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By David D. Eyer

Since the decade of the 1990s is nearly upon us, I have focused on what I see are the likely trends featured in new large underground coal mines 10 years from now. I do this from the vantage point of having been involved in the installation of large mines for more than twenty years. Little of the equipment resources we have available today was unknown when I entered the coal business in 1960. There were continuous miners, longwalls and diesel-powered equipment in Europe, monitoring systems, computers, heavy media separation systems, froth flotation and conveyors then as there are now. A substantial evolutionary process has occurred with these and other mining machines and processes. Some evolved only to die out, such as boring-type continuous miners; others, such as longwall systems, flourished. My intuition tells me that since there have been largely evolutionary rather than revolutionary developments in the near past, the same is true of the future, at least for the next 10 years. In other words, the elements of what are in the future are with US now. Some, such as computer-based applications, may evolve beyond our wildest dreams -but I doubt it.

Jan 1, 1988

By P. D. Chamberlain, R. M. Nadkarni, D. J. Kinneberg

Introduction The relationship between precious metal miners and gold refiners has been uneasy over the years. Reasons for this uneasiness and lack of trust include technical factors, economics of scale, and cultural differences. Technical factors take two forms. First, concentrates, precipitates, and sponge produced at the mine site are notoriously difficult to sample. A nonrepresentative sample can be the cause of misunderstanding and distrust. Dote, however, is relatively homogeneous and can be correctly sampled and analyzed with greater reliability. Second, the technology and chemistry of fine gold and silver production is complex and quite different from dote production. Most mining companies are content not to be involved with additional processing steps. From the standpoint of process economies, it is easy to see why miners and refiners are separate groups. Mine location is dictated by the natural occurrence of ore bodies. Heavy capital investment requirements for infrastructure in remote locations usually limits companies to produce the first marketable product from a mine. Beyond that point, the economies of scale and large capital investments for refineries generally dictate that the outputs of several mines be combined to feed a single refinery. The refin¬ing process is so complex that refineries are generally built in larger cities with a skilled labor pool. Therefore, only the largest mines can afford to refine their own output. Lastly, there are cultural differences between the miner and the refiner. The miner, particularly the small gold miner, is by definition a risk taker in a risky business. Refineries, on the other hand, have historically been operated under legal or implied monopolies approved by the government. The government is interested in owning gold, either for currency reasons or because many national mints are major users of gold coins. It is not surprising, then, to find that miners may regard refiners as part of an unresponsive government bureaucracy or, worse, as "city slickers." It is easy for the two groups to distrust each other with these different backgrounds. The interface between miner and refiner does exist and affects nearly all precious metal mining companies and most refineries. This paper discusses the technical and economic aspects of the interface. It points out how both parties can improve the relationship. Technical interface Precious metals selectively dissolve to produce a pregnant solution. They are then recovered from solution by zinc precipitation (Merrill-Crowe process) or by absorption onto activated carbon. This is followed by stripping and electrowinning. At this point, the mining company must decide whether to ship precipitates (or sponge) to refiners or to produce a dote. Some factors the company must consider are the ability to sample precipitates, concentrates or sponge, security of storage, and production rates. An important factor is the incremental cost (capital and operating) of converting precipitates or sponge into dote at the mine. Generally, mines prefer to melt precipitates or sponge to dote to avoid prob¬lems associated with sampling them. There are three types of fur¬naces used by mining operators to melt precipitates to dote. The first and most widely used is a sil¬icon carbide crucible heated ex¬ternally with a gaseous liquid fuel. The crucible is easy to use and slag can be skimmed before pouring dote. This simple system is capable of handling 1 t/a (32,000 oz per year) gold. It could cost as little as $20,000. More complex systems could cost up to $200,000. The second type of furnace is the gas- or propane-fired rever¬beratory furnace. This is usually used only by large-scale opera¬tors in the silver business. Precip¬itates in reverberatory furnaces come in direct contact with the flame. The large volumes of flue gas can carry significant amounts of dust and fume that must be re¬moved from the gas before dis¬charging it to the atmosphere. In the days when the Rand re¬finery in South Africa used reverberatory furnaces, the silver leaving the furnace in the form of vapor and fume was estimated at 2.2% of the total silver charged to the furnace. The gold in the gases was about 0.03% of the gold charged. Most of this silver and gold was recovered in the exhaust gas scrubber system. These scrub¬ber systems can be more costly than the furnace itself.

