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By J L. Mauk

Golden Cross is a volcanic-hosted, low-sulfidation, epithermal Au-Ag deposit in the Hauraki Goldfield. Irrespective of the rock type (andesite versus dacite), hydrothermally altered wallrocks are enriched in K, Rb, As and Sb around Au-Ag mineralised veins of the Empire vein system and stockwork. Sodium and Sr are strongly depleted around these veins, whereas Mg and Fe are locally depleted. Calcium and Si display mixed behaviour, varying from unchanged to depleted to enriched. Other elements including Al, Ti, Mn, Zr, Y, and Nb show little change or are immobile during hydrothermal alteration. Element enrichment and depletion trends are directly related to the degree of alteration and the alteration mineralogy. Addition of K and Rb and converse loss of Na and Sr in intensely altered wallrock surrounding veins corresponds to the replacement of igneous plagioclase by hydrothermal adularia. Sodium and Sr occur in moderately altered rocks on the margins or in æhard barsÆ that contain plagioclase. Locally, elevated Si concentrations and depletion of Mg adjacent to the Empire vein system reflects intense silicification of the wallrocks and the replacement of mafic minerals by quartz rather than by chlorite. The geochemical zonation patterns at Golden Cross are very similar to those at the McLaughlin deposit California, and shallow levels of the active Broadlands Ohaaki geothermal system. Therefore, determination of K, Na, Rb, Sr, and Ca enrichment and depletion patterns provides insight into alteration intensity and mineralogy that is complimentary to traditional trace element analysis of As, Sb, Hg, Au, Ag, Zn, and Pb used in the exploration of shallow level (< 500 m) epithermal Au-Ag deposits.

Jan 1, 2000

Perhaps one of the most important conferences or symposia which our Institute has conducted, was the joint Aus. LM.M./AJ.M.E. meeting held in Canberra in May 1978, with the theme International Resource Management (Woodcock, 1978).We were privileged to witness active participation in the meeting by outstanding personalities from the mining and metallurgical industries of Australia and New Zealand, the United States of America, Canada and the United Kingdom and to hear addresses on subjects of international significance to the mining and metallurgical industries.Our Institute is one concerned with professionalism.The principal objects of The Institute as described by our founders include, "promoting the arts and sciences connected with the economical production of the useful minerals and metals, and the welfare of those in the industries, by meetings for social intercourse, and the reading and discussion of professional papers, and to circulate by means of publications amongst its members and associates, the information thus obtained".Sir Maurice Mawby (1968) said in his Presidential Address to the Institite, "the most important aspect of these objects was the promotion of the arts and sciences of the mining industry".Why is it then, that a large proportion of the papers given at the meeting in Canberra dealt with world wide social aspects of the mining and metallurgical industries, rather than the technology, the arts and sciences of mining and metallurgy as principal factors in international resource management?The answer is quite simple of course, and that is that the social and political factors are the principal factors which create the demand for basic raw materials and in the long term determine the costs and prices of the commodities which our professional abilities are drawn upon to produce.

Jan 1, 1979

By Edward Walter

Rock excavation for tunneling projects occurs on a regular basis in the Cleveland area. These tunnels are being constructed to increase the capacity of the sanitary sewer system. Controlled blasting must be performed to remove rock in a number of phases of the project. The rock excavation for construction of a junction chamber is just one case where blasting is the safest and most efficient method available.

Jan 1, 2001

By Maria I. De Rosa

High temperatures encountered by mine rescue teams during emergency situations may cause severe physiological strain, hindering the men from carrying out rescue and recovery missions. A prototype ice-cooling garment (ICG) was developed by the Bureau of Mines to alleviate physiological strain due to heat stress. The effectiveness of the garment was tested with acclimatized and unacclimatized subjects at a typical work rate (1,200 Btu/hr) expected during rescue operations and at various hot environments (97° to 113° F dry bulb and 80° to 89° F wet bulb). During exposures with the ice cooling garment, the subjects were able to maintain a safe deep body temperature of 100.4° F or below Without the garment, the deep body temperature rose beyond values of 100.4° F, a condition considered unsafe for continuous work in hot conditions. Both heart rate and skin temperature values were lower while wearing the ICG. Subjective observation also indicated a marked benefit by wearing the ICG.

Jan 1, 1976

Reconnaissance geochemical exploration in the vicinity of low angle detachment faults which bound the core of the Paparoa metamorphic core complex yielded Au up to 14 ppm, with 35% of greywacke, granitoid and quartz vein samples in the northern range exceeding the 0.01 ppm detection limit. Au is associated with Ag, As, Sb and Cu anomalies consistent with epithermal-type mineralisation. The Ag and Cu anomalies also distinguish this mineralisation from older, mesothermal Au deposits widespread in the Ordovician 'slate belt' greywackes, which comprise much of the upper plate of the core complex. Baryte, molybdenite, fluorite and stratiform U mineralisation in the northernPaparoa Range may also be related to hydrothermal activity along the detachment fault zones.

