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By Miguel Reyes, Bruce Whisner, Joseph Bickson, Lincan Yan, David Yantek, Justin Srednicki, Nicholas Damiano, Eric Bauer

Built-in-place (BIP) refuge alternatives (RAs) are designed to provide a secure space for miners who cannot escape during a mine emergency. Heat and humidity buildup within RAs may expose miners to physiological hazards such as heat stress. To minimize the risk of heat stress, Title 30 Code of Federal Regulations (CFR), or 30 CFR, mandates a maximum allowable apparent temperature (AT) for an occupied RA of 35 °C (95 °F). The National Institute for Occupational Safety and Health (NIOSH) has conducted extensive research on the thermal environment of occupied RAs intended for use in underground coal mines. NIOSH research has demonstrated that a fully occupied BIP RA can exceed the AT limit by more than 5.6 °C (10 °F) in mines with elevated mine strata and air temperatures. In this circumstance, an RA cooling system could provide a solution. This paper provides an overview of test methodology and findings as well as guidance on improving the performance of a cryogenic air system prototype by optimizing the flow rate, increasing the tank storage capacity, and improving the efficiency of the heat exchanger of the cryogenic system. This may enable BIP RAs to meet the 35 °C (95 °F) AT limit in mines with elevated temperatures. The information in this paper is useful for RA manufacturers and mines that may choose to implement a cryogenic air system as a heat mitigation strategy.

By Trevor R. Ellis

The extractive industries addition to the International Valuation Standards (IVS) is scheduled for publication in the next edition of the IVS book in January 2005. This will provide guidance for valuation of minerals and petroleum industry assets of all types for all appraisal uses. It will provide asset valuation support to the International Financial Reporting Standards for the stock markets of the world, and a global umbrella standard which can be supplemented for local needs by institutes and regulators. This paper discusses implementation of the IVS within the minerals industry and important issues that the industry should confront.

Jan 1, 2005

By T. Grammatikopoulos, C. Gibson, M. Aghamirian

"Lithium is a silver-white alkali metal that has recently become a target commodity for many junior mining companies. Lithium has a wide range of applications including ceramics and glass, lubricating greases, air treatment, continuous cast mold flux powders, polymer production, and primary aluminium production, but the current popularity of lithium can be attributed to an anticipated increase in demand for lithium ion batteries. The most common lithium-bearing minerals occur globally in pegmatites and granites. Spodumene [LiAl(Si2O6)] is the most desirable economic lithium-bearing mineral due to its high lithium content (theoretical Li2O content of about 8 wt%). However, lithium can also be hosted in petalite, micas, tourmaline, and phosphate minerals. In Canada there are a number of spodumene deposits in Ontario and Quebec at development stage that have the potential to help narrow the forecast lithium supply gap stemming from the widespread acceptance and use of electric vehicles. This paper discusses the beneficiation of hard rock lithium deposits, including an in depth review of the use of flotation to upgrade spodumene. A review of the use of dense media separation (DMS), magnetic separation, and roasting as means to process spodumene bearing ores is also discussed. INTRODUCTION Lithium is a soft, silver-white alkali metal with atomic number 3. As of 2015, the end use of lithium was estimated to be as follows: lithium-ion batteries (35%), ceramics and glass (32%), lubricating greases (9%), air treatment (5%), continuous casting mould flux powders (5%), polymer production (4%), primary aluminium production (1%) and other uses (9%) (Jaskula, 2014). Lithium is found in brine lake deposits containing lithium chloride and in hard rock pegmatite deposits. It can be sold in a range of product types; as mineral concentrate, brine, compound (lithium carbonate or lithium hydroxide) and metal depending on its intended end use (Goonan, 2012; Jaskula 2014). In the 1990s the United States and Chile were the largest producers of lithium globally, primarily from brine operations (Ober, 1994). Most of the lithium compounds produced over this period were consumed in the glass, ceramics and aluminium industries. In the 1980s and 1990s there were two major lithium operations in the United States: brine operations at Silver Peak, Nevada, and a spodumene mine and lithium carbonate/lithium hydroxide plant in Kings Mountain, North Carolina. The Kings Mountain operations ceased production in 1991 and were eventually dismantled in 1994. Brine operations were also active in Argentina and Chile, while the largest lithium ore deposit in the world was operated at Greenbushes, Western Australia. During this period it was predicted that major shifts in demand for lithium would come from the success and widespread use of electric vehicles (Ober, 1994)."

