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By P. J. Lafforgue

In 1974- COGEMA (Compagnie Generale des Matieres Nucleaires) of France decided to exploit a uranium deposit discovered several years ago in a Permian formation of Southern France, near the town of Lodeve (Herault). The uranium occurs in black shales with high calcium carbonate content (7-10% CO2) and it was then necessary to use alkaline leaching. A fine grind (60-65% minue 270 mesh) was also necessary to obtain good' uranium recovery. A minimum of fresh water must be added to the alkaline system due to solution recycling. Filtration must be used because cake-washing requires less fresh water than countercurrent decantation.

Jan 1, 1982

By K. Yatsunami

NKK has developed a new cold bonded pellet process. The features of this process are; 1) it is a continuous process with 10 hours curing. 2) Products can be used as materials for various metallurgical furnaces. 3) Various kinds of slag are used as binders if necessary. 4) The quality of products is excellent. The pilot plant completed in 1981 is now being successfully operated. We are also constructing a commercial plant at our Niigata works. We produced cold pellets containing carbon as material for ferroalloys (Si-Mn), by pilot plant and used them in furnaces. Consequently, considerable economic advantages were obtained.

Jan 1, 1984

By C. E. Jordan

The fundamental properties of the Bureau of Mines patented dielectric separator were studied to provide insight regarding its design and operating characteristics. Force equations for mineral particles were derived and evaluated experimentally. High dielectric mineral recovery was proportional to the calculated effective dielectric force volume that surrounded each drum electrode wire. Electrode spacing was the most sensitive design parameter, requiring less than 0.4-cm electrode spacing for a good separation. Operating characteristics and ore characteristics were investigated. With a dielectric constant difference as small as 2, good separations were made on a laboratory scale at energy consumption below 12 kw?h/mt.

Jan 1, 1985

By S. Lu, J. P. Barta, T. W. Meikle

Three nutrient amendments and a biological seed inoculant were evaluated for use in establishing vegetative cover on waste rock substrates. Randomized blocks were placed on three substrates. Treatments included two types of organic fertilizer, mineral fertilizer, Azospirillum bacterial inoculant, plus controls. The seed mix consisted of native grass species adapted to low nutrient conditions. Canopy cover has been monitored for three growing seasons. Results indicate : 1) two of three substrates support plant growth following amendment with organic fertilizers; 2) organic fertilizers increase cover substantially over mineral fertilizer; and 3)Azospirillum had no effect on canopy cover.

Jan 1, 1999

By Edward C. Heistermann

The Falkirk Mining Company, a wholly owned subsidiary of The North American Coal Corporation, is located 80 kilometers (50 miles) north of Bismarck, North Dakota. Falkirk is under contract to provide 5.08 mil- lion tonnes (5.6 million short tons) annually to the Coal Creek Generating Station, an 1100 mega- watt electric plant owned by the Cooperative and United Power Associations of Minnesota. Coal Creek is located 2.4 kilometers (1 ½ miles) south of the Mine. Electricity from the plant is transmitted to rural electric customers in Minnesota via a 400-kilovolt D.C. power line.

Jan 1, 1982

By E. Steel

The asbestifom habit is most commonly developed in certain amphiboles and chrysotile, but other minerals may also crystallize with this unususual habit, The habit may be characterized by 1) a fibril structure, single or twinned crystals of very small widths (generally less than 0.5 inn) which have gram with a common fiber axis direction but which are disoriented in the other crystallographic directions, 2) anomalous optical properties, primarily parallel extinction, 3) unusual tensile strength, 4) high aspect ratio, and 5) flexibility. In addition, there is evidence to indicate that some amphibole asbestos may have unusual surface properties.

Jan 1, 1979

By George A. Snyder

The presence of moderate to high concentrations of colloidal clays in coal preparation plant waters can cause serious operating and economic problems for a coal company. Among the host of possible problems are the following: 1) Poor separation of clays in the plant thickener, resulting in: a) Increased ash in the clean coal. b) Increased specific gravity of the wash water and decreased coal recoveries at the desired quality. c) Increased thickener operating costs in trying to overcome the problem. 2) Decreased solid concentrations in the thickener underflow and increased pumping requirements to meet solids withdrawal requirements.

Jan 1, 1979

By Robert A. Westman

The INRED process has been developed step by step by Boliden since 1972 at MEFOS, the Foundation for Metallurgical Research, at Lulea in Sweden. The demonstration - plant is number five in this series. The purpose of this plant, which has a nominal capacity of 60,000 tonnes per year of hot metal is to: 1) prove the process on a sufficiently large scale to provide the basis for construction of production plants, 2) test various kinds of raw materials on behalf of licensees, 3) train operators of the first production plant, 4) develop the process further for special applications.

Jan 1, 1983

By Harrison R. Cooper

Approximately 40 concentrators throughout the world have successfully adopted computer control for flotation circuit operation since 1969. Successful use of flotation control, gaining up to 2% efficiencies, has largely derived from effective employment of on-stream slurry analyzers and integration of key measurement data through digital processors. Requirements for reliable measurement have also led to improved functional reliability in magnetic flow meters, pH, reagent feed, and other key elements. Methods used in computer control of flotation will be reviewed and variations in operating philosophies will be described with reference to the approaches taken to flotation automation.

Jan 1, 1979

By Marcel F. DeGuire

Pilot plant operations are described for the treatment of manganiferous zinc concentrates from the Gamsberg ore deposit in South Africa via conventional electrolytic zinc processing. Two methods were employed for the control of excess manganese ions in the pilot plant electrolyte involving (1) chemical oxidation and (2) anodic oxidation. The chemical oxidation method for manganese control was very successful. It also was found that the addition of manganese dioxide ore was not required for oxidation of ferrous iron during the neutral leach or jarosite precipitation steps. A new method (JAR process) for iron removal also was tested in the pilot plant.

