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By M. J. Garcia, Howard Hallman, G. M. T. Marshall, Ken Higby, Louis Cope, Robert S. Hess, John Peters, A. G. Law, William C. Larson

After a good year in 1979-strong mineral demand, adequate prices for most metals, minimal labor problems-1980 was not so good. The US produced $24.8 billion worth of nonfuel minerals last year, up 3.5% from 1979, according to preliminary US Bureau of Mines figures. But the $800 million increase was the smallest annual gain since 1977 and reflected reduced auto and construction industry demand, strikes, and energy shortages. Preliminary figures for 68 minerals show that production of 42 decreased, 25 increased, and one was unchanged. Production of 11 of 21 US-produced minerals was up. Noteworthy mineral events in 1980 included a copper industry strike, increased gold and silver prices, troubles in the iron ore and uranium industries, discussion about a US nonfuels mineral policy, and corporate interest in mining companies as merger targets. Recessionary conditions experienced by the Western world in 1980 resulted in a slowdown in new mine development, evident in the relative scarcity of major new base metal projects. This could lead to short term supply/demand anomalies within the next few years which, in turn, could have a significant effect on metal prices, according to Mining Magazine (Jan. 1981). World Mining (Sept. 1980) noted that US mining strength is in open pit operations. A much lower tonnage is mined underground and is centralized in trona, uranium, lead, zinc, molybdenum, potash and, to a lesser extent, copper. The most notable increase in new underground mines has been in Wyoming's trona district where new mines are being developed and production will increase, the magazine said.

Jan 5, 1981

By Robert E. Carver

Opaline clays from central and eastern Georgia are widely used as industrial and domestic absorbants, principally as insecticide carrier and animal litter. The clays are classified as fuller's earth, although they &e somewhat atypical of the group, since opal (cristobolite) is commonly the dominant clay-sized mineral. A preliminary investigation of absorption characteristics indicated that water vapor absorption (264 days) is' related to opal content as determined by x-ray diffraction peak height ratios. Ethylene glycol vapor absorption is related to montmorillonite content. Contact absorption of water is complexly related to surface absorption, porosity, opal content and montmorillonite content, and may be as great as 112% of the original sample weight. The most absorbent clays are highly porous (to 65%) and contain both montmorillonite and opal.

Jan 1, 1972

By M. J. Virnig, B. D. Boley, G. A. Wolfe, J. M. W. Mackenzie

A flowsheet for the recovery of nickel and cobalt from laterite ores has been developed which involves acid leaching followed by hydroxide precipitation of the metal values and then releaching of the hydroxide cake with ammonia. Investigations of the chemistry of extraction of nickel by LIX® 84-I and a developmental reagent, XI-84-IT, along with the physical properties of the organic phases are described. Based on these investigations, suggestions with regard to design of a solvent extraction plant and operating conditions are made.

Jan 1, 1999

By Fathi Habashi

METALS COMMONLY leached may come from one of the following sources: 1) Occurring in nature in the native state, e.g., gold, silver, platinum metals, copper. 2) Produced as by-product of a metallurgical process, e.g., gold, silver, platinum metals, selenium. 3) Produced by reduction of an oxide ore, e.g., copper, nickel. GOLD AND SILVER Cyanidation According to Mellor (1923) the alchemists of the eighteenth century knew that gold was soluble in aqueous solution of potassium cyanide, and the early jewelers probably utilized this fact in gilding. He also mentions that Scheele in 1783 and later Bagration in 1843 noted the solvent action of aqueous solutions of alkali cyanides on gold. Yet it was not until 1887 that the value of this observation was recognized, when MacArthur and Forrest (1887) made use of it in leaching gold from its ores. Since then, the process has spread to every gold and silver mining district in the world.

Jan 1, 1970

By Thomas P. Meloy

A brittle solid broken by crushing or impact, results in a mass size distribution curve having a straight line segment when plotted on log-log paper. Depending on the mineral, the slope of this straight line segment ranges from a maximum of one for materials like glass and quartz to values of one half or less. Theoretical derivations of the size distribution, such as the Gaudin-Meloy model, yield a slope of one and only one. When the Gaudin-Meloy model is modified to assume that not all cracks terminate on a preexisting surface, the new model predicts that size distribution slopes, depending on the type of brittle solid, will be less than one. There is a measurable physical parameter that will predict the slope. In addition the model predicts that particles from such a size distributions will have negative corners and peaks - indentations. Moreover the model predicts that particle shape will systematically change with decreasing particle size. Finally, this new physical model of comminution may be experimentally tested.

