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By M. E. Volin

Reagent control for optimum concentrate yield was studied by laboratory batch flotation tests simulating the Groveland plant flotation circuit in which a rougher concentrate is cleaned twice. The reagents were a fatty acid collector, a sulphonate collector and sulphuric acid. The study included two types of flotation feed representative of the reground and deslimed tailing from the spiral concentration circuit, one when the ore mineral is predominantly specularite and the other when it is magnetite. The factorial design included three levels of fatty acid, five levels of sulphonate and five levels of H2S04, with the two types of ore in nested blocks, making up a total of 75 tests. Similarity of results and reproducibility were established in preliminary tests. The final tests were performed in random order under closely controlled conditions following the established procedure.

Jan 1, 1965

By Shiou-Chuan Sun

Notwithstanding the fact that unsaturated fatty acids are used in preference to saturated acids for most flotation purposes, information regarding their collecting properties is sketchy. Keck, Eggleston, and Lowry1 reported in 1939 that the collecting power of fatty acids on hematite decreased in the order of oleic, lauric, myristic, palmitic, and caprylic acid. Keck and Jasberg2 described in the same year that "unsaturated oleic acid with 18 carbon atoms was a better collector than saturated stearic acid" for floating magnetite. Gaudin and Cole3 stated in 1953 that the double bonds of oleic and linoleic acid were not oxidized during the flotation of fluorite, whereas the double bonds of linolenic acid were measurably altered even after one single flotation step. In August, 1953, Hukki and Vartiainen4 concluded that the collecting power of palmitic, oleic, linoleic, and linolenic acids on ilmenite, magnetite, pyrite, and rutile increased with an increasing number of double bonds in the acid molecules. This was subsequently proved to be generally true for the flotation of mapganese5, phosphate6, and magnetite7. The above cited literature indicates that, prior to the present paper, only about ten minerals were tested with pure unsaturated fatty acids as collectors.

Jan 1, 1959

By L. C. Bartel

Geologic features such as structure (faults, folds, fractures, etc.), water bearing zones, aquifers, pemeability variations, and porosity variations are important for mine planning and in situ energy recovery processes. Features important for planning a mine will be important for planning the recovery of energy by in situ processes. Various geophysical techniques might be used to obtain the necessary geologic information. In this paper, case histories will be discussed of the use of electromagnetic geophysical surveys at a potential underground coal gasification site and a potential tar sand oil recovery site to obtain pertinent geologic information. Results show that the controlled source audio- frequency magnetotelluric technique shows promise for mapping faults and natural fracture systems when there is a sufficient resistivity contrast.

Jan 1, 1982

By S. K. MONDAL, K. K. K. SINGH, S. Singh, R. K. TIWARY, S. K. Chaulya, G. C. MONDAL, R. S. Singh, T. B. SINGH

In this work, a comprehensive field study was carried out to measure the background air quality status and identify the air pollution sources from opencast mines around a heritage site in India. Air quality modeling was conducted to envisage dust concentration due to existing and closed mines in the region. The air quality modeling exercise predicted that particulate-matter levels of PM10 and PM2.5 might increase in the ranges of 3.2 to 23.1 and 2.1 to 8.9 μg/m3, respectively, due to mining activities when some of the closed mines will be operated in the region without controlled emission. The predicted total PM10 and PM2.5 at the selected receptor locations were in the ranges of 86.39 to 194.89 and 34.82 to 99.55 μg/m3, respectively. Adequate measures were suggested to control air pollution from mining activities, and an intelligent dry fog system was designed to suppress dust emission efficiently from mineral processing plants and opencast mines. The developed system has special features for facilitating eco-friendly mining.

