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Jan 1, 1969

By P. -É. Boileau, M. Smets, T. Eger, J. Boutin

Long-haul dump (LHD) vehicles used in underground mining are known to expose workers to important levels of whole-body vibration1. These vehicles are generally designed without suspension and may be categorized as small or large LHDs depending on whether their respective load capacities are lower or larger than 3.5 cubic yards. While the majority of older vehicles are equipped with a rigid or unsuspended seat, more recent LHDs often incorporate a suspension seat. The objective of this study was to define the vibration spectral characteristics of most commonly encountered large and small LHD vehicles operating in mining operations. This was done in an effort to categorize the vehicles in terms of vibration spectral classes to be reproduced on a laboratory whole-body vibration simulator to assess the vibration attenuation performance of a typical LHD suspension seat. Methods Vertical vibration measured at the seat attachment point of 8 small and 8 large LHD vehicles operating underground in typical mining operations under loaded and unloaded conditions was considered as the basis for defining the spectral classes. By regrouping the data collected for each LHD vehicle size and load condition, the overall distribution of acceleration power spectral density (PSD) of measured floor vibration was determined over the 0.5 to 20 Hz frequency range. Mean and envelopes of maximum and minimum values of PSD spectra were computed to define the spectral classes, along with the corresponding values of frequency weighted rms acceleration determined in accordance to the ISO 2631-1 standard2. These spectra were further used to calculate the displacements needed to drive a whole-body vibration simulator consisting of a platform supported by two servo-hydraulic actuators having a total stroke of ±100 mm. For validation purposes, the vibration acceleration spectra measured on the simulator were compared with the target spectra representing the spectral classes. Finally, the vibration transmissibility characteristics of a typical suspension seat were determined under sine sweep excitation using both a rigid mass load and a human subject having a mass of 62 kg and 85 kg, respectively. The SEAT value, representing the ratio of seat to base frequency-weighted rms acceleration, was further measured under each of the defined LHD vibration spectral classes by loading the seat with an 85 kg subject. Tests were repeated three times and the mean SEAT values were determined to assess the seat’s ability to reduce exposure to whole-body vibration in LHD vehicles. Results Three spectral classes applicable to both loaded and unloaded conditions were defined as shown in Figure 1: one for large and two for small LHDs. The influence of load on frequency-weighted rms acceleration was found to be negligible for large and Class I small LHDs, while a shift of the peak acceleration PSD to lower frequencies was noted for the loaded vehicles. The influence of load was found to be more important for Class II small LHDs. Table 1 provides a

Jan 6, 2006

Phosphorus Phase Analysis of Medium-Low-Grade Rare-Earths-Bearing Phosphate Ores

Sep 13, 2010

By R. Tyreman, G. Ritson

"The Red Lake Mine is situated in Balmer Township, Red Lake area in northwestern Ontario. It is an underground mine that has been in production since 1948. The property was originally known as the Dickensen Mine and was shut down in 1996.A feasibility study was carried out in 1998 and it was determined that a new mill should be constructed with a throughput rate of 600 stpd. The life-of-mine average gold grade was projected to be 1.35 oz/t with gold predominantly associated with arsenopyrite and pyrite. Metallurgical testwork indicated that the optimal flowsheet for gold recovery would include an autoclave for oxidation with a carbon circuit for adsorption. To limit capital cost and establish cashflow, the mill was constructed without an autoclave. The recovery by gravity and cyanidation was projected to be 83%. A flotation plant was constructed at the tail end of the circuit to recover the additional gold associated with sulphides from the leach circuit tailings. This material is being stockpiled onsite for future oxidation treatment.Detailed engineering was started in early 1999 and the first gold was poured in August 2000. One feature of the project was the use of Contact Lake equipment from Cameco’s Contact Lake project. The entire mill was purchased and equipment re-used where possible. The capital cost for the process facilities was C$3 1.5 million."

Jan 1, 2001

By Drew Floyd

Five full-scale pile load tests were performed on pairs of PZ-22 sheet piles installed with a vibratory pile driving hammer. The sheet piling was installed in several locations in soil generally consisting of miscellaneous granular fills overlying soft organic silts, inorganic silt interbedded with sands and gravels, very dense glacial till and shale bedrock. The test program also included the use of tip tell tales to determine what capacity could be attributed to tip resistance and skin friction. During the design phase of the project, it was assumed that the capacity of the sheet piles driven with the vibratory hammer could be correlated with the rate of penetration. The correlation between vertical capacity and rate of penetration would be used as a basis for determination of a driving criteria from driving the production sheet piling. The sheet piling load tests demonstrated that it was not possible to correlate the capacity of sheet piling driven with a vibratory hammer and the rate of penetration. It was also demonstrated that the capacity of the sheet piles was directly related to the density of the soil at or just below the tip. The results also tend to agree with empirical equations provided by Meyerhof (1976).

