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By Anthony T. Iannacchione

The Roof Fall Risk Index (RFRI) is a new method introduced by the National Institute for Occupational Safety and Health (NIOSH) to assist the underground stone mine operator in 1) assessing defects the mine strata and 2) rating the relative roof fall risk these defects pose. The RFRI utilizes observational techniques to identify defects in the roof strata caused by local geologic, stress, and mining conditions. Assessment values for ten defined defect categories provides the foundation for estimating a range of risk conditions between 0 and 100 that define the potential for a roof fall. This paper examines how the defect information is collected using two field verification sites and proposes methods to analyze the RFRI data. These examples provide information on how well the method replicates observed conditions and how it might be applied in practice.

Jan 1, 2006

The latest outcome of science is that aII bodies are composed of vibrating atoms or molecules. In almost all mineral bodies when changing from the gaseous or liquid condition to the solid, if the vibrating molecules are allowed free play, they arrange themselves in a symmetrical manner, and at a definite angle to each other: This angle varies with each system of crystallization. In a great many bodies this process may be brought about artificially, and the growth of the crystal watched. The most common method is to dissolve some substance in water or some other liquid, on slowly evaporating the liquid, the substance dissolved will solidify and the molecules will arrange themselves in their particular crystalline form.The element carbon crystallizes in two forms; as graphite in the form of a short six-sided prism', and in the diamond generally as the octohedron in the cubical system of crystallization. Orystalline bodies, as a rule, have plain faces but what is remarkable in the diamond is that in a great many cases the faces are rounded. Its great beauty as a gem when cut, and the high artificial value placed upon it by fashion, as well as its value as a cutting and boring instrument-it being the hardest body in nature-has caused many attempts to be made to form it artificially. These attempts have met with fair success as a scientific experiment, but as a commercial speculation they have been a complete failure. The most noted of these experIments was carried out by Mr. Hannay, of Glasgow.Paraffin spirit with lithium was submitted td prolonged heating in strong wrought-iron tubes securely welded. In most of the experiments the tubes exploded; but in a few cases the experiments were successful, and on cutting open the tubes small crystals of diamonds were found embedded in a black mass.Despretz produced minute diamonds under the influence of a powerful electric current from coal.

By F. C. Gennari, D. M. Pasquevich

With the gradual exhaustion of natural rutile, there has been extensive research into its synthesising from lower-grade titanium minerals. The removal of Fe from pseudobrookite (Fe2TiO5) by chlorination was studied, using both isothermal and non-isothermal thermogravimetric measurements. Correlation of the results obtained from element distribution maps, scanning electron microscopy, energy-dispersive X-ray analysis and phases detected by X-ray diffraction in the chlorinated samples showed clearly two associated processes. First, the pseudobrookite particles reacted with chlorine and iron was removed selectively as FeCl3(g), leaving a solid residue rich in the TiO2 phases anatile and rutile, separated from an inner layer of unreacted pseudobrookite by a distinct interphase boundary. Second, chlorine allowed TiCl4(g) to form in the reaction bed, where it removed iron from the Fe2O3 crystals as FeCl3(g) and substituted Ti through a pseudomorphic reaction

Jun 21, 1905

By James Ridenour

This report represents the first comprehensive accounting of lode mining sites in the Loon Creek mining district, Custer County, Idaho. Thirty-five mine and prospect locations have been added to the Bureau's Mineral Industry Location Subsystem (MILS) data base as a result of initial phases of a mineral appraisal of the River of No Return Wilderness; previously known locations were field checked and the updated information added to the data base. The district's major deposits are gold-copper-silver fissure-fillings hosted by biotite schist intruded by dikes ranging in composition from rhyolite to lamprophyre. These deposits contain a trace element suite similar to Tertiary pink granites and may be related to intrusion of the nearby Casto pluton. Continued firm gold prices could stimulate the search for precious metal occurrences in this and other mining districts in central Idaho.

Jan 1, 1983

By Z. Yu

Low-rank/oxidized coals respond poorly to oil agglomeration. Emulsification of kerosene in the presence of surfactants dramatically reduces the size of the kerosene droplets. While this dramatically reduces the amount of oil that is required for efficient agglomeration (down to 0.25-0.5%), more importantly, the surfactants entirely change the electrokinetic properties of the oil droplets and thus the interaction between oil droplets and coal particles. Consequently, kerosene cationic emulsions can efficiently agglomerate oxidized coal particles. The agglomerates obtained in such a process can still be recovered by screening. Surfactants can affect fine coal filtration very profoundly when used to emulsify the oil which is utilized to agglomerate coal prior to its filtration. This sequence is much more logical than the use of flocculants - highly hydrophilic polymers - as filtration additives to aid dewatering of flotation concentrates. Although such polymers flocculate coal particles, they also render coal surfaces hydrophilic and make reduction of the cake moisture content difficult.

