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The past four years since the 2008 MINExpo have been a roller coaster ride for the mining industry, with highs and lows and everything in between. One of the natural consequences of this uncertainty has been a number of significant consolidations and mergers, and this trend has trickled down into the crushing industry. And while there have been some significant changes to this sector of the mining industry, many of the big players have weathered the storm. The following is a look at some of the mineral processing companies that will be at MINExpo. McLanahan Corp. McLanahan Corp. is an example of the changes in the sector. The crushing and grinding stalwart acquired Universal Engineering, expanding its traditional focus on soft mineral crushing to hard rock crushing. At MINExpo, it will be showing off three new pieces of equipment, the LabMill Crusher, the Rocker Tooth Crusher and the Recessed Filter Press.

Jan 1, 2012

By Igor Gonzales G.

Southern Peru Copper Corporation (SPCC) has recently completed the construction of copper leaching, solvent extraction, and electrowinning facilities at their Toquepala and Cuajone plants in Southern Peru. Much of the ore for these new operations is the result of the existing mining operations that have been in existence as early as 1959. At Toquepala, pre-conditioning and bacterial dump leaching of the sulfide ore that was too low in copper content to be processed through the copper concentrator began in 1987. The Cuajone heap leach operation is treating copper oxide ore that has been stockpiled since the Cuajone concentrator began operation in 1976. The pregnant leach solutions from the dump leaching at Toquepala and the permanent pad heap at Cuajone are combined into one plant feed solution. Adjacent to the large dumps at Toquepala, a solvent extraction and electrowinning facility has been constructed. The electrowinning facility has a planned annual production rate of35,000 metric tons per year Grade A cathode copper. Initial production of the cathode copper began in November 1995.

Jan 1, 1996

By L. M. Chan, D. H. Carlson, J. H. Johnson

This paper discusses laboratory evaluation of a tailpipe emissions measurement apparatus (EMA) developed by Michigan Technological University (MTU) under contract to the Bureau of Mines. The apparatus dilutes diesel exhaust and measures the concentrations of diesel particulate matter (DPM), CO, C02, NO and NO2 at known dilution ratios. The EMA was evaluated by side-by-side comparison of its measurements with those by laboratory grade instruments. During the preliminary laboratory evaluation concentrations of DPM, CO and CO2 were measured. The concentrations of CO and CO2 measured by the EMA were usually within ±14 pct of laboratory-measured values for CO and ±20 pct for CO2. EMA DPM concentrations correlated well (r = 0.96) with the laboratory values, but were 29 pct lower on average. The CO and C02 differences were observed to be related to the method of calculating the EMAs' dilution ratio and the difference in DPM concentrations is attributed to thermophoretic and/or condensation losses related to the EMA's unheated sample probe. Preliminery analysis of data obtained with a heated sampling probe and modifications in the sampling procedures have indicated reduced variability in DPM and in the calculated dilution ratios.

Jan 1, 1991

By J. W. Leonard, C. L. Jiang, B. K. Parekh, X. H. Wang

The selective depression of pyrite from the Kentucky No. 9 coal seam was systematically examined using various kinds of inorganic and organic chemicals. Most of the organic chemicals tested showed little selectivity in pyrite depression. It was found that both orthophosphate and pyrophosphate were effective for the selective depression of coal pyrite in coal flotation using fuel oil as a collector. At substantially low concentrations of pyrophosphate, the flotation of coal pyrite was completely depressed over a wide pH range, while the coal flotation remained unaffected. The mechanism of the selective depression of pyrite by phosphates was explained with the help of thermodynamic calculations of iron-phosphate-water systems and zeta-potential measurements. It was shown that pyrophosphate reacts strongly with the iron ions of pyrite to form stable hydrophilic iron pyrophosphate complexes on pyrite surfaces.

Jan 1, 1999

By EREN KOMURLUR, ATILA GURHAN CELIK, IBRAHIM GUNES

In this study, laboratory and site studies were performed to investigate the usability of a new insertion apparatus designed for the split-set type of friction bolts. The new apparatus decreases the friction during the bolt insertion by a temporary diametric compression of the split tubes. According to the results, the new precompression apparatus was found to be advantageous in terms of the insertion practicality and prevention of the buckling problem. By allowing increases in the ratio of bolt diameter to drill-hole diameter, the new apparatus was found to supply relatively high normal stresses and friction capacity in drill holes after opening its clamping mechanism.

