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By Stephen V. Thompson

Within recent years portable seismic refraction units have found their place in the industry for shallow investigations, Completely portable, relatively inexpensive and of proven accuracy, the portable refraction seismograph is an electronic tool in an electronic age. The age of electronic instrumentation has seen the development of seismic reflection and refraction equipment for deep exploration, especially in the petroleum industry. Large, expensive units, normally truck-mounted and utilizing explosives, are being used successfully for this type of sub- surface investigation. The portable seismograph utilizes the same theory for shallow work as that applied to deep refraction seismology.

Jan 1, 1964

By George B. Griswold

The two most stringent parameters for in place fracturing of rock are the lack of any initial void space in the rock which to expand into and the ability to gain access only through drill holes. These two restrictions have proven so severe that as of today the only proven techniques for efficient fracturing are the contained nuclear detonation and hydrofracing. Both of these methods have highly developed technologies for their application. Hydrofracing has been a standard oil field practice for two decades, and the experience gained from a couple hundred underground nuclear detonations has resulted in a thorough understanding of the phenomenology of cavity and chimney formation. What is still lacking is a practical method to create a suit- able degree of fracturing for those ore bodies which do not meet the application criteria for either the nuclear explosion or hydrofracing. Nuclear applications must be restricted to thick ore deposits so as to take advantage of chimney collapse height--preferable in excess of 200 feet thick. Other requirements such as ground shock, containment, and radioactive contamination further reduce the number of sites that prudently can be selected.

Jan 1, 1969

By J. A. Porter

This paper uses project examples, primarily associated with large iron ore mines in Brazil, to demonstrate opportunities for the mining industry to go beyond traditional compliance and impact mitigation to proactively operate within the ethics of environmental and economic sustainability.

Jan 1, 1994

By Scott Donald, Barry Esford

Cameco Corp. operates uranium mills and tailings management facilities at its Key Lake and Rabbit Lake operations in Northern Saskatchewan, Canada. Development at both mine sites began in the 1970s, with initial tailings deposition occurring within above-ground impoundments, which was common for these facilities at the time. As open pits became available at each site, and mining continued at other orebodies in the area, tailings management shifted to in-pit facilities to meet stakeholder expectations and improve the long-term security and environmental performance of tailings management at these facilities. The in-pit facility at Rabbit Lake (receiving tailings since 1984; Fig. 1), was one of the first (if not the first) engineered in-pit tailings facilities in the world and adopted a full pervious surround design concept with subaerial deposition. Under this concept, permeable sand and coarse rock are placed at the base of the pit, around its perimeter, as well as overlying the tailings at closure to promote regional groundwater flow bypassing the lower-permeability tailings. In contrast, at Key Lake, the in-pit facility (receiving tailings since 1996) adopted a partial pervious surround design concept. Under this concept, permeable materials were again placed at the base of the pit, and partway up the side walls; although for the upper portion of the tailings, the material is placed directly against the natural geologic materials. In the Key Lake case, the natural geologic environment provided the required bypassing of the tailings deposit to achieve the desired environmental performance while the base drain again facilitated pumping during operations to achieve consolidation objectives (Fig. 2). In both the initial design of the facilities, and through more than several decades of operation, it is clear that although in-pit tailings facilities provide common benefits with respect to long-term geotechnical stability, it is critical that their design approach take into consideration site-specific conditions

Jul 1, 2025

By JIAQI JIN, Chen-Luh Lin, Amanda N. Erskine, Jan D. Miller, Shijie Wang

The liberation and exposure of valuable mineral grains in ore particles are of significant importance in understanding the efficiency of flotation separations. A flotation feed sample from the Kensington concentrator was scanned by micro Xray computed tomography (micro-XCT), to determine the liberation and exposure of auriferous pyrite grains. The analysis results suggest a satisfying extent of liberation for particle sizes smaller than 212 μm. Theoretical flotation recovery of pyrite for selected particle size fractions was predicted from the three-dimensional liberation and exposure analysis. The plant flotation tail was also characterized by micro-XCT to identify liberated and partially liberated pyrite particles that might not be collected into the concentrate. However, liberation analysis of the tail sample revealed that the majority of liberated pyrite was recovered in the plant flotation circuit. Trainable Weka, a machine learning segmentation approach, was compared with the Watershed thresholding segmentation for the 106 × 45 μm particle size fraction scanned at a voxel size of 1.85 μm. Improved segmentation of small particles was found using the machine learning method.

