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By L. S. Trenholme

"Belleterre Quebec Mines, Limited, is a subsidiary of Mcintyre Porcupine Mines, Limited. The property is in Guillet township, Quebec, 45 miles due east of Haileybury, Ontario. It is accessible by 72 miles of gravelled road from New Liskeard, Ontario (Fig. 1).Gold production at the property commenced in 1936 and to March 31st, 1945, had exceeded $9,000,000. For the past 3 years the milling rate has averaged 325 tons a day and the gold recovery about $14 a ton.GENERAL GEOLOGYThe rocks of the district consist of Keewatin-like volcanics conformably overlain by Timiskaming-like sediments. Together they form the remnant of an easterly plunging anticline engulfed by granite (Fig. 2). The pregranite intrusives consist of diorite, gabbro, and ultrabasic rocks, occurring as dykes, sills, and irregular stocks. Dykes of porphyry and lamprophyre presumably related to the batholithic intrusive are common in this area. The veins of quartz are also probably derived from the batholithic intrusives. A few dykes of Keweenawan-type diabase have been observed."

Jan 1, 1954

By Sudarshan Martins

The measurement of acoustic signals produced by a tumbling mill has been previously used to determine the operating state of the mill and correlate the variations of the sound intensity with the operating conditions of the mill. Separately, the discrete element model (DEM), a software simulation of the mill, was developed to provide insight into the operation of the mill. Presently, there has not been much work reconciling the DEM simulation of the mill with the acoustic signal. Working from basic principles of linear, time-invariant systems, agreement between an acoustic DEM simulation and the measured signal is sought. First, the impulse response function of the mill is measured. The DEM provides the forces applied to the mill shell as a function of time. A convolution of these simulated shell forces and the transfer function gives the simulated acoustic signal. This signal is compared to the measured acoustic signal, both in the time domain and the frequency domain. Finally, a discussion of the results is given.

Jan 1, 2012

By Peter C. Jones, Wanda M. Carter, David H. Watkinson

"Abstract - Pyrrhotite, chalcopyrite, and pentlandite are the dominant sulfide minerals in the 740 zone of the Kelly Lake orebody (Inco Ltd.), Copper Cliff Offset, Sudbury. Petrographic and quantitative electron microprobe analyses of minerals, from sulfide assemblages and host quartz diorite, of the 740 deposit have revealed three processes that have affected sulfide mineralization and associated sulfarsenide and platinum-group-mineral (PGM) distribution: magmatic, hydrothermal, and tectonic. Accessory, zoned cobaltite, and gersdorffite occur in sulfides as a result of these three processes, and PGM occur dominantly in hydrothermally remobilized and deformed ores. Where PGM are present in sulfarsenides they provided nuclei for sulfarsenide growth. Solitary PGM are orders of magnitude larger than those PGM found within sulfarsenide minerals. Five varieties of PGM occur, michenerite and sperrylite being the most common, with lesser froodite, hollingworthite, and ruarsite.The effect of a deformation is a localized fabric in the ore, revealed by pyrrhotite and chalcopyrite bands; pentlandite porphyroblasts also partially define the foliation. The deformed ore is also characterized by alteration of the adjacent quartz diorite, which produced an alteration assemblage including almandine garnet, Fe-rich biotite, and chlorite."

