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By R. Guardia, J. Hoskins, E. Claros, Y. Kamiya, R. Ramirez, J. Dalenz, P. Fernandez, E. Ilgren

Crocidolite is a well known causative agent for mesothelioma. Studies have shown that the pathogenicity of the fiber from different mines varies considerably and it has been postulated the parameter that appears most likely to account for this variation is fiber width. Epidemiological studies have shown that ‘thin’ fibers from mining areas of Western Australia and the Cape Province, in South Africa are associated with a high mesothelioma risk while exposure to ‘thick’ asbestiform amphibole fiber of the same fiber type are associated with little or no mesothelioma risk. This study is concerned with ‘thick’ Bolivian crocidolite but similar findings also probably explain the paucity of mesotheliomas in the Finnish anthophyllite, South African amosite and African Transvaal crocidolite mines. The findings from the present study suggest the incidence of mesothelioma in the three major cities of Bolivia is not significantly elevated above background even though Bolivian crocidolite has been used for the past 60 years commercially and residentially in all three cities. Although some cases of mesothelioma may have been missed due to a failure to reach hospital or a shortened natural lifespan, mesothelioma generally occurs after the age of 50, we cannot tell precisely the extent to which these were confounding. We suggest the most likely explanation for the lack of mesotheliomas despite the large populations at risk from the long and extensive residential and commercial use of crocidolite containing products, is related to an increased fiber width distribution and a concomitant reduction in the ‘Stanton fiber size’ fraction.

Jan 1, 2012

By R. L. Grayson

In 2010, MSHA began holding hearings on a new coal mine respirable dust rule, which proposes a 1.0 mg/m3 standard, a separate 0.1 mg/m3 quartz standard, and the use of single-shift samples for compliance. Small mines largely comprise the ?hot spots? where dust diseases of the lungs increased dramatically over the past decade. This paper presents findings on the feasibility of small mines? compliance with the proposed new 1.0 mg/m3 standard. It gives probabilities of noncompliance by MSHA district, seam height, and selected ?hot spot? counties. Because silicosis and respirable quartz dust appear to be the primary issues related to a recent doubling of the prevalence of dust diseases of the lungs, multiple regression models for prediction of the average total quartz content of compliance samples are given. These findings have significant implications on the need for better dust control methods.

Jan 1, 2012

The 30th annual American Mining Hall of Fame Awards Banquet and Fundraiser sponsored by the Mining Foundation of the Southwest (MFSW) will be held at the JW Marriott Star Pass Resort, Tucson, AZ on Saturday, Dec. 1, 2012. Each year, one living inductee, two recipients of Medals of Merit and up to five honorees from mining history are chosen by the MFSW for their outstanding contributions to the mining industry. Gregory H. Boyce will be the guest of honor, featured speaker and inductee into the American Mining Hall of Fame. Boyce, chairman and chief executive office of Peabody Energy, is being honored for his leadership in the coal industry.