Mar 1, 2024

By R. M. Von Storch

Most coal mining areas of the Western United States are characterized either by thick beds, steep pitches or heavy cover. Individually, each of these may present inherent safety hazards that influence miring. When all are met at one location, the combined effect is to make the safe operation of the mining property a challenge to management. These combined, conditions are met in most coal mines in southeastern Utah including those of the United States Steel Corporation. This coal bed measures up to 16 feet in thickness, the pitch is as much as 25% and mining is under a cover approaching 2, 000 feet. The Sunnyside coal bed is found in the Book Cliff Mountains, a great escarpment extending from west of Castle Gate, Utah, some 180 miles to Grand Junction, Colorado. West of Green River, Utah, the Book Cliffs swing sharply to the north because of the domelike uplift of the San Rafael Swell to the southwest..It is in this northerly extension of the Book Cliffs that the Sunnyside coal in the Blackhawk Formation of the Mesa Verde Group, Upper Cretaceous Age is found. The strata are transected by numerous faults with from a few inches to as much as a hundred feet of displacement. All of these faults have had some effect on the mining operation, either in roof control or, in the case of major faulting, the pattern of mine development.

Jan 1, 1967

By B. Devulapalli

A mathematical model of the industrial hydrocyclone based on fluid dynamics is a better alternative to the currently existing empirical models. The swirling-flow velocities are determined by solving the Navier-Stokes equations with an appropriate turbulence model. The solution of the momentum-balance equations yields the flow field inside the hydrocyclone which determines the particle trajectories, and subsequently the classification curve. The essence of the model is that the physical dimensions of the hydrocyclone and the slurry characteristics can be incorporated, and the influence of these parameters reflects on the flow predictions. The predicted tangential and axial velocities in a 250-mm hydrocyclone are in good agreement with the laser-Doppler velocimetry measurements. Finally, the predicted classification curves show good agreement with experimental data measured on a KREBS Dl0B hydrocyclone.

Jan 1, 1993

This United States Bureau of Mines study is based on a review of U.S. mine fire accidents that occurred from 1970 through 1989. Information on these accidents was obtained through investigative reports written by Mine Safety and Health Administration personnel. For this study, 260 mine fire accident reports were examined. A previous Bureau research effort established that fires causing fatalities were more likely to occur in haulage entries than at any other underground location. This study has found that the most prolific source of haulage entry fires was the inadvertent grounding of trolley wires. The largest segment (15 out of 40 trolley wire fires) resulted from not maintaining adequate clearance between the trolley wire and the vehicle. Several novel fire prevention and control ideas have evolved in response to frequently occurring fire-related problems. These included; discriminating power isolation devices, wire cutting devices, more accessible fire extinguishers, vehicle overcurrent protection, and vehicle fire suppression.

Jan 1, 1994

By Oren Tranbarger

The ability to sense or detect the coal/non-coal interface during mining can provide numerous advantages for improving net coal recovery and quality, for increasing productivity, and for mining coal which would otherwise be ignored. This is particularly true when considering multiple, pitching, and thin coal seams. This paper discusses the application of coal interface sensing and examines several potential coal interface sensing techniques with respect to state-of- the-art, design, performance, and cost criteria. Four interface boundaries are considered: the roof, the floor, the rib, and the forward region.

Jan 1, 1982

By R. R. Klimpel

The use of froth flotation as a means of separating and upgrading sulfide mineral concentrates is standard industrial practice throughout the world. Froth flotation is also widely recognized to be a very complex system having highly interactive and often self-compensating factors at work. Several summary articles have been recently published which discuss at length some of the important practical aspects of optimizing the use of existing commercial flotation reagents. Klimpel (1987). Klimpel and Hansen (1987a), Klimpel and Hansen (1987b), and Klimpel (1988). It is apparent from monitoring the industrial practice of sulfide mineral flotation over the last decade that considerable progress has been made in optimizing the operating aspects of flotation. For example, the availability of improved instrumentation and related computer devices, modified mechanical flotation cell designs, better reagent dosage control leading to less reagent usage per ton of ore, blending of feed ores, more attention to coarse and fine particle flotations, etc., are all examples of this progress.

