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By Oliver Zach

To know as much as possible about the condition of the refractory material (lining thickness, slag layer, build ups, ...) in an high temperature furnace is very important due to the safety and economic impacts. The new CONSCAN system offers the possibility to measure the inner surface of an furnace, and based on this results to calculate the thickness of the refractory lining, slag layer, build ups,.... The CONSCAN System provides this results as figures and graphics. This system is also working under hot conditions so it is not necessary to cool down the furnace. Based on these results the process control and the refractory lining concept could be optimized for maximum campaign life of the furnace.

Jan 1, 2006

By Vincent Tirolo

Two separate secant pile cofferdams were constructed as part of an extensive rehabilitation and modernization of the New York City Transit's Lexington Avenue/Third Avenue IND Station at 53rd Street in Manhattan. Major high rise structures and outpatient hospital facilities bordered the site. The roadway is an important east-west corridor in mid-Manhattan. In order to perform the construction of new escalator and elevator shafts over 250 linear feet of secant wall was installed to the top of rock or to the existing subway roof. Much of the secant wall was constructed from below a temporary roadway decking system using a low headroom rig. The roadway decking system was supported on shallow spread footings. The secant piles were drilled using crawler mounted hydraulic rotary drill rigs. The secant wall provided a watertight, rigid cofferdam that minimized settlement and other disruptions to existing structures and utilities. During later stages of the project the secant wall also supported the roadway decking system.

Jan 1, 2003

By C. Pelley, S. Kelebek, T. Katsabanis, B. Nanthakumar

"As part of a larger investigation on generation of fines from mining activities and their effect on downstream operations, ore samples from Onaping area stockpiles of Falconbridge Ltd were studied. Batch flotation tests were conducted on the stockpile samples and fresh ore samples to explore the effect of stockpiling on grade-recovery performance. Head grade and particle size distribution of the samples from stockpiles were adjusted so that the samples compared are similar to each other. In additional tests, fresh ore samples were blended with stockpile samples at various percentages, representing 27.4, 50.2 and 81.5% of stockpile samples.The samples from stockpiles produced inferior nickel grade-recovery curves compared to fresh ore. The poorer grade-recovery performance was attributable to two factors. First, a significant dilution effect was observed due to the nearly complete flotation of pyrrhotite. Secondly, while pyrrhotite from stockpiled ore became highly floatable, the same stockpiling conditions caused nickel losses that were attributable to non-floatability of some pentlandite.In the case of blending, there was generally insignificant difference in the nickel grade-recovery between fresh and blended samples when the blending cases involved 27.4 and 50.2% stockpile samples. However, an increase in pyrrhotite recovery was observed for both blending cases. At 81.5% blending case, degraded grade-recovery was significant primarily due to the nearly complete flotation of pyrrhotite. There was a small, but noticeable amount of nickel loss for this case. However, for lower ratios of blending this loss was negligible.The increase in pyrrhotite recovery was partly attributed to its activation by Cu and Ni ions. Formation of a significant amount of elemental sulphur was also apparent from analysis of stockpiled samples. It can be concluded that pyrrhotite is mildly oxidized under stockpiling conditions while part of the pentlandite undergoes a more severe oxidation."

Jan 1, 2006

By Mark Sanders

This report compares a proposed 10/60 "piggyback" 02 generating self-rescue unit to the standard CO self-rescue unit with respect to work task interference. A simulated low seam coal mine was constructed and subjects performed locomotion, shoveling, cart pushing, and timbering tasks with the 10/60 or self-rescuer attached to their belts. Task completion time was longer on all tasks when wearing the 10/60 unit, although only locomotion was statistically significant. The 10/60 unit was bumped over 100% more often than the standard self-rescuer. Implications for design of the proposed 10/60 container are: 1) unit?s container must be extra durable to withstand the added abuse it is likely to receive by low coal miners; and 2) extra consideration must be given to preventing the device from slipping on the belt while working, especially in low coal.