Jan 1, 1995

By P. Coleman, J. C. Kerkering, S. Iverson

A fatal accident may result when a dozer is driven over a hidden void in a coal surge pile and the dozer falls into the void, burying and suffocating the dozer operator. This type of accident was analyzed by researchers from the Spokane Research Laboratory of the National Institute for Occupational Safely and Health using inexpensive fault-tree programs that had been developed, for use on a personal computer. Fault-tree analysis is a systematic safety-analysis tool that proceeds deductively from the occurrence of an accident event to the identification of the root causes of that event. The analysis identified basic and intermediate events that led to the burial of the dozer and graphically depicted the interrelationship between the basic events as well as the intermediate events leading up to the accident. A sensitivity analysis on assigned probabilities showed which events had the greatest influence on dozer burial in a coal surge pile. Operational guidelines and engineering controls are suggested to decrease the probability of a burial event.

Jan 1, 2002

By R. C. Freas

Imported products and materials have been in the news over the last several years in a wide variety of industries. Certainly the mining and industrial minerals industry has not been exempt from this. Cement imports have received considerable attention in the press and a number of written articles. We are also seeing imported aggregates particularly along the gulf coast and east coast of the United states. We are now hearing increasing talk of bringing high brightness calcium carbonate from offshore sources into the U.s. domestic markets. This paper takes a look at the location of these sources, factors affecting their acceptance by U.S. industry and presents a general cost comparison of offshore and domestic calcium carbonate. In addition, the market response of U.S. suppliers and the impact of imports is also discussed.

Jan 1, 1989

By Lynn I. Kelley

Industrial-mineral production contributes on the order of CDN$1.5 billion per year to the economy of Saskatchewan, Canada. Potash is the primary industrial mineral produced in the province, followed by aggregate, sodium sulphate, salt, potassium sulphate, peat, clays, silica sand, calcium-chloride brine, and "clinker." Potentially economic deposits of kaolin, diamond, and building stone are under evaluation. All of the major deposits of commodities discussed here are located south of lat 56°30'N. Most of the locations are presented on Figure 1 POTASH Saskatchewan supplies approximately 30% of the world's demand for potash. Eight conventional underground mines and two solution mines produced an all-time high of more than 13 million metric tonnes of potash (KC1) (8 million tonnes K2O equivalent) in 1997, valued at over CDN$1.4 billion. All of the mines exploit the middle Devonian Prairie Evaporite. The four potash-bearing members of the Prairie Evaporite underlie much of southern Saskatchewan and extend southward into North Dakota and Montana and east- ward into Manitoba (Fig. 2). Halite and anhydrite separate the potassic members. The evaporite beds locally are interrupted by solution structures (anomalous ground). Some of the structures may be related to deep-seated tectonic features.

Jan 1, 1999

By R. K. Singhal, R. D. Lama

Underground coal mining systems have kept pace with developments that have occurred in other types of mining. A diversified group of machines are now available with high horsepower motors, built-in microprocessor technology, and numerous options to satisfy miners' needs in various geological environments. The results will be a greater degree of mechanization and recovery of coal from inclined seams, thins seams, and seams mined in lifts from shallow as well as deeper deposits. This article is based on a general suvey carried out by the authors to detemine the current status of mechaniztion and systems development in underground coal mining. It indicates that the next two decades will see increasing use of longwall mining, which has already reached a high degree of sophistication. Automation, remote control, and robotics are the key words of the future. Data transmission from underground to surface and over long distances will be almost routine. Many components of the high technology industry that are just being considered by the mining industry regarding equipment health and perform¬ance monitoring, quality control, application of expert systems, and computer networking will become a routine part of underground mining technology. Within the next 21 years, "manless" mining, first attempted about 25 years ago, will become a reality. References to any trade name are meant to aid understanding of the text and do not imply endorsement by the authors or their users. Current coal face developments Developments in underground mining equipment, its application, and associated technology have made phenomenal progress compared to those in other types of mining. Room-and-pillar systems, on one hand, and longwall mining, on the other, have sophisticated equipment at their disposal. Both of these systems have become highly productive, with output per manshift about 50% higher than that achieved a decade ago. Continuous miners continue to be the mainstay of room-and-pillar coal mining. Numerous developments, how-

