is studied. Experiment shows that these pellets have good metallurgical properties. A semi-industrial test has proven the laboratory results, with the production of metallic pellets continuous and stable. These methods are substituted for traditional high temperature firing of oxidized pellets in direct reduction. As a result, the plant for oxidized pellets can be saved and substituted for grate in the grate-kiln system. Thus, 20% of the investment could be saved. Production cost may also be decreased. The production of cold bonding pellets does not need additional area.

Jan 1, 1980

By J. A. Matar

Mineralization features at the Bajo La Alumbrera porphyry copper-gold deposit are discussed as they affect gold leaching and copper flotation behavior. Alteration-mineralization geological blocks are assigned in the zoned body, and each required its own geostatistical model. They extend horizontally outward from potassic to the phyllic-propylitic boundary, vertically from surface down to 300 meters, and include oxide, secondary enriched, and hypogene mineralization. Copper and gold values are calculated geostatistically from assays and all available geologic-mineralogic information. Reserves are classified for each geologic block and for each open-pit bench into leach or float ore according to metal grades, geologic characteristics, and supergene-hypogene relations. Finally ore extraction behaviour is briefly described, grouping gold and copper reserves into metallurgical families.

Jan 1, 1986

Because the Environmental Protection Agency has identified methane as a greenhouse gas, the importance of de gasification through gob wells has become more critical. It has been observed that the degree of methane emission is closely related to the geomechanical characteristics of coal bearing strata, roof, floor, and surrounding coal seams. Monthly production data from 250 gob wells were collected from the Warrior Basin in Alabama, and many interesting correlations were observed between methane production with longwall face width, face advancement rate, number of gob wells in a panel, and geologic columns. Extensive finite element analyses were performed to estimate the characteristics of the emission zone in an attempt to corroborate these findings. This paper describes an investigation for developing correlations between the geomechanical behavior of the methane emission zone with methane production.

Jan 1, 1996

By M. Akser

Ilmenite, rutile, and zircon deposits of commercial importance have not been reported to-date from Turkey. However, information from recent reconnaissance activities indicates the possibility of an economically viable heavy-mineral deposit along the Black Sea coast of Turkey in the vicinity of Ormanli, northwest of Istanbul. Consequently beach and sand dune samples were collected from that area for additional analysis. Laboratory methodologies, designed to simulate standard industrial heavy-mineral plant practices, were used to analyze and evaluate the samples. Based on the analyses, and current market needs, none of the deposits in the Ormanli area qualify as a commercial heavy-mineral deposit.

Jan 1, 1995

By K. N. Han, H. C. Cho, R. Kim

"A comprehensive analysis of the effect of OH- on various cations in hydrometallurgical systems has been investigated. Cations chosen for this analysis included groups 1A and 2A, rare-earth elements and other common transition metal ions such as Cu2+, Fe2+, Fe3+, Mn2+, Ni2+, Co2+, Ag+, Cd2+, U4+, UO2 2+, Hg2+, Al3+ and Zn2+. The Newton-Raphson technique was used to calculate and plot various metal species over a wide range of pH. This study has clearly shown that by adjusting the concentration of OH-, the separation of Fe from Mn, U from V, Ce and Eu from other rare-earth elements, and In from Sn is possible. The effects of hydrated metal ions on the separation and removal of various metals from each other under various conditions is discussed.IntroductionThe primary purpose of hydrometallurgical processing is to extract, remove and purify various metals from diverse sources. Hydrometallurgists are frequently preoccupied by the extraction of cations in metallic form, but overlook the important role anions play in such processes. A proper choice of anions can determine the fate of successful extraction, removal and purification of metals (Esmaeili et al., 2005; Brbooti et al., 2011; Wei et al., 2005; Jeppesen et al., 2005; Al-Tarazi et al., 2004), and also separation (Farha et al., 2011; Sevenich and Fritz, 1983; Rashid, 1974) of cations from various solutions.In this study, the authors have examined some of the effects that anions play in various solutions. The anion considered in this study was the first hydroxide, OH-. Other anions, such as Cl-, Br-, I-, and CN-, will be dealt with in the second part of the series of two papers."