Jan 1, 2017

By Thomas E. Shufflebarger

Definition of glass sand prospects may be modified by constraints which range from demography to critically important product-control. Characteristics of usable raw materials, physical and chemical, are discussed; an ideal raw material is defined. Following field investigations and preliminary sampling, evaluation of selected prospects includes use of modern drilling techniques, viz.: core, percussion (air-hammer), auger, jet, rotary jet, split-spoon and other. Nearly complete core (sample) return is mandatory. Land-use regulations, availability of water and transportation continue to direct exploration in a major sense. But fitting a prospect to burdensome politics nay be considered a decidedly negative factor.

Jan 1, 1983

By C. Waddell

PDMI mines five different grades of ore. Shovel operators were experiencing problems differentiating one material type from another. In 1997 PDMI decided to try GPS ore control to aid operators in identifying material boundaries. Computer generated ore control maps and GPS data defining the shovels' position is fed to a computer on board the shovel. A monitor, located near the shovel operator, displays material types, their boundaries, and the shovels' position and movement in relation to the mining face. This information has reduced errors in material identification by 50%.

Jan 1, 1998

By Bahram Sameit

Blast engineers have been taking advantage of image-based rock fragmentation analysis methods for the past three decades to estimate rock size distributions. These methods utilize a range of image segmentation techniques, from manual to fully-automated, to delineate the edges of rocks in images. Rock delineation results are then converted to physical rock sizes (and percentage passing curves) by scaling the image pixels to correspond to physical measurements. The size scaling process is critical for acquiring physical measurements, but specifc to the limitations of different applications. This article starts by presenting a shovel bucket-based fragmentation analysis system, where scaling is done using the known width of the shovel bucket within the image. It will then describe methods that use pictures captured by digital cameras with scaling reference objects in the view. Finally, the article presents a method that uses three-dimensional imaging to capture images without the need for scaling reference objects.

By Charles B. Manula

This paper describes the development of a mathematical model for simulating the behavior of a longwall coal production system. The longwall simulator is a design simulator incorporating both deterministic and stochastic methods to calculate: (a) the size and density of support; (b) the cutting force, power requirements and haulage speed for the loader-shearer; (c) the conveyor size, speed and power requirements; and (d) delay generation at head and tail-gates and the longwall face.

Jan 1, 1978

By Duluth Engineers' Club, Engineers' Club of Northern Minnesota

"Prospecting and Exploration. Since the Lake Superior ores occur in pockets or distinct bodies and vary much as to character and location, the actual mining of the ores is preceded by much work of an exploratory character. This work includes prospecting and exploration.Prospecting is the term generally applied to the quest for surface indications of ore, or the conditions which would warrant the expectation of finding ore in the vicinity. It includes such 'operations as geological examination, dip needle work, shallow test-pitting, and trenching. The ore bodies of the Mesabi Range are non-magnetic, and dip needle prospecting is therefore valueless. On the Cuyuna range, however, magnetic attraction as evidenced by the dip needle has been extensively employed as a guide to the location of ore deposits; in other localities it has found limited application.Drill Exploration. After the presence of an ore deposit is known or suspected, resort is generally had to exploration by means of diamond or churn drills. On the old ranges geological conditions generally make this manner of ascertaining the exact limits of an ore deposit impracticable; so, if two or three adjacent drill holes develop considerable depths of ore, the sinking of a shaft for underground exploration, development and mining is generally considered warranted. On the Mesabi Range, however, the flat-lying and comparatively shallow characteristics of the ore formation warrant much more extensive drill explorations. On this range, then, an ore body 'is almost invariably followed· out with the drills, and its limits are determined to the point where the complete plan of development can be worked out in advance of actual mining operations"

