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By Joseph J. Wojcik

INTRODUCTION A great deal more is involved in a sampling effort directed at a placer deposit than physically capturing a quantity of representative material and extracting the desired component. The distribution and dimensions of the sample sites must be chosen after consideration has been given to the type of deposit and the concentrating mechanism. Interpretation of the sampling results is likewise an extremely important part of the sampling program. SAMPLE SPACING The interpretation begins with the selection and design of the sampling program. A decision regarding genesis of the deposits and their geometry must be made in order to select a suitable technique and sampling pattern. Deposits differing genetically will have differing distributions and degrees of concentration.

Jan 1, 1992

By R. F. Merwin

Advancement in automation intensifies the need to remove tramp iron from bulk materials being processed and carried on belt conveyors. Although magnets have long been employed for this purpose, it becomes increasingly necessary that magnetic equipment of appropriate types and sizes be selected and advantageously installed -- if maximum benefits are to be derived Tramp iron present in bulk materials consists of ferrous trash, such as wire, bolts, nails, equipment parts, tools, and machine cuttings. The results, if the iron is not removed, are damaging to equipment having close clearances, explosions, or fire, En the case of flammable materials, production downtime losses, and contaminated products.

Jan 1, 1966

By Jay Jones, William D. Rech

The Henderson Mine developed a water treatment system in 1985 to meet the NPDES requirements for its mine water discharge. Unacceptable levels of Zinc and Manganese formed the basis for the design and operation of the treatment system. Since initial start up, this system has reliably removed metals from the mine water and facilitated low cost compliance with water standards. The potential addition of a bio- monitoring requirement to the NPDES Permit in 1990 has added a second dimension to the metals removal process. This paper will review the history of Henderson's success at developing a low capital treatment system for metals removal and the anticipated effects of bio-monitoring upon this system based upon preliminary bio-monitoring screening.

Jan 1, 1991

By Jed H. Mosgrove

One of the most interesting of all the subjects required of persons studying the different facets of coal mining is coal mine gases. Some mine gases have been a real problem since the very beginning of underground mining, and in the early days there was insufficient knowledge to cope with them. The history of mining shows that until about the last 50 years, much work was done primarily by the hand methods which are primitive by today's standards. Miners had to contend with gases without the aid of enclosed lighting, permissible mine machinery, sophisticated testing devices, and high-pressure ventilating fans. In early days the miners were not educated about the different mine gases nor did they have the technical equipment to determine the actual composition of the deadly atmospheres they encountered. They simply applied a descriptive term to each gas or mixture of gases depending on its effect on a person or the surrounding atmosphere. The gases or mixtures of gases were then referred to as "damps," a term which was probably derived from the German word "dampf," meaning vapors or gases. The more common damps encountered were : Blackdamp A condition of the atmosphere in which a miner's light would be extinguished and in which breathing would be difficult, sometimes even resulting in suffocation. An atmosphere deficient in oxygen which could contain a combination of any of the mine gases Firedamp A flammable mixture of methane and air which would either burn or explode when ignited. White Damp A mixture of gases containing carbon monoxide, most often found in mines during fires or after explosions.

Jan 1, 1981

By C. Anastasiadis

The wettability of sandstone was investigated using the technique of dielectric spectroscopy in the frequency interval 1kHz-1MHz. The natural wetness of the material was modified to get two different sets of samples, one with sea-water wetness and the other with crude oil wetness. Measurements showed that the electric responses of water-wet and crude oil-wet samples were markedly different beside the fact that the dielectric response of both groups of samples obeys a general fractional power law. The dispersivity, of the complex permittivity component that expresses the material loss with respect to the electric field was found to be the most suitable parameter to check the wettability of the samples.

Jan 1, 2005

By Mathew B. Revell, Martyn L. Bloss

The paste fill system at BHP Cannington's underground silver-lead-zinc mine is described. The paste fill system has been operational since December 1997 and is the first of its type in Australia. Technical and operational learnings since stope filling commenced are presented. Topics described include plant performance, reticulation system design and construction, pipe wear and failure, rheology, in situ performance and laboratory testing.

Jan 1, 2001

By N. Magdalinovic

This paper analyzes the basic elements important for sustainable development in the sphere of metal mineral raw materials and offers one of the possible ways of defining the index of sustainable development.

Jan 1, 2007

By Byron M. Jones

The use of computers in system analysis is well established. Analog computers have been used for this purpose since about 1940. As the power of digital computers increased and their cost decreased, much of the analysis formerly done by analog computers has been diverted to digital computers. The mathematical foundation for system analysis was laid between the years 1700 and 1900. In the 1930?s, telephone repeater amplifiers were designed using systems analysis techniques. From 1940 to 1960 systems were analyzed using either direct simulation or LaPlace transforms. Since 1960 analytical methods have been expanded to include linear vector space theory. All of these methods are being used to analyze the dynamic behavior of mining machinery.