Jan 1, 2012

By M. J. Gregory

The Pebble Cu-Au-Mo deposit in southwest Alaska is one of the world's largest porphyry deposits. The western part of the deposit was discovered by Cominco America in 1987, who sold the project to Northern Dynasty Minerals Ltd., in 2001. Northern Dynasty discovered the high-grade eastern part of the deposit in 2004 and went into a 50:50 partnership with Anglo American PLC in 2007, forming the Pebble Limited Partnership (Lang et al., 2008). The Pebble Limited Partnership has continued to delineate the deposit through diamond drilling with the most recent resource estimate released in February 2010 (Pebble Limited Partnership, 2010). The Pebble deposit mineral resources comprise 5.94 billion tonnes of measured and indicated resources grading 0.78% Cu EQ, containing 55 billion pounds of copper, 67 million ounces of gold and 3.3 billion pounds of molybdenum. Also delineated are 4.84 billion tonnes of inferred mineral resources grading 0.53% Cu EQ, containing 25.6 billion pounds of copper, 40.4 million ounces of gold and 2.3 billion pounds of molybdenum (Pebble Limited Partnership, 2010). Resources are calculated using a 0.3% Cu EQ cutoff. GEOLOGY AND MINERALIZATION Deposit Geology The Pebble deposit is located in the Kahiltna terrane, between terminal strands of the north-east-striking Lake Clarke strike-slip fault. This fault represents an accretionary boundary and separates the Kahiltna terrane to the north-west from the Peninsular terrane to the south-east (Lang et al., 2008). The Pebble deposit represents a large magmatic-hydrothermal system centered on a group of 90 million year old porphyritic hornblende granodiorite intrusions. An east-west cross section through the southern part of the deposit (Figure 1A) shows the typical relationships between the various rock units which host sulfide mineralization. Sub-parallel ~96 million year old granodiorite and diorite sills were intruded into siltstones of the Jura-Cretaceous Kahiltna flysch. In the west, these sills were cut by a ~96 million year old alkalic intrusive complex composed of porphyritic monzonites and monzodiorites and related intrusion breccias (Bouley et al, 1995). The mineralized 90 million year old hornblende granodiorite intrusions cut all rock types and comprise four small stocks in the western part of the deposit and a larger pluton in the eastern part of the deposit. Recent deep drilling indicates that these intrusions coalesce at depth. The strongest porphyry-style mineralization is centered on the eastern granodiorite pluton and extends into the surrounding rock units (Figure 1A). The western half of the deposit crops out at surface, whereas the eastern side is un-conformably overlain by a cover sequence of Late Cretaceous to Eocene sedimentary and volcanic strata. The deposit was tilted 20º to the east during the Eocene.

Jan 1, 2012

By M. H. Basiri

Crude oil, as a central commercial commodity, is tied to major economic activities in all nations. Also its price fluctuation plays a significant role in global political and economic situation, as a change in the price invariably affects the cost of other goods and services. Therefore reliable forecasts of the price of oil are interest for a wide range of applications. Several approaches have been proposed over the past few years. These may divide into three categories; artificial intelligent, statistical techniques and hybrid methods. The neuro-fuzzy is one of the sub divisions of hybrid method, containing neural network and fuzzy techniques. In this paper a novel forecasting model based on adaptive neuro-fuzzy inference (ANFIS) is proposed to predict monthly crude oil price. To be able to train and test the model, the statistical data from 1990 to 2010, was obtained from West Texas Intermediate oil prices. The results are compared with a multi criteria regression analysis, it is demonstrated that the neuro-fuzzy lead an accurate and more promising forecast.

Jan 1, 2012

An incremental-analysis-based stope design and cutoff grade calculation method was developed for an underground metal mine project. Traditional stope design methods are typically very time consuming and lack consistency and accuracy by manually drawing stope shapes. For quick reserve calculation and economic analysis, a new method named "3D incremental analysis based stope design" was created for mine-wide stope designs. The key idea of this method is to replace engineers' manual checking of each incremental ring with one calculation of all the rings, and to build the final stope shape with the maximum values. This process was realized through a 3D ring grid setup and proper naming conventions for rapid calculations. With this unique but practical method, multiple options for a mine design were completed within a short time before the final selection of optimal cutoff grade and best stope designs for the project.

Jan 1, 2012

By B. C. Vargas

The Toulon tunnel project is a key component of the Highway corridor on the French Riviera between Marseille and Nice and is a fundamental transportation infrastructure for the region. The first design studies started in the 1960?s. The tunnel project is made of 2 separate tunnels: South and North tunnel. The North tunnel was built between 1992 and 2002 after 10 years of difficult construction (for example, on March 15th, 1996, a collapse of the tunnel in the ?Marchand Area? generated a sink hole in the city Center, causing 20 months delay). The South tunnel alignment runs parallel to the North tunnel at the same depth below Toulon historical downtown (20 to 40m depth with some areas with less than 10m of cover). The Risk management program was studied to be a State of the Art program in urban tunneling construction. The Hydro Geological Context The whole project area is covered with backfills and colluviums of 1 to 4m thick. The Schist, marls and sandstones, randomly distributed along the alignment below the first layer have different characteristics. While the Schist are pretty compact, the marls are fractured. The other layers have very different characteristics, and many faults are located along the alignment, especially in the limestones. The Breccia are heavily decompressed and deformable, as well as the other soils located in the Marchand Area. This 80m long area is where the settlements need to be controlled with an extensive monitoring program. The complete Geological profile is presented in Figure 1. [ ]

