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This Bureau of Mines publication contains the texts of the four papers presented at the May 6-7, 1980, seminar on the role of overburden analysis in surface mining. Coverage includes the geologic distribution of pyrite and calcareous material and its relationship to overburden sampling, overburden sampling and analysis, use of soil-overburden data in mine planning and development, and minesoil classification.

Jan 1, 1981

By Mandeep Singh

The smelting of lead ores has been carried out in southeast Missouri for centuries, and modern smelting practices have generated a variety of waste products. Lead blast furnace slag is one such product, which typically contains 10% zinc, 25% iron and 2% lead. This slag has often been stockpiled on the producing smelter site and accumulations have now reached several million tonnes. It is possible that in the near future these slags will be classified by the federal Environmental Protection Agency as hazardous, and therefore there is considerable interest in possible treatment processes to render the slags non-hazardous by removing the offending metallic elements. To ensure that the overall slag processing costs are kept to a minimum, it is imperative that lead and zinc be recovered in a form suitable for sale or further processing. There are two generic routes for processing blast furnace slags and they involve hydro-metallurgical or pyrometallurgical techniques. With hydrometallurgy, the slags would be leached directly and the metal values recovered from purified leach solution(s) by electrowinning. One problem with processes of this type is that the zinc and lead grades of the slags are low and the iron content is high, and thus the economics of metal production are often not favorable. For pyrometallurgical processing (1), it has been shown that the slags can be fumed to produce an oxide dust containing all the lead and zinc, and representing only a fraction of the weight of the initial slag. The oxide dust may then be processed hydrometallurgical to recover zinc and lead.

Jan 1, 1992

By AIME AIME

ON THE occasion of the eightieth birthday of Captain Robert W. Hunt, the Iron and Steel Committee of the Institute, desiring to commemorate the great contributions made to the steel industry by Captain Hunt during his long career, conceived the idea of a Hunt Medal to be awarded annually by the Institute for meritorious contributions to the art of making steel. The project was received enthusiastically by all to whom it was proposed, especially by Captain Hunt's partners and employees who considered it their right, and asked for the privilege of -. - raising the necessary funds within their own circle. This was agreed to, and the Institute has received from them $7500 as an endowment fund to provide an annual award, and $1000 for the expenses of providing of medal.

Jan 1, 1920

By Brett Schug, Caelen Anderson, Sohail Nazari, Carlos Cristoffanini

"The Haile gold mine in South Carolina is increasing the automation level of its processing plant in order to improve operational stability. One step toward this goal is the application of a digital twin concept to provide virtual instruments. Haile has engaged Andritz to implement virtual instruments at its grinding area hydrocyclones and at its tailing thickener underflow pump. These virtual instruments provide density values in a traditionally difficult location for reliable slurry density measurement. The digital twin is a first-principles integrated design engineering with advanced simulation (IDEAS) simulation model, connected in real time to the control system. Results have been promising, with the virtual instrument values matching the physical instrument under normal operating conditions and showing better prediction under upset conditions. Haile plans to use the virtual instruments as optional process control parameters.OceanaGold’s Haile gold mine is located near Kershaw, SC, about 80 km (50 miles) southeast of Charlotte, NC. This location was first mined in 1827 and has produced gold through several operating periods since then, including a heap leaching operation from 1985 through 1992. In October 2015, OceanaGold acquired Romarco Minerals, the previous owner of the Haile operation.The current operation began in 2017 as an openpit mine with additional underground resources. The nameplate throughput is 5,760 t/d (6,350 stpd) ore, and 2017 production was 3,345 kg (118,000 oz) gold, with 3,968 to 4,384 kg (140,000 to 155,000 oz) gold expected in 2018. Proven and probable reserves exceed 85 t (3 million oz) gold at a grade of 2 g/t (0.06 oz/st) gold. The process, as shown in Fig. 1, includes a primary jaw crusher, comminution with a semiautogonous grinding (SAG) mill and ball mill circuit, flash flotation, rougher flotation, regrinding, pre-aeration, carbon-inleach leaching, carbon elution and regeneration, cyanide recovery, electrowinning and refining. The Haile operation’s inaugural gold pour took place Jan. 20, 2017. Mine life is expected through the year 2030."