Jan 1, 1980

By E. G. King

The literature contains little thermodynamic information regarding inter-oxidic compounds of the ferroalloy elements and, as a result, thermodynamic considerations of extractive and utilization processes involving these elements have been hampered. As part of a Bureau of Mines program to improve this situation, this paper reports the heats of formation of three calcium vanadates and two magnesium vanadates. There were no previous similar data for any of these compounds. The experimental method was hydrochloric acid solution calorimetry, using calorimetric reaction schemes involving the vanadates and their component oxides. The results were expressed as heats of formation from the component oxides and from the elements. Corresponding free energy of formation values were calculated. The data show that the calcium and magnesium vanadates are stable with respect to all possible decompositions in which vanadium remains pentavalent. This conclusion is similar to the one drawn by Koehler6 for three sodium vanadates.

Jan 1, 1962

By Joseph N. Bakambu

It is currently recognized by mining society that autonomously guided underground mining vehicles may greatly increase the efficiency of mining production and improve human safety. Recent results in mobile robotics, data fusion and sensor development provide a solid basis for solving the problems related to autonomous underground navigation. Recently developed commercial systems mostly rely on the infrastructure that is expensive and difficult to maintain. Guideless navigation in unstructured and harsh environment of underground mines is still a challenging task. In this paper, we describe an autonomous navigation system for an underground mining vehicle equipped with on-board dead reckoning, inertial and optical sensors. This system does not require any artificial infrastructure and is capable to guide the vehicle along the complex environment of interconnected underground drifts; it also ensures the detection of obstacles on the vehicle path. The user interface for monitoring and control is described and the results of laboratory tests and on-site experiments are presented. Work in progress addresses the system integration for real equipment, and the system upgrade, adding map-building and selflocalization capabilities .

May 1, 2002

By P. Tittes, M. Deal, M. Spicher, S. McDaniel, J. Wickens

"Haile Gold Mine is located near Kershaw, South Carolina, approximately 50 miles south of Charlotte, North Carolina. Gold was first discovered at the site in 1827, and the property has been through several operating periods since. The relatively low grade and refractory nature of the deposit has been a challenge for efficient processing since the start of mining on the property. Early processing techniques included gravity separation and barrel chlorination. The last operation employed heap leaching in 1985 through 1992. After being closed and reclaimed for over 20 years, the property is poised to re-open and produce once again. In this chapter of the Mine’s legacy, flotation and ultra-fine grinding will be employed to achieve economic extraction of gold and silver from the pyrite. This paper briefly reviews some of the mine’s history, the metallurgical testing, the flowsheet and discusses design considerations.INTRODUCTIONHaile Gold Mine is located near Kershaw, South Carolina, approximately 50 miles south of Charlotte, North Carolina. Gold was first discovered at the site in 1827, and the property has been through several operating periods since. The last operation employed heap leaching in 1985 through 1992. Since then, the property has been closed and fully reclaimed. Romarco Minerals acquired the property in 2007, and began an exploration program that has delineated over 62 tonnes (+2M ozs.) of gold in reserve at an overall grade of 2 ppm (0.06 opt). This paper provides a brief history of the property, a summary of metallurgical testing, description of the process flowsheet and discusses design considerations.HISTORY1827 – 1837Gold was discovered in creek beds on the Haile property in 1827. The property was owned by Benjamin Haile, and the first few years of production came from placer mining. After gold was discovered in schist beds to the sides of the streams, Haile expanded the operation by leasing 18 meter-square (50 ft.) plots to local planters. These planters used slaves to work the small excavations in the agricultural offseason. The gold ore was taken to arrastras where the free gold was liberated and recovered. The excavations were above the water table, generally less than 18 meters (60 ft.) down, and it was noted then that gold could be found embedded in sulfides and difficult to extract."