Jan 1, 2012

By C. Wen

In Huoqiu region of Anhui Province, Fe2O3 occurs mainly in the form of specularite. Besides quartz, the gangue minerals include iron-bearing silicates such as chlorite and sericite which account for about 10% of the total gangue. The separation effect of conventional collectors is poor in the flotation of the minerals, that is, the average grade of iron concentrates is only 60-62%. Using the developed amphoteric collector can successfully realize not only the separation of specularite from various gangue minerals with results of iron concentrate grade above 65% and iron recovery of above 80% but also low temperature flotation at 15°C.

Jan 1, 2012

By P. D?Elia

Following a study by NIOSH on the availability of teams in the U.S. as well as existing training sites and their capabilities, the Penn State University, leaders of the Pittsburgh Section of SME, providers of mine rescue equipment, and industry sponsors united to establish and make fully functional a student mine rescue team at Penn State University. With the growth of MERD and mine rescue competitive events at Missouri S&T, the Mine Training and Technology Center in PA, and at Colorado School of Mines Edgar Mine, a critical mass of effective training venues were made available to help student teams progress and develop mine rescue skills. The challenges to be met in creating and developing a student mine rescue team will be discussed. The rewards from this type of effort will be the quick capability of graduates from mining engineering programs to be involved in not only mining operations, but industry mine rescue teams and other leadership roles as well.

Jan 1, 2012

By H. Kinilakodi

The authors previously developed a methodology that combines injury and citation measures into an overall mine safety performance evaluation tool, called the safe performance index (SPI). It can be easily adopted by mine operators to monitor trends in their injury and citation experiences as a risk assessment method. In this paper, six normalized safety measures and the SPI are used to evaluate the health and safety risk that existed at mines in the two years preceding the occurrence of a fatality. The percentage of mines is given for which the risk was high or where trends of some of the safety measures indicated moderate risk. In 50% of the mines, this mine safety performance tracking method could have been helpful to the companies, state agency or the U.S. Mine Safety and Health Administration (MSHA) in recognizing and addressing emerging problems with actions that may have been able to predict high-risk conditions, the fatality and/or other serious injuries. The approach would have given extra scrutiny to the risk for mines that encompassed 74% of the fatalities during 2007-2010.

Jan 1, 2012

By Michael Wortley

Metso?s Process Technology and Innovation group is a world leader in mineral processing consulting. A significant amount of this consulting work involves process integration and optimization (PIO) studies, which include investigating the effects of drill-and-blast design and implementation on downstream processing. Critical to these studies is the ability to track specific ore into, and through, the plant. To increase the accuracy of this ore tracking, Metso Process Technology and Innovation (PTI) developed a system to track ore using a radio frequency identification (RFID) transponders technology designed to allow tracking of ore from its source through blasting, run-of-mine (ROM) pads, crushers, intermediate stockpiles and, finally, into the concentrator. The system is called SmartTag. Since its commercialization in 2007, SmartTag has been used in the majority of PTI?s consulting projects, and several permanent systems have been installed worldwide.

Jan 1, 2012

By John Hickey

Management teams at mining companies begin to ask themselves whether to take a company public and, if so, how to do it as they approach the normal threshold for going public in terms of revenue and operating performance. Today, the expense of going public generally suggests the company has at least $20 million in annual revenue and at least $2 million in cash. The revenue number can be lower for mining companies with large reserves. In order to properly attract the investing public, the company must also be operationally strong with robust prospects. The company should have a strong management team and a consistent history of double-digit growth that will continue into the foreseeable future. Assuming the thresholds are met, a company?s management needs to weigh the pros and cons of going public.