Jan 1, 1920

By G. E. Viens

The electric arc furnace has characteristics which make it attractive for a number of metallurgical applications. Some of these characteristics are: high thermal efficiency, the possibility of attaining very high temperatures, low off-gas volume compared to fuel-fired furnaces, no impurities are introduced by the heat source, and impurities in only minor amounts are introduced by the electrodes. It also has disadvantages, the chief ones being the relatively high cost of electrical energy compared to fossil-fuel energy and the fact that, when oxide ores are smelted using carbon as reductant, the off-gases emitted are rich in carbon monoxide. As in many other pyrometallurgical processes, fumes and dust are emitted from melting or smelting operations. In many installations, some or all of the off-gases are flared, thereby wasting their energy and contributing to atmospheric pollution. During the last eight years, a shaft-electric furnace has been under development at the Mines Branch, Department of Energy, Mines and Resources, Ottawa, Canada. This project was initiated to try to overcome, or at least minimize, the disadvantages of the electric furnace. Experience on other projects, prior to the beginning of this program, had indicated that preparation of the charge materials, for example by sizing raw ore, sintering concentrates and crushing and sizing the sinter, or agglomerating concentrates into uniform-sized pellets, could make a substantial contribution towards achieving success in arc-furnace smelting projects; This entire

Jan 1, 1971

By Walter E. Dean

Deep-sea manganese nodules are considered to be potential ores of manganese, nickel, cobalt, and copper. Considerable time, effort, and funds have been applied to the study of Se distribution of nodules on the sea floor and the location of economically important areas, but little effort has been spent in understanding the origin of nodules. Most theories that have been proposed to explain the origin of manganese nodules have been based on inorganic physicochemical processes. It is not by coincidence, however, that the area considered to be most economically feasible is in the zone of high biological productivity in the eastern equatorial Pacific Ocean and underlain by siliceous biogenic sediment. The genesis of manganese nodules and the concentration of many trace elements are intimately associated with biological processes.

Jan 1, 1982

By David B. Brooks

I gratefully acknowledge the help of a number of American and Canadian geologists, in both federal surveys and in private firms, who took the time to discuss this problem with me. Hans Landsberg and Bruce Netschert also followed the study with interest and encouragement. In their 1961 monograph, THE FUTURE SUPPLY OF THE MAJOR METALS, Bruce Netschert and Hans Landsberg noted that identified potential resources (that is, known but submarginal resources) of lead and zinc were much lower relative to reserves (that is, known and supermarginal resources) than was the same ratio for other metals.1/ Put another way, it seemed that for such metals as iron, manganese, copper, and aluminum, slightly more favorable economic conditions or modest advances in technology would greatly increase reserves by permitting the exploitation of vest quantities of leaner or deeper or otherwise less valuable mineral deposits. But for lead and zinc, Netschert and Landsberg concluded that either: "(1) there is relatively little material below present cutoff grades; [or] (2) such material exists, but for some reason there are no data.? 2/ This situation, which they called "the lead-zinc anomaly" has been subsequently discussed by other authors. The purpose of this paper is to carry the discussion further by examining the evidence in favor of (1) and (2) and by advancing a third alternative.

Jan 1, 1967

By Andrew B. Pervis

With the ever increasing demand for Finer powders by industry there has been a continuing effort by air classifier manufacturers to improve and offer machinery capable of producing these fine powders. Common to these classifiers is the use of a multivaned rotor through which passes all of the air used to transport the particles to be classified. Rotor revolutions per minute and the amount of air passing through the rotor are the main variables in determining the particle sizes which will be able to pass through the spinning rotor. A simplified equation derived by setting the air drag force carrying a particle through the rotor equal to the centrifugal force due to the spinning rotor's action on the entering air and particle is: Diameter of Particle = [ ] Where K is a function of air viscosity, particle configuration, rotor and blade configuration; RPM is rotor revolutions per minute; M3/sec. is air quantity passing through the openings between the rotor blades.

