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By W. H. Strickland

The research reported here characterizes ultrasonic ranging sensors for autonomous navigation on underground mine mobile equipment. Because ultrasonic rangers are inexpensive, have no moving parts, have no lenses to clean, are small and unobtrusive, and can measure distances in dusty environments, they are especially sui ted to underground mi ne environments. The investigation began with laboratory tests of field of view, angle of incidence, intersensor variation, and ranging accuracy of individual rangers and a ring array of 24 sensors. The results showed the sensors have good accuracy and low variability. Additional experiments at AHAX' s Henderson mine Showed the sensors could accurately and reliably measure rib features, convex and concave corners, and drift intersections. The results showed that when used and analyzed properly, the sensor data may be used reliably for underground mobile equipment navigation.

Jan 1, 1990

By D. R. Taylor

Treatment of bentonite clay with mineral acids yields a modified clay product of high surface area and acidity which exhibits enhanced adsorptive and catalytic properties. A highly specialized segment of the clay industry based on this process has evolved into worldwide business with a capacity of about one-half million tons/yr. This paper will present data on the chemistry, mining, manufacturing and applications for acid- activated clays.

Jan 1, 1986

By Joseph O. Cook

I know this is, at best, a frustrating period for the coal mining industry. About 20,000 miners have been laid off, mostly in the Appalachian and mid-western areas, and several mines are working less than 5 days a week; however, the industry is experiencing modern growth and, at least, there is the potential for future growth. The coal industry is probably only operating at about 80 percent of its present capacity, and it is certainly capable of helping this country solve its energy problems. Growth, as a rule, does not come easy, and growth in the coal industry is no exception to this rule. Many formidable challenges have to be overcome. As we all know, mining relies very heavily on the earth sciences, which have advanced significantly in the past few years, but we are always working in a changing environment which in most cases is a hostile environment. Large quantities of material are quickly extracted and rapidly moved in, generally speaking, a very confined area. The very nature of the mining business directly and constantly impacts our environment during this period in which the Nation and the world has become increasingly smaller and more concerned about protecting our environment. In addition, growth brings about an expanding work force which is increasingly younger and less experienced.

Jan 1, 1980

By B. L. Bobo

To ensure the continued growth and economic viability of the Western coal industry, both in the domestic and inter- national markets, it is essential for the industry to become more creative and active in confronting the most serious obstacle in this objective; and that is, the inherently long distances which Western coal must be transported inland to reach its major markets. Figure 1 shows the 1982 coal consumption by state for those states where Western coal was consumed. (Except as noted in this paper, Western coal producing states are defined as Colorado, New Mexico, Arizona, Utah, Wyoming, Montana and North Dakota. Any exceptions used will have only an insignificant effect on the content of the paper). This figure illustrates the long distances that are required for Western coal to reach its markets. The total production for 1982 from the Western coal producing states was approximately 220 million tons, of which only 85 million tons was consumed within the boundaries of these states. The remainder was transported to markets outside the area. This map also shows, based strictly on the consumption of the states to which Western coal was shipped during 1982 and not considering other factors which are involved in the marketing of coal, the total market potential of Western coal would amount to a total of 445 million tons. This does not include export coal from the West Coast, which is now estimated to be less than 2 million tons for 1983. In 1980, it had been estimated that by 1985 the West Coast exports would have been at least 10 million tons per year, which will not be attained.

Jan 1, 1983

By John H. Bassarear

By 1968 Cyprus Pima was milling 38,000 tpd of copper ore using a conventional flowsheet consisting of three stages of crushing rod mills and ball mills. A 15,000 tpd expansion was put on stream late in 1971 using primary crushing, semiautogenous mills, and ball mills. Identical ore is treated in both concentrators. This paper shows the weight and life of each individual liner for each crusher and each mill over a four year period from 1974-1977. Power and media consumption are shown for the same period and a comparison is made between the two reduction methods.