Jan 1, 2001

By Y. P. Malhotra, JE. C. Carter

"Syncrude's overburden removal requirement ranges from 20 million to 30 million bank cubic metres per year to meet tarsand demands for the production of 129,000 barrels of synthetic crude oil per day. The economic tar-sand lies beneath a variable thickness of overburden materials, composed of silts, clays, some sands of lacustrine origin, wind-deposited sand dunes, and out-wash sands and gravels.For the removal of overburden, Syncrude commissioned its own mobile equipment fleet in January 1981. This fleet consists of two Demag 241 hydraulic shovels, ten Titan 33-15B trucks and support equipment. Prior to this, all overburden removal was being carried out by contractors.This paper presents an overview of overburden removal at Syncrude, with particular reference to the performance of its own fleet.IntroductionThe Syncrude Tar Sands Plant was officially opened on September 15, 1978. After an expenditure of approximately $2.26 billion, the second and the largest commercial tarsands plant was on stream toward a permit production rate of 129,400 barrels of synthetic crude oil per day. The Syncrude Plant, a joint venture of six oil companies, the federal government and the Alberta government, is a major step forward toward the goal of Canadian energy self-sufficiency.The Mildred Lake operation of Syncrude Canada Ltd. Is located 40 km north of Fort McMurray and 480 km northeast of Edmonton in the Province o f Alberta.Synthetic crude oil leaving the plant is a blend of two-third s gas oil and one-third naphtha. The two streams combine in a pipeline and flow to Edmonton. The product takes six days to make the journey, arriving at four locations in the city Imperial's Strathcona Refinery, Gulf's Edmonton Refinery, the Interprovincial pipeline terminal and the Trans-Mountain pipeline terminal. Each Syncrude owner receives a share of oil equal; to its percentage of ownership in the project. At the present time, the oil is being utilized by Canadian refineries from Vancouver to Montreal."

Jan 1, 1983

By S. Dessureault, M. Yildirim

More mining companies are now investing in IT, including updating one of the traditional IT process control tools used in the mining industry: real time in-pit truck allocation control and monitoring systems, or fleet management systems (FMS). These systems have been used to maximize the overall mine production by improving equipment utilization and reducing production costs. Most modern operations monitor the in-pit operations using GPS and wireless communications to produce data. Improvements in bandwidth, sensors, and computing power are causing modern systems to become more complex and generate more data. However, human analysis by simple regression or table generation in spreadsheets of the data is becoming impossible. Data mining solves this data management problem. Data mining finds patterns and relationships in very large data sets. This paper describes the application of modern data mining techniques on truck dispatching systems in a real open pit hard-rock copper mine. The analyses conducted included determining how the trucks performed under particular conditions and allocation systems. The long-term benefits of this work are to identify strengths and improvement opportunities in truck assignment systems and establish the skill sets and IT infrastructure needed in undertaking more complex datadriven technology such as a truck dispatcher trainer.

Jan 1, 2007

By Lisa L. Van Loon, Neil R. Banerjee

Canada is a world leader in uranium exploration, but many deposits are located in remote regions making exploration targeting challenging. Novel approaches are needed to detect the presence of large-scale ore-forming systems and to vector toward mineralization. Boron is commonly used as a key pathfinder element associated with sandstone/unconformity-hosted and basement-hosted uranium deposits in the Athabasca Basin, but the genetic relationship remains uncertain. Alteration assemblages containing boron geochemical anomalies are commonly spatially-associated with – and possibly coeval with – uranium mineralization. Boron is commonly found in tourmaline minerals but in some portions of ore deposits the host mineral for the anomalous boron remains cryptic. Boron coordination chemistry within alteration haloes can better constrain boron host mineralogy, provide insight into the nature of the boron-uranium relationship, and thus has the potential to better constrain targets for exploration. Synchrotron-source X-ray absorption near-edge structure (XANES) spectroscopy is a direct, element-specific analysis that identifies boron coordinated in both trigonally- (BO3) and tetrahedrally-coordinated (BO4) forms. This makes XANES uniquely suited for identifying the geochemical hosts for boron that may be related to hydrothermal ore forming processes. XANES spectroscopy was conducted on whole-rock assay powders from uranium deposits across the Athabasca basin containing boron concentrations ranging from <10 ppm to >10,000 ppm. XANES directly identifies the relative amount of trigonally- (BO3) and tetrahedrally-coordinated (BO4) boron in these complex mineralogical mixtures. Our work suggests a link between boron and uranium that is likely related to the unique physiochemical characteristics of ore bearing fluids that may provide a unique vector to mineralization.