Jan 1, 2015

By K. J. Bruxvoort

Background ground water quality is often used to drive remediation programs at sites with waters affected by mining activities. In the past these levels were sometimes chosen without rigorous statistical and geochemical analysis. A probability distribution approach was used at the Sweetwater Uranium Project to separate a large set of geochemical data into populations that represent contributions from different sources. Natural background populations were identified for major ions, metals, and radionuclides, and were submitted to the Nuclear Regulatory Commission to modify the extent of a Corrective Action Program and to establish control limits for future monitoring.

Jan 1, 1998

By J. Andrew McGlenn, Brian McInnes, Bruce Downing, Murray Gant

The Second Narrows Water Supply Tunnel crossing beneath Burrard Inlet is an important component of the Greater Vancouver Water District’s plans to increase seismic resilience and meet increasing water demands. The project included the 110-meterdeep (350 ft) South TBM Receival Shaft, one of the deepest shafts to date in the sedimentary rock unit underlying much of Metro Vancouver. The shaft encountered varied sedimentary rock types, including fractured rock, with accompanying high groundwater inflows. This paper discusses the design and construction challenges associated with this shaft and the necessary means to complete the shaft in time for TBM arrival.

Jun 13, 2023

By P. K. Sims

One-day field trip via U.S. Highway 6 and Colorado Highways 119 and 279 from Golden, Colorado to Idaho Springs. This field trip provides an opportunity to observe aspects of the Laramide ore deposits in the Central City and Idaho Springs mining districts and the Proterozoic basement rocks, which host the ore deposits.

Jan 1, 1986

By T. B. Linde

The Morenci In-pit Crusher and Conveyor System has been designed with safe production and cost savings in mind. Large open pit mines around the world have been installing semi-mobile crushers and linking them with a pit conveyor system to lower unit cost. At Morenci two 60/89 in. gyratory crushers are incorporated into the semi-mobile crushing plants. The ore is reduced to -8 in. and transported out of the mine on a 60 in. steel cable belt. This paper includes an overview of the Morenci In-pit Crusher and Conveyor System from the drawing board to open pit installation and finally a discussion on operating and repair considerations.

Jan 1, 1990

By Yuting Xue, Khaled Mohamed

Rib control is a critical component of underground coal mining operations, and comprehensive rib support design is essential for ensuring the safety of miners. However, there is currently no standardized approach for rib support design in the United States. To tackle this issue, the National Institute for Occupational Safety and Health (NIOSH) has developed a standalone application, Design of Rib Support (DORS), for rib stability assessment and rib support design under development load. The rib support design in DORS starts with the rib support density, which is determined from the unsupported rib factor of safety (RibFOS). The relationship between rib support density and unsupported RibFOS was obtained from the collected field data. The objective of this research is to validate DORS rib support design by analyzing the extent to which the proposed design capability was utilized to support the coal ribs using numerical simulations. A series of numerical models with varying overburden depth and rib height were built and the ribs were supported with the DORS-recommended rib support design. The bolt load was analyzed under different conditions and the results show that bolt load varies with the overburden depth, the location of the bolt and bolt length. The load in the bolt(s) increases with the reduction in unsupported RibFOS. The bolt(s) start to yield when the unsupported RibFOS falls below a threshold value of 0.8 and secondary support is necessary.

Jun 25, 2024

By Rodger C. Smith

The topic chat has been assigned to me ?Economic and Political Climate of the Potash Industry? is a function of two basic facts: 1. Potassium is absolutely essential to plant and animal growth. Along with nitrogen and phosphorus it is one of three major plant nutrients, the three nutrients required in largest quantities for plant growth. 2. United States is unequivocally an "have not" nation with regard to potassium. Quantity of potassium ores is limited and, more disturbing, the cost of production at all U.S. potash mines is marginal in comparison with the major producing countries, i.e. Canada and U.S.S.R.