Jan 1, 1988

By J. Scott McDougall, J. Herman P. Eng. Vanderlaag

An underground mine fire can seriously threaten the lives of all personnel in the mine. This fact makes fire emergency planning a high priority in the mining industry. The optimum warning alarm must be fast and able to reach all miners, regardless of their location or work activity. Current means of fire warning are varied, and include such methods as stench, telephones, and word-of-mouth (messengers). Unfortunately, none of these methods are entirely satisfactory. A novel fire warning alarm which enables instantaneous warning of all underground personnel, the Canary Nine Messenger System, has been developed by VLF Magnetic Systems Inc. in conjunction with Noranda Technology Centre and the U.S. Department of the Interior - Bureau of Nines. The warning is sent by an electromagnetic signal which penetrates through mine rock to receivers housed in the battery packs which also power each miner's cap lamp. A loud buzzer in the integrated battery/receiver unit and the flashing of the cap lamp alerts miners to incoming messages. Testing of prototype equipment has demonstrated that the transmitted signal is capable of penetrating through over a mile of mine rock and activating the receiver. This report describes the theoretical basis for through-the-rock ultra-low frequency electromagnetic transmission, and the design of recently available transmitter and receivers.

Jan 1, 1995

By Atmesh K. Sinha

The demand for thermal coal both nationally and internationally is projected to increase rapidly. The marketability of high ETU thermal coal produced in the USA is, however, limited by its high sulfur content. Fortunately, over 70 percent of the sulfur exists in pyritic form. The research conducted at Southern Illinois University indicates that over 90 percent of the pyrite can be removed by simple devices such as concentrating tables, cyclones, or froth flotation cells and the desulfurized coal can be blended with low sulfur western coal to produce EPA compliance coal. Thus, both the low BTU western coal and the high sulfur midwestern coal can be rendered competitive in the utility markets, here and abroad due to improved utilization.

Jan 1, 1983

By W. Blake, J. K. Whyatt, B. G. White

In situ stress on the scale of a tunnel or mine may be distorted by geologic structures. The resulting variations in in situ stress have a direct bearing on the potential for mining-induced seismicity. New evidence collected from the Lucky Friday mine by US Bureau of Mines researchers, as well as a review of previous case studies, demonstrated that in situ stress variations affect the [spatial] distribution of mining-induced seismicity. Although overcore stress measurements have been useful in these studies. they are too expensive and, depending, on conditions, may be too difficult to collect. However, information on borehole and raise breakouts: deformation of mine openings: and patterns of seismicity, ground-control problems and rock-burst damage can be used to build a stress database. In conjunction with maps of mine structure and geology and models of rockmass behavior, this database can then be used to build a map of in situ stress variations. Such a map could provide a means of anticipating patterns of mining-induced seismicity and. Thus, could be the basis for planning appropriate measures to ameliorate rock-burst hazards.

Jan 1, 1997

By J. A. M. Cano

A brief introduction is made on the existence of sulphides in the top gas of the Midrex Shaft Furnace, giving consideration to the operation of the furnace and the liberation of sulphur as well as its consequential effects on the reduction process. The text shows a study of sulphur distribution in the pellet, emphasizing the importance of this distribution in relation to the liberation of sulphur during the reduction. A study was made to determine the sulphur compounds that exist in the pellets, showing ways of controlling the sulphur distribution and reducing its liberation?during the reduction.

Jan 1, 1989

By A. L. Hornbaker

Management of mineral resources through land-use planning procedures is not a new concept, particularly at the local level of government. Colorado may well be one of the first states, however, to vigorously attempt to evaluate on both the state-wide and regional basis, mineral resource potential and to make certain that potential for mineral resources is included as one of the primary factors considered in the local land-use decision-making process. Less than a decade ago the only consideration given to mineral resource extraction, particularly aggregate resources, was whether or not they could be produced at the particular time they were needed. This attitude has now shifted to the other extreme, not only in Colorado, but other states as well, so that other interests, especially housing projects, mountain subdivisions, recreational and wilderness areas are gaining prime consideration in land-use decisions. Ideally, in a more acceptable median position, mineral resource potential would receive definite consideration at the local level.

Jan 1, 1977

By Gary J. Goldberg

Through the early 1980s, surveying at Bingham Canyon required a great deal of repetitive and manual work. The advent of total station surveying equipment provided an opportunity to improve the speed and accuracy of surveying work while reducing manpower needs. An evaluation was made of total station systems and their ability to meet the surveying requirements of Bingham Canyon. This culminated in the purchase of a total station system as the mine reopened in 1986. The surveying department at Bingham Canyon during the early 1980s consisted of three, four-man crews using theodolites and self-leveling levels to perform the majority of the field work. Office work involved data reduction and hand plotting. Although hand-held programmable calculators were used, a great deal of time was spent manually transferring field notes to final calculations. After shutting down in early 1985, plans for start-up of mining operations in 1986 included a review of all aspects of the operation for cost and productivity improvement. Applying total station survey capabilities offered the potential to improve surveying accuracy and speed while reducing manpower needs.

