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By Finn Ouchterlony

INTRODUCTION Much of present fracture toughness testing con¬cerns chevron notched specimens (Newman Jr., 1984) since these, in principle, require neither fatigue precracking nor more registration than failure load to determine fracture toughness. Two such specimens which can be made from diamond drilled rock cores with minimal machining are the Short Rod (Barker, 1977) and the Chevron Edge Notch Round Bar in Bend¬ing or CENRBB Specimen (Ouchterlony, 1980). Even if the precracking property is especially valuable for a material like rock, practice has made the relative advantages of these chevron notched specimens much less apparent (Ouchterlony, 1982; Ouchterlony and Sun, 1983). Enough remains, however, to have the Commission on Testing Methods of the International Society for Rock Mechanics (ISRM) focus on them as standard configurations in a "Suggested Method for Determining Fracture Tough¬ness of Rock Material", which is in preparation. This paper presents material which supports the ISRM effort: 1. An experimental compliance calibration of the Chevron Bend (CENRBB or CB for short) and re¬sulting formulas. 2. Specimen tolerances, evaluation formulas, and loading rate requirements relating to both Short Rod and Chevron Bend Specimens of suggest¬ed standard proportions. 3. Some fracture toughness values obtained with the Chevron Bend Specimen. This material is mainly based on two reports (Ouchterlony, 1984 and 1985). CALIBRATION OF THE CHEVRON BEND SPECIMEN Preliminaries The specimen and basic notation is shown in Figure 1 together with a straight notched variety (SECRBB). Subscripts c and s are sometimes used below to distinguish between them. Assuming linearly elastic conditions the load point compliance [ ]

Jan 1, 1986

By M J M Cunningham, M Greentree, J H Liu

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Palaeozoic rocks of north-eastern Laos are an attractive target for gold explorers due to the complex tectonic history and lack of past exploration in the region. Alluvial workings along the Nam Xiang River and its tributaries have highlighted the potential for gold mineralisation in the Vieng Kham region. The Nam Xiang River follows a regionally-extensive NNE-striking thrust fault. Adjacent to the Nam Xiang fault, the dip of the main foliation steepens, and in many places the stratigraphy is overturned as a result of this faulting.United Minerals and Mining Company conducted a regional exploration program to explore for gold. This included stream sediment and rock-chip sampling, and airborne geophysics. Geochemical anomalies were followed up with more detailed exploration, including geological mapping and soil sampling. Despite the relatively deep weathering profile, gold mineralisation is associated with a low-level but well-defined gold-in-soil anomaly. Drilling has shown that gold mineralisation occurs on structures and fabrics parallel to the main Nam Xiang fault. The highest gold grades are associated with brecciated sandstones that have experienced strong carbonate alteration. This suggests that late-stage structures such as the Nam Xiang fault are the major control on gold mineralisation in the region.CITATION:Greentree, M, Cunningham, M J M and Liu, J H, 2015. Gold mineralisation along the Nam Xiang fault, Vieng Kham Project, North-east Laos, in Proceedings PACRIM 2015 Congress, pp 177–182 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By K. Lang

The use of high-efficiency electrical submersible pumps (ESPs) for large scale, open pit mine dewatering operations provides a good example of how technology, products and services from the oil and gas industry can be adapted to the mining industry. In this case, the mine is Goldcorp?s Peñasquito in the Zacatecas state of Mexico, at the Peñasco and Chile Colorado open pit deposits. The technology, products and services are from Schlumberger artificial lift (AL) and Schlumberger industrial water services (IWS). Overview of high-efficiency ESPs This section provides a brief description of the basic components, specifications and operating capacity ranges for the ESPs compared with traditional or conventional dewatering well pumps. This information helps to establish how ESPs provide certain functional and economic advantages over conventional pumps in a mine dewatering application. A schematic of a high-efficiency ESP in an oil and gas (O&G) application is shown in Fig. 1.