Dec 1, 2018

By Greg Wyartt

In the Pilbara region of Western Australia, an iron ore mine is undertaking a high wall cut-back to improve stability and allow access to deeper ore deposits. Several sections of the wall have been classified geologically sensitive due to unstable localised geology, and therefore an engineered approach to vibration critical blasting was required. The use of electronic detonators allowed multiple signature (seed) holes to be incorporated into a production blast adjacent to the geologically sensitive area, therefore providing baseline vibration data to be used for future modelling with the added advantage of eliminating unnecessary pit closure downtime typically associated with a signature hole program. All subsequent blast patterns also incorporated multiple signature holes to provide additional data and allow continual updating – and therefore improved accuracy - of the blast prediction model.

Jan 1, 2018

Palabora Mining Company (PMC) processes a multi-component ore body using a circuit consisting of two AG mills in parallel, closed with vibrating double deck screens and hydrocyclones. The bottom screen undersize feeds the hydrocyclones, but the screen oversize products can be treated in a variety of ways. The top deck screen pebbles can be crushed and then combined with the bottom deck oversize and recycled to the AG mill. Alternatively both the top and bottom deck screen oversize can by-pass the recycle crusher and be recycled directly to the mill. A full tap-off is a configuration when both the top and bottom deck screen oversize streams are stockpiled. The other configuration is when the bottom deck screen oversize is recycled to the mill while the top deck screen oversize is stockpiled - termed partial tap-off. This article reports the findings from the surveys performed to evaluate the performance of the PMC auto mill circuit when operated under the four different configurations discussed. Ore characterisation tests were performed to assess the deportment of the key ore components for the different configuration.

Jan 1, 2012

By P. W. Conrad, C. Todd, N. A. Degerstrom, N. West, R. Kramer

"Surface subsidence caused by underground room-and-pillar mining operations and by solution mining operations have been studied separately but never in combination. In 2008, FMC Minerals began using solution mining at its Westvaco Mine as a secondary extraction method in an area that had been previously mined using the room-and-pillar mining method. Mining regulations require that subsidence associated with underground mining activities be monitored and measured annually. Using Salt_Subsid, a subsidence software package from the Solution Mining Research Institute, and ArcGIS, Esri's mapping platform, researchers at Montana Tech were able to develop a relationship between measured surface mine subsidence and solution mining that can be used at the Westvaco Mine to estimate the production of trona from solution mining operations. Project backgroundFMC Minerals has increased the production of trona from its Westvaco Mine near Green River, WY, using solution mining as a secondary extraction method in an area previously mined using the room-and-pillar method. The area of interest was mined until 2001 with the use of a borer miner at a depth of approximately 488 m (1,600 ft). Currently, FMC determines the amount of trona produced using its solution mining operations by measuring the dissolved solids pumped from the mine. This approach, however, does not account for the location from which the trona was removed.The location from which the trona is removed and the size of the cavern created by the solution mining operations are important to FMC’s mine planning. FMC believed that with proper investigation of the subsidence at the Westvaco test site, a correlation might be found between surface subsidence measurements and the amount and location of trona production from the solution mining activities. The primary goal of this project, conducted by Montana Tech, was to find relationships between the measured subsidence and the solution mining activities. The project attempted to develop an equation that could be used to predict solution trona production based on measured subsidence. The project attempted to model the relationship between the measured surface subsidence and solution mining production using Salt_Subsid, an existing subsidence software package from the Solution Mining Research Institute (SMRI, Clarks Summit, PA) to estimate the location, size and shape of the solution mining cavern. This study would determine the program’s usefulness for locating and developing the cavern created by secondary solution mining activities. The subsidence and production data sets used in this study were collected over a seven-year period from 2008 through 2014."