Jan 1, 1989

By Ph. Vandebrouck

SUMMARY In August 1986, TRANSMANCHE LINK, a joint venture comprising the 10 companies who initially promoted the project, signed a contract with EUROTUNNEL for the design, construction and commissioning of the TRANSMANCHE fixed link for an amount of 4,5 billion dollars. On the French side, the work consists of digging three, 19km. long tunnels, of which almost 16 kms. are under the sea, up to the meeting point with the Tunnel works carried out by the British.. The tunnels are bored through chalk by 5 tunnelling machines, starting from one intermediate point at Sangatte near the coast: - Landward, they are drilled trough permeable strata of white and grey chalk. - Seaward, mainly through relatively impermeable chalk marl, but with the presence of water in faulted zones, or in grey chalk.

Jan 1, 1989

By L. A. Arrington-Webb

Forty-four states produced clay products during 1994 for a total value of $1.6 billion. This was a 3% increase in total tonnage and a 7% increase in value from 1993. Kaolin Domestic production of kaolin during 1994 was estimated to be 9.3 Mt (10.2 million st), according to the US Bureau of Mines (USBM). Georgia remained the leading producer with 7.5 Mt (8.2 million st), followed by South Carolina with 535 kt (589,000 st). Kaolin used as a paper coating or filler pigment accounted for 51% of domestic consumption. Other uses included grogs (14%), fiberglass (5%) and plastics (4%). A reclassification by an Alabama producer of fire clay to kaolin accounts for the introduction of kaolin used in grogs. This also accounts for the apparent decrease in the use of kaolin in paper from 60% in 1993. However, the actual amount of kaolin used in paper was the same.

Jan 1, 1995

By C. Zografidis

Environmental protection, economic prosperity and respect of the need for social equity promotion, constitute a prerequisite for any modern industry aiming to operate in a sustainable manner. The Natural Stone industry in Europe, a sector comprising mainly of SMEs, despite the fact that consists a dynamic extraction sector, often lucks the resources to apply novel techniques and management schemes towards achieving sustainable performance. I-STONE, an EU Integrated Project funded by the 6th Framework Programme, is aiming to contribute in the improved performance of the Natural Stone industry. A primary project objective is the re-engineering of the stone production chain, in order among others to considerably in-crease its efficiency and productivity, and minimise the amount of stone wastes disposed. The present paper, resulting from the research con-ducted on environmental management within I-STONE, is focusing on the use of sustainable indicators as a tool for the assessment of the stone industry?s performance. Based on Commission Decisions and reported studies, a list of indicators was selected and used within I-STONE, including environmental and socio-economic indicators. A set of selected environmental indicators were quantified based on operational data of a number of Greek and Portuguese quarries examined as case studies. The analysis indicated that an integrated strategy, including the application of novel operation techniques and equipment, waste minimization and systematic environmental monitoring and reporting, constitute key factors for the sustainable operation of natural stone industry.

Jan 1, 2007

Jurist, educator and historian Neil Reynolds will be the keynote speaker at the National Mining Hall of Fame's 11th annual induction banquet on Sunday, Oct. 11,1998 at the Pointe Hilton Resort in Phoenix, AZ. Reynolds is Municipal Court Judge for the City of Leadville, CO, home of the National Mining Hall of Fame & Museum, and a fifth-generation resident of the community. His family staked mining claims on nearby Mount Massive in 1862. Judge Reynolds is a fulltime faculty member at Colorado Mountain College, Chairman of the Lake County Historic Preservation Advisory Board and practices law in Leadville. In announcing the speaker, Board Chairman Richard Moolick said seven inductees into the National Mining Hall of Fame will join 138 mining greats previously honored in the annual ceremonies. This year's inductees will be enshrined by Thomas Falkie, president and chief executive officer of Berwind Natural Resources of Philadelphia, PA. Moolick also announced that Jeffrey Clevenger will be the master of ceremonies for the induction banquet. Clevenger is executive vice president of Cyprus Amax Minerals, Englewood, CO and president of Cyprus Climax Metals, Tempe, AZ. A cocktail reception at 6:30 p.m. will precede the black-tie (optional) dinner, to begin at 7:30 p.m. For additional information, contact Esther Mellott at 719 486 1229. Here are the biographies, then, of this year's seven inductees to the National Mining Hall of Fame & Museum.