Jan 1, 2020

By J. A. Bossert

"In 1957, the Department of Mines and Technical Surveys (now Energy, Mines and Resources Canada) issued their first certificate for a fire-resistant conveyor belt. The testing procedure used was a combination of those used in the U.S.A. and the U.K. Subsequently, certification was granted to fire resistant electric cables (1974), fire-resistant mine duct material (1976) and fire-resistant hydraulic fluids (1978).Until recently, the testing procedures were copied from either the U.S. or the U.K. However, since the founding of the new Canadian Standards Association (CSA) Steering Committee for Electrical/Mechanical Mine Safety in 1981, these requirements have come under the close scrutiny of new CSA technical committees who will attempt to adopt or change the existing procedures to meet Canadian needs. This paper outlines the existing test requirements and attempts to predict how they will appear after ""Canadianization"" by the CSA committees.IntroductionFires in underground mines have always been considered more serious than in other locations because of the confined space and limited atmosphere. A fire can make escape difficult or impossible if it is blocking all of the routes to the surface. Also, the products of combustion from an underground fire can asphyxiate anyone not having self-contained breathing apparatus.In an underground coal mine, the consequences of a fire can be even more serious because of the presence of methane and coal dust in the atmosphere (which can explode) and because the coal itself is combustible.For these reasons, the inspection authorities having jurisdiction over underground mine s in Canada are quite concerned about the flammability of any materials that are used in quantity in the underground environmentAs early as 1957, the Canadian Explosive Atmospheres Laboratory (CEAL) was asked to certify conveyor belting as fire-resistant. This is because many miles of this material are used in underground mines in Canada and, as it generally travels through the mine, it is a perfect vehicle for spreading a fire."

Jan 1, 1982

By Todd Smith

AGENDA Newalta overview Dewatering underground slimes: current technique & challenges Why centrifugation? Process improvements & advantages How centrifuge technology works Implementation: first step Summary of benefits

May 1, 2013

By C. W. Hancher, B. D. Patton, W. W. Pitt

"There are a number of nitrate-containing wastewater sources, as concentrated as 30 wt % NO3 and as large as 2000 m3/day, in the nuclear fuel cycle. The biological reduction of nitrate in waste water to gaseous nitrogen, accompanied by the oxidation of a nutrient carbon source to gaseous carbon dioxide, is an ecologically sound and cost-effective method of nitrate waste disposal. These nitrate-containing wastewater sources can be successfully biologically denitrified to meet discharge standards in the range of 10 to 20 g N(NO3-)/m3 by the use of a fluidized bed bioreactor. The denitrification bacteria are a mixed culture derived from garden soil; the major strain is Pseudomonas. In the fluidized-bed bioreactor, the bacteria are allowed to attach to 0.25- to 0.50-mm-diam. coal fluidization particles, which are then fluidized by the upward flow of influent wastewater. Maintaining the bacteria-to-coal weight ratio at approximately 1:10 results in a bioreactor bacteria loading of greater than 20,000 g/m3,This paper describes the results of a bio denitrification R&D program based on the use of fluidized bioreactors capable of operating at nitrate levels of up to 7000 g/m3 and achieving denitrification rates as high as 80 g N(N03-) per day per litre of empty bioreactor volume. IntroductionThe discharge of wastewater containing nitrate at concentrations greater than stipulated by the Environmental Protection Agency (EPA) creates an environmental hazard and constitutes a civil and/ or criminal legal liability.(I.2) At present, we have three options: (1) recycle and reuse of nitrate streams the total economic and technical balance should be Closely examined; (2) use of an alternative acid, which may pose an entirely different set of problems ; or (3) disposal of nonreusable nitrate sources by an environmentally acceptable procedure."

Jan 1, 1980

By J. T. Chen, S. Winkler, M. J. Worswick, O. Orlov

This paper presents a review of research conducted at the University of Waterloo concerned with the application of aluminum alloy sheet and tube in automotive structures and body panels. The research has focussed on formability prediction and results using a range of damage-based formulations. These models include continuum-level damage approaches and, more recently, a so-called percolation damage approach intended to capture microstructural heterogeneity effects on damage development. This paper presents applications of these damage approaches to simulate formability of experiments considering stretch flange panels. The experiments consider drawbead effects associated with the bend/unbend deformation as the material flows through the drawbead. Recent work on simulating in situ X-ray tomography experiments that capture damage evolution during tensile deformation will also be reviewed.

