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By N. Rowlands

The importance of mineralogical and chemical characterization of fine particles in the fields of mineral and metallurgical processing is discussed. Emphasis is placed on electron beam analysis techniques including electron diffraction and energy dispersive analysis with special reference to the scanning trans- mission electron microscope. The correct choice of instrument depending upon particle size, composition and nature of sample is stressed and the analytica1 capabilities of different types of instruments are evaluated. Recent applications of electron beam equipment to processing problems are presented and the paper concludes with a review of new developments in the fields of surface analysis and micro-diffraction.

Jan 1, 1985

By Danny Chan, Shahram Tafazoli, Nicholas Himmelman, Edmond Chow

"While wearable technology has been garnering attention in the consumer market, enterprise and industry have just begun exploring its potential applications. Since February 2014, Motion Metrics International has been working in collaboration with Vandrico Solutions Inc. to apply wearable technology to improve productivity and safety in the mining industry.This article discusses the value proposition of using wearable technology to deliver critical notifications in mining. The advantages and disadvantages of various form factors are explored. The challenges, both specific to mining and in general to wearable technology, are defined. Finally, the concept of MetricsGear, the first wearable technology platform developed for mining by Motion Metrics International in collaboration with Vandrico Solutions Inc., is described. MetricsGear is designed to notify the user with minimal distraction to keep the user focused on his or her primary task and aware of mission-critical events. This focus and awareness allows the user to work more efficiently and safely. The mining process consists of a series of intricate stages, where certain events or conditions in one stage can have a huge impact on other stages. The notification of these critical events or conditions is vital for ensuring the overall efficiency of the mining process. Critical notifications can be classified as two types: timecritical events and contextual information. Time-critical events are situations where a timely response from a responder can have a significant impact on seizing an opportunity or mitigating cost. Some human-computer interaction (HCI) experts classify notification types based on the interruption, reaction and comprehension (IRC) framework. Time-critical events are classified to have high interruption, high reaction and low comprehension due to their urgency. The responder should have just enough information to identify the crisis and react as soon as possible (Chow, 2014). For example, when a tooth is lost during shovel operation, it is necessary to recover the missing tooth before it jams the primary crusher. The consequence of missing this critical time period is a jammed crusher that can cause the mine to be out of production until the jammed tooth is extracted (Baumann, 2013). In this case, the responder only needs to see an image to confirm if the tooth is missing and information to identify which equipment and when the tooth went missing (Fig. 1)."

Jan 1, 2014

By Charles W. Axten

Since the mid-1970s, samples of airborne and waterborne fibrous particulates have been collected in the area of the Northshore Taconite Ore Processing Facility by the Minnesota Department of Health (MDH), the Minnesota Pollution Control Agency (PCA), and the University of Minnesota. Indirect sample preparation has consistently been used although other aspects of the sampling methods and sites have varied and analytical procedures were altered over time as more accurate and precise microscopy methods were developed (i.e., phase contrast optical microscopy, transmission electron microscopy, transmission electron microscopy with energy dispersive spectroscopy). In the mid-1970s, levels of airborne fibrous particulate in the Silver Bay area averaged from 0.00030 to 0.03 f/ml. This level was significantly greater than levels of similar particulates in the St. Paul, MN area, although two of the Silver Bay sampling sites, considered individually, did not indicate levels of fibrous particulate markedly different than that seen in St. Paul. More recent sampling data (i.e., 1990?2001) indicate mean concentration of airborne fibrous particulates (amphibole-like fibrous particulates) of 0.0020 f/ml with a range of values from 0.0001 to 0.0140 f/ml. Such levels are not significantly different from those seen in other non-urban environments in the US and Europe. Concentrations of fibrous particulates in water samples were higher in the mid-1970 when iron ore tailings were being deposited in Lake Superior, but since the tailings have been deposited on land waterborne levels of fibrous particulate in the Beaver River have remained relatively constant averaging in the range of 7.5 MFL. This level is only slightly in excess of the current EPA drinking water standard for fibrous particulates. Review and consideration of this data is important in determining the potential health risks associated with airborne and waterborne fibrous particulates in the areas of the Northshore Taconite Ore Processing Facility. © 2007 Elsevier Inc. All rights reserved. Keywords: Taconite; Asbestos; Asbestiform fibers; Fibrous particulates; Cleavage fragments; Phase contrast optical microscopy; Transmission electron microscopy

