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By Doris M. Hyde

Belize remained relatively insulated from the social and political turmoil that affected some of its Central American neighbors. This stability encouraged new foreign investments that assisted the economy, especially in tourism and agriculture. The mineral sector remained limited to construction-oriented materials. Oil exploration efforts continued by the various concessionaires.

Jan 1, 1987

By Jeffrey A. Pontius

The Cresson gold deposit is in the southcentral portion of the Cripple Creek mining district in central Colorado (Fig. 1). The deposit is hosted by a series of 32 Ma (Kelley, 1995) felsic to mafic, alkaline volcanic rocks that were deposited in a diatremal environment. Mineralization in the Cresson deposit is structurally con-trolled. It occurs as disseminated and vein type. Gold deposition is closely associated with potassium-pyrite metasomatism and quartz-telluride vein development(Pontius, 1992). The Cresson deposit is owned by the Cripple Creek and Victor Gold Mining Co. (CC&V), a joint venture between Pikes Peak Mining (67%) and Golden CycleGold (33%).

Jan 1, 1996

By Tianrui Xu, Chaohong Liu, Bangqing Ding

The authors were responsible for a series of large scale multiple chamber charge blasts conducted in the granite mountain area for making construction space on the southeast sea coast in China during 1993-1996. This paper describes the blast design and damage control of one mountain blast 320m in length and 280m in width in the vicinity of two wharfs and a dam. In order to obtain better rock fragmentation and muckpile, the explosive charge should be well-distributed in the mountain. The charge pattern, therefore, was designed with mainly 5 rows of tunnel charge in regular terrain in combination with a chamber charge in irregular topography area and the maximum burden was limited to be less than 38m. In order to protect the dam and wharfs the firing sequence was carefully arranged in 29 intervals and the distance between different charges of the same delay to the dam or wharf was taken into account as an additional delay interval based on the difference of p-wave propagating times. The maximum charge fired in an interval was also limited to less than 34t explosives through dividing the larger charge by a stemming deck.

Jan 1, 1998

Study on Rational Process Flow Sheet for Beneficiating Low-Grade Cu, Mo, Bi, S, W Polymetallic Ore

Sep 13, 2010

By R. Siwik, N. K. Davé

"The national reactive tailings (RATS) program is a co-operative industry-government effort to develop practical techniques for closure of reactive tailings areas. This paper summarizes the RATS program objectives and areas of research, and details the Noranda/CANMET project on the Waite Amulet tailings.Geophysical and biohydrogeochemical investigations were carried out at an inactive copper-zinc mine tailings site, Waite Amulet, in Noranda, Quebec. Geophysical investigations consisted of seismic, electromagnetic conductivity and electrical resistivity surveys to determine the thickness of the layers above bedrock and to map conductivity variations within the tailings and the immediate outlying area. Biohydrogeochemical investigations consisted of installing multilevel piezometer nests to determine groundwater flow patterns and porewater chemistry, obtaining solid core samples and characterizing for physical, chemical and mineralogical parameters, and iron oxidizing and sulphate reducing bacterial counts.The geophysical survey indicated a bedrock ridge extending under the tailings from the northeastern outcrop which may act as a porewater boundary layer. The survey also indicated a 2 to 20 m clay layer underlying the main tailings dam. Preliminary results of the saturated zone porewater chemistry have indicated three major zones of high electrical conductivity varying between 1,000 to 12,000 µs and pH between 3.4 to 8. Lower pH and high metal and sulphate concentrations were obtained in a shallow zone near the water table. With depth, the concentration of metal and sulphate ions decreased and pH increased below the water table. The underlying clay layer is relatively impervious -and most of the seepage from the tailings is probably exiting from the sides of the impoundment dam."