By Stephen P. Mulqueen

Searles Lake is an evaporite basin located near the community of Trona in northwestern San Bernardino County, CA. Searles Valley Minerals Operations Inc. (SVM), a subsidiary of Nirma Limited, currently manufactures more than 1.58 Mt/a (1.75 million stpy) of industrial minerals from natural brines produced from several lakebeds within the basin. The chemical manufacturing facilities in Searles Valley represent extremely complex operations involving solution mining and mineral extraction processes.

Jan 1, 2012

By M. Kalin, C. Steinberg

We have worked on several flooded pits from coal-mining activities in the former East Germany, as well as ones associated with hard- rock mining, including the B-zone pit discussed in the above technical paper. We found the paper to be a useful summary, but, unfortunately, it failed to give an adequate comparison of the physical limnology of the flooded pits, which is an essential component. While the title suggests that the primary focus of the review is physical limnology, it appears that it is essentially pit-lake chemistry being presented. Physical limnology requires that factors such as fetch, latitude, light penetration, relation to ground water table, methods of flooding and the physical shape of the pits be defined. These physical aspects of a pit interact with the chemical and biological processes taking place in it, all of which contribute to the character of a water body. Few of these physical aspects are presented, however. The conclusion that the authors reach suggests that meromixis may be a condition that would serve as an effective containment mechanism for contaminants in a pit. Although this may be desirable, such limnological conditions are not clearly supported by the data presented for any of the pits. These data should be summarized to facilitate comparison between the same structural units of the pit water - the epi- and metalimnion for example. The thermocline depth is a reflection of the physical forces mixing the water body, and pit dimensions affect these forces. Due to the use of different scales in Figs. 2 through 5, it is difficult to determine whether the thermocline is at the expected depth, because the fetch is not given. Moreover, the status of a water body cannot be determined unless measurements cover a period of at least one year, and depth profiles are completed to represent the entire depth of the pit. This shortcoming is most notable in the case of the Berkeley pit, where data are given for depths of only 20 and 35 m (66 and 115 ft), although the pit is reported to be 242 m (794 ft) deep. Limnological data to define the status of the pit water have to be collected at regular intervals, for the same parameters. The authors present temperature measurements for 1-m (3.3-ft) intervals, but fail to use that interval for other parameters, such as dissolved oxygen or, in some cases, for contaminant concentrations. Furthermore, the profiles for the deepest part of the pit display only part of the picture, because pits are rarely conical. Profiles can be considered to represent the status of a water body only after other stations in the pit have been monitored regularly and the consistency is determined. For example, fresh water, which can enter a pit at any depth, would interfere with the proposed meromictic conditions. Similarly, organic material at the bottom of a pit, such as the fish-waste deposited in the Gunnar pit, contribute to oxygen consumption. Oxygen depletion alone is not indicative of meromixis. It is interesting to note that the Dpit arsenic concentrations could possibly be slightly higher than the B-zone pit concentrations at depth, although this is difficult to determine accurately when a log scale is used for the D-pit and not for the B-zone pit. In our investigations, we noted arsenic removal in the B-zone pit bottom water, which was due to the formation of particles that are relegated to the newly forming sediment in the bottom of the pit. Particle-carrying contaminants form due to a combination of geochemical and biological factors and TSS contributed from erosion of the upper parts of the pit walls, whereas the settling out of particles from the water column is controlled by the physical conditions or turn over, for example. during ice cover in the B-zone pit. Although meromictic conditions for flooded pits may be desirable at decommissioning, this would depend largely on the physical conditions of the pit, because, under no circumstances, would this water be of desirable ground-water quality. Under meromictic conditions, acidity, if an environmental issue, may be reduced by microbial acid-neutralizing activity, and several heavy metals may form more or less stable sulphitic compounds. These may stay suspended in the water if conditions are such that they are not relegated to the sediments, i.e., in the absence of turnover. These processes do not take place in meromictic conditions only, but meromixis does require autochthonous and/or allochthonous organic substrate supplies, which are generated under aerobic conditions. Specific limnological (biological, chemical and physical) features of the pit lake under consideration have to be defined, such that water quality parameters can be predicted, and the objectives of the decommissioning activities, environ-

Jan 1, 1999

By J. J. Davis, C. A. J. Fletcher, M. Li, T. Jancar

This paper summarises the experimental approach to spiral modelling at the Julius Kruttschnitt Mineral Research Centre, University of Queensland, involving the use of plastic density tracers to determine partitioning performance on three models of coal spiral. This work has led to phenomenological models of the three spiral profiles most widely used in the Australian coal industry. The results from a parallel computational fluid dynamics approach to spiral modelling currently underway at the University of New South Wales are also presented. The computational simulation has been successfully applied to generic spiral geometries and is capable of predicting the fluid phase three dimensional flow fields and corresponding free surface profiles for moderate Reynolds' number and Froude numbers. Simulation predictions are compared with experimental results from a Mineral Deposits LD9 coal spiral.

