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By F. Castelli

A simplified non-linear method to predict the behaviour of a single pile and/or pile group under horizontal loads is presented in the paper. The evaluation of the non-linear lateral deflection is based on a procedure taking into account the decrease of the model stiffness with the increasing of the applied load. The solution derived firstly for the single pile, was extended to the case of a pile group introducing the p-multiplier (fm) concept proposed by Brown et al. (1988).

Jan 1, 2006

Background: Frictional ignitions continue to be a problem facing the U.S. underground coal mining industry. Many methane igni-tions are associated with the impact of mining machine cutter bits on quartzitic material (e.g., sandstone) during the coal-cutting process. Most ignitions result in small methane-air fireballs often only a few feet in size and limited to the cutter head location. However, under certain conditions, frictional ignitions can lead to larger methane explosions and/or fires with the potential for causing serious injury or death to the mining machine operator and other nearby miners. The requirements for a frictional ignition are a flammable volume of methane-air and an ignition source. This source is usually the hot streak caused by the frictional impact of the mining bit on hard rock, and the frequency of occurrence increases with increased bit wear. Another possible ignition source is the fric-tional impact of rock on rock during a roof fall.

Mar 1, 2008

By Oliver Finn

Gold dredging has made such rapid strides of late and there is such a widespread interest in this branch of mining that I venture to contribute a detailed account of the way in which a Keystone driller was used by me in California to loosen, by blasting, a very tight gravel deposit, preparatory to dredging. There is a great difference between “cemented gravel” and “tight gravel.” A truly cemented gravel is not a dredging proposition, while the tightest possible gravel, where there is no cement, can be made easy working by the following method of blasting:

Jan 1, 2008

By Edward J. Chuhta, Joseph E. Chilton, Robert J. Timko

in underground mines to measure worker exposure to various gases such as methane, carbon monoxide, and nitrogen dioxide (NO2). Even in relatively small concentrations, NO2 can produce harmful side effects in underground workers. Mines using equipment powered by diesel engines, carrying out explosive blasting operations, and performing extensive arc welding and/or cutting work will have measurable quantities of NO2 released by these processes. Workers in these areas often use gas monitors to warn of excessive gas concentrations and to help them determine when to increase ventilation air that will dilute these gases, thus minimizing exposures to this gas. Portable gas monitors, used to measure NO2 levels, must be calibrated before each use. Calibration is typically performed using a small portable pressurized cylinder containing a certified gas mixture. The certified NO2 standard mixture, usually 10 ppm NO2 concentration, is diluted with either air or nitrogen gas. To determine the stability of commercially available portable gas standards, two different cylinders containing NO2 in nominal 10-ppm concentrations were examined. One cylinder was diluted in air, the other, in nitrogen. Baseline NO2 mixtures were generated using a standard liquid NO2 permeation tube operated at a constant temperature. Final dilutions of the test gas mixtures were made with air or with nitrogen using a mass flow-controlled gas dilution system. This study showed that, when a permeation-type NO2 generator is used, the electrochemical sensors in portable NO2 monitors provide identical results for gas mixtures whether they are diluted with air or with nitrogen. Two different gas monitors, one with a two-electrode sensor and one with a three-electrode sensor, were used to measure gas concentrations in the two commercially available cylinders. One month after the cylinders were delivered, the NO2-in-nitrogen cylinder, stated to contain 10 ppm NO2, measured 8.13 ppm. The NO2-in-air cylinder, also stated to hold 10 ppm NO2, measured 6.88 ppm. Therefore, before using NO2 gas cylinders to calibrate monitors, it is recommended that their concentrations be verified either by manufacturer recertification or by comparing the stated cylinder gas concentrations to a laboratory-based permeation tube-generated standard.

Dec 1, 2005

By Juan Antonio Huamán Fernández

De acuerdo al estudio que realizó la Dirección General de Minería del Ministerio de Energía y Minas en el Perú, las estadísticas de accidentes fatales reportadas a escala nacional en el 2002 indican que la mayoría de accidentes fatales ocurridos en mina subterránea corresponden al 40% de desprendimientos de roca. Por lo cual, las empresas mineras preveen un programa basado en el desarrollo de la técnica de Gestión de Riesgos, que les permita un control en la seguridad del proceso. En este sentido, el presente texto desarrolla una técnica que identifica los diferentes factores que intervienen en los riesgos principales a través de los riesgos asociados; es decir, cuáles son esos riesgos asociados que influyen negativamente en cada una de las tareas que puedan causar accidentes.