Jan 1, 1990

By H. Bernatowicz

The Nucoalyzer (On-Line Nuclear Analyzer) is a new method recently made comercially available for monitoring the elemental composition of a process stream. Applications for the Nucoalyzer include grading ore on a conveyor belt before or after it has gone through primary crushing, monitoring the slurry being transported in a pipe to the concentrator, and monitoring the stream of concentrate or the tailings from the concentrator. The Nucoalyzer may also be used at the smelter to monitor elements in the feed that include copper, sulfur, iron and silicon where a uniform feed is desired. The advantage of the Nucoalyzer over most other techniques are (a) it performs the measurement directly on the process with no sampling necessary, (b) the analysis can be performed on streams of particulate and slurries, and (c) the system does not have to make contact with the material it measures. These Nucoalyzers are operating at coal fired power plants and several more are about to be placed in service. This paper discusses the principles of operation of the Nucoalyzer, our experience in the field, application of minicomputers to data reduction, and potential applications in the ferrous and non-ferrous industries.

Jan 1, 1982

By Andreas Rubo, Stephen Gos

Over the past couple of decades several endeavours have been made to develop lixiviants with the intention of replacing cyanide in gold leaching. In 1980s these endeavours were largely economically driven, due to cyanide shortages at that time. In more recent times, the driving force has shifted to occupational health and environmental considerations. It is often argued that the high acute toxicity of cyanide alone makes it worthwhile considering to replace it completely by less toxic alternative lixiviants. This has led to having to consider more criteria in the choice of any alternative lixiviants, which have often not been taken into account in the past. The intention of this paper is to review these alternative lixiviants and also review the criteria, which have ultimately led to most of these lixiviants never having found any large scale application, if they passed laboratory stage at all. It is also intended to show, that by handling and treating cyanide in a proper manner, the overall profile for the use of cyanide compared to these alternative lixiviants is very favourable. The question to really be answered is whether there is actually any chemical or process applicable to gold leaching that does not show the high toxicity potential of cyanide and that is still favourable with regard to looking at a broader spectrum of criteria and not only acute toxicity.

Jan 1, 2000

By Maria S. Adusumilli, A. Bhaskara Rao

ABSTRACT The presence of gold in lateritic crusts over mafic and ultramafic volcanogenic complexes in / and greenstohe belts, has called the attention in several parts of Brazil and also in Australia. Recent studies reveal the variety of structures and mineralogy of such crusts, and their importance in correlation with host(bed) rock types, as exploration guides, specially for greenstone belt metallogeny. The expected nature of growth of plates and/or nuggets in such crusts is under detailed study, and is considered as possibly due to dissolution and reprecipitation phenomenae of disseminated-fine-low grade ore in the host rock, in this investigation, laterite geochemistry, though incipiently discussed todate, is of fundamental importance and significance. Lateritic gold can be classified texturally as: dusty and diffused, fine, thin platy, taDular, and nuggets. Such gold is pure, and is often restricted to nodular (pisoliths, ooliths, concretions) forms or the matrix, that constitute the crusts or lateritised gravel beds which have an essentially goetnitic nature. Further this gold is recovered directly by mining the crusts or the adjoining placers with the metal derived from them. The thickness and extension of laterite crust zones is extremely variable depending oh the paleoclimatic conditions, and is conditioned to the favourable lithology and its structural expression. However, the "growth" of gold in these laterites will be conductive , without doubt, to several small scale mining activities, specially in the developing countries and regions limited to latitudes 309N and 309S.

Jan 1, 1987

By G. H. Schnakenberg Jr.

In response to the underground mining industry's growing concern with the exposure of workers to the diesel particulate matter (DPM) component of diesel exhaust, a method was developed to estimate the average workplace concentration of DPM that could be expected from using the new lower DPMemitting engines now being approved by the US Mine Safety and Health Administration (MSHA) when these new engines are equipped with state-of-the-art exhaustcontrol technology for filtering and combusting DPM. The resulting estimate uses the MSHA-reported particulate index for these engines, the prevailing rule-of-thumb ventilation rate of 150 cfm/hp and the available diesel-exhaust filter technology that has been shown to be at least 80% effective in reducing tailpipe DPM. In the estimate calculation, every engine used in an underground mine is assumed to be equipped with this control technology. Under the stated reasonable conditions, an average DPM level of 90 µg/m3 (mass) is predicted as technically feasible.

Jan 1, 2002