Jan 1, 2013

By A. E. Hilder

Introductory The following pages present the results of field investigations, laboratory and commercial tests, drilling, surveying, and preliminary development of the refractory clays which have been discovered recently in the township of Kipling, at the foot of Long rapids on the west side of the Mattagami river about 57 miles north of Kapuskasing and approximately 7 miles north of Smoky Falls, the terminus of the privately owned railway operated by the Spruce Falls Power and Paper Company, Kapuskasing (see Figure 1). Investigations on the clays of northern Ontario have been carried on over a period of seven years by officers of the Ontario Department of Mines, and I am indebted to the information published by that Department in reports by W. S. Dyer and A. R. Crozier, as well as?by Professor R. J. Montgomery, of the Ceramic Department, University of Toronto. It was, in large measure, the data given in the 37th, 38th, and 42nd Annual Reports of the Ontario Department of Mines that led me to make a personal investigation of the Mattagami River clays, with the result that we now have a commercial undertaking that will develop eventually into an industry of considerable importance in supplying the central manufacturing districts of Canada with refractories that heretofore have been largely imported from the United States. An extract from the 42nd Annual Report of the Department, Part III, 1933, page 75, reads as follows: "As for the refractory clay, the deposits are undoubtedly very large, but what is urgently needed is a deposit near the railway under sufficiently shallow overburden for recovery by stripping'. Having previously made an investigation of the clays adjacent to the Temiskaming and Northern Ontario railway, and these clays proving unsuitable, I turned my attention to the outcrops of refractory clays on the Mattagami river, first reported by Keele in 1919. This area offered possibilities within the economically permissible distance from rail transportation.

Jan 1, 1935

By Chen Lin

Tectonic stress is an important parameter for understanding the dynamics of underground engineering and for the exploitation of coalbed methane. Multiple-period structural features usually have complex spatial relationships in tectonic superposition areas, which provides evidence for identification of the sequence of the tectonic stress period. Conjugated joints and slickensides are used to reconstruct the tectonic stress of the No. 8 Mine in Pingdingshan. Based on the geological unit division and field measurements, data on hundreds of joints and slickensides are collected from 33 stations. The tectonic stress results indicated by the conjugated joints show that there are mainly four directions of tectonic stress: NEE-SWW, NW-SE, NE-SW, and NNESSW. The tectonic stress results of the slickensides indicate that there are mainly four directions of tectonic stress: NNE-SSW, NNW-SSE, NEE-SWW, and NW-SE. According to the systematic analysis of the joints and slickensides, this paper separates the superposed joint and slickenside sets and identifies the tectonic stress periods with their abutting relationships. Three tectonic stress periods are determined and the sequence of the tectonic stress periods is NE-SW, NW-SE, and NEE-SWW. The results are consistent with other tectonic stress measurements for both the region and the locality.

By Chen Lin

Tectonic stress is an important parameter for understanding the dynamics of underground engineering and for the exploitation of coalbed methane. Multiple-period structural features usually have complex spatial relationships in tectonic superposition areas, which provides evidence for identification of the sequence of the tectonic stress period. Conjugated joints and slickensides are used to reconstruct the tectonic stress of the No. 8 Mine in Pingdingshan. Based on the geological unit division and field measurements, data on hundreds of joints and slickensides are collected from 33 stations. The tectonic stress results indicated by the conjugated joints show that there are mainly four directions of tectonic stress: NEE-SWW, NW-SE, NE-SW, and NNESSW. The tectonic stress results of the slickensides indicate that there are mainly four directions of tectonic stress: NNE-SSW, NNW-SSE, NEE-SWW, and NW-SE. According to the systematic analysis of the joints and slickensides, this paper separates the superposed joint and slickenside sets and identifies the tectonic stress periods with their abutting relationships. Three tectonic stress periods are determined and the sequence of the tectonic stress periods is NE-SW, NW-SE, and NEE-SWW. The results are consistent with other tectonic stress measurements for both the region and the locality.