Sep 1, 2013

By Denise Corrêa de Oliveira

Household zinc based batteries, dry and alkaline, has become the most popular sources of electrical energy, and are widely used. Because of their heavy metals content such as mercury, zinc and manganese, spent batteries cannot be directly placed in common landfills without a pretreatment. As a municipal solid waste, these batteries may cause serious health problems and environmental impacts. These damages can be reduced by recovery (which means saving natural sources and energy), recycling and adoption of cleaner technologies. Although this worry has been increasing recently, and producers are doing efforts to reduce the mercury content, batteries still need proper safe disposal conditions or recycling processes. This work presents the efforts in progress to characterize and recycle mixed - dry and alkaline - spent batteries, by using low cost unit operations. Some possible recycling stages and recovery parameters of metals as zinc and manganese are also discussed.

Jan 1, 2001

By P Barrette

The manual gravimetric drying moisture determination methods currently employed by most mineral processing plants fail to provide timely and accurate information required for automatic control. The costs associated with transporting and handling concentrates represent a major portion of the overall treatment price. When considering the cash flow of a mining operation that is governed by both the smelter contract, with moisture penalties and the quantity and quality of the concentrates shipped, any tool that provides real-time feedback on the process is vital (Edwards, RP 1994). The introduction of an on-line moisture sensor would become a welcome addition to the process control field instrumentation package now applied. A novel on-line determination system for ore concentrate moisture content would replace the tedious manual procedure. Since the introduction of microelectronic-based control systems, operators have strived to reduce the treatment costs to the minimum. Therefore a representative and timely determination of on-line moisture content becomes vital for control set points and timely feedback. Reliable sensors have long been on the æwish listÆ of mineral processors since the problem has always been that you can only control what you can measure, (Konigsmann, 1990). Today, the task of moisture determination is still done by the classical technique of loss in weight utilising uncontrolled procedures. These same methods were introduced in the earliest base metal concentrators. Generally, it is acceptable to have ore concentrate moisture content vary within a range of seven to nine percent, but controlling the moisture content below eight percent is a difficult task with a manually controlled system. Many times, delays in manually achieving reliable feedback of the moisture content results in the moisture varying from five to twelve percent before corrective actions can be made. This paper first reviews the traditional and widely available methods for determining moisture content in granular materials by applying physical principals and properties to measure moisture content. All methods are in some form affected when employed on mineral ore concentrates. This paper introduces and describes a unique and promising novel on-line moisture sensor employed for mineral processing de-watering applications, which not only automates the tedious tasks but also results in reliable moisture feedback that can be used in the optimisation of the de-watering process equipment such as pressure or vacuum filters and fuel-fired driers. Finally, two measurement applications will be presented to indicate the usefulness and to summarise the measurement requirements for the proposed method of employing drag force and mechanical properties of the material itself to determine the moisture content. The commercial model of the equipment is described with the features and benefits to the users summarised.

Jan 1, 2003

By W. B. Dingle

"IntroductionMANY PAPERS presented on developments in the Canadian Petroleum Industry •during the past few years have commenced with this general sentence: ""The past year has been a record •one for the oil industry in Canada, with new records being set in nearly all phases •of exploration and development ,activity"". This sentence applies equally well to 1951. It is not possible to outline all the details of the broken records in exploration, development, and production but general comparisons can be made. There are several significant developments that have stolen the spotlight during 1951, some of which were foreseen in 1950 and some which were not. Among the high-lights were the following:(1) The greatly •expanded activity in the search for gas, which was touched off by the new Alberta regulations covering gas leases and reservations.(2) The discovery of commercial oil production in the Williston basin of North Dakota and Manitoba, which will have far reaching effects on Canadian oil.(3) The greatly increased activity in northern Alberta, northwestern British Columbia, the southern Northwest Territories, Saskatchewan, and Manitoba.(4) The new discoveries in the general central Alberta area.(5) The granting •of a permit for an oil pipeline to the Pacific coast.(6) The arrival of Western Canadian crude in central Ontario.(7) The number of new refineries completed, commenced, or proposed.(8) The present •and proposed expansion in the petrochemical industry.Most of the remarks made on various exploration and development •activities will refer to Western Canada operations, primarily because the greatest •activity and the most significant developments have been there. Eastern Canada exploration and development operations were at a slightly higher level than in 1950."