Jan 10, 1986

By Andrew N. Peterson

US mine operators frequently fail to investigate more cost effective and productive bulk material handling systems because surface mines seem to lend themselves to truck ore haulage. In this country, as a result, use of conveyors to move heavy loads from mine to process facilities has been minimized, if not actually neglected. In contrast, there are more than 50 conveyorized surface mines in successful operation around the world. These mine operators have learned that properly applied conveyorized systems can offer major savings in capital and operating costs, which contribute to improved profits when combined with other proven mining technologies. Growing acceptance and application of conveyorized bulk material handling in surface mines also points up how unique each mine is and how careful planning contributes to maximum mine effectiveness. Because of these differences, mining executives and technical and operating staffs need to develop an understanding of three factors in applying conveyorized bulk material handling in surface mines: • Why each mine will benefit from the type of automation permitted by conveyorized operation, •What kind of equipment is available, and • What applications most effectively demonstrate the first two factors in action - hauling either ore or waste. The conveyorized systems considered in this presentation have production rates from 0.5-2.7 kt/h (500-3,000 stph). Worldwide, these systems have been operating since the early 1960s. Advantages of Conveyors Why do you want conveyorized bulk material handling? First, it almost always provides lower operating and maintenance costs. Second, it frequently requires lower initial capital costs and almost always requires lower capital costs over the life of the surface mine. Third, it provides comparable operating availability, and finally, it frequently gives comparable operating flexibility - depending on the mine plan. Cost avoidance can be accomplished with modern production methods. These, in turn, permit increased productivity and reduced operating costs such as those for energy, maintenance, and manpower. It has been demonstrated in European surface mines and elsewhere, that conveyor systems frequently require lower initial costs than does truck haulage. Almost always such operations require lower capital costs over the mine life. Those costs include the continual addition of haulage trucks to both accommodate the increasingly difficult haulage routes and fulfill replacement requirements when trucks wear out. Conveyor systems handling ore in numerous large crushing and port facilities, which have operated since the early 1950s, have clearly demonstrated a useful conveyor life of more than 25 years. In contrast, off-highway trucks have life spans of six to eight years. The following examples illustrate comparative capital costs to purchase conveyor systems and comparable truck haulage units. Example 1 The ore haulage route from point A to point B is level and 610m (2,000 ft) long. The material weighs 1.8 t/m3 (110 lbs per cu ft) and must be transported at a rate of 1.8 kt/h (2,000 stph). The installed capital costs to provide a properly designed conveyor that will transport the described material from point A to B is about $450,000. The capital cost to purchase three 77-t (85-st) off-highway trucks and one spare truck - which would provide equivalent capacity - would be about $1.2 million. The truck cost estimate is based on a 6 min. or 771 kt/h (850 stph) truck cycle time. Truck efficiency is estimated at 0.8. Each 77-t (85-st) truck would have an actual haulage rate of 617 kt/h (680 stph). Therefore, three trucks would be necessary to transport the designated tonnage of 1.8 kt/h (2,000 stph). A movable crushing plant would be located at point A for the conveyors and a permanent crushing plant at point B for the truck haulage system. Capital costs for these primary crushing plants were not included in the calculations for either system because the capital costs are frequently comparable. Example 2 The transport route from point A to point B is 610 m (2,000 ft) horizontally and 122 m (400 ft) vertically - on a 20% grade (Fig. 1). The material weighs 1.8 t/m3 (110 lbs per cu ft) and must be moved at a rate of 1.8 kt/h (2,000 stph).

