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By Rod L. Norfleet

Cemented tungsten carbides are a sintered powder - metallurgical product essential to modern industry. Because of their moderate unit price and our dependence upon foreign sources for the component raw materials, a growing recycling industry has developed in the United States. There are two basic approaches taken to recycling cemented carbides; those which leave constituting materials unaltered or direct-reuse and those which separate the constitutes back to the raw components. To separate the carbides back to their raw components usually requires expensive chemical processing and is thus confined to the lower value materials such as grinding sludges. The direct-reuse methods recycle cemented carbides back to an intermediate level, a powder capable of being recompacted and resintered into a functional end-product. The three most commonly used methods of direct-reuse recycling, the coldstream process, bloaching and the Bernard or zinc process, are reviewed,

Jan 1, 1984

By William Hodder, Ehsan Alavi, Nader Ghasempour, Daniel Cressman

The Don River & Central Waterfront Coxwell Sanitary Bypass Tunnel (CBT) Project in Toronto will extend approximately 10.5 km from Ashbridges Bay Treatment Plant west under Lake Shore Boulevard, north under Bayview Avenue and east through the Don River park area to the Coxwell Ravine Park. The tunnel is currently being mined by using a shielded dual-mode tunnel boring machine (open and close) capable of operating in EPB mode and lined by using a precast concrete segmental tunnel linear with an internal diameter of 6,300 mm and external diameter of 6,900 mm. The CBT is expected to be excavated mainly through shale bedrock of the Georgian Bay Formation, at approximately 50 meters deep. The tunnel crosses a buried bedrock valley in two locations, in the southern portion of the alignment, adjacent to the Don River, and at the northern portion of the alignment approaching the CX-1 shaft. In these two locations, the bedrock cover is expected to be less than 6 meters. The risk of encountering weathered bedrock, significant ground water inflows or surficial soil deposits through these buried valleys was identified during the design phase. The contract required the TBM to be designed with the ability to probe drill ahead of the TBM and convert to EPB mode if necessary, to cross this area. This paper will discuss the additional exploration that was performed by the contractor to identify the extent of this buried valley, the plan going into the zone of potential weathered shale, and the actual conditions encountered.

Jun 13, 2021

By Cesar Carrasco, Heath Arvidson, Mark Forster

Block models built to represent the geology and rock characteristics of mineral deposits represent huge complex data sets, which form the basis of strategic and business planning, and public reporting of Mineral Resources and Mineral Reserves. Recent advances in cloud computing and database technology developed for the Internet of Things offer a different way of working with these critical data sets. Enabling a cloud based, open data structure with high performance data analytics capability presents a compelling improvement in governance and a democratization of ore body knowledge that can lead to automation use cases that support the digitalization of mining.

Jun 25, 2023

By William A. Cline

The iron mine and beneficiation facilities of Marcona Mining Company are located on the coast of south central Peru. The facilities include an open pit mine, crushing, concentrator containing grinding, magnetic-separation and flotation facilities, pelletizing plants and a completely self sufficient infrastructure. Total production capability is about 10,000,000 DLTPY, of which almost 6,000,000 DLT result from the fine-grind magnetic concentrate. Over 1,500,000 DLT of fine-grind concentrate is obtained from processing high-pyrrhotite ore. Although the orebody contains quantities of oxidized primary ore and transitional ores (mixed magnetite and hematite), the principal ore is predominantly a coarsely crystalline to fine grained massive magnetite.(l-3) In the primary ore the major impurities found are silicates and the iron sulfides- pyrite and pyrrhotite. Sulfur levels typically average about three percent although levels of five percent are not unusual and some ores contain up to ten percent total sulfides. In general the silicates and pyrite are readily rejected from finely ground primary ore by magnetic separation and very basic froth flotation processes. The high iron, low sulfur concentrate produced is particularly suitable for production of high quality oxide pellets. However, pyrrhotite is not removed from the magnetite matrix by either of' these simple beneficiation methods.