By C. Rodriguez, T. BoBo

Comminution, being the energy intensive part of a mining operation receives much scrutiny by cost controllers, CEO’s, investors and others as the mining industry goes “back to basics” to reverse the decline in productivity which occurred during the mining super cycle. Blasting is the first and lowest cost per ton stage in the comminution value chain. The basic principle that effective blast design can optimize fragmentation from the Run of Mine (ROM) ore muck pile to improve productivity through digging, loading and crushing to grinding and increase mine site profits has been well documented. Benefits of controlling fragmentation in the blast include reduced wear on equipment, faster loading, increased truck loads while detecting oversize rocks at the muck pile can reduce the frequency of a blocked primary crusher. A second basic principle is a measure of particle size distribution (PSD) at each unit operation in the comminution cycle allows engineers to manage blast design to produce fragmentation in the ROM ore most suitable to optimize downstream unit processes to improve mine site productivity and profits. Split-Online® systems have measured PSD of rocks on conveyors from the primary crusher to the SAG mill for over 20 years. Split-Engineering partnered with various mining companies to develop Split-ShovelCam® to automatically measure fragmentation from shovels and excavators working the ROM muck pile. This paper takes the reader “Back to Basics” by discussing the use of real time fragmentation analysis at the muck pile as an important parameter to optimize energy factors required for each blast. Case studies are given. INTRODUCTION The basics of mining are: • Explore for and find economic resources of valuable minerals • Mine rocks containing valuable minerals using blasting • Crush and grind rocks to liberate valuable minerals (comminution) • Recover valuable minerals for sale Comminution is an energy intensive process which accounts for a major proportion of mine site costs. Effective blasting can improve comminution and deliver significant reductions to mine site unit costs, (CEEC, 2016). Engineers, scientists, builders and even philosophers have long promoted the phrase “measure to manage”; the premise being “you can’t improve what you don’t measure”. Blast Engineers measure fragmentation in ROM ore for feedback to manage energy input in the design of blast patterns to optimize the ROM product size for downstream operations, whether they be for ROM Leach or feed into the primary crusher.

Jan 1, 2019

By Nathaniel Arbiter

A fully-instrumented driving mechanism has been constructed to study the power, aerating and solid suspension characteristics of several laboratory flotation machines. Machines operating over normal flotation speed ranges give constant power numbers in liquid' systems indicating that they operate under fully baffled turbulent flow conditions. Owing to lack of geometrical scaling, power numbers for different sizes of cells of the same make are different. Even larger differences occur between cells of different manufactures. For a given impeller, varying the tank size did not significantly affect the power consumption. Tank geometry and baffling has a slight effect on power consumption with shrouded impellers. For a given impeller speed, suspension height decreases while power increases with increasing mass of solids in suspension. While power consumption is hardly affected by particle size and clearance between the impeller and tank bottom, the suspension height significantly increases as clearance increases and as particle size decreases. Aeration was found to affect not only power but also the suspension characteristics of the machine. For closely sized particles drastic sedimentation occurred when a critical value of the air flow number was exceeded. The critical air flow number decreased with increasing particle size. This effect was less marked with a wide particle size range. The self-aerating capacity of flotation machines increases with cell size at a given speed for the same impeller-shroud system, but decreases in the presence of frother and solids. Equations have been established for correlating all of the studied variables. Data taken from the literature were also correlated with these equations.

Jan 1, 1968

By J. S. Hastings

Tertiary calc-alkalic to alkalic rocks of the Little Rocky Mountains in north-central Montana host low-grade heap-leachable gold-silver deposits being mined by Pegasus Gold Corporation. Total production from 1884 through 1985 is estimated at 22,625 kilograms (727,414 ounces) of gold. This includes 10,774 kilograms (346,400 ounces) recovered by Pegasus between 1980 to 1986 from 20,318,000 tonnes (22,396,000 tons) of ore grading 0.960 grams of gold per tonne (0.028 ounces per ton). Silver production during this latter period was 24,556 kilograms (789,500 ounces), but reliable silver statistics prior to 1980 are not available. Ore reserves as of January 1, 1986, were estimated to be 35,380,800 tonnes (39,000,000 tons) grading 0.720 grams per tonne (0.021 ounces per ton). Present ore production is 5,533,920 tonnes (6,100,000 tons) per year at a 0.45 to 1 waste to ore strip ratio. Current annual metal production is about 2,644 and 5,288 kilograms of gold and silver respectively (85,000 and 170,000 ounces of gold and silver respectively). The Little Rockies were formed by a calc-alkalic to alkalic magma penetrating through the Precambrian basement into the overlying Paleozoic and Mesozoic sedimentary rocks. This intrusive center is Dart of the Central Montana Alkalic Province, a region comprised of twelve separate intrusive centers aligned in a northeast trending belt measuring 200 by 400 kilometers (124 x 248 miles). The ore deposits are structurally controlled epithermal systems which vary from deeper narrow veins to shallow, wide, low-grade stockworks, breccias and intensely fractured "sheeted" zones. The shallow types are now being exploited. Primary mineralization consists principally of gold and silver associated with pyrite, native gold and silver, sylvanite, calaverite, and hessite. Alteration is broadly classified as weak argillic. Pyritization, kaolinization, silicification and feldspathization are the dominant forms of alteration. Fluorite is a common hydrothermal gangue mineral.