Jan 1, 2006

By R. B. Smith, D. C. Brady

"A review of the major renovation of the fifty-year old C-I headframe facilities at NERCQ&apos;s Con Mine, Yellowknife, N. W.T. is provided. The project was complete with only two 3-day shutdowns of the facility .Work consisted of four major phases: structural reinforcement of the adjoining mill building prior to dismantling; relocation of virtually all mine and mill utilities which transited the headframe collar en route from the adjacent powerhouse; dismantling of the entire headframe facility and portion of the mill building, including the removal of asbestos siding; and erection of a new headframe, idler rower, collarhouse and mill wall.This paper describes the work and methods used by NERCQ, J.S. Redpath Mining Consultants Limited, Acres International Limited, and others to bring the project to a successful completion. The history of the project is discussed from the planning phase through construction, including; design, procurement, and construction scheduling. The paper discusses the unique elements of the project, the problems encountered, and the methods used to achieve success.IntroductionThe Con Mine is a 800 tpd gold operation located in Yellowknife, Northwest Territories. Originally owned and operated by Cominco Limited , the Con Mine was sold in December 1986 to NERCO Minerals Company, and officially renamed NERCO Con Mine, Ltd. The Con Mine has been in operation for over 50 years. The first gold brick ever produced in the Northwest Territories was poured at the Con Mine in 1938. The original C-1 shaft was sunk in 1937 to a depth of 235 ft. In 1941 the shaft was deepened to a depth of 950 ft, and the original timber head frame was replaced with a steel structure. Following the discovery of the Campbell Shear in 1946, the C-l shaft was again deepened to its present depth of 2443 ft. Over the years, mine production gradually moved deeper and further from the C-l shaft."

Jan 1, 1991

By J. Jara

Oxygen, ozone and air were evaluated in the oxidation of ferrous iron in the presence of hydrochloric acid ranging from 0.1 to 4 M HC1. Stoichiometric coefficients were determined through mass balances of gases and ferrous titration. The molar ratio ferrous to ozone increases from two at 0.1 M HC1 concentration to six at 4 M HC1. For oxygen the same ratio is constant and equal to 2 and it is in agreement with other works. The stoichiometric coefficient of hydrogen ion was not defined due to the effect of hydrolysis of ferrous and in particular ferric ion on measuring acid concentration by titration with sodium hydroxide. Agitation, gas flow and pressure contribute in the utilization of gas. A technique to compare the gas efficiency at several conditions is discussed and it is based on the relationship between oxygen and ferric during time. There is a strong compromise between gas efficiency and ferrous conversion. Oxygen efficiency decreased with time due to ferrous depletion. The gas efficiency ranged from 3 % (low level of agitation) producing 25 g Fe(III)/h to 12 % at 1000 rpm with 60 g Fe(III)/h converted. At 405 kPa absolute the oxygen efficiency was in the range of 80 % producing 300 g Fe(III)/h. The replacement of chlorine with oxygen to enrich molybdenite concentrates by reducing copper to less than 0.2 % was evaluated. Oxygen can be employed in batch or continuous operation and it can treat molybdenite concentrates with high variation of copper content. The dissolution rate is mainly controlled by oxygen addition in which utilization of oxygen plays an important role. Improvement on safety and environmental conditions is feasible by using oxygen instead of chlorine gas. The economics indicate good opportunities to implement oxygen without significant modifications to the actual circuit and enough benefit when oxygen is well used.

Jan 1, 2007

By Gordon L. Kidd

The object of this paper is to show the relations of the East Coulee coal area to the near-by Willow Creek, Wayne, Rosedale, and Drumheller areas, all being parts of the Drumheller field. The word ?area? is here used in a more local sense than that employed by Dr. J. A. Allan, whose. &apos;area&apos; is rather comparable with the &apos;mining division&apos; in British Columbia. I have drawn freely from the published information, particularly from Dr. Allan&apos;s report on the "Geology of Drumheller Coat Field, Alberta", and from Dr. E. Stansfield&apos;s paper on " A Chemical Survey of Alberta Coals", to whom thanks are due. The Drumheller field is served by branch lines of the two principal Canadian railways. The C.N.R. traverses the district by its Goose Lake line from Calgary to Saskatoon; and the C.P.R. by a line from Calgary to Acme and then southeasterly to Drumheller, where it effects a junction with the C.N.R., over which the C.P.R. has running rights as far as Rosedale. From Rosedale, a joint line built during the summer of 1928 extends about forty miles down the Red Deer river to the mouth of Bull Pond creek. From that point the C.P .R. turns more southerly to connect with the Bassano-Empress line. The C.N.R., it is expected, will eventually proceed eastward to connect with a transcontinental line. The joint line from Rosedale down the Red Deer river opened up the Willow Creek and East Coulee areas.