Jan 1, 2000

This paper reports on recent field observations on the performance of support systems under different corrosion environments in Canadian underground mines. Phenomenological data are used to gain a better understanding of the main causes of corrosion in underground metal mines. Preliminary field data collected from five metal mines have been complemented by atmospheric and water sample analysis as well as fractography and metallographic studies. This has identified dominant factors that control the corrosion of support systems. The data are analysed in order to develop a support strategy for mines operating in corrosion environments.

Jan 1, 2008

By E. J. Ripling, M. W. Toaz

Tensile tests were conducted on pure magnesium and on four commercial alloys over a variety of temperatures and strain rates. The high positive slope of the ductility vs testing temperature curves that is found over a short range of testing temperatures for these materaturerials was shown to result from the fact that the microstructure was not stable at these testing temperatures. Pure magnesium did not display a transition temperature, although its sub-room temperature ductility was low. This poor ductility resulted from a grain boundary weakness. The aluminum-bearing commercial magnesium alloys had a higher ductility than the pure magnesium. ness.Thealuminum-bearingcommercialThese alloys did exhibit a transition temperature and grain boundaries that were stronger than the grain material. Both pure magnesium and the commercial alloys began initiating cracks at strains equal to one half of their fracture strain. MAGNESIUM base alloys' enormous potential as structural materials lies in their high strength to weight ratios. At present, the high strength magnesium base alloys such as AZ-80, which will be discussed later, have about as high a tensile strength to specific gravity ratio as the highest strength wrought aluminum alloy, 75s-T6, and, of course, a much higher strength to weight ratio than structural steel. Further, since the magnesium base alloys develop their high strength to weight ratios with moderate strengths and extremely light weights, the ratio of load carrying capacity to the weight of many structures is relatively higher for the magnesium base alloys than their strength to weight ratios would indicate. This results because judicious increases in section size, such as increasing the depth of bending members or adding reinforcing ribs, can frequently increase the weight of a structure linearly while the strength and stiffness increase as the second or third power of the added weight. Strength and rigidity must be designed into lightweight structures by those techniques which establish multiaxial stress states. Consequently, strong, lightweight structures frequently also possess a greater propensity toward brittle failures. In order to insure against these catastrophic failures, an extra premium must be placed on ductility and toughness in light alloys. Current knowledge of the ductility and toughness behaviors—notched behaviors—of magnesium base alloys is limited.* Most of the magnesium base alloys * The state of present knowledge regarding the effect of testing temperature on mechanical properties has recently been summar-ized by Pritchard.' crystallize in the hexagonal system, so that they are expected to exhibit a tough and ductile to brittle transition temperature. Actually, a transition temperature behavior has been reported for commercially pure magnesium in the literature, but the characteristics of this transition temperatureh uggest that it may not be a transition in the usual meaning, but simply the onset of some thermal softening, a performance much like that which face-centered-cubic lead might exhibit slightly below room temperature. If transition temperatures do exist, such important questions as the manner in which they are affected by internal variables such as chemical composition and grain size, or the effect of external variables such as rate of straining or notch severity have never been investigated. The investigation reported upon herein was undertaken in order to define some of the mechanical behaviors of the magnesium base alloys better, to gain a better understanding of the influence of some of the above listed variables, and particularly to understand their effect on ductility and toughness better. Material and Procedure Material-—Pure magnesium and four commercial alloys were used in this investigation. The alloys were selected so that chemically they made up a series with approximately the same minor alloying

Jan 1, 1957

By L. Shevenell, L. Stillings

The Acid Drainage Technology Initiative-Metal Mining Sector (ADTI-MMS) has established a Pit Lake Committee to enhance the science and understanding for the long-term management of pit lakes. Participation in this new committee is from members of federal and state agencies, industry, and academia, including numerous individuals representing 10 states. Work has begun on a pit lake literature search and review, database, classification, and sampling and monitoring procedures document. Coordination with the International Network for Acid Prevention (INAP) has been established. Future work will include preparing a prediction and assumption verification document, a report identifying variables upon which water quality is dependent, and an applied remediation technologies document, including an evaluation of the effects of backfilling.