Jan 1, 1980

By John J. Dran

Large mining companies use a number of sophisticated analytical techniques for introducing the element of risk into the valuation of mineral reserve sites. These methods include, but are not limited to, sensitivity analysis, computer simulation, conditional probability, and portfolio theory. Such techniques enable the managements of these large companies to have an awareness of the many possible ramifications of their investment decisions. On the other hand, small mining companies and individuals in the mining business, due to limited financial and technical resources, still rely primarily on single point estimates of the value of mineral reserves. These small miners introduce the aspect of risk only through the application of an appropriate "speculative" discount rate. This paper illustrates the application of a technique for the introduction of risk into investment analysis. The method appears to be most suitable for use by small mining companies and individuals contemplating a large investment in a new mineral reserve site.

Jan 1, 1974

By D. Spitty

Mining companies often have many disparate systems and repositories of data in their organization for planning and scheduling outbound mining supply chains. To optimize ore quality, throughput, transport logistics scheduling and delivery to contract, planning teams need to model and manage the value chain accurately and achieve a consolidated, enterprise view of operational performance. Planning teams coordinate a complex series of activities to ensure production forecast accuracy. They also negotiate and execute complex contracts often with disconnected and limited visibility of production forecasts, quality, and variability with little ability to accurately market potential product specifications over longer time horizons. This market is becoming increasingly dynamic, with increasing variability and the time for planning teams to react is decreasing. This is driving the need towards using science to generate the necessary scenarios required to support the decisions made by planners on a frequent basis. Resource-to-Market is a highly flexible, user-configurable supply chain management system for the mining and metal processing industries. This provides an integrated view of the supply chain that supports the dynamic nature of planning in a mining company, embraces variability of elements across the supply chain with the ability to optimize across all the functional areas of the operation to enable optimal decision making for often competing objectives such as throughput, quality, cost, revenue and profit.

Feb 23, 2014

By J. J. Gusek

An 81 hectare (200 acre) tailings impoundment at a taconite operation in Wyoming that ceased operations in 1983 has been a source of blowing dust. The site qualified for reclamation under Wyoming's Abandoned Mine Land (AML) reclamation program. The ultimate reclamation construction included: incorporating commercially available organic amendments and fertilizers into a 300 mm (12 in) thick "cap" of a sterile clay loam cover material, lowering the water level in an adjacent flooded mine pit that was feeding uncontrolled seeps into the tailings basin, constructing a wide tailings pond spillway that allows flood control while minimizing seasonal water level fluctuations in the pond, and building rock berms and rock snow fences for wind erosion control and soil moisture preservation. Tree planting in the protective wind/snow shadows of rock berms and rock snow fences, and the plugging of a decant pipe are planned for future work.

Jan 1, 1998

By Alfred G. Hoyl

The author, in exploring a virgin area vertically in two known ore shoots requiring decline shaft sinking, drifting, crosscutting and diamond drilling, chose to use electric, electric hydraulic, and diesel rubber-tired equipment. A rebuilt hoist, and electric hydraulic shaft shovel (mucker), hydraulic sinking drills, single boom electric hydraulic jumbo, electric hydraulic LHD, and electric hydraulic diamond drill were used successfully. Slides of the equipment and its use are shown. The advantages and disadvantages of the equipment are discussed, together with costs and production.

Jan 1, 1984

The removal of tritium from tritiated water (-0.5 µCiIL) was studied by metallothermic reduction using aluminum. The influence of the three variables namely the aluminum powder amount, the NaOH concentration and the reaction time has been studied on the tritium activity reduction. The experimental results and statistical analysis showed that more than 85% of tritium can be removed from the tritiated water. Further work on the tritium recovery as well as efforts to totally decontaminate water by incorporating a cryogenic concept is currently pursued.

Jan 1, 1998

By M. J. Friedel

The U.S. Bureau of Mines (USBM) investigated the use of seismic refraction tomography (SRT) for identifying changes in pillar loading at the Foidel Creek coal mine near Steamboat Springs, CO. The inherent three-dimensional problem of directly imaging coal pillar conditions is reduced to a single plane by considering only the load transmitted from the pillar to the adjacent floor rock. Floor strata velocity tomograms (at two pillar locations) illustrate that loading conditions are non-uniform and non-unique. Also, time sequence monitoring, as the longwall face advanced, demonstrated that SRT can be used to image spatial changes in loading conditions. SRT offers the mining engineer a simple and flexible technique for evaluating pillar conditions, and thus, both present and alternative mine designs.