By A. Deepatana

Bioleaching of nickel laterite ores is based on the use of heterotrophic fungi organisms and their metabolites (organic acids) to dissolve nickel and cobalt from oxide minerals to form metal-organic complexes. Metal recovery from this process using an aminophosphonic acid based chelating resin (Purolite S950) was investigated as a function of metal concentrations, complexing agent including citric, dL-malic and lactic acids. Batch adsorptions were conducted using synthetic leachate solutions of nickel and cobalt with concentrations from 15 to 2000 mg/L prepared in 0.01 and 0.1 M organic acids. Adsorption equilibrium data were interpreted using the Langmuir, Freundlich and Dubinin-Kagner-Radushkevich (DKR) models. The results showed that equilibrium adsorption data for nickel-organic complexes followed the Freundlich model and those for cobalt agreed with the Langmuir model. It was observed that the maximum adsorption capacities of nickel and cobalt were 3.26 and 10.48 mg/g resins respectively. These were achieved in metal complexes prepared from 0.01 M lactic acid. Metal elution was conducted using 2 M nitric acid. High metal recoveries were achieved from low metal concentrations but were found to decrease with increasing metal concentration. The results suggest that effective recovery of nickel and cobalt from low concentration of metals, such as those generated from bioleaching operations, can be achieved suitably using chelating resins.

Jan 1, 2006

By Dennis Dolinar

Improperly designed support systems have led to unplanned roof falls in longwall tailgates. To prevent such falls requires appropriate support and adequately designed support systems. The National Institute for Occupational Safety and Health (NIOSH) is currently developing a standing support design methodology based on the ground reaction curve. To design the support system with this methodology requires a quantitative assessment of the ground and support interaction, which is developed from instrumented test sites installed in longwall tailgates. To compliment and expand the field data results and to optimize the support design, numerical modeling is also conducted. The models are calibrated from the test site data. In the present study, data was obtained from a longwall tailgate in the Illinois basin. The test site was located in the Herrin No. 6 coal seam at a depth of 500 ft. At the site, the immediate roof was a weak shale overlain by a competent limestone. Above the limestone, sandstone formed the intermediate roof. The floor consisted of a weak underclay. In the study, the performance and interaction with the surrounding rock mass of two different standing supports, an engineered crib and a conventional 4-point wood crib were monitored. The two cribs have similar load-displacement characteristics at least through 6 in of displacement. Beyond 6 in, the engineered crib becomes unstable and begins to strain soften and shed load. The measurements and developed ground reaction curves indicated that the tailgate at the mine was a low convergence environment until well inby the face. Because the convergence was well below their capacity, both supports provide more than adequate levels of support to the tailgate. Significant convergence and support loading did not occur until 90 to 100 ft inby the face. The results of this study were also compared with results from similar studies conducted in the Pittsburgh seam to further advance the development of the ?ground reaction curve? based support system design.

Jan 1, 2009

By Walter Smith

Environmental Quality Committee ?EQC was created in 1995 to facilitate dialogue between industry and northern communities and help build the understanding of the industry in those communities. ?EQC is made up of representatives from 32 northern communities. ?Meet regularly with Cameco to discuss on going and new projects. ?Tour mine sites on a yearly basis.

Nov 1, 2011

By M J. Kongas, K M. Saloheimo

This paper presents the art of on-stream particle size and elemental analysis used at iron ore concentrators, followed by the results and experiences from several sites.Online particle size analysis is rather common at medium- to large-sized concentrators. Online X-ray fluorescence (XRF) elemental analysis, however, is only used in some iron ore concentrators, while it is a routine practice in base metal concentrator plants. Online XRF analysis is applicable for process monitoring and control down to four to five per cent silica by measuring Fe assays accurately. With lower silica content, direct measurement of silica and other light elements is required. Some light element analysers that are based on the prompt gamma neutron activation analysis (PGNAA) method have been developed, but they have not performed up to expectations with slurry analysis. Other methods have been tried though these have not been used beyond prototype installations. Operating online light element slurry analyser installations are not common in iron ore applications.There is an economic incentive to mine lower and variable grade iron ore resources, which require concentration and removal of several impurities to produce high-quality concentrates for pellet production. Monitoring such operations by on-stream analysis has significant economic benefits, and there is a need to develop a dependable slurry online analyser for Si, Al, Mg and other light elements. The latest developments in slurry on-stream light element analysis are described.CITATION:Kongas, M J and Saloheimo, K M, 2013. Online slurry analysis for process control and monitoring at iron ore concentrators, in Proceedings Iron Ore 2013 , pp 303-308 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By Tristan Worsey, Nathan Rouse, Kyle Hall