Jan 1, 1987

By Gary English

"Tunnel safety is evolving as science, engineering and technology make advances. Applicable safety codes and standards simply do not cover all the potentials of design, construction and operation. This paper reviews a series of tunnel projects code gaps in Seattle USA that were uncovered during the design and construction of a new highway tunnel, conversion of bus tunnels to combined road and rail tunnels, new rail tunnels using TBM and NATM, conversion of a road tunnel to light rail, and retrofit of an existing road tunnel to add lanes and improve safety systems. The perspectives of the ‘fire code official’ (Authority Having Jurisdiction) on methods to identify and resolve gaps in safety code and standard regulations, while garnering the consensus of the owner, designer, and contractors are presented. Additionally, the emergency responder command perspective on safe tunnel design, tunnel rescue during construction and operational safety is explained TUNNEL SAFETY EVOLUTION The underground has become nearly the only option to provide essential transportation corridors to continue our economic growth in key global areas. Tunnels are not built on a whim. Often significant portion of a regions wealth are invested to meet current, and hopefully future transportation demands. There are more transportation tunnels being built now than at any time in the planets history. The location of these tunnels is often selected for us based upon regional demand. Most commonly under densely populated urban centers and between populations’ centers to bypass geologic conditions like mountains and water bodies. Tunnels are being built in unforgiving soils, between tectonic plates, in extremes environmental conditions and often, under the very heart of the highest density population centers on the planet. All of these locations can bring with it conditions that challenge our common assumptions about safety. These extraordinary locations and soils create risks for both those constructing the tunnel, and in design engineering to meet the ‘minimum’ requirements at the lowest costs. There is lengthy history of above ground safety. Most countries and major local jurisdictions have adopted, or created safety requirements for the construction of above ground buildings. Through decades of use, these safety requirements have evolved, changed and been expanded to cover a wide gamut of actual and potential safety risks. However, the use of the underground for tunnel transportation corridors has grown exponentially with limited attention to safety requirements."

Jan 1, 2016

By Keith Whitworth

The USSR, over the last 20 years, has continued to increase its out-put year by year and it is now almost four times what it was at the end of the Second World War. In 1975, it exceeded 700 million tons of run-oi-mine coal (all ranks) which amounts to over 20 percent of world output. This rapid progress has been due to modernization of the industry, by means of increased mechanization and automation and the development of new machines and systems for underground workings and by the expansion of open-pit workings and the development and implementation of larger earthmoving machines.