Jan 1, 1978

By H. G. Fleshman

Thousands of years ago, Chinese water well drillers developed a technique for punching holes in the ground by lifting massive metal bits and letting them fall against the rock. With diligence, they could pound away about 2 feet a day. The Chinese drillers pounded holes in the ground this way for almost 2000 years. In the 1860's, French water well drillers developed a perforated bit moistened by fluids pumped into the hole through a hollow rod. The fluids carried the cuttings from the hole and spared the Frenchmen the task of bailing them out by hand.

Jan 1, 1986

By L. George Imperato

The Blocked Iron Corporation has been active for many years in the development of mineral agglomeration processes by cold chemical induration. Millions of tons of iron ore fines agglomerated by their methods have been consumed in open hearth steel making furnaces. Some of you may remember these open hearth agglomerates as the carbonate-bonded cylindrical block shown in figure 1. With the realization that iron making would create the greatest demand for agglomerates our research efforts were directed to the production of carbonate- bonded (C-B) pellets containing iron ore, flux and carbon, shown in figure 2.

Jan 1, 1968

By B. Waquet

The genesis of a hydrothermal subsea mound, by chimney debris heaping and mineralizing fluid circulating upward, induces a vertical maturation gradient. Connected porosity is easy to measure and, after mineralogical evidence, can be use as a maturation index. Thus, to understand how a rock property evaluates with maturation, it is possible to plot it against connected porosity. Results are that uniaxial compressive strength, Young's modulus, and in a lesser certitude tensile strength, abrasivity and hardness, increase very weakly with maturation until a maturation threshold (equivalent to a connected porosity equal to 0.2), and rocket to much higher values after it.

Jan 1, 2011

By Richard B. Jacob

The High Gradient Magnetic Separator (HGMS), also known as the High Gradient Magnetic Filter (HGMF), is an effective device utilized in magnetic separation. This method of separation is gaining popularity in the separation of sub-micron material containing feebly magnetics. The most common use of this type of separator is in the removal of iron stained particles to improve the brightness of kaolin clay. Potential areas for use of this magnet include: (1) desulfurization of coal (2) the clean-up of mill effluent (3) removal of fine particulate matter from municipal and industrial waste (4) desulfurization of oil

Jan 1, 1983

By Raja V. Ramani

Discussion in this section of the Handbook is limited to the working environment of miners, the mine workers themselves, and the machines used in mining (Fig. 11.0.1). The contents emphasize personnel health and safety aspects and engineering design and control practices to ensure a productive health and safety environment. Reference is to the health and safety of the individual miners as well as to the safety of the working environment. This Handbook also contains references to health and safety regulations in Chapter 3.2 and environmental protection in Chapters 3.4 and 7.3.

Jan 1, 2008

By A. A. Sobek

Controlled release systems delivering the required concentration of an effective bactericide over an extended time period have been developed by The BFGoodrich Company's ProMac® Systems group. The ProMac system is site-specific and includes a four-step approach to controlling acid mine drainage (AMD): (1) Diagnosing the problem, (2) Prescribing the treatment, (3) Supervising the application of controlled release bactericides, and (4) Honitoring the success of applied treatment. The success of the ProMac system is evidenced by improved water quality, healthy vegetation, a reduction in levels of acidophilic thiobacillus, and a corresponding increase in population of beneficial microorganisms.

Jan 1, 1986

By Chris A. Minnucci

In 1978, the U.S. Department of Energy funded a 2-year study to identify and quantify causes of the post-1969 coal mine productivity decline. A large number of factors hypothesized to have affected productivity during this period were analyzed using regression techniques. The results were particularly interesting for two of the factors--mining method and shift scheduling. The study results indicate that the use of longwall mining has an insignificant impact on overall mine productivity, compared to other methods, and mines operating on a two-production shift per day schedule are more productive than mines employing other shift schedules.

Jan 1, 1984

By E. G. Cauda

Diesel engines are a major source of underground miners? exposure to nitrogen dioxide. In an effort to reduce the exposure of underground miners to regulated and unregulated diesel emissions, primarily particulate matter, mining companies in the U.S. are retrofitting existing and introducing new engines with various exhaust aftertreatment technologies. Different aftertreatment devices, or changing the operating temperature of a selected device, can have unexpected effects on the concentration of nitrogen dioxide emitted by a diesel-powered piece of equipment. This paper provides an overview of the effects different exhaust aftertreatment technologies available to the mining industry have on no2 emissions.

Jan 1, 2010

By B. A. Hillman

Silicon is the second most abundant element on earth, exceeded only by oxygen. Silicon dioxide forms a crystalline structure of repeating SiO2 molecules which form characteristically hard, durable crystals. As a result, crystalline silica is Ubiquitous in the crustal rocks, sediments and the mineral products derived from mining. An examination of the history of studies that identify silica as a human and animal carcinogen is presented in the context of the development of a public health policy in California. The implications for the cost of conducting aggregate and other mining operations in the state are discussed.

Jan 1, 1992

By W. P. Barnett

In 1988, the U.S. Department of Energy's Pittsburgh Energy Technology Center identified three coal cleaning options for achieving flexible environmental control strategies aimed at reducing energy-related SO2 emissions. These are selective agglomeration, advanced froth flotation, and advanced cycloning. Each technology relies on maximum liberation of pyrite and other mineral matter through feed coal comminution to fine and ultrafine sizes. Research projects designed to expeditiously develop each of these technologies to the point of commercial viability were initiated. This paper will present the status of these projects and the application potential of each technology to coal beneficiation.

Jan 1, 1992