Jan 1, 1952

The 28th annual American Mining Hall of Fame Awards Banquet and fundraiser sponsored by the Mining Foundation of the Southwest will be held at the Marriott University Park Hotel, Tucson, AZ on Saturday, Dec. 4, 2010. The Mining Foundation of the Southwest is a nonprofit organization whose objectives are public education about the mineral industries, and recognition of outstanding accomplishments in and contributions to the fields of mineral and fuel resources. Funds are being raised to the support the foundation?s educational programs. Among these is the Educational Outreach Program operated jointly by the foundation and the Arizona Department of Mines and Mineral Resources.

Jan 1, 2010

By Paul D. Kovscek, Charles D. Taylor, Edward D. Thimons

When blowing ventilation is used on a mining section, a machine-mounted scrubber is often required to maintain face dust levels below 2 mg/m3. Operation of the scrubber also affects airflow patterns at the face and the dilution of liberated methane. Reductions in scrubber flow can result in increased methane concentrations. During mining, loading of the scrubber filter with dust is likely to reduce airflow. Detecting changes in scrubber flow is difficult, especially with extended cutting, because the machine must be operated from a remote location. Tests were conducted to demonstrate how scrubber airflow could be continuously monitored at a remote location. Three variables, static pressure at the fan inlet, differential pressure across the scrubber filter, and scrubber fan motor current, were continuously monitored while the scrubber filter was incrementally loaded to reduce air flow. The results show that monitoring each variable provided a way for estimating scrubber flow.

Jan 1, 1995

By Richard H. Sibson

Changes in seismic style along the San Andreas fault system appear to correlate with strike-parallel variations in regional heat flow. Large earthquake ruptures are associated with colder segments of the fault zone, while comparatively high levels of microearthquake activity and small to moderate shocks occur along the hotter segments, often in association with aseismic creep. Such behavior is consistent with geotherm and strain rate dependent profiles of shear resistance versus depth, constructed for quartz-bearing rocks. These profiles suggest that the transition from frictional to quasi-plastic behavior with depth should increase by a few kilometers passing from the hotter to the colder portions of the fault zone, giving rise to long-wavelength concentrations of distortional strain energy near the base of the seismogenic zone in the cold segments. Some support for this hypothesis comes from the observed deepening of microseismic activity passing northwest and southeast from the central Californian active region to the currently locked, ~400 Ian segments of the San Andreas fault that ruptured in 1906 and 1857.

Jan 1, 1982

The Library of the above-named Societies is open from 9, A.M. to 10 P.M. on all week-days, except holidays, from September 1 to June 30, and from 9 A.M. to 6 P.M. during July and August. The Library contains about 55,000 volumes, including sets of technical periodicals and the publications of scientific and technical societies. Members of the Institute, with few exceptions, are forced to spend a portion of their time in localities isolated from sources of information. To these the Library can render valuable service through correspondence; letters requesting information will receive special, attention. The Library is prepared to furnish references and copies of articles on mining and metallurgical subjects; to determine the existence of mining-maps, and to furnish general information as to the geology and mineral resources of all countries. All communications should be made as definite as possible so that, the information received may be what is desired and not include collateral matter which may not be of interest. The time spent in searching for such collateral matter will be saved, and the information will be sent more promptly and in more usable shape. The members of the Institute can be of service to the Library y forwarding copies of mining reports, maps privately issued, and similar material, which will be classified; indexed, and made availableto other members. Suggestions for additions to the Library, either y purchase or personal solicitation as gifts, will be welcomed. It is hoped that members while in the city will use the Library freely, and assurance is given that most careful service will be rendered to them.

