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By P. A. Delfosse

Numerous terms are used for rocks containing calcium carbonate so that confusion frequently occurs in the common language. Chalk and marble are two extremes among a wide variety of carbonate rocks including limestones, marls, travertine and other calcareous materials. We will deal mainly with the purest types of natural calcium carbonates which are widely used today in many industrial applications.

Jan 1, 1986

By Lennart Malmqvist

Decision-making in exploration deals with experience, knowledge, and sometimes faith, but very often financing and profit, mineral resource aspects, employment, and general political ambitions are parts of the scene. At one end of this spectrum, there is the prospector and his decision on the actual project. The exploration business now expands from its pioneering phase for the benefit of a single company to a wider spectrum which includes the benefit of the large mining consortium and a national development program. Its objectives are also to maintain employment and to favor long-term stability in a mining district or a mining company. The prospector then has new aspects and questions to consider such as, what to do in mining districts where there is a shortage of ore resources but there are still useful investments in mines, processing plants, etc. To analyze the exploration process, therefore, seems to be of great importance in a time of rapidly changing conditions. As in other areas of complex decision-making, for example, in the fields of investments, of production, and of the armed forces, computers most certainly have an important role to play in future exploration decision-making systems. However, we must first analyze our own business as closely as possible to find out what kind of information we need, i.e., why we recommend an exploration program as a good or a poor one. An important part of the debate about exploration is the case study. Case studies on exploration are few and most of those written are only about successful exploration programs. Where are the case studies of the failures and the not so successful programs? Every prospector knows that the majority of exploration projects fail. Consequently, the most important experience seems to be hidden in the failures.

Jan 1, 1979

By Robert W. Waytulonis

Miners working in underground mines where diesel equipment is used are exposed to exhaust pollutants. These include carbon monoxide (CO), carbon dioxide (CO,), nitric oxide (NO), nitrogen dioxide (NO2), sulfur dioxide (SO2), hundreds of different hydrocarbons (HC) and particulate matter. Evidence from animal inhalation studies and limited epidemiological investigations have led the National Institute for Occupational Safety and Health (NIOSH) to recommend that ‘... whole diesel exhaust be regarded as a potential occupational carcinogen ...’ NIOSH further stated that ‘... the excess cancer risk for workers exposed to diesel exhaust has not yet been quantified, but the probability of developing cancer should be decreased by minimizing exposure…’ The International Agency for Research on Cancer(IARC) reached a similar conclusion, saying that ‘... diesel engine exhaust is probably carcinogenic to humans.’ Before these declarations, there was insufficient evidence concerning the carcinogenicity of diesel exhaust. It was well known, though, that diesel exhaust caused less severe problems, such as headache, eye irritation and unpleasant odors. In 1988, a milestone was reached in the Mine Safety and Health Administration (MSHA) regulatory process. An advisory committee recommended a three-tier approach to regulating diesels used underground-approval of diesel equipment, safety and health. Diesel particulate matter may be specifically regulated. In addition, ambient air quality standards are being proposed that will establish a new standard for CO2 and lower the permissible exposure limits for the NO2, CO, SO2 and formaldehyde emissions that originate from diesels and other sources. Additional safety and emission restrictions are also proposed for diesel engines in coal mines. The goal of the US Bureau of Mines (USBM) diesel engine research program is to minimize the health and safety problems associated with underground diesel equipment use. Part of this program is focused on reducing exhaust emissions from diesel-powered equipment used in underground mines.