Jan 1, 1995

By Ting Ren, Lihai Tan, Alex Remennikov, Xiaohan Yang, Xueqiu He

"Due to recent coal bursts in Australian coalmines, research of coal bursts has attracted intensive interest from mining researchers and engineers worldwide. Previous research has shown that the sudden drop of fractal dimension may be a precursor of catastrophic failure of rock. This paper examines the fractal characteristics of temporal-spatial distribution of acoustic emission signals released during the compression loading process of coal. This research suggests the possibility of coal burst forecasting based on acoustic emission data. The concept and calculation equation of fractal dimension is introduced in this paper. Additionally, uniaxial compression experiments of Australian coal samples are conducted, and the acoustic emission waveform and 3D location are recorded simultaneously by eight sensors Express-8 AE monitoring equipment in the loading process. The experimental results indicate that the continued slowdown of fractal dimension in time sequence can be used as a precursory signal of coal sample brittle failure. The fractal dimension of the spatial distribution of acoustic emission events decreases with the evolution of coal fracturing.INTRODUCTIONCoal bursts refer to the catastrophic failure of overstressed coal subject to the dynamic and static loads. In recent years, coal bursts have occurred in major coal mining countries and this phenomenon has attracted the research interests of international mining and geotechnical scholars. A total of five coal burst accidents happened in Australian coalmines since 2014. On October 20, 2018, a coal burst occurred at Longyun Coalmine in China’s Shandong province, which led to 21 fatalities. Unfortunately, even after decades of research, it seems neither more accurate forecasting methods nor comprehensive controlling measures put forward by researchers have solved the problems posed by coal bursts.As an instantons energy releasing process, coal bursts are always associated with energy dissipation in the forms of acoustic emission, micro seismicity, and electromagnetic radiation (Yamada, Masuda, and Mizutani, 1989). It is believed by many researchers that the frequency–magnitude relationship of micro seismicity induced by rock failure satisfies Gutenberg-Richer relationship as well (Feng et al., 2017). Hence, based on the principal and theory of earthquake source locating, micro-seismicity monitoring equipment has been adopted in many coalmines to locate seismic event origins associated with coal and rock failure in an attempt to better forecast coal and rock bursts. Although many parameters such as b value (parameter of Gutenberg and Richter’s law) (Lu et al., 2015) have been adopted as indicators of risk, the forecasting of coal bursts is still of low accuracy. The same is true with earthquake prediction, as it remains as a worldwide problem even after decades of research and practice. Acoustic emission (AE) methods are now widely adopted to detect rock failure processes under an applied stress for application predicting the abrupt failure of rock in the laboratory (Li et al., 2017). Previous studies have found that significant overlap exists between research regarding AE and micro seismicity with respect to generation process (both are concerned with the generation and propagation of elastic wave) and event origin location, as geophysical signals of both are same (Lockner, 1993). That is, the frequency–magnitude relationship and early-warning indicators found by AE research in the laboratory have a potential applicability to in-field micro seismic monitoring of coal bursts. Through experimental study, Feng and Seto found that the temporal distribution of acoustic emission counts of rock have distinct fractal structures during load-increase processes (Feng and Seto, 1999). Landis and Lucie found good correlation between fracture energy and AE energy during testing of mortar specimens as well (Landis and Lucie, 2002). Based on preliminary experimental study, many schol"

Jan 1, 2019

By David R. Maneval

In 1956 the Legislature of the Commonwealth of Pennsylvania created a "Coal Research Board" in the Department of Mines and Mineral Industries. Over the years through amendments to the original legislation, the scope of authority for research has been expanded from the narrow area of improving and increasing the utilization of coal to covering all aspects of coal technology and any other area of interest which would be of value to the coal industry. In January of 1964, the Board commenced a vigorous program using appropriated funds and funds donated by the coal industry to finance a research program devoted to seeking solutions to the mine drainage problem. A review of published literature on the treatment of mine drainage indicated that much work done up to that point in time concerned only the mechanism of mine drainage formation and theoretical chemistry. Very few applied, developmental, or engineering studies had been devoted to finding practical solutions to the problem of polluted waters being discharged from active or abandoned mines. Projects were therefore undertaken on a wide variety of more utilitarian approaches. This paper will discuss briefly some of the pollution abatement approaches which have been funded by the Coal Research Board of this State, and will describe in some detail a multistage flash evaporator treatment plant now under construction.