Jan 1, 1929

By Rene Klymowsky, Norbert Patzelt, Egbert Burchardt, Johann Knecht

"The challenge of ""ore bodies getting steadily harder and lower in grade"" was brought to light during the first oil crisis in the 70&apos;s. Shortly afterwards, HPGRs appeared on the scene with the promise of saving energy. This combined with developments in wear protection for the rolls ushered in a period of trade-off studies that considered the HPGR as an option to improve project economics or to even make projects feasible at all.Since then, applications of HPGRs at Cerro Verde (Freeport), PTFI Grasberg (Freeport), Mogalakwena (Anglo Platinum), Tarkwa (Goldfields), Boddington (Newmont), Penasquito (Goldcorp), and others have contributed to the creation of a formidable basket of operating experience. Collected through years of successful operation, this information has been used to validate design criteria, scale-up factors and establishing a clearer picture of what ""to do"" and what ""not to do"".This paper compares results from various mining operations using HPGRs in their processing plants. Some of the lessons learnt in different operating environments are reviewed in order to support proper implementation and operation of HPGR&apos;s. Some of the development programs that have been initiated to improve wear life of the tyres and to reduce overall operating costs are reviewed. It is timely to summarize today’s experience and analyse its implications for existing and new operations"

Jan 1, 2012

By Morris Wong

"An antimony-bearing gold ore was studied in a cyanide slurry containing 7 -20 ppm dissolved oxygen. 1 g/L NaCN at pH 9.5 and 48 hours retention time is required to extract 94 % of the gold from the 90 % minus 200 mesh ore by conventional cyanidation at a 7 ppm O2. As oxygen concentration was increased to 20 ppm, the conditions required to extract the same amount of gold were: 0.25 g/L NaCN, 16 hours retention time and 80% minus 200 mesh. Compared to conventional cyanidation, oxygen-enriched leaching was shown to reduce retention time by three times and cyanide consumption by four times. The kinetics of gold dissolution related to the dissolved oxygen concentration in slurry was expressed by following equation:XAu = 100 * (Kt + I0) / (1 + Kt + I0)where XAu is the percentage gold extraction; t is the retention time; K and Io are the slope and the intercept of the plot of XAu I (100 -XAu) vs. t respectively. The values of Kand Io depend upon the concentrations of cyanide and oxygen, the fineness of grind and the origin of ore sample etc.. A preliminary cost analysis was also performed to justify the use of oxygenating slurries.IntroductionGeneral:It was proposed almost 149 years ago (Elsner 1846) that oxygen is required for the dissolution of gold in cyanide solution. However, little attention were paid to oxygen application in the gold milling industry during the following one hundred years. Due to the constraints of gold price, reagent costs, refractory ores, and environmental issues in the past decade, the oxygen enhancement in the cyanidation process was introduced to the gold milling industry for increasing operation efficiency, reducing production costs, and meeting the requirement of environmental standard.The advantages of oxygen-enriched cyanidation have been reviewed by several investigators (Hague 1992, Jara et al 1992, Henderson 1989, Loroesch et al 1988, Elmore 1987, Cathro 1963). Common to all conclusions are the following advantages."