Jan 4, 2018

By T. W. Beck

Drilling into coal mine roof strata to install roof bolts has the potential to release substantial quantities of respirable dust. Due to the proximity of drill holes to the breathing zone of roof bolting personnel, dust escaping the holes and avoiding capture by the dust collection system pose a potential respiratory health risk. Controls are available to complement the typical dry vacuum collection system and minimize harmful exposures during the initial phase of drilling. This paper examines the use of a bit sleeve in combination with a dusthog- type bit to improve dust extraction during the critical initial phase of drilling. A twistedbody drill bit is also evaluated to determine the quantity of dust liberated in comparison with the dust-hog-type bit. Based on the results of our laboratory tests, the bit sleeve may reduce dust emissions by one-half during the initial phase of drilling before the drill bit is fully enclosed by the drill hole. Because collaring is responsible for the largest dust liberations, overall dust emission can also be substantially reduced. The use of a twistedbody bit has minimal improvement on dust capture compared with the commonly used dust-hog-type bit.

Jan 1, 2014

By C. Kathryn Sole

The close proximity of cobalt and nickel on the Periodic Table and their frequent occurrence together in nature means that their separation in primary hydrometallurgical flowsheets is not only often necessary, but requires the use of innovative chemistry to achieve high selectivity. Today, increasingly stringent demands for the high-purity cobalt and nickel salts required for battery applications in consumer electronics, electric vehicles, and solar applications are again challenging the state of the art. The evolution of cobalt–nickel separations is traced from the basic precipitation technologies employed in 1960s, through commissioning of the first cobalt solvent-extraction plant in South Africa in 1974, to the commercialisation of organophosphinic-acid extractants (which provided a step-change improvement in selectivity) and their eventual widespread use in the 1980s and ’90s. This was followed later by their sulphur analogue, which enabled different possibilities for laterite processing in the new millennium. Separations in chloride media, which take advantage of the different speciation chemistries, and nickel extraction by oximes in ammoniacal systems are also discussed. More recently, chelating and solvent-impregnated resins have added further dimensions to the possibilities for flowsheet design and enabled higher purity products to be attained from both primary and secondary sources. Selected case studies and flowsheets are described.

By Emery R. Hayhurst

SILICOSIS has been described in a report of the American Public Health Association as a disease due to breathing air containing silica, characterized anatomically by generalized fibrotic changes and the development of miliary nodulations in both lungs, and clinically by shortness of breath, decreased chest expansion, lessened capacity for work, absence of fever, increased susceptibility to tuberculosis (some or all of which symptoms may be present), and by characteristic X-ray findings. ... The disease is divided arbitrarily into first, second, and third stages for convenience of description and possible compensation purposes. At least two distinct types of silicosis are recognized, acute and chronic. The acute form was reported as early as 1713, when a British patent for grinding flint by wet methods was granted because the dry powdered material "proved very destructive to mankind, so much that any person, ever so healthful, working in that business cannot possibly survive over two years."

Jan 1, 1936

The Mine Safety and Health Administration (MSHA) defines an independent contractor as "any person, partnership, corporation, subsidiary of a corporation, firm, association or other organization that contracts to perform services or construction at a mine." Contractors that perform specific types of work are required to report the number of employees who perform work at coal mines and at noncoal mines.

Jan 1, 2004

1. In 2002, a total of 2,820 contracting companies reported employment at coal mines to MSHA.

Jan 1, 2004

By H. Pearce, A. E. Lewis, A. Ochieng

Hydrodynamics and mixing are fundamental to the operation of mineral process systems such as flotation cells and metal precipitation reactors. The computational fluid dynamics (CFD) technique has been employed in the present work to study the hydrodynamics in a mixing vessel stirred with either a Rushton turbine or a pitched blade impeller. The multiple frame of reference (MFR) approach has been used to model both impellers. A draft tube was used only in the Rushton turbine stirred vessel. The flow profiles for the pitched blade impeller have been studied in three regions; below the impeller tip, at the middle of the tank, and near the liquid surface. The simulation results were compared with literature data obtained using a laser Doppler velocimetry in the three regions of the vessel, and it was found that the model predictions were better in the impeller region. There was a poor prediction of the experimental results in the region closer to the liquid surface; however, this was improved when the turbulence parameter (C2) in the k-e model was set to a higher value. The value of the impeller clearance at which the Rushton turbine generates an axial impeller type flow has been determined and it has been shown that, at this clearance, a draft tube can be used to enhance axial flow in a Rushton turbine stirred reactor.

