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By V. L. Brant

The estimated total energy demand for the U. S. is 60 quadrillion BTU for 1970 and is expected to more than double by the year 2000. Today the energy crunch is here. It is evidenced by brownouts to conserve electrical energy, and the shortage of gas and oil. Many such headlines, including suggestions for energy rationing, are in the news today. Paradoxically we have an abun¬dant source of energy in the form of coal. Energy consumers, however, are geared to use fuel in other forms. It is the intent of this presentation to discuss processes under development for conversion of the energy contained in these vast coal reserves to more usable forms. Coal conversion to synthetic fuels should be of particular interest to those engaged in mining. Coal consumption in a single conversion plant is expected to range from 10,000 to 40,000 tons per day. Plants will be located at the mine mouth and will operate continuously 24 hours per day, seven days per week. Further, many such plants will be needed., For example, looking at natural gas only, the supply/demand gap is estimated to reach 13 trillion cubic feet per year by 1985. Assuming that gas from coal conversion were to fill only 101, of this gap, 15 plants producing 250 MMSCFD would be required. These plants would consume about 90 million T/Y of coal or 135 million T/Y of lignite. It will indeed be a challenge to mine, suitably prepare, and transport coal at these projected volumes without interruption. Many ideas have been conceived for better utilization of coal and these are in various stages of development. Those supported by public money are covered by the Annual Report of the Office of Coal Research (OCR), Department of Interior. The two processes to be discussed, the Consolidation Coal Company's (Consol) C02 Acceptor Process (1)(2)(3) and The Pittsburg and Midway Coal Mining Company's (PAMCO) Solvent Refined Coal Process (4)(5) are both sponsored by OCR.

Jan 1, 1970

By Robert L. Mentch

CADMIUM is one of the metals apparently destined to remain relatively scarce. The en tire supply of primary cadmium is recovered as a byproduct, concurrently with the treatment of ores of other metals. Development of the cadmium industry is attributed to metallurgical improvements in the zinc industry; output depends almost wholly upon zinc production. Cadmium is a metal of specialized uses where its superior performance has developed a strong, expanding demand. The supply, however, has been relatively unresponsive to price because of its byproduct nature. Cadmium's outstanding properties would assure it a manyfold greater market if more were available at lower prices.

Jan 1, 1958

By Liping Yu Che, Xiaotie Wang, Mingli Cao, Jizu Yongfu Yuan

"It is difficult separating fluorite from Ca, Ba, Si intergrowth minerals than simple from Si, using common reagents such as combination of oleic acid or paraffin soap and water glass, but the finest quality fluorite concentrate whose grade is over 96%F must be required in chemical plant.This paper studies the flotation process of native fluorite from calcite, barite and silicate minerals whose flotation properties is similar to fluorite, using new effective collector H602 and new depressor S602 that is cheaper in cost, and describes the flotation properties. In order to determine optimum flotation separation condition, the effect of pulp pH, pulp temperature, pulp density and the effect of dosage of reagents on flotation were investigated and the flotation result was provided by oleic acid collector and the results of collector H602 were compared with those of collector oleic acid in the test. The test result of ore samples shows that at moderate pulp pH values (10.5-11.5) and other moderate technical conditions, the fluorite mineral can be obtained by new reagents and the rational reagents combination. The conclusion is 98%F of fluorite concentrate can be obtained, using the combination of H602 and S602 and only 5 steps in techniques. The paper discusses the mechanism of the flotation separation of fluorite mineral from intergrowth minerals."

Jan 1, 2003

By R. M. G. Machunter

Computer models of metallurgical circuits are extensively utilised in design, and prediction of overall plant separation performance. As always, in the final optimised flowsheet design there is a compromise between the recovery of values and grade of the circuit output. This paper mathematically examines various circuit options for the generation of a heavy mineral concentrate from a generic mineral sands wet concentrator plant. Based on data derived from testwork, any particular mineral sand has a unique release curve describing the separation performance of the heavy mineral suite. Models are constructed that combine particular stage output streams as feed to other stages in various configurations. The ramifications of each option are discussed and reasons why one particular option is selected over the others examined.