Jan 1, 1998

By R. D. Lama

Coal mining is one of the major sources of methane release to the atmosphere by human industrial activities and is believed to contribute to -30% of the total methane emissions from industrial activities. In 1993, world saleable black coal production, attained almost 3.5 billion tonnes from which around 65% was produced underground. Coal in underground mines can contain high quantities of methane and some deep coal seams have methane content as high as 50 cubic meters per tonne of coal. Gas is re- leased during coal mining from the mined seam and in a higher degree from the neighboring unmined seams and gas bearing strata which are fractured as mining advances. This paper de- scribes a study which was undertaken to estimate the extent of methane emissions from coal mining in the world. Measured emission related data were collected from most underground coal producing countries in the world. The data included methane flows in the ventilation system, methane flows in gas drainage system, in-situ gas content, methane utilization and coal production. More comprehensive data were collected from a range of gassy and non-gassy Australian mines. Residual gas content of samples from run of mine were also measured. Using the Australian data, mathematical expressions were established to evaluate methane emissions as a function of coal production and in-situ gas content for other mines. These emission models were then used to evaluate the emissions for the countries or coal basins without measured emission data. Trends in methane emissions from underground mining for the year 2000 and beyond were also estimated.

Jan 1, 1997

By Robert A. Pimentel

Dust is still a major problem in increasing production from longwall faces. Over the last decade, significant improvements have been made in the development of techniques for reducing dust exposure on conventional and continuous sections. But virtually no improvements have been made in dust control on longwall sections. It is true, that there are many more continuous mining sections than longwall sections in the United States and that the number of workers overexposed on continuous miner sections is much larger than the number on longwall sections. However, the problem on continuous miner sections appears much easier to solve and, in fact, we believe that the techniques are available to get virtually all continuous miner sections in compliance. The problems on longwall sections are much more elusive. Also, the number of longwall sections in the United States is expected to increase during the 1980's. Thus, dust control on longwall sections remains a formidable and important problem. Companies operating longwall sections with a dust problem are faced with the tasks of having to quantify the various dust sources, of selecting proper techniques to reduce the problem, of implementing the techniques and of evaluating their effectiveness.

Jan 1, 1983

By R. O. Burt

Gravity concentration - the separation of minerals according to their relative density - is one of the oldest forms of mineral processing. Even though modern technology has developed a range of other processes, gravity concentration remains as one of the most important methods employed for mineral separation. The range of minerals recovered covers a wide spectrum, from andelusite to zircon, from coal to diamond, from gold to industrial mineral. The long history of gravity concen¬tration, along with a still imperfect understanding of the various mechanisms involved has resulted in a series of ingenious engineers developing, some¬times perfecting and sometimes rejecting, a wide range of equipment, suited for a variety of different duties. 'Selection' in the context of gravity separation, is primarily the choice of the right type of equipment for the separation in hand; 'sizing' of the correctly chosen unit is, more often than not, determining the appropriate number of units required to suit the throughput. The accent of this chapter will, therefore be 'selection'. A brief description of the major types of gravity concentration equipment will follow a discussion of the factors which determine the selection of the correct unit. CLASSIFICATION OF GRAVITY CONCENTRATION EQUIPMENT All concentration equipment has a primary function and a secondary function. The primary function is the efficient separation of the constituent minerals into two or more discrete phases; the secondary function is to effectively cause the discharge of these discrete phases into separate compartments (Aplan 1975). For maximum efficiency of operation, the forces which effect the primary function should not also result in the secondary function occurring; in such cases optimum operating conditions required for the primary function, separation, may have to be compromised to ensure reasonably efficient operation of the secondary function, product discharge. With gravity concentration, the primary function is effected by the relative movement of minerals of different density in response to gravity and one or more other forces, the latter often including the

Jan 1, 1986

By Mel J. Laurila

The application of on-line ash analyzers in coal processing has become widespread. However, the analyzers are employed largely in monitoring, blending or sorting applications. Just recently has work begun on using on-line ash, moisture and/or solids data for plant control; and even more recently for localized circuit or unit operation control. Process Technology, Inc. (PTI) has since 1990 placed several bulk coal and slurry analyzers in practice where Fuzzy Logic Control (FLC) loops are used to manipulate controllable variables in real time. This technology is now being advanced by PTI. Unit operations where FLC has been employed in feedback loops using on-line ash analyzers include: heavy media vessels, cyclones, concentrating tables and froth flotation. The design, implementation and improvements attainable in preparation plant control using on-line ash analyzers are outlined in this paper.

