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By Terry Owen

Business development process. Throughout Cyprus Amax's early months in Russia, the company stayed focused on what was needed from a deposit for economic success. Cyprus Amax's reason for success in Russia is that all involved - its Russian partners, the workforce and expatriates - provided a focused effort that served the project as it worked through the tender process and the Russian regulations. The company developed an understanding of the regulatory process by working with solid, ethical partners. Infused into the Kubaka management structure were Russians with the knowledge to facilitate the process and a professional group of expatriates. Developing credibility and a solid rapport with the Russian mining authority was critical to the success of this venture. Identifying and gaining the trust of key Russian individuals was also critical during the early stages. Gaining their trust and building credibility was part of the process. These key Russians were brought to the United States to visit existing Cyprus Amax mines. These efforts proved valuable in building an understanding with the Russians about the kind of company Cyprus Amax is and the kind of efficient operations that it can run. This was a learning process for all parties. Fortunately, the company was dealing with intelligent and educated people.

Jan 1, 1997

By M. Westerstrand

It is known that the water chemistry of the process water during ore refinement can affect product quality, such as iron pellet strength. The main objective of this study was to quantify the amounts of major elements, such as Ca, Mg, Na, S and Cl carried by process water and by magnetite grain surfaces to the end product, iron ore pellets made from magnetite ore from the Kiirunavaara Mine in northern Sweden. In addition, the amount of colloids (0.22µm ? 1kD) in the process water was examined by ultrafiltration. The amounts of various elements sorbed to the magnetite surfaces were estimated by leaching with Milli-Q water, MgCl2, NH4-acetate and Na-acetate. Total dissolved solids were between 1,446 and 1,775 mg/l, dominated by Ca, S, Na and Cl (89%). The colloidal fraction was less than 3% for major ions. For Ca and Mg, sorption to magnetite surfaces was a much more important transport mechanism for the pelletizing process than evaporated process water, but for Na, Cl and S process water was an important carrier.

Jan 1, 2010

By SUHAINA ISMAIL, NORLIA BAHARUN, SHAIK ABDUL RAHMAN, WAN NUR SYAFIQAH ANUAR, MOHAMMAD REZAEI ARDANI

Hypochlorite leaching system is a strong oxidizing solution for metal sulfides, which are naturally associated with gold extraction. This study evaluated the hypochlorite leaching of refractory gold ore by using the response surface method–central composite design (RSM-CCD) as a statistical approach in determining the optimum condition of gold extraction from refractory gold ore. The studied parameters for the gold recovery were pH (4 to 6), concentrations of Ca(OCl)2 (0.5 to 1.5 M) and NaCl (2.5 to 3.5 M) in the solution. It was found that the maximum gold extraction of 82.46% (13.85 g/t) was achieved at a pH of 4.0 with NaCl and Ca(OCl)2 concentrations of 2.93 M and 1.08 M, respectively. The statistical analysis also revealed that the amount of gold recovery in chloride solution was significantly depended on pH as the main factor, followed by concentrations of Ca(OCl)2 and NaCl.

Jan 8, 2021

By Lingyun Zou, Xinghai Lei, Tiezheng Li, Yifei Song, Nan Wang, Yang Li

The stability of key strata is of utmost importance in ensuring safe and effective coal seam mining operations. To minimize disturbance impacts on these strata and ensure their stability, it is crucial to assess the degree of disturbance caused by mining activities. This study proposes the evaluation index “disturbance degree of key stratum (KSDD)” and establishes a quantitative KSDD criterion to measure the degree of disturbance on key strata. To facilitate the assessment process, an intelligent calculation system for KSDD is developed. The classification criteria are derived by combining the measured three-zone heights from multiple mines. The reliability and accuracy of the KSDD quantitative criterion are validated using field measurement data. Furthermore, the KSDD quantitative criterion is applied to the Meihuajing mining area No. 23, and the distribution characteristics of KSDD are analyzed. The findings of this study can serve as a valuable reference for reducing disturbance and enhancing the stability of key strata during subsequent mining operations. Overall, this work contributes to the field of ground control in coal seam mining by providing a comprehensive approach to assess and mitigate the disturbance caused by mining activities on key strata.