Jul 31, 2003

By I. Tsolas

This paper presents the use of non-parametric approach (i.e., data envelopment analysis, DEA) for the development of environmental sustainability indicators in mineral processing using environmental, economic and/or integrated indicators (i.e., indicators that interrelate two dimensions of sustainability). A case study based on real publicly available data is presented to illustrate how the proposed approach can be implemented in practice. The merit of this approach, which is based on the productive efficiency framework, is that it provides environmental sustainability indicators that can be used internally for benchmarking purposes and externally for sustainability reporting.

Jan 1, 2008

By F. C. Harris, S. J. Gaab, J. Sattarvand, S. Duzgun

Underground mines are inherently dangerous due to potential hazards such as fires, explosions, and caving of rock. Although these events are rare, once they occur a speedy and safe egress of mineworkers is critical to survival. Static evacuation systems use exit signs or directional lines but can get obstructed or be hardly visible in smoky or dusty conditions. This paper presents the investigation of the effectiveness of a smart evacuation technology in underground mining, where a real-time guidance system leads individuals on an optimised path to the egress while avoiding danger zones, compared to conventional practices. Participants simulated an evacuation from a virtual reality mine, using the conventional system and the smart evacuation system with real-time guidance. The highest reduction in evacuation time using the smart method amounted to nearly 40% on average. Moreover, 83% of participants preferred the smart guidance system, and agreed that it could enhance safety.

Sep 1, 2021

By Bill Williamson, Doug Richmond, Kerri Kuntz, Gus Gilman, Larry Heywood

This was a description by the poet of what occurred over two centuries earlier to Hannibal’s troops as he passed through the Alps. Interestingly, the pass that many feel is the route that Hannibal chose, Col de la Traversette, is the sight of possibly the earliest avalanche mitigation known. Monastery records describe a tunnel built in 1470, near the top of the pass designed to protect pilgrims from the upper slopes. For the next several centuries, avoidance and reinforced structures were the primary tactics to defend from avalanches

Jan 1, 2009

By T F. McConachy, B I. A McInnes, R A. Binns

Within the last decade, major research discoveries have been made in the submarine realm of magmatic and hydrothermal activity of arc-backarc systems in the southwestern Pacific. These include identification of numerous particulate-poor, gas-rich (CO2-CH4) hydrothermal plumes emanating from arc front volcanoes, actively forming porphyry-copper-gold style mineralisation, and new backarc spreading systems erupting alkali basalt-trachyandesite magmas. Major goals of these studies have been identification of modern analogs to ancient volcanogenic massive sulfide ore bodies, and quantification of the volatile fluxes though supra-subduction zone systems.

Jan 1, 2002

By M. Santillan

Minerales Monclova S.A. de C.V. (MIMOSA) has applied different methane gas drainage technologies, according to the top industry requirements in order to keep the methane gas at the lowest possible concentration in our operations, both in the development sections and longwall sections. Our staff has used the horizontal rotary technique. In 2004 MIMOSA bought a re-built drill machine and signed a contract with Resource Enterprises Inc. (REI), which included a training program in Horizontal Directional Drilling using the reflex system. The training system was developed for a period of three months in Mine VII, with very good performance by the MIMOSA staff. After the training the equipment was moved to Esmeralda Mine, where we had already drilled holes at the development section, 2,500 ft. It was the longest distance that could be reached with our original equipment, obviously; the directional drilling program is another challenge for us and our staff, but we are very confident that our result will be better every time. We will be evaluating each borehole and expect to improve our results in each progressive borehole, until we can drill up to the capacity of the equipment. We are in the process of buying another drill with an electronic monitoring device (DD DMecca) in the following months.

Jan 1, 2009

Study on Iron Ore Sintering with High Proportion of Specularite Concentrates Specularite iron ores have poor hydrophilicity and ballability as well as bad high-temperature reactivity, which restricts the large-scale application in the sinter and pellet production. In order to make the best use of the specularite concentrates, a novel process of Composite Agglomeration Process (CAP) is applied in this research. By the CAP, the percentage of specularite concentrates in the sinter mixture is increased to no less than 40 per cent as well as the coke breeze dosage is reduced by 0.3 per cent~0.6 per cent. Moreover, all the sintering indexes are obviously improved compared with the traditional sintering process. Researches on the metallurgical performances shows the finished composite agglomerates are high-quality burdens for blast furnaces. This investigation can provide an effective route to utilize the inferior specularite concentrates in the sintering.