Jan 1, 2003

By Brad Bulow

Blasting is an essentially violent process aimed to disrupt and loosen rock for productive excavation. Some dilution of any ore present is the inevitable result. This makes blasting a dirty word to most geologists, particularly in narrow vein gold mines. A 1% increase in gold recovery may be worth $1 M extra revenue to a large mine.

Jan 1, 2000

By C. Roos

Tradicionalmente en la industria minera, el flujo principal del proceso funcional para la evaluación de recursos y reservas procede de geólogos que elaboran el modelo geológico, de allí a los geólogos que hacen la estimación de los recursos (los modeladores) quienes estiman los grados, y a los ingenieros de mina que desarrollan el diseño de la mina y su calendario. La interfaz entre estas tres disciplinas no está siempre exenta de baches. Las presunciones hechas durante una etapa del proceso no siempre son comunicadas a los demás, a pesar que la mayoría de las empresas mineras tienen procedimientos y protocolos establecidos para promover la comunicación a lo largo de las distintas disciplinas. Estos procedimientos no siempre logran su propósito debido a una variedad de razones que incluyen restricciones de tiempo, no tener disponible a las personas apropiadas, o a una falta de entendimiento de lo que las otras disciplinas requieren, y el proceso de traspaso puede degenerar en el envío de archivos a la siguiente disciplina en el flujo de proceso. Este artículo se ocupa de la interfaz entre la estimación del recurso y las disciplinas de la ingeniería de minas y el esquema de algunas de las presunciones comunes hechas al generar un modelo del recurso y los riesgos que los ingenieros podrían correr al elevar los grados de corte, optimizar calendarios o realizar predicciones. Los casos de estudio presentados se centran en depósitos de oro a cielo abierto, pero los conceptos deben ser aplicables a toda la industria. Aquí también proveemos un resumen de preguntas clave y recomendaciones.

Jan 1, 2014

By Victor V. Nazimko

Long term stability of the pillars that have been remained after R&P extraction causes postponed subsidence. To prevent unforeseen subsidence and to diminish postponed subsidence 25-50% new method for its control has been developed by the author. It supposes to use drilling and blasting technology and other original approaches. New method has been fulfilled through the holes being drilled from the surface or from the active underground openings. Explosives had been charged into the holes and were blasted. This had increased bulking factor dramatically and prevented natural caving of the strata. Physical scale modeling corroborated efficiency of the new approach. The bulking factor has grown from 0.0623 to 0.1185 and surface subsidence has been diminished from 1.1 m to 0.2 m or 5.5 times.

Jan 1, 1996

By Paul Hatmaker

Lime was a highly useful commodity thousands of years before the simple chemistry of its manufacturing process was known. The employment of lime for agriculture, building, and even certain essentially chemical purposes is so old that its origin is among the unrecorded details of man's first ventures into the manufacture and use of prepared substances. Lime is a most versatile material and consequently has come to be widely utilized in modern civilization. Immediately before the depression of the early 1930's the annual production of lime in the United States was more than 4 million tons, valued at 33 to 42 million dollars. This output was sold to many industries, so many that mere enumeration becomes tedious. In addition to agricultural and building lime the sales statistics compiled annually by the Bureau of Mines include lime sold to the steel and other metallurgical industries as refractory and fluxing material, as well as that used by paper mills, glass works, tanneries, and water-treatment plants. These major uses normally consume about 86 percent of the domestic sales. The remaining 14 percent includes lime sold for use in the manufacture of alcohol, alkalies, bleaches, calcium acetate, calcium carbide, coke gas and byproducts, glue, insecticides, oils and fats, paints, and rubber, in the refining of salt, in the manufacture of sand-lime and slag brick, in the disposal of sewage and garbage, in the manufacture of silica brick, in the refining of sugar, in the textile industries, and in wood distillation. Many other uses are also known for which complete sales data are not available.