Jan 6, 1983

By M. L. Harris, I. Zlochower, M. J. Sapko, I. E. Perera

Experiments conducted with limestone dusts and dolomitic marble dusts have indicated that when rock dust is wetted and subsequently dried, it becomes a solid, non-dispersible cake. However, in order to be effective, rock dust must be able to disperse as individual particles to inert. To counteract this, rock dust manufacturers created treated rock dusts that will resist caking after moisture exposure. National Institute for Occupational Safety and Health (NIOSH) researchers conducted a series of laboratory-scale experiments on four base rock dusts and their treated counterparts to assess the effectiveness of various anti-caking additives after being exposed to moisture and then dried. The dusts were exposed to moisture using humidity cabinets having a high relative humidity (99% RH) and by also exposing the rock dust bed to water through bottom wicking. The dusts were then evaluated for dispersibility after drying using the NIOSH-designed dust dispersion chamber. The anticaking additives were different concentrations of stearic acid, oleic acid, and xylene-based surfactants. All results were compared to a reference rock dust used to conduct large-scale experiments in the Lake Lynn Laboratory (LLL), Fairchance, PA. When the untreated dusts were dried after exposure to moisture for one day, no dispersion was measured. However, rock dusts treated with anti-caking agents were readily dispersible even after exposure to moisture for six months. This report details the analysis and characterization of anti-caking additives using the NIOSH-designed dispersion chamber and the 20-L explosion test chamber. INTRODUCTION In order for a coal dust explosion to propagate, five elements are required. In addition to the fire triangle in which three elements are necessary to sustain a fire—fuel (coal dust), heat (ignition source), and an oxidizer (oxygen in air)—a combustible dust explosion requires dispersion of a dust cloud (pressure wave) and confinement of a dust cloud (underground mine entry) (1). Coal dust explosions can originate anywhere in a mine. For example, when a small volume of a flammable methane and air mixture is ignited in a closed end, the high-temperature gases rapidly expand to create a pressure wave, sometimes referred to as a “pioneer wave,” that may steepen into a shock wave as it propagates away from the ignition source. The shock wave produces a wind that disperses the dust preferentially from any elevated and exposed surfaces (roof, ribs, belt structure, cribbing, etc.). Factors that are known to affect the intensity of an explosion are the dust particle size, the location of the dust within the entry, the dust dispersibility, and the volatility of the coal dust (1). Particles less than 75 μm (< 200 mesh) in size are most reactive (2). Dusts that are located on the roof, ribs, and elevated surfaces are more readily dispersed than dusts on the floor. Therefore, application of quality rock dust in sufficient quantities is essential to inert coal dust and to prevent continued flame propagation. 30 CFR 75.402 and 75.403 require 80% total incombustible content be maintained within 40 ft of the face, and 30 CFR 75.2 defines rock dust acceptable for use in underground coal mines. It also defined that “when rock dust is wetted and dried, will not form a cake”.

Jan 1, 2019

By R. Wisniewski

Every underground coal mine in the United States must deploy and operate a wireless communication and tracking system. This paper addresses the reliability and availability of an installed tracking system and the communications infrastructure that supports it. A particular interest is the requirements for the systems to operate continuously without failure after a mine disaster for 96 hours, and the requirements in the MINER Act for the tracking systems to be ?calculated to be serviceable? and the communications systems ?redundancy?. These requirements imply a certain reliability and availability. This paper describes a quantitative way to assess these systems requirements, using the tools that are available and commonly used by the Reliability, Maintainability, & Availability community.