Jan 1, 1995

By G. E. d’Aquin

Sources of sulfur have varied based on technology and societal needs. It has been mined in its elemental form for centuries. Twentieth century technology brought thermal mining (Frasch, 1894) to the forefront of sulfur extraction. Then, by the 1980s, petroleum processing generated almost 40 percent of the 50 Mt (55million st) of sulfur in all forms (SAF) produced in the world. Metals processing (the reclamation of effluent gas by various means as “sulfur in other forms,” or SOF) followed at 30 percent of all sulfur values produced and then Frasch at 22 percent. Petroleum and gas processing now generate most of the elemental sulfur produced in the world. Single Two Frasch mines remain, one each in Iraq and Poland. Conventional mining of small to insignificant volumes also survives in Russia, Latin America and Indonesia. The volume of “recovered” sulfur (the name commonly given by the industry to hydrocarbon-derived material) generated will increase faster than energy consumption as oil and gas with greater amounts of sulfur are used and environmental restrictions on the sulfur content of the fuel consumed become more stringent.

Jan 1, 2005

The National Institute for Occupational Safety and Health (NIOSH) conducted a monitoring field study to optimize the rib control plan in a room-and-pillar coal mine. The study mine is located in the Central Appalachia coal basin. Two monitoring sites were selected at different sections in the study mine. The selected sites have different overburden depths and geologies. The instrumentation plans at study sites include borehole pressure cells installed at various depths in studied pillars, rib and roof extensometers and load cells mounted on number of the rib bolts. The instrumentation results and observed geology for one of the study sites showed great potential for optimizing the rib bolt plan at that section of the mine. Therefore, a rib support optimization study was followed using numerical modeling technique. A calibrated threedimensional model was developed using the instrumentation results of the optimization section. The calibrated model was used to determine the optimum rib support for expected overburden depths and rib heights. Baseline rib bolt patterns were assumed for the optimization study. Additional rib bolts, above and beyond the baseline bolting parameters, were outlined and identified as solutions to contain the rib fracturing identified by the modeling results.

Jul 28, 2020

By R. E. Zane

[The Northwest Experiment Station of the Bureau of lines, in cooperation with the College of Mines, University of Washington, has completed a detailed investigation of the physical and chemical properties of western cokes made or used in the Pacific Northwest, as evaluated by standard methods. 4/ One of the chemical properties determined, to which more or less importance has been attached, was reactivity or combustibility. As no standardized procedure is available, it was necessary to develop a workable method for evaluating this property. The combustibility of coke is usually measured by the formation of carbon dioxide with time at a particular temperature or by the reduction of carbon dioxide to carbon monoxide. Analysis of the resulting gases commonly is required to evaluate the result. The method described in this paper is simple and direct in that the sample of coke or other carbonaceous material is weighed as it burns; the loss in weight and time is indicated by a balance and clock arrangement. Gas analyses are not rewired. Methods similar in principle have been used by Tu, Davis, and Hottel6/ and by Oshima and Fukuda7/ for determining the combustion rate of carbon and for studying the effect of ash on combustion characteristics. Both methods: are more elaborate in procedure and apparatus required than teat described here. Brief the method comprises burning a sample of coarsely grained. coke or]

Jan 1, 1940

The theme of this conference is æRediscover OtagoÆ and the conference occurs during a resurgence of economic activity in New Zealand, and in particular at a time when the Macraes Gold Project has had a significant effect on mining and business activity in Otago. The Macraes Gold Mine has implemented a Zero Accident Programme and this paper reviews some of the factors responsible for the implementation.

Jan 1, 1992

By Lewis Martin

Spokane Research Center personnel are currently conducting research on cable bolts to assess their material and support properties, to provide design criteria for roof control systems under various types of underground mining conditions, and to provide background data for computer models of cable bolt supports. Laboratory studies of cable bolts made of conventional steel cables with Garford bulbs and collars resulted in recommendations on characteristics such as embedment length, hole diameter, cable bolt diameter, and configuration of cables. A completed series of laboratory tests has determined the minimum embedment length of resin required for resin-grouted, cable bolt ground support.