Jan 1, 1994

By W. Zhang

"The adsorption of collector on chalcocite has been studied in situ in aqueous solutions by applying an atomic force microscopy (AFM). The AFM images show that xanthate, such as potassium ethyl xanthate (KEX) and potassium amyl xanthate (PAX), adsorbs strongly on chalcocite mainly in the form of insoluble metal xanthate, which binds strongly with the mineral surface without being removed by flushing with ethanol alcohol. The result clearly shows that the adsorption of xanthate on chalcocite is totally different from its adsorption on chalcopyrite, during which oily dixanthogen is the main adsorption product on chalcopyrite surface. AFM images also showed that increasing solution pH to 10 doesn’t prevent the adsorption of xanthate on chalcocite much and the result confirms with the fact that chalcocite floats well in a wide pH range up to 12 with xanthate being used as a collector. INTRODUCTION In flotation, the adsorption of collector on mineral surface is vital for a successful flotation process to achieve a satisfying metal recovery. Historically, many works have been carried out to clarify the adsorption mechanism of collectors on sulfides. (Gaudin and Schuhmann, 1936, Poling and Leja, 1963; Allison et al., 1972, Fuerstenau, 1982; Leja, 1982; Woods, 1984) The adsorption of xanthate on chalcocite surface in aqueous solution also attracted the interest of many researches. Gaudin and his colleagues (Gaudin et al., 1934; Gaudin and Schuhmann, 1936) studied the solubility of potassium ethyl xanthate and its reaction products in organic solvents and firstly proposed there was initially chemisorbed xanthate (X-) on chalcocite surface followed by insoluble cuprous xanthate (CuX). Allison et al. (1972) studied the reaction products of various sulfide minerals with xanthate solutions and reported that the measured rest potential of chalcocite in 6.25×10-4 M KEX solution at pH 7 was +60 mV and the reaction product of PAX on chalcocite was cuprous xanthate. Mielczarski and Suoninen (1984a, 1984b) applied the XPS and studied the adsorption of potassium ethyl xanthate on cuprous sulfide. It was reported that there was a relatively rapid formation of a well-oriented monolayer of xanthate ions followed by a slow growth of disordered cuprous xanthate molecules on top of this layer. Richardson et al. (1984) carried out an electrochemical study of chalcocite flotation with the addition of ethyl xanthate. It was proposed that cuprous xanthate and possibly cupric xanthate were adsorbed hydrophobic species on chalcocite surface due to the exchange and charge transfer oxidation reactions. Leppinen et al. (1989) applied an in-situ FTIR study of ethyl xanthate adsorption on sulfide minerals under conditions of controlled potential and they concluded that, for chalcocite, there were three different potential regions of xanthate adsorption, including chemisorption, copper ethyl xanthate formation on the surface and multilayer formation."

Jan 1, 2015

By Saul J. Escalera

Mechanisms involved in the depression of the sulfides: pyrite, chalcopyrite, galena and sphalerite with potassium permanganate have been investigated. Flotation tests were conducted using potassium amyl xanthate, Z-6, and pine oil in the absence and presence of potassium permanganate at around pH = 6. 5 naturally yielded by the sulfides in the pulp. On the basis of crystal chemistry considerations, the amount of xanthate adsorbed by the sulfides depends on the amount of sulfur and metal ions present on the surface; thus, the avidity of the sulfides for xanthate should increase in the order: sphalerite C chalcopyrite 4 galena 4 pyrite, and the ease of depression response to the permanganate action should be in the same order. Depression of the sulfides in the system occurs primarily due to the removal of the collector ions by the permanganate ions to form manganese dioxide and dixanthogen according to the reaction: 3 M(RX)2 + 2 Mn04 + 4 H20 2 ? MnO2 + 3(RX-XR) + 3 M+2 8OH where M represents the metal ion, RX the xanthate ion and (RX-XR) the dixanthogen molecule. Results seem to indicate that the permanganate ions play a triple role in the system: (1) they convert xanthate ions into dixanthogen, (2) they further oxidize the mineral surface and (3) if present in excess, they may oxidize the xanthate beyond the dixanthogen stage with the formation of CO2, H20 and SO4. All sulfides, except for chalcopyrite, showed a depression response in the order predicted regardless of the order of addition of xanthate and permanganate reagents. Chalcopyrite did not depress as easily; this behavior may be due to the avidity of the colloidal MnO2 to adsorb Cu+2 ions on its surface, this would destabilize the colloid making it coalesce with the formation of a layer of precipitated MnO2 on the surface of the mineral. The presence of this layer would prevent further action of the permanganate ions on chalcopyrite.