Jan 1, 2002

By Uusna S, Canning R. G, Goodheart B. A

The development of a process for removal of iron oxides from ilmenite is outlined whereby the Ti02 content of Western Australian ilmenites can be upgraded from 55 to approximately 90 per cent. In the first stage, the iron oxides are reduced with solid carbon (coal) to metallic iron. Experimental reductions were carried out in crucibles, a fluidized bed, and a small pilot plant rotary kiln. The reduced ilmenite was then agitated in aerated water, in the presenceof catalysts, so that the iron "rusted" away from the ilmenite grains and the precipitated iron oxide was easily separable by decantation.The influence of variables on the rates of reduction and oxidation are discussed. The oxidation rate was examined for both the physical oxygen transfer characteristics and electrochemically by reference to Pourbaix diagrams, in which redox potential is plotted against solution pH.The upgraded ilmenite is expected to be an attractive material for pigment manufacture, and the iron oxide has prospects of being a marketable by-product. The process may possibly be applied to other ores.INTRODUCTIONThere are extensive deposits of ilmenitic beach sands, Le. iron titanium oxides of the general formula FeTi03, 'occurring in the lower south-west portion of Western Australia, and although there has been considerable commercial development, local producers face keen competition on a freight-cost basis. Thus the removal of the unwanted iron oxide constituent would have the double advantage of reducing the freight differential and presenting a more attractivematerial to pigment manufacturers.

Jan 1, 1965

By Farrukh M. Mazhar, Philippe P. Martin

Electrical Vertical Sounding (EVS) profiling has proven to be a valuable tool to set the alignment and guide the design of a 17 km-long, 4.7m diameter water-conveyance tunnel in the Peruvian Andes at an altitude of 4,260 m. EVS profiling helped determine where to locate boreholes, and reduce the amount of drilling to 1,200 m of vertical and inclined boreholes. EVS profiling allowed the designer to identify and verify by drilling the existence of zones with difficult tunneling conditions that were avoided by realigning the tunnel. The rock quality was checked by drilling and a combined scheme of excavation by TBM and conventional drill and blast technique was developed for the final design.

Jan 1, 2003

By J Herrmann, J Richards, B Hutchison

An extensive trial of laser-based survey and monitoring systems at Hillgrove Resources Kanmantoo Copper Mine in the Adelaide Hills, South Australia, has proved the capabilities of the system in monitoring rock movements on open pit walls. Initially, the trial involved deploying a Maptek I-Site 8820 laser scanner and the proof-of-concept Maptek Sentry software in the Nugent Pit to monitor ductile rock movements located up to 260 m away. The system was proven to be capable of monitoring various rock movements from 1.5 tonne rockfalls up to a 40 m high toppling wall failure. Data collected from smaller rockfalls was used to help build a database for Hillgrove’s rockfall management program. As part of the trial, the laser scanner was deployed to monitor a ramp movement event, as well as the toppling failure, adjacent to an IBIS slope stability radar. Both devices monitored the slump and the slowly developing toppling movements, with similar results. Although the radar was used as the successful ‘critical alarm’ device for the toppling failure, post-failure analysis showed the laser-based system to be capable of performing a similar role in the ductile rock regime; albeit over much shorter distances than the radar capability. A second laser scanner was deployed to monitor Kanmantoo’s Emily Pit in early December 2014, where it successfully provided critical alarm warnings for a block topple event. Sentry software, which takes advantage of Maptek I-Site 3D spatial imaging technology, was first released in November 2014 to meet industry demand for a cost effective, flexible system to detect movement. Sentry has now been re-launched as a fully transportable monitoring system. Deployed in a custom trailer, the system offers a power and communications module, cellular and Wi-Fi networking and a stable bollard for the I-Site laser scanner and Sentry software. This paper will present rock wall movement data from the Sentry trial and a subsequent two years of monitoring of the open pit walls at the Kanmantoo Copper Mine, at distances out to 750m. In addition, examples of remote geological mapping and small rockfall detection, using the laser scans, will be described. The Sentry system has proven to be beneficial for the continual improvement of slope monitoring and risk management at hard rock mines. CITATION:Hutchison, B, Richards, J, Richards, J and Herrmann, J, 2018. Mine rockfall and rock wall failures – proven digital laser-based approach for monitoring slopes at the Kanmantoo Copper Mine, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 463–472 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By L. J. Olivier

The possible closure and subsequent flooding of South Deep Gold Mine?s (SD) neighbouring Randfontein Estates Limited No. 4 Shaft (REL 4) necessitated the construction of five concrete plugs in the connecting tunnels to prevent the ingress of groundwater into REL4 from flooding SD. This paper describes the proposed controlled flooding of REL 4, the planned in-service monitoring of the five plugs and the water barrier between REL 4 and South Deep Mine, and the long-term maintenance of the plugs and rock mass in the immediate vicinity of the plugs.