Jan 1, 2007

By P. A. Korpi

In March of 1978 the first set of Angular Spiral Liners utilized in grate discharge ball mills for wet grinding was put into service in the San Flanuel Concentrator of Flagma Copper Company. The use of these liners has decreased grinding media consumption by 19.2% and grinding energy consumption by 15.8%. In addition a 1.1% increase in grinding throughput is being realized through the use of the system. This paper describes the Angular Spiral Lining System and reviews the test program at the San Manuel Arizona Concentrator. Operating parameters are discussed in addition to the current testing program to futher optimize the system.

Jan 1, 1982

By Deepak Malhotra

Following a severe recession in the early 1980's, mining companies have taken significant steps to improve metallurgy and reduce operating costs. They do not view chemical reagents and the long-term relationship with reagent producers the same way they did two decades ago. This paper discusses the general perspective of changes that have taken place over the years, especially with respect to cost of production, selling price and environmental constraints. A cooperative program between the consumers and producers of chemical reagents is recommended to understand each other's problems and identify the present and future needs of the mining industry. This approach will be beneficial to the long-term survival of both parties.

Jan 1, 1994

By Hassan El-Shall, El-Sayed A. Abdel Aal

The major goal of this study is to decrease iron content in wet-process phosphoric acid. Reducing the amount of post-precipitated sludge in the acid is another important objective in this investigation. In order to achieve these goals, research efforts have focused on bench scale testing of an iron-chelating reagent to remove iron from phosphoric acid produced from South Florida high-iron and -magnesium phosphate concentrate, and plant testing using freshly produced concentrated acids for reducing the post- precipitated sludge. The data obtained in the above studies suggest that the addition point of the precipitating reagent is very important, as the precipitated iron compound has higher solubility at higher P2O5 concentrations. Up to 60% Fe2O3 removal efficiency is achieved depending on the amount of the reagent, concentration of acid used, and operating conditions. The addition of precipitating reagents to freshly concentrated phosphoric acid leads to a decrease of up to 84% in sludge volume percentage depending on acid type and clarification conditions. Decreasing the volume percentage of the sludge facilitates acid handling as well as decreases the adherent water- soluble P205 leading to lower total P2O losses.

Jan 1, 2002

By J. M. Mutmansky, B. Kolonja

A PC-based simulation model using the software packages SIMAN and CINEMA was developed to simulate and animate truck-shovel operations. The model is capable of simulating one mathematical dispatching strategy using linear and dynamic programming and six heuristic dispatching strategies. Data were collected from an actual operating mine through time studies and analysis of historical records. Statistical analyses were performed, and appropriate theoretical distributions were fitted for various time events in the truck-shovel cycle. The model was then applied to study overall impact of these dispatching strategies on constrained and unconstrained mine productivity. The simulation/animation model developed in this study seems to be an efficient planning tool for choosing optimal fleets and finding an optimal dispatching strategy to produce an equilibrium between the quality and quantity of production.

Jan 1, 1995

By A. Dale Wunderlich

In the past, most people have associated gold scams with the sale of non-existent gold mines, an undivided interest in unmined ore or the sale of gold-plated lead bars. These scams are still available to those who want to speculate. Now, though, the mining industry is plagued with a new type of con artist. Many of the new scams involve large, well established mining companies being victimized. Nearly all legitimate mining companies are in search of good mining prospects. This makes them susceptible to modern day con artists. Many professionals from the mining and petrochemical industries are out of work. Some of them have gotten involved with scams or activities that border on the criminal. Mining companies are losing millions of dollars each year to scams. Some of these scams involve venture-capital fraud. Some involve fraudulent mining proposals. And some involve unqualified individuals who are providing services by the precious metals industry. The author estimates that mining scams may be costing precious metals companies as much in dollar losses annually as employee theft. Employee theft is at an all time high, but so are gold scams. Since January of 1990, the au¬thor has been involved in gold theft investigations in which more than $1 million in gold product has been stolen by employees. In the past, most of the gold mine scam operators have concentrated on the general public, which is generally ignorant of basic mining procedures and practices. A scam artist would tell someone from your neighborhood that they have a wonderful underground mine. It produces 62.2 kg/t (2000 oz per st) of gold ore. Your neighbor might think that sounds like a very good investment. Those involved in the mining industry know better.