Jan 1, 1974

By R. Cooper, K. De Wet, A. Janwong

"Horsehead Metal Products is a zinc refinery in Mooresboro, NC, treating crude Waelz oxide (WOX) to produce special high-grade zinc by a hydrometallurgical process comprising leaching, zinc solvent extraction/electrowinning, melting and casting and bleed treatment. Cadmium removal by zinc-dust cementation plays an essential role in the bleed treatment circuit to prevent cadmium buildup in the circuit. Silica, though present at a low level of approximately 0.3 percent in the WOX feed material, had a significant impact on the efficiency of cadmium cementation with zinc dust, most likely due to the passivation of zinc dust particles with silica gel. Solid/liquid separation efficiency by filter press was also affected. To identify the source of the silica issues, silica levels were mapped throughout the circuit, and adjustments, including using pregnant leach solution as the feed to cementation, and pH control in the WOX leaching and neutralization were introduced to mitigate the issues created by silica gel in the circuit. IntroductionLocated in Mooresboro, NC, Horsehead Metal Products Inc. is a hydrometallurgical zinc refinery processing Waelz oxide (WOX) to produce special high-grade (SHG) zinc. The flowsheet, known as the Modified Zincex process, consists of leaching, solvent extraction (SX), electrowinning (EW), melting and casting and bleed treatment (Fig. 1). Cadmium cementation, part of the bleed treatment process, provides an essential bleed of cadmium from the circuit, as metallic cement. The cadmium cementation circuit consists of agitated cementation reactors, a zinc dust addition system, filter presses, agitated purification (releach) reactors and a cadmium concentrate filter press.At the refinery, WOX pulp is leached at a controlled pH to achieve the maximum zinc extraction, according to the main reaction:"

Jan 1, 2016

By M. Liu

The use of surfactants shows great potential for the removal of hydrophobic organics from soils by in-situ washing techniques. Lab-scale soil washing experiments were performed using sodium dodecylsulfate (SDS), an anionic surfactant, and anthracene, a highly hydrophobic compound. The results of this research show that the solubility of anthracene increases linearly with an increase in SDS concentration above the critical micellar concentration. Furthermore, SDS can be effective in removing anthracene from contaminated sand.

Jan 1, 1993

By Jennifer B. Leinart, Otto L. Schumacher

JIM ARNOLD: Our next speaker is Otto Schumacher. He's president of Western Mining Engineering in Spokane, Washington. His company offers services in the area of mining feasibility analysis and publishes Mining Cost Service. Otto's talk will be "Are Metallurgists Overpaid?" [laughter] I know one that's not. [laughter] OTTO SCHUMACHER: I really think it's kind of a dirty trick for Doug to put me up here and pose that question since I'm a mining engineer. However, it's probably most appropriate that a mining engineer address the question because I can be more objective than the rest of you. [laughter] SPEAKER. Otto, do you promise to say something nice about metallurgists? [laughter] OTTO SCHUMACHER: I'll see how much time I have. [laughter]

Jan 1, 1998

By Colin M. Kelly

The Loveridge Mine, located near Fairmont, West Virginia, has been mining coal from the Pittsburgh Seam since 1958. As the mine develops its reserves it finds itself with increasingly distant hauls from the operating faces to the preparation plant. Initially, the mine was designed with track haulage. The coal was hauled to an underground rotary dump which fed a slope belt, to the preparation plant. As the haulage distances increased, production delays due to the track system's limitations became severe. To resolve this situation, a complete review of the haulage system was undertaken. Simulations of the present system along with future scenarios were conducted to help management effectively plan the haulage requirements of the mine for the remainder of its life.

Jan 1, 1986

By David Jenkins

Grefco Inc. operates two diatomite mines in the western Santa Ynez Mountains. The larger of the two mines, the Palos Colorados Mine, is located approximately seven miles southeast of Lompoc. The Miguelito Mine is located about two miles south of Lompoc on the west side of the Miguelito Canyon. Diatomite from the Palos Colorados and Miguelito mines is trucked to the Grefco plant at Lompoc for processing (Figure 1). HISTORY Grefco, Inc. evolved from the originating Dicalite Company which in 1929 began operations at the Walteria plant in the Palos Verdes Hills south of Los Angeles. In 1942 Dicalite leased the Palos Colorados mine at Lompoc. In 1944 the Dicalite Company was purchased by Great Lakes Carbon Corporation.

Jan 1, 1995

By Y. Topkaya, R. E. Johnson, B. R. Palmer, R. B. Bhappu, Ronald J. Roman

The hydrodynamics of the leaching solution in leach heaps is known to be one of the important variables in the performance of the heap. The solution hydrodynamics are also important in the decommissioning of a heap where the aim is to flush out the residual dissolved metals and the remaining reagents. Chemical engineers have studied the hydrodynamics of "trickle bed" reactors for 40 years in an attempt to relate the performance of trickle bed reactors to flow conditions. Their work is reviewed with emphases on areas of similarity to heap leaching.