Jan 8, 1914

By Wilbur I. Duvall

This report presents experimental data on crater formation in four rock types. From an analysis of these data a general theory of rock breakage by explosives is deduced. This theory accounts for most of the rock breakage and other phenomena that occur when a concentrated charge is detonated in a drill hole near a free surface. From instrumented crater tests and high-speed motion pictures of the explosions, various experimental checks on the deduced theory of rock breakage are made. The general mechanism of rock breakage by explosives as described in this report is outlined briefly below. The detonation of the explosive charge creates a high gas pressure in the charge hole, which in turn generates a compressive strain pulse in the surrounding rock. This compressive strain pulse travels outward in all directions from the charge hole. Near the charge hole the amplitude of this strain pulse is sufficient to cause crushing of the rock. However, as the strain pulse travels outward its amplitude decays rapidly until no further crushing of the rock is possible. The compressive strain pulse continues to travel outward until it is reflected by a free surface. Upon reflection the compressive strain pulse becomes a tensile strain pulse. As the strength of rock in tension is much less than in compression, the reflected tensile strain pulse is able to break the rock in tension, progressing from the free surface back toward the shot point. In other words, the rock is pulled apart, not pushed apart.

Jan 1, 1957

By Margaret Armstrong, Chris Roth

One advantage of kriging is that it provides both an estimate of the block or point grade, and an indication of the local precision via the kriging variance. If one assumes that the estimation errors are normally distributed, then confidence intervals for the grades can be calculated. But in mining, grades are rarely normally distributed; in general, they are skew. This is particularly true for precious metals. In this paper we study confidence intervals for variables with non-normal distributions. Using a non linear geostatistical technique, the grades are transformed into their normally distributed equivalents. Confidence intervals are obtained for these normal variables, and back transformed to give the corresponding confidence intervals for the grades, for either points or blocks. This approach is applied to gold data from the Witwatersrand basin in South Africa.

Jan 1, 1996

By Magnus Evertsson, Rebecka Stomvall, Josefine Berntsson

"Understanding the effect of particle shape on dry rheology is considered to be an important aspect in order to replace natural sand used in concrete with manufactured sand. Crushed particles from solid rock are normally less rounded and have less equally shaped dimensions compared to natural sand. Thus, the flowability and workability of the concrete will be different. In previous research, it has been demonstrated how different crushing techniques affects the shape of the particles. In many cases it is believed that Vertical Shaft Impact (VSI) technology is a way forward to replace natural sand. To be able to study the effect of VSI at the smaller fractions (63-2000 µm) sufficient measurements methods to determine particle shape are required. Optical tools to analyze the aggregates would make it possible to study a large amount of particles at small fractions. The determination of particle shape of aggregates is challenging since the shape is highly irregular and the size span of particles are very large. This study aim to evaluate one of the available optical tools, the Camsizer, for digital imaging determination of shape and size distribution. The available default shape parameters of the Camsizer are studied to understand the meaning of the parameters and their suitability for determining the quality of manufactured sand. To evaluate the capacity to determine particle shape, tests are made with 35 different materials. The results are compared with the dry rheology measured with the standardized "flow cone" test. Dependence has been previously proven between particle shape and the mass flow rate in the cone. Three different shape parameters, aspect ratio, sphericity and symmetry, are studied with the Camsizer and the results are compared with the mass flow rates in the cone. The results indicate a strong linear relationship between the optical parameters and the flow cone test."

Jan 1, 2014

Jan 1, 1927

Jan 1, 1946

By Huafu L, Ruishi N, Hongnian Y, Qinglong Z, Yangshen S

The Dongshan terrane was first recognized in 1984 (Guo,et al., 1984, 1989) as an old continental crust block of migmatized granitic gneiss in the Southeast Coastal Hercynian-Indosinian orogen, and it was thought to have occured on Dongshan Island, which has an area of less than 100 km? Recent research work has shed much light on the geology of the Dongshan terrane.The Dongshan terrane is approximately 40-50 km wide and 380 km long, trending NE. It runs from the region of the mouth of the Ming River through Putian and Huian Counties, Amoy and Dongshan island of Fujian Province to Nanao island of Guangdong Province, bordering the southern segment of the coastal region and coastal islands of Fujian and eastern tip of Guangdong Province. The Dongshan terrane is divided from the Zhejian-Fujian Mesozoic Volcanic Mountain Chains by the Changle-Shaoan fractural zone, and its eastern boundary is covered under water in the Taiwan Straits.