Jan 1, 1993

By Thomas E. Browne

The Electric Power Research Institute Energy Supply Program is developing coal supply forecasts. By coal supply forecasts I mean the future relationships between coal price and production levels. A representative supply curve is shown in Figure l. It will make the rest of my presentation clearer if at this point I give you some background about EPRI and the Energy Supply Program. EPRI is funded by the nation's electric utility industry to develop new technologies for the production and conservation of electricity. Most of the research is conducted by outside contractors. We participate in joint projects with the Department of Energy and other organizations. The Energy Supply Program is one of three "economic" programs. The other two are Energy Demand and Conservation, and Systems. The Systems Program's main function is to provide the means to integrate the output of the other two Programs. The primary function of the "economic" programs is to provide information pertaining to future energy prices, availability, requirements, etc. to the EPRI personnel planning R&D programs. A secondary role that is becoming more and more important is providing information of direct use to the electric utility industry. I should note that the results of all EPRI's contract work are available to the general public. A "Coal Supply Analysis System" is being developed for EPRI by Charles River Associates. To the extent possible it will draw upon existing work, but much additional work needs to be done in the area of coal supply economics.

Jan 1, 1977

By R. W. O. Kersten

The shrinkage method of stoping with pillar support has been used at Agnes Gold Mine since mining commenced. Until recently, rock instability did not have any detrimental effect on safety or production. Presently sill pillars are failing not only on the current production levels, but also in shallower old worked-out areas. The incidence of failure raises the question as to whether the pillar dimensions are adequate at the current working depths and what their size should be at greater depths. The effect of pillar dimensions on the economics of the mining operation is of paramount importance because of the amount of ore that can be left unmined.

Jan 1, 1982

By Rush H. Spedden

Antoine M. Gaudin was a vigorously creative man and throughout his career an internationally respected leader of his chosen profession of mineral engineering. To his professional colleagues and clients and to his former students he was both "Professor Gaudin," their wise, inspiring, and enthusiastic teacher, and "Tony," their warm and beloved personal friend. Thus, his teachings and his unique inquisitive-creative approach to problems live on and grow in the accomplishments of his students. Antoine Gaudin was born at the turn of the century in Smyrna, Turkey, where his father was general manager of a French-owned railroad. It was there that he spent his earliest years, literally in the shadow of classic marbles from diggings at the site of Aphrodesias, which his father had rediscovered. From this, Tony developed an appreciation of the arts. He eventually surrounded himself with art treasures; he reveled in the beauties of nature, and he cherished his choice collection of rhododendron and azaleas. His artistic traits led him to take up painting when his daughter, Elinor, sought his help in blending her tints for a water color. In typical fashion he was not satisfied until he had become adept with pastels in capturing the muted tones of distant landscapes and the technical properties of light and color. Unfortunately not many paintings were produced. His paternal grandfather was Marc-Antoine Gaudin, for many years secretary of the Academie des Sciences in Paris, and a well known chemist and mineralogist whose primary interests included the synthesis of precious stones. In an autobiographical sketch written in 1939, Dr. Gaudin recalled: "As a child I saw many of the original synthetic sapphires and rubies which my father had inherited. This, coupled with my father's avocation of mining ventures and archaeology, early decided that I would become connected with the mineral industry." One can speculate that the archeological activities of his father, the mineral systhesis experiments of his grandfather, and his own early studies of mineralogy and geology formed a base from which his special talents as an experimentalist were to develop. Laboratory research under Professor Gaudin's personal guidance was often an intensive, fast- moving, and exciting experience--especially to a new graduate student. First of all, Professor Gaudin was a highly skilled observer with seem-

Jan 1, 1976

By Thomas A. Wilson

Mountain Pass, California is located 96 km southwest of Las Vegas, Nevada, and has an exposed surface orebody within view of Interstate Highway 15. Mineral prospecting in this region dates back to about 1860 followed by the discovery and subsequent mining (1870-1895) of silver bearing veins on the north slope of nearby Clark Mountain. In contrast to the four lane divided interstate highway of today, all supplies needed for mining during this early history were transported by wagons from San Bernardino which is 320 km west. Many small lead mines were active in the area during 1917-20, and a small gold mine operated in 1941-42 within 100 m of the orebody presently being worked. In 1949 two prospectors searching for uranium with a Geiger counter discovered a radioactive vein outcrop at Mountain Pass. Further investigation revealed the presence of a large amount of a light-brown, heavy mineral to a depth of about 2 m. A sample of this unidentified mineral was submitted to the Boulder City, Nevada, U.S. Bureau of Mines where a spectroscope examination shoved high level rare earth oxides, carbon dioxide, and fluorine. These results indicated the mineral was bastnasite.