Drilling accuracy is the foundation to any successful blast operation. Even the best blasting practices cannot overcome poor drilling and still obtain desired results. Inaccuracies in boreholes can result in flyrock, increased vibration, uneven floor, and other undesired effects. As depth increases, variation in actual burden and spacing is expected even if collars are located precisely. Problems arise when this deviation reaches a point where it adversely affects the function of the blast design. Not only can unsafe conditions such as insufficient burden at the face develop, but poor fragmentation can compound adverse effects. As with any troubleshooting, problems cannot truly be fixed if they cannot be measured. As a result, significant work has been done in the past on this subject. Currently, there are both cheap and expensive methods used to quantify deviation for a given borehole. However, implementation of these techniques is limited. In general production blasts, little is known about the variance in designed versus true borehole geometry. This is especially true if the blaster does not see telltale signs of drilling deviation. However, losses in blast performance may exist and provide an opportunity to obtain better fragmentation and reduce fines. As drill and blast operations strive for better optimization, greater focus is being placed on drilling accuracy and solutions to this problem. The following paper details the use of several current methods for deviation measurement in order to help prevent compromises of safety and improve overall blast performance.

Jan 1, 2018

By J. E. Nesset, F. Rosenblum, J. A. Finch

"The self-heating of sulphides can be a major hazard in mining operations and concentrate handling, particularly during transportation and associated storage. Self-heating results from the oxidation of sulphide minerals and can vary from being insignificant to highly reactive and potentially hazardous to both humans and infrastructure. It is essential that there be a reliable test methodology that can measure and categorize a given sulphide material as to its self-heating potential. By their nature, sulphide ores and concentrates are complex and variable mineral mixtures making it difficult to predict their self-heating behaviour a-priori based on mineralogy or with a simple “snapshot” test. Furthermore, self-heating behaviour will depend on the state of oxidation of the sulphides as well as time, temperature and humidity. A review of available testing apparatuses and protocols that can be used to assess self-heating potential is presented. Each of these methodologies was examined in relation to its ability to measure and reliably predict the latent self-heating hazard of a sulphide material. Several of the methods were tested and compared to illustrate their strengths and weakness. The results indicated that a number of the test protocols may produce false negative indications of self-heating potential, constituting an obvious concern to the industry.INTRODUCTION Sulphides as well as other materials (coal, wood chips, hay, powdered milk, to name a few) that are stockpiled in an air atmosphere may undergo oxidation reactions which can result in the evolution of heat (Beever, 1984) (Hudak, 2002) (Blanchard, 2007). If the rate of heat generated exceeds the rate of heat dissipation, the stockpile temperature will rise, potentially leading to “hot spots” in the most reactive areas, and possibly even fires. The heat generation rate, the “self-heating” rate, depends on many factors such as the type and composition of material, particle size, moisture content, oxygen availability, ambient temperature and humidity, and of prime importance, the extend of prior oxidation, or more specifically, the presence of oxidation products. The desire of operators that mine, process or transport sulphide-bearing materials with a potential for self-heating is to have an accepted and reliable method for evaluating and quantifying the potential hazard of their material. The challenges are how to best measure the self-heating properties of given samples, and based on results, predict the behaviour of the bulk material over time and in-situ. Generally, when evaluating a given material one derives the self-heating characteristics of that sample at the time and under the conditions of testing, which will be referred to as a “snapshot test”. If that material is invariable, i.e. it will not change its response over time, then it may be considered to be a “predictive test”. However, if as a result of continuing oxidation or other changes, the material becomes more or less reactive with time, then a “snapshot test” is unreliable with respect to predictive ability."