Jan 1, 1987

By G R. Dickens, N H. S Oliver

The genesis of giant hematite ore deposits in northwest Australia remains a contentious topic in part because key evidence supporting a unifying genetic model has not been found at all deposits. In particular, several papers have proposed that carbonate replacement of silica layers in banded iron formation (BIF) by basinal brines is a requisite first step toward ore formation. This initial hypogene stage is inferred primarily from the presence of silica-poor, carbonate-rich rocks found below ore and along normal faults at the Mount Tom Price and Giles Mini deposits. However, until recently such rocks have not been identified at the largest martite-microplaty hematite deposit, Mount Whaleback. In this study, samples of the upper Mount McRae Shale are examined for their chemistry, mineralogy and petrography. These samples were collected from several key locations, including within drill core that penetrates an area immediately beneath ore along the Mount Whaleback fault at Mount Whaleback. Compared to unaltered black shale from Wittenoom Gorge in the north and altered black and red shale at Mount Whaleback, reddish-green shale below the Mount Whaleback deposit is significantly enriched in MgO and CaO and depleted in SiO2. Samples of this shale consist predominantly of fine- to medium-grained dolomite and ankerite cut by chlorite and carbonate veins, contrasting with unaltered equivalents that contain mostly stilpnomelane, K-feldspar and relatively minor carbonates. This alteration is distinct from assemblages developed during regional metamorphism, and possibly represents hydrothermal alteration after metamorphism. Although several questions remain unanswered, these results support models that invoke an early hypogene stage during the formation of the martite-microplaty hematite deposits in the Hamersley Province.

Jan 1, 2005

By Miguel Angel Berrocal Mallqui

La principal acción de la voladura de frentes de avance en minería subterránea es la generación de una cavidad libre, a través de taladros que conforman el esquema del corte destinado, la cual busca crear una segunda cara libre de otra sección más grande y así facilitar la rotura del resto de los taladros en dirección hacia dicha cavidad. De forma que en muchas excavaciones subterráneas se practican una serie de modelos de cortes en función al tipo de roca, dureza, porosidad, alteración y otros. En ese sentido, el presente texto describe la aplicación geomecánica del corte a través de tres taladros en la perforación y voladura en la mina Antapite de INMINSUR S.A y La Maruja de Mineros Nacionales S.A (Colombia). Dicho corte denominado alcancía consiste en la realización de un taladro central de gran diámetro (64 mm) y dos taladros de menor diámetro (38 mm) opuestos diametralmente en el mismo eje, los cuales tienen como condición ser ubicados en la dirección paralela a la tensión principal mayor presente en el macizo rocoso y la distancia de separación entre taladros de arranque depende del tipo y calidad de la roca.

Sep 12, 2005

By Luis Henrique Torres Dantas, Maycon Athayde, Rossano Augusto Pilon Nunes

The objective of this work is to evaluate the physical quality achieved in the iron ore pellets and the temperature profile in the pellet bed by applying an inversion in the flow during the cooling. The firing of pellets requires a minimum residence time in the sintering temperatures of the hematite grains [1]. The applied concept aims at raising this time to pellets located at the bottom of the bed which would provide an improvement in the physical quality of the product. The tests were carried out in a pot-grate type oven and the samples of fired pellets were divided into three aliquots according to the loading position of the pot termed top, middle and bottom, the pellets were sieved and subjected to physical tests and the compared to conventional indurating flow with the same ores and inputs. It was possible to show an increase of 7 to 8% in the compressive strength of the medium and bottom layers, maintaining the top layer results. The objectives of the research were achieved and the tests will be extended to assess the impacts on the mass and energy balance of the indurating machine and its components.