Jan 1, 2005

By M. Viljoen

South Africa has produced more than a third of the total gold mined throughout history and remains a major although, until recently, no longer the largest producer of gold. South African gold production peaked in 1970 with an output of 1 000 t, a major component of the western world?s gold production, with the development of the country?s economy having been based largely on this mineral wealth. The costs and difficulties of increasingly deep-level mining, coupled with increasing labour costs and the low gold price until relatively recently, have seen production fall steadily since then, with the closure of many mines including those of the Central Rand Goldfield in the mid seventies. Thus in 1998, only 464 t were produced, with 342 tons being produced in 2004. In 2006, 275 tons of gold were produced and after more than 100 years was the last year as the world?s largest gold producer. In 2008 gold production was 221 tons, making South Africa the third largest gold producer after China (292 t) and the USA (234 t). Gold production would have been lower if it had not been for massive tailings dam retreatment operations that started in the late seventies, including in the Central Rand Goldfield. Mining of a remaining deep and lower grade shallow resources has now also become a major focus and has recently lead to a rebirth of reef mining on the Central Rand Goldfield.

Jan 1, 2009

By A Hocking, S Henderson

Commonwealth of Australia (2016) defines rehabilitation as comprising “the design and construction of landforms as well as the establishment of sustainable ecosystems or alternative vegetation, depending upon the desired post-operational land use”. For open cut coal mines in Queensland and New South Wales, the question of how to apply this intent to pits at mine closure is repeated for hundreds of individual pits. In EISs, closure plans and public discussion, assorted treatments are proposed to rehabilitate pits. While some aspects of final voids have been intensively studied, there is little guidance on how to choose a final void treatment option that delivers the optimal outcome against rehabilitation goals. For example, in the Bowen Basin and Hunter Valley commonly proposed rehabilitation actions include reducing the angles of pit walls; however, with few voids successfully rehabilitated to date there is limited understanding of what different wall slopes will achieve.CITATION:Henderson, S and Hocking, A, 2018. A decision framework for comparison of coal void rehabilitation options, in Proceedings Life-of-Mine 2018, pp 127–130 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 25, 2018

By R. L. Virta

Six companies mined fire clay in Missouri and Ohio during 2004. Production, based on a preliminary survey of the fire clay industry, was estimated to be 398 kt(438,700 st), valued at $9.81 million. This was slightly less than the production and value figures from 2003. Missouri was the leading producer state. It accounted for more than 70 percent of the U.S. production. Consumption Domestic producers sold or used fire clay primarily for refractory applications. This application accounted for 79 percent of the market. Refractory products made using fire clay include firebrick and block, grogs, high-alumina brick and specialties, refractory mortars and mixes, and saggers.

Jan 1, 2005

By Jesse H. Auvil

In January of 1966, during the annual session of Georgia's General Assembly, Representative Paul E. Nessmith of Statesboro, Georgia, walked into my office and asked me what I thought of the advisability and feasibility of a law which would require the mining operators to reclaim their mined out lands. My answer to him was, as a one time mine superintendent and operator, that I probably would not think very highly of the added cost which reclamation would impose on the operation; but that since assuming the job of Chief Geologist and Assistant Director of the Georgia Department of Mines, Mining and Geology, and in retrospect, I could recommend it very highly, particularly in view of the increased pressure being applied by the Federal government along these lines. I stated then and still emphatically state that this sort of administration should be done on the State level rather than the Federal level. He asked me if I would conduct him on a tour through some of the mining country in which I had worked and to this I readily agreed. The result of this trip was that he was adversely impressed by the devastation which the mining operations had wreaked on that area of middle Georgia along the fall line known as the kaolin belt. Very little except talk was done for the remainder of 1966.

Jan 1, 1970

By Vinícius Cardoso da Rocha

Frente ao cenário industrial competitivo, o emprego de fluxantes em lingotamento contínuo de aços permitiu o aumento da produtividade e a redução das perdas metálicas por defeitos superficiais. Neste estudo, avaliou-se a aplicabilidade de dois tipos de fluxantes para produção do aço SAE 1046 Mod. Os fluxantes foram testados quanto ao desgaste da válvula submersa, frenagem (atrito) na interface metal/molde e rejeição dos produtos de lingotamento devido à presença de defeitos superficiais. O fluxante teste apresentou taxa de desgaste de válvula submersa de 2,2 mm/corrida, frente ao fluxante padrão com 0,8 mm/corrida. Entretanto, o fluxante teste demonstrou bons resultados quanto à lubrificação do molde, reduzindo a frenagem (atrito) entre o metal e molde e, consequentemente, melhorando a qualidade superficial do produto de lingotamento. A rejeição dos produtos por defeitos superficiais reduziu 47% com o fluxante teste.