Jan 1, 1983

By B. J. Arnold

Prior laboratory work has demonstrated -that much of the fine ash-forming minerals entering a flotation froth are there as a result of water carry-over from the bulk contents of the flotation cell (Arnold and Aplan, 1986a). Using a bank of four 300 cu ft WEMCO flotation cells cleaning a well-liberated Lower Kittanning seam coal, test results show that the sulfur and ash content of the froth is directly related to the water content of the froth (or inversely related to the percent of solids in the froth). Reagent changes which result in a watery froth produce a higher ash content in the froth. A direct comparison of laboratory and plant results show that the standard laboratory flotation test produces a product higher in sulfur and ash than that produced in the plant. Caution should be exercised when extrapolating laboratory test results to the plant situation. A method of estimating coal flotation product quality in the plant based on laboratory tests is given.

Jan 1, 1990

By Earl A. Berry

Someone once said, "The safest mine is one in which no one goes into." We all recognize this as being perhaps wishful thinking. We also recognize in it a certain amount of truth and an ultimate goal if we are optimistic. All of us are aware of the many things that have been done, are being done and will be done to reduce manpower in mining. For those of us; who are optimistic about this ultimate goal it would appear from the records-we are more than well on our way to the so called safest mine. Let us see what has been done in the past 20 years. T e period from 1935 to 1956. For example in the coal mining industry: In 1935 there were employed 462,903 men who produced an average of 805 tons per man per year or 4.50 tons per man per day. In 1955 there were employed 225,093 men who produced an average of 2,064 tons per man per year or 9.84 tons per man per day. There are no comparable figures compiled for the metal mining industry as a whole that can be broken down in this manner. However, from examination of figures available for different groups in metal mining there is a trend similar to that in coal mining. No-dbout the above figures reflect the intense development and perfection of machines and mining systems to tear out, transport and process our mineral wealth. The figures also show the mining industry has been able to double its production and at the same time reduce its manpower by half. When you compare the number of men employed today with the number which would have been employed 20 years ago to gain todays production at that time it become apparent that greater safety has been accomplished. For example the years 1935 to 1956 for all mining show. In 1935 there were approximately 649,226 men employed in mining and reports show 1,399 fatalities and 74,913 non-fatal injuries. In 1955 when there were 313,883 men employed in mining 496 fatalities and 25,365 non-fatal injuries were reported. To have produced the same tonnage of material in 1935 that was produced in 1955 it would have required the employment of approximately 1,298,452 men. 2,798 could have been fatalities and 149,826 could have had non-fatal injuries. You can now measure the full impact of what has been accomplished in the past 2o years by the aggressiveness of mine management, the wizardry of our engineering personnel and the thoughtfulness and devotion of our safety people and their programs. Therefore, there is a trend towards the goal of our opening statement. We whoare toptimistic believe this trend will accelerate at a-faster pace. Why? Because anyone engaged in the mining industry today can well afford to invest a minimum of $30,000.00 in capital equipment todisplace the labor of one man. This fact alone is a terrific incentive for mine management to apply and manufacturers to develop equipment of a type to get the men out of the mine. Now you can determine this problem not only becomes one of safety but also one of economics, When productivity is stepped up and manpower reduced management is learning the hard way what it means to them; in the profit and los s column when a few minutes of delay or downtime of costly machines and processes occur. They have learned that fast and efficient communication systems are the best means of combating breakdown, delays, bottlenecks, supply problems, the saving of lives and property and increasing production. One large western metal mine was able to increase Its tonnage by 4000 tons a day by using modernup to date electronic type communication system. The National Coal Board of Great Britain recently allocated 45,000,000.00 to study and develop faster and more efficient communications when a survey indicated what a serious bottleneck poor communication in their present systems of mining turned' out Lobe.