Jan 1, 1934

By Ioannis K. Kapageridis

The lignite deposits of the Kozani-Ptolemais-Amyntaio basin in western Macedonia (North-West Greece) present a difficult modelling problem. Each deposit consists of several thin lignite layers ranging from a few centimetres to a few tens of centimeters in thickness, and thin intercalated sterile layers of marly limestones, marls, clays, and sands. These layers are practically impossible to model individually due to fast lateral transition of lignite layers to humus clay and vice versa and the lack of reliable and detailed stratigraphic correlation, leading to compositing methods being applied prior to any interpolation and modelling. The complexity of the deposit is further increased by the presence of a number of faults. This paper presents the modelling and estimation procedures applied during the most recent study of the South Western Field ? a new deposit that is considered for development and lignite production over the next years and will support the operation of a new power station in the area. Special focus is given to drillhole database structuring, fault modelling, stratigraphic correlation, mineable lignite intervals compositing, and resource estimation. The use of specialised mine planning software in all stages of modelling and estimation is thoroughly explained.

Oct 1, 2009

By Harold Vance

The Lafitte field, the largest oil reserve in South Louisiana, is in Jefferson Parish, some 25 miles due south of the City of New Orleans. The discovery well, The Texas Company's No. I, Louisiana Land and Exploration Co., in the southeast corner of sec. 19, T. 17 S., R. 24 E., was completed on May 15, 1935. The initial production of this well was 960 bbl. of 34.9º A.P.I, gravity oil per day, through 1/4-in. choke, with a tubing pressure of 1600 lb. per sq. in. Producing depth was 9558 to 9572 ft., the total depth being 9572 feet. The development of the field has been at the rate of three to eight new producing wells per year. Up to Jan. I, 1944, 60 producing wells and three dry holes had been drilled, while two of the original producing wells had been abandoned, Although the field is not unitized, The Texas Company was the sole operator in the field until the Lafitte Oil Co. completed its NO. I Jefferson Parish, near the center of the west line of the NW/4 sec. 20, T. I7 S., R. 24 E., on July 27, 1941. No additional wells have been drilled by the Lafitte Oil Company. Drilling and WeLl-completion Practices All drilling operations have been conducted with the steam-driven rotary equipment mounted on submersible barges. A canal is dug to the well location and the drilling unit is floated into position. The seacocks are then opened and the barge settles to the bottom. After the well is completed, seacocks are closed and water is pumped out of the barge. This procedure permits the barge, with drilling equipment still in place, to be floated and moved off the location. The conventional open-hole and the gun-perforation method of completing wells has been used in this field. Where possible, the initial completion is from the deepest 'sand and recompletions are made progressively up the hole, by plugging back with cement to the upper sand and gun-perforating opposite the new sand. The oil string usually is 7 5/8 in., 26 to 34-lb. casing. Three wells have been completed using 9 5/8-in. 44-lb casing set below 10.000 feet. Fig. I shows the completion and recom-pletion practices on one well in the field. This figure also shows the relative locations of the different producing sands as shown on the electric well log. Structure The structure is an elongated dome, cut by two north-south faults, which divides the field into three segments. The west segment is the highest structurally and contains most of the recoverable oil and gas. The center segment is less important and the east segment is of little value. Figs. 2, 4, 6, 8 and 10 are depth contour maps on top of the five main producing sands in the field. These maps show the relative size of the five reservoirs and the

Jan 1, 1945

By J. D. Forrester

In striving to develop this discussion about "Manpower for Industrial Mineral Industries" two fundamental classes of manpower are encountered. These are: 1) The Labor Force, comprised of unskilled and semi-skilled, nonprofessional personnel who participate in conducting economic, mineral deposit operations and; 2) The Professional People involved in the science, engineering, and management of such industrial enterprises. The commentary given here will be directed primarily to a review of the characteristics of the second or latter class. To pursue successfully a career as a scientist or engineer in today's industrial and social complex, it is necessary that technical knowledge must have been acquired by training and study in an institution of higher learning. Also, to act effectively, the individual must have achieved some degree of specialzation, although this element often is developed to most notable degree by post-graduate exposure and experience. In addition, and especially in the case of "management," it is desirable, indeed it is even necessary, that an individual recognize and appreciate the fundamental humanistic-sociological controls, and their nuances, as these elements exist to shape his total environment.

Jan 1, 1969