Jan 1, 2006

By R. W. Stahl

An award is a form of recognition given for superior performance in a special field of endeavor. Each year awards are given by the Joseph A. Holmes Safety Association and the National Safety Council to mineral industries' mines, quarries, and plants that have worked a specific number of man-hours without a lost-time injury. These awards have a dual significance in that they prove that efficiency can be attained without injury to persons. Safety awards do not result from luck or good fortune but do result from sincere desire coupled with sufficient effort and cooperation to achieve a desired goal.

Jan 1, 1963

By Jerry J. Gray

Transportation charges for mineral commodity movements in western Oregon and western Washington were determined mainly by a stratified random sample canvass of producers. Total 1965 mineral production value for this area was $53.3 million; the cost or charge to move this production from the mine to the consumer or to the point of consumption was determined to be an additional $38.7 million. Thirty seven companies were contacted as a sample out of a total population of 349; the statistically expanded sample production value deviated 3.6 percent from that obtained by the Bureau's annual canvass. The agreement between the sample results and the canvass totals demonstrated the effectiveness of the sampling method for obtaining data with a predesigned level of accuracy. For comparison, the north-central Idaho and western Montana area was studied, A random sample experiment was designed, but because of the dominance of a few major companies, a random sample technique would have required more visits to producers than if only the larger firms were contacted. Eighty-four percent of the 1966 mineral value ($198.6 million) was accounted for by interviewing 27 firms out of a total population of 199. Total transportation costs or charges for the area were $26.7 million. The significant difference observed between the relationship of minerals production value and transport charges between the two areas investigated can be attributed to the difference in the minerals produced. The western Oregon and western Washington region is a nonmetals-producing area as opposed to the predominance of metals production in the Idaho-Montana region.

Jan 1, 1968

By Karl J. C. Harries

"8.1. INTRODUCTIONThe purpose of this chapter is not to provide precedents or examples of provisions, but rather to offer some comments that may be worth considering in the negotiation or review of an agreement. These comments are not intended to be exhaustive. It must also be noted that, although the chapter is written in the context of a common law joint venture, the concepts and concerns for the most part apply equally to a corporation that is owned by only a few shareholders for the purpose of participating in the project held by the corporation.The corporation has the advantage of having much of its organization established by local corporate law, but the particular wishes of the shareholders will appear in a shareholders’ agreement. The principal differences will be surprisingly small, save for the acquisition provisions that appear in a farm-in agreement1 and the substantial portion of the joint venture agreement devoted to creating and organizing the joint venture entity. Where the joint venture agreement refers to venturers and committees, the shareholders’ agreement will refer to shareholders and the board of directors, but both will have to deal with such basic matters as decision-making, default, dispute resolution, first refusals, funding, and carrying out work on the project. For convenience, this chapter usually refers to “venturers”, which may be taken to include shareholders.Negotiations give rise to many varying circumstances and concerns, and the main asset of the negotiator is an open and flexible mind. A desired result can often be accomplished indirectly in circumstances where the other side has adopted an inflexible position on a suggested approach. As precedents and standard forms tend to focus a negotiator’s thinking, they can be counterproductive. It is after the deal has been agreed to that a precedent can be of great assistance to the draftsman.The concepts are arranged in alphabetical order for convenience, not to suggest their sequence or position in an agreement or their relative importance. An agreement should adopt a progression of subjects in what the parties consider a logical sequence to read and work with. However, experience has indicated that it is best to set out in a single article the substance of the deal (i.e. the terms relating to the farm-in and what the acquiring party has to do to acquire his interest), preferably near the beginning of an agreement. The acquisition of the interest is, after all, the first order of business. The joint venture provisions will then follow in a reasonable sequence. It is also worthwhile to devote a single article to any special provisions that may apply during the earn-in period. For example, it may be provided that, although all work is to be done by the acquiring party as operator (with the duty of care, liability, and reporting requirements as set out in the joint venture sections of the agreement), but during the acquisition period, the acquiring party, acting as operator, may be at liberty to do such work as he wishes, without the need for any committee or other approvals, and committee meetings may be suspended.2An agreement is divided into paragraphs and articles to make it easier for the parties to read and understand, and to assist a party in finding “that provision” when the need arises. A comprehensive table of contents will also assist the parties who must work under an agreement. An added benefit of a table of contents is that in preparing it, the draftsman sees the overall structure of the agreement and will often catch and correct flaws."