Sep 13, 2010

By Charles O'Connor, Ben Tisa

International Training Resources is a company consisting of personnel with extensive law enforcement and military special operations experience, The staff members are qualified to train and certify, assist and advise law enforcement officers and agencies, at any level, in critical incident policy, procedures and tactical resolutions. Successful critical incident resolution is comprised of many elements of professional skills and personnel. (Command staff, negotiators, snipers, tactical teams, uniform patrol, K-9, bomb squad, etc.) Recently, tactical teams have been developing the capability for the use of explosive methods for rapid entry into crisis locations. This document ‘will briefly describe the environment, operational issues and courses of action associated with developing a complete tactical breaching program for utilization by SWAT teams in response to operational conditions in critical incident situations. This topic is being presented to the I.S.E.E. evaluators under “Interesting Blasting Projects” and “Public Relations” categories. Tactical operations differ significantly from traditional industry practices and we appreciate the opportunity to show the industry other professional applications of explosive materials and techniques. Presently, of the few schools from which law enforcement officers can receive training with explosive breaching methods, International Training Resources is the only company currently teaching and certifying officers which has received total endorsement by the California Peace Officer’s Standards and Training Commission (P.O.S.T.) and the state blaster’s licensing commission. We have pioneered the combining of law enforcement needs and blasting industry technology to train tactical officers, nationwide, in the mission essential skills necessary for explosive breaching.

Jan 1, 2000

By E. Kuipa, J. N. Lekunze

The selection of an underground mining method stems from a multivariate analysis that considers geomechanical, geological, economic, and operational parameters. Even after identifying the most compatible method, there is no assurance that the mining company will achieve the best performance. The geological complexity of some deposits requires adaptations of methods described in the literature to obtain more selectivity and reduce mining waste. There are some studies on geometry of underground structures, but a methodology that describes an adaptation of a room-and-pillar mining method for ore bodies with down-dip varying from 20° to 25° is novel. The present work aimed to reduce dilution by adapting the traditional room-and-pillar mining method (TRP) to inclined ore boLittle attention has been paid to the rehabilitation of derelict and ownerless mines in South Africa after their lifespan. This paper aims to explore management gaps in legislation that have resulted in the non-rehabilitation of derelict and ownerless mines in South Africa. There is growing evidence that supports the distressing effects of mining on people living around these mines in the North West Province. This paper was motivated by the current socio-economic status quo of old mining towns, the influx of illegal miners (Zama Zamas), severe environmental damages, and the violence associated with derelict mines. Underpinning this research was an ecosystem approach and integrated resources management principles, which formed the foundation for the decision-making process.The researcher used a mixed-method approach and employed convergent techniques. A semi-structured instrument was used to collect data from 200 respondents. The results indicated that there is a dire need for community-based consultative processes, and an absence of clear guidelines for derelict and ownerless mines to pressure mine management to adhere to rehabilitation standards. Moreover, the mining charter is ambiguous regarding policy implementation, budgetary allocation, and duration of the rehabilitation of these mines. The paper concluded that management challenges associated with derelict mines can be reduced if all stakeholders follow the guidelines as outlined in the environmental legislative framework (NEMA) of South Africa while being open to innovations in line with international best practices. It also contributes towards the development of guidelines for the management and implementation of legislation related to derelict and ownerless mines in South Africa from a philosophical, theoretical, and policy perspectivedies. This new method is entitled short-hole room-and-pillar (SHRP). The equations that measure the dilution are defined according to the geometry of stopes and openings. The results comprise comparative analyses of the operational and planned dilutions to measure the performance of the SHRP method. The average operating dilution of the SHRP method was more than five times lower than the planned dilution according to the TRP method. Low operational dilution indicates high selectivity of the method and its potential to reduce underground mining tailings.

Oct 9, 2024

By X Meng, W. A. Hustrulid, M. K. McCarter

Rock excavation in both surface and underground mining is largely accomplished using the drill and blast technique. At the perimeter of such excavations, cautious blasting procedures are often employed to minimize unwanted damage to the remaining rock. Of the several different techniques available, the use of explosive charges with a diameter smaller than the holes in which they are introduced (so-called decoupled charges) is the most common. In spite of the long and widespread use of the technique, a technically sound basis for relating the borehole wall pressure to the explosion pressure is still lacking. Such a relationship is required for optimal design

Jan 1, 2005

By S. Constantinides

Over the past 100 years we have witnessed a revolution in permanent magnetic materials. Prior to 1932 electrical machinery depended upon steels for both the soft and the permanent magnet structures. Because permanent magnet steels were easily demagnetized, motors, generators, loudspeakers and similar devices often used the interaction between two electromagnets. Motors and generators were mostly of the induction type, depending for function upon induced fields. The discovery of Alnico in 1931 and its rapid commercialization presaged an expansion of the industrial revolution and today, permanent magnet structures are widely utilized. [ ] DEVELOPMENT OF PERMANENT MAGNETS Act 1: Early Days of Permanent Magnets Alnico, which stands for aluminum, nickel and cobalt, is a family of alloys with similar structure and processing requirements. Additional elements, such as copper and titanium, are present in minor amounts to optimize magnetic properties. Alnico is known by many trade names around the world including Alcomax, Hycomax, Ticonal, Nipermag, Koerzit, Oerstit, Nialco, etc(1,2,3). In addition to the generic name ?alnico?, it is usually appended with a number representing the magnetic grade.