Mar 8, 2024

By D. Berberick

Hecla?s Lucky Friday Mine is a deep, underground producer of silver, lead and zinc in the Coeur d?Alene mining district of northern Idaho. Main access into, and production from, the mine is via the Silver Shaft, a 5.5-m (18-ft) diameter, concrete lined shaft sunk by J.S. Redpath to an original depth of 1,890 m (6,200 ft) in the early 1980s. The shaft is divided into four compartments (Fig. 1), with sets made of 225 mm x 175 mm (9 in. x 7 in.) hollow structural section (HSS) steel buntons and 150-mm x 150-mm (6-in. x 6-in.) HSS dividers spaced every 4.5 m (15 ft) down the length of the shaft. Two skip compartments on the east side of the shaft are equipped with 125-mm x 150-mm (5-in. x 6-in.) HSS steel guides and 9-t (10-st) skips with three deck trailer cages for men and materials. The west side of the shaft is divided into a manway, and a fourth compartment that was originally designed for a service cage. Shaft services consist of a 250-mm (10-in.) a compressed air line and 150-mm (6-in.) sandfill line along the south side of the shaft, and 250-mm (10-in.) discharge (gray) water and 150 mm (6 in.) fresh water lines on the north wall. The mine?s primary 13.8 kV power lines, as well as communication lines are located on the west wall of the shaft. The production hoist is a 3.7-m (12-ft) diameter, double drum, double clutch, 2,238 kW (3,000 hp), direct current unit equipped, at the time, with thyristor drives. The 30-year-old drives would prove to be problematic during the rehabilitation project, leading to an upgrade to modern ABB drives later in the project, after the shaft rehabilitation was complete. The shaft had been subjected to the typical wear and tear of 30 years of operation, including intermittent sandfill and muck spills, and, in the lower areas, some corrosion. During those 30 years, the west compartment, originally designed for the service cage, could only be accessed from a work deck on top of the skips or from the manway.

By Jozef S. Stachulak

INTRODUCTION Conveyor belt fires represent a serious hazard in underground mines. This fact is well understood in most mining countries. The statistical data for Ontario mines (1) indicates that the majority of the conveyor fires occurred at the head pulley of the conveyor belt. The main emphasis for fire prevention and detection should then be concentrated at the drive pulley of the conveyor designed to transport non-combustible material. In the case of conveyor belt fires, it is of utmost importance to detect the hazard at an early stage, when the overheating has not yet reached the ignition point. Thermal noise detection sensors were installed in 1987 at several conveyor sites at Inco mines. PRODUCTS OF COMBUSTION THERMAL DEGRADATION OF CONVEYOR BELT Various investigations on conveyor belt fire hazards have been made in the past (2, 3, 4, 5, 6, 7). Several belt samples (6, 7) were subjected to thermal oxidative degradation. The belts used in these tests were neoprene, polyvinyl chloride and styrene-butadiene rubber (6). About 70 different compounds were identified in the volatile thermooxidative products. As expected, hydrogen chloride was the major toxic product formed, accompanied by relatively low quantities of other toxic compounds such as carbon dioxide, carbon monoxide, sulfur dioxide, carbon disulfide, hydrogen sulfide, benzene, chloroprene, cresols, chloroethanol, formic acid and C8 hydrocarbons. The research investigation (8) performed by the USBM indicated that "smoldering combustibles generate a very low level of CO compared to the level of smoke produced". The cited publication (8), states that, "During smoldering combustion, typical mine combustibles produce about 2.5 times more smoke than CO. As fires develop to their flaming stages, the trend reverses and about eight times as much CO is produced as smoke." The reader is referred to several significant sources of additional information pertaining to emission products that can be found in references (8), (9), and (10). ANALYSIS OF FIRE HAZARDS U.S.A. AND ENGLAND Nearly 15 percent of all underground coal mine fires in the United States involved ignition of conveyor belts (7). In many cases, the fires propagated through thousands of feet of belt entry and created losses in the millions of dollars. Some of these fires consisted of rubber belts. Some involved polyvinyl chloride and neoprene belts that were classified "fire resistant". Typically, a belt fire begins after the conveyor is stopped. The fire is initiated by burning coal dust and grease accumulation around defective rollers or belt drives that have become heated by friction (7). An analysis of 113 conveyor fires (11) showed that 41 originated at the driving pulleys, 32 at the defective rollers, and 40 elsewhere on the conveyor system. The severity of the fire, which can spread along a conveyor road, has been emphasized by the disaster at Creswell Colliery, Derbyshire, on September 26, 1950, when 80 men were overcome and killed by toxic fumes from the fire (12). The fire started from smoldering caused by friction, and developed into a flaming combustion, propagating along the roadway containing the rubber belt at an estimated speed of 40.2 m/s (90 mph), and travelling a total of 650 m (2100 ft) THE INFLAMMATION OF CONVEYOR BELTS THE MECHANISM OF IGNITION Defective operation of a conveyor belt may start a fire in several ways: - Friction of the belt on the drive pulley. - Jamming of a guide roller, and others.