Feb 23, 2014

By J. R. Tonry

In the grinding of dry non-metallic materials such as rocks, ores, gypsum, lime, and cement clinker, it is recognized that only a relatively small portion of the energy is utilized for actual size reduction, and the major portion of the energy used is converted into heat. As a result, heat is generated inside grinding mills imparting to the ground product a higher temperature than that of the mill feed. In some cases, as for instance in grinding cement clinker and gypsum into finished cement, it may be desirable to keep this temperature increase within certain limits, to avoid any change in the properties of the product and, because consumers may specify a maximum temperature of the finished product for reasons associated, with the tulimate use of the cement. The actual proportions of heat and useful work are somewhat indefinite. Some tests have indicated that nearly all the energy is converted into heat, and. other investigators have found that they could account for "everything except the noise." Investigations sponsored by the American Institute of Mining and Metallurgical Engineers, and carried out with an adiabatic calorimeter, indicated that a surprisingly high 19 percent of the energy might actually be used for size reduc¬tion. However, for the purpose of the following discussion it will be assumed that: (Fig. 1) 10% is lost in motor and gears 10% is lost by radiation and convection from the mill body 10% is used for size reduction, and. that 70% of the energy input leaves the mill as heat in the ground. product. A typical example (Fig. 2) would be a 7x22-ft tube mill operating in open circuit, driven by a 400 hp motor, charged with 77,000 lb of grinding media and producing 70 bbl or 26,300 lb of cement per hour. Reducing this cement from a clinker size of 96 percent passing a No. 16 mesh sieve to a specific surface of 3,230 sq cm per gm (Blaine) will increase the temperature of the cement approximately 143F above the temperature of the feed, as explained later. If the tempera¬ture of the clinker therefore is 125F, the finished cement will be 268F, which in some cases may be too hot. : When cement temperatures approach a range during grinding where dehydration of the gypsum becomes a problem, a logical consideration would be some means of reducing the temperature before it attains the range conducive to gypsum dehydration. Regardless of the varying degrees of heat generated within the mill or mills during grindingto various finenesses, consideration of the maximum safe limit for any type of cement being ground, which may vary fromplant to plant, govern in refining the mill circuit to obtain a safe temperature range. All plants are not necessarily required to do the same cooling job, and may or may not use cement coolers following the grinding circuit. (Not discussed in this paper). In the past, various means have been employed for controlling this temperature increase, Such means have included water cooling of the outside of the mill shell; equipping the shell with cooling fins; injection of moisture inside the mill; ventilation through the mill; and., in cases of closed-circuit grinding, drawing cooling air through the classifier; the purpose in all such cases being to remove heat from the grinding system.

Jan 1, 1958

By Joseph J. Feiler

Fires in underground coal mines are persistent problems anywhere in the world that coal is mined. Coal fires pose safety and health hazards in the form of mine subsidence, loss of energy reserves, destruction of property and surface improvements, and air pollution. In 1995, the US Bureau of Mines (US-BM), in cooperation with the Colorado Division of Minerals and Geology (CDMG),entered into a contract with Goodson & Associates Inc. (GAI) to design and field test the effectiveness of a new foamed grout technology called ThermoCell. GAI is a Lakewood, CO geotechnical and mining reclamation engineering firm. The company developed ThermoCell to control and extinguish underground coal fires. The viability of the special grout and the technology of application were established during a full-scale field demonstration at the abandoned IHI Coal Mine fire, near Rifle, CO. Following acquisition of additional funding by CDMG in 1999, Goodson returned to the site in April to continue the grouting to fully extinguish the IHI fire.

Jan 1, 2000

Ceremonies for the induction of four mining industry pioneers into the National Mining Hall of Fame will be held Saturday, Sept. 11, 2010 at the Charles F. Barber Pavilion of the Museum Convention Center in Leadville, CO. The 23rd Annual National Mining Hall of Fame and Museum Banquet will begin with an open house and reception at 5:30 p.m., followed by the dinner and program at 7 p.m. The four inductees are: William Wheeler Coleman who served 46 years, from 1911 to 1957, as president and chairman of the company that is now Bucyrus International of South Milwaukee, WI, a world leader in the manufacture of surface and underground mining equipment. Dr. Allen Van Heyl, Jr., an economic geologist who served with the U.S. Geological Survey for nearly 50 years beginning in 1943. He studied more of the nation?s mineral deposits than most could begin to imagine. Arthur Lakes contributed enormously to the geological and mining sciences in the western United States as a geologist, teacher, writer and artist over a period of more than four decades beginning in 1869. The Arthur Lakes Library at the Colorado School of Mines, Golden, CO, is named for him. Samuel Calvin McLanahan, through his inventive genius, changed the direction of his family?s company from that of a foundry to a leading manufacturer of minerals processing equipment to become today?s McLanahan