Aug 16, 2017

By Z. Yu

Low-rank/oxidized coals respond poorly to oil agglomeration. Emulsification of kerosene in the presence of surfactants dramatically reduces the size of the kerosene droplets. While this dramatically reduces the amount of oil that is required for efficient agglomeration (down to 0.25-0.5%), more importantly, the surfactants entirely change the electrokinetic properties of the oil droplets and thus the interaction between oil droplets and coal particles. Consequently, kerosene cationic emulsions can efficiently agglomerate oxidized coal particles. The agglomerates obtained in such a process can still be recovered by screening. Surfactants can affect fine coal filtration very profoundly when used to emulsify the oil which is utilized to agglomerate coal prior to its filtration. This sequence is much more logical than the use of flocculants - highly hydrophilic polymers - as filtration additives to aid dewatering of flotation concentrates. Although such polymers flocculate coal particles, they also render coal surfaces hydrophilic and make reduction of the cake moisture content difficult.

Jan 1, 2000

By Gustavo Eduardo Praes

A Samarco Mineração S.A., nos últimos anos estudou diversas alternativas para a substituição dos combustíveis fósseis por combustíveis renováveis (Biomassa) em seus fornos de pelotização tipo “Traveling Grate” (grelha móvel). Avaliou-se o uso de carvões vegetais, de eucalipto e de capim elefante, em substituição total ao antracito na composição da mistura. Estudou-se gaseificação em planta piloto, foi realizado um modelamento computacional do uso de gás de síntese e a comparação com os combustíveis tradicionais utilizados em fornos de pelotização de grelha móvel da Samarco. Os trabalhos iniciais foram realizados em escala de laboratório (Pot Grate). Em 2014 foi realizado um teste industrial, com um combustor de biomassa piloto acoplado ao duto que direciona o ar quente para a região de secagem ascendente do forno 02 da Samarco Mineração S.A. O teste ocorreu entre 27 de janeiro a 21 de julho de 2014. Realizou-se uma avaliação detalhada da engenharia deste sistema e de seus impactos no forno de pelotização. O combustor consiste em um sistema para queima de biomassa, o qual gera os gases quentes a serem introduzidos no sistema. Dependendo da configuração, o sistema poderá elevar a temperatura dos gases de secagem em até 75°C, quando comparado a uma situação de referência.

Aug 16, 2017

Historically, mine ventilation practices as it was referred to then and which was enforced by legislation of those days, focused primarily on the conditions in the working place and little attention given to actual exposures of workers to contaminants in the working environments. With the advent of the Leon Commission of Inquiry into Safety and Health in the South African Mining industry in 1994, findings in the report indicated that more attention should be given to occupational health of workers. The upshot of this report resulted in the promulgation of the new Mine Health and Safety Act (MHSA) with certain sections of it devoted to all the aspects of occupational medicine and occupational hygiene. This paper describes the present situation with regards to statistics on occupational hygiene performance and compensation paid out to persons who have contracted occupational diseases, as well as the way forward in terms of legislation implemented in September 2002 on the chronic and acute issues affecting the mining industry in SA.

Jan 1, 2003

By G. Guzman, L. Sevilla, M. Botz

"Newmont Mining Corporation operates the Yanacocha mine in Perú and the gold milling section of the property includes a Sulfidization-Acidification-Recycle-Thickening (SART) plant to remove copper from pregnant leach solution. Since its commissioning in 2008, the plant has been intermittently operated as needed to remove copper upstream of a carbon adsorption circuit. However, starting in 2015 Newmont expects the plant to operate on a more continuous basis in response to higher copper ores that will be processed in the gold mill. In anticipation of this, Newmont conducted a campaign in May 2014 with stockpiled high-copper ore to evaluate performance of the SART plant with elevated levels of copper in feed solution. Results from the campaign demonstrated the SART plant is capable of efficiently treating high-copper leach solution. During the campaign, leach solution copper levels ranged from about 100 to 700 mg/L, and copper removals ranging from about 56% to +99% were achieved. The median copper removal efficiency observed during the campaign was about 94%. The primary plant modification determined necessary following the campaign was the need to improve consistency with sulfide dosing. INTRODUCTION Copper removal from cyanide leach solution can be affected through the addition of sulfide at acidic pH to precipitate copper sulfide as a solid. There has been renewed interest in the process in the past several years due to the increasingly common issue of high copper levels in cyanide leach solutions. The term Sulfidization- Acidification-Recycle-Thickening (SART) is used as an acronym for the process according to the primary unit operations utilized. At a pH of approximately 4.0 to 5.0, the addition of soluble sulfide to a copper-bearing leach solution will result in the precipitation of copper sulfide (Cu2S) solid. The overall acidification and sulfidization reaction is (assuming the use of sulfuric acid for pH adjustment): 2Cu(CN)3-2 + 3H2SO4 + S-2 ? Cu2S(s) + 6HCN(aq) + 3SO4-2 The above reaction is written relative to the copper-cyanide complex 2Cu(CN)3-2, though analogous reactions also take place with the other common copper-cyanide complexes Cu(CN)2- and Cu(CN)4-3. Sulfide in the above reaction (S-2) is normally supplied as sodium hydrosulfide (NaHS) purchased in solid or concentrated liquid form. Two characteristics of this reaction that are beneficial to a leaching operation are: 1. Copper is removed from solution as Cu2S (synthetic chalcocite) solid, which can then be sold to a smelter for its copper value. 2. Cyanide that is complexed with copper in the leach solution is released as free cyanide, thereby regenerating cyanide that can be recycled to the leaching operation for continued use."