Oct 1, 2019

By M. Neven, R. A. Steane, E. Lam

"The Key Lake uranium mill is located in Northern Saskatchewan. It treats a high grade, complex uranium and metal sulphide ore. The plant and process are in many respects unique, because commercial treatment of this type of uranium ore had never been done before. The process and engineering design was based on extensive laboratory test results. A pilot plant testing stage was omitted because of confidence in the test results and time constraints to bring the plant into production.The bench scale testwork on exploration drill core samples along with preparation of the feasibility study and environmental impact statement were carried out between 1976 and 1979. The contract for detailed engineering was awarded to Wright Engineers of Vancouver in late 1980 and in August of 1981 following a public inquiry, approval to proceed with construction was granted.Construction began immediately, and during the winter the foundations for many of the plant buildings were poured and by the beginning of the following winter the buildings had been erected and installation of equipment began. Despite a six month construction worker strike in 1982, the crushing plant started up in June of 1983 and ore processing commenced in October of that year, approximately 3 months behind the original schedule.This paper describes the mill design and compares the expected performance, with the operating experience. Emphasis is directed towards flowsheet and equipment changes made since start-up, operational difficulties encountered and further improvements envisaged. Auxiliary systems are only discussed where they directly affect mill operation."

Jan 1, 1986

By Jorge Chirinos Morales

El presente trabajo describe el proceso aurífero con polvo y zinc desarrollado en la mina Algamarca a través de cuatro procedimientos: Precipitación con polvo de zinc o MEC (Merrill Crowe), carbón en Pulpa o CIP, carbón en Columna o CIC, y la lixiviación en Rumas o LIR. La finalidad de su aplicabilidad es determinar cuál es método más adecuado para la extracción del oro dentro del marco técnico-económico. En ese sentido, la evaluación se dio entre el período de 1989 y 1990, donde se operó con el proceso denominado Carbón en Lixiviación o CIL y se aplicó los métodos MEC y CIP. De acuerdo a esto, los procesos últimos se ajustan a las características propias de los minerales existentes en el yacimiento. Sin embargo, es conveniente utilizar el proceso LIR en los minerales de la veta Leona y donde no hay acceso para el transporte del mineral en camiones hasta la planta de lixiviación. Asimismo, la elección del proceso a emplear en una planta de lixiviación debe resultar de una adecuada evaluación de todos los factores que influyen en los resultados de la operación.

Apr 1, 1991

By W. M. Bangert, F. S. Boericke

"INTRODUCTION Previous investigations of the Boulder City station of the Bureau of Mines have demonstrated that low-grade domestic chromite concentrates can be roasted with carbon to obtain selective reduction of the contained iron, and that the reduced iron can be removed by acid leaching of the roasted products to produce residues with higher chromium iron ratios. Thus, some chromite ores or concentrates that originally contain too much iron to be acceptable for the production of ferrochrome can, by this treatment, be rendered marketable as ""high-grade"" chromite. 3/The present report supplements the earlier work of the Bureau and re¬cords the results of small-scale laboratory tests investigating the effects of:1. Temperature and time of the reducing roast.2. Chromite and carbon particle size.3. Ratio of carbon to chromite in the initial roast mixture.4. Variations in the alumina and silica content of the ore.5. Back-oxidation of the roast product.6. Temperature and time of leaching .of roast product.This work differs from that done previously in that particular emphasis was placed on roast mixtures containing just enough carbon for the reduction of the iron in the chromite, whereas some two and one-half times this amount of carbon was used in the earlier work.In addition to these tests, the mechanism of the production reactions was examined for the purpose of explaining the precance of acid-soluble chromium, which occurs under certain conditions of chromite reduction."

Jul 1, 1945

By D. A. Sutch

En 1958 se instalaron dos hornos Tysland-Hole en la planta Siderúrgica de Chimbote, construído por Elektrokmisk A.S, cuya sede social se encuentra en Oslo, Noruega. En ese sentido, el presente texto describe el funcionamiento de dichas hornos para la reducción de minerales de fierro en Chimbote. Para el revestimiento del horno se emplean materiales aislantes diversos y tres tipos de mezclas refractarias que se colocan mediante apisonado. Asimismo, estas mezclas retractarias son apisonadas contra moldes metálicos que permanecen "insitu", es decir, que reciben la primera carga del horno.