Jan 1, 1996

By K. J. Liles

The Federal Bureau of Mines conducts a comprehensive test program on clay and shale at the Tuscaloosa Metallurgy Research Center. All samples are subjected to standard preliminary ceramic tests, which include firing formed briquets at temperatures ranging from 1,000° to 1,250° C to identify firing range and colors, and quick-firing to determine bloating characteristics. Materials that shop potential as structural products are further tested after either extrusion or dry-pressing. If the quick-fire test is positive, bulk samples can be fired in a rotary kiln to evaluate their potential as light- weight aggregate A number of miscellaneous tests also can be conducted if requested. These tests determine properties such as refractoriness (pyrometric cone equivalency), oil-bleaching characteristics, oil absorbency, viscosity for drilling-mud applications, sand-bonding properties for foundry usage, and pelletizing characteristics.

Jan 1, 1977

By K. Severin, B. Flanigan, P. Marion

“Plutonic-related” gold deposits in Interior and SW Alaska (Tintina Gold Belt) vary significantly in size, grade, vein/deposit morphology, depth of emplacement, distance from causative pluton and metal association. Metal associations such as Au-Bi and Au-As-(Sb-Hg) are a good empirical indicator of depth of emplacement and distance from causative pluton and have been used successfully in exploration. Results from a variety of analytical techniques also suggest a phenomenological cause for these metal associations, e.g. gold and bismuth have linked metallogenesis at high temperatures and thus are best correlated at deposits that are deep and/or close to causative intrusions.

Jan 1, 2000

Upgrading of Superfine Low-Grade Haematite Ores by Reverse Floatation Direct Reduction Low Intensity Magnetic Separation Process

Sep 13, 2010

This study explores two evolving 3D surveying technologies, photogrammetry and laser scanning, and applies them to deformation monitoring of rock faces and mine highwalls. A quantitative analysis focused on 3D coordinate determination is performed. Furthermore, a qualitative assessment directed at the practicality and viability of each system operating near a rock face or in a mining operation is undertaken to reveal one systemÆs deficiencies over the other. Two photogrammetric and four laser scanning surveys aimed at optimising accuracy and precision within a short period of data acquisition are conducted on the rock face at Organ Pipes National Park, Keilor, Victoria. The accuracy and repeatability of each survey is determined using a combination of iWitness photogrammetric, and Cyclone laser scanning software. The 3D coordinates of targets placed on the rock face are determined by triangulation and resection principles within a bundle adjustment. The coordinates determined by each system are then compared in a 3D transformation. Controlled deformation conditions are established to determine the precision to which each system can detect movement in the rock face. An object of known dimensions is placed on the rock face to simulate deformation. The relative orientation of images taken for the pre- and post-deformation photogrammetric surveys provide an overall 3D point accuracy of 1.255 mm and 1.804 mm respectively. A 3D transformation shows discrepancies of less than ¦22 mm (RMS) between the geometry of the photogrammetric and laser scanning models. Both systems are able to detect the simulated deformation to a precision of 50 mm. This work also identifies how to obtain millimetre accuracy for 3D coordinate determination of rock faces, thereby providing a quality data set for surveyors, geotechnical engineers and mine geologists. Photogrammetry is shown to be a mobile, time and cost-effective technique that is more amenable to mining operations than terrestrial laser scanning. However, both systems demonstrate that they are capable of detecting movements that may lead to failures in the rock face, and possibly endangering human life. The implications are significant for surveyors, geotechnical engineers and mine geologists working in mining operations where enhanced safety conditions, increased productivity and lower operational costs are important considerations.

Jan 1, 2009

Diverse and considerable energies are associated with mobile equipment operated and maintained on mine sites. Loss of control of these energies is a common cause of injury on mine sites and this is well recognised by the mining industry. In 2006, 4 multi-national mining companies formed the Earth Moving Equipment Safety Round Table (EMERST), with the aim of engaging collectively with the manufacturers of equipment to accelerate improvements in mining equipment design. Originally focused on surface mining equipment, and particularly haul trucks, the focus of EMESRT widened to include underground and exploration equipment. Since 2006, EMESRT has maintained a program of regular visits and other engagements with a steadily increasing number of manufacturers. The membership of EMESRT has also increased, with 15 companies being members in 2012. An initial step undertaken by the EMESRT members was the development of ?Design Philosophies? which drew of the collective experience of mining companies to identify potential unwanted events which cause equipment related injuries and illness. A technique for analysing risks associated with operation and maintenance tasks, the Operability and Maintainability Analysis Technique (OMAT), was subsequently developed and trialled. In 2011, the EMERST members resolved to propose a common form of safe design information to be requested by all members companies during procurement, and the resulting EMERST Design Evaluation for Equipment Procurement (EDEEP) process was launched at MINExpo in Las Vegas in September 2012. The outcomes of OMAT risk assessment and control activities are integrated during this process into a common ?Safe Design Information? template for communication to prospective purchasers. The aims of requesting manufacturers to follow this process are to provide equipment purchasers with a common way of assessing how well the issues in the EMESRT Design Philosophies are addressed in the equipment design; and to provide manufacturers with additional information for use during equipment design. The process involves identifying priority tasks based on frequency and the severity of the consequences of potential unwanted events identified in the EMESRT Design Philosophies; undertaking a task-based risk assessment of priority tasks in conjunction with site-based personnel; evaluating the effectiveness of control measures; and providing information about safe design features in a standardised format.