Jul 1, 2010

By A. L. Mular

Optimization has been defined as the procedure of locating the best of something or the best way of doing something (Mular, 1971). Several texts (Himmelblau, 1972; Ray and Szekeley, 1973; Box and Draper, 1969; and Lee, Adams, and Gaines, 1968) on the subject are available. Such techniques have been placed in two categories, namely, off-line optimization and on-line optimization. For the former, an optimization model is employed; for the latter, a black box approach is involved. The essence of an optimization problem becomes obvious, when a response surface is considered. Suppose that a response (in this case, a criterion of improvement such as profit per day; grade of concentrate per day) denoted by Y, depends only on two variables, X1 and X2, which can be manipulated and controlled. The relationship between Y, X1 and X2 may be represented graphically as shown in Fig. 1. The diagram is called a response surface and its height, Y, is determined by X1 and X2. Points associated with equal responses constitute response contours. The shape is that of a hill, and optimization is the procedure of ascending the hill to reach the top (maximum). In practice, a response surface is subject to disturbances which distort its shape and shift its location from time to time, so that the exact location of a maximum is imprecise. Generally, constraints (restrictions of some sort) on responses and manipulable variables serve to define a region of permissible operation.

Jan 1, 1979

By R. L. Neman

Southern Oklahoma (including the Arbuckle Mountains) has outcrops of rocks representing Precambrian, Paleozoic, and Cretaceous ages. Thus, rocks of every geologic age in the Paleozoic and Mesozoic Eras, except the Jurassic and Triassic Periods, are present in south-central Oklahoma. With rocks of such an enormous age range present in a relatively small geographic area, it is little wonder that a wide variety of economic rock and mineral resources are locally present. This report will describe the occurrence, mining, processing, and end-uses (dictated by chemical and physical properties) of the Precambrian Troy Granite, the Cambrian Royer Dolomite and Fort Sill Limestone, Ordovician silica sands of the Simpson Group, Ordovician limestones of the Viola Springs and Welling Formations, and Ordovician Sylvan Shale. In general, the more the end-use depends upon chemical composition and purity, the greater the price that can be demanded for such-minerals. The not-so-successful attempts to mine zinc, manganese, copper, and iron from the Arbuckle Mountains also will be discussed briefly, and I will provide a sermonette on analytical chemistry and its usefulness to corporate CEOs. I may be one of the few persons at this Forum on the Geology of Industrial Minerals who is not a professional geologist. I am an analytical chemist specializing in geochemistry. In particular, I investigate trace elements in rocks and their consequences in industrial processes. As such, I have consulted to the mining industry (and their clients) for two decades, always with the intent of improving service and product quality.

Jan 1, 1999

By YUSONG MIAO, DI WU, XIANRONG YAN, YIPING ZHANG, JIE LIN, KEBIN LI

Rock fragmentation has been a concern in hard-rock mining for the mining industry. Rock fragmentation distribution is an important index to measure the blasting effect. It not only affects the cost of drilling and blasting, but also affects the efficiency of subsequent operations, such as loading, transportation and secondary crushing.

By A. Bobet

Design of a new underground laboratory is underway through the auspices of the United States National Science Foundation. The Deep Underground Science and Engineering Laboratory (DUSEL) is scoped to provide a diverse group of researchers with a dedicated underground facility capable of supporting a broad spectrum of fundamental and applied research at depth in the Earth?s crust. Key research partners in the endeavor are physicists, biologists, geoscientists and engineers. Engineers are not only designing the underground facilities, but are also actively involved in developing research initiatives. This paper will introduce the DUSEL engineering research program to the mining community, provide an overview of the site, geology, and laboratory facilities, and describe some key program initiatives. The particular technical challenges and opportunities afforded by the construction of DUSEL and the performance of the integrated science-engineering program will be discussed by reference to a subset of research initiatives that are currently under development: Cavern Design, CO2 Sequestration and Transparent Earth. These research initiatives target the development of new techniques that can support improved subsurface investigation, design and construction procedures. An increased use of the subsurface can actively contribute to the development of new, more sustainable solutions for use in mining and civil engineering practice.

Jan 1, 2011

By Allan H. Caverson

Over the past nine years a means for measuring the distance between the mine roof and floor has been developed at the White Pine Mine which yields relevant information utilized in the mining operation. The technique known as "convergence!&apos; is an efficient, low cost way for obtaining large quantities of data for predicting roof falls, caving activity, and overall mine stability. From a limited introduction in 1964 related to monitoring an experimental longwall project, the activity of convergence measurements has been expanded to become a production tool now found in all sections of the mine. Presently, the program involves four main types of activity: 1. Monthly measurements in areas known to be active, and in sample blocks scattered throughout the mine for a long-term stability study. 2. Semi-monthly measurements along vital travel roads, belt drifts and compressor sites. 3. Weekly measurements in areas where men are working. 4. Daily measurements in pillar-recovery and caving operations. Today, one field engineer and six technicians are involved full time in convergence work. Rock Mechanics technicians have installed approximately five thousand stations since the start of the program and of this number, over twenty-five hundred active stations still comprise the mine-wide network spread over the more than five square mile extent of the White Pine Mine workings.