Jan 1, 1982

By A. D. Walters

Computer simulation models of preparation plant operations and cost analysis have been used to determine the profitability of individual coals. The model's input consists of raw coal size and washability analysis, operating cost data, and raw coal and clean costs. The model's output predicts yields, qualities, costs and profitability for an individual coal.

Jan 1, 1987

By Andrew W. Jenike

There used to be a time when bins were designed for total volume and placed in any available place of the plant. Poke holes were provided and feed was maintained by manual prodding, lancing, hammering, and by various mechanical flow-profiting devices. Little thought was given to what occurred inside the bins and why materials did not flow. Indeed, such mental effort was hard to justify while low-cost manual labor was plentiful, quality standards low, and rates of feed moderate. The past fifteen years have seen a drastic change in these conditions. We all know that labor for hard manual work is becoming unavailable at any wage, level. Standards of product uniformity are continuously rising. This uniformity is just as important in a fine ore feed to ball mills as it is in a cattle feed or in a flour mix. Rates of feed now frequently exceed 2,000 tons per hour per feeder. At that rate there is no time for, lancing or prodding. An efficient storage, plant contains a known available volume of bulk solid, and feeds it at the required time, at the prescribed rate, and without degradation of the product. A storage bin may also perform other functions such as blending of different grades, degasification of aerated, powders, isolation of different gaseous media. A contact bed of particles flowing by gravity in counter-current with a gas or liquid may be used as a continuous reactor. Gas or liquid pressures can be simply contained by, a sufficient head of flowing solid.

Jan 1, 1968

"Foreword by Lisa SchlinkSuperintendent, operations, Freeport-McMoRan Inc.,Green Valley, AZ, USAThe sixth annual Student Poster Contest hosted by the Mineral & Metallurgical Processing Division of the Society for Mining, Metallurgy & Exploration was held during the 2015 SME Annual Conference and Expo in Denver, CO. The contest had another record-breaking attendance of 31 entries: 27 graduate and four undergraduate. The universities represented were: Colorado School of Mines, South Dakota School of Mines and Technology, University of Kentucky, University of Utah, Southern Illinois University Carbondale, University of Wyoming and West Virginia University.The competition began with an extended abstract review by a panel of judges selected from MPD members. At the SME Annual Conference, all students displayed their posters, highlighting their research. The students with the top abstracts from the graduate and undergraduate divisions presented their research at the MPD Student Poster Session Wednesday morning. The panel of judges then provided tallied scores for the abstract, poster and presentation to determine the winners of the 2015 Student Poster Contest. The first- and second-place winners of both the graduate and undergraduate divisions received $1,000 and $500 scholarships, respectively. The third through seventh places received $200 each, and all other entrants received $100 each and were invited to join the MPD Luncheon.In the undergraduate division, Annette Hein of the University of Wyoming received first place for her research on “Solvent Extraction of Europium from a Nitric Acid Solution.” Second place went to Jennifer Galvin of South Dakota School of Mines and Technology for her research titled “Solvent Extraction of Neodymium Using PC88A.”In the graduate division, Caelen Anderson of the Colorado School of Mines received first place for his research titled “Fundamentals of Rare-earth Flotation Surface Chemistry: Hydroxamate Adsorption on Bastnasite”. This is Caelen’s fourth year placing in the top finisher. Second place in the graduate division went to Seyed Hassan Amini of West Virginia University for his research on “Ultra Clean Coal Production for the Solar-cell Industry.”The 2015 Student Poster Contest was chaired by Lisa Schlink (Freeport- McMoRan Inc.) and Emily Sarver (Virginia Polytechnic Institute and State University). The panel of judges included Aaron Noble (West Virginia University), Nick Gow (FLSmidth), Ren Bryce (Freeport-McMoRan Inc.), David Perkins (Derrick Corp.), Jim Metsa (Weir Minerals) and Scott Shuey (Newmont).A special thank you is extended to the sponsors of the MPD Student Poster Contest, to all the students who participated and to the panel of judges. Watch for more information on the 2016 MPD Student Poster Contest to be published later this year on http://www.smenet.org/mpd/ and in the November issue of Minerals & Metallurgical Processing."