Jan 1, 1990

By Walter E. Heinrichs

To many, petroleum exploration and successful geophysics , are partly synonomous, This is not because natural petroleum is usually concentrated as a liquid, nor certainly not because oil can be detected directly. The reason is Chat geophysics helps to at least better understand and sometimes, to even explain the essential geology involved. That groundwater is similarly a liquid with all but a few of its basic geologic relationships practically identical to petroleum, seems to have escaped many of those most interested and responsible for complete geo-hydrologic knowledge. The paramount need to use every means at our disposal for maintaining and expanding our crustal resources reserves are generally obvious, However, in view of the rapidly mounting requirements, continual re-emphasis is worthwhile.

Jan 1, 1963

By Ed Schodowski

Wireless technology is a hot topic for anyone involved in the design, operation, maintenance or upgrading of mines or mineral processing plants because wireless technologies overcome barriers that have prevented many useful data inputs. Wireless communications can contribute to worker safety, satisfy environmental concerns, support plant security, track human and physical assets, and improve equipment maintenance. The cost structure of wireless is compelling and users can realize savings ? up to 90 percent less installed cost than wired instruments ? since wireless technology eliminates the need for expenses associated with cabling, engineering, construction and documentation. Many applications previously considered too expensive have become economically feasible with wireless. Two examples are continuous monitoring of safety showers to notify operators when one has been activated, and monitoring effluents to ensure environmental regulations are being met. In many cases, wireless transmitters can be installed where wired devices were too expensive to justify, or were not feasible due to physical or technical barriers. Examples include monitoring temperature measurements inside a rotating reactor or monitoring process variables in a tough, corrosive environment too challenging for a wired solution. Wireless also gives operating personnel mobility with the ability to communicate from remote or hard-to-reach zones. According to a recent Venture Development Corp. survey covering radio frequency (RF) of microwave industrial monitoring and control products, these features are contributing to the expected nationwide growth rate for industrial wireless applications of 19 percent annually from 2007 to 2012 (Taylor, 2008). At the same time, mineral producers have many questions about wireless systems including their applicability, reliability and security in this industry. Just what can wireless do? Is it secure and reliable? Can these instruments stand up to the rigors of the industry? Can wire-less technology provide the flexibility needed for mining applications?

Jan 1, 2009

By F. J. Susko

The Bureau of Mines applied a flotation model to the hydrodynamics of the Bureau-developed rapid flotation system. Rapid flotation is a process which separates the bubble-particle attachment and froth-pulp separation stages of the flotation sequence into two discrete unit operations allowing the operations to be individually optimized. Both an air-injected hydrocyclone and an in-line mixer were used as the bubble-particle attachment unit and a shallow-depth froth separator was used to separate the ore-laden froth from the pulp. A 10-L/min batch system was tested on a coarse coal feed sample. The system was tested using two different bubble-particle attachment units at various aeration levels in order to test the flotation model. The results of the flotation model reflect general trends observed in the experimental data.

Jan 1, 1993

By D. H. Lynch

This paper is a general description of current Central Florida phosphate mining, beneficiation and product transportation. It is directed and believed to be of interest to engineers not familiar with this industry.