Jan 1, 2015

By Bruce Notthup

Using a Three Dimensional Laser Profiler, persomrel from Austin Powder were able to determine drilling patterns for use in underground mine Room and Pillar blasting operations, The faces had got out of alignment, causing concave faces across the 100 feet wide, 28 feet high tunnels. This was leading to poor drilling and poor blasting results. By profiling the faces, modifications could be made to the drilling pattern to help gradually straighten the faces. The Laser Profiler was also used to check the accuracy of collaring the holes and also perform post blast surveying of the positions of the bootlegs. This allowed recommendations to be made to improve drilling operations at the face. In addition, other volumetric calculations could be performed using the systems’ surveying software, all a lot more easily and quickly than by standard methods.

Jan 1, 1994

By G. C. Presley

Estimated domestic production of pumice and pumicite in 2004 increased about 23 percent since 2003, according to the U. S. Geological Survey (USGS). The USGS estimate of domestic production of 687 kt(757,000 st) for 2003 turned out to be 870 kt (959,000 st)of actual production. The USGS estimated the value of pumice and pumicite sold or used in the United States to be $26 million in 2004, up $4 million from the value in 2003. There was an estimated decrease in the mine, or mill, average price to $24.14/t ($21.90/st) in 2004 from $25.19/t ($22.85/st) in2003.

Jan 1, 2005

By M Foster

The new environmental legislation of 1986 was left incomplete and to date remains so. The 'missing' process by which environmental consideration should be applied was never embodied in law and has predisposition to a wide interpretation. The Resource Statutes which govern land use and development place demands on the environmental process without that definition. The Resource Statutes are themselves under review by Government. There is a new Government Department of Conservation. It is still in its early days and facing a challenge to compose its role as a steward over large tracts of land holding significant marketable resources, animal, vegetable, mineral, and abstract. It has also taken over numerous consent and advocacy roles in legislation beyond its own empowering Act. Enter the mining company, anxious if not able to get an easy passage for consents to prospect and mine, then at least to have a clear path to tread to get there, within a fixed time period. Whichever options appear available to process environmental approvals, public participation is that being favoured most by the regulatory bodies. Where a public notification of consent applications is mandatory, public participation should lead to the fastest track available.

Jan 1, 1988

By J. F. T. Agapito, L. J. Gilbride

High horizontal stresses were recognized to impact roof stability more than 60 years ago. Since then, numerous measurements associated high horizontal stresses with difficult ground conditions. This paper presents case histories illustrating the practical usage of roof stress determinations for helping assess stability, not only in the case of high horizontal stresses but also of low stresses. Examples are given of high stresses associated with faults, mine design changes, quantification of stress shadow effect, and anistrophy. The paper concludes with a comparative evaluation on the effect of various stress fields on ground support requirements.

Jan 1, 2002

By P. Albert Carpenter, Wallace B. Howe, Michael N. Greeley, E. C. Bingler, Gilbert R. Eakins, Christy Bell, John Callahan, Gary B. Glass, T. J. Crabs