Jan 1, 1974

By J. Kuti

In room and pillar mining a large number of working points are arranged to follow a mining pattern. Geological and roof control problems can be overcome or their effect minimized by varying this pattern. Longwall mining on the other hand, fixes the mining pattern for anyone panel. This aspect of longwall mining leads to constancy, so that a well-conceived organization, ventilation, dust and roof control systems lead to daily repetition and subsequent simplicity of control. All the same, a fixed mining pattern calls for a very careful consideration and selection of design parameters. (Ref. 1.)

Jan 1, 1971

By B. G. White

Traditional interpretations of vein ore deposits in the Coeur d' Alene Mining District, such as the view that these deposits formed in a transcurrent tectonic regime during the Precambrian, are being supplanted by the view that the deposits (1) formed in low-grade metamorphic shear zones similar to those that host an important type of gold deposit, (2) display features, such as wall rock carbonate zoning and vein zoning, that are common to ore deposits elsewhere, and (3) are probably Mesozoic and possibly related to emplacement of the Idaho batholith. In recent years, new interpretations have led to major ore discoveries that are likely to extend the life of the district for decades.

Jan 1, 1998

By M. D. Bishop

Early solvent extraction circuits in the uranium industry utilized bona fide kerosenes as diluents for extractant chemicals. These kerosenes were used successfully in the uranium industry; however, at least one plant was destroyed by fire resulting from the use of a low flash point kerosene. Although the term "kerosene" is used throughout the solvent extraction industry, the authors have been unable to find any use of kerosene in copper solvent extraction circuits. A term that is occasionally used with reference to diluents is "metallurgical kerosene." Such a term is unrecognizable in the petroleum industry. Kerosene [or kerosine] is a flammable hydrocarbon mixture that is less volatile than gasoline. It is produced for combustion purposes and may have variable compositions of organic compounds including alkanes, alkenes, alkines, and aromatics. Diluents are constant composition hydrocarbon mixtures developed specifically for use in solvent extraction processes. These products usually have much lower vapor pressures and higher flash points than kerosene. In solvent extraction systems, they typically comprise 70 to 95 v/o percent of the circuit organic. The primary purpose of the diluent is to adjust the extractant concentration to the working range of the operation. The diluent and extractant must be completely soluble or miscible with each other. Secondary diluent effects are to promote transfer kinetics, optimize phase disengagement, and minimize both organic in aqueous and aqueous in organic entrainment.

Jan 1, 1996

By Jr. Smith

Borates have been mined in the desert areas of California and Nevada for more than 100 years. To about 1890, playa surface mining provided the chief sources of boron minerals. Underground mining of colemanite and later of borax and kernite was predominate until about twenty years ago. Open pit mining of the large deposits of borax and kernite near Boron, California has been most significant for the past twenty years. Mining of colemanite in the Ryan, California area, near Death Valley, began in 1907. Following the discovery of the large deposits in the Boron area (about 1957), mining in the Death Valley area became nearly nonexistent. Only small tonnages were mined for special uses. Little mining was done in the Boraxo area near Ryan. The first claim was made in about 1915 In 1960 the area became the property of the Kern County Land Company, which was acquired by Tenneco Oil Company in 1967. In 1976 the various borate properties and claims in this region were acquired by American Borate Corporation. The open pit mine is now approximately 400 feet (121.9 m) deep, 3000 feet (914.4 m) long and 1000 feet (304.8 m) wide. The borates in the Boraxo pit consist primarily of three minerals. These are about 50% coiemanite (C2B6O11' 5H2O), about 40% probertite (NaCaB5O9.5H2O), and 10% ulexite (NaCaBcO9.8H2O). The colemanite, along with boric acid and high-grade coiemanite ore from Turkey provide the only sodium-free borates for production of textile grade fiberglas. When heated to its decomposition temperature, colemanite decrepitates to a fine powder. This provides the basis for the concentration process. The gangue minerals in this deposit are primarily calcite and clays, including bentonite. The ore body has a very low arsenic content.which is a desirable feature. Test work had been done with samples prior to the results discussed herein. This paper will discuss results of test work which were the basis for erection of a plant, and the subsequent plant operations.