Jan 1, 1995

By J. S. Gardner, K. E. Houston, A. Campoli

INTRODUCTION Disposal of coal refuse is a costly and challenging problem facing the coal industry today. After the Martin County Coal Company slurry spill and the subsequent regulatory changes state and federal agencies are now beginning to require companies to justify new slurry impoundments. The authors have performed an analysis of different means of disposing of coal refuse for a major coal producing company located in the eastern Kentucky coalfields (the name of which will be withheld for the purpose of this paper). The company’s existing slurry impoundment is nearing its maximum permitted elevation and also an elevation where it may come in contact with abandoned underground workings. Due to the increased concern with underground mine works near slurry impoundments, additional consideration was given to raising the existing impoundment. Several other alternatives were evaluated, including but not limited to raising the existing impoundment, constructing a new slurry impoundment, constructing slurry cells, belt presses and others. This alternatives analysis was performed as part of a Section 404 permit for a valley fill and is currently being reviewed by the U. S. Army Corp of Engineers. All of the known possible alternatives were discussed in detail in the analysis. Due to the findings of the alternatives analysis, the company considers the engineered construction of the proposed impoundment to be the most favorable option of all the other alternatives evaluated, from both an economic and environmental standpoint. ALTERNATIVES EVALUATION FOR COALREFUSE/SLURRY DISPOSAL Background The company currently operates several deep mines and employ over 300 people and produces over 3.9 clean Mt/a (4 million stpy) of high quality, low sulfur coal. Currently, coarse refuse is belted to a valley fill, while, fine refuse is pumped to the existing impoundment. Coarse refuse is trucked to the existing impoundment as needed for construction purposes. The average recovery is approximately 50%; therefore, over 3.9 Mt/a (4 million stpy) of coal refuse must also be separated and placed.

Jan 1, 2003

By Ron Parks

High Pressure Grinding Rolls (HPGR) was introduced to the mineral processing industries in the mid-SO's as a tool for comminuting raw and processed materials. This tool made its an impact in the Cement Industry where it was used as a pre-grinder on existing ball mills, raw and finish grinding in a mill circuit and other various applications. This concept was a big success where the cost of power was high along with the desire to increase capacity. The HPGR reduced the power requirement and increased the capacity in the ball mill due to the finished product produced by the HPGR and the micro fractures in the coarse rock, which reduces the power required to finish grind the rock. This unit has found acceptance in many other industries including diamonds, iron and other selective applications. The diamond industry uses this tool for selective grinding purposes since the kimberlite rock is considerably softer than the actual diamonds. Therefore within a bed of material, kimberlite is crushed to fines and the diamonds are liberated and unharmed. The iron industry primarily uses this tool for concentrate comminution; however, there are installations using this tool as a pebble crusher and in an AG-pebble mill circuit.

Jan 1, 2000

By Peter Kowalczyk

The acquisition of submarine gravity data using airborne gravity technology is a practical reality. Ocean Floor Geophysics plans to deploy a free-swimming ROV based submarine gravimeter on a commercial basis in early 2009. The submarine instrument is a variant of the well-used GT-1A airborne gravimeter. Airborne gravity surveys are now routine. The primary factor controlling the accuracy of airborne gravimeters is the precision of the GPS measurement of vertical movement of the sensor platform. The gravity measurements along a flight line are the differences between the output of the gravimeter vertical accelerometer and the estimate of the aircraft vertical acceleration using the differential GPS system. The principle difficulty of moving an airborne gravimeter to a free-swimming submarine platform is the necessity to have an accurate real time estimate of the changing elevation and hence changing vertical acceleration of the platform; GPS doesn't work underwater and an accurate estimate of depth fluctuations to the necessary precision is difficult to acquire. It is interesting that the airborne gravity gradiometer technology, which competes with the airborne gravity technology, was first developed as a classified military application for use by missile submarines during the cold war. Gradiometers were developed for this application specifically to avoid this problem. A gradiometer does not require as accurate an estimate of its vertical position to make a useful reading- it measures gravity gradients, not the gravity field itself.

Jan 1, 2008