Jan 1, 2015

The US Geological Survey (USGS) held a one-day workshop at its Denver, CO facility to inform the public of the status of its National Mapping Program. In addition, the agency wanted to obtain information from topographic map users on what their needs are. The agency wants to know what the topographic map user wants. The USGS faces the challenge of keeping up with the changing needs of the nation. In the last few years, the agency has changed dramatically to meet these needs. For example, the "new" USGS incorporates mineral-information specialists from the former US Bureau of Mines and also uses the expertise of former National Biological Service employees. These areas complement the agency's traditional strengths in mapping, geology and water re- sources. The stated mission of the USGS's National Mapping Division is to "meet the nation's need for basic geospatial data, ensuring access to and advancing the application of these data and other related ears science information f& users worldwide." To accomplish this goal, the USGS publishes topographic maps, including shaded-relief editions of areas of special interest (state maps and national parks); photo image maps; satellite image maps; geologic maps and hydrologic maps. The geologic maps include geologic quadrangle maps, oil and gas investigation maps and charts, and coal investigations maps. The familiar 7.5-minute series topographic maps are the most widely used. The 7.5-minute- (1:24,000-scale-) format mapping was begun in 1935.

Jan 1, 1998

By Aaron Jones, Guy Reed, Russell Frith

"In 2017, one of the international authorities on coal bursts, Dr. Chris Mark, published a paper entitled “Coal Bursts that Occur during Development: A Rock Mechanics Enigma,” in which several relevant technical issues were identified, the most pertinent being:i.whilst development coal bursts are commonly associated with geological faults, understanding which specific faults result in burst-prone development mining conditions and why, remains undefined.ii.conventional wisdom in relation to strong roof and floor geology of the coal seam might be limiting, based on certain burst examples in Colorado.iii. development coal bursts can occur without the local ground stresses being substantially elevated from their in situ levels.This paper outlines what is considered to be a credible, first-principles, mechanistic explanation for these three current development coal burst conundrums by reference to early published coal testing work examining the significance of a lack of “constraint” to coal stability and an understanding of how very specific structural geology and other geological features can logically cause this to occur in situ, albeit on a statistically very rare basis. This basic model is examined by reference to published information pertaining to the development coal-burst that occurred at the Austar Coal Mine in New South Wales, Australia, in 2014 and from the Sunnyside District in Utah, USA.The “cause and effect” model for development coal bursts presented also offers a meaningful explanation for the statistical improbability for what are nonetheless potentially highly-destructive events, being able to explain the statistical rarity being just as important to the credibility of the model as explaining the local conditions associated with burst events.The model could also form the basis for a robust, risk-based approach utilising a “hierarchy of controls” to the operational management of the development coal burst threat. Specifically, these include the use of pre-mining predictions for likely burst-prone and non-burst-prone areas, the use of the mine layout to avoid or at least minimise mining within burst-prone areas if appropriate, and finally the development of an operational Trigger Action Response Plan that reduces the likelihood of inadvertent roadway development into a burst-prone area without suitable safety controls already being in place."