Jan 1, 1970

By Colin C. Harris, Jie Zheng, P. Sornasundaran

Powder surface and polymer structural changes during stirred milling have been studied as a function of grinding time, solid concentration and polymer molecular weight. It was found that specific surface area of limestone particles can be increased over 100% by using polymer additives. Particle surface and polymer structure were also found to change during grinding. Powder surface and polymer properties have been determined using Surface Tension, Fluorescence, TOC and HPLC/GPC analysis, and surface and polymer properties are correlated with operating variables and the mechanisms involved are explored. Particularly, the fragmentation of the polymer molecules was found to occur during long term grinding and this was beneficial for ultrafine grinding.

Jan 1, 1998

By Adrian Smith, Debra W. Struhsacker

13.1 INTRODUCTION Cyanide is, a generic term indicating the presence of the cyanide ion (CN-). Cyanide is a very common, naturally occurring compound produced by many biochemical reactions. Many plant species synthesize organic compounds which contain cyanide in the form of cyanogenic glycosides (Knowles, 1976). For example, trace amounts of cyanide are present in the seeds and leaves of many members of the Rosaceae (rose) family (Kingsbury, 1964). Many common items such as lettuce, maize, sweet potatoes, kidney beans, (Oke, 1969) almonds, and cigarette smoke contain cyanide. As examples, a recent chemical analysis of chocolate-covered almonds measured a total cyanide content of about two ppm (Steffen Robertson and Kirsten, 1987); and the U.S. Surgeon General (U.S. Department of Health, 1964) has shown that cigarette smoke contains up to 1,600 ppm total cyanide. The chemistry of cyanide solutions is complicated because the cyanide ion forms compounds and complexes with many elements. Some cyanide species are highly toxic whereas others are relatively inert and harmless. Molecular hydrogen cyanide (HCN) is the most toxic form of cyanide. Under most conditions, HCN exists as a gas which readily dissipates or reacts with the environment to form less toxic or nontoxic forms of cyanide. Thus HCN is an ephemeral toxin, and many naturally occurring geochemical processes reduce the HCN concentration of a heap system with time. As discussed below, free cyanide includes the two species, ionic cyanide (CN-) and molecular hydrogen cyanide. Free-cyanide toxicity in man, mammal s, and aquatic species is we1 1 documented (Doudoroff, 1976; Ecological Analysts, 1979; Towill et al., 1978). The lethal doses reported for human adults vary with the type of exposure as follows: • One to three mg/kg body weight if ingested; • One hundred to 300 ppm if inhaled; and • One hundred mg/kg of body weight if absorbed. Acute toxicity of free cyanide to freshwater invertebrates ranges from 0.028 to 2.295 mg/l, depending on species and test conditions. Generally, free-cyanide concentrations greater than 0.1 mg/l are expected to kill sensitive species in freshwater or marine environments (Doudoroff, 1976;

Jan 1, 1988

By L. E. Mylting

Modern ash handling systems exist in considerable numbers and a great deal of design and operating experience has been accumulated, It is the endeavor of this paper to point to a number of frequently recurring problems, A general appreciation of these problems will be helpful in both design and operation of systems. The light fly ash and the heavy bottom ash present different problems, and each will therefore be treated separately. Fly ash is collected in the ducting from the furnace to the stack and beneath the mechanical and electrostatic dust collectors. The greatest amount of dust is collected beneath the mechanicals and electrostatics. Hoppers are generally provided as integral parts of the collector. Suitable valves and piping are connected to these hoppers for removal of the dust. The size and shape of these hoppers are important factors in determining frequency of handling and the capacity of the system.