Jan 1, 1991

By Raj K. Singhal

Canada is a world class producer and exporter of minerals and mineral products. Canadian open-pit mines are highly mechanized and use state-of-the-art equipment and support technology. During the past few years, productivity improvements at Canadian open-pit mines have been achieved by taking advantage of larger equipment, in-pit crushing and conveying, truck dispatch systems and electronic management tools. The most recent developments are related to hydraulic transportation and the application of global positioning systems (GPS). Mine planning has become computerized. Environmental issues are dealt with in all phases of planning. Equipment modifications are pursued with vigor to keep the equipment functioning in the hostile Canadian north. In 1997, the mining and mineral processing sector employed 370,000 Canadians, contributing $26.2 billion to Canada's gross domestic product (GDP). The value of production of the Canadian mineral industry, including coal, amounted to $19.1 billion in 1997. Gold remained Canada's leading mineral with production valued at $2.8 billion. This was followed by copper ($2 billion), coal ($1.9 billion), zinc ($1.6 billion) and nickel ($1.9 billion). [ ] Synthetic crude oil from oil-sands mining operations in Alberta represents an important part of Canada's petroleum production. In 1997, the value of synthetic oil production was $2.87 billion. Canadian oil-sands mining has contributed significant technology developments in Canada.

Jan 1, 1999

By W. M. Husslage

The permeability in the blast furnace shaft is adversely affected by low temperature reduction degradation of sinters. The fundamental cause is an expansion of the iron oxide phase resulting from reduction of hematite to magnetite. The present study showed that expansion behavior during the hematite / magnetite reduction step and the resulting microstructure are strongly influenced by the reduction temperature (viz. partial oxygen pressure), the reducing agent and the nature of the hematite. The reduction rate is of minor importance. A reduction mechanism is proposed, explaining the dilation behavior and the magnetite microstructure. The results can provide better insight into reduction degradation behavior.

Jan 1, 1998

By Kewal K. Kohli, Richard E. Thill, Syd S. Peng

The results of unpublished investigations into surface subsidence from coal mining in the Northern Appalachian Coalfield are summarized. These investigations were carried out by various coal companies and the State of Pennsylvania in the sixties and seventies. Subsidence data were collected and analyzed from 10 room-and-pillar panels in 5 mines in the Pittsburgh coal seam. Results show that angle of draw ranges from 26° to 33° and subsidence factor from 0.42 to 0.72; surface heating generally occurs beyond the edges of the panel, the amount and extent of which vary; waviness occurs in the subsidence profile if a substantial number of pillar stumps are left in irregular patterns; interpanel effect is significant; time-dependent subsidence exists, but varies for different panels; and surface slope does not seem to affect the amount of subsidence.

Jan 1, 1982

By Frank E. Sullivan

The separation of liquids from granular materials has been widely studied by a number of: investigators over a period of years in an effort to more fully understand the physical phenomenon which occurs. Liquid may be removed from solids, or partially removed, by gravity separation, mechanical separation' or heat drying. Mechanical separation is advantageous when compared to heat drying principally from a cost saving standpoint and also on certain materials which are heat sensitive. It is realized however that mechanical separation of liquids has certain practical limitations. In order to evaluate the efficiency of mechanical separation and predict the extent of, liquid removal, it is first necessary to study the forces which hold the liquid to the solids. From a very practical observation using gravity drainage, it is soon obvious that a pile of coarse solids will drain faster and retain less liquid than a pile of finely divided solids of the same material. For commercial operations it is important to estimate the residual liquid which will remain after a mechanical separation. Batel (1) explored the various quantities of liquid present in the interstices of the bulk granular material. From his work and other authors which he has correlated in one of his recent papers, various formulas are now available which permit an empirical relationship to be developed showing residual moisture versus mechanical separating forces.

Jan 1, 1965

By Joel L. Morrison

The preparation of coal-water slurry fuel (CWSF) has the potential to be a commercially viable technology for the coal industry. The technology base required to prepare stable CWSF using grinding circuits has been developed over the past decade and is now being applied to the preparation of CWSF from wet coal fines which are generated during coal beneficiation. When preparing CWSF, the optimum CWSF formulation must be determined to ensure that the fuel will be stable while having acceptable atomization and combustion properties, and the production run must be monitored closely to ensure that the CWSF quality is maintained. This paper describes the CWSF formulation process, CWSF preparation circuits, and some of typical problems encountered in, and solutions to, the transportation and storage of CWSF.