Jan 1, 2012

Column flotation has been successfully implemented on a production scale in the Athabasca oil sands. In this application, bitumen is recovered and mineral matter is simultaneously rejected from a middling stream originating from a primary separation vessel. Exploiting the natural hydrophobicity of bitumen, the middlings streams have traditionally been processed utilizing conventional, mechanical flotation cells. Although these cells offer adequate bitumen recovery and mineral rejection rates, operating costs are high due to the required maintenance of the wetted mechanical components. In comparison, column flotation provides superior metallurgical performance while offering a lower maintenance demand. Both metallurgical and mechanical characteristics of column flotation are discussed to demonstrate the benefits of this technology for the recovery of bitumen from oil sands.

Jan 1, 2012

By B. Caro Vargas

The Toulon Tunnel project is a key component of the highway corridor on the French Riviera between Marseille and Nice and is a fundamental transportation infrastructure for the region. The first design studies started in the 1960s. The tunnel project is comprised of two separate tunnels: south and north. The north tunnel was built between 1992 and 2002 after 10 years of difficult construction. On March 15, 1996, for example, a collapse of the tunnel in the Marchand area generated a sinkhole in the city center, causing a 20-month delay. The south tunnel alignment runs parallel to the north tunnel below Toulon?s historical downtown at a depth of 20 to 40 m (65 to 131 ft) with some areas with less than 10 m (32 ft) of cover. The risk management program was studied to be a state of the art program in urban tunneling construction.

Jan 1, 2012

By M. Z. A. Bakar

A series of full scale laboratory linear rock cutting tests was carried out with a long bladed single disc cutter (292 mm diameter, 11mm wide constant cross-section blade) on dry and water saturated sandstone blocks using a linear rock cutting machine (LRCM). The muck collected from the cutting tests has been analyzed to establish a link with the specific energy (SE) of the operation. Coarseness index (CI), a non dimensional parameter, has been found to be a useful indicator of the relative efficiency of the cutting operation. An inverse relationship of the form SE = k CI-n is observed between SE and CI with very high CI usually corresponding with the lowest values of SE. The power n of the relationship for both dry and saturated rock tests is much less than the values found in the previous studies using constant cross section disc cutters and is believed to be dependent on the strength of the rock and the cutter type used. Although the average CI is found to be lower for saturated rock than for dry rock, at the same time saturated rock cutting is found to be less energy intensive (in terms of SE) than dry rock cutting. Moderate correlation exists between the production rate or yield and the SE of the cutting operation for both dry and saturated rock, which can provide some useful information about the field production rate discounting the effect of discontinuities in the rock mass.

Jan 1, 2012

Multilevel-multiseam hardcoal mines on the European continent usually consist of a huge network of underground openings, sometimes more than 200 km long in total, with some longwalls operating down to a depth of 1,500 m. While operating several longwalls simultaneously, these mines are making use of a number of stationary and mobile measurement- and analysis units in their main ventilation passes combined with atmospheric measurements on the surface. This paper provides an overview over the systems and technology used and describes the typical set-up of a measuring net. To detect and monitor underground fires through fire gases measurement and -analysis, a mobile underground testing laboratory collects data locally in the area of the fire. These laboratories have proven to be extremely useful not only during the actual fire fighting but also for the long-term gas measurements in critical mine areas. They have repeatedly detected starting fires and have thus given the mine the opportunity to react early and to avoid larger damage. Therefore several mobile laboratory units have now been installed for long-term testing in a number of German mines and similar units are being used in the Czech Republic and Poland.