Jan 1, 2019

By Paul H. Rylund

Substantial priming was a considered necessity for proper initiation of ammonium nitrate-fuel oil mixes as ANFO began to carve its niche in the mining industry in the latter fifties. Heavy priming accompanied the introduction of prills and oil to many blasting operations, large charges of high explosives were commonly used at the bottom, top and frequent intervals through-out the column. As the quality of ammonium nitrate improved and operators became more experienced, primer costs began to diminish. Increased experimentation continued with reduced primer costs a main objective. Cast primers were introduced and became accepted as an excellent companion for ANFO. Although the trend toward larger diameter boreholes became increasingly popular, emphasis on lower and lower priming costs continued. A primer was simply required to produce any type of initiation within the ANFO column to be considered adequate. Suddenly ANFO priming had digressed from excessive to marginal. Early experimental data developed at "test site" and laboratory locations indicated that ANFO had a tendency to react inefficiently in the initiation region of the column unless substantially primed. This was evidenced by the presence of unstable reaction rates detected with newly developed detonation velocity measuring equipment. These 10" order or "transient" velocities were believed to originate because of inadequate primer strength or a primer diameter to column diameter mismatch. How-

Jan 1, 1972

By Kal V. S. Sastry

Conventional iron ore balling circuits exhibit undesirable surging behavior which is known to result from uncontrolled occurrence of the mechanisms of nucleation, coalescence and layering. This study was undertaken to investigate the mechanism of pellet growth by layering. Several laboratory experiments have been carried out to delineate the effect of feed moisture content and feed quantity. This paper presents an analysis of the experimental results and a simple model to describe the layering process.

Jan 1, 1993

By D. M. Stephens

Feeder-Breakers were an unknown but much needed piece of machinery when U. S. underground coal mines started converting to more efficient belt haulage of the R.O.M. coal as compared to conventional methods that the 1950's offered. These simple electromechanical machines offered efficiencies in three areas: (1) they contained a surge hopper that allowed a "load' of coal to be dumped without delay; (2) this material was fed horizontally by a drag chain conveyor into a rotating carbide pick breaker that broke all oversize material into a beltable size, and (3) it fed this broken material onto the belt conveyor at a rate conducive to its design. Since its introduction, the Feeder-Breaker has evolved from that first low capacity, low breaking force machine to today's model capable of breaking materials up to 5 MOHS in hardness and having throughput capabilities exceeding 3,000 TPH with availability in the 90 percentiles.

Jan 1, 1985

By Peter Zhang, Daniel Su, Heather Dougherty, Jack Trackemas

"Longwall mining has a significant influence on gas wells located within longwall chain pillars. Subsurface subsidence and abutment pressure induced by longwall mining can cause excessive stresses and deformations in gas well casings. If the gas well casings are compromised or ruptured, natural gas could migrate into the mine workings, potentially causing a fire or explosion. By the current safety regulations, the gas wells in the chain pillars have to be either plugged or protected by adequate coal pillars. The current regulations for the gas well pillar design are based on the 1957 Pennsylvania gas well pillar study. The study provided guidelines for gas well pillars by considering their support area and overburden depth as well as the location of the gas wells within the pillars. As the guidelines were developed for room-and-pillar mining under shallow cover, they are no longer applicable to modern longwall mining, particularly under deep cover. Gas well casing failures have occurred even though the chain pillars for the gas wells met the requirements by the 1957 study.This study presents seven cases of conventional gas wells penetrating through longwall chain pillars in the Pittsburgh coal seam. The study indicates that overburden depth and pillar size are not the only determining factors for gas well stability. The other important factors also include subsurface ground movement, overburden geology, and weak floor, as well as the construction of gas wells. Numerical modeling was used to model abutment pressure, subsurface deformations, and the response of gas well casings. The study demonstrated that numerical models are able to predict with reasonable accuracy the subsurface deformations in the overburden above, within, and below the chain pillars, and the potential location and modes of gas well failures, therefore providing a more quantifiable approach to assess the stability of the gas wells in longwall chain pillars.INTRODUCTIONIn the eastern United States, abundant gas wells have been drilled through coal seams that are being actively mined by longwall mining. The existence of gas wells in the U.S. coal fields, whether active or abandoned, have caused many issues for longwall mining. First of all, any gas well in the mining area has to be located by all possible means. Secondly, the gas wells within longwall panels have to be plugged, as cutting through gas wells will allow natural gas to flow into the active longwall mines. On the other hand, the gas wells within longwall chain pillars or barrier pillars can be left in place if the wells are protected by properly designed pillars."