Jan 1, 1973

By D. Hulse

"The science of “optimal economic pit design” has been highly refined in the last decades. Even with the proliferation of optimizing and heuristic algorithms exploiting ever faster computers, the most common input is a single block model and a single set of cost assumptions, each of which is an estimate and prone to errors. An analysis of price assumptions produces a suite of nested economic shells, each with its own quantities of ore, waste, grade, and profit, but due to irregularities in the mineralized body, the growth of these shells can be erratic. To control the impact of the errors of the model and cost assumptions when choosing the pit shell for design, graphs of pit shells characteristics, such as stripping ratio, cost per unit of product and profit/ton, can be analyzed to consider points with higher stability, or robust pits. Selection of robust shells for a pit limit and for push backs can help to understand the impact to profit and risk. The robust shells also guide the preferred solution sets for final pit and cutoff optimization. INTRODUCTION “An open pit mining operation can be viewed as a process by which the open surface of a mine is continuously deformed. The planning of a mining program involves the design of the final shape of this open surface.” Optimum Design of Open-Pit Mines, Lerchs, H. and Grossmann, I. Transactions C.I.M. Volume LXVIII 1965. Traditionally an analysis of economic pit shells and sensitivity was performed by varying the input metal price. This was done with both floating cone algorithms as well as early versions of the Lerchs-Grossmann (L-G) algorithm. This gave an indication of the pit sensitivity to price but since other variables also change, some with metal price (perhaps steel and equipment), and some independently (fuel and tires) the understanding of these different pits was restricted. In addition, a run of the program could take hours, making a detailed analysis of small changes unwieldy. The L-G algorithm was programmed by a variety of people and sold as part of commercial mining packages, however it was first and most successfully commercialized by Jeff Whittle in 1984. When Whittle’s 3-D™ was expanded to 4-D the parameterization of the economic inputs was considered and the ability to run a suite of “pit shells” became automatic. The competing NPV Scheduler™ program sold by DataMine™ offers similar pit shell analysis capabilities."

Jan 1, 2018

By NILAMADHABA SAHU, Gajanan U. Kapure, Pankaj Kumar, Sunil Kumar Tripathy

Chromite ore processing tailings and low-grade manganese ores are typically considered waste due to their limited or negligible utility, leading to environmental and storage concerns. Researchers globally have explored various methods to utilize or upgrade these wastes, particularly because dumping chromite ore has been linked to severe health issues through Cr(VI) leaching. Individually, these ores lack economic value, and there has not been research on simultaneously reducing both low-grade ores. In this study, the focus lies on smelting these ores together, aiming to create a precursor alloy for 200 series stainless steel scrap. Initial research indicates the potential for scrap formation, validated through laboratory experiments with varying coke rate, basicity and holding time. The investigation discovered that smelting this combination could yield a metal product consisting of 59 percent Fe, 24.93 percent Cr, 7.56 percent Mn, 0.62 percent Ni and 0.93 percent Si. The optimum basicity was found to be 0.6 with 80 percent recovery. Notably, this process eliminates intermediate steps in 200 series stainless steel production, potentially reducing overall carbon dioxide emissions. This proposed method represents a cleaner, sustainable approach to repurpose these two waste ores, projecting a net profit of US$330/t.