Jan 1, 2014

By M. A. Oskouei

Draglines are the main energy consumers in strip mines. Given the growing cost of energy and environmental concerns, it is important to properly understand dragline energy efficiency. The goal of current research at Missouri University of Science & Technology is to account for operator practice and operating conditions in modeling dragline energy efficiency. This paper presents preliminary correlation analysis and a framework for stochastic modeling of dragline energy efficiency. Thirteen operating parameters (including cycle times, payload, swing angle, and height of dump pile), operator working schedules, operating conditions, and drag, hoist, and swing energies were monitored for an 85 yd3 dragline. Operator effects were examined by two-sample t-tests. The relation between the parameters and energy consumption were assessed by correlation analysis and a stochastic modeling framework has been proposed for dragline energy efficiency. The results show that operator effects are significant (p< 0.05) and energy efficiency is correlated with operating parameters. The completed model will help the coal mines better predict energy consumption, with uncertainty, for different operating conditions.

Feb 27, 2013

By A. Sariisik

This study analyses the results of a pilot trial of a newly developed armed-chained stone-cutting machine. The machine was developed in Turkey and trialed at the Kaklik/Kocaba travertine quarries in the Denizli District. An armed-chained cutting machine is an alternative to the diamond wire cutting method more frequently used in the production of natural stone quarry blocks, and increases production efficiency and quality. Since there is no need to collapse the blocks using the armed-chained cutting production process, there is no risk of the block developing cracks. This results in a considerable increase in the efficiency of natural stone block production. The armed-chained cutting machine is easier both to assemble and run when compared to other block cutting methods. This process resulted in the production of a larger number of blocks at a lower cost within the same time frame, particularly in travertine quarries and in all other natural stone quarries. The block efficiency in travertine quarries was calculated as 65?80%using the armed-chained cutting machine, compared with 7?14% using the normal diamond wire cutting method.

Jan 1, 2010

By Charles L. Guild

I will add a few facts about the use and development of the Osterberg Test Load Cell and my association with Jorj. I first met Jorj in 1965 when the Guild Construction Co. drove 12" diameter cast-in-place shell piles for him at the Marquette Cement Co. in Nashville, Tennessee. When I met Jorj at the DFI Trustee&apos;s meeting in 1985 at Longboat Key, Florida, he showed me a sketch of his idea about using a test cell at the bottom of a caisson to test the end bearing and side friction on a caisson. He had made a successful trial test in Case International&apos;s equipment yard and wondered whether a similar device could be made for a driven pile. At first I was skeptical that it could be done but after thinking about it overnight I told him I felt it was feasible and we would do some work on it. At that time, there was a large bridge job going out for bid in Rhode Island using 14" square prestressed concrete piles&apos;. Based on a record of the Guild Construction Co. Inc. driving over 3,000,000 feet of piling on work for the State of R.I., we felt we would have an excellent chance to be allowed to use them so we designed, detailed and fabricated three for 14" square prestressed concrete piles. As things worked out, we did not test them on this job and have not to date.

Jan 1, 1989

By Rolf Birger Pedersen, Alden Ross Denny

"Synthetic Aperature Sonar (SAS) is a powerful tool for ultra-high resolution marine survey. The Kongsberg HiSAS system deployed on the HUGIN AUV has a rangeindependent resolution of 3x3 cm for sonar image and ~10x10cm for the interferometric bathymetry product [1]. This resolution is achievable for areas up to 50 km2 on a single survey mission providing huge multi-attribute datasets. This technology, originally designed for military and oil-industry applications, has the potential to revolutionize scientific seafloor mapping. The extreme resolution of this technique allows for deposit mapping in and around seafloor hydrothermal systems, including the discovery of extinct venting structures. By clearly distinguishing between volcanic and hydrothermal landscapes based on features below the resolution of conventional multibeam systems, SAS enables an entirely new level of hydrothermal deposit survey. Additionally due to the extreme resolution of this survey technology, repeat survey and change detection should allow centimeter-scale changes in deposit morphology to be routinely detected over an entire hydrothermally venting region. In collaboration with the EU funded MIDAS project, the Centre for Geobiology at the University of Bergen will deploy the HUGIN AUV this summer at two distinct shallow venting systems on the Arctic Mid-Ocean Ridge system. The AUV will collect repeat bathymetry at the Jan Mayen Vent Field, and extend the SAS coverage to include newly discovered venting sites. We will present the preliminary findings of this expedition, including the first deposit estimations made from full-resolution SAS mosaics."

Sep 1, 2014