Although gold's market price dropped considerably from 1980's all time high, exploration for the precious metal remained a particularly bright spot last year, especially in the western US. For example, in Nevada-the nation's largest gold producer-further exploratory drilling at Louisiana Land & Explorations Co.'s deposit at Round Mountain and Newmont Mining Corp.'s find near Carlin resulted in sharp boosts in estimated reserves at both sites. Louisiana Land said its deposit is well on the way to being one of the largest gold reserves in the US. Based on further drilling, Newmont said its Gold Quarry property near Carlin could now produce 4.7-6.2 t/a (150,000-200,000 oz/ year). Reserves at Newmont's two properties near Carlin and a third property in southeast California are reportedly at least 218 t (7 million oz), up from the previously announced 128 t (4.1 million oz). Gold exploration activities were brisk in many other states, including a noticeable effort to explore and reopen dormant properties. Although the return on investments didn't appear as favorable last year as they did in 1980, the gold price was apparently sufficient to spur healthy exploration activity. Outside precious metals, market conditions, and subsequent exploration activity, appeared much more bleak. In the molybdenum market, for example, prices continued to slide, and Amax Inc. tightened its exploration budget. (Amax supplies 60% of the domestic market and 45% of the world demand for molybdenum.) The company spent 16% less on exploration during the first six months in 1981, compared to the same period in 1980. Copper and many other base metal producers appeared in similar straits throughout the year. Uranium exploration activities continued to suffer last year also due to depressed market conditions. Among others, Gulf Minerals Resources and Amoco Minerals Co. suspended uranium exploration activities in the West. Despite current unfavorable conditions, some companies continue uranium searches, confident that market conditions will rebound. On a brighter note, interest in exploring for some industrial and strategic minerals appeared on the upswing last year. Minerals used for oil and gas drilling, such as barite and special sands, were especially noteworthy. In geophysical activity, significant developments were achieved for electromagnetic techniques in both frequency-domain and time-domain systems. Geophysical logging activity declined due to decreased uranium exploration, and computer hardware continued to impact the way mining geophysical data are being acquired. Many presentations and papers were given last year to help exploration geochemists develop new techniques to locate concealed ore bodies. Among techniques described were statistical and computer modeling for enhancing anomalies over blind deposits.

Jan 5, 1982

By O. Alvarez-Campos

Two porphyry copper orebodies, the North and Central MM orebodies, have been found through regional and structural geologic works, about 5 Km south of Chuquicamata, under a gravel bed of approximately 100 m and in the west side of the West Fissure. The mineralization is emplaced in a coarse granodioritic porphyry, predominantly with sericitic alteration. In the North MM ore-body, with 200 million metric tons of 1.0% Cu, the mineralization is mainly chalcopyrite, bornite, digenite and molibdenite. In the central MM orebody, with 700 million metric tons of 1.3% Cu, there are large veins of enargite, chalcocite and bornite, the last one increasing in depth, separated by chalcopyrite and pyrite zones; in these veins there are interesting gold and silver values. Both orebodies have an upper enrichment of chalcocite and covellite, with pyrite envelope. According with these characteristics, the MM orebodies could he the upper part, with sericitic alteration, of the Chuquicamata porphyry copper system, displaced by the West Fissure system movements, but we couldn't eliminate the possibility that MM can be a new orebody, different of Chuquicamata.

Jan 1, 1993

By J. A. Haskin

The Engineering Department at Flin Flon has the following responsibilities: 1. Underground Surveying. 2. Open-Pit Surveying and Supervision of Blasting. 3. Mine Geology and Examination of Prospects. 4. Design of Plant Additions and Improvements. 5. Miscellaneous Field W ork, Reports, etc. The entire surface plant, as well as the underground workings, are located by co-ordinates based on a triangulation system covering an area approximately one mile long by one-half mile wide. The origin of this system and one end of the base-line is the southwest corner of Township 67, Range 29, west of the Principal Meridian. The bearing of the base-line was determined from the township boundary, which runs true north, so that all other bearings are almost astronomical. This is a great convenience when our surveys must be tied to mineral claims, rights-of-way, and land subdivisions. As the base-line extends across Flin Flon lake, its measurement across smooth ice was simple and accurate. The length, slightly over 1,600 feet, has been adjusted for the temperature and tension of the standard tapes used and checked sufficiently to ensure a maximum error of 1 : 15,000. Each angle was repeated ten times, but as no special refinements were used, errors of as much as four or five seconds are possible. The elevation of the origin of the triangulation system was approximately 1,050 feet above sea level. The use of this true elevation in our surveys would have resulted in negative elevations underground as soon as the mine reached a depth greater than 1,050 feet. To avoid this complication we therefore added 4,000 feet to this elevation. The collar of the Main shaft, for example, which is actually 1,072 feet above sea level, appears in our records as at elevation 5,072. Underground surveying, which follows standard practice, is done by two mine surveyors who share three helpers. The meridian is taken underground from two wires hung in either of the two vertical shafts.

Jan 1, 1935