Jan 1, 1970

By K. R. Griffin, K. D. Luxbacher, E. C. Jong

The schlieren technique describes an optical analysis method designed to enhance light distortions caused by air movement. The ability to visualize air flow has significant implications for analyzing underground mine ventilation systems, including the enhancement of surveys and models. Currently, traditional schlieren methods are impractical underground. Background-oriented schlieren (BOS) provides a solution to this problem. BOS requires two primary components, a professional quality digital camera and a schlieren background. A schlieren background is composed of a varying contrast repetitive pattern, such as black and white stripes. This background allows the camera’s sensor to capture minor light diffractions, such as those caused by air flow. Although BOS shows great potential for ventilation analysis, sensitivity is an issue. This paper seeks to validate the BOS technique for imaging flow through a regulator by comparing BOS images with traditional schlieren images. This paper also outlines initial experimental efforts used for the validation.

Jan 1, 2011

By D. B. Sikka

Porphyry type copper ± molybdenum deposits typically occur in the Phanerozoic rocks and have been well documented. During the past two decades a number of porphyry type Cu ± Mo deposits which range in age from 1055 ± 35 Ma to 2970 Ma have been identified in the Precambrian rocks of Australia, Canada, China, Finland, India, Namibia and Zambia. Kalanjkhand porphyry copper deposit M. P., India which is estimated to contain 789 million tonnes averaging 0. 83 percent Cu (millhead-grade); 0.004 percent Mo; 0.2 gm/t Au; 6 gm/t Ag and a cap of 7.532 million tonnes of oxide are averaging 0.8 percent Cu. The economic potential of the expanded copper mining milling, smelting and refining complex to be built in the future at Kalanjkhand, which is the largest porphyry copper deposit discovered to date in the Precambrian rocks of the world is presented.

Jan 1, 1992

By W. Miola

The MSHA prescribed method for the determination of quartz in airborne respirable dust samples from underground coal mines is the P-7 method, a combination of low temperature radio-frequency ashing (LTA) and infrared analysis (lR). There is no prescribed procedure for quartz analysis in bulk samples of coal and host rock. Dispersive Infrared (IR), Fourier-transform Infrared (FTIR), and X-Ray Diffraction (XRD) methods are most commonly used for quartz analysis in powders. Several aspects of the experimental procedures such as the analysis sample preparation from bulk samples, ashing techniques, scanning procedures, peak measurement location, calibration techniques, sample amounts, size consist, and data interpretation affect differently the results from each of the methods. Significant differences in analysis results from X-ray diffraction (XRD) and infrared spectroscopy (IR) on the same samples are reported. All these studies point to the need for reliable quartz analysis methods. In a recent research, a procedure for preparing bulk coal and host rock samples for quantitative quartz analysis was developed. Further the results from X-ray diffractometry and infrared spectroscopy for quartz content on identical samples were compared. Calibrations with pure and mixed standards were used to assess the influence of particle size distribution, matrix, and calibration on analysis results. In this paper, several issues with the measurement of quartz in the samples of coal, host rock, and airborne respirable dust from mines are outlined and quantified.

Jan 1, 1994

By A. Durnan

Barrick Goldstrike Mines Inc. (Goldstrike) operates a six circuit (train) pressure oxidation plant for the pretreatment of gold bearing sulfide ores. The property is located 27 miles north of Carlin, Nevada. Since the commissioning and start-up of the first circuit in 1990 until the present total plant availabilities have exceeded 90%. The discussion that follows will detail the maintenance practices employed to consistently achieve this goal.