Jan 1, 1978

By L. J. Blatnica

Throughout the 1980's the tem Mine-Wide Monitoring System has had various meanings for manufacturers of these systems and underground mine operators alike. System suppliers had visions of grandeur in the early 80's as they envisioned each mine, that has more than a single section, installing a computer based monitoring system to provide surveillance, control and documentation of the entire mining operation, including everything from a single heat detector to the weekly payroll. In a few cases this may have become reality but the truth is these systems have quietly become a steady but unspectacular workbase for the modern mining industry of the 1990's. As it exists today the total market for underground monitoring systems may not exceed $10 million annually. Suppliers have lowered their expectations of the dollar value of this particular market. Some were entering a new market because of experience with computer based data acquisition systems. Others had been active in the mining industry for years with more traditional equipment (communication systems, methane monitors, safety equipment, etc.) and decided to become involved with Mine-Wide Monitoring Systems.

Jan 1, 1990

By T. P. Meloy

A methodology is presented for finding feasible or locally optimal designs in the class of homogeneous, countercurrent, processing networks performing two-component non-sharp separations. The advantage of the methodology developed here is that given a set of independent performance criteria (specifications such as network separation factor, beneficiation ratio or recovery), a feasible or locally optimal countercurrent network design meeting those criteria can be found in one step. In the methodology, graph-theory was used to explicitly obtain the exact network responses of specific countercurrent networks. These responses were used to formulate the linear recursion equations whose solution gives the expressions for the countercurrent network responses which are a function of the stage transfer functions for two-component, non-sharp separations. These expressions are also functions of the network variables n and c. These expressions, together with the set of independent design criteria, were solved simultaneously for n and c using the Levenberg-Marquardt algorithm for systems of constrained, non-linear equations. The network variables n and c embody the coded network design information which is used to find the feasible network design which satisfies the set of independent performance criteria.

Jan 1, 1994

By W. R. Reed

This study evaluates the roof-bolter canopy air curtain (CAC) system in an exhausting face ventilation system, demonstrating its effectiveness and illustrating the CAC protection zones. Two scenarios are considered: (1) a roof-bolting machine in the center of the entry for installation of the fifth row of bolts from the face, and (2) a roof-bolting machine positioned close to the face for the installation of the last row of bolts. In both scenarios, the bolting machine is placed in an environment that contains 6.0 mg/m3 of respirable dust and is ventilated by an exhaust curtain with 9,000 cfm (4.25 m3/s) of air to simulate the roof-bolter machine operating downstream of a continuous mining machine. Two operation positions are simulated at the same bolting location: dual drill heads in the inward position for two inside bolts and in the outward position for two outside bolts. The influence of the CAC on airflows and dust dispersion is evaluated with the CAC operating at 250 cfm (0.12 m3/s) with dust reductions ranging from 39.5 to 82.8 percent. When the roof bolter is operated close to the face, increasing CAC airflow was required for adequate protection, as the dust reductions can be as low as 39.5 percent. Increasing CAC airflows to 350 cfm (0.17 m3/s) and 450 cfm (0.21 m3/s) were evaluated, demonstrating that dust reductions increased to 59.7 percent (350 cfm) and 72.0 percent (450 cfm). These results revealed improvement in respirable dust reductions compared to the CAC airflows at 250 cfm when the bolter is operated close to the face, showing the CAC can provide protection against high respirable dust concentrations for roof-bolter operators.

By E. M. Frizzell

Development of mobile crusher systems for surface mining, allowing extension of continuous conveyor haulage systems into the pit, is traced from its introduction to the present. Variations in configurations are reviewed, and the compelling reasons for using mobile crusher systems are explored.

Jan 1, 1983

By J. J. Scott

As a Rock Mechanics investigator, the author has, Over his career, attempted to use his best knowledge in developing better rock control fixtures. Based on the experience of nine years of development of friction rock stabilizers, in 1980 he decided to launch a new investigation to develop a unique roof support fixture which would fit the coal mining market. The largest single user of roof bolts in the world is the American coal mining industry, historically using up to 100 million fixtures per year. In 1989 they used approximately 82 million fixtures.