Jan 1, 2012

By M. M. Poulton

Universities are not immune from the large number of retirements facing the mining industry. Department heads anticipate that we will need to replace all of the senior mining engineering faculty in the U.S. by 2020. Long term studies of Ph.D. completion times and success rates indicate that in Engineering disciplines in the U.S., the ten year completion rate is 65% at best and the four year completion rate is less than 8%. We do not have accurate data on completion rates and times for mining or metallurgical engineering Ph.D. students in the U.S. but students self-report their expected completion times are around 4 years. National data on doctoral students indicate that younger, full time students with sufficient financial support have a higher probability of success in completing their degrees in a timely manner. Students in Eastern U.S. mining engineering programs are on average 32 years old, 85% are full time, and the gap between support and cost of attendance is $5,000 per year. Students in Western U.S. programs are on average 38 years old, 78% are full time, and the financial gap is $8,483. Further, it appears that domestic graduate students are not very geographically mobile. The current demand for new faculty is higher in Western programs but the longer term retirements are higher in Eastern programs. While all Ph.D. students who responded to the 2010 survey indicated an interest in a faculty position at some point in their careers, very few were applying for the open positions. Over the past 35 years for which data could be obtained, the maximum number of Ph.D. students enrolled in mining engineering in the U.S. is 115 with a maximum of 27 degrees granted in one year. On average 89 students are enrolled in doctoral programs in mining engineering in the U.S. with average degree production of 15 Ph.D.s per year.

Jan 1, 2012

By W. Burger

In underground mines worldwide, a large number of short and small diameter slot holes need to be excavated. Herrenknecht has developed and built a new boxholeboring machine based on the well-proven Microtunnellingpipe jacking technology. The innovative Boxhole Boring Machine significantly increases work safety and requires only minimal drift dimensions. The high and consistent production rates that can be achieved result in enormous time savings compared to conventional drill and blast excavations. GENERAL ASPECTS In gold, copper and ore mines ventilation shafts are required to prepare block caving operations, to discharge ore onto the transportation level and to provide evacuation shafts. A high level of occupational safety and efficiency is the main objective when drilling vertical or inclined shafts. The faster and more safely shafts can be constructed, the earlier the actual production in the mine can start or be continued. Mechanized or conventional methods (drill&blast) that have been used to date only partially meet the required safety standards and fail to provide the requested production rates.

Jan 1, 2012

By Andrew Hall

Many Latin American countries are facing a scarcity of water. As such, infrastructure decisions are quite different from those made in parts of the world that experience a positive water balance. In the latter case, the water treatment approach tends to be ?treat and discharge.? For Latin American regions facing the challenges that go with a negative water balance, the focus is on resource optimization and reuse. Historically, the water challenge has had a significant impact on economic development in Latin America, especially in sectors such as mining, where water usage is high. At the same time, countries such as Chile and Brazil are major development targets for mining and oil and gas operations. Given the water supply challenge, industry is increasingly turning to technologies and processes that maximize water recovery and reuse. With sulfide precipitation and ion exchange water treatment processes for example, it is possible to treat and recover more than 99 percent of water for reuse onsite. These technologies have been applied successfully in other regions of the world where water conservation practices are essential to economic survival.

Jan 1, 2012

By M. Z. A. Bakar

To investigate the differences in the radial drag pick cutting performance in dry and saturated sandstone, a suite of linear rock cutting test was performed using linear rock cutting machine (LRCM). Experimental results of 50 data passes, incorporating 350 data cuts were used to compute cutting, normal and side forces required for determination of other performance related parameters. Although the forces required to cut the dry and saturated rock were in congruence for most of the spacing and depths of cut combinations; but the overall averaged cutting and normal forces for saturated rock cutting were found to be 9.9% and 9.4% respectively higher than the dry rock cutting. The increase in the overall averaged forces was attributed to strength variability of one of the saturated block affecting the overall forces. The side forces experienced a negligible drop in saturated rock cutting. An increase of 28% and 9% in the actual and nominal specific energy values respectively was also recorded when cutting saturated rock as compared to the dry rock cutting. The increase in saturated rock specific energy is attributed to production of large amount of fines and few large sized chips directly contributing towards increase in specific energy. The optimum s/d ratio for dry rock tests was found to lie between 6 and 8 whereas for saturated rock cuts this value lied between 5 and 9.

Jan 1, 2012