Sep 1, 1963

By L. K. ARMSTRING

ANYONE doubting prosperity in the mining industry should visit the Kootenays of British Columbia where the West Kootenay Power & Light Co. is kept busy running new power lines and connecting mines and mills with lines already in service. Quoting from an inspired statement "The four hydro-electric plants of the West Kootenay Power & Light Co. on Kootenay River have been in continuous operation." At the recent 35th annual meeting of the Eastern' British Columbia Boards of Trade held in Nelson, a two-day session indicated unusual activity. The following information was obtained through personal contact, through the press, and by hearsay. Much of it has been checked and proved accurate. Reversing the order of the flowsheet. Secretary J. R. Hunter reported as fol¬lows regarding the value of the 1934 production of the Consolidated Mining & . Smelting Company's metallurgical, plants at Trail and Tadanac:

Jan 1, 1935

By D. Berkley

"The competitive pressure, the increasing energy costs and the environmental regulations impose substantial challenges to the definition of power plants serving industrial facilities. Primary mining and metallurgical facilities have even greater challenges because they are often located remotely, where the fuel supply can be a problem. The absence of a power grid imposes challenges on the reliability and quality of the electrical energy supply. In addition, the facilities usually require thermal energy too, not only electricity.This paper outlines these types of issues that have to be considered when defining a cogeneration plant integrated with a remotely located industrial facility. It is addressed to the “users” of cogeneration facilities rather than to “generators.” The focus is on analyzing various site-specific design considerations to prescreen the feasible cogeneration alternatives and minimize the number of options to be analyzed from the economics viewpoint. This approach could substantially reduce the engineering effort and schedule during the feasibility phase of the project.The front-end of the paper provides a basic understanding of cogeneration plants of various types to establish a common language. Subsequently, the paper outlines and analyzes specific issues that could be of help in the definition of cogeneration installations for remotely located industrial facilities, with a focus on mining and primary metallurgical plants"

Jan 1, 2003

By F. A. Rutledge, B. S. Webber, J. M. Moss

"INTRODUCTION The United States, with its vast resources of relatively low-grade zinc been the world's leading producer of zinc -metal for many years. The expanded zinc production during the period, 1939-44, inclusive, was induced by favorable premium prices and has depleted the known ore reserves in the United States. The 1943-44 rate of zinc production cannot long be maintained in the United States, especially if premium prices are removed. Domestic zinc reserves, have been depleted to such an extent that it is doubtful if our mines will again be able to completely and continually fulfill the needs of this country.The Bureau of Mines, anticipating a postwar consumer demand for 550,000 to 750,000 tons of slab zinc and an additional 100,000 tons for use in paints and chemicals, sent two engineers to Sedanka Island in July 1945 to investi¬gate the deposits near Biorka Harbor.ACKNOWLEDGMENTIn its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion the Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches are under the supervision of Dr. R. S. Dean, assistant director."

Nov 1, 1946

By Sandeep Kumar Jeripotula, Govinda Raj Mandela, Aruna Manglapady

Dozer operators are frequently exposed to whole-body vibration (WBV) during the execution of their work. Occupational exposure to WBV in Indian surface coal mines was evaluated by measuring vibration intensity and duration of exposure. A triaxial accelerometer was placed on the operator seat surface for taking the readings. Based on frequency-weighted root mean square acceleration equivalent to 8-hr shift duration, i.e., (A(8)) all dozer operators have exceeded an Exposure Action Value (EAV) of 0.5 m/s2 , and 90% of dozers did not exceed Exposure Limit Value (ELV) of 1.15 m/s2 . Based on Vibration Dose Value (VDV (8)), all dozer operators have exceeded Exposure Limit Value (EAV) of 9.1 m/s1.75, but no dozer operators have exceeded Exposure Limit Value (ELV) of 21 m/s1.75. Further, an epidemiological study was performed for identifying the extent of musculoskeletal disorders (MSDs) among dozer operators. For the detailed study, 42 dozer operators and 22 controls were selected from 2 surface coal mines. The control group was not exposed to WBV. It was seen from the cross-sectional study that pain in the lower back was predominantly higher (83.33%) in the exposed group when compared with the control group (31.81%). Likewise, pain in the neck (47.61%), shoulder (42.85%), knees (42.85%), and ankle (11.90%) was higher in the exposed group than that of the control group (22.71%, 0%, 45.45%, and 4.54%). A significant observation among the exposed group was that there was degradation in the quality of life. The outcome of the study would assist in monitoring and mitigation of machinery-induced vibration diseases (MIVD) in India and generally applicable to most of the mechanized mines as well. However, comprehensive studies are still needed to enunciate the magnitude extent.