Jan 1, 1989

By Catherine N. Mulligan

Thickening of mine tailings is a relatively new concept for their sustainable management. Removal of water from the tailings to form a paste instead of slurry disposal decreases environmental and geotechnical concerns. As the use of these pastes is relatively new, their behaviour requires investigations such as liquefaction and seismic stability, freeze-thaw behaviour, consolidation and leachate characterization. Slurry density, ore type, particle size distribution, specific gravity and environmental conditions can all influence paste characteristics. In this paper, the effect of the above-mentioned parameters is examined. New developments in water removal, and additives (such as flocculating agents, cements, organics, fertilizers, etc) leading to low moisture content tailings are reviewed, and the potential for thickening to enable sustainable management of mine tailings is discussed with respect to storage volume requirement, use of virgin land, consolidation of the tailings, land use after decommissioning.

May 1, 2007

The compliance sampling method for coal mine dust in the United States has not changed appreciably in the last 30 years. A call for more frequent sampling with immediately available results is leading to new instruments that may supplement or replace the existing sampler. This report discusses two such instruments that provide immediate results of dust levels. The first, called the Respirable Dust Dosimeter (RDD), is designed to supplement the existing U. S. cyclone compliance sampling method. It uses the pressure drop across a filter to provide an inexpensive screening type of measurement. The RDD has been tested in the laboratory and a limited number of coal mines. Side by side testing has compared the RDD performance with personal coal mine samplers in triplicate area sample measurements. Results show that the differential pressure of specific filtration media can be an effective surrogate for respirable mass. Data show that there is a dependence on coal type and an effect of relative humidity. There also appear to be two distinct responses related to coal type. For specific coals the coefficients of determination, R2, are better than 0.9. For general use the detector tube, using laboratory generated calibration curves, can be used to estimate respirable dust levels. However, a calibration to a specific coal type may substantially improve the accuracy. Another sampler in development is called the Personal Dust Monitor (PDM). Designed to give compliance quality accuracy, the PDM uses the frequency change of a vibrating element to measure dust and give immediate feedback of results. Results of laboratory comparison of the prototype PDM sampler to personal gravimetric samplers indicate R2 values of better than 0.99 for three different coal types. Work is in progress to package the components into a person-wearable unit combined with a cap lamp system with a total projected weight of less than 1.4 kg (3 lbs).

By J. M. Somers

Methane is a powerful greenhouse gas and the principal component of natural gas. Coal seams often contain significant quantities of methane, and underground coal mines must ensure that methane released into the mine during coal extraction does not build to dangerous levels. This is accomplished in part through the use of large-volume ventilation systems that remove methane from the mine and release it to the atmosphere. Although the methane concentration exhausted is quite low (typically <1 percent), the volume of air that ventilation systems move is so great that they actually constitute the largest source of methane emissions from underground coal mines. Each year underground coal mines throughout the world emit more than 500 billion cubic feet of methane from their ventilation systems. An air pollution control technology, thermal oxidation using a flow-reversal reactor (TFRR), has emerged as a potential solution to ventilation air methane (VAM) emission mitigation. One manufacturer of TFRRs has demonstrated its oxidizer design (the VOCSIDIZER?) at coal mines in the United Kingdom and Australia. These demonstrations tested the technology?s effectiveness at oxidizing low-concentration methane, as well as its ability to tap the excess heat to produce steam for electric power generation. In early 2007, the first U.S. demonstration of this technology began operation at an abandoned mine in West Virginia. The project is designed to prove the technology?s operational robustness, its ability to reliably oxidize methane at concentrations typical of mine exhausts, and its safety. If the technology is employed at active underground coal mines, it offers the potential to mitigate substantial quantities of global methane emissions. This paper discusses global VAM emissions, options for the recovery and utilization of VAM, and existing projects such as WestVAMP in Australia and the ongoing U.S. VAM demonstration project.

Jan 1, 2009

By J Ross

The foundation of effective leadership is communication. You can have all the leadership theories, models and training you want, but in the end it is all about leaders talking to, listening to and understanding the point of view of those below and above them.The foundation of effective safety is peoples’ behaviours. Every incident, every near miss and every safe act comes down to what one person does and how that affects themselves and others. We tend to focus these behavioural considerations on the people at the ‘coal face’, those most in harm’s way. But it is the individual behaviours of everyone in the organisation, particularly those at the top, which are just as (if not more) important. The foundation of effective safety leadership in the mining industry is that it starts at the top, with the individual behaviours of leaders. The behaviours of each and every leader will be reflected in their teams. And where their teams are made up of leaders, these leaders will pass these behaviours on to their teams and so on. It’s the sum total of what people see their leaders do and what they do as a result, that creates the ‘culture’ of the business – and it’s this culture that makes or breaks how safely people work.