Jan 1, 2019

By Dan Nilsson

Open pit mining is the strong sector of the American mining industry. In the middle of the 60's. 17-18% of the ore in metal mines was mined with underground methods. From the middle of the 60's to 1980 the production in open pit metallic mines increased from about 400 to close to 600 million short tons while at the same time the underground mine production decreased a little, from about 90 to about 80 million tons. Less than 15% of the ore prodction now come from underground mines. Large amounts of waste rock were also handled in the open pits. In the middle of the 60's about 600 milion tons were handled, in 1980 1,200 million tons were moved. This means that the average stripping ratio increased from about 1.5 to over 2.0 tons of waste rock per ton of ore, figure 1.

Jan 1, 1983

By E. A. Noble

In the Western Coal Region, successful reclamation of surface-mined areas includes the protection of groundwater sources. To accomplish this, a complete understanding of the geohydrology of the affected area is imperative. Successful mine design also calls for careful attention to geohydrology. Because the Western Coal Region is semi-arid land used mainly for farming and grazing, groundwater is a particularly sensitive topic. It is especially sensitive where the lignite scheduled for mining is itself the aquifer supplying the farms and ranches. Such is the case throughout much of the Western Coal Region, particularly where there are no near-surface sand and gravel aquifers that are commonly found in the glaciated portions of the Region. Just as mining can adversely affect groundwater supply, so can groundwater adversely affect mining. Mine flooding and highwall instability are examples of this. But, mine operators must realize that procedures they use to remedy geohydrologically-related mining problems can have a dramatic effect upon ground- water conditions in areas adjacent to the mine. A logical precaution is to require the acquisition of complete baseline data prior to making the first cut. We recommend that the mining plan not only incorporate the reclamation plan, but that they be developed as one plan.

Jan 1, 1976

By J. A. Herbst

Successful transitions from micro- to macro-engineering are the keys to effective technology transfer between research and development organizations and industrial end users. At the same time, it has proven to be one of the most difficult tasks that the minerals industry has had to manage. Typically, developers of fundamental information concerning how mineral processing subsystems work have been academics and government scientists. These are the individuals giving the most important input to micro-engineering models that can benefit industrial operations. Publication is the usual route for "attempting" to transfer this technology to the end users. Unfortunately, with such publications, very little direct communication occurs concerning real industry needs or the future steps required to make the particular micro-engineering model useful. In the past, the industry has relied on in-house R&D groups and plant metallurgists to "translate" publications, to provide useful macro-engineering tools for plant applications. To some extent, engineering companies have also been asked to serve this function. However, these firms have been rather ineffective in this area since their conservative nature has caused them to look rather suspiciously at new technology. This approach to technology transfer has worked, albeit clumsily, for the last several decades. This communication system is now on the verge of total collapse due to conditions of the minerals industry. Mining companies can no longer afford the significant overhead expenses of specialized technical staffs. Universities are finding it extremely difficult to interest US students in mineral engineering programs, and funding for such programs is weak. Faculty members involved in micro-engineering research today tend to focus on pure (non-application-oriented) research.

Jan 1, 1992

By T. V. Durkin

Approximately 1,390 t (44.7 million ounces) of gold have been produced in South Dakota since 1875. South Dakota's mining laws attempt to strike a balance between economic development and environmental protection by promoting mining as an industry while requiring prevention of pollution and reclamation of affected lands to a beneficial use. The mining laws have evolved since their inception in 1971, especially in response to gold mining. The laws have remained flexible to meet changing regulatory needs. Gold production has continued relatively unabated, even in the face of public scrutiny, two mining moratoriums, and isolated environmental problems. The department's system of "one-stop-shopping" for environmental permits streamlines the permit process, fosters quick resolutions to compliance problems, and helps keep enforcement actions out of the courts. Specific case histories at heap leach mines within the Black Hills are presented.

Jan 1, 1998