Jan 1, 1993

By M. S. Klima, B. K. Kim

The use of a 25.4-mm- (1-in.-) diam water-only hydro-cyclone for separating liberated 125 x 25- µm high-density particles from similar-size lower-density (2.65 g/cc quartz particles, as might be used in soil washing applications, was investigated. As expected, cyclone performance was greatly affected by changes in cyclone geometry and operating conditions. A single-stage separation recovered 75% of the magnetite (4.8 g/cc) while rejecting nearly 60% of the quartz. With ferrosilicon (7.0 g/cc) as the heavy component, the recovery improved to 85%. The use of dense medium in a single stage increased both ferrosilicon recovery and quartz rejection to approximately 90% each. In addition, computer simulations of a three-stage circuit were performed. The simulations showed that recoveries approaching 97% with quartz rejections of 95% were possible.

Jan 1, 1999

By J. Hong, K. Han, C. Park, C. Yoon, H. Yoon, N. Kim

The contents of three platinum group metals (PGM-platinum, palladium and rhodium), from the spent automotive catalyst, and two NIST SRM (National Institute of Standard and Technology Standard Reference Material, Used Auto Catalysts) were determined by the X-ray fluorescence (XRF) spectrometry. The XRF technique has been proven to be a fast, effective and accurate method in determining not only PGM but also other solid materials of less soluble for wet digestion analysis. The detection limit of the XRF analysis is better than that of the inductively coupled plasma mass spectrometry which usually requires significant dilution to avoid high dissolved solid concentration. However, the XRF technique suffers from a strong matrix dependent problem. The objective of this study was to examine the applicability of the XRF analysis where the sample matrix was not exactly the same as the standard materials with particular reference to PGM analysis. This study enabled to compare the effect of various matrices including alumina, iron, copper and nickel on determination of the contents of PGM.

Jan 1, 2004

By D. T. Maiers, P. L. Wichlacz, P. A. Pryfogle, J. H. Wolfram

The effects of metal solution concentration, biomass density, length of exposure time, and pH were determined for biosorption of molybdenum (Mo) and chromium (Cr) by three organisms. Results indicate that it is possible to sorb Mo and Cr from dilute solutions. Differences were observed in the abilities of an organism to sorb Mo and Cr as well as among respective abilities of the three microorganisms. This suggests an inherent selectivity of the organism which may afford the means to control a sorption-based process. Results also indicate that the metal sorption abilities of these microorganisms depend on duration of exposure, biomass density, solution pH, and the metal concentration of the solution. Each of these parameters suggests an additional means of controlling the sorption process.

Jan 1, 1989

By Eugie Kabwe

The velocity of detonation (VOD) is a significant property considered when rating an explosive. It may be quantified as a confined or unconfined velocity. The confined velocity is the rate at which the detonation wave propagates through an explosive within a blast hole or any restrained space. The unconfined velocity emanates when an explosive is detonated in the open. However, the confined velocity is more significant as explosives are usually employed under a definite degree of confinement. This paper evaluates the increment of air deck volume and its effect on the VOD. The air gap (air deck) volume is increased stepwise from 10 to 30% of the total blast hole volume by reducing the stemming height in the collar zone. Thereafter, the VOD estimation in the 172-mm-diameter explosive column is conducted using the Dáutriche technique. It is observed that the VOD reduced with the increasing air deck volume and detonation failure is high when 30% of the blast hole volume is replaced with air deck. It is deduced that the increment of the air deck volume has an effect on the attenuation of the steady-state VOD.

By Robert A. Wilson

Los primeros pasos básicos para determinar los valores reales y los minerales concernientes, que son la base para las pruebas metalúrgicas, son presentados en este capítulo. A continuatión, eligiendo el proceso o los procesos indicados para el tratamiento de un mineral, son expuestos los temas. Todo esto es seguido por los procedimientos utilizados, el resultado de los cuales indicará la viabilidad para el tratamiento. Estas pruebas de procedimiento han sido desarrolladas, utilizadas y de probada efectividad en laboratorio con evaluaciones relativas al procesamiento de la planta. Los procedimientos especiales y poco comunes se encuentran fuera de la finalidad de este capítulo. La evaluatión de los resultados de las pruebas y su incorporatión dentro del flujograma preliminar y final para el diseno de la planta son temas igualmente expuestos. El valor de un flujograma, con balances de material y agua para el diseño de la planta, es asimismo mostrado.

Jan 1, 1982

By Mark Kuchta, Hans Engberg

The Swedish mining company LKAB operates two of the largest underground mines in the world today that together produce around 35 Mton of iron ore per year. During the 1990s, the company embarked on a massive effort to computerize its mine planning system. The goal was to combine various mine planning operations including mine surveying, geologic modeling, mine layout, production planning, and production follow-up into one modular based integrated system. The system was built around a large Oracle database and the Microstation CAD system. This overall design strategy and the various system modules are described, and some experiences gained using the system are discussed.

Jan 1, 2002