Mar 21, 2011

Your thoughts on the current status of the global minerals industries? The global economic, technological, social and political changes of the last two decades of the 20th century resulted in the emergence of a restructured minerals industry. This industry is now based on a new cost-cutting philosophy; utilization of modern technology; productivity gains rather than production tonnages; diversification of mineral markets; and globalization of exploration, mining and processing. Quantity and tons used to be the focus. The emphasis today is on remaining competitive in the marketplace by lowering per-unit production costs as much as possible. What factors and trends will impact the minerals industries in this, the 21st century? A number of parameters will impact minerals operations and shape the future sustainability and growth of the minerals industries. Increased demand for minerals will be accompanied by the demand for technical advancements. We will also see a continued emphasis on health and safety, environmental stewardship, and education and training. Let me elaborate.

Jan 1, 2002

Incorrect sampling and measurement operations and misunderstanding the components of variability can cause huge economic losses to the mining industry. The main objective of this paper is to illustrate by means of four historical facts how Codelco has been evolving in those issues since the late 1980s. The El Abra bias, the awareness of the different kind of sampling errors and the role of Francis Pitard, the awareness of weighting errors, and the understanding of the components of nature and process variability are described. It has been a slow but a consistent process. Much progress has been achieved but still there are many opportunities for improvement to transit from the tonnage culture to the productivity culture.

Jan 1, 2008

By M. L. Bakker

Keywords: Pyrometallurgy, top submerged lance (TSL), nickel, PGM, calcium ferrite, lime ferrite The ISASMELT? top submerged lance (TSL) bath smelting process was developed in Mount Isa, Australia by Mount Isa Mines Limited (now a subsidiary of Xstrata plc) during the 1980s. By the end of 2011, the total installed capacity of the ISASMELT? technology will exceed 9 000 000 metric tons per year of feed materials in copper and lead smelters around the world. Commercial plants, operating in Belgium and Germany, are also batch converting copper materials in ISASMELT? furnaces. This TSL technology is equally effective for continuous converting processes, whereupon it is called ISACONVERT?. This paper presents the recently patented ISACONVERT? process for the continuous converting of nickel and Platinum Group Metal (PGM) containing mattes using the calcium ferrite slag system. The paper focuses on the potential application of the ISACONVERT? technology to existing nickel and PGM smelting complexes.

Jan 1, 2011

By Richard L. Rains

The Bureau of Mines made a study of mines and prospects of the Benton Range RARE II area (No. 5056), Mono County, California in October and November 1980. The study area is west of Owens Valley and 30 mi (40 km) north of Bishop, California. The mineral deposits were evaluated by examination of mines, prospects, and mining claims by the Bureau of Mines. Geological, geochemical, and geophysical studies were conducted by the Geological Survey. The principal mineral commodities of the Benton Range RARE II area are gold and silver but tungsten deposits may also extend into the area. Properties with resources are listed in table 1; their locations are shown on figure 1.

Jan 1, 1982

By M. V. Mielke, R. E. Hagen, R. L. Bennett

FINE IRON ORES, and concentrates such as those produced from taconite, must be converted to lump form by some process of agglomeration before they can be used effectively in the blast furnace or open hearth. At the present time, four major processes for agglomerating these materials are being used on a commercial scale: sintering, nodulizing, pelletizing and briquetting. IN 1945 U. S. Steel Corp. through its subsidiary the Oliver Iron Mining Div., drew up tentative plans for an agglomerating plant on the Mesabi Range which would include a nodulizing kiln and a sintering machine. The purpose of the plant was two- fold: during its initial operation it would provide data on agglomeration of high grade ore fines, and would help relieve the shortage of ore for open hearth charging. Subsequently, it would be available for agglomerating taconite concentrates. While operating on fines screened from direct ore, it was planned to develop techniques and personnel so that a workable plant would be ready to handle taconite concentrates when the time came.

Jan 1, 1954

By William R. Yernberg

The combined 78th Annual Minnesota Section of SME Meeting and 66th Annual University of Minnesota Mining Symposium was held April 19 and 20, 2005, in Duluth, MN. More than 300 mining professionals, including engineers, executives, mining managers and suppliers, from throughout the United States and eastern Canada attended the meeting. This year’s theme was “Global Demand: A Window of Opportunity.” The meeting included a keynote address, technical presentations and a trade show. The atmosphere at this year’s meeting was upbeat. The iron ore mining industry in Minnesota is experiencing one of its biggest turnarounds in history. Because of greater demand, iron ore prices increased 20 percent during 2004 and 71.5 percent so far in 2005.