Jan 1, 1977

By Aydin Shaterpour Mamaghani, Bilgin. Nuh, Engin Dogan, Tayfun Erdogan

"Improved safety and more environmentally friendly operation are basic advantages of mechanical excavation over the drill and blast method. Raise Boring Machines (RBMs) are one of the types of these machines which have recently been increased use in Turkey. The excavated hole with RBM is more stable than other methods and has better air flow, making it ideal for ventilation shafts. This paper is a summary of the performance of a RBM in the Balya PB-Zn Mine in Turkey. Length and diameter of the ventilation shaft are 200 m and 2.4 m, respectively. The geological and geotechnical characteristics of the strata excavated in the mine are first given and later the validity of a model developed to predict the machine performance is discussed. It is believed that the results of this study and the model given to estimate the performance of the RBM will be useful guide for future applications. INTRODUCTION Raise boring technology was developed to meet the demands of the mining industry, but has also found numerous applications in tunneling or infrastructure projects for ventilation purposes. Raise boring machine uses a small diameter drill rod, around 230-350 mm to drill a pilot hole down to the required depth up to around 2000 m. Once the pilot hole has been drilled to the desired depth, a reamer of up to 9 m diameter is attached to the drill rod. The reamer is then pulled back up to the upper level, creating a round shape. Continues operation provides a faster advance rate than other methods. RBMs are suitable both in hard and soft rock. The flexibility in different angles and diameters is a great advantage compared to drill and blast excavation method. RBM creates a shaft with smooth walls which usually does not require lining. The hole is more stable than a drilled and blasted method and has better air flow, making it ideal for ventilation shafts. Raise boring is convenient method in competent rock; however several problems are faced in geological formations where geological discontinuities are dominant. Moreover, assembly and disassembly time may be long in some cases. The performance and operational parameters of the excavating machine should be predicted prior to starting the excavation operations in order to fulfill the economic requirements of the project. In the light of this fact, the main objective of this investigation is to summarize a case study on raise boring machine performance and suggest a new model based on laboratory test results. First, general description of the mine and project are provided. Then, the physical and mechanical characteristics of the samples taken from project area are discussed. In the third section, performance and operational parameters of RBM are investigated to understand the machine behavior in different rock characteristics and also to collect a useful database for further investigation. In the fourth section, a new model for performance estimation of RBM are recommended."

Jan 1, 2016

By Danny Chan, Shahram Tafazoli, Nicholas Himmelman, Edmond Chow

"While wearable technology has been garnering attention in the consumer market, enterprise and industry have just begun exploring its potential applications. Since February 2014, Motion Metrics International has been working in collaboration with Vandrico Solutions Inc. to apply wearable technology to improve productivity and safety in the mining industry.This article discusses the value proposition of using wearable technology to deliver critical notifications in mining. The advantages and disadvantages of various form factors are explored. The challenges, both specific to mining and in general to wearable technology, are defined. Finally, the concept of MetricsGear, the first wearable technology platform developed for mining by Motion Metrics International in collaboration with Vandrico Solutions Inc., is described. MetricsGear is designed to notify the user with minimal distraction to keep the user focused on his or her primary task and aware of mission-critical events. This focus and awareness allows the user to work more efficiently and safely. The mining process consists of a series of intricate stages, where certain events or conditions in one stage can have a huge impact on other stages. The notification of these critical events or conditions is vital for ensuring the overall efficiency of the mining process. Critical notifications can be classified as two types: timecritical events and contextual information. Time-critical events are situations where a timely response from a responder can have a significant impact on seizing an opportunity or mitigating cost. Some human-computer interaction (HCI) experts classify notification types based on the interruption, reaction and comprehension (IRC) framework. Time-critical events are classified to have high interruption, high reaction and low comprehension due to their urgency. The responder should have just enough information to identify the crisis and react as soon as possible (Chow, 2014). For example, when a tooth is lost during shovel operation, it is necessary to recover the missing tooth before it jams the primary crusher. The consequence of missing this critical time period is a jammed crusher that can cause the mine to be out of production until the jammed tooth is extracted (Baumann, 2013). In this case, the responder only needs to see an image to confirm if the tooth is missing and information to identify which equipment and when the tooth went missing (Fig. 1)."