Jan 1, 2011

By SH. Shahsavari, H. Akbari, M. Noaparast, M. Oliazadeh

Mejel valley zircon ore in Iran is located in north part of Iran and was sampled to evaluate its concentration. The aim of this project was to define the mineralogy of this zone and separating zircon from other minerals using gravity concentrators and magnetic separators. It is constituted of various valuable minerals, mainly zirconium, niobium-tantalum, titanium, rare earth elements particularly cerium-bearing minerals namely zircon, sphene and rare earth elements oxides. We used statistical method for designing of experiments. Yates method used for analysis of basic experiments results. The grade of zircon in primary sample was 1.1%. Different experiments were designed to optimize all required parameters. The final concentration with 75% zircon was produced and final recovery was 79%. Finally, lab-scale based flow sheet was prepared using experiments results.

Jan 1, 2005

By Michael D. Justason

This paper details the static and Statnamic load testing on a 600 mm square pre-stressed concrete pile. The pile was located at Pier 15 on the 20 million-dollar Bayou Chico Bridge Project in Pensacola, Florida. The pile was 10.5 meters long and had a design load of 1.3 MN. Three static load test cycles were performed in November, 1996. The Statnamic load test was performed in January, 1997. The Davisson Failure load of the first cycle of the static test was 3.7 MN, and the Davisson Failure load of the Statnamic test was 3.2 MN. The load-displacement curves for the two types of tests were very similar, indicating that the Statnamic load test performed well in the sandy soils. Strain gauges embedded in the pile showed 35% skin friction and 65% end bearing for both test methods. Strain gauges were located at equal spacing at five elevations in the pile. A toe accelerometer verified the rigid body assumption of the Unloading Point Method currently used in the analysis of Statnamic load tests. The data collected from the pile instrumentation was of excellent quality and represents some of the best research to date comparing static and Statnamic load tests.

Jan 1, 1997

By Tim Q. Haldane

The ability to efficiently process lowgrade ores has allowed the Gold Fields Mesquite Mine in Imperial County, CA to expand from a 2.1 Mt/a (2.3 million stpy) rate in 1986 to its present 7.3 Mt/ a (8 million stpy) processing rate. Increased tonnage demands led to the 1989 construction and startup of a dump leach pad to supplement the existing heap leach operation. This resulted in an excellent opportunity to compare the two processes at the same operation. Additional operating costs associated with the crushed ore heaps are justified through enhanced recoveries, even at very low ore grades. Gold Fields' Mesquite Mine is a gold heap leach facility located about 55 km (35 miles) east of Brawley in southeastern California. Five open-pit mines will be developed over the projected life of the property, covering a total area extending to a maximum of 5.5 km (3.4 miles) to the east and west, and 2.4 kin (1.5 miles) to the north and south. Mesquite will process 7.3 Mt (8 million st) of ore and produce more than 6.2 t (200 000 oz) of gold in 1990.

Jan 1, 1990

By C. J. Badenhorst

Oxides of sulphur are corrosive and are produced when sulphur-containing fuels are burned. Sulphur dioxide (SO2) is a colourless gas with a characteristic, irritating, pungent odour. Exposure routes to the human body are mainly through inhalation and skin and/or eye contact. Symptoms of exposure to SO2 may include irritation of the eyes, nose, and throat; rhinorrhea (discharge of thin nasal mucous); choking; cough; and reflex bronchoconstriction. To protect employees against the ill health effects of SO2 exposure, they are often required to make use of respiratory protection whenever entering areas were the SO2 levels exceed the statutory limits. The use of respiratory protective equipment should always be a last resort and should be considered only after other control measures have failed to reduce occupational exposure levels to below the occupational exposure limit or whilst other control measures are being investigated or implemented. Whenever the use of respiratory protection equipment is considered, it should always be used as part of a comprehensive respiratory protection plan. It is also extremely important that all potentially exposed persons are adequately and comprehensively informed and trained.

Jan 1, 2007

By M. Zhang, M. Menabde, R. Middleton

Whilst mine planners almost universally assume deterministic forward commodity prices when undertaking valuations of mining projects, historical data well demonstrates that those prices are quite volatile. This paper seeks to understand and quantify how this forward price uncertainty will impact mining project valuation. This paper will also present a way of computing an upper bound on the expected Net Present Value (NPV) of a mining project given forward commodity price uncertainty.

Jan 1, 2007