Jan 1, 1990

By Robert R. Munro

Traditional aggregate sources, that is the riverbeds, the alluvial fans, located relatively close to the developing urban centers are being foreclosed to mining. As the sand and gravel reserves are depleted, those production plants are unable to secure additional adjacent reserves and are being forced to close down. The sand and gravel industry, in many respects, is its own worst enemy. We promote development, we promote the paving of streets, the building of houses, and industrial and commercial centers, and because of economics, we tend to favor those developments located close to our operations. Thus, we encourage development by our neighbors who soon become our detractors. In general, urban development is not compatible with sand and gravel mining. The neighbors don't like the view of the pits or the quarries, they complain about the "dust", about noise, about trucking . . . in general, the neighbors are not happy being close to an aggregate source.

Jan 1, 1984

By Y. C. Kim

This paper describes the implementation aspect of a blast hole kriging system which has been developed for the purpose of daily ore-waste control in an open pit mine. The primary goal of blast hole kriging is to improve the ore-waste delineation procedure. A complete computer program package called Blast Hole Kriging (BHK) System was developed for IBM/PC AT or XT computer, using Fortran language and supplemented by a few Assembly language routines for bit-map manipulation. The emphasis of this paper is on the implementation aspect of the developed system. For this reason, the requirements for practical implementation and the system design considerations are discussed in the paper, as well as the main features of the University of Arizona's BHK System.

Jan 1, 1990

By G. H. Roybal

Humic-acid-rich deposits exist in Arkansas, Florida, Louisiana, New York, North Dakota, Michigan, Minnesota, Texas, and Wyoming (Burdick, 1965) and in New Mexico (Shomaker and Hiss, 1974). New Mexico humic deposits are associated with coal in the northwestern part of the state where humate and weathered coal are presently mined. Discussion of the humic -acid industry in New Mexico requires an understanding of complex terminology and coal geology. TERMINOLOGY Humic material is not a pure substance so an ambiguous and complex terminology is in use by geologists, chemists, soil scientists, agronomists, and producers. Material mined for its humic-acid content is an extremely variable mixture of base-soluble humic, fulvic, and ulvic acids and their salts, formed during partial or complete decay of organic matter. This decay releases a high-molecular-weight organic material which is darkly colored, partly colloidal, and weakly acidic.

Jan 1, 1985

By BHAMIDIPATI S. SASTRY, Pavan Kumar Kattamuri, ADITYA PANDEY

The thermal conductivity of rock surrounding the airway is one of the most important thermal properties for estimating strata heat transfer into the mine air and for designing the air-cooling strategies. Several laboratory methods are available for the determination of thermal conductivity; however, most of them are complex and cumbersome. The present study explains the working principle of Lee’s apparatus which is relatively simple, easy to fabricate and use, and provides consistent results. In the present study, thermal conductivities of sandstone cores obtained from an Indian coal mine are determined using Lee’s apparatus. An approach is discussed for determining the temperature gradient of sandstone specimens while cooling and used for calculating thermal conductivity. The thermal conductivity of different sandstone specimens attains values between 2.37 and 2.59 W m− 1 °C−1. For different sandstone cores obtained from the field, properties including specific gravity, specific heat capacity, thermal diffusivity, and porosity, along with thermal conductivity, are determined and highlighted in this study.

Jul 20, 2021

By I. E. Odom

The physiocemical properties and industrial uses of the clay mineral montmorillonite are reviewed. Montmorillonite is the most abundant species of the smectite clay mineral group and is the predominant mineral composing bentonite deposits. The crystal structure, chemical composition, exchangeable ion type, and small crystal size are responsible for several unique properties, including a large chemically active surface area, a high cation exchange capacity and interlamellar surfaces having unsual hydration characteristics. The type of exchangeable ion Na, Ca and/or Mg has a major influence on industrial and chemical uses of montmorillonite because of their hydration characteristcs. Natural occurrences of Na montmorillonite in commercial quantities are geographically limited, but Ca-Mg montmorillonite deposits are known world wide. Foundry, well drilling, pelletizing and civil engineering constitute the major uses of montmorillonite, but the total array of uses of montmorillonite exceeds that of any other mineral.