Jan 1, 1994

By M. Galetakis

The difficulties that rise during the evaluation of multiple-layer lignite deposits come from the deposit structure (alternating lignite layers with intercalated material of varying thickness), as well as from the limitations of the applied selective mining. Thin layers of lignite and interbedded waste layers are grouped under specified assumptions regarding thickness and ash content, to form the exploitable blocks. However, in practice the decision for excavating a block is made under subjective constraints of different importance or by using uncertain data. Advances in Fuzzy Inference Systems (FIS) have provided a new approach to the evaluation of multiple-layer lignite deposits. FIS have the ability to handle imprecise or incomplete or linguistically ambiguous information and to incorporate them into decision-making processes. In the developed FIS (Mamdani type) new linguistic variables, concerning with working conditions, operators? experience and production were involved. The FIS was used for the estimation of quality characteristics and reserves of the exploitable lignite produced from Southern Field mine, Ptolemais (Greece).

Jan 1, 2005

By J. R. Heberger

"The Safety Pays in Mining web application, developed by the National Institute for Occupational Safety and Health (NIOSH) Mining Program, helps mines determine the potential costs associated with mining injuries. This web app groups injuries by type, either by the cause of the injury or by the nature of the injury. When the user selects one of over 30 common types of mining injuries, the app provides information on the distribution of costs of workers’ compensation claims for that type of injury. Based on other user inputs, Safety Pays in Mining will estimate the total costs of the selected injuries, including an estimate of additional indirect costs, the estimated impact of total injury costs on mining company profits, and provide some examples of other items (services, equipment) on which companies could spend the savings that result from the prevention of injuries. This paper reviews the Safety Pays in Mining web application by discussing the development of the app, how it is used to show the true costs of mining injuries, and how mines can benefit from using this app. INTRODUCTION Injuries on the job cause pain and suffering. They can also profoundly affect profits and daily operations. In addition to paying direct costs or increased premiums for workers’ compensation insurance, a company might need to pay overtime for other workers to fill an injured worker’s job role, cover training costs for a replacement worker, or divert administrative resources in the wake of an injury. Safety Pays in Mining is a web app that estimates the distribution of these injury costs and assesses the impact that occupational injuries have on a company’s profits. The costs of specific types of occupational injuries in mining are not readily available as mining and insurance companies don’t usually share this information. As a consequence, companies only have cost information based on previous experience with their own employees. Therefore, if a mine never experienced a finger amputation for one of its miners, it would not be aware of the possible costs associated with this type of injury. In addition, injury costs are unique in that the cost distribution is so wide — with half of the injuries in our dataset having mean costs higher than 90th percentile costs — just using the average cost of a specific injury type does not provide adequate information. Some injuries involve immensely high costs, and even though the risk of these high-cost injuries occurring is low, mines need to be aware of their potential impact on their company’s financial health."

Jan 1, 2018

By Byron R. Berger

Disseminated Au-As-Hg mineralization is localized along the Getchell Fault system at the Getchell Mine in north-central Nevada. Replacement ore bodies occur in Cambrian carbonaceous limestone and limy shale beds. Cretaceous granodiorite, dacite porphyry, and andesite porphyry dikes parallel the fault zone and are spatially associated with the mineralization. Hydrothermal alteration and mineralization occur continuously along 4-5 km of the fault system, and extend more than 1 km down-dip. Alteration consists primarily of removal of carbonate and deposition of quartz, pyrite, and carbonaceous material. Marcasite, sericite, kaolinite, calcite, barite, and fluorite are common. Gold content reaches more than 43 ppm in parts of the altered zones and averaged 9.3 ppm in the mined ore bodies. For the mineralized zones as a whole arsenic averages 0.28%, and occurs primarily as realgar, orpiment, and arsenopyrite. Mercury (22 ppm) is finely disseminated and mercury-bearing minerals are seldom recognizeable. Accessory mineralization includes antimony (100 ppm), copper (47 ppm) , lead (18 ppm) , molybdenum (10 ppm) , tungsten (16 ppm) , and zinc (50 ppm) . Geologic field studies and K-Ar dating suggest that the mineralization is related to a hydrothermal system produced by the granodiorite and related dikes.

Jan 1, 1975