Jan 1, 1958

By Robert O. Vernon

Urban sprawl, and all its attendant problems, is upon us. In Florida, and much of the rest of the world, this has been intensified by a special problem - the coastal zone - a land of high-intensity urbanization localized where the sea and our citizens interact. Florida is blessed by a long coastline of beautiful beaches, indented by estuaries, lagoons and spring fed rivers. Rocky and sand covered islands invite habitation. A large and varied fauna and flora make recreation an avocation and work a pleasure. Accompanying these people are all the sustaining, and satellite industries that find the climate, labor, and commodity markets, cheap water transportation, and natural resources to be attractive. It is estimated that by the year 2008 a megalopolis will stretch down the Atlantic Seaboard from Georgia to encompass the Keys and extend along the Gulf to Alabama. This city will be fenced by the sea on one side and by the water management works, necessary to provide the water supply for this complex, on the other. What can we do about increasing the amount of water available for this population and decreasing the resultant wastes??? Rarely has there been tendered a more favorable opportunity for a coordinated planning and development project that will provide public access to beaches and multiple use of the coastal lands. Florida, as a peninsula swept by ocean breezes, having a largely indigenous water supply and only the beginning of the pollution of estuarine and coastal waters can cope with air, water and coastal dissipation and pollution, if we have a beginning at providing a constant water supply and at limiting pollution. This answer would appear to lie underground, where the porous limestones are interbedded with impervious fine-grained sediments and ground-water that circulates through these aquifers empty to the ocean and Gulf along the continental slopes.

Jan 1, 1969

By Gene M. Handel

Today the world is heavily dependent on petroleum for its energy. In the United States, over 75% of the primary energy used comes from petroleum. Other developed countries are similar. The less developed countries have a lower dependence on petroleum just as the United States did through the early 20th Century. However, these less-developed countries look upon petroleum as one of the primary energy sources for the economic growth required to improve their standard of living. So everyone considers petroleum an essential ingredient in the recipe for the good life. But there is a substantial problem with this recipe, and it is finally getting general recognition. Petroleum is a finite resource, and the world is using it up at a rapid, accelerating rate. Though it won't be exhausted for many decades, the early warnings of ultimate limits have already appeared. The suppliers of the incremental production in the Middle East have threatened to restrict increases in their production rates. And, of course, the short term embargo of four years ago clearly demonstrated the economic impact of reduced access to petroleum as a primary source of energy. World petroleum production will probably peak in. 10 to 15 years and then start declining. When that happens, economics--the allocation of scarce products (also known as the dismal science for obvious reasons)--indicates that the price of petroleum will escalate in real terms. So that's the situation today. We have a serious and growing problem facing us that could substantially alter the quality of our life over the next 25 years. Recognition that the society may face a period of lowered expectations after a long period of upward mobility will be a painful experience, but it is certainly not the moral equivalent of war. And, besides, we have time to take positive actions to avert the most serious consequences. When we consider alternate energy sources, the possibilities are almost endless: coal, oil shale, tar sands, solar, fission, fusion, wind, tides, biomass, etc. Actually, the list is endless because new possibilities are continually being proposed. Of these possibilities, coal uniquely stands out as an attractive substitute for petroleum. Coal can be, and is, burned to generate electricity and provide heat. It can be liquefied to supplement the liquid fuels from petroleum, and it can be gasified for use as synthetic natural gas. Unlike exotic alternate energy such as solar and fusion, coal has successfully been used commercially to produce synthetic fuels. But, the technology does need to be refined and modernized. Thus, coal's role is not to be "America's Ace in the Hole," but to bridge the transition from primary dependence on petroleum for energy to the utopia of renewable sources of energy. But don't be mislead by the prophets--those renewable sources of energy are going to be very, very expensive when they are invented.

Jan 1, 1978

By J. L. Kohler

The knowledge-based expert systems (KBES) is a potentially powerful technique to the mining engineer in traditional areas of mine design and operations, as well as in the emerging areas of mining automation and robotics. Since KBES is still experimental in many respects, caution must be exercised as this "high tech" tool is developed and applied to mining. The objective of this paper is to demystify expert systems by introducing the elements of KBES, discussing the strengths and weaknesses, and identifying some areas of application in mining, based on the authors' experiences.