Jan 1, 1986

By Taner Aydogmus

The A$29 billion Chevron-operated Wheatstone Project is one of Australia’s largest resource projects. Located at Ashburton North, 12 kilometers west of Onslow in Western Australia, the project will consist of two Liquefied Natural Gas (LNG) trains with a combined capacity of 8.9 million tons per annum and a domestic gas plant. The LNG Plant will serve the offshore gas fields, which are situated some 250 km off the coast of Onslow in Western Australia. Once operational and on-stream, the Wheatstone Project will contribute to Australia becoming the world’s second largest exporter of LNG. For crossing the environmentally sensitive shore area, a micro-tunnel with an internal diameter of 2 m and approx. 1,242 m in length has been constructed by means of the pipe-jacking method. The micro-tunnel will accommodate a 1.1 m diameter pipeline (trunkline) to deliver gas from the offshore fields LNG Plant. The Wheatstone shore crossing design involves a number of unique challenges owing to its coastal location, where the alignment crosses through a shore area and terminates in a marine environment. This paper provides an overview of the Wheatstone Shore Crossing Project, presents the key features, and discusses the main aspects of the micro-tunneling design.

Jun 13, 2021

By E. Milosavljevic, C. H. Bucknam, K. L. Gabby, T. C. Eisele

"Since mercury is chemically similar to silver, it tends to dissolve along with the silver and gold during cyanide leaching. Ultimately, mercury is recovered along with the silver as mercury/silver/gold amalgam, which requires retorting to remove the mercury prior to refining the silver and gold. A possible approach to separating mercury from silver and gold in cyanide leach solutions is to take advantage of the replacement reaction between [Hg(CN)4]2- and Ag2S, which results in precipitation of mercury as HgS while dissolving silver as [Ag(CN)2]-. Results are presented demonstrating that mercury can be removed from cyanide solutions with high effectiveness while, at the same time, recovering additional silver in solution. Initial experiments with static flasks in the laboratory showed a high degree of mercury removal could be achieved. Results using actual metallurgical plant products in bottle roll tests indicate the process works on a larger scale, but also results in significant gold losses if the solution being treated has high gold levels, such as carbon stripping pregnant eluent solution. IntroductionThe dissolution of mercury along with precious metals during cyanide leaching is a long-standing problem, which can result in significant mercury toxicity issues (Washburn, 2003). Mercury is first dissolved by the cyanide solution, and then, since it has a great deal of chemical similarity to silver, it follows silver throughout the concentration and recovery processes, ultimately being recovered as a silver/ mercury amalgam when the metal is precipitated by either the Merrill-Crowe process or by electrowinning.While it would be desirable to either prevent mercury dissolution entirely while still allowing silver dissolution, or to selectively capture mercury before the precious-metals recovery step, there is not yet an effective and economically practical approach to doing this (Grosse, 2003; Ravichandran, 2004; Misra, 1998; Pai, 2000). There are a few processes that have been proposed, such as differential adsorption. While activated carbon, as used in the carbon-in-pulp process, is not highly selective between mercury and silver (Washburn, 2003), it may be possible to achieve some separation by selective elution of the carbon to produce high-mercury and low-mercury eluates (Bunney et al., 2010). Certain synthetic resins were shown to be selective for gold but are more expensive than carbon, requiring special equipment, and have not yet been shown to be selective for mercury (Grosse, 2003). There may be potential for differential dissolution approaches, as thiosulfate leaching does not dissolve mercury sulfides as readily as it dissolves gold (Oraby et al., 2010), and it is possible that it may be similarly more selective for dissolving silver relative to mercury. Some work has also been done with selective precipitants, such as sodium polythiocarbonates (Bucknam, 2007), and 1,3-benzenediamidoethanethiol (Matlock, 2002). Common problems with these approaches include introduction of a solid:liquid separation step, reagent costs, the need to measure the mercury concentration for process control for minimizing silver losses, and regulatory requirements to retort otherwise stable mercury concentrates."

Jan 1, 2015