Jan 1, 1983

By K. C. Liddell

Chemical processing research made notable advances during 1986. This overview is necessarily brief. It is intended, though, to give the flavor of selected areas where recent activity has been high. At the 1986 Annual Meeting of The Metallurgical Society, a symposium was held on hydrometallurgical reactor design and kinetics. R. G. Bautista, R. J. Wesely, and G. W. Warren edited the resultant proceedings volume. This is the first available volume on this subject. It includes 26 papers on fundamental kinetic studies, modeling of reaction kinetics and reactor performance, and pilot and production-scale operations. Metals discussed include silver, gold, platinum, titanium, cobalt, nickel, zinc, copper, manganese, and iron. Agitated tanks, heaps, dumps, pachucas, pressure auto-claves, electrolytic reactors, liquid membranes, and fluidized beds are among the reactor types covered. An international symposium dealt with iron control in hydrometallurgy. It was sponsored by the Metallurgical Society of CIM, the Institution of Mining and Metallurgy, The Metallurgical Society of AIME, and Gesellschaft Deutscher Metallhutten and Bergleute. J. E. Dutrizac and A. J. Monhemius edited a proceedings volume containing 41 papers. These covered many areas of process chemistry, solvent extraction, precipitation, treatment of pickle liquors, impurities, residues and the environment, and process selection. Precious metals Concerning precious metals processing, the US Bureau of Mines IC 9059 is noteworthy. It includes papers presented at a USBM briefing at the Western Mining Conference in Denver. Topics covered included ion exchange, staged heap-leaching direct-electrowinning, and mercury precipitation during cyanide leaching of gold ores. Also dealt with were carbonaceous gold ores, carbon adsorption and desorption, heap leaching, the carbon-in-pulp process, and precious metals recovery from electronic scrap and solder. R. C. Sandberg and J. L. Huiatt (Journal of Metals, June 1986, and USBM RI 9022) developed a method to recover silver, gold, and lead from a complex sulfide using ferric chloride, thiourea, and brine-leach solutions. Gallium Gallium recovery was also a subject of considerable interest. Much information on this topic is proprietary. But two papers described solvent extraction of gallium. V. P. Judin and R. G. Bautista (Metallurgical Transactions B, 1986) developed an equilibrium model to separate gallium chloride from aluminum chloride. Tributyl phosphate was the extractant studied. T. Sato and H. Oishi (Hydrometallurgy, 16, 1986) investigated gallium extraction from sodium hydroxide by using Kelex 100. Data were given on the equilibrium distribution and the extraction kinetics. Galena Interest continues in recovering lead by hydrometallurgical processing of galena. J. E. Dutrizac; S. H. Kim, H. Henein, and G. W. Warren; and M. C. Fuerstenau et al. (Metallurgical Transactions B, 1986) all investigated leaching of PbS by ferric chloride. Dutrizac reported parabolic kinetics and reaction control by outward diffusion of lead through a porous layer of elemental sulfur. Kim, Henein, and Warren, however, reported that two leaching reactions occur. A nonoxidative reaction produces H2S and there is an oxidative leaching by ferric ion. Acid dissolution was found to predominate when the acid activity to ferric activity ratio is high. Surface chemical reaction was reported to be controlling. Fuerstenau et al. also reported that mass transfer through the sulfur layer is rate determining. But they believe that the species transferred are chloro complexes of ferric ion. In other work on lead, A. Y. Lee, A. M. Wethington, and E. R. Cole, Jr. of the USBM described an environmentally acceptable hydrometallurgical alternative to the smelting of lead concentrates (RI 9055). Uranium In spite of depressed prices, much work has been reported on uranium processing. R. G. L. McCready, D. Wadden, and A. March-bank (Hydrometallurgy 17, 1986) described the nutrient needs for in-place leaching by T. ferrooxidans. They reported the optimal conditions for uranium solubilization. L. E. Eary, H. L. Barnes, and L. M. Cathles (Metallurgical Transactions B, 1986) carried out an experimental and modeling study of uraninite dissolution. They concluded that ferric ion preferentially leaches uraninite in pyritic ores. Hydrogen peroxide was found to be less selective. A. Vuorinen, P. Hiltunen, and O. H. Tuovinen (Hydrometallurgy 15, 1986) studied redox and precipitation reactions of iron and uranium in leach liquors. P. T. Chiang (Hydrometallurgy 17, 1986) reported on the effect of uranium loading in the DEPA-TOPO process to separate uranium and iron from wet-process phosphoric acid. F. J. Hurst (Hydrometallurgy 16, 1986) conducted a fundamental study of the separation of uranium from phosphoric acid by DEPA and TOPO. D. E. Chia and W. C. Cooper (Hydrometallurgy 16, 1986) reported on bench and pilot scale work to recover uranium by the HIMIX process. They reported that the acid consumption to produce an eluate suitable for yellowcake