Jan 1, 2014

By R. D. Williams

INTRODUCTION In a very real sense, Butte, Montana is where the copper came from that won two world wars. The price for that unrestricted mining and smelting of copper came due in 1983 when Butte was declared a Superfund site. One of the most complex remnants of this mining history is the Parrot Tailings site. The Parrot Smelter operated from 1881 to 1910 moving Upper Silver Bow Creek to the south and depositing approximately 370,000 cubic yards of waste material adjacent to Upper Silver Bow Creek. Additional mixed waste from other processing sites deposited below the Parrot Tailings at the Northside Tailings, Diggings East and Blacktail Creek Berm total approximately 224,000 cubic yards of contaminated material. As part of the Superfund remedy, EPA proposed leaving all these wastes in place. This proposal prompted a detailed criticism by several geoscientists familiar with the site. The EPA’s 2006 Record of Decision (ROD) did in fact leave these wastes in place which set the stage for a series of studies which continue to refine how best to protect extensive completed Superfund Remediation downstream of Upper Silver Bow Creek. HISTORY OF THE PARROTT MINE AND TAILINGS Placer gold was discovered in Silver Bow Creek, the headwaters of the Clark Fork River only a few miles from the Continental Divide in 1864. This discovery lead to a stampede of placer and lode claims. One of the first lode claims located was the “Parrot” lode, located in the fall of 1864. Progress for developing a mine at the Parrott was slow and it wasn’t until 1876 that one of the original locators encountered a rich vein of chalcocite. Butte had its first copper mine! The Parrott mine was patented in 1879 and by 1881 the Parrot, having lost a “t”, concentrator and smelter were built. The smelter and concentrator were an immediate success with a considerable market for processing the District’s rich copper ore. In 1885 the employees of the Parrot Smelter bought the Butte Reduction Works, another smelter. In 1885 dams were built on Silver Bow Creek to contain various tailings and related processing byproducts (Figure 1).

Jan 1, 2019

By Takayoshi Otsuka, Taher Elsamni, Ashraf Bou-Krisha, Takaya Takimoto

"INTRODUCTION Tunnel is a closed space structure and it is necessary to ensure the sufficient time and route for safe evacuation for the tunnel users in case of a tunnel fire. In order to do so, damages and collapse of the tunnel linings and the secondary disasters can be avoided. Furthermore, the road tunnel is one of important infrastructural facilities and stopping its function for a long time for a tunnel fire could cause a great economic loss. Therefore, the tunnel structure shall be the one which can be repaired as soon as possible, and the fire protection methods need to be selected among those which enable the service to start as early as possible. The necessity of the fire protection works is evaluated for the tunnel structure with the consideration of the expensive tunnel construction cost and the economic effects of the tunnel service. Naturally, the fire protection works, which can protect the tunnel linings from the tunnel fire with small repairs, are inevitable. Design engineers of the fire protection works estimate the scale of fire from the degree of damages on the linings and its repair cost, the effect of fire extinguishers placed inside of the tunnel, the secondary disasters in accordance with the tunnel lining damages if any, and the ratio of fire protection cost calculated from tunnel operation cost. Based on this information, the engineers design the fire protection works according to the permissible limits Among the design cases of the tunnel fire protection in Japan, as shown in Table 1, there is no cases that used the fire temperature-time curve to design the fire protection works for large fire caused by vehicles catching fire. However, the most of cases used 30-60 minutes for fire duration based on the entry prohibition of dangerous goods carrying vehicles or the effect of early fire fighting. This paper will study the variation between different methods used for fire protection in road tunnel in Japan to evaluate them and try to found some recommendations. Especial l care will be attention to Polypropylenes (PP) which is starting to be applied lately."

Jan 1, 2016

By J. Morris

Petro-diesel is a common collector for fine coal froth flotation but partitioning of diesel range organics (DROs) in process streams has not been widely studied. Preliminary research suggested that under normal dosing schemes total residual DRO in process waters should be limited to the sub-ppm water-soluble fraction (WSF). Further, polycyclic aromatic hydrocarbons (PAHs) should partition proportionately with DRO. The purpose of this study was to confirm these findings in laboratory flotation tests. Total DRO and specific PAHs were measured in tailings and concentrate streams, and coal recovery and ash rejection were tracked. Results show that concentrate waters consistently had higher DRO than tailing waters, and DRO in both streams generally increased with increasing diesel dosage. DRO again appeared to be limited to the WSF and PAHs tended to partition proportionately with DRO. Results indicate optimal flotation performance should generally coincide with minimal DRO partitioning to process waters. Under typical operating conditions residual DRO should not present an environmental concern; however, conditions should be avoided that allow significant overdosing of diesel.