Aug 1, 2013

By J. W. Hunter, J. H. Jacobs

"Approximately 355 tons of nodules from Chamberlain; S. D., ore were processed in the 1-ton-per-day electrolytic-manganese pilot plant of the Bureau of lanes at Boulder City, Nev., in a continuous 3-month operation. The ore, ground to minus 48-mesh, was found to be amenable to leaching with acid directly or after roasting under reducing conditions in a Skinner muffled multiple-hearth furnace.Unroasted ore gave an acid-leach extraction of 84 to 88 percent of the manganese, which after neutralization showed an over-all extraction of between 81 and 85 percent of the manganese. The amount of iron extracted varied, but it was always,enough to permit the use of ammonia for neutralization.Roasted ore showed an acid-leach extraction of 89 to 91 percent of the manganese. A large amount of iron went-into solution, so that it was not economical to neutralize it entirely with ammonia. By neutralizing with calcine to a pH of 5.0 and completing -neutralization with ammonia to a pH of a.5 an over-all manganese extraction of 84 to 86 percent was obtained. The slight increase in. extraction on roasted ore probably would not justify the cost of roasting.Acid consumption averaged 1.75 pounds per pound of manganese extracted. Settling rates of the residue in leach solution were to slow to permit clarification in thickeners, but a Moore vacuum leaf filter proved to be satisfactory. Purification of raw leach solution was .accomplished readily by hydrogen sulfide with a low gas consumption. Electrolysis was normal, without difficulty, and with -current efficiency ranging between 62 and 66 percent.The use of Chamberlain modules for the production of electrolytic manganese would result in an operating cost of 0.8316 cent per pound higher than the cost of producing electrolytic manganese from Three Wids ore."

Mar 1, 1946

By Wayne C. Stewart

Freezing of high pressure air lines and pneumatic equipment has been a recurring problem in the Thompson Smelter. The particular severity during the winter of 1989-90 resulted in costly process disruptions and repairs. A process improvement team with representatives from operations, engineering and both maintenance supervision and the shop floor was established to develop solutions. Their mandate included process evaluation, design, equipment and in-plant commissioning. In 1990, upon recommendation of the team, we installed three Refrigerant/Desiccant air dryers with a total capacity of 20,000 S.C.F.M. to service the Smelter. This paper discusses processes and process improvements associated with this installation.

Jan 1, 1993

By R. E. Barbosa

Seepage forces generated during tunnel excavation affect the ground response and may cause severe instability problems, including total ground collapse and flooding into the tunnel. This paper presents a new closed-form analytical solution, for stresses and displacements around a cylindrical tunnel excavated in a porous water-bearing elasto-plastic material, which includes the effects of seepage forces. The analysis is carried out in terms of effective stresses and pore water pressures. The solution shows that seepage forces may have a major effect on the effective stresses around the tunnel, on the extent of the plastic zone, on the radial displacements, and on the tunnel support requirements. The conditions for development of a ?flowing ground? condition at the tunnel face have been identified. The paper presents a procedure for the hydromechanical ground-support interaction analysis, to determine the excavation induced inflow and the pressures acting on the lining, throughout the progressive driving of the tunnel, including the effective pressures exerted by the ground and the pressures generated by the water.

May 1, 2009

By A. S. Murphy, E. V. Manlapig, C. Green, J. W. Parkinson

Historically in Australia and the United States many coal mines deposited raw wash plant fines into large slurry impoundments. At the time the technology and market economics did not exist to make it viable to recover coal from these tailings. Today better technology exist to dredge and clean the tailings and there are circumstances where government regulations and market forces have come together to make coal recovery from these old tailings impoundments economically viable. This paper discusses the processes and equipment being used in tailings impoundment reclamation operations in Australia and the United States, and discusses the economic forces driving these operations.

Jan 1, 2001

By Jinsheng Chen, S. S. Peng

The relationship between support performance parameters and parameters representative of mining and roof conditions is characterised by uncertainty, non-linearity and dependence, so the theory of artificial neural networks was selected as a basis for shield design. A computer program based on a back-propagation training algorithm was written to derive the weighting factors between inputs and outputs from field data; once these had been established two mathematical models were developed to describe the relationship. Back-calculation of field data indicates that the results generated from the neural network models are much more accurate than those derived by traditional methods and can be used with a higher level of confidence. The support density, possible yield frequency of face supports and interval of periodic roof weighting under specific mining and roof conditions can be determined by application of the models

Jun 21, 1905