Jan 1, 1978

By Michael Li, Kathryn Rogers, Arie Moerman, Mike Cooper

The Brunswick Mine, a Division of Noranda Inc., produces zinc, lead, copper, and bulk lead-zinc concentrates through underground mining of a large massive sulphide deposit. The mining method employed is longhole open stoping with delayed backfilling. In 1996 Brunswick began a review of its mining methods and backfilling operations. In 1997 the decision was made to convert the backfill system from cemented and uncemented rockfill to paste backfill prepared from mill tailings. This paper will describe the features of the backfill preparation and distribution systems, review the handling of technical issues, and discuss experiences since plant commissioning.

Jan 1, 2001

By F. Woller

The territory of Czechoslovakia is well endowed in deposits of a variety of industrial minerals. At present, 29 different types of industrial minerals are mined from some 600 individual deposits in Bohemia and Moravia only. About half of those production centres involves structural materials like aggregate and common brick clays and loams. A significant proportion of industrial minerals produced in Czechoslovakia are exported. Destinations of main products are shown in Figure 1. Production of industrial minerals in Czechoslovakia has a long history. Glass has been produced since the 14th century, sulphuric acid since 1578, graphite since 1750, and chinaware since 1790, to name just a few; but most of the present production comes from deposits developed during the past forty years. For a variety of reasons, only about 30 per cent of registered and explored industrial minerals deposits in the country are in production (Table 1). Two of the reasons may be the complexity of processing or conflicting interests of parties involved, but lack of market research, investment funds, or processing capacity have also had an impact on the level of utilization of the resource base.

Jan 1, 1992

By Koji Nakanishi, Masayoshi Karasawa, Yasuhiro Morimoto

"Shin-Yokohama station (tentative name), one of the station of the Sotetsu - Tokyu through line (ST line), is under construction by the OPEN – CUT method. The Underground Soil–Cement Steel Diaphragm Wall is implemented as an earth retaining wall. This earth retaining wall is utilized as a main body of a subway station. It is the first time to utilize this earth retaining wall as the main body. There are two difficult issues for this project. One is that this station is planned under busy major road and there are many underground utilities, for example, an electrical transmission line. Because of that, construction area is limited. The other is that this station is located in a thick soft clay layer. This layer has a high risk of consolidation settlement because of draining during main excavation. Thus, high water tightness is required for this earth retaining wall. This paper reports design and construction methods for the Underground Soil–Cement Steel Diaphragm wall introduced as a part of the body of the subway station.1. OUTLINE OF SHIN-YOKOHAMA STATION 1-1. Location and structure of Shin-Yokohama Station Shin-Yokohama station is an intermediate station on the ST line connected to the Tokaido-Shinkansen bullet train, the JR-Yokohama line and the Yokohama Municipal Subway. Access to Tokyo and the Tokaido- Shinkansen from the eastern part of Yokohama city will be improved by this project. In addition, the number of estimated passengers of this station is one hundred thousand people/day because a soccer stadium (Nissan Stadium: 72,000 people), a huge indoor arena and a hotel are located in this area. This station consists of 4 stories and 3 spans (Max width; 29m, Depth; 33m, Length; 325.5m). Completion image is shown in Figure 2. Generally, stations have 1 platform and 2 trucks. But this station has 2 platforms and 3 tracks because some of ST line trains return at this station and a train deadheads from Hazawa station to this station in an emergency. This station is planned as 4 stories underground station, and the platform is on the lowest story. The reason why this station is in such a deeper position is to prevent the alignment from interfering with the Yokohama Municipal Subway station and foundation piles for bridge piers existing along the alignment. Even under the constraint conditions, earth covering should be shallow as much as possible. As a result, the tunnel edge is very close to the foundation pile, and the gap is only about 2m (Figure 3). In addition, passengers will be able to change trains easily from the ST line to the Yokohama Municipal Subway or vice versa at this station."

Jan 1, 2016

By A. C. Kunkie, C. J. Marshall

Highly delaminated muscovite mica products (WG-1 and WG-2) have been developed by J.M. Huber Corp. The micas are characterized as a 325-mesh product having high brightness and very narrow particle size distribution. At 40% loading in polypropylene, WG-1 mica provides substantial improvement in tensile modulus and equal tensile strength to unfilled polymer; in high-density poly- ethylene (HDPE), WG-1 provides four times the tensile modulus and a 50% increase in tensile strength over unfilled polymer. Surface modification of the water-ground mica (SM ™) provides substantial improvement in tensile strength over untreated mica at greater than 20% loading in polypropylene; in HDPE, tensile strength is twice that of unfilled polymer.