Jan 1, 2003

By Manqiu Xu, Andrew Lee, Frederick D. Ford, Cara Wercholaz

"Platinum-group minerals (PGM) typically occur in such low concentrations that quantitative mineralogical evaluation is difficult or impossible. The FEI MLA system used by Vale Base Metals Technology Development has been successfully employed to produce large PGM data sets that are statistically robust. The MLA Sparse Phase Liberation mapping routine produces false colored images that accurately document mineral textures, including intergrowths between various platinum group minerals and between PGMs and other tellurides and sulfides. MLA PGM search results can be used in conjunction with mineral chemistry to calculate platinumgroup element distribution to minerals and the MLA PGM images can be used to produce model grade-recovery curves.INTRODUCTIONThe platinum-group minerals (PGM) found in Sudbury area deposits have been extensively catalogued and reviewed by many authors including, but not limited to: Farrow and Lightfoot (2002), Cabri and Laflamme (1984; 1976) and Cabri (1981). The PGM list currently used has 12 minerals summarized in Table 1. As noted by Farrow and Lightfoot (2002), platinum-group minerals in Sudbury are dominated by tellurides, bismuth-tellurides and arsenides, with an absence of platinum-group element (PGE) sulphides or ferro-platinum alloys such as tetraferroplatinum - PtFe."

Jan 1, 2011

By M. D. Budeba

Determining the efficiency of a surface coal mine operation is an essential activity, which can help in deciding on the optimal use of input resources, including effective capital allocation, in generating a desired quantity of coal of a specific quality. Mines operate today in challenging conditions, with diminishing reserves of high-quality coal, remote location of new coal deposits, infrastructure problems, environmental legislation, and the effects of climate. All these have an impact on the performance of a mine. Given such challenges, a company has to be technically efficient compared to other existing coal producers in order to generate profits. It can use the measurement of its efficiency to evaluate its productivity, benchmarking this against the best-performing mines and determining optimal variables in order to minimize slack and achieve the desired outputs. This paper discusses the use of Data Envelopment Analysis (DEA) in evaluating the efficiency of a surface coal mine supply chain for the coal export market. The supply chain is considered to be composed of subprocesses that are modelled as a multistage system. Numeric examples will be used to illustrate the application of DEA.

Jan 1, 2014

By Peng Jiahong

With ultrasonics application during checking the large diameter cast-in-situ pile body, it is usualy applied the statistical method of probability and PSD. This paper presents a converse probabilistic-analytical method which can identify important anomalies, both strong and weak, during interfered situation. So the inhomogeneity in concrete pile may be ellectively distinguished. In order to ensure the capacity of bed rock support layer under large diameter pile, a test-in-situ is conducted to determine the compresive strength and shear force inserting rock of the support layer, so the compresive strength and modulus value of elasticity of bed rock tested will closely tally with the actual situation.

Jan 1, 1991

By D. D. Ndenguma

This investigation compares the results from an experimental and numerical study of air flow in a scaled-down underground coal mine model. This was done in order to determine if numerical analysis can be relied upon when searching for ventilation solutions to control high concentration of coal dust and methane gas in underground coal mines. Steady state analyses were used to identify flow patterns and recirculation regions within the mining section while transient state analyses were used to determine the time taken to extract the initial air from the model. The agreement between the experimental and numerical results indicates that numerical modelling is useful in this regard. The study went further to devise a method of determining the optimum position of the jet fan that is responsible for mine-gas dilution at different stages of mining.

Jan 1, 2014

By B. Anameric, S. Kawatra

Pig iron nuggets, which have similar chemical and physical properties with blast furnace pig iron, were produced by a single step heat treatment of self reducing – fluxing dried greenballs. During this single step heat treatment the transformation of self reducing fluxing dried greenballs into pig iron nuggets did not take place instantaneously. Rather, it was composed of three transformation stages, (1) transformation of self reducing – fluxing dried greenballs into direct reduced iron (DRI), (2) transformation of DRI into transition direct reduced iron (TDRI), and (3) transformation of TDRI into pig iron nuggets. Thus, the objective of this research was to investigate these transformation mechanisms by analyzing the transformation stage products. The transformation stage products were produced at a constant furnace temperature of 1425°C and various furnace residence times. They were characterized according to their microstructure, microhardness and apparent density. The changes in the product’s physical and chemical properties with furnace residence time were utilized in understanding the transformation behavior, the chemical events that took place and the controlling mechanisms. It was determined that the transformations were dictated by the changes in the slag viscosity and wetting properties, and by carbon diffusion into metallized areas.

Jan 1, 2007