Jan 1, 1990

By C. Larsen, I. Orford, L. Strah, M. Renaud, P. Radziszewski

"An AG/SAG mill was commissioned at the Brunswick mine concentrator in October 1998. This paper discusses the original shell top hat liner design for the bi-directional AG/SAG mill, observed liner wear, subsequent liner design modifications, and benefits.The original liners were chrome-moly steel Norsteel with rubber grates and rubber-lined pulp lifters. The design was based on experiences of other AG/SAG mills and recommendations by the liner supplier, Norcast. Liner design modifications were made in an iterative fashion after observing the wear rate profile of the liners; over ten liner sets were implemented. Shell liner design improvements were supported by a design of experiments approach in conjunction with discrete element method (DEM) charge motion simulations. Design optimization took into account lining costs and impacts on operating performance. The team approach to the liner design improvements process is described with emphasis on the application of the design of experiments. The liner wear history and mill operating performance are presented."

Jan 1, 2005

By Robert R. Perron

The U.S. Bureau of Mines is engaged in many diverse programs fur improving mine safety. One area of interest to the Bureau is new and improved means for minimizing the hazards of accidental gas ignition or electrical shock should the frame of an off-track machine assume potential above ground. Various means presently used to prevent such occurences are the use of ground fault detectors for phase to ground faults in ac machines, and grounding conductors and diodes in dc machines. In a three phase ac power center, a phase to ground fault may be detected by monitoring the current in the grounding resistor which is required between the power center neutral on the load side of the power center transformer and ground. Another method for detecting a ground fault is to pass the three load conductors through a toroidal core transformer. The phase currents vectorially add up to zero if none of the phases are faulted, and hence the voltage of the transformer secondary is either zero or not zero if one of the phases is unbalanced or faulted.

Jan 1, 1976

By Hill J. R M, McDonald M. M

A prediction technique for support perfor- mance of hydraulic backfill in narrow stopes is applied to two stopes separated vertically by a sill pillar. Predicted stope wall closures and fill pressures compare favorably with field measurements taken over a period of several years at two mines in the Coeur d'Alene dis- trict. Stope wall closure and peak pillar stress can be substantially reduced by improved fill quality within a practicable range of fill and rock properties.

Jan 1, 1973

By Catalin Florin Petre, Elahe Ghasemian Langeroudi, Abdelaaziz Azizi, Éric Proulx, Caroline Olsen, Paul Blatter, Faïçal Larachi, Claude Gagnon

"The recovery of gold from ores is often accompanied by the release of other species in the leach solution. This state of affairs leads to depleted free cyanide levels in the slurry. Therefore, separation and quantification of these cyanicides and free cyanide at different stages of the cyanidation process as well as in waste solutions is crucial to provide mitigation tools by preventing leaching of deleterious metals for environmental considerations.COREM and the research group of Prof. Larachi have been working together on the control of gold passivation and cyanicides during cyanidation for several years. Previously, a first capillary electrophoresis (CE) protocol for the speciation of sulfur and cyanicides (SCN-, Cu, Fe) during cyanidation of gold complex sulfide ores was developed and validated for assessing industrial process water.The separation of zinc cyanide complexes used to be confronted with a number of difficulties due to the weak and/or undetectable cyanocomplexes in formally available CE protocols. Moreover, according to our knowledge, no direct CE protocol exists to separate free cyanide. Therefore, a new study aimed at developing a second CE protocol for the detection and quantification of cyanide complexes of zinc and nickel as well as of free cyanide in the cyanidation process water.To achieve this goal, six common carrier electrolytes such as pyridine, trimellitic acid, 4-methylbenzylamine, sodium chromate, phthalic acid and tris base were studied, using an indirect UV detection method. The best results were obtained using sodium chromate for which all ions were successfully separated and quantified. In addition, the effect of electric field strength, injection volume, electro-osmotic flow (EOF) modifier and background electrolyte (BGE) concentration were examined, while peak height, peak area and noise were considered for optimization.As a result, the new protocol is expected to complete the initial CE protocol by detecting cyanide complexes of zinc and nickel as well as free cyanide. Moreover, analytical determination of free cyanide in the presence of weak cyanide complexes achieved by the new protocol was also compared to conventional titration using silver nitrate solution. This new CE protocol will contribute to applied research and help plants to better understand and eventually control the behaviour of cyanidation circuits."

Jan 1, 2011