Jan 1, 1986

By J. A. Herbst, L. B. Hales, R. Zaragoza

INTRODUCTION The Control Problem The need for automatic control in flotation plants stems from frequent and randomly occurring disturbances to the feed slurry. Typical disturbances occur in the solids feedrate, the slurry percent sol ids, and the mineralogy and flotability of the gangue and valuable minerals. In plants where semi -autogenous grinding mills (SAG) are used, feedrate changes are very large and changes in feed percent solids of 1m or more are common. Mineralogy changes between valuable minerals are common, as are changes in the host gangue rock. As these changes occur, the operator can attempt to compensate for them by making adjustments to the flotation cell levels, the dosage rates of the collectors and frothers, the pH, and in some cases the aeration rate of the cells. This problem is sometimes complicated by the fact that different sections of the flotation plant will be processing different ore types at the same time. Potential Savings with Control Flotation control brings about savings or plant improvements in two areas; the first is in improved metallurgy and the second is in reagent savings. Improved metallurgy includes increases in the average plant recovery and achieves target concentrate grade level s more consistently. Average recovery increases between 1.0 and 5.0 percentage points have been widely reported (Paakkinen, 1979; Sutherland, 1984). Reagent savings of up to 40 percent have also been reported (Hales, 1985). VARIABLES OF IMPORTANCE Control led, Manipulated, and Disturbance Variables The initial step in the analysis of the flotation control problem is identification of important variables which can affect the efficiency of separation. The efficiency of separation is represented by a group of controlled variables which can quantify the performance of a flotation circuit. This group includes variables such as grade, recovery, tonnage through- put, and circulating loads. The efficiency of separation of a flotation circuit may generally be defined by a grade recovery map, where each point on this map re- presents a set of operating conditions (see Figure 1). However, the combination of operating conditions must be set to operate close to the economic optimum. The group of operating variables which are changed in order to achieve desired circuit performance are called manipulated variables and can be classified into two

Jan 1, 1986

By R. C. Keaney

The metals industry is in complete chaos with mines being shut down, profits becoming non-existent, and continual losses to imports from other countries. Yet the raw material supplier to the glass industry has many opportunities to grow and to produce profits. Fortunately, the cost of most glass raw materials are low enough that competition from imports is not anywhere as critical as it is in the metal industries, such as copper, aluminum, lead, and others. But the glass raw material supplier must develop new products, both chemically and physically, to effectively compete in the future. The purpose of this paper is to point out generally where these opportunities exist and to suggest how they may be further developed. As the glass industry looks for energy saving materials, they look once again towards finer materials. A glass furnace is now approximately 40% efficient. Glass engineers are constantly striving for energy savings and it is well known that finer materials melt easier so that the manufacturer can operate his furnace either at lower temperatures for the same production or he can produce more material at the same temperature. The old 20 mesh sand specification is no longer sacred and as the mesh size for sand changes so do the specifications for all other raw materials used in the melting process. Highly instrumented glass furnaces can now measure quite accurately the energy needs to produce glass and can also measure the energy loss in each furnace. Glass technologists desire today a sand with a top size of 40 mesh while some would like to have the top at 60 mesh. This becomes more difficult to accomplish as a raw material supplier without .grinding. As you well know, grinding develops fines. Yet the same technologists will tell us that we can have nothing passing a 140 mesh screen. Therefore, we must develop processes which allows us to produce a finer screen size without increasing the amount of fines passing through the 140 mesh screen. To counteract this, different and changing industries are now demanding much finer products so possibly there will be markets for the fines which are currently separated out of the products. Methods that are practical and low cost must be found to develop different products with different screen specifications. What works for sand can be carried over to the other raw materials used in melting. Among the answers to finer products, of course, are pellets. Aglomeration or pelletizing has been looked at in the past and will be looked at in the future. Considerable work has been done in the glass container industry on this and must be carried out more extensively. By using aglomerated material or pellets, the glass producer will gain the benefits of melting fine materials without suffering from handling or dust problems. Pelletizing, particularly where using basic glass melting materials such as burned lime or sodium silicate, will not only produce a good pellets but will add desirable minerals to the glass batch.

Jan 1, 1986

By Tracy T. Morris

The current state of the mining community has made it imperative for operations to reduce costs and increase productivity in order to remain competitive. This has been done in Colorado with the installation of an Outokumpu flash flotation machine for the production of a gold/silver/lead concentrate.

Jan 1, 1987

By Richard A. Thomas, Liming Yuan, Lihong Zhou, James H. Rowland

Hydrogen (H2) gas released during battery charging can result in cross-interference for carbon monoxide (CO) sensors used for early fire detection and compromise the integrity of the mine atmospheric monitoring system (AMS). In this study, a series of laboratory-scale and full-scale experiments were conducted to evaluate the responses of different CO sensors to H2 gas. In the laboratory-scale experiments, constant H2 concentrations in the airflow, from 100 to 500 ppm, pass through sensors. While in the full-scale experiments, increasing H2 concentrations generated as a byproduct from charging the batteries at the battery charging station rise to the sensors under different ventilation scenarios. The H2 concentrations at the CO sensor location were measured using H2 sensors and were correlated with the CO sensor response. The effects of ventilation and sensor location on the CO sensors responses were also analyzed. The results of this study can help mining companies to select appropriate CO sensors and improve the deployment of these sensors to ensure the safeguard of underground miners.