Feb 23, 2014

By R. V. Ramani, S. Shankar

The phenomenon of re-entrainment is seen in environments such as sand dune formation, soil erosion, fugitive dust emission and the spread of radionuclides from accidents involving nuclear weapons. A thorough review of existing literature reveals that work on re-entrainment of dust in mine atmospheres is scant. The present study was undertaken as a part of ongoing research at the Generic Mineral Technology Center on Respirable Dust at the Pennsylvania State University on the development of methods to predict ambient dust concentrations in mine atmospheres (Ramani, 1983). The contribution of re-entrainment to the spatial and temporal concentration of dust in mine airways is being studied. The research has included wind tunnel and in-mine studies. A set of seven experiments was performed under controlled conditions in the US Bureau of Mines' Lake Lynn Laboratory mine. Two types of source coal dust, anthracite and bituminous, were subjected to various airflow rates and were subjected to walking by two different individuals. Six sets of instruments were used along the test section for sampling airborne particles. The average air velocity just above the coal dust bed varied between 2.1 to 3.2 m/sec. Due to re-entrainment as a result of the airflow conditions, the average respirable dust concentration in the center of the mine airway increased to 0.09 mg/m3 (standard deviation = 0.03 mg/m3) from an initial value of 0.02 mg/m3. The concentration of all (total) airborne dust increased to 0.17 mg/m3 (standard deviation = 0. 10 mg/M3) from an initial value of 0. 02 mg/m3. The action of people walking, however, caused higher amounts of re-entrainment. The average concentration of respirable and total dust at the center of the mine airway increased to values of 0. 28 mg/m3 (standard deviation of 0.12 mg/m3) and 1.53 mg/m3 (standard deviation of 1.0 mg/m3), from initial values of 0.03 and 0.05 mg/m3, respectively. It was observed that the dust concentrations were much higher near the floor, immediately at the end of the coal-dust bed. Depending on the level of activity and the amount of dust deposited in the mine airways, re-entrainment may become an important source of airborne dust in areas away from the point of actual mining.

Jan 1, 1996

By Aaron Archer, James Parkes

This paper presents design considerations for the major underground elements of the pending BCRUA Phase 2 Raw Water Delivery System Project. These elements include two Lake Taps; an 8,800 LF, minimum 10-ft OD intake tunnel; a suction chamber with 6 Pump Shafts; a 30-ft diameter, 300-ft deep Main Shaft; a 2,600 LF Transmission Tunnel with 78-inch steel liner; and a 130-ft deep shaft on the Transmission Tunnel. The tunnels and shafts will be excavated through the Glen Rose limestone. The design development included consideration for technical requirements, easements, third party commitments, previous local project experience, and constructability based on contractor outreach.

Jun 13, 2021

By Zoë Dugdale, Gerald Poplin, Tim Bauerle

"Fatigue presents several challenges for the mining industry. Depending on the specific occupation, daily work or operational setup on any given mine site, mining jobs can have a fair amount of labor-intensive tasks mixed with monotonous and repetitive duties. Combined with the long working hours and shift-work schedules of mining work, the prevalence of fatigue in mine workers may seem rather unsurprising.Mining is certainly not alone in facing the challenge of addressing worker fatigue. Indeed, many of the characteristics above mirror the similarities of fatigue in other industries, such as health care, aviation and security. To the extent that fatigue in mining acts like fatigue in any other industry, then any fatigue management applications, trainings, or interventions in existence can be borrowed from other industries and applied to mining in a cookie-cutter approach. However, some have argued that mining in particular is especially susceptible to increases in the prevalence of fatigue beyond the characteristics listed above due to the multifaceted combination of factors in mining environments associated with fatigue: dim lighting; limited visual acuity; hot temperatures; loud noise; highly repetitive, sustained, and monotonous tasks; shiftwork; long work hours; long commute times due to mine site remoteness; early morning awakenings; and generally poor sleep habits (Canadian Centre for Occupational Health and Safety, 2012; Legault, 2011). Legault (2011) in particular argues that it is the combination of these factors simultaneously that can make mineworkers particularly susceptible to sleep deprivation and fatigue in comparison to other industries where these factors are often not present all together. If fatigue looks and acts different in mining, as others have argued, more research is needed to determine if, how, and why worker fatigue might need to be managed differently in mining.While the burden of fatigue on the mining population has not yet been evaluated thoroughly, methods and measures of fatigue management remain a popular point of discussion. Many commercial suppliers and consultancy groups have begun to develop technologically based fatigue monitoring systems (McMillian, 2013). Some technologies can monitor vehicle operators for indicators of wakefulness, such as percent eyelid"