Jan 1, 1958

By T. J. Fronapfel

Impacts to ground water from mining are being comprehensively regulated in Nevada through specific requirements for design, construction, operation, permitting and closure. This program is the nation's most comprehensive for control of activities at mining operations which have the potential to cause groundwater degradation. It encompasses virtually all types of facilities, including placer, physical separation, flotation, testing, leaching and milling. Minimum design requirements are established by regulation, and must be met by each facility. Site-specific monitoring requirements are established for each facility, and are heavily emphasized. Regulatory and technical requirements and relevant permit conditions are presented and discussed.

Jan 1, 1992

By David M. Lapham

In Pennsylvania, 310 sampled sites of clay and shale have been evaluated for: potential use, chiefly as structural clay products, refractories, and lightweight aggregate; lithology; physical properties tests; fired tests, both quick-fire and rotary kiln; major-element chemical analyses, and quantitative five-component X-ray mineralogy for quartz, mica, feldspar, kaolinite, and chlorite-vermiculite-montmoril-lonite. Approximately 80 percent of the samples are of some potential use. Of 220 shale samples, 84 were potential lightweight aggregate sources and 83 potential brick sources. Binary correlations of test data versus potential use indicate that certain empirically determined parameters may be critical. These are: lithology, particularly for medium to super-duty refractories and lightweight aggregate; kaol-finite content for refractories versus low-temperature fired product sources; quartz content illustrating that there is an apparently necessary minimum quantity for brick; quartz content, which is low in high grades of lightweight aggregate; mica content, which is low for refractories and possibly high for lightweight aggregate; total iron, which is low for refractories and shows a 40 percent minimum for lightweight aggregate; carbon dioxide, which is low for refractorfes, beneficial in lightweight aggregate, and probably restrictive for some tiles choroite yermicalite, which is low for refractoies and possibly beneficial in lightweight aggregate. In Pennsylvania, clay and shale materials constitute one of the state's major economic mineral resources. To date, the testing program indicates considerable development potential in brick, tile, and lightweight aggregate industries, and perhaps a future potential for aluminum from shales that exceed 20 percent A12Q3.

Jan 1, 1971

By J. P. Rider, T. W. Beck, J. A. Organiscak

"The National Institute for Occupational Safety and Health (NIOSH), Pittsburgh Mining Research Division (PMRD) has recently developed a series of models utilizing computational fluid dynamics (CFD) to study gas distribution around a continuous mining machine (CM) with various fan-powered flooded bed scrubber discharge configurations in an exhaust curtain working face. CFD models utilizing species transport model without reactions in FLUENT were constructed to evaluate the redirection of scrubber discharge toward the mining face rather than behind the return curtain. The study illustrates the gas distribution in the slab (second) cut. The following scenarios are considered in this study: 100% of the discharge redirected back towards the face on the off-curtain side of the continuous miner; 100% of the discharge redirected back towards the face, but divided equally to both sides of the machine; and 15% of the discharge redirected toward the face on the off-curtain side of the machine, with 85% directed into the return. These models were compared to a model with a conventional scrubber discharge where air is directed away from the face into the return. The models were validated based on experimental data and accurately predicted sulfur hexafluoride (SF6) gas levels at four gas monitoring locations. One additional prediction model was simulated to consider a different scrubber discharge angle for the 100% redirected, equally divided case. This paper describes the validation of the models based on experimental data and the gas distribution results of the CFD models. INTRODUCTION To control methane gas and dust concentrations on continuous mining operations, it is important to provide sufficient quantity of fresh air from the end of tubing or curtain to the active face. In this region, operating machine-mounted water sprays and fan-powered, flooded bed scrubbers can significantly increase the amount of airflow reaching the face [1-3]. However, when an entry is large, especially in higher coal seams, the water spray configuration and the scrubber capacity may not be adequate to maintain sufficient forward airflow to confine the dust cloud to the face. Dust can roll back toward the machine operator as a result [4]. Currently, several coal mines having negligible gas emissions in higher coal seams (2.4 to 3.0 m [8 to 10ft.] thick) with exhaust tubing systems redirect the scrubber discharge back towards the face in an effort to improve dust collection. NIOSH studied the redirected scrubber exhaust techniques for dust and gas control in a full scale CM gallery to assess its potential for industry-wide application [5]. For a CM face, previous studies have concluded that the behavior of gas and respirable dust is a complex process. The distribution/dispersion and transport of gas and respirable dust after they are liberated at the face are governed mainly by their mass properties, the movement pattern of the ventilation air, and interactions with the mining machine and water droplets created by the external water spray systems used for dust control [6-10]. To understand these behaviors in a complex CM environment and to evaluate the effectiveness of various control techniques, numerical modeling has become a necessary supplement to laboratory experiments and field studies."