Jan 1, 1995

By E. Godin, M. Rigaud, S. C. Panigrahy, I. Malinsky

"RésuméDes boulettes de concentres d&apos;hématite spéculaire à basse silice ont été produites en substituant la bentonite par de la tourbe, adéquatement traitée, additionnée d&apos;une faible quantile de soude caustique durant le boulettage. La réductibilité de telles boulettes et leur gonflement pendant la réduction ont été évacues, en utilisant quatre mélanges gazeux différents, formes de H2 - CO - N2.L&apos;influence du pouvoir réducteur du gaz utilise, sur le gonflement des boulettes, à été mis en évidence. Quelles que soient ces conditions réductrices, les propriétés mesurées sur les boulettes liées a la tourbe sont comparables aux propriétés obtenues avec des boulettes traditionnelles liées à la bentonite.ABSTRACTAdditions of peat moss and small quantities of NaOH during balling of low silica specular hematite concentrates have eliminated the need to use bentonite as a binder. The reducibility and swelling of such pellets have been evaluated using four different gas mixtures, consisting of H2 - CO -N2. The influence of the reducing power of the gases, on the swelling behaviour of pellets has been documented. Under the different reducing conditions, this new type of pellets exhibit properties similar to the ones obtained using bentonite."

Jan 1, 1987

By George Efremidis, Markos Avlonitis, Elias C. Aifantis, Avraam Konstantinidis

"Nowadays, there is an increasing interest for realistic spring-block models capable of addressing precursor phenomena in catastrophic earthquake-induced landslides. By pre-defining the constitutive law between externally applied stress and induced local strain increments, the dynamic behaviour of the rock/soil slope can be studied by means of the distribution of slip events at the interface between the soil and the bedrock. It is shown that by relaxing the assumption of constant of externally applied stress rate and local strain increments, a robust 2D spring-block model can be formulated for studying triggered landslides. A cellular automaton is built in order to examine the dynamic behaviour and the stability of rock/soil slopes during the initiation of a landslide. The type and nature of the failure plane, as well as the triggering mechanism is studied. The different dynamic evolution modes of the slope can be mapped to specific shape parameters of the corresponding distributions of the incremental displacements. The proposed spring-block model can be used in order to understand, predict and minimize the impact of catastrophic landslides triggered by earthquakes.INTRODUCTIONEarthquakes have long been introduced as one of the major cause of landslides. Earthquake induced landslides are of great importance because they can cause considerable damage and life casualties. Existing analyses can provide landslide concentration, i.e. the number of landslide sources per square kilometer of surface area, as well as the distance from the earthquake source, which is related to the strength of shaking, the slope steepness, which is connected to shear stress, and finally the rock type, which is referred to material strength (Keefer, 1984). In spite of their great importance in social and economic life, earthquake-induced landslides are still considered as an open geotechnical problem. The dependence of the number and distribution of landslides on earthquake magnitude and ground shaking intensities is a crucial factor for the description and determination of the phenomenon. The hazardous types of earthquake-induced landslides, the most susceptible geologic materials and the reactivation of landslides originally triggered by nonseismic activity are some important topics for areas affected by landslides. Most of these areas present an irregular and asymmetric shape with respect to epicenters and fault ruptures, and also show a strong correlation with magnitude (Keefer, 1984, 2000). The number of landslides caused by an earthquake generally increases with increasing earthquake magnitude. Keefer (1984) presented a magnitude scale in order to quantify the number of earthquake-induced landslides. Malamud et al. (2004) have proposed an independent landslide-event magnitude scale on the earthquakes, based on the logarithm of the total landslides number associated with an event. The aforementioned studies try to relate the landslide magnitude scale to the visible effects of the triggering mechanisms."

Jan 1, 2015

By Markus Timusk

This paper describes a research project that focuses on developing a diagnostic routine to assist in decision support for the condition based maintenance of mobile mining equipment subject to unsteady duty. The objective is to develop a general method for initial identification of mechanical faults in machinery operating under non-steady state conditions. The platform to be used for the experimental development and validation of the system is the swing machinery in an electric mining shovel operating in an open pit mining environment. The strategic approach that is proposed for the diagnostic routine will involve using novelty detection augmented by temporal classification.