By P. F. Ziemkiewicz

This project evaluated the performance of nine passive treatment methods by studying 137 treatment units in eight eastern states. Performance was normalized according to construction cost, projected service life and tons of acid load treated. Results were dimensioned as $/tons of acid load treated/year. These costs were then compared to those of chemical treatment. Sites that achieved acid load reductions at costs below those of chemical treatment were considered successful. In addition to evaluating the performance of the treatment methods, this paper describes the various passive treatment systems, their applications and performance data for individual treatment units.

Jan 1, 2003

By Stephen P. E. Redmond

A 15 km water supply tunnel is being constructed in Buenos Aires, Argentinata expand the capacity of the existing system. Two 4.3 meter diameter Earth Pressure Balance (EPB) tunneling machines operating at times from the same shaft on a congested work site and advancing through sedimentary deposits underlying this wonderful city pose interesting challenges. As of January 1999approximately 50% of the tunnel has been excavated. Combined machine production rates of 1026 m/month have been achieved. Presentations made in prior proceedings can be referenced for details of the overall Project scope and for details of the tendering process. The purpose of this paper is to compliment those presentations by addressing now the execution of the work.

Jan 1, 1999

In 1992, the United States economy grew at a rate of 2%. The Gross Domestic Product rose to $5,946 billion. With 257 million people - 635,000 in mining including petroleum - the United States has more than 100 million dwelling units and more than 190 million licensed motor vehicles. New private housing starts rose I 1 % to 1.2 million units. New car production rose 4% to 5.7 million units. Truck and bus production rose 20% to 4 million units. The rate of inflation was 3.5% and the prime rate of interest was 6.25%. The Producer Price Index (1982 =100) was relatively unchanged from 1991 as follows: fuels and related products and power 80, metals and metal products 119, chemicals and allied products 126 and nonmetallic mineral products 117. Energy Imports of crude and refined petroleum, costing $50 billion, rose 3% to 455 Mm3 (2.9 billion bbl). Domestic petroleum production fell 1 % to 582 Mm3 (3.5 billion bbl). Petroleum supplied about 41 % of US energy, natural gas 24% and coal 23%. Coal production, 60% from surface operations, rose 1 % to 914 Mt (1 billion st). About 78% was used to generate electricity and 3% was coked. Exports valued at $4 billion included 57 Mt (63 million st) of metallurgical coal and 39 Mt (43 million st) of steam coal. Ura¬nium mining, including recovery from phosphates, fell 18% to 3 kt (3300 st) U308.

Jan 1, 1993

By H. Wotruba, L. von Ketelhodt, M. Kowalcyk, C. Kleine, M. Robben

Sensor-based sorting is a financially and technically viable technique that is operating with little or no water and relatively little power consumption. Sensor-based sorting has already proven its operational stability at two gold applications in South Africa. Sensor-based sorting cannot only turn waste dumps and diluted mining blocks into reserves. The implementation can also cause a decrease in specific operating costs of mill and mine when for example replacing selective mining by bulk mining methods with subsequent sorting. Successful installations, operational experience, test work data and flow sheet integration from mine-to-mill underline the impact and potential that sensor-based sorting can have on the gold mining and processing industry.

Jan 1, 2011