Jan 1, 2017

By Elgin D. Bell

Within the next, year or two, Western Canada should overtake Mexico and France. to become the worlds second largest producer of elemental sulphur, surpassed only by the United States, By 1965, it should produce about 25% of the world's total elemental production and, about 10% of sulphur produced in all forms. In 1952 Alberta had but one small sulphur recovery plant. By 1962, it had fifteen plants with a total designed capacity of almost 6,000 long tons of sulphur per day and actual production of almost one million long tons per year. This decade of dynamic growth was the result of Alberta's rapidly developing natural gas industry. More particularly it was the result of approval in 1960 to export natural gas in large volumes into the United States. Prior approval to export gas from Alberta to eastern Canada and relatively modest volumes to the U. S. had resulted in the construction of several plants but none were of the scale required to serve the U. S. market.

Jan 1, 1963

By H. Colijn

Belt conveyors have proven themselves for many years as a dependable and low cost method of handling bulk materials at high flow rates. The success of a belt conveyor system greatly depends on the initial loading of the material on the belt. If the material is loaded on the belt at the center, at approximately the same speed and with minimum impact, then most of all belt conveyor problems disappear. Proper belt loading is primarily determined by the engineering and design of the conveyor transfer point. This paper will establish and discuss some general design criteria required for proper loading and transfer of materials from one conveyor to another. Specific attention is given to loading points, chutes, skirt board length and general design of transfer structures.

Jan 1, 1971

By Ning Wang, Tengfei Guo, Wanyan Li, Hanjie Wen, Hannian Gu, Zehai Li

Bauxite residue (red mud) is an alkaline waste derived from the industrial process for extraction of alumina from bauxite ore. Some bauxite residues contain considerable concentrations of critical metals, for example, rare earth elements. Lithium in red mud was also reported as a potential resource. In the current study, a Li-rich red mud was leached using acetic acid to investigate the leaching behavior of lithium followed by neutralizing with hydrochloric or oxalic acid. By neutralizing red mud using diluted hydrochloric acid (0.01 mol/L), 58.04–60.27% of lithium was leached using 25% acetic acid at 95 °C for 60 min. In the meantime, more than 95% of sodium and 85% of calcium were also dissolved in the leachate solution. While oxalic acid (0.5 mol/L) was used to neutralize red mud prior to acetic acid leaching, lithium performed lower leaching efficiencies (42.41–46.88%) in comparison of using of hydrochloric acid–neutralized red mud. Nevertheless, these leaching efficiencies of lithium were close to that of calcium and much higher than those of sodium under the condition. In this study, 25% (v/v) of acetic acid, at 85 °C for 60 min, was demonstrated as optimum conditions for lithium extraction from oxalic acid–neutralized red mud using acetic acid. The results would be useful and of interest for lithium recovery and purification from red mud.