Jan 1, 1993

By Nelson Alonso Portal Ravichaua, Melissa Esther Mendoza Tirado, Raúl Arévalo Saavedra

This study analyzes the implementation of an integrated strategy for environmental education and community awareness in Cajamarca, Peru—an Andean region affected by climate variability and the public perception of miningrelated water shortages. In collaboration with the Interactive Water and Earth Museum and the Newmont ALAC Foundation, three-month campaigns were conducted in schools and local communities. Key topics included the water cycle, climate change, and water availability, linked to urban infrastructure projects that improved flow rates through strategically located tubular wells tapping underground aquifers. The initiative addressed the challenge of communication in a context where mining is often blamed for scarcity, fostering scientific understanding of contributing factors. The study highlights how science-based outreach and institutional collaboration can strengthen resilience and promote sustainable water stewardship in mining-influenced regions.

Feb 22, 2026

By C. G. Anderson

Extraction of valuable resources from complex orebodies will become more common. This is obvious for two reasons. First, the cleaner and more readily processed ores have continually been depleted through centuries of mining. Second, new technologies have evolved for effectively handling complex ores. One of these new processes has been in place at Sunshine since 1984. Based on sulfuric acid oxygen pressure leaching with nitric acid as an oxidizer, this patented technology allows silver and copper to be efficiently recovered from a complex sulfide concentrate. As efficient as it is, this process represents novel technology found nowhere else on an industrial scale. As such, a research program was undertaken in 1989 to optimize this leach process and to better understand it. From this study, several potential plant improvements were found and recommended. As a result, two of these options, nitric acid replacement by sodium nitrite and concentrate regrind are now used in day to day operation at Sunshine. Patenting of these changes was recently accomplished (1). Thus, the development, perceived mechanisms, plant integration and potential applicability of this technology will be covered in this paper.

Jan 1, 1994

By J. M. Rebstock

Recent re-classification of crystalline silica as a potential human carcinogen has resulted in a new limit of 0.1% free silica in bulk powdered minerals. Detection of silica at this level can be expected to severely challenge or exceed the capabilities of existing protocols for x-ray diffraction, the traditional method for free silica determination. Automated SEH-EOS analysis provides an attractive alternative method, with direct analysis of individual particles for the determination of the concentration of free silica, and a direct measurement of silica particle sizes. This paper will discuss automated SEH analytical procedures, sample preparation, and statistical considerations.

Jan 1, 1990

By Shaojun Bai

Siderite ore with high phosphorus content was reduced isothermally at 1,050° C with pulverized coal and different dosages of sodium carbonate. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energydispersive analysis of X-rays (EDAX) were used to characterize the samples. The influence of sodium carbonate on the carbothermic reduction process was investigated. Sodium carbonate and its dosage played a considerable role in the carbothermic reduction. The iron particle size in the reduced ore was below 20 µm, and fayalite was abundant without sodium carbonate additive. With a mass ratio of Na2CO3-to-ore of 5% additive, the iron particle size in the reduced ore was generally above 50 µm, and the diffraction intensity associated with metallic iron in the XRD pattern increased. The effect of sodium carbonate on the phase transformation of fluorapatite during carbothermic reduction was also addressed via thermodynamic calculations and aqueous leaching experiments. The results showed that the fluorapatite was not reduced to P2 at 1,050° C, and a portion of the fluorapatite was converted to soluble phosphate. The reduction of siderite can be catalyzed by adding an appropriate amount of sodium carbonate. This catalytic activity was caused by an increase in the reducing reaction activity of FeO and the acceleration of the carbon gasification reactions. The decrease in phosphorous content in the iron concentrate was attributed to an improvement in the separation of the iron phase from the slag phase when sodium carbonate was added and with the formation of soluble phosphate.

By D. Robert Weir, Verner B. Sefton

The reduction roast-ammonium carbonate leach-hydrogen reduction process for laterites has been under development by Sherritt Gordon for the past 20 years. The process can treat high iron or low iron laterites, with some process modification, and gives extractions of 88-93% Ni or 82-88% Ni, respectively. Five campaigns on a 1 tonne per day Pilot Plant and four campaigns on a 35 t/d Demonstration Plant have been carried out on laterite from three different deposits, and many other laterites have been investigated in the laboratory. The Marinduque Surigao Nickel Refinery in the Philippines was designed on the basis of this work. The process comprises roasting to selectively reduce the nickel and cobalt in the laterite, leaching the calcine in ammonium carbonate to dissolve the metals, recovery of cobalt by precipitation of a mixed metal sulphide, concentration of nickel from the carbonate solution by basic nickel carbonate precipitation and recovery of high purity nickel by hydrogen reduction of nickel from ammonium sulphate solution. Ion exchange has been developed as an alternative to BNC and for recovery of trace nickel from BNC barren liquor. Details of the development of some of the process steps through the laboratory to commercial plant are discussed. The process metallurgy has been confirmed in the commercial plant.