May 1, 2024

By Allan T. Fisk, Carl R. Peterson, Robert G. Lundquist

A long recognized goal in high speed tunneling and mining has been the development of a continuous drill and blast excavation capability. Both the advance rate and the economy of drill and blast tunneling can be significantly improved if the conventional cyclic process can be carried out continuously. Obviously, any continuous drill and blast tunneling machine must be an "all function" device, performing drilling, explosive loading, initiation, mucking, ventilation, roof support (if necessary), and perhaps other functions, essentially simultaneously, while remaining at the face throughout. Furthermore, such a machine must do all these things under remote control. THE SPIRAL BLAST PATTERN Several continuous drill and blast tunneling concepts have been proposed. Of these the Rapidex spiral blast pattern, taking advantage of a partially self-shielding geometry, seems to require the least shielding and hence offers the maximum access for mucking, although from the outset it was clear that remote mucking would present a major design challenge. The Rapidex continuous spiral blast concept uses an unusual blasting pattern that, under the geological conditions tested, has proven to be an effective and efficient means of fragmentation. The concept has a self-shielding characteristic which permits a lightly shielded machine to remain at the face during blasting. The pattern produces a spirally proceeding tunnel face, much like one turn of an auger. The leading portion of the spiral surface is connected to the trailing portion by an axially extending plane surface or bench. The ideal geometry is illustrated in Figure 1 for a horseshoe tunnel section.

Jan 1, 1979

By Nick Karl, David Wilburn

"The mission of the U.S. Geological Survey (USGS) National Minerals Information Center (NMIC) is to collect, analyze and disseminate information on the domestic and international supply of and demand for minerals and mineral materials essential to the U.S. economy and national security. Understanding mineral exploration activities and trends assists government policy makers, minerals industry decision makers and research entities in identifying where future sources of mineral supply are likely to be discovered, the amount and type of these resources and factors that may affect exploration and development.This review summarizes significant exploration trends related to active sites and budgets, mineral commodities and regional factors for the years 2001-2015. Data were compiled by specialists in the USGS-NMIC, and reported annually in the USGS-NMIC Minerals Yearbook series and in the May issue of Mining Engineering magazine. External data for these analyses were derived from industry sources, published literature, and SNL Metals & Mining, an offering of S&P Global Market Intelligence (New York, NY).The USGS-NMIC compiled exploration site data for more than 80 mineral commodities, focusing on base metals, diamond and precious metals. More than $138 billion constant U.S. dollars were budgeted by the minerals industry from 2001 through 2015 to explore more than 16,000 mineral deposits globally (SNL Metals & Mining, 2016a). Annual analyses identified where mineral exploration took place by principal commodity target, ranked the magnitude of activity in each region, identified the factors that most affected changes in exploration activity and highlighted developments that led to changes in global supply or increased diversity of supply to the United States. Geographic classifications noted in this report were Africa, Australia, Canada, China, Latin America, Pacific, Russia, United States and Rest of the World."

Apr 1, 2017

What is your assessment of the status of the mining industry as we see some evidence of an economic recovery? I am optimistic about the short and midterm prospects for the industry and, hence, for the professionals in the industry that constitute the majority of the SME membership. All who will read this interview recognize that the quality of life we enjoy today is largely a result of our achievements in the mining and minerals processing sectors. I believe that the sustainability of that quality of life and the aspirations of other sectors of the global community to attain that same lifestyle will significantly depend on the continued successes of these industries. Looking at some of the traditional economic indicators, we see predictions of continued increases in gold prices during the next 12 months as a new round of quantitative easing keeps real interest rates low and drives excess capital flows from countries with trade surpluses - who have traditionally parked their money in U.S. government bonds - into other investable assets, such as gold. On the fuel side of the industry, we have during the last decade seen a steady rise in the cost of coal, and some of the recent spot prices have seen dramatic increases. Some suggest that coal prices may rise sooner than anyone expects, as global reserves are revised downward. This is based on the hypothesis that some of the main coal-producing countries are overestimating supplies and that coal prices could start rising far sooner than anyone thinks - with obvious serious implications for energy policy. Those forecasters note that, for the past couple of decades, global supply has been dropping at a faster rate than consumption.