Jan 5, 1987

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 Sanja Zlatanic, Michael P. Della Posta

New York State’s Metropolitan Transportation Authority (MTA) has undertaken the largest transportation project in New York City. The East Side Access Project (ESA) will introduce MTA’s Long Island Rail Road (LIRR) service to the East Side of Manhattan, to a new terminal located beneath the existing, landmark Grand Central Terminal(GCT). Construction of the Manhattan Segment of the project will affect overlying operating facilities of two other MTA entities, Metro-North Railroad (MNR) and New York City Transit (NYCT) and major Midtown Manhattan buildings. The paper describes the evolution of the GCT concept at Manhattan from a shallow alternative proposed by a Major Investment Study (MIS), that would require extensive underpinning of multi-story buildings and have considerable impact on MNR and NYCT operations, to a deep alternative with lesser risk and potential for disruption.

Jan 1, 2001

By A. W. Khair

In 1985, an extensive longwall mining research project was initiated by the West Virginia University Research Center entitled "An Improved Longwall Mining Technique" with the purpose of providing operational guidelines for the mining industry to enable efficient operation of its existing and projected longwall installations. One task involved in this extensive research project was monitoring ground movements due to longwall mining and evaluating their impact on surface and subsurface structures. This paper presents an analysis of the effects of topography on quasi-static and dynamic ground movements and the severity of damage inflicted on surface structures. The site was chosen for the study with an attempt to obtain a representative account of the topography experienced in the Northern Appalachian region, and more importantly to contain a substantial number of varying topographical features i.e., mountains, hillsides, valleys, and flat bottom land. The study was made possible by typical subsidence monitoring technqiues, however subsidence monuments were surveyed on a frequent basis, intermittently during face advancement. Ground movements were investigated under both quasi-static and dynamic conditions. This provided insight into the propagation of subsidence and the dynamic affects it has upon surface structures.

Jan 1, 1987

By Dale R. Andrus

Why is there such an increased thrust toward positive multiple use land management and where will it lead? History and purpose of the mining law of 1872. John Marshall discovered gold at Sutter?s mill near Coloma, California, on January 19, 1848, and utter chaos resulted. The great migration of people to the undeveloped western lands had begun. Prior to this discovery, copper, lead, and iron had been the minerals for which the laws were made. With this discovery of gold on the public domain, it became apparent that congressional legislation was necessary. This became even more apparent as each of the numerous mining districts which were springing up in California, and elsewhere in the west adopted local miners' customs to regulate their activities. Although these early miners acted under mining district rules and in some cases state regulations, they were, in reality, appropriating minerals without sanction of federal law.

Jan 1, 1970

By Armando Correa de Araujo

Cationic flotation of quartz is currently utilized for the concentration of iron ores and for the cleaning of phosphate concentrates. The present work deals with depression of quartz in the presence of aluminum ions during cationic flotation. It was established-that aluminum ions depress the flotation of quartz with an amine, especially under neutral and very slightly alkaline conditions. Studies of adsorption of Al ions on the quartz surface as a function of pH correlated with depression of this mineral with an amine as collector. The presence of Al ions also enhanced the depressant action of corn starch on quartz The sodium salt of ethylenediaminotetra-acetic(EDTA) was found to be an effective complexing agent to supress the depression caused by aluminum ions.

Jan 1, 1984