Jan 1, 1979

By Bruce D. Hebb, Shahin Shadlou

Fiber Reinforced Polymer (FRP) is an excellent material choice for a broad spectrum of corrosive fluids and, in many cases, offers the best value per dollar. FRP Flanges present the greatest design challenge of all standard piping components. The theory underlying the design of flanges is very complex. In addition, due to the nature of FRP material, proper fabrication of the flanges is as critical as the design. In this review, the challenges of making FRP flanges along with the design techniques and best practices of fabrication that will lead to a high-quality flange will be discussed.

Feb 1, 2024

By C. Y. Haas

Of all the industrial clay minerals, attapulgite probably enjoys the widest variety of applications. A review published over three years ago by Haden and Schwint (18) cited some 80 individual uses, a list which continues to grow. In its near half-century of commercial life, attapulgite has received a generous share of research study and patent development effort, both on the part of producers as well as consumers. This work has been divided between understanding the mineral's structure or properties and applying it to specific end-uses. Naturally, information gained from the former has pointed toward opportunities in the latter. References of particular significance are cited throughout the text. Attapulgite's variety of uses derives from the unique three-dimensional structure and needle-shaped particle form of this crystalline hydrated magnesium aluminum silicate. Its inherent colloidal and sorptive properties are well known, and distinguish it from its sister clay minerals. Attapulgite is characterized by its high surface area, porosity, sorptivity, and decolorizing power. Its slips or slurries are viscous and thixotropic, however, unlike bentonite are not flocculated by electrolytes. In Table I are compared the general properties of attapulgite, bentonite, and kaolin. The properties in Table I are documented in greater detail by the wealth of scientific literature which has been published on the composition (14)(15), structure (6)(16), surface (16)(4)(22)(24), adsorption (31)(4)(5)(25), rheology (10-11)(12)(13)(26)(27)(32), plasticity (30) (31), and chemistry (23)(3)(7) of attapulgite. Attapulgite is the principal mineral constituent (70 to 80%) of attapulgite clay as it is commercially produced in the Georgia-Florida area of the United States. As mined, this clay also contains 10 to 1S% montmorillonite, sepiolite, and other clays; 4 to 8% quartz, and 1 to 5% calcite or dolomite. (18) During processing, non-clay fractions are removed so that commercial products are enriched to 85 to 90% attapulgite. By wet processing (such as practiced in the

Jan 1, 1971

By Walter B. Hester

All persons and communities that have experienced strong-motion earthquakes are convinced of the importance and complexity of earthquake problems thatmust be solved in order to reduce the personal hazards and property losses to a reasonable minimum. It is also clear that absolute elimination of all risks is impossible. Reduction of existing hazards and precautionary measures which will minimize chances for disaster can be accomplished by realistic appraisal of the effects of recent earth- quakes on modern structures and installations. Localities that have reason to expect so-called strong- motion earthquakes can anticipate these effects by taking appropriate steps. Valid earthquake information can only be obtained from earthquakes. Each earthquake contributes to the body of knowledge by additional facts and by clarification of previous observations. Rational interpretation of the data followed by practical application of the conclusions can contribute greatly to the safety of persons and property. The general public expects the architectural and engineering profession to accept this obligation and render this service. Most earthquake hazards are man-made and arise from the imperfections of the works of man and his failure to anticipate the consequences when the natural characteristics of his environment are ignored. If it is not given to man to prevent such natural phenomena as earthquakes, it is sometimes within his power to control their destructive effects and to reduce to a minimum the toll of life and human suffering.

Jan 1, 1958

By Sunil Bodakunta, Sreenivasa Rao Islavath

The abstract highlights the importance of determining the optimum line of extraction in continuous miner workings for improved safety and productivity. The study investigates three extraction techniques (diagonal, straight line along strike, and straight line along dip-rise) using 3D numerical modeling. The dip-rise extraction technique is found to be optimal due to lower stress and displacement, leading to a higher safety factor. The research also develops a continuous miner stability index (CMSI) to predict working face stability based on mining depth and pillar width-to-height ratio.

Apr 28, 2022