Jan 3, 2018

By A. Arik

Reliable ore reserve estimates for deposits with highly skewed grade disributions are difficult tasks to perform. Although some recent geostatistical techniques are available to handle problems with these estimations, ordinary kriging or conventional interpolation methods are still widely used to estimate the ore reserves for such deposits. The estimation results can be very sensitive to the search parameters used during the interpolation of grades with these methods. This paper compares the ore reserve estimates from ordinary kriging using several cases in which certain search parameters are varied. The comparisons are extended to different mineralizations to show the changing effects of these parameters.

Jan 1, 1990

By J. A. Restrepo, K. D. Luxbacher

"The U.S. underground coal mining industry has recently seen the occurrences of several multifatality events that have interrupted an otherwise steadily improving safety record. These events transpired even with an unprecedented level of government regulations and safety technologies. These events may indicate that current safety practices have reached a level of diminishing returns. Risk management, a safety approach that has been successfully applied in numerous industries including mining, may provide a means to overcome this plateau. Riskgate is an Australian mining risk management program that may be successfully applied in the United States. However, fundamental differences between the Australian and U.S. coal mining industries prevent direct implementation. This paper discusses aspects of the Riskgate body of knowledge that require adaptation for its application in the United States. IntroductionThe underground coal mining industry in the United States has recently seen the occurrences of several high profile, multifatality events. These events transpired in the midst of an unprecedented level of government regulations and modern safety technologies. The recent increase in fatal events in conjunction with minimal declines in fatal and nonfatal injuries over the past decade may signify that current safety practices have reached a level of diminishing returns. In order to surpass this plateau, a modification to the manner in which the mining industry approaches worker safety may be warranted.The implementation of a risk-management- based approach may potentially provide a means for not only surmounting the current safety stagnation but also for achieving the long-desired objective of zero harm.Riskgate is an Australian risk-management- based body of knowledge that shows great potential for application in the United States. This paper discusses aspects of the Riskgate body of knowledge that require adaptation for the U.S. mining industry. The proposed adaptations are based on differences in operating practices and government regulations. This discussion will focus on the three major U.S. risk areas of explosion prevention, ground control and moving equipment."

Jan 1, 2015

By Subhas G. Malghan

Feldspathic deposits occur widely throughout the United States, but North Carolina, California, Connecticut and South Carolina accounted for over 80% of the total domestic feldspar output for the year 1973.1 Pegmatites and granites constitute the major feldspar reserves of the United States,2 and in addition, feldspar is produced as a by-product by firms whose major products are spodumene and mica.3 Feldspar is concentrated by hand-cobbing and flotation; the latter forms the major method of separating and concentrating feldspar. Feldspar flotation is practiced in the United States, Mexico, Finland, Norway, West Germany, Japan and the USSR. According to the U. S. Bureau of Mines estimates, the production of feldspar in the United States and rest of the world were 704,000 tons and 2,514,000 tons respectively. Feldspar is principally used as a flux in making glass, pottery, porcelain, enamel,-tile and other ceramic products. In recent years, the domestic feldspar industry is faced with a number of problems. As a result of increased cost of energy and the introduction in 1972 of new legislative programs relating to air, water, and noise pollution, land-use restrictions, and mined-land rehabilitation, the production costs have increased. Apart from the increased cost of operation, an operational problem exists with the feldspar producers in North Carolina, especially those in the Spruce Pine area. This problem is concerned with the use of hydrofluoric acid in the feldspar flotation. Feldspar producers in Spruce Pine, North Carolina have been discharging process waste water into the North Toe River. The mill waste water contains active fluoride ions. Fluoride in excessive concentrations is undesirable in waters used for drinking. It is stated that water

Jan 1, 1976