May 1, 2004

By S. C. Tadolini

"Roof bolts are the primary means of roof support in underground mines in the United States. Presently, post installation loads are measured on about 10% of the expansion anchor and combination bolts by using standard torque wrenches that Unit the accuracy of the measurements to about ±30%. No system has been available for measuring the loads generated on full-column resin grouted bolts. Mine roof bolts are long, slender, non-uniformly sized, roughly forged, and placed in a corrosive environment, creating obstacles for researchers trying to utilize ultrasonic reflection techniques to measure strain. A complete measurement system has now been developed by the U.S. Bureau of Mines, Denver Research Center. This system is being used successfully in determining loads measured on expansion anchor and combination bolting systems, examining the transfer mechanics of full-column, resin-grouted bolts, and measuring loads generated on bolts in an underground roadway support system.IntroductionMillions of roof bolts are used each year to provide structural support in underground U.S. metal, non-metal, and coal mines. Approximately 45% of the bolts used are expansion anchor, 45% are resin-assisted combination or full-column resin-grouted, and 10% are friction anchored. The effectiveness of these bolting types is dependent on a number of factors including rock density, bolt length, in situ stresses, rock properties, bolt pattern, installation tension, etc. When implementing expansion anchor and resin assisted combination bolts , installation and post-installation tension, or load, is a major determinant of support quality and subsequent behaviour of the reinforced roof. The method by which these systems carry roof loads is well understood and documented(1,2).The importance of these installation and long-term bolt tension measurements is well recognized and are required in the federal government regulations(3). A statistical sample of the bolts, lout of 4 during installation and lout of 10 inby the last open crosscut, is required to be measured using current torque wrench technology. The disadvantages of this system are the disturbance and weakening of the anchorage and limitations of accuracy to approximately ± 30%. The method by which resin-grouted bolting systems carry roof loads is much less understood, mainly because testing procedures used to evaluate point-anchor systems are not effective on resin-grouted bolts.Due to these problems, the U.S. Bureau of Mines designed a measurement technique that provided a highly accurate, low cost-per- bolt system that led to the development of ultrasonic pulse echo instrumentation. The original system was designed to measure the tension only on expansion anchor bolts. Recent developments and system modifications have permitted measurements on resin-assisted and full-column resin-grouted bolts. The use of these types of support systems has been increasing steadily in underground coal mines.The development of this instrumentation has provided laboratory and field results that help to explain the mechanics and relationships between the applied loads and the interaction between the grouted bolt system consisting of the bolt tendon, grout, and rock."

Jan 1, 1990

By S. Yadav, T. G. Murthy, C. Saldana

"An experimental study has been carried out in order to study the deformation of porous brittle materials under plane strain indentation. Gypsum, which is well known model system for understanding the behaviour of soft rocks, is used in this study. The effect of wedge angle is investigated in this research through this series of experiments, using wedges of 3 different apical angles. High-speed, high-resolution images are captured using a CMOS camera during the experiment. The images obtained are analyzed using a Particle Image Velocimetry (PIV) algorithm in order to obtain the evolving velocity, strain-rate and strain fields.INTRODUCTIONThe problem of indentation, which is usually referred to in the context of hardness testing is ubiquitous as a material characterization technique for a large class of solids. Mechanical properties of materials such as yield stress, flow stress, fracture toughness, elastic moduli etc. can be related to the hardness of a given solid. The indentation problem involves a given material or solid (whose properties are to be determined) indented by a relatively harder material (indenter) allowing the solid to undergo plastic deformation, which is then related to the yield stress of the material. The problem of indentation and its variants see many applications ranging from mining and petroleum industry, infrastructure industry, manufacturing, and biomedical sectors. Indentation has been extensively studied in metals, with accurate measurement of deformation parameters, stresses and comparison with analytical solutions. On the other hand, understanding of indentation in other class of solids such as cellular solids, porous solids, rocks, and soft solids is still nascent. In case of rocks, a comprehensive understanding of the indentation problem is very crucial because of the obvious applications in mining, petroleum and infrastructure sectors. The inherent porosity, the brittle nature of the rocks, adds to the complexity of indentation in these porous brittle solids. Various theoretical models with degrees of simplifying assumptions have been proposed to study the indentation in rocks. The most common model used in the study of indentation in rocks is a cavity expansion model, wherein a blunt indenter indenting into a rock is approximated with the expansion of cylindrical or spherical cavity in an elastic-plastic material. Complementary studies in understanding fracture initiation and propagation due to indentation has been largely based on the studies of traditional brittle materials such as glass."

Jan 1, 2015