Jan 1, 2011

By W. M. Kidd, P. J. Duport

INTRODUCTION The enquiry of the Royal Commission on Health and Safety of Workers in Mines of 1976, known as the Ham Commission after its chairman, Dr. J. Ham , now president of the University of Toronto, was one of the activities surrounding the upturn in the fortunes of the Canadian uranium industry and its markets in the mid-seventies. Although the regulation and licensing of Canada&apos;s ten major mine/mill facilities employing six thousand or more uranium mines is a federal concern under the Atomic Energy Control Act, this Commission, which paid particular attention to health and safety in uranium mines, was appointed by the Province of Ontario. Further provincial enquiries in British Columbia, Saskatchewan and Newfoundland have been aimed at quantifying, reducing or eliminating the environmental and health impact of uranium production. This work has created a mosaic of provincial regulation in what is essentially a field of federal jurisdiction. Various organizations of the federal government related to its regulatory function in the uranium industry are outlined in Figure 1 showing the matrices of regulatory, advisory and research activities associated with the exploitation of Canadian uranium resources. A more detailed examination [ ] of the governmental (federal and provincial) activities, commissions, etc., in the Canadian uranium industry indicates a definite parallelism of effort, if not of scale between the two levels of government in the execution of their roles in occupational and environmental health and safety and is presented here to explain the complex stage onto which the Canadian Institute for Radiation Safety has just entered. The development of the Institute and its precursors together with current and planned research activities are described. BACKGROUND Traditionally and constitutionally, natural resource exploitation and its regulation is under provincial jurisdiction; however, the uranium industry has been under federal control since the Second World War when security measures necessitated the creation of the Atomic Energy Control Board (AECB). Health and safety aspects, in terms of inspection, compliance and environmental monitoring are performed on behalf of the AECB by provincial labour inspectors (Saskatchewan and Ontario) and Ministries of Environment. Non-radiation health and safety matters are also enforced under the federal Canada Labour Code by provincial inspectors. In support of licensing and standard-setting functions, major research programs have been initiated and expanded at both the AECB and the Canada Centre for Mineral and Energy Technology (CANMET), formerly the Mines Branch of the Federal Department of Energy, Mines and Resources). CANMET established a Mining Research Laboratory at Elliot Lake, Ontario in 1965 to conduct research and development aimed at improving production capability, providing information on the security of uranium supply and investigating the hazards of mining and their implications for the health and safety of the miners. The provincial route in assessing the costs and benefits of uranium production has attempted to be far more conclusive in nature. While some on-going studies are funded, periodic inquiries by Royal Commission have become the accepted practice. Six such inquiries have been conducted in four provinces and widely differing policies have resulted from their findings and recommendations. For example, while the government of British Columbia in the Fall of 1980 declared a seven-year moratorium on(2) uranium mining and exploration in the province, the province of Ontario&apos;s crown utility "Ontario Hydro" financed the rehabilitation of a mine/mill complex at Elliot Lake. The latter instance is not surprising considering that the final report of Ontario&apos;s "Royal Commission on Electric Power Planning",(3) concluded that nuclear energy has a continuing role to play in the expansion of Ontario Hydro.

Jan 1, 1981

By Francis G. Stehli

Though sedimentary rocks comprise only about five percent of the volume of the continental crust, they cover about 80% of its surface, serve as important reservoirs for fluids, contain reserves of non-metallic minerals, and have in general been extensively drilled. However, most drilling has been shallow in comparison to the thickness of the crust and such deep drilling as has taken place is very strongly localized in sedimentary basins. This may be seen by reference to Figures 1 and 2 which show the location of wells that drilled deeper than 15,000&apos; [=] 4.6 km. (Figure 1) and those that drilled below 20,000&apos; [=] 6.15 km. (Figure 2). It is apparent that, even in regions of sedimentary cover, direct exploration below six kilometers has been very restricted. In the case of the metamorphic and igneous rocks which make up 95% of the volume of the crust, direct exploration has been much less extensive in terms of both area and depth. The present state of our knowledge of the crust below a&apos; thin surface layer stands in marked contrast to our growing present need for raw materials and the needs of future generations. It also stands in contrast to our need for enhanced, scientific knowledge of the deeper crust, its configuration, its present state, its hydrothermal systems,-its evolution, and its materials. Lessons learned in exploring the third dimension of the sea floor, the vigorous prosecution of seismic profiling, the development of testable models for hydrothermal systems and mineral deposits, the need for better understanding of heat flow, state of stress, earthquake mechanisms, and a host of other phenomena all suggest that it is time to launch a national program for scientific exploration of the crust which uses drilling to test important hypotheses developed on the basis of indirect evidence.

Jan 1, 1985