Jan 1, 1988

By N. M. Levine

This work defines and systematizes the physical factors of the problem of leaching and demonstrates for the first time the utility of macropore volume, micropore volume, specific surface, pore size distribution and permeability as parameters of leaching based on a study of the recovery of uranium from the Top Black member of Chattanooga Shale.

Jan 1, 1962

By Ingo Kaundinya

"INTRODUCTION Tunnels are important elements of the German federal road network which have to cope with an increasing traffic load especially of heavy goods vehicles. In order to ensure a high availability and safety level for these key infrastructures, big efforts are required by owners and operators in order to keep all infrastructures up to date. This mainly relates to current European regulations regarding tunnel safety (Directive 2004/54/EG) [1] and their national implementation, which must be fulfilled by many existing tunnels. In this context the German Federal Government spends more than 1.1 billion € for the structural and operational retrofitting of more than 120 existing road tunnels. As many of these projects have recently been finished or are still under progress, experiences and best practices could be reported. After the description of current requirements in national standards regarding structural fire protection, the paper gives an example for an upgrade of a tunnel’s fire protection by installing an additional fire protection system, which is a quite costly measure. Another possibility to fulfill current requirements regarding structural fire protection could be the numerical proof of sufficient bearing capacity of a structure. The influence of different fire loads and fire durations on the bearing capacity of typical road tunnel structures have been investigated in a research project funded by the German Federal Ministry of Transport (BMVI) and coordinated by the Federal Highway Research Institute (BASt). The results of this research project have been used to define a procedure how to investigate existing tunnels regarding structural fire protection. Finally, the research results have also been the basis for a current update of national standards for tunnel construction. REQUIREMENTS REGARDING STRUCTURAL FIRE PROTECTION The structural fire protection design of road tunnels is usually based on temperature-time curves of exposure to fire, for simplicity called ""fire curves"". The fire development after fire growth is illustrated with fire curves. Fire curves can be subdivided into a heating-up phase, a fully developed fire phase, and if applicable, into a cooling-off phase (cf. Figure 1). During the fully developed fire, the fire remains at a certain temperature level."

Jan 1, 2016

By Henri Letient, Tom Aley, David Evans

Antamina is a large open-pit copper and zinc mine located within the Central Andes of Northern Peru at an altitude of 4300 masl. The facilities are situated within the headwaters of several watersheds, within the Amazon basin. Nearby villages rely heavily on springs and streams for drinking and irrigation water. The principle source of baseflow during the dry season is from Cretaceous karstic limestone aquifers. Antamina will produce nearly 1.4 billion tonnes of waste rock over its mine life. Finding suitable sites for storing large volumes of waste rock is often a challenging task – especially in karstic, alpine terrain. Detailed hydrogeological investigations are essential for delineating the karstic hydrogeologic watersheds associated with the proposed waste facilities, which are often very different than topographic (hydrologic) watersheds. Contamination vulnerability mapping at Antamina consisted of geological and karst mapping, geophysical surveys, geochemical testing, dye-tracer studies, drilling and aquifer testing. Detailed mapping followed by dye-tracer studies proved to be the most cost-effective methods for characterizing the karst aquifer systems. The results were used to optimize waste rock management at the site to minimize potential impacts on groundwater resources.

Jan 1, 2005

By P. D. Chamberlin

Agglomeration for the heap leaching of gold and silver ores can be defined as the process of attaching fine ore particles (less than 100 mesh) to coarser particles so the fines are immobilized and uniformly distributed throughout the heap, thus making the heap more porous and uniformly permeable to the flow of a leaching solution. Agglomeration techniques and equipment to be described include drum and disc agglomerators, stockpile and belt agglomeration, and the use of vibrating deck and reverse running conveyors.

Jan 1, 1986