Jan 1, 2005

By Tracy Brettmann

The use of rock-socketed Augered Cast-In-Place (ACIP) piles is new to the Austin and central Texas region. This case history describes the design methodology, load test results, quality control procedures and the rate of production pile installation for the first large commercial project where ACIP piles were used in Austin. The piles were 24 inches in diameter and extended through about 45 ft of alluvial materials to be socketed 6 ft into limestone. A full-scale instrumented load test was performed on a test pile that was loaded to 452 tons and held for 24 hours. Telltales were installed in the middle and the tip of the test pile. As part of the overall quality control procedures, singlehole sonic integrity logging was performed on the production piles to verify structural integrity during pile installation. During pile production, an average of 14 piles per day were installed, which is approximately seven times faster than the original design that consisted of drilled shaft foundations.

Jan 1, 1998

By C. H. Johnson

This paper on the out-and-fill method of mining is one of a series on mining methods published by the United States Bureau of Mines. It has been compiled chiefly from recent publications of the bureau describing in detail mining methods and costs at various mines. Other sources of information were the technical press, the Transactions of the American Institute of Mining and Metallurgical Engineers, the Mines Haudbook, and company reports. References other than those mentioned in Table 1, which lists the mines entering into this discussion and gives general data regarding them, are given in the body of the paper. The authors wish to acknowledge the kind assistance of many operating officials, either through correspondence or in the course of numerous visits to their mines. DEFINITION OF CUT-AND-FILL STOPING The out-and-fill method of stoping is that method in which relatively small sections or slices are taken successively from the lower surface of a block of ground by open-stoping methods, the broken ore being removed and each section filled with waste material before the next is mined. This definition excludes shrinkage stoping, even with subsequent filling; it excludes square-set and fill methods; it excludes the Mitchell slice method, which may be classed as underhand square-setting; it excludes the systematic use of stull sets and filling, which is a variation of square-setting; it excludes any method involving the caving of the ore, walls, or overburden during the process of extraction, although caving may be allowed to take place when the waste fill is withdrawn for use in other stopes; and it excludes any open-stope method without filling. Through variations, which will be discussed later, the cut-and-fill method merges into shrinkage stoping, open stoping, or square-setting. The use of casual timber support, such as props, stulls, or timber cribs for holding up weak portions of the back does not constitute a change from cut-and-fill to square-set mining.

Jan 1, 1933

By V. Blet

Rare earth elements (REE) are regarded today as highly critical raw materials but currently lack suitable recycling processes. A combined hydro- and pyrometallurgical process aimed at REE recovery from used NdFeB permanent magnets was recently developed by the CEA. The process integrates the physico-chemical treatment of magnets, followed by a solvent extraction step for the recovery and intra-REE separation using a selective extractant. A subsequent pyrometallurgical treatment via molten chloride salt electrolysis allowed the isolation of pure Dy metal. Technical-economic assessment and life-cycle analysis were also conducted. Following this first successful demonstration, a new project aimed at the recovery of REE from end-of-life nickel-metal-hydride batteries is currently being developed in association with industrial and academic partners. The project aims at evaluating from an experimental and economic perspective different processes converging at the production of value-added products such as cermet materials for catalytic applications, purified REO concentrates, or metallic alloys.

By S. W. Stogran

"A brief summary of the environmental testing and analyses required to ensure and maintain compliance of mining properties will be discussed. Programs for new and existing properties and for properties which may be purchased will be outlined and potential solutions to problems will be discussed. In addition to the compliance aspects of operations, due diligence will be discussed.1.0 INTRODUCTIONThe impact of mining projects on the environment is an area of major concern to the public, governmental agencies and mining companies. Due to the ever increasing pressure on the government by special interest groups and the public, governments have implemented legislation to control potential environmental impact of mining, from the exploration phase through to close-out. By not planning for environmental issues during all phases of a mining operation, unavoidable delays and retrofitted environmental programmes will be expensive and cause projects to be delayed, which, ultimately, may cause the abandonment of a mining prospect. Most jurisdictions require at least one full year of background environmental data. Therefore, many thousands of dollars are wasted as construction is interfered with or held up due to data collection. This may be avoided by a thousand dollars worth of sample being collected and analyzed early in the project."

Jan 1, 1992

By Don W. Deere

Faults under high rock cover represent some of the most severe ground conditions a Tunneler can encounter. High ground water pressures and flows are usually associated with mountain faults. Ground behavior can range from blocky ground to flowing sands and squeezing clays. Sticking a IBM within a fault zone for many weeks, with the disastrous financial consequences, is still a common occurrence. Interpreting the geology and detecting the location of a fault prior to penetrating it is a fundamental step to successful tunneling. Ground water control through predraining or pre-grouting is the second fundamental step. This paper discusses techniques applied for detecting and crossing mountainous fault zones through the use of case histories across the globe.

Jan 1, 2007